1.缓冲流

package Io;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
public class BufferDemo {
    public static void main(String[] args) throws IOException {
//      //缓冲输入流
//      BufferedReader br = new BufferedReader(new FileReader("test.txt"));
//      String str=null;
//      while((str=br.readLine()) != null){
//          System.out.println(str);
//      }
//      br.close();
        //缓冲输入流
        BufferedReader br = new BufferedReader(new FileReader("test.txt"));
        //缓冲输出流  读取出的内容写入新文件
        BufferedWriter bw = new BufferedWriter(new FileWriter("new.txt"));
        String str=null;
        while((str=br.readLine()) != null){//一次读取一行
            bw.write(str);//读取出一行写入新文件
            bw.newLine();//实现换行
            bw.flush();
        }
        br.close();
        bw.close();
    }
}

2.打印输出流

package Io;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Date;
public class PrintDemo {
    public static void main(String[] args) throws IOException {
//      打印输出流
        PrintWriter pw = new PrintWriter(new FileWriter("log.txt"));
        pw.print(false);
        pw.println("java");
        Date time = new Date();
        pw.println("在："+time+"对log进行了操作");
        pw.flush();
        pw.close();
    }
}