自己用Java写了个客户端通过服务器实时读取MySQL数据库的程序。JDBC实时读取数据库数据，并每隔1秒发送给客户端，客户端处于一直接收状态，测试用IP：127.0.0.1，端口号为7000。先运行服务器，再运行客户端。源程序如下：
服务端：
package server;
import java.io.*;
import java.net.*;
import java.sql.*;
public class Server{
public static void main(String args[]){
while(true) {
//socket
ServerSocket server=null;
Socket you=null;
try { server =new ServerSocket(7000);
}
catch (IOException el) {
System.out.println("正在监听");
}
try {
System.out.println("等待客户呼叫");
you=server.accept();
System.out.println("客户的地址："+you.getInetAddress());
}
catch(IOException e) {
System.out.println("正在等待客户");
}
if(you!=null) {
ServerThread threadForClient=new ServerThread(you);
threadForClient.start();
}
}
}
}
class ServerThread extends Thread{
static int id;
static int name;
static int password;
static int email;
static int birthday;
Socket socket;
DataOutputStream out=null;
DataInputStream in=null;
String s=null;
ServerThread(Socket t){
socket=t;
try {
out=new DataOutputStream(socket.getOutputStream());
in=new DataInputStream(socket.getInputStream());
} catch (IOException e) {}
}
public void run() {
//JDBC初始化
// JDBC 驱动名及数据库 URL
final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
final String DB_URL = "jdbc:mysql://localhost:3306/data?useSSL=true";
// 数据库的用户名与密码，需要根据自己的设置
final String USER = "root";
final String PASS = "root";
//jdbc
Connection conn = null;
Statement stmt = null;
while(true) {
try {
double r=in.readDouble();
// 注册 JDBC 驱动
Class.forName("com.mysql.jdbc.Driver");
// 打开链接
System.out.println("连接数据库...");
conn = DriverManager.getConnection(DB_URL,USER,PASS);
// 执行查询
System.out.println(" 实例化Statement对象...");
stmt = conn.createStatement();
String sql;
sql = "SELECT id,name,password,email,birthday FROM data";
ResultSet rs = stmt.executeQuery(sql);
if(rs.last()){//只读取最后一个ID
// 通过字段检索
id = rs.getInt("id");
name = rs.getInt("name");
password = rs.getInt("password");
email = rs.getInt("email");
birthday = rs.getInt("birthday");
}
out.writeDouble(ServerThread.id);
out.writeDouble(ServerThread.name);
out.writeDouble(ServerThread.password);
out.writeDouble(ServerThread.email);
out.writeDouble(ServerThread.birthday);
}catch(SQLException se){
// 处理 JDBC 错误
se.printStackTrace();
}catch(Exception e){
// 处理 Class.forName 错误
e.printStackTrace();
}
try{
Thread.sleep(1000);
}
catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
客户端：
package server;
import java.io.*;
import java.net.*;
import java.util.*;
public class Client{
public static void main(String args[]){
Scanner scanner=new Scanner(System.in);
Socket mysocket=null;
DataInputStream in=null;
DataOutputStream out=null;
Thread readData;
Read read=null;
try { mysocket=new Socket();
read=new Read();
readData=new Thread(read);
System.out.print("输入服务器的IP：");
String IP=scanner.nextLine();
System.out.print("输入端口号：");
int port=scanner.nextInt();
InetAddress address = InetAddress.getByName(IP);
InetSocketAddress socketAddress = new InetSocketAddress(address, port);
mysocket.connect(socketAddress);
in = new DataInputStream(mysocket.getInputStream());
out = new DataOutputStream(mysocket.getOutputStream());
read.setDataInputStream(in);
readData.start();
}
catch(Exception e) {
System.out.println("服务器已断开"+e);
}
System.out.println("接收数据:");
while(true) {
double radius=0;
try {
out.writeDouble(radius);
}
catch (Exception e) {}
}
}
}
class Read implements Runnable{
DataInputStream in;
public void setDataInputStream(DataInputStream in) {
this.in=in;
}
public void run() {
double id=0;
double name=0;
double password=0;
double email=0;
double birthday=0;
while (true) {
try {
id=in.readDouble();
System.out.println("id："+id);
name=in.readDouble();
System.out.println("名字："+name);
password=in.readDouble();
System.out.println("密码："+password);
email=in.readDouble();
System.out.println("邮箱："+email);
birthday=in.readDouble();
System.out.println("生日："+birthday);
}
catch (IOException e) {
e.printStackTrace();
}
}
}
}
MySQL数据如下（只有数字），每隔1秒读取最后一行数据：
