6.Spring SpEL表达式

SpEL:spring表达式

　　格式：<property name="" value="#{表达式}">

1.#{123}，#{'jack'}:数字，字符串
2.#{beanId}:另一个bean引用
3.#{beanId.propName}:操作数据
4.#{beanId.toString()}:执行方法
5.#{T(类).字段|方法}：静态方法或字段


代码展示：
Customer.java

package com.gyf.model;

public class Customer {
    private String name;
    private String sex = "男";
    private double pi;
    private Address address;

    public String getName() {
        return name;
    }

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

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public double getPi() {
        return pi;
    }

    public void setPi(double pi) {
        this.pi = pi;
    }

    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "Customer{" +
                "name='" + name + '\'' +
                ", sex='" + sex + '\'' +
                ", pi=" + pi +
                ", address=" + address +
                '}';
    }
}

Address.java

package com.gyf.model;

public class Address {
    private String name;

    public String getName() {
        return name;
    }

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

    @Override
    public String toString() {
        return "Address{" +
                "name='" + name + '\'' +
                '}';
    }
}

beans.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">
    <!--spEL:spring表达式
        <property name="" value="#{表达式}">
        #{123}，#{'jack'}:数字，字符串
        #{beanId}:另一个bean引用
        #{beanId.propName}:操作数据
        #{beanId.toString()}:执行方法
        #{T(类).字段|方法}：静态方法或字段
    -->
    <bean name="address" class="com.gyf.model.Address">
        <property name="name" value="上海"></property>
    </bean>
    <bean id="customer" class="com.gyf.model.Customer">
        <!--#{beanId.xxx()}:执行方法-->
        <!--<property name="name" value="#{'alex'.toUpperCase()}"></property>-->
        <!--{T(类).字段|方法}：静态方法或字段-->
        <property name="pi" value="#{T(java.lang.Math).PI}"></property>
        <!--
        一个对象引用另一个对象的两种写法：
        1.ref:引用 <property name="address" ref="address"></property>
        2.SpEL:<property name="address" value="#{address}"></property>
        -->
        <property name="address" value="#{address}"></property>
        <!--{beanId.propName}:操作数据-->
        <property name="name" value="#{address.name}"></property>
    </bean>
</beans>

main.java

package com.gyf.test;

import com.gyf.model.Customer;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Run5 {
    @Test
    public void test() {
        ApplicationContext context = new ClassPathXmlApplicationContext("beans5.xml");
        Customer customer = (Customer) context.getBean("customer");
        System.out.println(customer);
    }
}