file2String faster code

What will be faster file2String ?

this :

or :

Thank you!

or this:

Thank you
Sharon

Have you tried to profile any of them?

I'd be interested to hear where you got the code for the last example. It is almost correct, but actually quite crazy.

In general:
Buffered streams will be better.
StringBuffers will be better.
Reading into a buffer rather than per character will be better.
Readers and Writers will be better for character data.

You may also like to like at the NIO classes.

Are you trying to solve a problem, just playing, design a component or have some other aim?

Originally posted by David O'Meara:
It is almost correct, but actually quite crazy.

I take that back, it is a variable with the name 'L', not a number 'one'. Calling it 'len' or 'length' would cause less confusion.

Originally posted by Sharon whipple:
What will be faster file2String ?

this :

int c; while ( ( c = file.read() ) != -1 ) textBuffer.append( (char) c );
or :
BufferedReader br = new BufferedReader(isr); String line=br.readLine(); result=line; while (line!=null) { line=br.readLine(); if (line==null) { } else { result=result+"\n"+line; }
Thank you!

These seem like hard work. How about

Results :
test0 : Runs: 241 iterations ,avarage milis = 246
test1 : Runs: 249 iterations ,avarage milis = 118
test2 : Runs: 269 iterations ,avarage milis = 5
test3 : Runs: 241 iterations ,avarage milis = 2

TestClass :

import java.io.*;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Random;
 
public class Tester {
 
    private static final String filePath = "c:\\bigFile.txt";
    //private static final String filePath = "c:\\bigfileNewLine.txt";
 
    private static final int numOfMethods = 4;
   private static final int numOfIter = 1000;
    public Tester() throws NoSuchMethodException {
        System.out.println("Tester.Tester");
 
        int[] milisArr = new int [numOfMethods];
        int[] actualRun = new int [numOfMethods];
 
        Random rnd = new Random(System.currentTimeMillis());
        Long startMs = 0l, endMs = 0l;
        Method[] method = new Method[numOfMethods];
        for (int i = 0; i < numOfMethods; i++)
            method[i] = this.getClass().getMethod("test" + i);
 
        int testCount = 0;
        while (testCount++ < numOfIter) {
            int testMethod = rnd.nextInt(numOfMethods);
            Method m = method[testMethod];
            try {
                System.gc();
                startMs = System.currentTimeMillis();
                String retval = (String) m.invoke(null);
                endMs = System.currentTimeMillis();
                
            } catch (IllegalAccessException e) {
                e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
            } catch (InvocationTargetException e) {
                e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
            }
            milisArr[testMethod] += (endMs - startMs);
            actualRun[testMethod]++;
            System.out.println("Test name: " + m.getName() + " testCount=" + testCount + " Of " + numOfIter + " iteration, Total time :" + (endMs - startMs) / 1000.0 + " seconds");
        }
 
        System.out.println("Test Summery :");
        for (int i = 0; i < numOfMethods; i++)
            System.out.println("test" + i + " :  Runs: " + actualRun[i] + " iterations ,avarage milis = " + milisArr[i]/numOfIter);
 
    }

public static String test0() throws IOException {
        InputStream file = getInputStream();
        StringBuffer textBuffer = new StringBuffer();
        int c;
        while ((c = file.read()) != -1)
            textBuffer.append((char) c);

file.close();
        return textBuffer.toString();
    }
 
    public static String test1() throws IOException {
        Reader reader = new FileReader(new File(filePath));
        BufferedReader br = new BufferedReader(reader);
        String line = br.readLine();
        String result = line;
        while (line != null) {
            line = br.readLine();
            if (line == null) {
            } else {
                result = result + "\n" + line;
            }
        }
        br.close();
        reader.close();
        return result;
    }

public static String test2() throws IOException {
        byte[] buf = new byte[1024];
        int l;
 
        InputStream is = getInputStream();
        StringBuffer tmpBuf = new StringBuffer();
        while ((l = is.read(buf)) != -1) {
            tmpBuf.append(new String(buf, 0, l));
        }
 
        is.close();
        return tmpBuf.toString();
    }
 
    public static String test3() throws IOException {
        File source = new File(filePath);
        final DataInputStream dis = new DataInputStream(new BufferedInputStream(new FileInputStream(source)));
        final byte[] buffer = new byte[(int) source.length()];
        dis.readFully(buffer);
        dis.close();
        return new String(buffer, "UTF-8");
    }
 
    private static InputStream getInputStream() {
        try {
            return new FileInputStream(filePath);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            return null;
        }
    }
 
    public static void main(String[] args) {
        try {
            new Tester();
        } catch (NoSuchMethodException e) {
            e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
        }
    }
}

Wow. That's quite a difference.