Spring EL Lists,Maps实例 - Spring教程

在这篇文章中，我们将介绍如何使用Spring EL从 Map 和 List 中获得值。事实上，使用SpEL与 Map 和 List 的工作方式与Java是完全一样的。请参阅例如：

//get map whete key = 'MapA'
@Value("#{testBean.map['MapA']}")
private String mapA;

//get first value from list, list is 0-based.
@Value("#{testBean.list[0]}")
private String list;

Spring EL以注解的形式

在这里，创建了一个HashMap和ArrayList，并添加了一些初始测试数据。

package com.yiibai.core;

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

@Component("customerBean")
public class Customer {

    @Value("#{testBean.map['MapA']}")
    private String mapA;

    @Value("#{testBean.list[0]}")
    private String list;

    public String getMapA() {
        return mapA;
    }

    public void setMapA(String mapA) {
        this.mapA = mapA;
    }

    public String getList() {
        return list;
    }

    public void setList(String list) {
        this.list = list;
    }

    @Override
    public String toString() {
        return "Customer [mapA=" + mapA + ", list=" + list + "]";
    }

}

package com.yiibai.core;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.springframework.stereotype.Component;

@Component("testBean")
public class Test {

    private Map<String, String> map;
    private List<String> list;

    public Test() {
        map = new HashMap<String, String>();
        map.put("MapA", "This is MapA");
        map.put("MapB", "This is MapB");
        map.put("MapC", "This is MapC");

        list = new ArrayList<String>();
        list.add("List0");
        list.add("List1");
        list.add("List2");

    }

    public Map<String, String> getMap() {
        return map;
    }

    public void setMap(Map<String, String> map) {
        this.map = map;
    }

    public List<String> getList() {
        return list;
    }

    public void setList(List<String> list) {
        this.list = list;
    }

}

执行程序

Customer obj = (Customer) context.getBean("customerBean");
System.out.println(obj);

输出结果:

Customer [mapA=This is MapA, list=List0]

Spring EL以XML的形式

请参阅在XML文件定义bean的等效版本。

<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-3.0.xsd">

    <bean id="customerBean" class="com.yiibai.core.Customer">
        <property name="mapA" value="#{testBean.map['MapA']}" />
        <property name="list" value="#{testBean.list[0]}" />
    </bean>

    <bean id="testBean" class="com.yiibai.core.Test" />

</beans>

下载代码 – http://pan.baidu.com/s/1gdTxfKv