在service()方法中连接数据库获取表信息
package com.shige.controller;
import javax.servlet.*;
import java.io.IOException;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.sql.*;
public class ListEmpServlet implements Servlet {
@Override
public void init(ServletConfig servletConfig) throws ServletException {
}
@Override
public ServletConfig getServletConfig() {
return null;
}
@Override
public void service(ServletRequest request, ServletResponse response) throws ServletException, IOException {
//防止乱码
//response.setCharacterEncoding("text/html;charset=UTF-8");
response.setContentType("text/html;charset=utf-8");
//创建字符输出流
PrintWriter printWriter=response.getWriter();
//HTML代码
printWriter.print(" <!DOCTYPE html>");
printWriter.print("<meta http-equiv=\"content-type\" content=\"text/html\" charset=\"utf-8\"/> ");
printWriter.print(" <head>");
printWriter.print(" <meta charset='UTF-8'>");
printWriter.print(" <title>员工信息</title>");
printWriter.print(" </head>");
printWriter.print(" <body>");
printWriter.print(" <h3 align='center'>员工信息表</h3>");
printWriter.print(" <hr width='60%'>");
printWriter.print(" <table border='1' align='center' width='50%'>");
printWriter.print(" <tr align='center'>");
printWriter.print(" <th>序号</th>");
printWriter.print(" <th>员工编号</th>");
printWriter.print(" <th>员工姓名</th>");
printWriter.print(" <th>员工薪酬</th>");
printWriter.print(" <th>员工岗位</th>");
printWriter.print(" </tr>");
//JDBC连接数据库
//创建连接对象
Connection connection=null;
PreparedStatement preparedStatement=null;
ResultSet resultSet=null;
try {
//注册驱动
Class.forName("com.mysql.cj.jdbc.Driver");
//获取连接
connection=DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/employ?useUnicode=true&characterEncoding=utf8&serverTimezone=Asia/Shanghai",
"root","123456");
//获取预编译对象
String sql="select empno,ename,sal,job from emp";
preparedStatement=connection.prepareStatement(sql);
//执行SQL语句
resultSet=preparedStatement.executeQuery();
//处理查询结果集
int i=1;
while(resultSet.next()){
String empno=resultSet.getString("empno");
String name=resultSet.getString("ename");
String sal=resultSet.getString("sal");
String job=resultSet.getString("job");
printWriter.print(" <tr align='center'>");
printWriter.print(" <th>"+(i++)+"</th>");
printWriter.print(" <th>"+empno+"</th>");
printWriter.print(" <th>"+name+"</th>");
printWriter.print(" <th>"+sal+"</th>");
printWriter.print(" <th>"+job+"</th>");
printWriter.print(" </tr>");
}
} catch (ClassNotFoundException | SQLException e) {
e.printStackTrace();
}finally {
if(resultSet!=null){
try {
resultSet.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if(preparedStatement!=null){
try {
preparedStatement.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if(connection!=null){
try {
connection.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
printWriter.print(" </table>");
printWriter.print(" </body>");
printWriter.print(" </html>");
}
@Override
public String getServletInfo() {
return null;
}
@Override
public void destroy() {
}
}