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JAVA 全系列/第二十一阶段:分布式医疗云平台/基础功能搭建 36706楼
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<p>老师这是HelloWorld.vue</p>

<template>
  <div class="hello">
    <h3>Hello World</h3>
    <ul>
      <li v-for="(item, index) in banner" :key="index">
        <p>{{ item.title }}</p>
      </li>
    </ul>
  </div>
</template>

<script>
import api from "../api";

export default {
  name: "HelloWorld",
  data() {
    return {
      banner: [],
    };
  },
  created() {},
  mounted() {
    // axios.get("http://iwenwiki.com/api/blueberrypai/getIndexBanner.php").then(res =>{
    //   this.banner = res.data.banner
    // })

    // /**
    //  * user_id=iwen@qq.com&password=iwen123
    //  */
    // axios.post("http://iwenwiki.com/api/blueberrypai/login.php",qs.stringify({
    //   user_id:"iwen@qq.com",
    //   password:"iwen123",
    //   verification_code:"crfvw"
    // })).then(res =>{
    //   console.log(res.data);
    // })
    api.getBanner().then((res) => {
      this.banner = res.data.banner;
    });

    api.getLogin({
      user_id: "iwen@qq.com",
      password: "iwen123",
      verification_code: "crfvw",
    }).then(res =>{
      console.log(res.data);
    }).catch(error =>{
      console.log(error);
    })
  },
  updated() {},
  destoryed() {},
};
</script>
/*request.js文件*/
import axios from "axios"
import qs from "querystring"


/*
*错误信息处理函数
*/
const errorsHandle = (status,info) =>{

    switch(status){
        case 400:
            console.log("语义有误,当前请求无法被服务器理解。除非进行修改,否则客户端不应该重复提交这个请求。")
            break;
        case 401:
            // token:令牌
            console.log("服务器认证失败")
            break;
        case 403:
            console.log("服务器已经理解请求,但是拒绝执行它");
            break;
        case 404:
            console.log("请检查网络请求地址")
            break;
        case 500:
            console.log("服务器遇到了一个未曾预料的状况,导致了它无法完成对请求的处理。一般来说,这个问题都会在服务器的程序码出错时出现。")
            break;
        case 502:
            console.log("作为网关或者代理工作的服务器尝试执行请求时,从上游服务器接收到无效的响应。")
            break;
        default:
            console.log(info)
            break;


    }

}


/*
*创建Axios的实例对象
*/
var instance = axios.create({
  timeout: 5000,

});

/*
*拦截器
*/

instance.interceptors.request.use(

    config =>{

        if(config.method === "post"){

            config.date = qs.stringify(config.data)

        }
        return config;

   },
   error =>{

    return Promise.reject(error);

   }


)


/*
*响应拦截
*/
instance.interceptors.request.use(

    response => response.status === 200 ? Promise.resolve(response) : Promise.reject(response) ,

    error =>{

        const { response } = error;
        if(response){

            errorsHandle(response.status,response.info);

        }else{

            console.log("请求被中断了");

        }

    }

)

export default instance;
/*base.js文件*/
/*
*存储网路请求路径
*/

const base = {
    baseUrl:"http://iwenwiki.com",                  // 公共地址
    banner:"/api/blueberrypai/getIndexBanner.php",  // 主页banner数据
    login:"/api/blueberrypai/login.php"            // 登陆地址
}

export default base;
/*index.js文件*/
/*
*提供网路请求方法
*/

import axios from "../utils/request"
import base from "./base"

const api = {

    getBanner(){

        return axios.get(base.baseUrl + base.banner)

    },

    getLogin(params){  //params是一个对象类型

        return axios.post(base.baseUrl + base.login,params)
    }

}

export default api;

vue-axios - 联想浏览器 2021_7_18 11_58_18.png

老师,帮我看一下是网络路径错了吗?

Python 全系列/第八阶段:Vue框架/vue框架 36708楼
JAVA 全系列/第十一阶段:消息中间件与高并发处理/RabbitMQ 36709楼

package com.example.dao.DaoImpl;

import com.example.dao.DaoInterface.Dao_UserLoginInterface;
import com.example.pojo.Users;
import com.example.utils.JdbcUtils;

import java.sql.*;

public class Dao_UserLoginImplClass implements Dao_UserLoginInterface {

    /**
     * 用户登录数据库查询
     * @param username
     * @param userpwd
     * @return
     */

    @Override
    public Users SelectUserByUserNameAndUserPwd(String username, String userpwd) {

        Users user = null;
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        try{
            System.out.println(1);//用于定位
            conn = JdbcUtils.JDBC_Connection();
            System.out.println(2);//用于定位
            ps = conn.prepareStatement("select * from oneselfproject.user where user.UserID = ? and user.UserName = ?");
            System.out.println(3);//用于定位
            ps.setString(1,username);
            ps.setString(2,userpwd);
            System.out.println(4);//用于定位
            rs= ps.executeQuery();
            System.out.println(5);//用于定位
            while (rs.next()){
                user = new Users();
                user.setUserID(rs.getString("UserID"));
                user.setUserName(rs.getString("UserName"));
                user.setUserEmial(rs.getString("UserEmial"));
            }
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            JdbcUtils.JDBC_Release_Resources(conn,ps,rs);
        }
        return user;
    }
}

老师,dao层的代码,我现在连接数据库有问题。我对他进行定位,发现现在在这里出现了问题,导致返回的对象都是null;

ps = conn.prepareStatement("select * from oneselfproject.user where user.UserID = ? and user.UserName = ?");



报错的结果:

[2021-08-03 11:54:10,892] Artifact OneSelfProject_Test:war exploded: Artifact is deployed successfully
[2021-08-03 11:54:10,892] Artifact OneSelfProject_Test:war exploded: Deploy took 23,134 milliseconds
1
2
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1364)
	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1187)
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:264)
	at com.example.utils.JdbcUtils.<clinit>(JdbcUtils.java:29)
	at com.example.dao.DaoImpl.Dao_UserLoginImplClass.SelectUserByUserNameAndUserPwd(Dao_UserLoginImplClass.java:27)
	at com.example.service.ServiceImpl.Service_UserLoginImplClass.ServiceUserLoginClass(Service_UserLoginImplClass.java:13)
	at com.example.servlet.Login.UserLoginServlet.doPost(UserLoginServlet.java:37)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:652)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:733)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:687)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:346)
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:887)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1684)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Thread.java:748)
java.sql.SQLException: No suitable driver found for jdbc:mysql://localhost:3306/oneselfproject?useUnicode=true&characterEncoding=utf8
	at java.sql.DriverManager.getConnection(DriverManager.java:689)
	at java.sql.DriverManager.getConnection(DriverManager.java:247)
	at com.example.utils.JdbcUtils.JDBC_Connection(JdbcUtils.java:42)
	at com.example.dao.DaoImpl.Dao_UserLoginImplClass.SelectUserByUserNameAndUserPwd(Dao_UserLoginImplClass.java:27)
	at com.example.service.ServiceImpl.Service_UserLoginImplClass.ServiceUserLoginClass(Service_UserLoginImplClass.java:13)
	at com.example.servlet.Login.UserLoginServlet.doPost(UserLoginServlet.java:37)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:652)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:733)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:687)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:346)
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:887)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1684)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Thread.java:748)
java.lang.NullPointerException
	at com.example.dao.DaoImpl.Dao_UserLoginImplClass.SelectUserByUserNameAndUserPwd(Dao_UserLoginImplClass.java:29)
	at com.example.service.ServiceImpl.Service_UserLoginImplClass.ServiceUserLoginClass(Service_UserLoginImplClass.java:13)
	at com.example.servlet.Login.UserLoginServlet.doPost(UserLoginServlet.java:37)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:652)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:733)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:687)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:346)
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:887)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1684)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Thread.java:748)

为什么在这里会出现这种问题???

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