java 利用TCP上传文件

从客户端上传到服务器端，其实本质上也就是复制！

package july76net;

//上传文件(文本)

import java.io.BufferedReader;

import java.io.FileReader;

import java.io.InputStreamReader;

import java.io.PrintWriter;

import java.net.Socket;

public class Demo14 {

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

Socket s = new Socket("localhost",12362);

BufferedReader br  = new BufferedReader(new FileReader("E:/你好.txt"));

PrintWriter pw = new PrintWriter(s.getOutputStream(),true);

String line;

while((line = br.readLine()) != null){

pw.println(line);

}

s.shutdownOutput();//阻塞式方法的应对，否则会一直等待！

BufferedReader br2 = new BufferedReader(new InputStreamReader(s.getInputStream()));

String str = br2.readLine();//服务器端反馈的数据

System.out.println(str);

br.close();

s.close();

}

}

服务器端

package july76net;

import java.io.BufferedReader;

import java.io.FileWriter;

import java.io.InputStreamReader;

import java.io.PrintWriter;

import java.net.ServerSocket;

import java.net.Socket;

public class Demo15 {

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

ServerSocket ss = new ServerSocket(12362);

Socket s = ss.accept();

String ip = s.getInetAddress().getHostAddress();

System.out.println(ip+".....connected!");

BufferedReader br = new BufferedReader(new InputStreamReader(s.getInputStream()));

PrintWriter pw = new PrintWriter(new FileWriter("E:/你好2.txt"),true);//建议打印时都用打印流

String line;

while((line = br.readLine()) != null){

pw.println(line);//不可以写成是write();

}

PrintWriter out = new PrintWriter(s.getOutputStream(),true);

out.println("上传成功！");

s.close();

ss.close();

}

}

上传图片（注意图片是2进制文件，必须是字节流，否则读取不出来！）；

客户端

package july76net;

import java.io.FileInputStream;

import java.io.InputStream;

import java.io.OutputStream;

import java.net.Socket;

public class Demo16 {

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

Socket s = new Socket("localhost",10256);

FileInputStream fis = new FileInputStream("E:/DSC_2451.jpg");

OutputStream os = s.getOutputStream();

byte []buf = new byte[1024];

int len;

while((len = fis.read(buf)) != -1){

os.write(buf);

}

s.shutdownOutput();

InputStream in = s.getInputStream();

byte []b = new byte[1024];

int i = in.read(b);

System.out.println(new String(b,0,i));

fis.close();

s.close();

}

}

服务器端

package july76net;

import java.io.FileOutputStream;

import java.io.InputStream;

import java.io.OutputStream;

import java.net.ServerSocket;

import java.net.Socket;

public class Demo17 {

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

ServerSocket ss = new ServerSocket(10256);

Socket s = ss.accept();

String ip = s.getInetAddress().getHostAddress();

System.out.println(ip+".........connected");

InputStream is = s.getInputStream();

FileOutputStream fos = new FileOutputStream("E:/我的照片0.jpg");

byte []b = new byte[1024];

int len;

while((len = is.read(b)) != -1){

fos.write(b);

}

OutputStream os = s.getOutputStream();

os.write("上传成功！".getBytes());

s.close();

ss.close();

}

}

我的总结：

对于网络编程而言，重要的是理解其步骤，按照步骤的需要，一步步搭建根基！

客户端和服务端需要交互，那么就要构建相对应的流，供其输入和输出！

对于阻塞式方法，一定要注意，提供停止标签！

对于PrintWriter ,记得用println而不是write;不要忘了加上true，自动刷新！