[英]How to send JSONobject over TCP?
我试图了解如何发送我的自定义对象“纸”,它通过 TCP 使用 JSON 序列化。
客户端:
import org.json.JSONObject;
import java.io.*;
import java.net.ConnectException;
import java.net.NoRouteToHostException;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.Scanner;
import model.*;
import view.*;
/**
*/
public class JSONClient {
private String host;
private int port;
private Socket socket;
private final String DEFAULT_HOST = "localhost";
public void connect(String host, int port) throws IOException {
this.host = host;
this.port = port;
socket = new Socket(host, port);
System.out.println("Client has been connected..");
}
/**
* use the JSON Protocol to receive a json object as
* from the client and reconstructs that object
*
* @return JSONObejct with the same state (data) as
* the JSONObject the client sent as a String msg.
* @throws IOException
*/
public JSONObject receiveJSON() throws IOException {
InputStream in = socket.getInputStream();
ObjectInputStream i = new ObjectInputStream(in);
JSONObject line = null;
try {
line = (JSONObject) i.readObject();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return line;
}
public void sendJSON(JSONObject jsonObject) throws IOException {
JSONObject jsonObject2 = new JSONObject();
jsonObject2.put("key", new Paper(250,333));
OutputStream out = socket.getOutputStream();
ObjectOutputStream o = new ObjectOutputStream(out);
o.writeObject(jsonObject2);
out.flush();
System.out.println("Sent to server: " + " " + jsonObject2.get("key").toString());
}
public static void main(String[] args) {
JSONClient client = new JSONClient();
try{
client.connect("localhost", 7777);
// For JSON call sendJSON(JSON json) & receiveJSON();
JSONObject jsonObject2 = new JSONObject();
jsonObject2.put("key", new Paper(250,333));
client.sendJSON(jsonObject2);
client.receiveJSON();
}
catch (ConnectException e) {
System.err.println(client.host + " connect refused");
return;
}
catch(UnknownHostException e){
System.err.println(client.host + " Unknown host");
client.host = client.DEFAULT_HOST;
return;
}
catch (NoRouteToHostException e) {
System.err.println(client.host + " Unreachable");
return;
}
catch (IllegalArgumentException e){
System.err.println(client.host + " wrong port");
return;
}
catch(IOException e){
System.err.println(client.host + ' ' + e.getMessage());
System.err.println(e);
}
finally {
try {
client.socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
服务器 :
import model.*;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.ServerSocket;
import java.net.Socket;
/**
*/
public class JSONServer {
private ServerSocket serverSocket;
private int port;
public static int clients = 0;
public void establish(int port) throws IOException {
this.port = port;
serverSocket = new ServerSocket(port);
System.out.println("JSONServer has been established on port " + port);
}
public void accept() throws IOException {
while (true) {
Socket socket = serverSocket.accept();
Runnable r = new MyThreadHandler(socket);
Thread t = new Thread(r);
t.start();
}
}
private static class MyThreadHandler implements Runnable {
private Socket socket;
MyThreadHandler(Socket socket) {
this.socket = socket;
}
@Override
public void run() {
clients++;
System.out.println(clients + " JSONClient(s) connected on port: " + socket.getPort());
try {
// For JSON Protocol
JSONObject jsonObject = receiveJSON();
sendJSON(jsonObject);
} catch (IOException e) {
} finally {
try {
closeSocket();
} catch (IOException e) {
e.printStackTrace();
}
}
}
public void closeSocket() throws IOException {
socket.close();
}
/**
* use the JSON Protocol to receive a json object as
* String from the client and reconstructs that object
* @return JSONObejct with the same state (data) as
* the JSONObject the client sent as a String msg.
* @throws IOException
*/
public JSONObject receiveJSON() throws IOException {
InputStream in = socket.getInputStream();
ObjectInputStream i = new ObjectInputStream(in);
JSONObject line = null;
try {
line = (JSONObject) i.readObject();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
JSONObject jsonObject = new JSONObject(line);
System.out.println("Got from client on port " + socket.getPort() + " " + jsonObject.get("key").toString());
return jsonObject;
}
public void sendJSON(JSONObject jsonObject) throws IOException {
JSONObject jsonObject2 = new JSONObject();
jsonObject2.put("key", new Paper(250,369));
OutputStream out = socket.getOutputStream();
ObjectOutputStream o = new ObjectOutputStream(out);
o.writeObject(jsonObject2);
out.flush();
System.out.println("Sent to server: " + " " + jsonObject2.get("key").toString());
}
}
public void start(int port) throws IOException{
establish(port);
accept();
}
public static void main(String[] args) {
JSONServer server = new JSONServer();
try {
server.start(7777);
} catch (IOException e) {
System.err.println(e.getMessage());
System.err.println(e);
}
}
}
虽然类论文是序列化我得到错误:
本地主机 org.json.JSONObject
java.io.NotSerializableException: org.json.JSONObject
您正在使用ObjectOutputStream
来序列化您的数据。 该序列化使用它自己的实现,将Serializable
对象转换为字节表示,然后通过您的套接字发送。
JSON 用于将对象序列化为String
表示形式。 不幸的是,您从不使用 json 序列化,而是尝试通过您的套接字发送您的 JSON 对象。
我的建议:使用将您的对象转换为字符串
String strJson = jsonObject.toString();
然后使用您的ObjectOutputStream
发送一个字符串。 在接收端将其读取为字符串,然后通过将该字符串传递给构造函数将其转换回 JSONObject:
JSONObject js = new JSONObject(strJson);
只需将行更改为
o.writeObject(jsonObject2.toString());
使用 .toString() 方法获取 JSONObject 的字符串。
这个对我有用 :)
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