如何更正 Spring Boot 应用程序的类路径，使其包含单个兼容版本的 javax.persistence.PersistenceContext？

Question

我正在尝试向我的 Spring Boot 应用程序添加一个参与者存储库接口（它实现了 CrudRepository）。但是这个接口的基本代码在运行时会报错，说必须更正应用程序的类路径。我该怎么做？我可以做其他修改来正确运行代码吗？

//参与者类

package com.example.spring2.participants;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import javax.persistence.Entity;
import javax.persistence.Id;
import java.util.List;

@Entity
public class Participant {

    @Id
    private String name;
    private int age;
    private String job;

    @Autowired
    private ParticipentService participentService;

    public Participant() {
    }

    public Participant(String name, int age, String job) {
        this.name = name;
        this.age = age;
        this.job = job;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getJob() {
        return job;
    }

    public void setJob(String job) {
        this.job = job;
    }

}

//ParticipantController类

package com.example.spring2.participants;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
public class ParticipantController {


    @Autowired
    private ParticipentService participentService;


    @RequestMapping("/people")
    public List<Participant> viewPeople(){
        return participentService.getParticipants();
    }

    @RequestMapping("/people/{name}")
    public Participant getAParticipant(@PathVariable String name) {
        return participentService.getAParticipant(name);
    }

    @RequestMapping(method = RequestMethod.POST, value = "/people")
    public void addParticipant(@RequestBody Participant participant){
        participentService.addParticipant(participant);
    }

    @RequestMapping(method = RequestMethod.PUT, value = "/people/{name}")
    public void updateParticipant(@RequestBody Participant participant, @PathVariable String name) {
        participentService.updateParticipant(participant, name);
    }

    @RequestMapping(method = RequestMethod.DELETE, value = "/people/{name}")
    public void deleteParticipant(@PathVariable String name) {
        participentService.deleteParticipant(name);
    }

}

//ParticipantService类

package com.example.spring2.participants;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.Arrays;
import java.util.List;

@Service
public class ParticipentService {

    private List<Participant> participantList = Arrays.asList(
        new Participant("yasas", 23, "Student"),
        new Participant("anu", 28, "accountant"),
        new Participant("banu", 26, "teacher")
    );

    @Autowired
    private ParticipantRepository participantRepositoty;


    public List<Participant> getParticipants(){

        return participantList;
    }

    public void addParticipant(Participant participant) {
        participantList.add(participant);

    }

    public void updateParticipant(Participant participant, String name ){
        for (int i=0; i < participantList.size(); i++){
            Participant p = participantList.get(i);
            if (p.getName().equals(name)){
                participantList.set(i, participant);
                return;
            }
        }
    }

    public void deleteParticipant(String name ){
        for (int i=0; i < participantList.size(); i++){
            Participant p = participantList.get(i);
            if (p.getName().equals(name)){
                participantList.remove(p);
            }
        }
    }

    public Participant getAParticipant(String name) {
        for (int i=0; i < participantList.size(); i++){
            Participant p = participantList.get(i);
            if (p.getName().equals(name)){
                return p;
            }
        }
        return  null;
    }
}

//POM.xml

<?xml version="1.0" encoding="UTF-8"?>
<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/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
        <groupId>com.example</groupId>
        <artifactId>spring2</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>spring2</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.apache.derby</groupId>
            <artifactId>derby</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>javax.xml.bind</groupId>
            <artifactId>jaxb-api</artifactId>
            <version>2.3.0</version>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

我希望在应用程序运行时启动服务器。但它给出了以下错误。

Description:

An attempt was made to call the method javax.persistence.PersistenceContext.synchronization()Ljavax/persistence/SynchronizationType; but it does not exist. Its class, javax.persistence.PersistenceContext, is available from the following locations:

    jar:file:/C:/Users/Asus/.m2/repository/org/hibernate/javax/persistence/hibernate-jpa-2.0-api/1.0.1.Final/hibernate-jpa-2.0-api-1.0.1.Final.jar!/javax/persistence/PersistenceContext.class
    jar:file:/C:/Users/Asus/.m2/repository/org/hibernate/javax/persistence/hibernate-jpa-2.1-api/1.0.0.Final/hibernate-jpa-2.1-api-1.0.0.Final.jar!/javax/persistence/PersistenceContext.class

It was loaded from the following location:

    file:/C:/Users/Asus/.m2/repository/org/hibernate/javax/persistence/hibernate-jpa-2.0-api/1.0.1.Final/hibernate-jpa-2.0-api-1.0.1.Final.jar

Action:

Correct the classpath of your application so that it contains a single, compatible version of javax.persistence.PersistenceContext

Answer 1

首先在您的存储库中删除 maven 目录 hibernate，然后创建一个 maven clean install 以正确重新导入您的依赖项。 如果它仍然不能解决您的问题，请使用maven tree:dependency 来检测导入 hibernate-jpa-2.0-api 的依赖项并将其排除在您的 pom 中

Answer 2

有 4 个步骤可以做到这一点：

1. 您必须找到要删除的依赖项的位置，我认为您要删除 hibernate-jpa-2.0-api-1.0.1.Final.jar

   mvn dependency:tree
   

2. 当您找到位置时，您必须将 exclusions 放在加载不需要的依赖项的依赖项上，例如

   <dependency>
     ...
     <exclusions>
      <exclusion>
         <groupId>org.hibernate.javax.persistence</groupId>
         <artifactId>hibernate-jpa-2.0-api</artifactId>
         <version>1.0.1.Final</version>
      </exclusion>
    </exclusions>
   </dependency>
   

3. 在我的情况下，我清理我的项目，例如

   mvn clean
   

4. 您可以验证它是否已经存在mvn dependency:tree | grep hibernate-jpa-2.0-api

Answer 3

只需检查依赖树从项目依赖列表中删除依赖项中的jar

Answer 4

尝试转到.m2文件夹下的依赖加载位置，并删除特定文件夹hibernate-jpa-2.0-api

删除文件夹后，尝试执行 ma​​ven 全新安装。

构建项目并再次运行它。

之所以会出现是因为有两个版本

hibernate-jpa-2.0-api/1.0.0.Final/hibernate-jpa-2.0-api-1.0.1.Final.jar

hibernate-jpa-2.0-api/1.0.1.Final/hibernate-jpa-2.0-api-1.0.1.Final.jar

它应该只包含一个兼容的 javax.persistence.PersistenceContext 版本