基础配置
- 启用组件扫描配置
Java类配置文件方式
package com.springapp.mvc.application;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
/**
* Created by xuc on 2018/1/7.
* 配置类
*/
@ComponentScan(basePackages = {"com.springapp.mvc"})
@Configuration
public class Application {
}
注：此处@Configuration为声明该类为配置文件类，@ComponentScan为声明开启扫描功能，若未配置基础包属性，则默认扫描该配置类所在当前包，否则扫描基础包定义的包
xml文件配置
<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-scan base-package="com.springapp.mvc"/>
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/pages/"/>
<property name="suffix" value=".jsp"/>
</bean>
</beans>
- 手动装配bean
在大部分情况下我们都是使用组件扫描的的方式来装载bean，但有时候在使用第三方框架时，需要指定某些配置类，这种情况下通过手动配置则更加合适
Java类装配方式
package com.springapp.mvc.application;
import com.springapp.mvc.easyBean.Braves;
import com.springapp.mvc.easyBean.Sword;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
/**
* Created by xuc on 2018/1/7.
* 配置类
*/
@ComponentScan(basePackages = {"com.springapp.mvc"})
@Configuration
public class Application {
@Bean(name = "braves")
public Braves braves() {
return new Braves(sword());
}
@Bean
public Braves braves1() {
Braves braves = new Braves();
braves.setSword(sword());
return braves;
}
@Bean
public Sword sword() {
return new Sword();
}
}
注：此处首先声明配置文件类，再通过在方法上@Bean注解，则spring将知道该方法会返回一个bean且注册到spring上下文中。@Bean注解若配置name属性，则Bean的ID为该值，否则默认和方法名一样。braves( ) 和braves1( ) 方法分别实现了构造函数注入和set方式注入
xml文件配置方式
<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-scan base-package="com.springapp.mvc"/>
<bean class="com.springapp.mvc.easyBean.Sword" id="sword"></bean>
<bean class="com.springapp.mvc.easyBean.Braves" id="braves">
<constructor-arg ref="sword"></constructor-arg>
</bean>
<bean class="com.springapp.mvc.easyBean.Braves" id="braves1">
<property name="sword" ref="sword"></property>
</bean>
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/pages/"/>
<property name="suffix" value=".jsp"/>
</bean>
</beans>
braves bean 和 braves1 bean分别实现了构造函数注入和set方式注入.
- Java类和xml文件混合配置（单或多）
Java类配置
package com.springapp.mvc.application;
import com.springapp.mvc.easyBean.Sword;
import org.springframework.context.annotation.*;
/**
* Created by xuc on 2018/1/7.
* 配置类
*/
@ComponentScan(basePackages = {"com.springapp.mvc"})
@Configuration
@Import(Application1.class)
@ImportResource("classpath:mvc-dispatcher-servlet.xml")
public class Application {
@Bean
public Sword sword() {
return new Sword();
}
}
注：此处@Import 注解为导入配置java类，@ImportResource注解为导入配置xml文件，此处可配置多个，通过都好隔开
xml文件配置
<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-scan base-package="com.springapp.mvc"/>
<import resource="mvc-dispatcher-servlet1.xml"></import>
<bean class="com.springapp.mvc.application.Application"></bean>
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/pages/"/>
<property name="suffix" value=".jsp"/>
</bean>
</beans>
条件配置
- spring profile 实现跨环境配置
1.配置profile bean
java类配置
package com.springapp.mvc.application;
import ...
/**
* Created by xuc on 2018/1/7.
* 配置类
*/
@ComponentScan(basePackages = {"com.springapp.mvc"})
@Configuration
public class Application {
@Bean
public Braves braves(IArms arms){
return new Braves(arms);
}
@Bean
@Profile("dev")
public Sword sword() {
return new Sword();
}
@Bean
@Profile("test")
public Machete machete(){
return new Machete();
}
}
注：通过@Profile注解声明该bean属于哪种环境下的（常见于数据库连接操作）
xml文件配置
<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-scan base-package="com.springapp.mvc"/>
<beans profile="dev">
<bean class="com.springapp.mvc.easyBean.Sword"></bean>
</beans>
<beans profile="test">
<bean class="com.springapp.mvc.easyBean.Machete"></bean>
</beans>
<beans>
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/pages/"/>
<property name="suffix" value=".jsp"/>
</bean>
</beans>
</beans>
2.激活spring profile
<web-app version="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<display-name>Spring MVC Application</display-name>
<context-param>
<param-name>spring.profiles.default</param-name>
<param-value>dev</param-value>
</context-param>
<servlet>
<servlet-name>mvc-dispatcher</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>spring.profiles.default</param-name>
<param-value>dev</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>mvc-dispatcher</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
注：在web应用中，只需配置spring.profiles.default 或 spring.profiles.active，前者为默认后者为激活
3.测试一下
在配置“dev”的情况下，只会有sword bean存在，使用machete bean则会报类不存在异常！
- condition实现条件注册bean
定义一个实现condition接口的类，实现matches( )方法，在方法里面做校验判断
package com.springapp.mvc.application;
import org.springframework.context.annotation.Condition;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.core.env.Environment;
import org.springframework.core.type.AnnotatedTypeMetadata;
/**
* Created by xuc on 2018/1/7.
* 条件判断bean是否创建
*/
public class AppCondition implements Condition {
@Override
public boolean matches(ConditionContext conditionContext, AnnotatedTypeMetadata annotatedTypeMetadata) {
Environment environment = conditionContext.getEnvironment();
if (environment.acceptsProfiles("dev") || environment.acceptsProfiles("test")){
return true;
}
return false;
}
}
注：@profile注解value校验就是通过condition实现的，ProfileCondition为其实现类如下：
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE, ElementType.METHOD})
@Documented
@Conditional(ProfileCondition.class)
public @interface Profile {
/**
* The set of profiles for which the annotated component should be registered.
*/
String[] value();
}
class ProfileCondition implements Condition {
@Override
public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
if (context.getEnvironment() != null) {
MultiValueMap<String, Object> attrs = metadata.getAllAnnotationAttributes(Profile.class.getName());
if (attrs != null) {
for (Object value : attrs.get("value")) {
if (context.getEnvironment().acceptsProfiles(((String[]) value))) {
return true;
}
}
return false;
}
}
return true;
}
}
- bean注入歧义性问题
1.在待注入bean上加@Primary注解，声明该bean为优先注入
package com.springapp.mvc.application;
import com.springapp.mvc.easyBean.Braves;
import com.springapp.mvc.easyBean.IArms;
import com.springapp.mvc.easyBean.Machete;
import com.springapp.mvc.easyBean.Sword;
import org.springframework.context.annotation.*;
/**
* Created by xuc on 2018/1/7.
* 配置类
*/
@ComponentScan(basePackages = {"com.springapp.mvc"})
@Configuration
public class Application {
@Bean
@Conditional(AppCondition.class)
public Braves braves(IArms arms){
return new Braves(arms);
}
@Bean
@Profile("dev")
@Primary
public Sword sword() {
return new Sword();
}
@Bean
@Profile("test")
public Machete machete(){
return new Machete();
}
}
2.在被注入bean上加@Qualifier注解
package com.springapp.mvc.application;
import com.springapp.mvc.easyBean.Braves;
import com.springapp.mvc.easyBean.IArms;
import com.springapp.mvc.easyBean.Machete;
import com.springapp.mvc.easyBean.Sword;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.*;
/**
* Created by xuc on 2018/1/7.
* 配置类
*/
@ComponentScan(basePackages = {"com.springapp.mvc"})
@Configuration
public class Application {
@Bean
@Qualifier("sword")
public Braves braves(IArms arms){
return new Braves(arms);
}
@Bean
@Profile("dev")
public Sword sword() {
return new Sword();
}
@Bean
@Profile("test")
public Machete machete(){
return new Machete();
}
}
注：此处若存在多个（即多优先级），可自定义注解
- bean的作用域
| 作用域 | 描述 |
| singleton | 该作用域将 bean 的定义的限制在每一个 Spring IoC 容器中的一个单一实例(默认)。 |
| prototype | 该作用域将单一 bean 的定义限制在任意数量的对象实例。 |
| request | 该作用域将 bean 的定义限制为 HTTP 请求。只在 web-aware Spring ApplicationContext 的上下文中有效。 |
| session | 该作用域将 bean 的定义限制为 HTTP 会话。 只在web-aware Spring ApplicationContext的上下文中有效。 |
| global-session | 该作用域将 bean 的定义限制为全局 HTTP 会话。只在 web-aware Spring ApplicationContext 的上下文中有效。 |
package com.springapp.mvc.application;
import com.springapp.mvc.easyBean.Braves;
import com.springapp.mvc.easyBean.IArms;
import com.springapp.mvc.easyBean.Machete;
import com.springapp.mvc.easyBean.Sword;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.*;
import org.springframework.web.context.WebApplicationContext;
/**
* Created by xuc on 2018/1/7.
* 配置类
*/
@ComponentScan(basePackages = {"com.springapp.mvc"})
@Configuration
public class Application {
@Bean
public Braves braves(IArms arms){
return new Braves(arms);
}
@Bean
@Profile("dev")
@Scope(value = WebApplicationContext.SCOPE_GLOBAL_SESSION,
proxyMode = ScopedProxyMode.TARGET_CLASS)
public Sword sword() {
return new Sword();
}
@Bean
@Profile("test")
public Machete machete(){
return new Machete();
}
}
注：此处通过@Scope注解重新定义sword bean为会话级作用域，由于在使用braves时会优先加载sword，通过proxyMode声明代理该类，
即通过延迟注入的形式实现session级的sword注入到单例级的braves。如果该是接口的话：“proxyMode = ScopedProxyMode.INTERFACES”
环境： IDEA、Spring4.0
参考资料： 《spring实战》
