【JAVA】IO详解

 1 public static String read(String filename) throws Exception {  
 2 
 3 　　　　       BufferedReader br = new BufferedReader(new FileReader(filename));  
 4 
 5 　　　　       String s;  
 6 
 7 　　　　       StringBuffer sb = new StringBuffer(); 　　　　　　while ((s = br.readLine()) != null) {  
 8 
 9 　　　　            sb.append(s + "\n");  
10 
11 　　　　       }  
12 
13 　　　　       br.close();  
14 
15 　　　　　　return sb.toString();  
16 
17 　　　　   } 

 1 import java.io.*;
 2 public class SRDemo
 3 {
 4   public static void main(String args[]) throws IOException
 5   {
 6     String s1 = "For outsiders\nthe Software engineer\nlooks housed\nin a golden cage";
 7     StringReader sreader = new StringReader(s1);
 8     BufferedReader breader = new BufferedReader(sreader);
 9         
10     String s2;
11     while( ( s2 = breader.readLine() ) != null)
12     {
13       System.out.println(s2);
14     }
15     breader.close();  sreader.close();
16   }
17 }

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;

/**
 * 一个非常实用的文件操作类 . 2012-12-19
 * 
 * @author Bruce Eckel , edited by erqing
 * 
 */
public class TextFile extends ArrayList<String> {

    private static final long serialVersionUID = -1942855619975438512L;

    // Read a file as a String
    public static String read(String filename) {
        StringBuilder sb = new StringBuilder();
        try {
            BufferedReader in = new BufferedReader(new FileReader(new File(
                    filename).getAbsoluteFile()));
            String s;
            try {
                while ((s = in.readLine()) != null) {
                    sb.append(s);
                    sb.append("\n");
                }
            } finally {
                in.close();
            }

        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        return sb.toString();
    }

    // Write a single file in one method call
    public static void write(String fileName, String text) {
        try {
            PrintWriter out = new PrintWriter(
                    new File(fileName).getAbsoluteFile());
            try {
                out.print(text);
            } finally {
                out.close();
            }
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    // Read a file,spilt by any regular expression
    public TextFile(String fileName, String splitter) {
        super(Arrays.asList(read(fileName).split(splitter)));
        if (get(0).equals(""))
            remove(0);
    }

    // Normally read by lines
    public TextFile(String fileName) {
        this(fileName, "\n");
    }

    public void write(String fileName) {
        try {
            PrintWriter out = new PrintWriter(
                    new File(fileName).getAbsoluteFile());
            try {
                for (String item : this)
                    out.println(item);
            } finally {
                out.close();
            }

        } catch (IOException e) {
            throw new RuntimeException(e);
        }

    }

    // test,I have generated a file named data.d at the root
    public static void main(String[] args) {

        /* read() test */
        System.out.println(read("data.d")); // testing is OK!

        /* write() test */
        write("out.d", "helloworld\negg"); // testing is OK!

        /* constractor test */
        TextFile tf = new TextFile("data.d"); // testing is OK!

    }

}

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;

/**
 * to read the binary file
 * 
 * @author erqing
 * 
 */
public class BinaryFile {

    /* the parametre is a file */
    public static byte[] read(File file) throws IOException {
        BufferedInputStream bf = new BufferedInputStream(new FileInputStream(
                file));
        try {
            byte[] data = new byte[bf.available()];
            bf.read(data);
            return data;
        } finally {
            bf.close();
        }
    }

    /* the param is the path of a file */
    public static byte[] read(String file) throws IOException {
        return read(new File(file).getAbsoluteFile());
    }
}