Prompt java to read in a file

Hi I am trying to finish a program that analyzes data and in the main method of my program I need a command that allows me to prompt the user of the program for a file to read into the program so that the program can run its analysis. What would such a command be and please give me some example code of how it would work.

Note: This thread was originally posted in the [Java Programming|http://forums.sun.com/forum.jspa?forumID=31] forum, but moved to this forum for closer topic alignment.

Similar Messages

Where does this java program read a text file and how does it output the re

someone sent this to me. its a generic translator where it reads a hashmap text file which has the replacement vocabulary etc... and then reads another text file that has what you want translated and then outputs translation. what i don't understand is where i need to plugin the name of the text files and what is the very first line of code?
[code
package forums;
//references:
//http://forums.techguy.org/development/570048-need-write-java-program-convert.html
//http://www.wellho.net/resources/ex.php4?item=j714/Hmap.java
import java.util.Map;
import java.util.HashMap;
import java.util.Iterator;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.FileReader;
public class Translate {
public static void main(String [] args) throws IOException {
if (args.length != 2) {
System.err.println("usage: Translate wordmapfile textfile");
System.exit(1);
try {
HashMap words = ReadHashMapFromFile(args[0]);
System.out.println(ProcessFile(words, args[1]));
} catch (Exception e) {
e.printStackTrace();
// static helper methods
* Reads a file into a HashMap. The file should contain lines of the format
* "key\tvalue\n"
* @returns a hashmap of the given file
@SuppressWarnings("unchecked")
private static HashMap ReadHashMapFromFile(String filename) throws FileNotFoundException, IOException {
BufferedReader in = null;
HashMap map = null;
try {
in = new BufferedReader(new FileReader(filename));
String line;
map = new HashMap();
while ((line = in.readLine()) != null) {
String[] fields = line.split("\\t", 2);
if (fields.length != 2) continue; //just ignore "invalid" lines
map.put(fields[0], fields[1]);
} finally {
if(in!=null) in.close(); //may throw IOException
return(map); //returning a reference to local variable is safe in java (unlike C/C++)
* Process the given file
* @returns String contains the whole file.
private static String ProcessFile(Map words, String filename) throws FileNotFoundException, IOException {
BufferedReader in = null;
StringBuffer out = null;
try {
in = new BufferedReader(new FileReader(filename));
out = new StringBuffer();
String line = null;
while( (line=in.readLine()) != null ) {
out.append(SearchAndReplaceWordsInText(words, line)+"\n");
} finally {
if(in!=null) in.close(); //may throw IOException
return out.toString();
* Replaces all occurrences in text of each key in words with it's value.
* @returns String
private static String SearchAndReplaceWordsInText(Map words, String text) {
Iterator it = words.keySet().iterator();
while( it.hasNext() ) {
String key = (String)it.next();
text = text.replaceAll("\\b"+key+"\\b", (String)words.get(key));
return text;
* @returns: s with the first letter capitalized
String capitalize(String s)
return s.substring(0,0).toUpperCase() + s.substring(1);
}

without what arguments?Without any arguments. If there are no arguments, there are no arguments of any kind. If you have a zoo with no animals in it, it's not meaningful to ask whether the animals which are not there are zebras or elephants.
does it prompt me to give it a text file name?Apparently.
when i run it this is all i get:
usage: Translate wordmapfile textfile
Press any key to continue...Right. And "wordmapfile" is almost certainly supposed to be a file that holds the word map, and "textfile" is almost certainly the file of text that it's going to translate.

How to make an applet to read the Text file present inside a jar

Hi All,
I have writen one applet named ReadFile.java which reads a text file present in the same directory and does some manipulation of text file contents.
The applet code runs successfully when i run the applet in command prompt like
{color:#ff0000}*java ReadFile*{color}
And i am getting the needed results.
Then i made a jar file with the applet code and text file as
{color:#ff0000}*jar cvf rf.jar ReadFile.class File1.txt*{color}
Then i have inlcuded this applet inside a html file as
{color:#ff0000}*<applet code= "ReadFile.class" width= "500" height= "300" archive = "rf.jar" ></applet>*{color}
after this when i load the html file, the applet code is not executed fully. Its throwing FileNotFoundException: File1.txt.
Applet is not recognizing trhe text file present inside the jar file.
Can any body explain me how to overcome this problem. Any setting needs to be done for making the applet indicate the presence of Text file inside the jar file.

what code in your applet gets the text file and reads it? are you using getResource or something similar?

How do I read a text file in a Jar Executable?

Hello All,
I have a need to package a text file into a Jar Exectable file and then have my java code read that text file in using a BufferedReader. Can anyone out there tell me how to do this? My first question is how do I reference this file by the path name? O, I'm also using Windows.
Thanks for your help.
Karl

I have the same problem with kportner . I did by joop_eggen but I got the error at:
BufferedReader in = new InputStreamReader(is);Can't conver from BufferedReader to InputStreamReader
When I up my applet to server and get it from client. My applet couldn't read the text file.
Any one help me!
Thanks.

Reading a binary file (byte swapping?): HELP!

Hi,
Below are 2 simple programs, one in C and the other in Java that read a binary file. The first 3 integer numbers read by the C program are:
910, 1024437292, 100002
The first 3 integer numbers read by the Java program are:
-1912406016, 749473597, -1568276224
The file was written with another C program. The values read by the C program listed here are correct.
I supect that I have a byte swapping problem. Do you know how I can solve this problem? I really can't change the format of the input file.
Thanks for your help,
Miguel
#include <stdio.h>
void main(int argc, char *argv[]) {
long buff[600];
FILE *fp = fopen("c:\\inetpub\\wwwroot\\super\\wvdot3.awg","r");
fread(buff,sizeof(int),512,fp);
int sz = sizeof(int);
import java.io.*;
public class test {
public static void main(String[] args) {
try {
DataInputStream din = new DataInputStream(new BufferedInputStream
(new FileInputStream("c:\\inetpub\\wwwroot\\super\\wvdot3.awg")));
int nrecs = din.readInt();
int version = din.readInt();
int routetype = din.readInt();
System.out.println("read: " + nrecs + " " + version + " " + routetype);
} catch (IOException exc) {
System.out.println("IOException: " + exc);

Yeah, the problem is byte ordering. I had to deal with the same thing, since Java is always big endian, and intel and DEC Alpha are both little endian. I assume you're original program runs on Intel.
I ended up creating a new LittleEndianDataInputStream. Unfortunately, you can't just extend DataInputStream since all it's methods are final. You can however copy the source, rename it, and then change all the multi-byte numeric methods to reverse the byte ordering.
For example, here is the code for the original and little endian version of readInt()
<code>
// DataInputStream
public final int readInt() throws IOException {
InputStream in = this.in;
int ch1 = in.read();
int ch2 = in.read();
int ch3 = in.read();
int ch4 = in.read();
if ((ch1 | ch2 | ch3 | ch4) < 0)
throw new EOFException();
return ((ch1 << 24) + (ch2 << 16) + (ch3 << 8) + (ch4 << 0));
// LittleEndianDataInputStream
public int readInt() throws IOException
int ch1 = in.read();
int ch2 = in.read();
int ch3 = in.read();
int ch4 = in.read();
if ((ch1 | ch2 | ch3 | ch4) < 0)
throw new EOFException();
// here's the change
return ( (ch4 << 24) + (ch3 << 16) + (ch2 << 8) + (ch1 << 0) );
</code>

Reading a XML file in a standalone java application

Hi,
What are my options if I have a standalone java application running outside any app. server and I need to read an XML file, probably read some of the attributes in the file...? Please explain clearly as I'm new to this. Appreciate your help.
Thanks,
Mahdad

nope you don't need a DTD
you have to write your Java code in a way that doesn't rely too much on the structure:
- avoid getFirstChild().getFirstChild()... because you know that this element is first grandson of that element)
- prefer using getElementByTagName() or some XPath() API
but if the XML completely changes, well, yeah, you have to do some programmation: better think well your document structure in the beginning.

Is there any way to read the pdf file in java

Hai,
i need some advice from anyone that is there anyway to read the pdf file directly from java...
Without converting to other files(txt,html)
if it is possible please help me..
Thank you

Or use the Adobe one (search the adobe site). Or search this forum, this is one of the Top Ten Qestions Asked here.

URGETN HELP NEEDED! JAVA APPLET READING FILE

Hi everyone
I need to hand in this assignment today
Im trying to read from a file and read it onto the screen, my code keeps showing up an error
'missing method body, or declare abstract'
This is coming up for the
public statuc void main(String[] args);
and the
public void init();
Here is my code:
import java.io.*;
import java.awt.*;
import java.applet.*;
public class Empty_3 extends Applet {
TextArea ta = new TextArea();
public static void main(String[] args);
public void init();
setLayout(new BorderLayout());
add(ta, BorderLayout.CENTER);
try {
InputStream in =
getClass().getResourceAsStream("test1.txt");
InputStreamReader isr =
new InputStreamReader(in);
BufferedReader br =
new BufferedReader(isr);
StringWriter sw = new StringWriter();
PrintWriter pw = new PrintWriter(sw);
String line;
while ((line = br.readLine()) != null) {
pw.println(line);
ta.setText(sw.toString());
} catch (IOException io) {
ta.setText("Ooops");
Can anyone help me please?
Is this the best way of doing this? Once i read the file i want to perform a frequency analysis on the words so if there is a better method for this then please let me know!
Thankyou
Matt

Whether it is urgent or not, does not interest us. It might be urgent for you but for nobody else.
Writing all-capitals is considered shouting and rude.
// Use code tags for source.

How to know they is space or carrier return when java read a text file.

Hi,
Please help.
How to know they is space or carrier return when java read a text file.
The reason is that. I want to use java for loop to read each part of value. for example: first part is the items name. After the space (I need to tell java when this is a space here and its need to skip) , following by the items prices in double value and space again (need to skip also) and etc.
item name1
item name2
item name3
item name4
item name5
<--- here is the space to skip and another loop to read following items prices
item price1
item price2
item price3
item price4
item price5
<--- here is another spcae again. and so on
thank in advance!

You can check to see if the sting you read in is just nothing, depending on how you're reading it in:
if((str = inStream.readLine().trim().equals("")))
// skip and get ready for the next section
else
// handle the next item
The trim() method gets rid of all leading and trailing spaces and I'm assuming you're using a stream that can use the readLine() method that returns a String.
I hope this is clear. Let me know if it isn't, I'll try and word it different, or post how you're reading the values in if you need more help.

Can't read a text file using java

Hi All
I am trying to read a log file.
ProgramA keeps updating the log file, while my program ProgramB reads it.
For some readson my ProgramB is not able to read the last two lines in the log file. If I run the program in debug mode it is reading all the lines.
This is having me frustrated.
Please let me know if there is a way to read entire contents.
Here is how I am reading the files ( 2ways)
     private static String readFileAsString(String filePath)
    throws java.io.IOException{
        StringBuffer fileData = new StringBuffer(1000);
        FileReader fr = new FileReader(filePath);
        BufferedReader reader = new BufferedReader(fr);
        char[] buf = new char[1024];
        int numRead=0;
        while((numRead=reader.read(buf)) != -1){
            String readData = String.valueOf(buf, 0, numRead);
            fileData.append(readData);
            buf = new char[1024];
        reader.close();
        fr.close();
        return fileData.toString();
       * Fetch the entire contents of a text file, and return it in a String.
       * This style of implementation does not throw Exceptions to the caller.
       * @param aFile is a file which already exists and can be read.
       static public String readFileAsString(String filePath) {
         //...checks on aFile are elided
         StringBuffer contents = new StringBuffer();
         //declared here only to make visible to finally clause
         BufferedReader input = null;
         try {
           //use buffering, reading one line at a time
           //FileReader always assumes default encoding is OK!
           input = new BufferedReader( new FileReader(filePath) );
           String line = null; //not declared within while loop
           * readLine is a bit quirky :
           * it returns the content of a line MINUS the newline.
           * it returns null only for the END of the stream.
           * it returns an empty String if two newlines appear in a row.
           while (( line = input.readLine()) != null){
             contents.append(line);
             contents.append(System.getProperty("line.separator"));
         catch (FileNotFoundException ex) {
           ex.printStackTrace();
         catch (IOException ex){
           ex.printStackTrace();
         finally {
           try {
             if (input!= null) {
               //flush and close both "input" and its underlying FileReader
               input.close();
           catch (IOException ex) {
             ex.printStackTrace();
         return contents.toString();
       }

If you're using JDK 5 or later, you could use the Scanner class for input information. See below:
try {
               Scanner reader = new Scanner(new File("C:\\boot.ini"));
               StringBuilder sb = new StringBuilder();
               while (reader.hasNextLine()) {
                    sb.append(reader.nextLine());
                    sb.append(System.getProperty("line.separator"));
               System.out.println(sb.toString());
          } catch (FileNotFoundException e) {
               e.printStackTrace();
          }

How to read a text file using Java

Guys,
Good day!
Please help me how to read a text file using Java and create/convert that text file into XML.
Thanks and God Bless.
Regards,
I-Talk

     public void fileRead(){
             File aFile =new File("myFile.txt");
         BufferedReader input = null;
         try {
           input = new BufferedReader( new FileReader(aFile) );
           String line = null;
           while (( line = input.readLine()) != null){
         catch (FileNotFoundException ex) {
           ex.printStackTrace();
         catch (IOException ex){
           ex.printStackTrace();
     }This code is to read a text file. But there is no such thing that will convert your text file to xml file. You have to have a defined XML format. Then you can read your data from text files and insert them inside your xml text. Or you may like to read xml tags from text files and insert your own data. The file format of .txt and .xml is far too different.
cheers
Mohammed Jubaer Arif.

Java mapping - for reading the binary file contents and changing filename

Hi,
I have already gone through the various bolgs and threads and have not been able to find a solution to my problem.
One blog did give some idea but did not help- "JAAPPING", an alternate way of reading a CSV file
I am not very good in java but have been trying some out recently to fulfill the interface requirements.
I would really appreciate if you could help am I am giving below the detailed scenario below.
Part 1- working fine - The incoming file looks like:
:20:STMEMU096868DUBE
:25:001180256210
:28C:00371/00001
:60F:C090617AED742136,92
:61:0906300630CD34,27FINTCREDIT INTEREST
26MAY2009 TO 25JUN2009
:62F:C090630AED742171,19
:64:C090630AED742171,19
The file name as received is:TCDE.BLQSAM.SAEA2682.C0084025.A9G24T58.20090724195908
This file without any conversion is placed on XI server dircetory folder.
Part 2 - need to develop
The file should now be renamed according to the incoming value in 2nd line - specifically the 12 digit value 001180256210 and placed on the R/3 dircetory folder.
The new file name in the above example should be:
AC_NO_001180256210_datetime
The module for the above was created and the last time I checked it was working.
However, when I wanted to do final testing in Dev and move the changes further, the module has seemed to have stopped working so I need an alternate solution fast.
I was thinking of doing the Java mapping as I will be more in control as to what is going on thereby reducing the dependency.
There is no need to create any target xml structure as the file as it is needs to be placed in the target folder with a new name.
I can get the file name in UDF which I have already created but i am not usre if it working.
Can you please help?
Any help will be greatly appreciated.
Regards,
Archana
+44-7867636863

Hi Stephen
The xml must be getting added in the below part of the code. It is coming from arg[0]
You can put a check and get it removed.
while ((len = arg0.read(buffer)) != -1) {
arg1.write(buffer, 0, len);
Regards
Osman

How to Read a CAB File from JAVA?

Hi,
Anyone knows how to read a CAB File from java. I need to read a property file of txt file that is packaged in CAB file & then based on that, I have to do processing. Is there anyway to do it.
I had tried using java.util.zip.ZipFile Class, but it does work for JAR, but not for CAB.
siva.

Perhaps there's something in the Cabinet SDK that will help:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dncabsdk/html/cabdl.asp

Reading/Writing .xlsx files using Webdynpro for Java

Dear All
I have a requirement to read/write excel files in .xlsx format. I am good in doing it with .xls format using jxl.jar. The jxl.jar doesn't support .xlsx format. Kindly help me in understanding how do I need to proceed on reading/writing .xlsx files using Webdynpro for Java.
Thanks and Regards
Ramamoorthy D

i am using jdk 1.6.22 and IBM WebSphere
when i use poi-3.6-20091214.jar and poi-ooxml-3.6-20091214.jar to read .xlsx file. but i am getting following errors
The project was not built since its classpath is incomplete. Cannot find the class
file for java.lang.Iterable. Fix the classpath then try rebuilding this project.
This compilation unit indirectly references the missing type java.lang.Iterable
(typically some required class file is referencing a type outside the classpath)
how can i resolve it
here is the code that i have used
public class HomeAction extends DispatchAction {
     public ActionForward addpage(
                         ActionMapping mapping,
                         ActionForm form,
                         HttpServletRequest request,
                         HttpServletResponse response)
                         throws Exception {
                         String name = "C:/Documents and Settings/bharath/Desktop/Book1.xlsx";
           FileInputStream fis = null;
           try {
               Object workbook = null;
                fis = new FileInputStream(name);
                XSSFWorkbook wb = new XSSFWorkbook(fis);
                XSSFSheet sheet = (XSSFSheet) wb.getSheetAt(0);
                Iterator rows = sheet.rowIterator();
                int number=sheet.getLastRowNum();
                System.out.println(" number of rows"+ number);
                while (rows.hasNext())
                    XSSFRow row = ((XSSFRow) rows.next());
                    Iterator cells = row.cellIterator();
                    while(cells.hasNext())
                XSSFCell cell = (XSSFCell) cells.next();
                String Value=cell.getStringCellValue();
                System.out.println(Value);
           } catch (IOException e) {
                e.printStackTrace();
           } finally {
                if (fis != null) {
                     fis.close();
            return mapping.findForward("returnjsp");

Java.lang.NullPointerException in the code to read a properties file

I have written the following code to read a properties file...........

public Property(String fileName)
 try
 InputStream is = MyClassName.class.getClass().getClassLoader().getResourceAsStream(fileName);
 prop.load(is);
 is.close();
 catch (Exception ex)
 System.out.println("The Exception is: " + ex.getMessage());
 ex.printStackTrace();

But this code is giving java.lang.NullPointerException at prop.load(is) 
please help me....
regards
Brahmachaitanya

hi,
 If you are loading a resource (property) file from a jar file you can use
getResourceAsStream("com/test/test.properties").
 if the propery file is in outside of your jar file . you can use
Property portalProps = new Property ();
try {
 FileInputStream fileInputStream = new FileInputStream("<FilePath + FileName>");
 portalProps.load(fileInputStream);
 fileInputStream.close();
 } catch (IOException e) {
 //Log the error
refer the following link for more details
http://www.javaworld.com/javaworld/javaqa/2003-08/01-qa-0808-property.html

Prompt java to read in a file

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