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Spring学习四----------Bean的配置之Bean的配置项及作用域
Bean的作用域（每个作用域都是在同一个Bean容器中）
1.singleton：单例，指一个Bean容器中只存在一份（默认）
2.prototype：每次请求（每次使用）创建新的实例，destory方式不生效
3.request：每次http请求创建一个实例且仅在当前request内生效（只能在web中使用）
4.session：同上，每次http请求创建一个实例，当前session内有效（只能在web中使用）
5.global session：基于portlet的web中有效（portlet定义了global session），如果是在单个web中，同session。（只能在web中使用）
实例
1.singleton和prototype
1.1 目录结构
1.2 pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>org.spring</groupId>
<artifactId>Spring</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>Spring</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<spring.version>4.3.7.RELEASE</spring.version>
</properties>
<dependencies>
<!-- junit依赖 -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<!-- spring依赖 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-beans</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${spring.version}</version>
</dependency>
</dependencies>
</project>
1.3 spring-beanscope.xml（scope="singleton" || scope="prototype"）
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="beanScope" class="org.spring.bean.BeanScope" scope="singleton"/>
</beans>
1.4 BeanScope.java
package org.spring.bean;
public class BeanScope {
public void say () {
System.out.println("hashCode:" + this.hashCode());//通过hashCode判断是否是同一个实例
}
}
1.5 UnitTestBase.java
package org.spring.ioc.test;
import org.junit.After;
import org.junit.Before;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.util.StringUtils;
/**
* 单元测试初始化类
*
*/
public class UnitTestBase {
private ClassPathXmlApplicationContext context;
private String springXmlPath;
/**
* 无参构造器
*/
public UnitTestBase() {
}
/**
* 含参构造器
*
* @param springXmlPath
* spring配置文件路径
*/
public UnitTestBase(String springXmlPath) {
this.springXmlPath = springXmlPath;
}
/**
* 初始化spring配置文件
*/
@Before//在@Test注解的方法执行前执行
public void before() {
if(StringUtils.isEmpty(springXmlPath)) {//默认spring配置文件路径
springXmlPath = "classpath*:spring-*.xml";
}
//加载配置文件，一个context表示一个容器
context = new ClassPathXmlApplicationContext(springXmlPath.split("[,\\s]+"));
//启动组件
context.start();
}
/**
* 销毁spring组件
*/
@After//在@Test注解的方法执行后执行
public void after() {
context.destroy();//销毁组件
}
/**
* 获取spring中定义的bean实例
*
* @param beanId
*
* @return
*/
@SuppressWarnings("unchecked")
protected <T extends Object> T getBean(String beanId) {
return (T) context.getBean(beanId);
}
/**
* 获取spring中定义的bean实例
*
* @param clazz
*
* @return
*/
protected <T extends Object> T getBean(Class<T> clazz) {
return (T) context.getBean(clazz);
}
}
1.6 TestBeanScope.java
package org.spring.ioc.test;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.BlockJUnit4ClassRunner;
import org.spring.bean.BeanScope;
@RunWith(BlockJUnit4ClassRunner.class)//指定JUnit默认执行类
public class TestBeanScope extends UnitTestBase {
public TestBeanScope() {//通过构造方法传入spring配置文件路径
super("classpath*:spring-beanScope.xml");
}
@Test
public void testScope() {
BeanScope beanScope = super.getBean("beanScope");
beanScope.say();
/**
* 若在两个方法中执行这两行代码，则hashCode会不同。
* 因为每个test方法执行前都会执行@Before,会重新加载spring配置文件，此时是在两个容器中，所以不同
*/
BeanScope beanScope2 = super.getBean("beanScope");
beanScope2.say();
}
}
1.7 singleton效果预览
1.8 prototype效果预览
2.request和session
2.1 项目结构
2.2 pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>org.spring</groupId>
<artifactId>springBeanScope</artifactId>
<packaging>war</packaging>
<version>0.0.1-SNAPSHOT</version>
<name>springBeanScope Maven Webapp</name>
<url>http://maven.apache.org</url>
<properties>
<spring.version>4.3.7.RELEASE</spring.version>
</properties>
<dependencies>
<!-- junit依赖 -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<!-- spring核心依赖 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>${spring.version}</version>
</dependency>
<!-- spring web层依赖 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${spring.version}</version>
</dependency>
<!-- jstl -->
<dependency>
<groupId>jstl</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<!-- servlet -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
</dependency>
</dependencies>
<build>
<finalName>springBeanScope</finalName>
</build>
</project>
2.3 mvc-dispatcher-servlet.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"
xmlns:mvc="http://www.springframework.org/schema/mvc"
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
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc.xsd">
<!-- 开启包扫描 -->
<context:component-scan base-package="org.spring.*"/>
<!-- 开启注解 -->
<mvc:annotation-driven/>
<!-- 定义视图解析器 -->
<bean id="viewResolver"
class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="http://www.mamicode.com/WEB-INF/jsp/"/>
<property name="suffix" value="http://www.mamicode.com/.jsp"/>
</bean>
</beans>
2.4 BeanScope.xml
package org.spring.bean;
public class BeanScope {
public int say () {
return this.hashCode();//通过返回的hashCode判断是否是同一个实例
}
}
2.5 spring.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"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="beanScope" class="org.spring.bean.BeanScope" scope="singleton"/>
</beans>
2.6 web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
version="3.0" metadata-complete="true">
<!-- 启动spring的监听器，默认加载applicationContext.xml -->
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<!-- 自定义spring配置文件路径 -->
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:spring.xml</param-value>
</context-param>
<!-- 拦截所有请求，交由springMVC处理 -->
<servlet>
<servlet-name>springMVC</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:mvc-dispatcher-servlet.xml</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>springMVC</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
2.7 BeanScopeAction.java
package org.spring.action;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.http.HttpSession;
import org.spring.bean.BeanScope;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
@Controller
public class BeanScopeAction implements ApplicationContextAware {
private ApplicationContext context;
@RequestMapping("/")
public String testScope(ModelMap map, HttpSession session) {
BeanScope scope = (BeanScope) context.getBean("beanScope");
List<Integer> list = new ArrayList<Integer>();
for(int i = 0; i < 3; i++){
list.add(scope.say());
}
map.addAttribute("list", list);
map.addAttribute("session", session);
return "scope";
}
public void setApplicationContext(ApplicationContext context) throws BeansException {
this.context = context;
}
}
2.8 scope.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Spring作用域测试</title>
</head>
<body>
<font color="red">Session:${session }</font><br/>
<c:forEach var="hashCode" items="${list }" varStatus="status">
第${status.index + 1 }次获取实例：${hashCode }<br/>
</c:forEach>
</body>
</html>
2.9 效果预览
需刷新才能看见效果，截图表达不清晰，可复制代码自行运行刷新查看结果。
3.global session
需多个项目才能看见结果，此处不做测试。
参考：http://www.imooc.com/video/3750/
Spring学习四----------Bean的配置之Bean的配置项及作用域
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