Ajax axios 同时执行两个请求；创建实例化；添加拦截器

    
    
    
    
    
    
    



    axios.all

java time

package ws.wsj.servlet;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
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.Date;



@WebServlet("/time")
public class Time extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    Date d = new Date();
    PrintWriter out = resp.getWriter();
    out.println(sdf.format(d));
    }
}

java user

package ws.wsj.servlet;

import com.alibaba.fastjson.JSONObject;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
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.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;



@WebServlet("/user")
public class UserController extends HttpServlet {
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");
        Connection con = null;
        try{
            Class.forName("com.mysql.cj.jdbc.Driver");
            con = DriverManager.getConnection("jdbc:mysql:/d3?user=root");
        }catch (Exception e){
            e.printStackTrace();
        }
        //接值保存
        if("POST".equals(req.getMethod())){
            String name = req.getParameter("name");
            try{
                PreparedStatement pst = con.prepareStatement("insert into ws value (null,?)");
                pst.setString(1,name);
                pst.executeUpdate();
            }catch (Exception e){
                e.printStackTrace();
            }
        }
        //查数据,并返回
        resp.setCharacterEncoding("utf-8");
        resp.setContentType("text/html;charset=utf-8");
        PrintWriter out = resp.getWriter();
        if("GET".equals(req.getMethod())){
            //从数据库删除数据
            if (req.getParameter("id")!=null){
                try{
                    //转化为数字 Integer.parseInt
                    // 获取参数 getParameter
                    PreparedStatement pst = con.prepareStatement("delete from ws where id = ?");
                    pst.setInt(1,Integer.parseInt(req.getParameter("id")));
                    pst.executeUpdate();
                }catch (Exception e){
                    e.printStackTrace();
                }
            }

            try{
                PreparedStatement pst = con.prepareStatement("select * from ws order by id desc ");
                ResultSet rs = pst.executeQuery();
                //自己写的
                

                //使用fastjson 组件
                List> list = new ArrayList>();
                while (rs.next()){
                    Map map = new HashMap();
                    map.put("id",rs.getInt(1));
                    map.put("name",rs.getString(2));
                    list.add(map);
                }
                out.print(JSONObject.toJSON(list));
            }catch (Exception e){
                e.printStackTrace();
            }
        }
    }
}