四个节点流

package lianxi1;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;

import org.junit.Test;

public class TestFileInputStream {
    @Test //要读取的文件一定要存在
   public void test1(){
    FileInputStream fis = null;
    try {
            File file1 = new File("d:\\io\\helloworld.txt");
            fis = new FileInputStream(file1);
            int b = fis.read();
            while(b!=-1){
                System.out.print((char)b);
                b = fis.read();
            }
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        finally{
            try {
                fis.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
    @Test
    // 要读取的文件一定要存在
    public void test2() {
        FileInputStream fis = null;
        try {
            File file1 = new File("d:\\io\\helloworld.txt");
            fis = new FileInputStream(file1);
            byte[] b = new byte[6];
            int len;
//            int len = fis.read(b);
//            while (len != -1) {
//                for(int i=0;i<len;i++){
//                   System.out.print((char)b[i]);
//                }
//                len = fis.read(b);
//            }
            while ((len=fis.read(b))!= -1) {  //注意  b是存储数据的缓冲器，len是返回读入缓冲区的字节总数
                                              //所以len<=b.length
                for(int i=0;i<len;i++){   //是len，不是b.length
                   System.out.print((char)b[i]);
                }
            
            }
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
            try {
                fis.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }

    }
}
package lianxi1;

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

import org.junit.Test;

public class TestFileOutputStream {
@Test //要写入的文件不一定要存在,不存在可以被创建，存在的话内容会被覆盖
    public void test1(){
    FileOutputStream fos = null;
       try {
        File file1 = new File("GoodMood");
        fos = new FileOutputStream(file1);
        fos.write(new String("Have a good night!").getBytes());
    } catch (Exception e) {
        e.printStackTrace();
    }
    finally{
        try {
            fos.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }    
}
@Test //从一个文件中读入数据，写入另一个文件
    public void test2(){
    FileInputStream fis = null;
    FileOutputStream fos = null;
    try{
        File file1 = new File("d:/io/helloworld.txt");
        File file2 = new File("GoodMood");
        fis = new FileInputStream(file2);
        fos = new FileOutputStream(file1);
        int len;
        byte[] b = new byte[4];
        while((len = fis.read(b))!=-1){
                fos.write(b, 0, len);    
        }
    }catch(Exception ex){ ex.printStackTrace();}
    finally{
        if(fis!=null){
            try {
                fis.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        if(fos!=null){
            try {
                fos.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
}
}