IO:InputStream

InputStream类（java.io.InputStream）

public abstract class InputStream extends Object implements Closeable

构造方法：public InputStream()

普通方法：

public abstract int read()throws IOException	依次读取单个字节数据，如果没有内容则返回-1
public int read(byte[] b) throws IOException	读出输入流的数据，写入字节数组，返回实际读取到的长度，如果没有内容则返回-1
public int read(byte[] b, int off, int len) throws IOException	读出输入流指定长度的数据，写入字节数组的指定位置，返回实际读取到的长度，如果没有内容则返回-1。但是当指定长度为0时返回0；
public void close()throws IOException	关闭数据流

 

 

FileInputStream(java.io.FileInputStream)

public class FileInputStream extends InputStream

构造方法：

public FileInputStream(File file) throws FileNotFoundException	从文件创建输入流（File类）
public FileInputStream(String name) throws FileNotFoundException	从文件创建输入流（String类）

 

实例：

test1.txt的内容	0123456789abcdefghijklmn
Test2.txt的内容	01234

 

package wiki.jjcc.test.ips;

 

import java.io.File;

import java.io.FileInputStream;

import java.io.InputStream;

 

public
class Test1 {

    public
static
void main(String[] args) throws Exception {

        String s = File.separator;

        File file1 = new File("d:"+s+"temp"+s+"test1.txt");

        File file2 = new File("d:"+s+"temp"+s+"test2.txt");

        InputStream input = new FileInputStream(file1);

        byte[] b1 = new
byte[10];

        byte[] b2 = new
byte[10];

        int
num1 = input.read(b1,3,6);

        int
num2 = input.read(b2,3,6);

        System.out.println(num1);

        System.out.println("["+new String(b1)+"]");

        System.out.println(num2);

        System.out.println("["+new String(b2)+"]");

        input.close();

    }

}

 

package wiki.jjcc.test.ips;

 

import java.io.File;

import java.io.FileInputStream;

import java.io.InputStream;

 

public
class Test1 {

    public
static
void main(String[] args) throws Exception {

        String s = File.separator;

        File file1 = new File("d:"+s+"temp"+s+"test1.txt");

        File file2 = new File("d:"+s+"temp"+s+"test2.txt");

        InputStream input = new FileInputStream(file2);

        byte[] b1 = new
byte[10];

        byte[] b2 = new
byte[10];

        int
num1 = input.read(b1,3,6);

        int
num2 = input.read(b2,3,6);

        System.out.println(num1);

        System.out.println("["+new String(b1)+"]");

        System.out.println(num2);

        System.out.println("["+new String(b2)+"]");

        input.close();

    }

}

package wiki.jjcc.test.ips;

 

import java.io.File;

import java.io.FileInputStream;

import java.io.InputStream;

 

public
class Test1 {

    public
static
void main(String[] args) throws Exception {

        String s = File.separator;

        File file = new File("d:"+s+"temp"+s+"test1.txt");

        InputStream input = new FileInputStream(file);

        byte[] b = new
byte[30];

        int
foot = 0;

        int
temp = 0;

        while((temp=input.read())!=-1){

            b[foot++]=(byte)temp;

        }

        System.out.println(temp);

        System.out.println("["+new String(b)+"]");

        input.close();

    }

}