缓冲流原理

缓冲流原理

字节缓冲输出流

package com.mujiachao.huanchongliu;

import java.io.BufferedOutputStream;
import java.io.FileOutputStream;
import java.io.IOException;

public class BufferOut {
    public static void main(String[] args) throws IOException {
        FileOutputStream fileOutputStream = new FileOutputStream("F:\\电影\\111\\F.txt");
        BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(fileOutputStream);
        bufferedOutputStream.write("我把数据通过字节缓冲输出流写入硬盘".getBytes());
        bufferedOutputStream.close();
    }
}

字节缓冲输入流

字节缓冲输入流

package com.mujiachao.huanchongliu;

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

public class BufferIn {
    public static void main(String[] args) throws IOException {
        FileInputStream fileInputStream = new FileInputStream("F:\\电影\\111\\F.txt");
//        BufferedInputStream bufferedInputStream = new BufferedInputStream(fileInputStream);
        BufferedInputStream bufferedInputStream = new BufferedInputStream(fileInputStream,2048);
//        int len=0;
//        while ((len=bufferedInputStream.read())!=-1){
//            System.out.println(len);
//        }
        int len=0;
        byte[] bytes=new byte[2048];
        while ((len=bufferedInputStream.read(bytes))!=-1){
            System.out.println(new String(bytes));
        }
        bufferedInputStream.close();
    }
}

缓冲流效率测试

package com.mujiachao.huanchongliu;

import java.io.*;

public class CopyCeSu {
    public static void main(String[] args) throws IOException {
        long l = System.currentTimeMillis();
        FileOutputStream fileOutputStream = new FileOutputStream("F:\\电影\\111\\JavaEE开发的颠覆者 Spring Boot实战  完整版.pdf");
        FileInputStream fileInputStream = new FileInputStream("C:\\Users\\Administrator\\Desktop\\JavaEE开发的颠覆者 Spring Boot实战  完整版.pdf");
        BufferedInputStream bufferedInputStream = new BufferedInputStream(fileInputStream);
        BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(fileOutputStream);
        int len=0;
        byte[] bytes=new byte[102400];
        while ((len=bufferedInputStream.read(bytes))!=-1){
            bufferedOutputStream.write(len);
        }
        bufferedOutputStream.close();
        bufferedInputStream.close();
        System.out.println(System.currentTimeMillis()-l+"毫秒");
    }

}

字符缓冲输出流 bufferedWriter.newLine();换行

符缓冲输出流

使用步骤

package com.mujiachao.huanchongliu;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;

public class BufferWriter {
    public static void main(String[] args) throws IOException {
        FileWriter fileWriter = new FileWriter("F:\\电影\\111\\a.txt");
        BufferedWriter bufferedWriter = new BufferedWriter(fileWriter);
        for (int i = 0; i < 10; i++) {
            bufferedWriter.write("字符缓冲输出流");
            bufferedWriter.newLine();
        }
        bufferedWriter.close();
    }
}

字符缓冲输入流 bufferedReader.readLine() 读取一行

字符缓冲输入流

步骤

package com.mujiachao.huanchongliu;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class BufferReader {
    public static void main(String[] args) throws IOException {
        BufferedReader bufferedReader = new BufferedReader(new FileReader("F:\\电影\\111\\a.txt"));
        String s;
        while ((s=bufferedReader.readLine())!=null){
            System.out.println(s);
        }
        bufferedReader.close();
    }
}

练习，对文本内容进行排序

对文本内容进行排序

package com.mujiachao.huanchongliu;

import java.io.*;
import java.util.HashMap;

public class LianXi {
    public static void main(String[] args) throws IOException {
        HashMap<String, String> objectObjectHashMap = new HashMap<>();
        FileReader fileReader = new FileReader("F:\\电影\\111\\in.txt");
        FileWriter fileWriter = new FileWriter("F:\\电影\\111\\out.txt");
        BufferedReader bufferedReader = new BufferedReader(fileReader);
        BufferedWriter bufferedWriter = new BufferedWriter(fileWriter);
        String s;
        while ((s=bufferedReader.readLine())!=null){
            String[] split = s.split("\\.");
            objectObjectHashMap.put(split[0],split[1]);
        }
        for (String key:objectObjectHashMap.keySet()) {
            s=key+"."+objectObjectHashMap.get(key);
            bufferedWriter.write(s);
            bufferedWriter.newLine();
        }
        bufferedWriter.close();
        bufferedReader.close();
    }
}