Java IO流

1. 流的分类

• 按操作数据单位不同分为：字节流(8 bit)，字符流(16 bit)
• 按数据流的流向不同分为：输入流，输出流
• 按流的角色的不同分为：节点流，处理流

2. 示例代码

package com.windy.io;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

import org.junit.Test;

public class IOTest {

    @Test
    public void FileStreamTest(){
        
            File f1 = new File("001.jpg");
            File f2 = new File("001-copy.jpg");
            
            FileInputStream fis = null;
            FileOutputStream fos = null;
            
            try {
                    fis = new FileInputStream(f1);
                    fos = new FileOutputStream(f2);
                    
                    byte [] b = new byte[512];
                    int len = 0; 
                    
                    while((len = fis.read(b)) != -1){
                            fos.write(b, 0, len);
                    }
                    
                    
            } catch (Exception e) {
                    e.printStackTrace();
            }finally{
                
                    if(fis != null){
                        try {
                            fis.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }                        
                    }
                    if(fos != null){
                        try {
                            fos.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }                        
                    }
            }
        
    }
    
    @Test
    public void FileStringTest(){
            File f1 = new File("001.txt");
            File f2 = new File("001-copy.txt");
            
            FileReader fis = null;
            FileWriter fos = null;
            
            try {
                    fis = new FileReader (f1);
                    fos = new FileWriter (f2);
                    
                    char [] b = new char[10];
                    int len = 0; 
                    
                    while((len = fis.read(b)) != -1){

                            fos.write(b, 0, len);
                    }
                    
                    
            } catch (Exception e) {
                    e.printStackTrace();
            }finally{
                
                    if(fis != null){
                        try {
                            fis.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }                        
                    }
                    if(fos != null){
                        try {
                            fos.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }                        
                    }
            }
        }
    
    @Test
    public void BufferTest(){
        File f1 = new File("001.txt");
        File f2 = new File("001-copy.txt");
        
        FileReader fis = null;
        FileWriter fos = null;
        
        try {
                fis = new FileReader (f1);
                fos = new FileWriter (f2);
                
                char [] b = new char[10];        
                int len = 0;  
                
                while((len = fis.read(b)) != -1){

                        fos.write(b, 0, len);
                }
                
                
        } catch (Exception e) {
                e.printStackTrace();
        }finally{
            
                if(fis != null){
                    try {
                        fis.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }                        
                }
                if(fos != null){
                    try {
                        fos.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }                        
                }
        }
        
        
    }
    
}