Spring 基于注解的配置（一）（@Conmponent ，@Repository，@Service，以及对访问资源的限定）

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基于java的Bean配置的自动装配

从Spring3.0开始通过java注解定义Bean：

@Conmponent 一个通用注解，可用于任何Bean(下面三个为其子注解)

@Repository :注解持久化类

@Service:注解服务层类

@Controller:注解控制层类（通常在Spring MVC中使用）

其他注解：

@Required

@Autowired

@Qualifier

@Resource

元注解：一个简单的注解可以应用到另外一个注解（由Spring提供的可以作为自己代码的注解）

Spring可以检测到类并将其注册到上下文ApplicationContext中

类的自动检测：
<context:component-scanbase-package="com"/>
<context:annotation-config></context:annotation-config>

过滤器进行自定义扫描：

类被发现并注册bean的条件：使用@Conmponent @Repository @Service@Controller注解或者使用@Conmponent自定义的注解

通过过滤器修改上面的行为：（regex通配符）

<context:component-scanbase-package="com">

<context:include-filtertype="regex"expression=".*Stub.*Repository"/>
<context:include-filtertype="annotation"expression="org.springframework.stereotype.Repository"/>
</context:component-scan>

还可以使用use-default-filters=”false”禁用自动发现与注册

定义Bean:

Bean名称由BeanNameGenerator生成（@Conmponent @Repository @Service@Controller可以显式设置Bean）

示例一：工程结构图：

ComponentTest.java

package com.spring.Component;

import org.springframework.stereotype.Component;

/**
* Created by ruanjianlin on 2017/10/5.
*/
@Component("component")
public class ComponentTest {

}

(单元测试)ComponentTestTest.java（通过注解对bean进行命名）

package com.spring.Component;

import com.spring.Repository.RepositoryImpIements;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.FileSystemXmlApplicationContext;

import static org.junit.Assert.*;

/**
* Created by ruanjianlin on 2017/10/6.
*/
public class ComponentTestTest {

    @Test
    public void testComponentAnnotation(){
        ApplicationContext app=newFileSystemXmlApplicationContext("路径+Annotation-test.xml");
        ComponentTest componentTest=(ComponentTest)app.getBean("component");

    }
}

ControllerDemo.java

package com.spring.controller;

import org.springframework.stereotype.Controller;

/**
* Created by ruanjianlin on 2017/10/5.
*/
@Controller
public class ControllerDemo {
    public voidexecute(){
        System.out.println("Controller annotation test");
    }

}

（单元测试）ControllerDemoTest.java

package com.spring.controller;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.FileSystemXmlApplicationContext;

import static org.junit.Assert.*;

/**
* Created by ruanjianlin on 2017/10/6.
*/
public class ControllerDemoTest {
    @Test
    public voidexecute()throwsException {
        ApplicationContext app=newFileSystemXmlApplicationContext("自己的路径+Annotation-test.xml");
        ControllerDemo con=( ControllerDemo)app.getBean("controllerDemo");
        con.execute();
    }

}

RepositoryInterface.java

package com.spring.Repository;

/**
* Created by ruanjianlin on 2017/10/5.
*/
public interface RepositoryInterface {
voidsave();
}

RepositoryImplements.java(实现上面的接口)

package com.spring.Repository;

import org.springframework.stereotype.Repository;

/**
* Created by ruanjianlin on 2017/10/5.
*/
@Repository
public class RepositoryImpIementsimplementsRepositoryInterface {
    public voidsave() {
        System.out.println("Repository annotation test");
    }
}

ServiceDemo,java

package com.spring.service;

import org.springframework.stereotype.Service;

/**
* Created by ruanjianlin on 2017/10/5.
*/
@Service
public class ServiceDemo {
    public voidaddUser(){
        System.out.println("service annotation test");
    }

}

其他有关的junit测试代码请自己仿照上面的例子进行编写

Annotation-test.xml

<?xml version="1.0"encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <context:component-scanbase-package="com.spring">
    </context:component-scan>

</beans>

注：。若在类定义中添加注解时未指定Bean id则Spring将按照默认命名进行注册，名字是它的类名第一个字符小写例如：ControllerDemo通过Controller注解注册时默认的注解名是controllerDemo，也可以自己指定

补充：

（1）通过resource-pattern指定扫描的资源

<context:component-scan base-package="com.spring"resource-pattern="Repository/*.class">
</context:component-scan>

运行结果：

controllerDemoTest:

org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'controllerDemo' is defined

Process finished with exit code -1

RepositoryImpIementsTest:

Process finished with exit code 0

由上面的运行结果可以判定resource-pattern作用即指定访问资源

排除特定的注解 exclude-filter expression输入排除的注解

<context:component-scanbase-package="package com.spring">
<context:exclude-filtertype="annotation"expression="org.springframework.stereotype.Repository"/>
</context:component-scan>

调用相关注解注册的Bean时产生的异常：

org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'repositoryImpIements' is defined

指定特定的注解 include-filter

<context:component-scanbase-package="package com.spring"use-default-filters="false">
<context:include-filtertype="annotation"expression="org.springframework.stereotype.Repository"/>
</context:component-scan>

调用其指定的注解注册的Bean:

Process finished with exit code 0

调用无关的Bean:

org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'controllerDemo' is defined

use-default-filters默认为true扫描包下的所有注解

<context:include-filter>和<context:exclude-filter>子节点支持多种类型的过滤表达式（即type的取值）：

类别

示例

说明

annotation

org.springframework.stereotype.

xxAnnotation

所有标注了XxxAnnotation的类，该类型采用目标类是否标注了某个注解进行过滤

assinable

com.spring.XxxService

所有继承或扩展XxxService的类，该类型采用了目标类是否继承或扩展某个特定类进行过滤

aspectj

com.spring.*Service

所有类名义Service结束的类及继承或扩展它们的类，该类型采用AspectJ表达式进行过滤

regex

com.spring.anno.*

所有com.spring.anno包下的类。该类型采用正则表达式，根据类的类名进行过滤

custom

com.spring.XxxTypeFilter

自定义过滤器，采用XxxTypeFilter通过代码的方式（自己建立的过滤器）定义过滤原则。该类必须实现org.springframework

Regex使用示例：

<context:component-scanbase-package="com.spring"use-default-filters="false">
<context:include-filtertype="regex"expression="com.spring.Repository.*"/>
</context:component-scan>

assinable使用示例：

<context:component-scanbase-package="com.spring"use-default-filters="false">
<context:include-filtertype="assignable"expression="com.spring.Repository.RepositoryInterface"/>
</context:component-scan>

调用没有实现相关继承时控制台的输出：

org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'controllerDemo' is defined

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