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guice 3.0 的 persist 实现 使用的是 jpa 

代码可以从 googlecode 上面下载 

现在还是 beate的版本 但是可以 看api 学习了。

首先 测试使用的是 hsqldb 数据库

jpa 的配置 文件 test/META-INF/persistence.xml

   
       
        
    		
     
      org.hibernate.ejb.HibernatePersistence
                     
     
      com.google.inject.persist.jpa.JpaTestEntity
             
     
      com.google.inject.persist.jpa.JpaParentTestEntity
             
     
      true
             
                 
                  
                  
                  
                  
                  
                  
                  
              
         
    
   

实体类

/** * Copyright (C) 2010 Google, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */package com.google.inject.persist.jpa;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.Id;/** @author Dhanji R. Prasanna (dhanji@gmail.com) */@Entitypublic class JpaTestEntity {  private Long id;  private String text;  @Id @GeneratedValue  public Long getId() {    return id;  }  public void setId(Long id) {    this.id = id;  }  public String getText() {    return text;  }  public void setText(String text) {    this.text = text;  }  @Override  public boolean equals(Object o) {    if (this == o) {      return true;    }    if (o == null || getClass() != o.getClass()) {      return false;    }    JpaTestEntity that = (JpaTestEntity) o;    if (id != null ? !id.equals(that.id) : that.id != null) {      return false;    }    if (text != null ? !text.equals(that.text) : that.text != null) {      return false;    }    return true;  }  @Override  public int hashCode() {    int result = id != null ? id.hashCode() : 0;    result = 31 * result + (text != null ? text.hashCode() : 0);    return result;  }}

测试的方法

public static class TransactionalObject {    private final EntityManager em;    @Inject    public TransactionalObject(EntityManager em) {      this.em = em;    }    @Transactional    public void runOperationInTxn() {      JpaTestEntity entity = new JpaTestEntity();      entity.setText(UNIQUE_TEXT);      em.persist(entity);    }    @Transactional    public JpaTestEntity runOperationInTxnWithMerge() {      JpaTestEntity entity = new JpaTestEntity();      entity.setText(UNIQUE_TEXT_MERGE);      return em.merge(entity);    }    @Transactional(rollbackOn = IOException.class)    public void runOperationInTxnThrowingChecked() throws IOException {      JpaTestEntity entity = new JpaTestEntity();      entity.setText(TRANSIENT_UNIQUE_TEXT);      em.persist(entity);      throw new IOException();    }    @Transactional    public void runOperationInTxnThrowingUnchecked() {      JpaTestEntity entity = new JpaTestEntity();      entity.setText(TRANSIENT_UNIQUE_TEXT);      em.persist(entity);      throw new IllegalStateException();    }  }

 在 一个事物 拦截的地方 用@Transactional 标记 其中 EntityManager em; 通过构造 创建

JpaPersistModule extends PersistModule 这个 在 src 目录 下。也就是在 guice3.0 的jar 里面。

private Properties properties;  private MethodInterceptor transactionInterceptor;  @Override protected void configurePersistence() {    bindConstant().annotatedWith(Jpa.class).to(jpaUnit);    if (null != properties) {      bind(Properties.class).annotatedWith(Jpa.class).toInstance(properties);    } else {      bind(Properties.class).annotatedWith(Jpa.class)          .toProvider(Providers.
   
    of(null));    }    bind(JpaPersistService.class).in(Singleton.class);    bind(PersistService.class).to(JpaPersistService.class);    bind(UnitOfWork.class).to(JpaPersistService.class);    bind(EntityManager.class).toProvider(JpaPersistService.class);    bind(EntityManagerFactory.class)        .toProvider(JpaPersistService.EntityManagerFactoryProvider.class);    transactionInterceptor = new JpaLocalTxnInterceptor();    requestInjection(transactionInterceptor);    // Bind dynamic finders.    for (Class
     finder : dynamicFinders) {      bindFinder(finder);    }  }
   

 其中 那个 finder 没有明白。。

其中 

bind(JpaPersistService.class).in(Singleton.class);    bind(PersistService.class).to(JpaPersistService.class);    bind(UnitOfWork.class).to(JpaPersistService.class);    bind(EntityManager.class).toProvider(JpaPersistService.class);    bind(EntityManagerFactory.class)        .toProvider(JpaPersistService.EntityManagerFactoryProvider.class);

就是 帮定了 jpa的 类。初始化了事物，和事物工厂类。

附件 是 官方的 jpa的 测试 代码。

jpa 的 实现用的 是 hibernate 。

等 guice 3.0 正式发布了 打算 将现在的工程 修改下。。变成 struts2+guice3+jpa这样的实现。

好处就是启动快。。运行快。。调试，开发 的方便。

而且 代码也少很多了。 

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