打印流(PrintWriter ）

PrintWriter

package cn.lijun.demo1;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.PrintWriter;

// 打印流  PrintStream    PrintWriter

//  特点  不负责数据源  只负责数据目的    不会抛IOException     可能会抛出其他异常

public class Demo1PrintWrite {

    public static void main(String[] args) throws Exception {

        fun4();

    }

    //打印流可以开启自动刷新功能   输出的数据必须是流对象  Outputem  Writer

        //  必须调用print 方法

        public static void fun4() throws FileNotFoundException{

            FileOutputStream fos = new FileOutputStream("c:\\ll.txt");

            PrintWriter pr = new PrintWriter(fos,true);

            pr.print("zhang");

            pr.print("zhang");

            pr.print("zhang");

            pr.close();

        }

    //打印流输出目的  是流对象

    public static void fun3() throws FileNotFoundException{

        PrintWriter p= new PrintWriter("c:\\6.txt");

        PrintWriter p1= new PrintWriter(p);

        p1.println("打印流");

        p1.close();

    }

    //打印流 输出目的 String 文件名

    public static void fun2() throws FileNotFoundException{

        PrintWriter p = new PrintWriter("c:\\3.txt");

        p.println(333);

        p.println(333);

        p.close();

    }

    /*向File对象的数据目的写入数据*/

    public static void fun() throws Exception{

        File file =  new File("c:\\2.txt");

        PrintWriter p = new PrintWriter(file);

        p.print(true);

        p.print(100);

        p.close();

    }

}

//打印流复制文件

package cn.lijun.demo1;

import java.io.BufferedReader;

import java.io.FileNotFoundException;

import java.io.FileReader;

import java.io.FileWriter;

import java.io.IOException;

import java.io.PrintWriter;

public class Demo2PrintReder {

    public static void main(String[] args) throws IOException {

        BufferedReader bf = new BufferedReader(new FileReader("c:\\ll.txt"));

        PrintWriter p= new PrintWriter(new FileWriter("d:\\ll.txt"),true);

        String line= null;

        while((line=bf.readLine())!=null){

            p.print(line);

        }

        p.close();

        bf.close();

    }

}