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：

<dependency>
<groupId>org.codehaus.groovy</groupId>
<artifactId>groovy-all</artifactId>
<version>2.1.8</version>
</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

<jdbc:embedded-database id="dataSource" type="H2">
</jdbc:embedded-database>
<bean
class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"
id="entityManagerFactory">
<property name="persistenceUnitName" value="persistenceUnit" />
<property name="dataSource" ref="dataSource" />
<property name="persistenceProviderClass" value="org.hibernate.ejb.HibernatePersistence"></property>
<property name="packagesToScan">
<array>
<value>com.hantsylabs.example.spring.model</value>
</array>
</property>
<property name="jpaProperties">
<value>
hibernate.format_sql=true
hibernate.show_sql=true
hibernate.hbm2ddl.auto=create
</value>
</property>
</bean>
<bean class="org.springframework.orm.jpa.JpaTransactionManager"
id="transactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>

Annotation

@Configuration
@ComponentScan(basePackages = { "com.hantsylabs.example.spring.dao","com.hantsylabs.example.spring.jpa" })
@EnableTransactionManagement(mode=AdviceMode.ASPECTJ)
public class JpaConfig {
@Bean
public DataSource dataSource() {
return new EmbeddedDatabaseBuilder().setType(EmbeddedDatabaseType.H2).build();
}
@Bean
public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
LocalContainerEntityManagerFactoryBean emf = new LocalContainerEntityManagerFactoryBean();
emf.setDataSource(dataSource());
emf.setPackagesToScan("com.hantsylabs.example.spring.model");
emf.setPersistenceProvider(new HibernatePersistence());
emf.setJpaProperties(jpaProperties());
return emf;
}
private Properties jpaProperties() {
Properties extraProperties = new Properties();
extraProperties.put("hibernate.format_sql", "true");
extraProperties.put("hibernate.show_sql", "true");
extraProperties.put("hibernate.hbm2ddl.auto", "create");
return extraProperties;
}
@Bean
public PlatformTransactionManager transactionManager() {
return new JpaTransactionManager(entityManagerFactory().getObject());
}
}

Groovy DSL

import org.apache.commons.dbcp.BasicDataSource
import org.springframework.orm.jpa.JpaTransactionManager
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean
import com.hantsylabs.example.spring.jpa.JpaConferenceDaoImpl
beans {
dataSource(BasicDataSource) {
driverClassName = "org.h2.Driver"
url = "jdbc:h2:mem:spring4-sandbox"
username = "sa"
password = ""
}
entityManagerFactory(LocalContainerEntityManagerFactoryBean){
persistenceProviderClass="org.hibernate.ejb.HibernatePersistence"
dataSource=dataSource
persistenceUnitName="persistenceUnit"
packagesToScan=["com.hantsylabs.example.spring.model"]
jpaProperties=[
"hibernate.format_sql":"true",
"hibernate.show_sql":"true",
"hibernate.hbm2ddl.auto":"create"
]
}
transactionManager(JpaTransactionManager){
entityManagerFactory=entityManagerFactory
}
conferenceDao(JpaConferenceDaoImpl){
}
}

巴特西

spring4.0之八：Groovy DSL

XML

Annotation

Groovy DSL

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