InputStream中3个read方法的区别

3个read方法的区别

read()读取1个字节
read(byte[] b)将文本中的所有数据读取到b这个字节数组中
read(byte[] b, int off, int len)从流的第off个字节开始，读入长度为len的字节的数据

*****************read（）*****************

package com.xuzhiwen.io1;

import java.io.File;
import java.io.FileInputStream;

public class InputStreamTest {
    public static void main(String[] args) throws Exception {
        String s = File.separator;
        File file = new File("E:"+s+"filetest"+s+"11.txt");
        FileInputStream in = new FileInputStream(file);
        int i;
        while((i=in.read()) != -1){
            System.out.println((char)i);
        }
    }
}

11.TXT文件内容：

运行程序输出结果为：

*****************read(byte[] b)*****************

返回值为：实际读取的字节数

package com.xuzhiwen.io1;

import java.io.File;
import java.io.FileInputStream;

public class InputStreamTest {
    public static void main(String[] args) throws Exception {
        String s = File.separator;
        File file = new File("E:"+s+"filetest"+s+"11.txt");
        FileInputStream in = new FileInputStream(file);
        int len;
        byte b[] = new byte[1024];
        while((len = in.read(b)) != -1){
            System.out.println(new String(b));
        }
    }
}

运行结果如下：

 

*****************？*****************