java基本io流的操作

1.将控制台输入的写入到txt文件中

package com.soulant.main;import java.io.BufferedReader;import java.io.BufferedWriter;import java.io.FileWriter;import java.io.IOException;import java.io.InputStreamReader;import java.io.PrintWriter;/*将控制台输入的字符-转化成字节-再转化为字符流写入文件注意事项: "E:\\JavaTest\\HelloWorld.txt" 而不是  "E:\JavaTest\HelloWorld.txt"      将字符串进行转义*/public class TestIo {    public static void main(String[] args)throws IOException {        BufferedReader in  = new BufferedReader(new InputStreamReader(System.in));        String s;        try {            while ((s = in.readLine()).length()!=0) {                System.out.println(s);                PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("E:\\JavaTest\\HelloWorld.txt")));                out.println(s);                System.out.println("写入");                out.close();            }        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }}

将txt文件里面的内容写入到另一个文件中

package com.soulant.main;import java.io.BufferedReader;import java.io.File;import java.io.FileNotFoundException;import java.io.FileReader;import java.io.FileWriter;import java.io.IOException;import java.io.PrintWriter;/* * 将一个txt文件里面的内容写入到另一个txt文件 *  */public class TestFile {    public static void main(String[] args) {        File filein,fileout;        BufferedReader bf = null;        PrintWriter pw = null;        filein = new File("E:\\JavaTest\\filein.txt");        fileout = new File("E:\\JavaTest\\fileout.txt");//如果没有就会自动创建        try {            bf = new BufferedReader(new FileReader(filein));            pw = new PrintWriter(fileout);//PrintWriter为打印流，也可以使用BufferedWriter.            String line = bf.readLine();            while (line!=null) {            pw.println(line);            line = bf.readLine();            }        } catch (Exception e) {            // TODO Auto-generated catch block            e.printStackTrace();        }finally{                try {                    if (bf!=null) {                    bf.close();                    bf = null;                    }                    if (pw!=null) {                        pw.close();                        pw = null;                        }                } catch (IOException e) {                    // TODO Auto-generated catch block                    e.printStackTrace();            }        }    }}