Servlet搭建Javaweb项目

 一、项目目录结构

 二、代码展示　

package com.zlj.bean;

public class Message {

    private int id;
    private String name;
    private String email;
    private  String message;


    //构造方法

    public Message() { //无参构造
        super();
    }

    public Message(int id, String name, String email, String message) {
        this.id = id;
        this.name = name;
        this.email = email;
        this.message = message;
    }
    //set get 方法
    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 getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }

    @Override
    public String toString() {
        return "Message{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", email='" + email + '\'' +
                ", message='" + message + '\'' +
                '}';
    }
}

package com.zlj.dao;

import com.zlj.bean.Message;

import java.util.List;

public interface MessageDao {
    List<Message> messageDao();
}

package com.zlj.dao;

import com.sun.xml.internal.bind.v2.model.core.ID;
import com.zlj.bean.Message;
import com.zlj.connection.LinkDb;
import com.zlj.connection.connection;

import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.LinkedList;
import java.util.List;

public class MessageDaoImpl implements MessageDao {

    @Override
    public List<Message> messageDao() {

        LinkDb linkDb = new LinkDb();
        linkDb.LinkDB();
        String sql = "select * from message";
        List<Message> resultList = new LinkedList<>();
        try {
            PreparedStatement pst = linkDb.conn.prepareStatement(sql);
            ResultSet resultSet = pst.executeQuery();
            while (resultSet.next() == true){
                Message message = new Message();
                message.setEmail(resultSet.getString("name"));
                message.setId(resultSet.getInt("id"));
                message.setName(resultSet.getString("name"));
                message.setMessage(resultSet.getString("message"));
                resultList.add(message);
            }
        }catch (SQLException e){
            e.getMessage();
        }

        return resultList;
    }
}

package com.zlj.service;

import com.zlj.bean.Message;

import java.util.List;

public interface MessageService {

    List<Message> searchMessage();//查询message
}

package com.zlj.service;

import com.zlj.bean.Message;
import com.zlj.dao.MessageDao;
import com.zlj.dao.MessageDaoImpl;

import java.util.List;

public class MessageServiceImpl implements MessageService {
    @Override
    public List<Message> searchMessage() {

        MessageDao messageDao = new MessageDaoImpl();
        return messageDao.messageDao();
    }
}

package com.zlj.servlet;

import com.zlj.bean.Message;
import com.zlj.service.MessageService;
import com.zlj.service.MessageServiceImpl;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;

import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.text.SimpleDateFormat;
import java.util.List;

public class MessageServlet extends HttpServlet {
    @Override
    public void service(ServletRequest req, ServletResponse res) throws ServletException, IOException {

        res.setContentType("application/json;charset=utf-8");
        res.setCharacterEncoding("UTF-8");
       try {
           MessageService messageService = new MessageServiceImpl();
           List<Message> resultList = messageService.searchMessage();
           for (Message message : resultList) {
               System.out.println(message);
           }
           JSONObject resultObject = new JSONObject();
           JSONArray resultArray = new JSONArray();
           SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");//注意月份是MM
           simpleDateFormat.setLenient(false);
           for (Message message : resultList) {
               resultObject.put("name", message.getName());
               resultObject.put("message", message.getMessage());
               resultObject.put("id", message.getId());
               resultObject.put("email", message.getEmail());
               resultArray.add(resultObject);
           }
           JSONObject object = new JSONObject();
           object.put("code", 200);
           object.put("starus", true);
           object.put("msg", "获取成功");
           object.put("list", resultArray);
           PrintWriter out = res.getWriter();
           out.print(object);
           out.flush();
           out.close();
       }
       catch (IOException e){
           e.getMessage();
       }
        System.out.println("接口请求--zlj\n\n");
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doGet(req,resp);
    }
}

package com.zlj.connection;

public interface connection {

   public void LinkDB();//连接数据库
}

package com.zlj.connection;

import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Connection;


public class LinkDb implements connection {


    public Connection conn;
    private  String DB_URL="jdbc:mysql://localhost:3306/sale?useUnicode=true&characterEncoding=UTF-8";
    private String USER="root";
    private String PASS="aaaa123456";

    @Override
    public void LinkDB() { //实现连接书库的方法
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            conn = DriverManager.getConnection(DB_URL,USER,PASS);
        }catch (ClassNotFoundException e){
            e.printStackTrace();
        } catch (SQLException throwables){
            throwables.printStackTrace();
        }
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    
    
    <servlet>
        <servlet-name>ServletTest</servlet-name>
        <servlet-class>com.zlj.test.ServletTest</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>ServletTest</servlet-name>
        <url-pattern>/servlettest</url-pattern>
    </servlet-mapping>



    <servlet>
        <servlet-name>MessageServlet</servlet-name>
        <servlet-class>com.zlj.servlet.MessageServlet</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>MessageServlet</servlet-name>
        <url-pattern>/message</url-pattern>
    </servlet-mapping>
</web-app>

  三、浏览器请求

四、项目用到的jar包 

[常用jar包介绍](https://www.dandelioncloud.cn/article/details/1534515353262780417)
[1.commons-beanutils-1.8.3.jar的介绍](https://www.yiibai.com/commons_collections/commons_collections_overview.html)
[2.commons-collections-3.2.1.jar的介绍](https://www.yiibai.com/commons_collections/commons_collections_overview.html)
[3.commons-lang-2.6.jar](https://www.cnblogs.com/stepforeward/p/16873154.html)
[4.commons-logging-1.1.1.jar](https://www.cnblogs.com/wuyongyin/p/12421153.html)
[5.ezmorph-1.0.6.jar](https://www.cnblogs.com/timssd/p/5753654.html)
[6.javax.servlet.jar和javax.servlet-api的区别](https://zhidao.baidu.com/question/180732714630314164.html)

 五、数据库数据