【发布时间】：2011-07-25 11:17:25
【问题描述】：
我继承了一个 Spring 3 应用程序，该应用程序使用 XML 文件来定义和连接 bean。我知道从 Spring 2 开始，这些大部分都可以用注释替换。我希望 Spring 能够：
- 通过扫描某些包中的类来检测 bean，其中包含用于指示 Spring bean 的任何注释
- 尝试在我用相关注释标记的 bean 中按名称和字段自动装配
我需要采取哪些步骤来实现这一目标？
【问题讨论】：
【发布时间】：2011-07-25 11:17:25
【问题描述】：
我会给你一个xml配置，它分别对应基于注解的配置，这样你就可以很容易地看到如何将你的bean从xml更改为java，反之亦然
`<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-4.0.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd">
<context:component-scan base-package="com.mycompany.backendhibernatejpa.controller" />
<mvc:annotation-driven />
<bean id="iAbonneDao" class="com.mycompany.backendhibernatejpa.daoImpl.AbonneDaoImpl"/>
<bean id="iAbonneService" class="com.mycompany.backendhibernatejpa.serviceImpl.AbonneServiceImpl"/>
<!-- couche de persistance JPA -->
<bean id="entityManagerFactory"
class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
<property name="databasePlatform" value="org.hibernate.dialect.MySQL5InnoDBDialect" />
<property name="generateDdl" value="true" />
<property name="showSql" value="true" />
</bean>
</property>
<property name="loadTimeWeaver">
<bean
class="org.springframework.instrument.classloading.InstrumentationLoadTimeWeaver" />
</property>
</bean>
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="locations" value="classpath:bd.properties"/>
</bean>
<!-- la source de donnéees DBCP -->
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close" >
<property name="driverClassName" value="${bd.driver}" />
<property name="url" value="${bd.url}" />
<property name="username" value="${bd.username}" />
<property name="password" value="${bd.password}" />
</bean>
<!-- le gestionnaire de transactions -->
<bean id="txManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>
<!-- traduction des exceptions -->
<bean class="org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor" />
<!-- annotations de persistance -->
<bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />
</beans>`
这个文件被命名为 springrest-sevlet。其实你可以给名字 您希望后跟“-servlet”并在文件中提及该名称 web.xml
` <web-app>
<display-name>Gescable</display-name>
<servlet>
<servlet-name>springrest</servlet-name>
<servlet-class> org.springframework.web.servlet.DispatcherServlet </servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>springrest</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>`
这两个文件应该放在文件夹“WEB-INF”中。 现在等效于基于注释的配置
`/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package com.mycompany.backendhibernatejpaannotation.configuration;
import com.mycompany.backendhibernatejpaannotation.daoImpl.AbonneDaoImpl;
import com.mycompany.backendhibernatejpaannotation.daoInterface.IAbonneDao;
import com.mycompany.backendhibernatejpaannotation.serviceImpl.AbonneServiceImpl;
import com.mycompany.backendhibernatejpaannotation.serviceInterface.IAbonneService;
import javax.sql.DataSource;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor;
import org.springframework.instrument.classloading.InstrumentationLoadTimeWeaver;
import org.springframework.jdbc.datasource.DriverManagerDataSource;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
/**
*
* @author vivien saa
*/
@Configuration
@EnableWebMvc
@ComponentScan(basePackages = "com.mycompany.backendhibernatejpaannotation")
public class RestConfiguration {
@Bean
public IAbonneDao iAbonneDao() {
return new AbonneDaoImpl();
}
@Bean
public IAbonneService iAbonneService() {
return new AbonneServiceImpl();
}
// @Bean
// public PropertyPlaceholderConfigurer placeholderConfigurer() {
// PropertyPlaceholderConfigurer placeholderConfigurer = new PropertyPlaceholderConfigurer();
// placeholderConfigurer.setLocations("classpath:bd.properties");
// return placeholderConfigurer;
// }
@Bean
public DataSource dataSource() {
DriverManagerDataSource dataSource = new DriverManagerDataSource();
dataSource.setDriverClassName("com.mysql.jdbc.Driver");
dataSource.setUrl("jdbc:mysql://localhost:3306/gescable");
dataSource.setUsername("root");
dataSource.setPassword("root");
return dataSource;
}
@Bean
public HibernateJpaVendorAdapter jpaVendorAdapter() {
HibernateJpaVendorAdapter jpaVendorAdapter = new HibernateJpaVendorAdapter();
jpaVendorAdapter.setDatabasePlatform("org.hibernate.dialect.MySQL5InnoDBDialect");
jpaVendorAdapter.setGenerateDdl(true);
jpaVendorAdapter.setShowSql(true);
return jpaVendorAdapter;
}
@Bean
public InstrumentationLoadTimeWeaver loadTimeWeaver() {
InstrumentationLoadTimeWeaver loadTimeWeaver = new InstrumentationLoadTimeWeaver();
return loadTimeWeaver;
}
@Bean
public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
LocalContainerEntityManagerFactoryBean entityManagerFactory = new LocalContainerEntityManagerFactoryBean();
entityManagerFactory.setDataSource(dataSource());
entityManagerFactory.setJpaVendorAdapter(jpaVendorAdapter());
entityManagerFactory.setLoadTimeWeaver(loadTimeWeaver());
return entityManagerFactory;
}
@Bean
public JpaTransactionManager jpaTransactionManager() {
JpaTransactionManager jpaTransactionManager = new JpaTransactionManager();
jpaTransactionManager.setEntityManagerFactory(entityManagerFactory().getObject());
return jpaTransactionManager;
}
@Bean
public PersistenceExceptionTranslationPostPro`enter code here`cessor persistenceExceptionTranslationPostProcessor() {
return new PersistenceExceptionTranslationPostProcessor();
}
@Bean
public PersistenceAnnotationBeanPostProcessor persistenceAnnotationBeanPostProcessor() {
return new PersistenceAnnotationBeanPostProcessor();
}
}`
这个文件必须有这个文件
`
package com.mycompany.backendhibernatejpaannotation.configuration;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;
/**
*
* @author vivien saa
*/
public class Initializer extends AbstractAnnotationConfigDispatcherServletInitializer {
@Override
protected Class<?>[] getRootConfigClasses() {
return new Class[]{RestConfiguration.class};
}
@Override
protected Class<?>[] getServletConfigClasses() {
return null;
}
@Override
protected String[] getServletMappings() {
return new String[]{"/"};
}
}
`
【讨论】：
TL;DR 版本是您需要将 <context:annotation-config/> 添加到您的 spring 配置中，然后使用 @Component 注释您的 bean，并在您的属性设置器中使用 @Autowired 注释
【讨论】：
-
只是补充 CarlosZ 的回答。如果您正在创建一个新组件并且想要自动装配一些 bean，您不必创建 getter 和 setter，只需将 @Autowired 注释添加到属性声明中，您就可以开始了。
-
正确@Lucas，您可以进行setter注入、属性注入（不需要setter）或构造函数注入（我个人最喜欢的，因为我认为在调用构造函数时应该完全初始化对象，包括依赖项）。
我认为首先要做的就是慢慢来。一次只选择一项服务并迁移它，因为您有理由接触它。使用大量的 spring 配置是一种肯定的方式，在生产中你只需要偶尔需要一次依赖。
【讨论】：