Spring4-EL从 Map 和 List 中获取元素

Posted 2020-09-06

1.创建Maven项目,项目名称springdemo47,如图所示

2.配置Maven,修改项目中的pom.xml文件,修改内容如下

<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>1.0.0</modelVersion>
  <groupId>shequ</groupId>
  <artifactId>springdemo13</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  
  <properties>
  	<java.version>1.7</java.version>
  	<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  	<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
  </properties>
  
  <repositories>
  	<repository>
  		<id>codelds</id>
  		<url>https://code.lds.org/nexus/content/groups/main-repo</url>
  	</repository>
  </repositories>
  
  <dependencies>
  	<dependency>
  		<groupId>javax.annotation</groupId>
  		<artifactId>jsr250-api</artifactId>
  		<version>1.0</version>
  	</dependency>
  	
  	<dependency>
  		<groupId>org.springframework</groupId>
  		<artifactId>spring-test</artifactId>
  		<version>4.1.4.RELEASE</version>
  	</dependency>
  	
  	<dependency>
  		<groupId>junit</groupId>
  		<artifactId>junit</artifactId>
  		<version>4.10</version>
  	</dependency>
  	
  	<dependency>
  		<groupId>org.springframework</groupId>
  		<artifactId>spring-core</artifactId>
  		<version>4.1.4.RELEASE</version>
  	</dependency>
  	
  	<dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>4.1.4.RELEASE</version>
    </dependency>
    
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-jdbc</artifactId>
        <version>4.1.4.RELEASE</version>
    </dependency>
    
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.34</version>
    </dependency>
       
  </dependencies>
  <build/>
</project>

3.在src/main/java下创建实体Bean Forum,包名(com.mycompany.shequ.bean)如图所示

4.实体Bean Forum的内容如下

package com.mycompany.shequ.bean;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component("forumBean")
public class Forum {
	private int fid;
	private String name;
	private String listName;
	public String getListName() {
		return listName;
	}
	@Value("#{forumPostBean.lists[0]}")
	public void setListName(String listName) {
		this.listName = listName;
	}
	public int getFid() {
		return fid;
	}
	public void setFid(int fid) {
		this.fid = fid;
	}
	public String getName() {
		return name;
	}
	@Value("#{forumPostBean.maps[‘map1‘]}")
	public void setName(String name) {
		this.name = name;
	}
}

5.在src/main/java下创建实体Bean ForumPost,包名(com.mycompany.shequ.bean)如图所示

6.实体Bean ForumPost的内容如下

package com.mycompany.shequ.bean;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.springframework.stereotype.Component;

@Component("forumPostBean")
public class ForumPost {
	private Map<String,String> maps;
	private List<String> lists;
	
	public ForumPost() {
		super();
		lists = new ArrayList<String>(0);
		lists.add("list1");
		lists.add("list2");
		
		maps = new HashMap<String, String>();
		maps.put("map1", "value1");
		maps.put("map2", "value2");
	}
	public Map<String, String> getMaps() {
		return maps;
	}
	public void setMaps(Map<String, String> maps) {
		this.maps = maps;
	}
	public List<String> getLists() {
		return lists;
	}
	public void setLists(List<String> lists) {
		this.lists = lists;
	}
}

7.在src/main/resource下创建核心的配置文件applicationContext.xml,如图所示

8.核心的配置文件applicationContext.xml的内容如下

<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:p="http://www.springframework.org/schema/p"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:util="http://www.springframework.org/schema/util"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
	http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
	http://www.springframework.org/schema/util
	http://www.springframework.org/schema/util/spring-util-4.0.xsd
	http://www.springframework.org/schema/context
	http://www.springframework.org/schema/context/spring-context-4.0.xsd">
	
	<context:component-scan base-package="com.mycompany.shequ.bean"/>

</beans>

9.在src/test/java下创建测试文件AppTest,包名(com.mycompany.shequ.test)如图所示

10.测试文件AppTest的内容如下

package com.mycompany.shequ.test;

import org.junit.Test;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.mycompany.shequ.bean.Forum;


public class AppTest {
	
	@Test
	public void beanTest(){
	    ConfigurableApplicationContext context = new 
	    ClassPathXmlApplicationContext("applicationContext.xml");
		Forum forum = (Forum) context.getBean("forumBean");
		System.out.println(forum.getName());
		System.out.println(forum.getListName());
		
	}
}	

11.在测试类AppTest的beanTest方法上右键运行,输出结果如图所示

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