网络编程之文件上传

文件上传

项目思路

• 客户端用文件输入流找到文件,再用输出流传给服务端

• 服务端用输入流接收数据,再用文件输出流保存到磁盘中

  ---

• 服务端接收完文件后,发信息给客户端告诉他接收完毕

• 客户端确认一下

---

注意事项

• accept是阻塞式监听

• scoket.shutdonwOutput():确认输出完毕,让其他人执行代码

• 文件输出流默认将文件输出到当前目录下

  ---

• 尽量一个问题对应一个捕获

• 如果一个捕获中同时有两行代码可能出问题,并且问题相同

• 一旦出错就不好知道是哪行代码出了问题

  ---

• 把异常打印出来,直接知道怎么回事

---

客户端

package com.li.changGe.fileUpload;


import java.io.*;
import java.net.InetAddress;
import java.net.Socket;

/**
 * 用文件输入流上传文件
 *
 * 输出完告诉服务端我结束了
 *
 * 确认机制
 */
public class Client {

  public static void main(String[] args) {
    new Client().upload();
  }

  public void upload() {

    InetAddress inetAddress = null;

    Socket socket = null;

    OutputStream outputStream = null;

    FileInputStream fileInputStream = null;

    InputStream inputStream = null;

    ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();

    try {
      inetAddress = InetAddress.getByName("127.0.0.1");

    } catch (Exception e) {
      System.out.println("请确认ip地址是否正确");
    }

    try {
      socket = new Socket(inetAddress, 8080);
    } catch (IOException e) {
      System.out.println("请注意ip地址和端口号");
    }

    try {
      outputStream = socket.getOutputStream();
    } catch (IOException e) {
      System.out.println("socket可能存在问题");
    }
//-------------------------------------------------------------------

    try {
      fileInputStream = new FileInputStream("E:\\JAVA\\JavaSE\\10网络编程\\李长歌.jpg");

    } catch (IOException e) {
      System.out.println("文件路径可能存在问题2");
    }

    byte[] bytes = new byte[1024];

    int length;

    try {
      while ((length = fileInputStream.read(bytes)) != -1) {
        outputStream.write(bytes, 0, length);
      }
    } catch (IOException e) {
      System.out.println("没有读取到文件1");
    }

    System.out.println("文件上传完成");
    try {
      /**
       * 关掉输出,
       * 
       * 告诉服务端我的业务暂时结束了,你可以执行自己的业务了
       */
      socket.shutdownOutput();
    } catch (IOException e) {
      System.out.println("输出关闭失败");
    }
//---------------------------------------------------------------

    try {
      inputStream = socket.getInputStream();

    } catch (IOException e) {
      System.out.println("创建输入流失败");
    }

    byte[] beefier = new byte[1024];

    try {

      /**
       * 尽量一个问题一个捕获
       *
       * 当两行代码都有可能出问题时,问题又一样
       * 一个捕获就不能直接知道是哪一行代码出问题
       */
      while((length = inputStream.read(beefier)) != -1){
        byteArrayOutputStream.write(beefier,0,length);
        System.out.println(byteArrayOutputStream.toString());
      }

    }catch (Exception e){
      /**
       * 把异常打印出来
       * 知道怎么回事
       */
      System.out.println("读取信息失败");
      e.printStackTrace();
    }


    if(byteArrayOutputStream != null){
      try {
        byteArrayOutputStream.close();
      }catch (Exception e){
        System.out.println("管道流关闭错误");
      }

    }


    if(inputStream != null){
      try {
        inputStream.close();
      }catch (Exception e){
        System.out.println("输入流关闭错误");
      }

    }

    if(fileInputStream != null){
      try {
        fileInputStream.close();
      }catch (Exception e){
        System.out.println("文件输入流关闭错误");
      }

    }

    if(outputStream != null){
      try {
        outputStream.close();
      }catch (Exception e){
        System.out.println("输出流关闭错误");
      }

    }

    if(socket != null){
      try {
        socket.close();
      }catch (Exception e){
        System.out.println("套接字关闭错误");
      }

    }

  }//upload

}

---

服务端

package com.li.changGe.fileUpload;

import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.nio.charset.StandardCharsets;

/**
 * 用文件输出流读取文件
 *
 * 接收完告诉客户端我结束了
 *
 * 确认机制
 *
 * 文件输出流默认输出到当前路径下
 */
public class Service {

  public static void main(String[] args) {
    new Service().download();
  }

  public void download(){

    ServerSocket serverSocket = null;

    InetAddress inetAddress = null;

    Socket socket = null;

    OutputStream outputStream = null;

    FileOutputStream fileOutputStream = null;

    InputStream inputStream = null;


    try {
      serverSocket = new ServerSocket(8080);

      /**
       * accept阻塞式监听
       */
      socket = serverSocket.accept();

      inputStream = socket.getInputStream();

      fileOutputStream = new FileOutputStream("E:\\JAVA\\JavaSE\\10网络编程\\LiChangGe.jpg");

      byte[] bytes = new byte[1024];

      int length;

      while ((length = inputStream.read(bytes)) != -1){
        fileOutputStream.write(bytes,0,length);
      }

      /**
       * 这里不用停顿
       * 接收完文件直接就给客户端发信息了
       */
      //socket.shutdownInput();

      outputStream = socket.getOutputStream();
      outputStream.write("文件接收完毕".getBytes(StandardCharsets.UTF_8));

    }catch (Exception e){
      System.out.println("请检查端口号,网络环境");
      e.printStackTrace();
    }finally {

      if (outputStream != null) {
        try {
          outputStream.close();
        } catch (Exception e) {
          System.out.println("输出流关闭错误");
        }

      }

      if (fileOutputStream != null) {
        try {
          fileOutputStream.close();
        } catch (Exception e) {
          System.out.println("文件输入流关闭错误");
        }

      }

      if (inputStream != null) {
        try {
          inputStream.close();
        } catch (Exception e) {
          System.out.println("输入流关闭错误");
        }

      }

      if (socket != null) {
        try {
          socket.close();
        } catch (Exception e) {
          System.out.println("套接字关闭错误");
        }

      }

    }//finally


  }

}