1.24 value注入简单数据

戴着假发的程序员出品

[查看视频教程]

我们在使用property和constructor-arg为bean注入属性时，如果属性是简单类型，我们可以通过value直接注入。

这里简单类型主要是指java的基本类型和String类型。

案例：

我们有一个Service类：

/**
 * @author 戴着假发的程序员
 *  
 * @description
 */
public class AccountService {
    private String appName;
    private int count;
    public void setAppName(String appName) {
        this.appName = appName;
    }
    public void setCount(int count) {
        this.count = count;
    }
    //无参数构造
    public AccountService(){}
     //有参数构造
    public AccountService(String appName,int count){
        this.appName = appName;
        this.count = count;
    }
    @Override
    public String toString(){
        return "appName:"+appName+";\r\ncount:"+count;
    }
}

AccountService有两个简单类型的属性，我们可以通过下面的方式注入属性：

<?xml version="1.0" encoding="UTF-8"?>
<beans  default-autowire="byName" 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">
    <!-- accountService 方式1 -->
    <bean id="accountService1" class="com.dk.demo1.service.AccountService">
        <property name="appName" value="假发"/>
        <property name="count" value="100"/>
    </bean>
    <!-- accountService 方式2 -->
    <bean id="accountService2" class="com.dk.demo1.service.AccountService">
        <property name="appName"><value>程序员</value></property>
        <property name="count"><value>1000000</value></property>
    </bean>
    <!-- accountService 方式3 -->
    <bean id="accountService3" class="com.dk.demo1.service.AccountService">
        <constructor-arg name="appName" value="戴假发"/>
        <constructor-arg name="count" value="999"/>
    </bean>
    <!-- accountService 方式4 -->
    <bean id="accountService4" class="com.dk.demo1.service.AccountService">
        <constructor-arg name="appName">
            <value>有假发</value>
        </constructor-arg>
        <constructor-arg name="count">
            <value>99</value>
        </constructor-arg>
    </bean>
</beans>

测试：

@Test
public void testValue(){
    ApplicationContext ac =
            new ClassPathXmlApplicationContext("applicationContext.xml");
    AccountService bean1 = (AccountService) ac.getBean("accountService1");
    AccountService bean2 = (AccountService) ac.getBean("accountService2");
    AccountService bean3 = (AccountService) ac.getBean("accountService3");
    AccountService bean4 = (AccountService) ac.getBean("accountService4");
    System.out.println(bean1);
    System.out.println(bean2);
    System.out.println(bean3);
    System.out.println(bean4);
}

结果:

appName:假发;
count:100
appName:程序员;
count:1000000
appName:戴假发;
count:999
appName:有假发;
count:99