How to use JavaWeb to display mysql database data

EMS-Employee Information Management System

Summary of basic operations of MySQL learning

Summary of basic commands of MySQL learning

Create ems library

    show databases;
    create database ems;
    use ems;

Create user table

      create table user(
            id int primary key auto_increment,
            name varchar(50),
            salary double,
            age int
);

Insert table data

   insert into user values(1,'zs',3000,20);
   insert into user values(2,'ls',1000,30);
   insert into user values(3,'ww',5000,25);
   insert into user values(4,'xh',4000,23);

Create UserListServlets

##Use JDBC to connect to the database

Copy the jar package Go to the lib folder

        //使用JDBC连接mysql数据库，将user表中的输出查询处理
        ResultSet result=null;
        Connection con=null;
        try {
            //(1)注册加载驱动
            Class.forName("com.mysql.jdbc.Driver");
            //(2)获得数据库的链接
            //(1).连接mysql的url地址
            String url="jdbc:mysql://localhost:3306/ems";
            //(2).连接mysql的用户名
            String username="root";
            //(3).连接mysql的密码
            String pwd="123456";
            con=DriverManager.getConnection(url, username, pwd);
            //(3)预编译sql语句
            System.out.println("MySQL连接成功！"+con);
            
            //3.预编译SQL语句
            String sql="select * from user";
            PreparedStatement prep=con.prepareStatement(sql);
            //(4)执行sql语句
            result=prep.executeQuery();
            //(5)关闭
            con.close();
            
        } catch (Exception e) {
            e.printStackTrace();
        }

package EMS;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//员工信息查询的Servlet
public class UserListServlets extends HttpServlet {

	
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		//使用JDBC连接mysql数据库，将user表中的输出查询处理
		ResultSet result=null;
		Connection con=null;
		try {
			//(1)注册加载驱动
			Class.forName("com.mysql.jdbc.Driver");
			//(2)获得数据库的链接
			//(1).连接mysql的url地址
			String url="jdbc:mysql://localhost:3306/ems";
			//(2).连接mysql的用户名
			String username="root";
			//(3).连接mysql的密码
			String pwd="123456";
			con=DriverManager.getConnection(url, username, pwd);
			//(3)预编译sql语句
			System.out.println("MySQL连接成功！"+con);
			
			//3.预编译SQL语句
			String sql="select * from user";
			PreparedStatement prep=con.prepareStatement(sql);
			//(4)执行sql语句
			result=prep.executeQuery();
			
			
		} catch (Exception e) {
			e.printStackTrace();
		}
		
		//使用response,获得字符输出流PrintWriter,将查询出的结果输出到浏览器端
		//设置格式编码
		response.setContentType("text/html;charset=utf-8");
		
		//向浏览器端输出一个表格
		PrintWriter pw=response.getWriter();
		pw.println("<table border=&#39;1&#39; cellspacing=&#39;0&#39; width=&#39;400&#39; height=&#39;80&#39; align=&#39;center&#39;>");
		pw.println("<caption>员工信息表</caption>");
		pw.println("<tr align=&#39;center&#39;>");
		pw.println("<td>工号</td><td>姓名</td><td>工资</td><td>年龄</td>");
		pw.println("</tr>");
		try {
			while(result.next())
			{
				pw.println("<tr align=&#39;center&#39;><td>"+result.getInt("id")+"</td><td>"
				+result.getString("name")+"</td><td>"+result.getDouble("salary")+"</td><td>"
				+result.getInt("age")+"</td></tr>");
				System.out.println(result.getInt("id")+"---"+result.getString("name")+"---"+
						result.getDouble("salary")+"---"+result.getInt("age"));
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
		
		
		pw.println("</table>");
		//关闭
		try {
			con.close();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}

}

Deployment server

Re-deployment server reference

Access URL: http://localhost:8080 /Servlet/lists

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