spring学习八：spring表达式

JSP页面使用过EL表达式：${}

Spring有Spring表达式：#{}

Spring表达式用于获取bean的属性值

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns="http://www.springframework.org/schema/beans"
       xmlns:util="http://www.springframework.org/schema/util"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
                            http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.3.xsd">


    <util:list id="interestBean">
        <value>钓鱼</value>
        <value>国画</value>
        <value>做饭</value>
    </util:list>
    <util:set id="cityBean">
        <value>金陵</value>
        <value>洛阳</value>
        <value>北平</value>
    </util:set>
    <util:map id="scoreBean">
        <entry key="english" value="90"/>
        <entry key="math" value="80"/>
    </util:map>
    <util:properties id="dbBean">
        <prop key="username">sally</prop>
        <prop key="password">1234</prop>
    </util:properties>
    <bean id="user" class="org.spring.teach.User">
        <property name="name" value="#{interestBean[0]}"/>
        <property name="city" value="#{cityBean[0]}"/>
        <!--
        可以使用[]来访问属性，这种方式支持中文
        <property name="score" value="#{scoreBean['english']}"/>-->
        <property name="score" value="#{scoreBean.english}"/>
        <property name="username" value="#{dbBean.username}"/>
    </bean>
</beans>

public class User {

    private String name;
    private String city;
    private String score;
    private String username;

    public void setName(String name) {
        this.name = name;
    }

    public void setCity(String city) {
        this.city = city;
    }

    public void setScore(String score) {
        this.score = score;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    @Override
    public String toString() {
        return "User{" +
                "name='" + name + '\'' +
                ", city='" + city + '\'' +
                ", score='" + score + '\'' +
                ", username='" + username + '\'' +
                '}';
    }
}

public class TestCase {

    private AbstractApplicationContext app;

    @Before
    public void before() {
        app = new ClassPathXmlApplicationContext("classpath:spring.xml");
    }

    @After
    public void after() {
        app.close();
    }

    @Test
    public void test() {
        User user = app.getBean("user", User.class);
        System.out.println(user);
    }
}

一月 25, 2019 12:02:16 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@7c53a9eb: startup date [Fri Jan 25 12:02:16 CST 2019]; root of context hierarchy
一月 25, 2019 12:02:16 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [spring.xml]
一月 25, 2019 12:02:17 下午 org.springframework.context.support.ClassPathXmlApplicationContext doClose
信息: Closing org.springframework.context.support.ClassPathXmlApplicationContext@7c53a9eb: startup date [Fri Jan 25 12:02:16 CST 2019]; root of context hierarchy
User{name='钓鱼', city='金陵', score='90', username='sally'}

Process finished with exit code 0