Java IO流处理

Java IO流处理

Java IO流主要分为字符流（Reader、Writer）和字节流（InputStream、OutputSrteam）。
下图是所有IO流的类：

以下介绍常用的几种IO流处理：
1、BufferedReader

BufferedReaderTest

package Reader;

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

public class BufferedReaderTest {

    private static void read(String path){
        File file = new File(path);
        FileReader fr = null;
        BufferedReader br = null;

        try {
            fr = new FileReader(file);
            br = new BufferedReader(fr);
            String line = null;
            while((line = br.readLine())!=null){
                System.out.println(line);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }finally{
            try {
                br.close();
                fr.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    public static void main(String[] args) {
        read("file");
    }

}

2、BufferedWriter

BufferedWriterTest

package Writer;

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

public class BufferedWriterTest {

    private static void write(String path,String text){
        FileWriter fw = null;
        BufferedWriter bw = null;

        try {
            fw = new FileWriter(path);
            bw = new BufferedWriter(fw);
            bw.write(text+"\n");
        } catch (IOException e) {
            e.printStackTrace();
        }finally{
            try {
                bw.close();
                fw.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    public static void main(String[] args) {

        Scanner input = new Scanner(System.in);
        System.out.println("请输入，以回车键结束：");
        write("file",input.nextLine());
        input.close();
    }
}

3、BufferedInputStream、BufferedOutputStream

BufferedInputStreamTest

package Stream;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class BufferedInputStreamTest {

    private static void input(String path){
        FileInputStream fis = null;
        BufferedInputStream bs = null;

        FileOutputStream fos = null;
        BufferedOutputStream bo = null;

        byte[] buffer = new byte[256];

        try {
            fis = new FileInputStream(path);
            bs = new BufferedInputStream(fis);

            fos = new FileOutputStream(new File("file1"));
            bo = new BufferedOutputStream(fos);

            int len = 0;
            while((len = bs.read(buffer))!= -1){
                bo.write(buffer, 0, len);
                bo.flush();
            }
            System.out.println("复制完成！");
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }finally{
            try {
                fis.close();
                bs.close();
                fos.close();
                bo.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    public static void main(String[] args) {
        input("file");
    }
}

4、ObjectInputStream

ObjectStreamTest

package Reader;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;

public class ObjectStreamTest {

    private static void write(String path){

        FileInputStream fis = null;
        ObjectInputStream ois = null;
        FileOutputStream fos = null;
        ObjectOutputStream oos = null;

        try {
            fos = new FileOutputStream(path);
            oos = new ObjectOutputStream(fos);
            oos.writeObject(new Book("Java","xc"));
            oos.writeObject(new Book("C","xc"));

            fis = new FileInputStream(path);
            ois = new ObjectInputStream(fis);
            for (int i = 0; i < 2; i++) {
                System.out.println(ois.readObject());
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }finally{
            try {
                oos.close();
                fos.close();
                ois.close();
                fis.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    public static void main(String[] args) {
        write("file");
    }
}

Book.java

package Reader;

import java.io.Serializable;

public class Book implements Serializable{

    private String name;
    private String writer;

    public Book(String name,String writer){
        this.name = name;
        this.writer = writer;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getWriter() {
        return writer;
    }

    public void setWriter(String writer) {
        this.writer = writer;
    }

    public String toString(){
        return "Book:{name:"+name+",writer:"+writer+"}";
    }
}

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