spring4.0之八：Groovy DSL

4.0的一个重要特征就是完全支持Groovy，Groovy是Spring主导的一门基于JVM的脚本语言（动态语言）。在spring 2.x，脚本语言通过 Java scripting engine在Spring中得到支持。而在4.0中，Groovy的变得更重要，Groovy可以替换xml和注解用来作为bean配置。

要使用Groovy，首先用maven下载Groovy的包，pom.xml文件中添加：

1. <dependency>
2. <groupId>org.codehaus.groovy</groupId>
3. <artifactId>groovy-all</artifactId>
4. <version>2.1.8</version>
5. </dependency>

下面使用xml，java annotation，groovy dsl实现相同功能的不同配置方式比较

XML

1. <jdbc:embedded-database id="dataSource" type="H2">
2. </jdbc:embedded-database>
3. <bean
4. class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"
5. id="entityManagerFactory">
6. <property name="persistenceUnitName" value="persistenceUnit" />
7. <property name="dataSource" ref="dataSource" />
8. <property name="persistenceProviderClass" value="org.hibernate.ejb.HibernatePersistence"></property>
9. <property name="packagesToScan">
10. <array>
11. <value>com.hantsylabs.example.spring.model</value>
12. </array>
13. </property>
14. <property name="jpaProperties">
15. <value>
16. hibernate.format_sql=true
17. hibernate.show_sql=true
18. hibernate.hbm2ddl.auto=create
19. </value>
20. </property>
21. </bean>
22. <bean class="org.springframework.orm.jpa.JpaTransactionManager"
23. id="transactionManager">
24. <property name="entityManagerFactory" ref="entityManagerFactory" />
25. </bean>

Annotation

1. @Configuration
2. @ComponentScan(basePackages = { "com.hantsylabs.example.spring.dao","com.hantsylabs.example.spring.jpa" })
3. @EnableTransactionManagement(mode=AdviceMode.ASPECTJ)
4. public class JpaConfig {
5. @Bean
6. public DataSource dataSource() {
7. return new EmbeddedDatabaseBuilder().setType(EmbeddedDatabaseType.H2).build();
8. }
9. @Bean
10. public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
11. LocalContainerEntityManagerFactoryBean emf = new LocalContainerEntityManagerFactoryBean();
12. emf.setDataSource(dataSource());
13. emf.setPackagesToScan("com.hantsylabs.example.spring.model");
14. emf.setPersistenceProvider(new HibernatePersistence());
15. emf.setJpaProperties(jpaProperties());
16. return emf;
17. }
18. private Properties jpaProperties() {
19. Properties extraProperties = new Properties();
20. extraProperties.put("hibernate.format_sql", "true");
21. extraProperties.put("hibernate.show_sql", "true");
22. extraProperties.put("hibernate.hbm2ddl.auto", "create");
23. return extraProperties;
24. }
25. @Bean
26. public PlatformTransactionManager transactionManager() {
27. return new JpaTransactionManager(entityManagerFactory().getObject());
28. }
29. }

Groovy DSL

1. import org.apache.commons.dbcp.BasicDataSource
2. import org.springframework.orm.jpa.JpaTransactionManager
3. import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean
4. import com.hantsylabs.example.spring.jpa.JpaConferenceDaoImpl
5. beans {
6. dataSource(BasicDataSource) {
7. driverClassName = "org.h2.Driver"
8. url = "jdbc:h2:mem:spring4-sandbox"
9. username = "sa"
10. password = ""
11. }
12. entityManagerFactory(LocalContainerEntityManagerFactoryBean){
13. persistenceProviderClass="org.hibernate.ejb.HibernatePersistence"
14. dataSource=dataSource
15. persistenceUnitName="persistenceUnit"
16. packagesToScan=["com.hantsylabs.example.spring.model"]
17. jpaProperties=[
18. "hibernate.format_sql":"true",
19. "hibernate.show_sql":"true",
20. "hibernate.hbm2ddl.auto":"create"
21. ]
22. }
23. transactionManager(JpaTransactionManager){
24. entityManagerFactory=entityManagerFactory
25. }
26. conferenceDao(JpaConferenceDaoImpl){
27. }
28. }