下面的结构图

1.在src你创建com.hqyj.wj.model建立model包,model里放数据库的元素,User.java的截图

package com.hqyj.wj.model;

//用户信息表

public class User {

private int id;

private String name;

private String birthday;

public int getId() {

return id;

}

public void setId(int id) {

this.id = id;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getBirthday() {

return birthday;

}

public void setBirthday(String birthday) {

this.birthday = birthday;

}

}

2.在src你创建com.hqyj.wj.dao.inf建立包,这个包是放接口类,这是UserDaoInf的截图

package com.hqyj.wj.dao.inf;

import java.util.List;

import com.hqyj.wj.model.User;

/**

* 数据访问层的接口定义数据接口的方法

*

*/

public interface UserDaoInf {

//定义一个查询方法

List search();

}

3.在src你创建com.hqyj.wj.dao建立包,这个包连接数据库,及实现上面的接口类

package com.hqyj.wj.dao;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.util.ArrayList;

import java.util.List;

import com.hqyj.wj.dao.inf.UserDaoInf;

import com.hqyj.wj.model.User;

/**

*

* @author wl 数据访问接口

*/

public class UserDao implements UserDaoInf {

// 数据访问数据库的连接对象

protected Connection con = null;

//预编译你写的sql语句

protected PreparedStatement ps=null;

//查询预编译的sql语句

protected ResultSet rs=null;

// 获取数据库链接

@SuppressWarnings("finally")

public Connection getCon() {

try {

// 加载mysql驱动

Class.forName("com.mysql.jdbc.Driver");

//获取数据库链接

con=DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/image?characterEncoding=utf8", "root", "root");

System.out.println("链接成功");

return con;

} catch (Exception e) {

System.out.println("链接失败"+e.getMessage());

return null;

//} finally {

//try {

//con.close();

//} catch (SQLException e) {

TODO Auto-generated catch block

//e.printStackTrace();

//return null;

//}

//

}

}

/**

* 查询方法

*/

public List search() {

List list=new ArrayList();

try {

//定义一个sql语句

//String sql="SELECT a.id as 序号,a.salary as '薪水',b.`name` as '姓名' from salary a LEFT JOIN `user` b on a.u_id=b.id";

String sql="SELECT * from user";

//获取数据库连接

con=getCon();

//预编译sql语句

ps=con.prepareStatement(sql);

//把编译出来的结果集装载到ResultSet对象里面

rs=ps.executeQuery();

// rs=statement.executeQuery(sql);

//取出ResultSet里的结果集装载到数据模型里

while(rs.next()){

User user=new User();

user.setName(rs.getString("name"));

user.setBirthday(rs.getString("birthday"));

user.setId(Integer.parseInt(rs.getString("id")));

list.add(user);

}

} catch (Exception e) {

System.out.println("查询错误"+e.getMessage());

}finally{

try {

rs.close();

ps.close();

con.close();

} catch (Exception e2) {

e2.printStackTrace();

}

}

return list;

}

}

5.要引入数据库包mysql-connector-java-commercial-5.1.25-bin.jar,和json-lib-2.2.3-jdk15.jar在项目名字上右键->properties->java Build Path->Libraries->Add External Jars然后选择你下载的包

6.在src下面创建测试类

import java.util.List;

import com.hqyj.wj.dao.UserDao;

import com.hqyj.wj.model.User;

public class Test {

/**

* @param args

*/

public static void main(String[] args) {

//获取数据库访问类对象

UserDao dao=new UserDao();

dao.getCon();

List list=dao.search();

for(int i=0;i

System.out.println("id=="+list.get(i).getId());

System.out.println("name=="+list.get(i).getName());

System.out.println("birthday=="+list.get(i).getBirthday());

}

}

}

7.成功显示

8.src创建服务类和接口,UserServiceInf和UserService

package com.hqyj.wj.service.inf;

import java.util.List;

import com.hqyj.wj.model.User;

public interface UserServiceInf {

List search();

}

package com.hqyj.wj.service;

import java.util.List;

import com.hqyj.wj.dao.UserDao;

import com.hqyj.wj.dao.inf.UserDaoInf;

import com.hqyj.wj.model.User;

import com.hqyj.wj.service.inf.UserServiceInf;

/**

*逻辑服务层实现类

*/

public class UserService implements UserServiceInf{

UserDaoInf us=new UserDao();

public List search() {

return us.search();

}

}

9.src创建控制层　,下新建个服务

package com.hqyj.wj.controller;

import java.io.IOException;

import java.io.PrintWriter;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import net.sf.json.JSONArray;

import com.hqyj.wj.service.*;

import com.hqyj.wj.service.inf.*;

import com.hqyj.wj.model.*;

import java.util.List;

import java.util.ArrayList;

public class OneServlet extends HttpServlet {

public OneServlet() {

super();

}

public void destroy() {

super.destroy(); // Just puts "destroy" string in log

// Put your code here

}

//doget对应的是ajax的$.get()方法

//request是装载请求数据

//response响应数据到前端对象

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

//解决中文乱码的问题

request.setCharacterEncoding("utf-8");

response.setCharacterEncoding("utf-8");

//在服务器端设置允许在其他域名下访问，及响应类型、响应头设置

System.out.println("这是");

response.setHeader("Access-Control-Allow-Origin", "*");

response.setHeader("Access-Control-Allow-Methods","POST");

response.setHeader("Access-Control-Allow-Headers","x-requested-with,content-type");

//响应的文本格式

response.setContentType("text/html");

//获取响应的输出对象

PrintWriter out = response.getWriter();

//out.print("nissssss");

//out.print("您好呀");

//创建服务器层实现类

UserServiceInf service=new UserService();

List list=service.search();

//把list数据解析成前端页面能读取的数据

JSONArray json=JSONArray.fromObject(list);

out.print(json.toString());

out.flush();

out.close();

}

//doget对应的是ajax的$.post()方法

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("text/html");

PrintWriter out = response.getWriter();

out.println(""-//W3C//DTD HTML 4.01 Transitional//EN\">");

out.println("");

out.println("

A Servlet");

out.println("

");

out.print(" This is ");

out.print(this.getClass());

out.println(", using the POST method");

out.println(" ");

out.println("");

out.flush();

out.close();

}

public void init() throws ServletException {

// Put your code here

}

}

10.新建一个html,获取数据库数据

ajax获取集合

id姓名生日

$.get("http://localhost:8080/jquery/servlet/OneServlet",function(data){varnum=eval(data);varstr;//for(var o in num){//console.log(num[o].name);//str+="

"+num[o].id+" "+num[o].name+" "+num[o].birthday+"";//$("tbody").html(str)//}

for(vari=0;i

str+="

"+num[i].id+" "+num[i].name+" "+num[i].birthday+"";

}

$("tbody").html(str)

})

})