Java TCP 上传图片

TCP上传图片

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;

class PicClient
{
    public static void main(String[] args) throws Exception
    {
        Socket s = new Socket("192.168.23.27",10007);

        FileInputStream fis = new FileInputStream("2.jpg");

        OutputStream out = s.getOutputStream();

        byte[] buf = new byte[1024];

        int len = 0;

        while ((len = fis.read(buf))!=-1)
        {
            out.write(buf,0,len);
        }

        //告诉服务端数据已写完
        s.shutdownOutput();

        InputStream in = s.getInputStream();

        byte[] bufIn = new byte[1024];

        int num = in.read(bufIn);

        System.out.println(new String(bufIn,0,num));

        fis.close();

        s.close();
    }
}
class PicServer
{
    public static void main(String[] args) throws Exception
    {

        ServerSocket ss = new ServerSocket(10007);

        Socket s = ss.accept();

        InputStream in = s.getInputStream();

        FileOutputStream fos = new FileOutputStream("server.jpg");

        byte[] buf = new byte[1024];

        int len = 0;

        while ((len=in.read(buf))!=-1)
        {
            fos.write(buf,0,len);
        }

        OutputStream out = s.getOutputStream();

        out.write("上传成功".getBytes());

        fos.close();

        s.close();

        ss.close();
    }
}
public class TcpDemo3 {
    public static void main(String[] args) {

    }
}

19.gif

服务端上传图片的局限性
当A客户端连接上以后，被服务端获取到。服务端执行具体流程。这时B客户端连接，只有等待。因为服务端还没有处理完A客户端的请求，还有循环回来执行下次accept方法。所以暂时获取不到B客户端对象。
那么为了可以让多个客户端同时并发访问服务端。

服务端最好就是将每个客户端封装到一个单独的线程中，这样，就可以同时处理多个客户端请求。如何定义线程呢？只要明确了每一个客户端要在服务端执行的代码即可。将该代码存入run方法中。

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;

class PicClient0
{
    public static void main(String[] args) throws Exception
    {
        Socket s = new Socket("192.168.22.42",10008);

        FileInputStream fis = new FileInputStream("2.jpg");

        OutputStream out = s.getOutputStream();

        byte[] buf = new byte[1024];

        int len = 0;

        while ((len = fis.read(buf))!=-1)
        {
            out.write(buf,0,len);
        }

        //告诉服务端数据已写完
        s.shutdownOutput();

        InputStream in = s.getInputStream();

        byte[] bufIn = new byte[1024];

        int num = in.read(bufIn);

        System.out.println(new String(bufIn,0,num));

        fis.close();

        s.close();
    }
}
class PicThread implements Runnable
{
    private Socket s;
    PicThread(Socket s)
    {
        this.s = s;
    }
    public void run()
    {
        String ip = s.getInetAddress().getHostAddress();
        try
        {
            System.out.println(ip+"......connected");
            InputStream in = s.getInputStream();
            FileOutputStream fos = new FileOutputStream("server.bmp");
            byte[] buf = new byte[1024];
            int len = 0;
            while ((len = in.read(buf))!=-1)
            {
                fos.write(buf,0,len);
            }
            OutputStream out = s.getOutputStream();

            out.write("上传成功".getBytes());

            fos.close();

            s.close();
        }
        catch (Exception e)
        {
            throw new RuntimeException(ip+"上传失败");
        }
    }
}
class PicServer0
{
    public static void main(String[] args) throws Exception
    {
        ServerSocket ss = new ServerSocket(10008);

        while (true)
        {
            Socket s = ss.accept();

            new Thread(new PicThread(s)).start();


        }
    }
}
public class TcpDemo4 {
}

20.gif

避免图片名称被覆盖

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

class PicClient0
{
    public static void main(String[] args) throws Exception
    {
        Socket s = new Socket("192.168.22.42",10008);

        FileInputStream fis = new FileInputStream("2.jpg");

        OutputStream out = s.getOutputStream();

        byte[] buf = new byte[1024];

        int len = 0;

        while ((len = fis.read(buf))!=-1)
        {
            out.write(buf,0,len);
        }

        //告诉服务端数据已写完
        s.shutdownOutput();

        InputStream in = s.getInputStream();

        byte[] bufIn = new byte[1024];

        int num = in.read(bufIn);

        System.out.println(new String(bufIn,0,num));

        fis.close();

        s.close();
    }
}
class PicThread implements Runnable
{
    private Socket s;
    PicThread(Socket s)
    {
        this.s = s;
    }
    public void run()
    {
        int count = 1;
        String ip = s.getInetAddress().getHostAddress();
        try
        {
            System.out.println(ip+"......connected");
            InputStream in = s.getInputStream();
            File file = new File(ip+"("+(count)+")"+".jpg");
            while (file.exists())
                file = new File(ip+"("+(count++)+")"+".jpg");
            FileOutputStream fos = new FileOutputStream(file);
            byte[] buf = new byte[1024];
            int len = 0;
            while ((len = in.read(buf))!=-1)
            {
                fos.write(buf,0,len);
            }
            OutputStream out = s.getOutputStream();

            out.write("上传成功".getBytes());

            fos.close();

            s.close();
        }
        catch (Exception e)
        {
            throw new RuntimeException(ip+"上传失败");
        }
    }
}
class PicServer0
{
    public static void main(String[] args) throws Exception
    {
        ServerSocket ss = new ServerSocket(10008);

        while (true)
        {
            Socket s = ss.accept();

            new Thread(new PicThread(s)).start();


        }
    }
}
public class TcpDemo4 {
}

21.gif

通过主函数传值形式上传图片

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

class PicClient0
{
    public static void main(String[] args) throws Exception
    {
        if(args.length!=1)
        {
            System.out.println("请选择一个jpg格式的图片");
            return;
        }
        File file = new File(args[0]);
        if (!(file.exists() && file.isFile()))
        {
            System.out.println("该文件有问题，要么不存在，要么不是文件");
            return;
        }
        if (!file.getName().endsWith(".jpg"))
        {
            System.out.println("图片格式错误,请重新选择");
            return;
        }
        if (file.length()>1024*1024*5)
        {
            System.out.println("文件过大，没安好心");
            return;
        }

        Socket s = new Socket("192.168.22.42",10008);

        FileInputStream fis = new FileInputStream("2.jpg");

        OutputStream out = s.getOutputStream();

        byte[] buf = new byte[1024];

        int len = 0;

        while ((len = fis.read(buf))!=-1)
        {
            out.write(buf,0,len);
        }

        //告诉服务端数据已写完
        s.shutdownOutput();

        InputStream in = s.getInputStream();

        byte[] bufIn = new byte[1024];

        int num = in.read(bufIn);

        System.out.println(new String(bufIn,0,num));

        fis.close();

        s.close();
    }
}
class PicThread implements Runnable
{
    private Socket s;
    PicThread(Socket s)
    {
        this.s = s;
    }
    public void run()
    {
        int count = 1;
        String ip = s.getInetAddress().getHostAddress();
        try
        {
            System.out.println(ip+"......connected");
            InputStream in = s.getInputStream();
            File file = new File(ip+"("+(count)+")"+".jpg");
            while (file.exists())
                file = new File(ip+"("+(count++)+")"+".jpg");
            FileOutputStream fos = new FileOutputStream(file);
            byte[] buf = new byte[1024];
            int len = 0;
            while ((len = in.read(buf))!=-1)
            {
                fos.write(buf,0,len);
            }
            OutputStream out = s.getOutputStream();

            out.write("上传成功".getBytes());

            fos.close();

            s.close();
        }
        catch (Exception e)
        {
            throw new RuntimeException(ip+"上传失败");
        }
    }
}
class PicServer0
{
    public static void main(String[] args) throws Exception
    {
        ServerSocket ss = new ServerSocket(10008);

        while (true)
        {
            Socket s = ss.accept();

            new Thread(new PicThread(s)).start();


        }
    }
}
public class TcpDemo4 {
}

22.gif