Question

当我尝试连接到db时，我收到500错误并关闭我的eclipse / tomcat。有谁知道我怎么能解决它？

确认Servlet

package be.pxl.tafelboeker.servlets;

import be.pxl.tafelboeker.dao.BoekingDAO;
import be.pxl.tafelboeker.domain.Boeking;
import be.pxl.tafelboeker.services.BoekingService;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebInitParam;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import java.io.IOException;

@WebServlet(value = "/Confirm", initParams = {
          @WebInitParam(name = "ConfirmPage",
                value = "/confirm.jsp") })
public class ConfirmServlet extends HttpServlet {
    private String ConfirmPage;
    private String geluktPage;
    private String misluktPage;
    private BoekingService service = new BoekingService();



    @Override
    public void init() throws ServletException {
        // TODO Auto-generated method stub
        super.init();
        ConfirmPage = getInitParameter("ConfirmPage");
        geluktPage ="gelukt.jsp";
        misluktPage = "mislukt.jsp";
    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        Boeking bean = new Boeking();
        HttpSession sess = request.getSession();
        bean = (Boeking)sess.getAttribute("bean");
        request.setAttribute("bean", bean);
        request.getRequestDispatcher(ConfirmPage).forward(request,response);

    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO STUDENT : boek tafel, toon gelukt.jsp indien de boeking gelukt is en toon mislukt.jsp indien de tafel niet geboekt kan worden
        Boeking bean = new Boeking();
        HttpSession sess = request.getSession();
        bean = (Boeking)sess.getAttribute("bean");
        BoekingDAO dao = new BoekingDAO("jdbc:mysql://localhost/survey", "root", "");
        BoekingService serv = new BoekingService();
        serv.setDao(dao);



        if (serv.boekTafel(bean)) {
            request.getRequestDispatcher(geluktPage).include(request,response);
        } else {
            request.getRequestDispatcher(misluktPage).include(request,response);
        }

        //Krijg een error bij het aanroepen van mijn Persistence krijg deze pas vandaag als ik mijn oefeningen van gister wil openen die werkte krijg ik het nu ook
                //Dit is zeer vervelend. Kan nu niet testen of mijn query en de rest wel klopt.
                //Heb mijn best gedaan om het zo goed mogelijk in te zullen
                //Hetzelfde geld voor overzichtservlet & overzicht.jsp die ook dezelfde fout krijgen

    }
}

Boeking Dao

package be.pxl.tafelboeker.dao;

import be.pxl.tafelboeker.domain.Boeking;

import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityManager;
import javax.persistence.Persistence;
import javax.persistence.Query;

import java.time.LocalDate;
import java.util.Calendar;
import java.util.Date;
import java.util.List;

public class BoekingDAO {

    private String url;
    private String user;
    private String password;

    EntityManagerFactory emf;

    public BoekingDAO(String url, String user, String password) {
        this.url = url;
        this.user = user;
        this.password = password;
    }

    public void setDriver(String driver)
             throws ClassNotFoundException {
           Class.forName("com.mysql.jdbc.Driver");
       }

    private EntityManager getEntityManager() {
        emf = Persistence.createEntityManagerFactory("booking");
        EntityManager em = emf.createEntityManager();
        return em;

    }

    // TIP : Gebruik TemporalType.DATE voor je query parameter
    public boolean isTafelBeschikbaar(LocalDate dag, int uur) {
        EntityManager em = getEntityManager();
        Query q1 = em.createQuery("select b from booking as b where (b.dag=?1 AND b.uur =?2) ");
        q1.setParameter(1, dag);
        q1.setParameter(2, uur);
        if (q1.getMaxResults() == 0) {
            return true;
        } else {
            return false;
        }

    }

    public void boekTafel(Boeking bean) {
        EntityManager em = getEntityManager();
        em.persist(bean);
        em.close();
        emf.close();

    }

    public String getUrl() {
        return url;
    }

    public void setUrl(String url) {
        this.url = url;
    }

    public String getUser() {
        return user;
    }

    public void setUser(String user) {
        this.user = user;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }



}

DriverLoader

package be.pxl.tafelboeker.dao;

public class DriverLoader {
    static{
        System.out.print("loading database");
        try {
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            System.out.println("nope");
            e.printStackTrace();
        }
    }

}

偷看服务

package be.pxl.tafelboeker.services;

import be.pxl.tafelboeker.dao.BoekingDAO;
import be.pxl.tafelboeker.domain.Boeking;

import java.time.LocalDate;
import java.util.Date;

public class BoekingService {

    private BoekingDAO dao;

    public BoekingService(){
    }


    public BoekingDAO getDao() {
        return dao;
    }


    public void setDao(BoekingDAO dao) {
        this.dao = dao;
    }


    private boolean isTafelBeschikbaar(LocalDate dag, int uur){
        return dao.isTafelBeschikbaar(dag, uur)  ;
    }

    public boolean boekTafel(Boeking boeking){
        LocalDate dag = boeking.getDag();
        int uur = boeking.getUur();
        if(isTafelBeschikbaar(dag, uur)){
            dao.boekTafel(boeking);
            return true;
        }
        return false;
    }
}

POM

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>be.pxl</groupId>
  <artifactId>HerexamensOef</artifactId>
  <packaging>war</packaging>
  <version>0.0.1-SNAPSHOT</version>
  <name>HerexamensOef Maven Webapp</name>
  <url>http://maven.apache.org</url>
  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
    <dependency>
            <groupId>javax</groupId>
            <artifactId>javaee-web-api</artifactId>
            <version>7.0</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>jstl</artifactId>
    <version>1.2</version>
</dependency>

  </dependencies>
  <build>
    <finalName>HerexamensOef</finalName>
  </build>
</project>

持久性

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence
http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd"
    version="2.1">
    <persistence-unit name="booking" transaction-type="RESOURCE_LOCAL">
        <properties>
            <property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
            <property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost/booking" />
            <property name="javax.persistence.jdbc.user" value="root" />
            <property name="javax.persistence.jdbc.password" value="" />
            <property name="javax.persistence.schema-generation.database.action"
                value="none" />
            <!-- Hibernate specific -->
            <property name="hibernate.show_sql" value="true" />
        </properties>
    </persistence-unit>
</persistence>

错误

HTTP Status 500 - Servlet execution threw an exception

type Exception report

message Servlet execution threw an exception

description The server encountered an internal error that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: Servlet execution threw an exception
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

root cause

java.lang.NoClassDefFoundError: javax/persistence/Persistence
    be.pxl.tafelboeker.dao.BoekingDAO.getEntityManager(BoekingDAO.java:35)
    be.pxl.tafelboeker.dao.BoekingDAO.isTafelBeschikbaar(BoekingDAO.java:43)
    be.pxl.tafelboeker.services.BoekingService.isTafelBeschikbaar(BoekingService.java:28)
    be.pxl.tafelboeker.services.BoekingService.boekTafel(BoekingService.java:34)
    be.pxl.tafelboeker.servlets.ConfirmServlet.doPost(ConfirmServlet.java:59)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

note The full stack trace of the root cause is available in the Apache Tomcat/8.0.33 logs.

预订SQL

-- phpMyAdmin SQL Dump
-- version 4.4.10
-- http://www.phpmyadmin.net
--
-

    - Host: localhost
    -- Generation Time: Jun 03, 2016 at 06:50 PM
    -- Server version: 5.5.42
    -- PHP Version: 7.0.0

    SET SQL_MODE = "NO_AUTO_VALUE_ON_ZERO";
    SET time_zone = "+00:00";

    --
    -- Database: `boekingdb`
    --

    -- --------------------------------------------------------

    --
    -- Table structure for table `BOOKING`
    --

    CREATE TABLE `BOOKING` (
      `id` bigint(20) NOT NULL,
      `DAY` date DEFAULT NULL,
      `NAME` varchar(255) DEFAULT NULL,
      `CITY` varchar(255) DEFAULT NULL,
      `STREET` varchar(255) DEFAULT NULL,
      `HOUR` int(11) DEFAULT NULL
    ) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=latin1;


    --
    -- Indexes for table `BOOKING`
    --
    ALTER TABLE `BOOKING`
      ADD PRIMARY KEY (`id`);

    --
    -- AUTO_INCREMENT for dumped tables
    --

    --
    -- AUTO_INCREMENT for table `BOOKING`
    --
    ALTER TABLE `BOOKING`
      MODIFY `id` bigint(20) NOT NULL AUTO_INCREMENT,AUTO_INCREMENT=4;

Answer 1

您的持久性文件使用2.1版本的JPA架构：

{"seatCode":"40B"}

所以你应该使用匹配的hibernate版本：min Hibernate 4.3.X. 我想你在persistence.xml中使用Hibernate

<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence
             http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd"
             version="2.1">

因此，如果您想使用JPA作为接口，则应在pom.xml中添加此依赖项：

<property name="hibernate.show_sql" value="true" />

此依赖项包括<dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-entitymanager</artifactId> <version>5.2.2.Final</version> </dependency>，其中包含类hibernate-jpa-2.1-api

否则，如果你想直接使用Hibernate而不使用JPA作为接口，你可以使用这个依赖（或+ 4.3.X）：

javax.persistence.Persistence

此处有更多详情：http://hibernate.org/orm/downloads/

Answer 2

您必须将javax.persistence-api.jar添加为依赖项：

<!-- https://mvnrepository.com/artifact/javax.persistence/persistence-api -->
<dependency>
    <groupId>javax.persistence</groupId>
    <artifactId>persistence-api</artifactId>
    <version>1.0.2</version>
</dependency>

Tomcat无法连接到db Error Status 500 java.lang.ClassNotFoundException

2 个答案: