10

一直在尝试一整天，并在网上搜索了 **** ......徒劳无功。你是我最后的希望：

这是我的代码：

实体：

package sas.test.model;

import javax.persistence.Entity;
import javax.persistence.Id;

@Entity
public class Employee {
    @Id private int id;
    private String name;
    private long salary;
    public Employee() {}
    public Employee(int id) { this.id = id; }
    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 long getSalary() { return salary; }
    public void setSalary (long salary) { this.salary = salary; }
}

服务等级：

package sas.test.dao;

import sas.test.model.Employee;

import javax.persistence.*;
import java.util.List;

public class EmployeeService {

    protected EntityManager em;

    public EmployeeService(EntityManager em) {
        this.em = em;
    }
    public Employee createEmployee(int id, String name, long salary) {
        Employee emp = new Employee(id);

      emp.setName(name);
  emp.setSalary(salary);
  em.persist(emp);
  return emp;
}
  public void removeEmployee(int id) {
      Employee emp = findEmployee(id);
      if (emp != null) {
          em.remove(emp);
      }
  }
  public Employee raiseEmployeeSalary(int id, long raise) {
      Employee emp = em.find(Employee.class, id);
      if (emp != null) {
          emp.setSalary(emp.getSalary() + raise);
      }
      return emp;
  }
  public Employee findEmployee(int id) {
      return em.find(Employee.class, id);
  }

}

主要课程：

package sas.test.main;

import javax.persistence.*;
import java.util.List;
import sas.test.model.Employee;
import sas.test.dao.EmployeeService;


public class ExecuteMe {
    public static void main(String[] args) {
        EntityManagerFactory emf =
                Persistence.createEntityManagerFactory("EmployeeService");
        EntityManager em = emf.createEntityManager();
        EmployeeService service = new EmployeeService(em);

          // create and persist an employee
          em.getTransaction().begin();
          Employee emp = service.createEmployee(158, "John Doe", 45000);
          em.getTransaction().commit();
          System.out.println("Persisted " + emp);
          // find a specific employee
          emp = service.findEmployee(158);
          System.out.println("Found " + emp);
          // find all employees
     //     List<Employee> emps = service.findAllEmployees();
         // for (Employee e : emps)
         //      System.out.println("Found employee: " + e);
          // update the employee
          em.getTransaction().begin();
          emp = service.raiseEmployeeSalary(158, 1000);
          em.getTransaction().commit();
          System.out.println("Updated " + emp);
          // remove an employee
          em.getTransaction().begin();
          service.removeEmployee(158);
          em.getTransaction().commit();
          System.out.println("Removed Employee 158");
          // close the EM and EMF when done
          em.close();
          emf.close();
    }
}

最后我的confs。

pom.xml：

<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>Test_JPA_CRUD</groupId>
    <artifactId>Test_JPA_CRUD</artifactId>
    <packaging>jar</packaging>
    <version>1.0</version>
    <name>Test_JPA_CRUD</name>
    <url>http://maven.apache.org</url>
    <repositories>


        <repository>
            <id>maven2-repository.dev.java.net</id>
            <name>Java.net Repository for Maven</name>
            <url>http://download.java.net/maven/2/
            </url>
            <layout>default</layout>
        </repository>


        <repository>
            <id>maven.org</id>
            <name>maven.org Repository</name>
            <url>http://repo1.maven.org/maven2</url>
            <releases>
                <enabled>true</enabled>
            </releases>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </repository>
    </repositories>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.8.1</version>
            <scope>test</scope>
        </dependency>

        <!--

                <dependency>
                    <groupId>javax</groupId>
                    <artifactId>javaee-api</artifactId>
                    <version>6.0</version>
                </dependency>
        -->
        <!--
        <dependency>
            <groupId>javax.persistence</groupId>
            <artifactId>persistence-api</artifactId>
            <version>1.0</version>
        </dependency>
                                      -->
        <!-- JPA2 provider -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
            <version>3.4.0.GA</version>
        </dependency>

        <!-- JDBC driver -->
        <dependency>
            <groupId>org.apache.derby</groupId>
            <artifactId>derby</artifactId>
            <version>10.5.3.0_1</version>
        </dependency>


        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>3.3.2.GA</version>
        </dependency>
        <dependency>
          <groupId>org.hibernate</groupId>
          <artifactId>ejb3-persistence</artifactId>
          <version>3.3.2.Beta1</version>
        </dependency>

        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-annotations</artifactId>
            <version>3.4.0.GA</version>
        </dependency>

        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.5.2</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.14</version>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <!-- compile with mvn assembly:assembly -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>2.2</version>
            </plugin>
            <!-- compile with mvn assembly:assembly -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-assembly-plugin</artifactId>
                <version>2.2-beta-2</version>
                <configuration>
                    <descriptorRefs>
                        <descriptorRef>jar-with-dependencies</descriptorRef>
                    </descriptorRefs>
                    <archive>
                        <manifest>
                            <mainClass>sas.test.main.ExecuteMe</mainClass>
                        </manifest>
                    </archive>
                </configuration>
                <executions>
                    <execution>
                        <phase>package</phase>
                    </execution>
                </executions>
            </plugin>
            <plugin>
                <!-- Force UTF-8 & Java-Version 1.6 -->
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.6</source>
                    <target>1.6</target>
                    <!--<encoding>utf-8</encoding>-->
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

我保证，persistence.xml 位于目标的类路径中：

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="1.0"
             xmlns="http://java.sun.com/xml/ns/persistence"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd
http://java.sun.com/xml/ns/persistence ">
    <persistence-unit name="EmployeeService" transaction-type="RESOURCE_LOCAL">
        <provider>org.hibernate.ejb.HibernatePersistence</provider>
        <class>sas.test.model.Employee</class>
        <properties>

            <property name="javax.persistence.jdbc.driver" value="org.apache.derby.jdbc.EmbeddedDriver"/>
            <property name="hibernate.dialect" value="org.hibernate.dialect.DerbyDialect"/>
            <property name="hibernate.show_sql" value="true"/>
            <property name="javax.persistence.jdbc.url" value="jdbc:derby:webdb;create=true"/>


        </properties>
    </persistence-unit>
</persistence>

正如您可能从一些注释代码中注意到的那样，我尝试了 JPA2.0 的 Hibernate 和 J2EE 6 实现，但是都失败了。上述代码最终出现以下错误：

log4j:WARN No appenders could be found for logger (org.hibernate.cfg.annotations.Version).
log4j:WARN Please initialize the log4j system properly.
Exception in thread "main" java.lang.UnsupportedOperationException: The user must supply a JDBC connection
 at org.hibernate.connection.UserSuppliedConnectionProvider.getConnection(UserSuppliedConnectionProvider.java:54)
 at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:446)
 at org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:167)
 at org.hibernate.jdbc.JDBCContext.connection(JDBCContext.java:142)

知道出了什么问题吗？任何实际运行的“Hello World”maven/JPA2 演示？我无法运行谷歌搜索提供的任何内容。

提前谢谢。

4

3 回答 3

18

Hibernate EntityManager 3.4.0.GA is not a JPA 2.0 implementation so it won't support the standardized javax.persistence.* properties in the persistence.xml (hence the exception about no JDBC connection being supplied). For JPA 2.0, you need Hibernate EM 3.5.1-Final. Below a simple POM with the right dependency:

<project>
  ...
  <repositories>
    <repository>
      <id>jboss</id>
      <name>JBoss repository</name>
      <url>http://repository.jboss.org/maven2</url>
    </repository>
  </repositories>

  <dependencies>
    <!-- JPA API and Hibernate -->
    <dependency>
      <groupId>org.hibernate</groupId>
      <artifactId>hibernate-entitymanager</artifactId>
      <version>3.5.1-Final</version>
    </dependency>

    <!-- Logging -->
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-simple</artifactId>
      <version>1.5.8</version>
    </dependency>

    ...
  </dependencies>
  ...
</project>

And that's all you need, other dependencies will be pulled transitively. Just replace the slf4j binding I'm using with your favorite one.

If you want to use Bean Validation (JSR-303) API and the RI, add (adapt the scope to suit your needs):

<!-- Bean Validation API and RI -->
<dependency>
    <groupId>javax.validation</groupId>
    <artifactId>validation-api</artifactId>
    <version>1.0.0.GA</version>
    <scope>compile</scope>
</dependency>
<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-validator</artifactId>
    <version>4.0.2.GA</version>
    <scope>runtime</scope>
</dependency>

I didn't test your code but this will at least fix your POM.

PS: You don't need to specify the persistence provider in your persistence.xml if there is only one on the classpath, you don't need to specify the dialect. But this shouldn't hurt.

PPS: Note that javax.persistence:persistence-api:jar:1.0 is an API, not an implementation, it won't do anything by itself (I mean, it's not a replacement for Hibernate, EclipseLink, etc).

于 2010-04-22T22:54:07.630 回答
3

如果你没有使用 Maven 依赖并且只使用了 eclipse 类路径设置，你只需要将上面的 jar 文件放在 hibernate 3.5 及以上版本的类路径中

1）休眠核心Jar

2）休眠注释jar

3) jboss 日志记录罐

4）休眠实体管理器jar

JPA API 2. jar（它包含在 hibernate 发行版中）。

我有类似的问题，我使用了这种方法并且它有效。从同一版本的发行版中获取所有依赖的 jar 是最好的主意。如果您发现任何错误，您可以从日志中找到它并继续将 jar 放入类路径中

于 2011-10-30T05:29:26.437 回答
0

我在我的前任中没有发现的一件重要的事情没有提到，但似乎至关重要的是添加到休眠依赖提供的范围。因此，不会添加这些导致的战争/耳朵。

<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-entitymanager</artifactId>
    <version>3.5.1-Final</version>
    <scope>provided</scope>
</dependency>

我花了一段时间才发现这一点，所以我为其他人指出了这一点。

于 2011-02-23T11:30:33.630 回答