String.replaceAll howto use it ?

Hi everyone I want to replace newlines in a String with spaces. I though the use of replaceAll would be great but am having no luck with it at all.
String commentString "hello\nhello\n";
commentString.replaceAll("\\\n", " ");
I have no idea why this is not working, any help appreciated.
Cheers
Dan

public class Test {
    public static void main (String[] parameters) {
        System.out.println ("a\nb".replaceAll ("\\n", " "));
}Kind regards,
  Levi

Similar Messages

How to use String.replaceAll(String regex, String replacement)?

hi,
I'd like to use the String.replaceAll call to replace all occurrences of a pattern in a string with a string inputted from the user.
The problem is that replaceAll seems process the replacement string first. For example, the code below won't work
public class StringTest {
     public static void main(String [] arg) throws Exception {
          String input = "oooIoooIooo";
          input=input.replaceAll("I","\\");
          System.out.println(input);
}So the only option seems to be to manually process the user input string into a form that can be accepted by String.replaceAll?
The only thing I can find from looking through the API is that you'd need to convert each backslash to a double-backslash?
is this the right thing to be doing?
thanks,
asjf

just to clarify, at the moment I think the solution is to do this
public class StringTest {
     public static void main(String [] arg) throws Exception {
          String input = "oooIoooIooo";
          String raw = "\\";
          input=input.replaceAll("I",raw.replaceAll("\\\\","\\\\\\\\"));
          System.out.println(input);
}

HOWTO: Using a BC4J Application Module in an Stateless EJB Session Bean

HOWTO: Using a BC4J Application Module in an Stateless EJB Session Bean
by Steve Muench
Overview
BC4J provides automatic facilities for deploying any application module as a stateful EJB session bean. If you want to leverage the features of your BC4J application module from a stateless EJB session bean, it's not automatic but it is straightforward to implement. This howto article explains the details.
For our example, we will create a stateless EJB session bean that uses a container-managed transaction. To keep things simple, let's assume the session bean has a single public method on its remote interface named createDepartment() with the following signature:
public void createDepartment(int id, String name, String loc) throws AppException
AppException is an example of an application-specific exception that our method will throw if any problems arise during its execution.The goal of this article is to illustrate how to use the BC4J application module named com.example.hr.HRApp as part of the implementation of this createDepartment method on our stateless enterprise bean. Let's assume that the HRApp application module has a view object member named Departments, based on the com.example.hr.DeptView view object, based on the familiar DEPT table and related to the com.example.hr.Dept entity object so our view can be updateable.
Creating the Stateless Session Bean
We can start by using the JDeveloper Enterprise Bean wizard to create a new stateless session bean called StatelessSampleEJB implemented by:[list][*]com.example.StatelessSampleEJBBean (Bean class)[*]com.example.StatelessSampleEJBHome (Home interface)[*]com.example.StatelessSampleEJB (Remote interface)[list]
We then use the EJB Class Editor to add the createDepartment method to the remote interface of StatelessSampleEJB with the signature above. We edit the remote interface to make sure that it also reflects that the createDepartment method thows the AppException like this:
package com.example;
import javax.ejb.EJBObject;
import java.rmi.RemoteException;
public interface StatelessSampleEJB extends EJBObject {
void createDepartment(int id, String name, String loc)
throws RemoteException,AppException;
}Before we start adding BC4J into the picture for our implementation, our StatelessSampleEJBBean class looks like this:
package com.example;
import javax.ejb.SessionBean;
import javax.ejb.SessionContext;
public class StatelessSampleEJBBean implements SessionBean {
public void ejbCreate(){}
public void ejbActivate(){}
public void ejbPassivate(){}
public void ejbRemove(){}
public void setSessionContext(SessionContext ctx){
public void createDepartment(int id, String name, String loc)
throws AppException {
    // TODO: Implement method here
}We can double-click on the ejb-jar.xml file in our project to see the XML deployment descriptor for the bean we just created:
<ejb-jar>
   <enterprise-beans>
      <session>
         <description>Session Bean ( Stateless )</description>
         <display-name>StatelessSampleEJB</display-name>
         <ejb-name>StatelessSampleEJB</ejb-name>
         <home>com.example.StatelessSampleEJBHome</home>
         <remote>com.example.StatelessSampleEJB</remote>
         <ejb-class>com.example.StatelessSampleEJBBean</ejb-class>
         <session-type>Stateless</session-type>
         <transaction-type>Container</transaction-type>
      </session>
   </enterprise-beans>
</ejb-jar>We need to add the extra <assembly-descriptor> section in this file to indicate that the createDepartment method will require a transaction. After this edit, the ejb-jar.xml file looks like this:
<ejb-jar>
   <enterprise-beans>
      <session>
         <description>Session Bean ( Stateless )</description>
         <display-name>StatelessSampleEJB</display-name>
         <ejb-name>StatelessSampleEJB</ejb-name>
         <home>com.example.StatelessSampleEJBHome</home>
         <remote>com.example.StatelessSampleEJB</remote>
         <ejb-class>com.example.StatelessSampleEJBBean</ejb-class>
         <session-type>Stateless</session-type>
         <transaction-type>Container</transaction-type>
      </session>
   </enterprise-beans>
   <assembly-descriptor>
      <container-transaction>
         <method>
            <ejb-name>StatelessSampleEJB</ejb-name>
            <method-name>createDepartment</method-name>
            <method-params>
               <method-param>int</method-param>
               <method-param>java.lang.String</method-param>
               <method-param>java.lang.String</method-param>
            </method-params>
         </method>
         <trans-attribute>Required</trans-attribute>
      </container-transaction>
   </assembly-descriptor>
</ejb-jar>
Aggregating a BC4J Application Module
With the EJB aspects of our bean setup, we can proceed to implementing the BC4J application module aggregation.
The first thing we do is add private variables to hold the EJB SessionContext and the instance of the aggregated BC4J ApplicationModule, like this:
// Place to hold onto the aggregated appmodule instance
transient private ApplicationModule _am = null;
// Remember the SessionContext that the EJB container provides us
private           SessionContext    _ctx = null;and we modify the default, empty implementation of the setSessionContext() method to remember the session context like this:
public void setSessionContext(SessionContext ctx){ _ctx = ctx; }We add additional constants that hold the names of the J2EE datasource that we want BC4J to use, as well as the fully-qualified name of the BC4J application module that we'll be aggregating:
// JNDI resource name for the J2EE datasource to use
private static final String DATASOURCE = "jdbc/OracleCoreDS";
// Fully-qualified BC4J application module name to aggregate
private static final String APPMODNAME = "com.example.hr.HRApp";We expand the now-empty ejbCreate() and ejbRemove() methods to create and destory the aggregated instance of the BC4J application module that we'll use for the lifetime of the stateless session bean. When we're done, ejbCreate() it looks like this:
public void ejbCreate() throws CreateException {
try {
    // Setup a hashtable of environment parameters for JNDI initial context
    Hashtable env = new Hashtable();
    env.put(JboContext.INITIAL_CONTEXT_FACTORY,JboContext.JBO_CONTEXT_FACTORY);
    // NOTE: we want to use the BC4J app module in local mode as a simple Java class!
    env.put(JboContext.DEPLOY_PLATFORM, JboContext.PLATFORM_LOCAL);
    env.put(PropertyConstants.INTERNAL_CONNECTION_PARAMS,DATASOURCE);
    // Create an initial context, using this hashtable of environment params
    InitialContext ic = new InitialContext(env);
    // Lookup a home interface for the application module
    ApplicationModuleHome home = (ApplicationModuleHome)ic.lookup(APPMODNAME);
    // Using the home, create the instance of the appmodule we'll use
    _am = home.create();
    // Register the BC4J factory to handle EJB container-managed transactions
    registerContainerManagedTransactionHandlerFactory();
catch(Exception ex) {
     ex.printStackTrace();
    throw new CreateException(ex.getMessage());
}and ejbRemove() looks like this:
public void ejbRemove() {
try {
    // Cleanup any appmodule resources before getting shutdown
    _am.remove();
catch(JboException ex) { /* Ignore */ }
}The helper method named reigsterContainerManagedTransactionHandlerFactory() looks like this:
private void registerContainerManagedTransactionHandlerFactory() {
SessionImpl session = (SessionImpl)_am.getSession();
session.setTransactionHandlerFactory(
    new TransactionHandlerFactory() {
      public TransactionHandler createTransactionHandler() {
        return new ContainerManagedTxnHandlerImpl();
      public JTATransactionHandler createJTATransactionHandler() {
        return new ContainerManagedTxnHandlerImpl();
}The last detail is to use the BC4J appmodule to implement the createDepartment() method. It ends up looking like this:
public void createDepartment(int id, String name, String loc)
throws AppException {
try {
    // Connect the AM to the datasource we want to use for the duration
    // of this single method call.
    _am.getTransaction().connectToDataSource(null,DATASOURCE,false);
    // Use the "Departments" view object member of this AM
    ViewObject departments = _am.findViewObject("Departments");
    // Create a new row in this view object.
    Row newDept = departments.createRow();
    // Populate the attributes from the parameter arguments.
    newDept.setAttribute("Deptno", new Number(id));
    newDept.setAttribute("Dname", name);
    newDept.setAttribute("Loc", loc);
    // Add the new row to the view object's default rowset
    departments.insertRow(newDept);
    // Post all changes in the AM, but we don't commit them. The EJB
    // container managed transaction handles the commit.
    _am.getTransaction().postChanges();
catch(JboException ex) {
    // To be good EJB Container-Managed Transaction "citizens" we have
    // to mark the transaction as needing a rollback if there are problems
    _ctx.setRollbackOnly();
    throw new AppException("Error creating dept "+ id +"\n"+ex.getMessage());
finally {
    try {
      // Disconnect the AM from the datasource we're using
      _am.getTransaction().disconnect();
    catch(Exception ex) { /* Ignore */ }
Building a Test Client
With the EJB-Tier work done, we can build a sample client program to test this new stateless EJB Session Bean by selecting the bean in the Oracle9i JDeveloper IDE and choosing "Create Sample Java Client" from the right-mouse menu.
When the "Sample EJB Client Details" dialog appears, we take the defaults of connecting to embedded OC4J container. Clicking the (OK) button generates the following test class:
import java.util.Hashtable;
import javax.naming.Context;
import javax.naming.InitialContext;
import com.example.StatelessSampleEJB;
import com.example.StatelessSampleEJBHome;
public class SampleStatelessSampleEJBClient {
public static void main(String [] args) {
    SampleStatelessSampleEJBClient sampleStatelessSampleEJBClient =
       new SampleStatelessSampleEJBClient();
    try {
      Hashtable env = new Hashtable();
      env.put(Context.INITIAL_CONTEXT_FACTORY,
              "com.evermind.server.rmi.RMIInitialContextFactory");
      env.put(Context.SECURITY_PRINCIPAL, "admin");
      env.put(Context.SECURITY_CREDENTIALS, "welcome");
      env.put(Context.PROVIDER_URL,
              "ormi://localhost:23891/current-workspace-app");
      Context ctx = new InitialContext(env);
      StatelessSampleEJBHome statelessSampleEJBHome =
           (StatelessSampleEJBHome)ctx.lookup("StatelessSampleEJB");
      StatelessSampleEJB statelessSampleEJB;
      // Use one of the create() methods below to create a new instance
      // statelessSampleEJB = statelessSampleEJBHome.create();
      // Call any of the Remote methods below to access the EJB
      // statelessSampleEJB.createDepartment( int id, java.lang.String name, java.lang.String loc );
    catch(Throwable ex) {
      ex.printStackTrace();
}We uncomment the call to the create() method and add a few calls to the createDepartment() method so that the body of the test program now looks like this:
// Use one of the create() methods below to create a new instance
statelessSampleEJB = statelessSampleEJBHome.create();
// Call any of the Remote methods below to access the EJB
statelessSampleEJB.createDepartment( 13, "Test1","Loc1");
System.out.println("Created department 13");
statelessSampleEJB.createDepartment( 14, "Test2","Loc2");
System.out.println("Created department 14");
try {
// Try setting a department id that is too large!
statelessSampleEJB.createDepartment( 23456, "Test3","Loc3");
catch (AppException ax) {
System.err.println("AppException: "+ax.getMessage());
}Before we can successfully run our SampleStatelessSampleEJBClient we need to first run the EJB bean that the client will try to connect to. Since Oracle9i JDeveloper supports local running and debugging of the EJB-Tier without doing through a full J2EE deployment step, to accomplish this prerequisite step we just need to right-mouse on the StatelessSampleEJB node in the System Navigator and select "Run". This starts up the embedded OC4J instance and runs the EJB right out of the current out path.Finally, we can run the SampleStatelessSampleEJBClient, and see the output of the test program in the JDeveloper log window:
Created department 13
Created department 14
AppException: Error creating dept 23456
JBO-27010: Attribute set with value 23456 for Deptno in Dept has invalid precision/scale
Troubleshooting
One error that might arise while running the example is that the database connection information in your data-sources.xml for the jdbc/OracleCoreDS datasource does not correspond to the database you are trying to test against. If this happens, then double-check the file .\jdev\system\oc4j-config\data-sources.xml under the JDeveloper installation home directory to make sure that the url value provided is what you expect. For example, to work against a local Oracle database running on your current machine, listening on port 1521, with SID of ORCL, you would edit this file to have an entry like this for jdbc/OracleCoreDS :
<data-source
    class="com.evermind.sql.DriverManagerDataSource"
    name="OracleDS"
    location="jdbc/OracleCoreDS"
    xa-location="jdbc/xa/OracleXADS"
    ejb-location="jdbc/OracleDS"
    connection-driver="oracle.jdbc.driver.OracleDriver"
    username="scott"
    password="tiger"
    url="jdbc:oracle:thin:@localhost:1521:ORCL"
    inactivity-timeout="30"
/>This is the data-sources.xml file that gets used by the embedded OC4J instance running in JDeveloper.
Conclusion
Hopefully this article has illustrated that it is straightforward to utilize the full power of BC4J in local mode as part of your EJB Stateless Session Beans using container-managed transaction. This example illustrated a single createDepartment method in the enterprise bean, but by replicating the application module interaction code that we've illustrated in createDepartment, any number of methods in your stateless session bean can use the aggregated application module instance created in the ejbCreate() method.
Code Listing
The full code listing for the SampleStatelessEJB bean implementation class looks like this:
* StatelessSampleEJB
* Illustrates how to use an aggregated BC4J application module
* in local mode as part of the implementation of a stateless
* EJB session bean using container-managed transaction.
* HISTORY
* smuench/dmutreja 14-FEB-2002 Created
package com.example;
import oracle.jbo.*;
import oracle.jbo.server.*;
import javax.ejb.*;
import oracle.jbo.domain.Number;
import oracle.jbo.common.PropertyConstants;
import java.util.Hashtable;
import javax.naming.InitialContext;
import oracle.jbo.server.ejb.ContainerManagedTxnHandlerImpl;
public class StatelessSampleEJBBean implements SessionBean {
// JNDI resource name for the J2EE datasource to use
private static final String DATASOURCE = "jdbc/OracleCoreDS";
// Fully-qualified BC4J application module name to aggregate
private static final String APPMODNAME = "com.example.hr.HRApp";
// Place to hold onto the aggregated appmodule instance
transient private ApplicationModule _am = null;
// Remember the SessionContext that the EJB container provides us
private           SessionContext    _ctx = null;
public void ejbCreate() throws CreateException {
    try {
      // Setup a hashtable of environment parameters for JNDI initial context
      Hashtable env = new Hashtable();
      env.put(JboContext.INITIAL_CONTEXT_FACTORY,JboContext.JBO_CONTEXT_FACTORY);
      env.put(JboContext.DEPLOY_PLATFORM, JboContext.PLATFORM_LOCAL);
      env.put(PropertyConstants.INTERNAL_CONNECTION_PARAMS,DATASOURCE);
      // Create an initial context, using this hashtable of environment params
      InitialContext ic = new InitialContext(env);
      // Lookup a home interface for the application module
      ApplicationModuleHome home = (ApplicationModuleHome)ic.lookup(APPMODNAME);
      // Using the home, create the instance of the appmodule we'll use
      _am = home.create();
      // Register the BC4J factory to handle EJB container-managed transactions
      registerContainerManagedTransactionHandlerFactory();
    catch(Exception ex) {
       ex.printStackTrace();
      throw new CreateException(ex.getMessage());
public void ejbActivate(){}
public void ejbPassivate(){}
public void ejbRemove(){}
public void setSessionContext(SessionContext ctx){ _ctx = ctx; }
public void createDepartment(int id, String name, String loc)
throws AppException {
    try {
      // Connect the AM to the datasource we want to use for the duration
      // of this single method call.
      _am.getTransaction().connectToDataSource(null,DATASOURCE,false);
      // Use the "Departments" view object member of this AM
      ViewObject departments = _am.findViewObject("Departments");
      // Create a new row in this view object.
      Row newDept = departments.createRow();
      // Populate the attributes from the parameter arguments.
      newDept.setAttribute("Deptno", new Number(id));
      newDept.setAttribute("Dname", name);
      newDept.setAttribute("Loc", loc);
      // Add the new row to the view object's default rowset
      departments.insertRow(newDept);
      // Post all changes in the AM, but we don't commit them. The EJB
      // container managed transaction handles the commit.
      _am.getTransaction().postChanges();
    catch(JboException ex) {
      // To be good EJB Container-Managed Transaction "citizens" we have
      // to mark the transaction as needing a rollback if there are problems
      _ctx.setRollbackOnly();
      throw new AppException("Error creating dept "+ id +\n"+ex.getMessage());
    finally {
      try {
        // Disconnect the AM from the datasource we're using
        _am.getTransaction().disconnect();
      catch(Exception ex) { /* Ignore */ }
private void registerContainerManagedTransactionHandlerFactory() {
    SessionImpl session = (SessionImpl)_am.getSession();
    session.setTransactionHandlerFactory(
      new TransactionHandlerFactory() {
        public TransactionHandler createTransactionHandler() {
          return new ContainerManagedTxnHandlerImpl();
        public JTATransactionHandler createJTATransactionHandler() {
          return new ContainerManagedTxnHandlerImpl();

Hi Steve, It4s me again;
About the question I made, I tried with a single assembly-descriptor tag and a single container-transaction tag in the deployment descriptor of the session bean and these were the results.
java.lang.NullPointerException
     void com.evermind.server.rmi.RMIConnection.EXCEPTION_ORIGINATES_FROM_THE_REMOTE_SERVER(java.lang.Throwable)
     java.lang.Object com.evermind.server.rmi.RMIConnection.invokeMethod(com.evermind.server.rmi.RMIContext, long, long, java.lang.reflect.Method, java.lang.Object[])
     java.lang.Object com.evermind.server.rmi.RemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
     java.lang.Object com.evermind.server.rmi.RecoverableRemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
     java.lang.Object com.evermind.server.ejb.StatelessSessionRemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
     void __Proxy1.modificaEnvoltura(java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.String)
     void SamplemdeController.envolturaControlEJBClient.main(java.lang.String[])
Then I tried with multiple assembly-descriptor tags each with a single container-transaction tag and the results were:
java.lang.NullPointerException
     void com.evermind.server.rmi.RMIConnection.EXCEPTION_ORIGINATES_FROM_THE_REMOTE_SERVER(java.lang.Throwable)
     java.lang.Object com.evermind.server.rmi.RMIConnection.invokeMethod(com.evermind.server.rmi.RMIContext, long, long, java.lang.reflect.Method, java.lang.Object[])
     java.lang.Object com.evermind.server.rmi.RemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
     java.lang.Object com.evermind.server.rmi.RecoverableRemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
     java.lang.Object com.evermind.server.ejb.StatelessSessionRemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
     void __Proxy1.modificaEnvoltura(java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.String)
     void SamplemdeController.envolturaControlEJBClient.main(java.lang.String[])
Finally I tried with a single assembly-descriptor and multiple container tags and the results were:
java.lang.NullPointerException
     void com.evermind.server.rmi.RMIConnection.EXCEPTION_ORIGINATES_FROM_THE_REMOTE_SERVER(java.lang.Throwable)
     java.lang.Object com.evermind.server.rmi.RMIConnection.invokeMethod(com.evermind.server.rmi.RMIContext, long, long, java.lang.reflect.Method, java.lang.Object[])
     java.lang.Object com.evermind.server.rmi.RemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
     java.lang.Object com.evermind.server.rmi.RecoverableRemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
     java.lang.Object com.evermind.server.ejb.StatelessSessionRemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
     void __Proxy1.modificaEnvoltura(java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.String)
     void SamplemdeController.envolturaControlEJBClient.main(java.lang.String[])
How can I make my Stateless Session bean work out?

String.replaceAll strange behavior...

I have found strange behavior of String.replaceAll method:
"aaaabaaaa".replaceAll("b","a"); // working fine
"aaaabaaaa".replaceAll("b","a${"); // throws an exceptionThat could be probably a bug?
p.s. using jdk_1.6.0_12-b04

Welcome to the Sun forums.
>
"aaaabaaaa".replaceAll("b","a${"); // throws an exception
Please always copy/paste the [exact error message|http://pscode.org/javafaq.html#exact]. We do not have crystal ball, and cannot see the output on your PC.
>
That could be probably a bug? >(chuckle) It has more to do with special characters in Strings, that need to be escaped. I am not up on the fine details, but try this code.
import javax.swing.*;
class TestStringReplace {
public static void main(String[] args) {
    String result = "aaaabaaaa".replaceAll("b","c"); // working fine
    JOptionPane.showMessageDialog(null, result);
    result = "aaaabaaaa".replaceAll("b","c\\${"); // chars escaped
    JOptionPane.showMessageDialog(null, result);
}

Regular Expression Fails String replaceAll

I am trying to use regular expressions to replace double backslashes in a string with a single backslash character. I am using version 1.4.2 SDK. Upon invoking the replaceAll method I get a stack trace. Does this look like a bug to anyone?
String s = "text\\\\"; //this results in a string value of 'text\\'
String regex = "\\\\{2}"; //this will match 2 backslash characters
String backslash = "\\";
s.replaceAll(regex,backslash); java.lang.StringIndexOutOfBoundsException: String index out of range: 1
     at java.lang.String.charAt(String.java:444)
     at java.util.regex.Matcher.appendReplacement(Matcher.java:551)
     at java.util.regex.Matcher.replaceAll(Matcher.java:661)
     at java.lang.String.replaceAll(String.java:1663)
     at com.msdw.fid.fitradelinx.am.client.CommandReader.read(CommandReader.java:55)
     at com.msdw.fid.fitradelinx.am.client.CommandReader.main(CommandReader.java:81)
Exception in thread "main"

Skinning the cat -
public class Fred12
    public static void main(String[] args)
            String s = "text\\\\"; //this results in a string value of 'text\\'
            String regex = "[\\\\]{2}"; //this will match 2 backslash characters
            String backslash = "\\\\";
            System.out.println(s.replaceAll(regex,backslash));
            String s = "text\\\\"; //this results in a string value of 'text\\'
            String regex = "(\\\\){2}"; //this will match 2 backslash characters
            String backslash = "\\\\";
            System.out.println(s.replaceAll(regex,backslash));
            String s = "text\\\\"; //this results in a string value of 'text\\'
            String regex = "(?:\\\\){2}"; //this will match 2 backslash characters
            String backslash = "\\\\";
            System.out.println(s.replaceAll(regex,backslash));
            String s = "text\\\\"; //this results in a string value of 'text\\'
            String regex = "(?:\\\\)+"; //this will match 2 or more backslash characters
            String backslash = "\\\\";
            System.out.println(s.replaceAll(regex,backslash));
            String s = "text\\\\"; //this results in a string value of 'text\\'
            String regex = "\\\\\\\\"; //this will match 2 backslash characters
            String backslash = "\\\\";
            System.out.println(s.replaceAll(regex,backslash));
}

String.replaceAll doesn't work

Hi,
I hope this is the correct forum to post about this problem. It's not a compiler error, it rather seems to be an interpreter or a logical error.
Please consider this test program I wrote to clarify the problem.
public class Test {
    public static void main( String args[]) {
     String someString = "Hello $place!";
     System.out.println( someString.replaceAll( "place", "world"));
     System.out.println( someString.replaceAll( "$place", "world"));
}The method String.replaceAll should replace all occurences of regex with replacement.
Also see http://java.sun.com/j2se/1.4.2/docs/api/java/lang/String.html#replaceAll(java.lang.String, java.lang.String)
So, one should think my test program would have the following output:
Hello $world!
Hello world!Alas, it isn't so. The program outputs the following using SDK 1.2.4:
Hello $world!
Hello $place!The String.replaceAll method doesn't seem to replace occurences if they are preceeded of "$". Or am I just missing something?

The String.replaceAll method doesn't seem to replace
occurences if they are preceeded of "$". Or am I just
missing something?You're right. The method replaceAll is expecting a [url http://java.sun.com/j2se/1.4.2/docs/api/java/util/regex/Pattern.html]regular expression. See there how to escape special control chars like $ which means 'end of line'.

PatternSyntaxException when calling String.replaceAll in multithreaded app

Dear,
Someone ever encountered or knows of problems when invoking String.replaceAll in a multithreaded application (JDK 1.4.2)?
I have an application that invokes replaceAll on a String and that runs just fine when only a single thread is active, but once multiple threads execute the same code, each on its own String instance, the following stack is produced (more often than not).
java.util.regex.PatternSyntaxException: Unknown character category {Digit} near index 9
^\p{Digit}
^
at java.util.regex.Pattern.error(Unknown Source)
at java.util.regex.Pattern.familyError(Unknown Source)
at java.util.regex.Pattern.retrieveCategoryNode(Unknown Source)
at java.util.regex.Pattern.family(Unknown Source)
at java.util.regex.Pattern.sequence(Unknown Source)
at java.util.regex.Pattern.expr(Unknown Source)
at java.util.regex.Pattern.compile(Unknown Source)
at java.util.regex.Pattern.<init>(Unknown Source)
at java.util.regex.Pattern.compile(Unknown Source)
at java.lang.String.replaceAll(Unknown Source)
The 1.4.2 source code seems to use a static HashMap (java.util.regex.Pattern#retrieveCategoryNode) to store some read only data, but it looks like the initialization of that HashMap in an multi threaded environment is not 'locked'. Could that be the/an issue? Anybody any thoughts?
Thanks,
Peter

I ran peter's program on a hyperthreaded Intel P4 box and XP Pro. XP reports that there are 2 processors.
I used 1.4.2_06 and 1.5.0_01, with both -client and -server options.
The program was run with numThreads 10 and loadPattern 0 and 1.
The program was run 50 times for each of the configurations. Only one resulted in failures, as follows:
Java version     cli/svr          Pgm Parms   # Failures
1.5.0_01     -client          10, 0          0
                    10, 1          0
          -server          10, 0          0
                    10, 1          0
1.4.2_06     -client          10, 0          10
                    10, 1          0
          -server          10, 0          0
                    10, 1          0
Of the 10 failures, 1 reported 3 errors, 2 reported 2 errors, and 7 reported 1 error.
The triple-error report is below:
"C:\Program Files\Java\jdk1.4.2_06\bin\java.exe" -client PatternProblem 10 0
Thread-7:Unknown character category {Digit} near index 9
^\p{Digit}
         ^
Thread-5:Unknown character category {Digit} near index 9
^\p{Digit}
         ^
Thread-3:Unknown character category {Digit} near index 9
^\p{Digit}
         ^
Note that this wording is not the same as peter encountered. The thread number varied,
apparently randomly, from 0 to 8

String.replaceAll bottleneck

Hi All,
I have written a method to make a string "safe" for xml, by encoding characters that need to be replaced.
It works just fine using String.replaceAll as below, but when i profile the app i see that it is a performance bottleneck.
I can see that it is creating a lot of Strings so this is part of the problem.
From reading through the forum I can see regexs used frequently for this type of problem, but it seems that they will not be more efficient than my existing approach.
I see that StringBuffer has a replace method but i'm not sure that it is a good fit for my problem?
Can anybody suggest a more efficient solution?
Your help is much appreciated!
emhart
Here's my existing method:
public static String makeSafeForXML(String str)
String result = str;
result = result.replaceAll("&", "&");
result = result .replaceAll(">", ">");
result = result .replaceAll("<", "<");
result = result .replaceAll("'", "'");
result = result .replaceAll("\"", """);
return result ;
}

That method doesn't make any sense to me:
replacing strings with the same exact string?
also the last one isn't correct, maybe missing a \ ?
Also, you do realize that the replaceAll method uses the first argument as a regex to match patterns in the string?
My apologies if I'm missing something.
But if this really is what you want, then maybe this is faster (I haven't measured any times though):public static String makeSafeForXML2(String str)
    StringBuilder sb = new StringBuilder(str);
    for (int i = 0; i < sb.length(); i++) {
        switch (sb.charAt(i)) {
            case '&':
                sb.replace(i, i + 1, "&");
                break;
            case '>':
                sb.replace(i, i + 1, ">");
                break;
            case '<':
                sb.replace(i, i + 1, "<");
                break;
            case '\'':
                sb.replace(i, i + 1, "'");
                break;
            case '"':
                sb.replace(i, i + 1, "\"");
                break;
    return sb.toString();
}

Matcher vs. String.replaceAll

I have been experiencing a problem attempting to use an expression such as:
s = s.replaceAll("PATTERN","REPLACEMENT");
to replace certain regular expressions in a document. When using the Matcher to replace Strings as follows there is no problem, but using the same pattern with String.replaceAll doesn't seem to perform the replacement.
Pattern pattern = Pattern.compile("PATTERN",Pattern.DOTALL);
Matcher matcher = pattern.matcher(s);
s = matcher.replaceAll("REPLACEMENT");
The only thing I can think of is that the Pattern.DOTALL options allows the match to take succeed, where it wouldn't otherwise. Therefore I was wondering if there an equivalent for the String.replaceAll method perhaps? Any ideas?
Thanks very much,
Ross Butler

I'm having trouble believing that PATTERN and REPLACEMENT are the real string you're using, but it's probably not important, since it sounds like you probably diagnosed the problem yourself.
According to the Javadocs, replaceAll gives the same result as Pattern.compile(regex).matcher(str).replaceAll(repl), but obviously that wouldn't necessarily be true if you add extra parameters somewhere in there, so I would say that replaceAll is more of a convenience method that you use when you don't need any extra parameters.
However, if you need to use DOTALL or something else similar, you'll need the longer way using Matcher.
That shouldn't stop you from writing your own convenience method, though. :)

String.replaceAll problem

I need to replace a single quote ( ' ) in a string with two single quotes. I am trying to use String.replaceAll method but it does not work. I guess my regular expression is not correct. I have tried several combinations already.
text.replaceAll(".'.","''");
text.replaceAll("'","''");
text.replaceAll("\\'","''"); None of them have worked. It does not change the text as I'd like it to.

It's been at least a week since I've posted this:
Since regex patterns are involved, you can use the simpler replace method:
str = str.replace("'", "''");By the way, I hope you not doing this to insert text into a database!

Trouble with String.replaceAll( )

Hi,
I have a string which contains instances of the backslash character followed by the double quote character and I'd like to replace those two characters with just a double quote. Or to put it slightly differently, I'd like to remove all backslash characters which precede double quotes. It seems like this should be straight-forward, but for some reason, I'm not getting the results I expect.
Here is my code:
          String s1 = "Foo\\\"Bar";
          System.out.println("s1 = " + s1);
          int len = s1.length( );
          System.out.println("s1.length( ) = " + len);
          String s2 = s1.replaceAll("\\\"", "\"");
          System.out.println("s2 = " + s2);
          len = s2.length( );
          System.out.println("s2.length( ) = " + len);
And here is the corresponding output:
s1 = Foo\"Bar
s1.length( ) = 8
s2 = Foo\"Bar
s2.length( ) = 8
So, the string isn't being changed at all. What am I doing wrong? Thanks in advance for any replies.
-ts1971

Melanie_Green wrote:
string.replaceAll()Takes two arguments, the first is a regular expression, the second is a String. Regular expressions have their own syntax compared to Strings, to match a single black slash in a regular expression you must write "\\\\".
MelJust a little nit-pick: the second parameter is not a plain String but a "regex replacement String". In it, the following characters have a special meaning and therefore need to be escaped if you'd like to use them as literals:
$    // used for match-group interpolation
\    // used to escape '$' and '\' itself

String.replaceAll(String,"\\")

Hello, i tried this here but strangely it does not work.
The machine gives an ArrayIndexOutOfBoundsException...
Seems the method does not run with the "\" character. What did i do wrong?
public class Zeichen {
     public static void main(String[] args) {
          Zeichen ch = new Zeichen();
     public Zeichen() {
          String str = "this";
          str=str.replaceAll("i","\\");
          System.out.println(str);
}

The method header for the String.replaceAll() that you are trying to use is as follows
public String replaceAll(String regex,
                         String replacement)[\code]
The string "i" that you are entering is not a regular expression, which are listed at http://java.sun.com/j2se/1.4/docs/api/java/util/regex/Pattern.html#sum

Pass multiple query strings to url using HTTPWebRequest

I'm trying to read data from API (in Json format) and load it into SQL server using script task in SSIS.
Dim Request1 As System.Net.HttpWebRequest = DirectCast(System.Net.HttpWebRequest.Create(URL), System.Net.HttpWebRequest)
Dim Object1 As [Object]
Dim Response1 As System.Net.HttpWebResponse = Nothing
Dim reader1 As System.IO.StreamReader
Dim myResponseString As String
Request1.Headers.Add("Authorization: Token *****")
Try
Response1 = DirectCast(Request1.GetResponse(), System.Net.HttpWebResponse)
reader 1= New System.IO.StreamReader(Response1.GetResponseStream())
myResponseString = reader.ReadToEnd()
I'm able to do this with the URL. However, the requirement now is to pass different query strings to the URL and load the data into SQL.
Could someone please provide the code sample to achieve this.
Thanks

If we sent you a code you must try and tell that it doesn't work or that's not what I want, this is better than repeating the same question again and again. Here you go another snippet for httpwebrequest with querstrings and tested:
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Try
Dim request As HttpWebRequest = DirectCast(HttpWebRequest.Create(New Uri("http://www.google.com?querstring1=1&querystring2=2")), HttpWebRequest)
request.BeginGetResponse(New AsyncCallback(AddressOf ReadCallback), request)
Catch ex As WebException
End Try
End Sub
Private Sub ReadCallback(asynchronousResult As IAsyncResult)
Dim request As HttpWebRequest = DirectCast(asynchronousResult.AsyncState, HttpWebRequest)
Dim response As HttpWebResponse = DirectCast(request.EndGetResponse(asynchronousResult), HttpWebResponse)
Using streamReader1 As New StreamReader(response.GetResponseStream())
Dim resultString As String = streamReader1.ReadToEnd()
Dim result As String = Convert.ToString("Using HttpWebRequest: ") & resultString
End Using
End Sub
Fouad Roumieh

Sharepoint 2013 :Content Search Web part Property Filter By Query String - How to use ?

Hi,
I would like to filter data that is displayed in content search web part by using URL.
I tried to use Value of a parameter from a URL - Query String.Parameter1
But have no idea how to use it.
Can someone help me pleas ?

duplicate thread
http://social.msdn.microsoft.com/Forums/en-US/f9fef155-1aa3-43b5-b285-5eae5d036b8d/content-search-webpart-property-filter-by-query-string-how-to-use-?forum=sharepointgeneral
My Blog- http://www.sharepoint-journey.com|
If a post answers your question, please click Mark As Answer on that post and Vote as Helpful

How to print a string with out using main method??

how to print a string with out using main method??
if we can tell me with example?
thanks in adavance
raja

Hi,
actually there's none. The UITableView class needs to "know" the tableView's height so either it can calc <number of rows> times <row height> or it has to sum the height of each single row.
If the row which needs to be of different size always is the first or the last row you can user a tableHeader or tableFoot view.
Regards
Dirk

String.replaceAll howto use it ?

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