Guice 3.0 学习 persist jpa
guice 3.0 的 persist 实现 使用的是 jpa
代码可以从 googlecode 上面下载
http://code.google.com/p/google-guice/downloads/list
guice-3.0-rc3-src.zip
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
<?xml version="1.0" encoding="UTF-8" ?><persistence 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" version="1.0"> <!-- JPA test "unit" --> <persistence-unit name="testUnit" transaction-type="RESOURCE_LOCAL"><provider>org.hibernate.ejb.HibernatePersistence</provider> <class>com.google.inject.persist.jpa.JpaTestEntity</class> <class>com.google.inject.persist.jpa.JpaParentTestEntity</class> <exclude-unlisted-classes>true</exclude-unlisted-classes> <properties> <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/> <property name="hibernate.connection.url" value="jdbc:hsqldb:mem:persistence"/> <property name="hibernate.connection.username" value="sa"/> <property name="hibernate.connection.password" value=""/> <property name="hibernate.connection.pool_size" value="2"/> <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/> <property name="hiberante.cache_provider" value="org.hibernate.cache.NoCacheProvider"/> <property name="hibernate.hbm2ddl.auto" value="create"/> </properties> </persistence-unit></persistence>
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 @GeneratedValuepublic 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;}@Overridepublic 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;}@Overridepublic 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.<Properties>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。
页:
[1]