Spring配置介绍

首先说说别名alias，以一个代码的例子讲解

首先是一个User实体类

package com.zhiying.pojo;

public class User {
    private String name;

    public String getName() {
        return name;
    }

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

    public void show() {
        System.out.println("name=" + name);
    }
}
      

然后是配置文件

<?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
        https://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="user" class="com.zhiying.pojo.User">
        <property name="name" value="贺志营"/>
    </bean>

<!--    添加了别名我们可以通过别名来获取-->
    <alias name="user" alias="me"/>


</beans>      

最后是通过别名测试

import com.zhiying.pojo.User;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MyTest {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
        User user = (User) context.getBean("me");
        user.show();
    }
}
      

运行结果：

可以获取

bean的配置

把上面的配置文件修改为如下

<?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
        https://www.springframework.org/schema/beans/spring-beans.xsd">

<!--
    bean的配置
    id：bean的唯一标识符，也就是我们的对象名
    class：bean对象对应的全限类名，包名+类名
    name：也是别名
-->
    <bean id="user" class="com.zhiying.pojo.User" name="hehe">
        <property name="name" value="贺志营"/>
    </bean>


</beans>      

把测试类也修改了

import com.zhiying.pojo.User;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MyTest {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
        User user = (User) context.getBean("hehe");
        user.show();
    }
}
      

这里的name属性值可以有多个，把配置文件修改为下

<?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
        https://www.springframework.org/schema/beans/spring-beans.xsd">

<!--
    bean的配置
    id：bean的唯一标识符，也就是我们的对象名
    class：bean对象对应的全限类名，包名+类名
    name：也是别名，可以同时取多个
-->
    <bean id="user" class="com.zhiying.pojo.User" name="hehe me,you;aa">
        <property name="name" value="贺志营"/>
    </bean>


</beans>      

测试类也修改了

import com.zhiying.pojo.User;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MyTest {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
        User user = (User) context.getBean("hehe");
        User user1 = (User) context.getBean("me");
        User user2 = (User) context.getBean("aa");
        user.show();
        user1.show();
        user2.show();
    }
}
      

这里的name别名，比上面那个alias强大。

import：可以将多个配置文件导入合并为一个，修改配置文件如下

<?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
        https://www.springframework.org/schema/beans/spring-beans.xsd">

<!--
    bean的配置
    id：bean的唯一标识符，也就是我们的对象名
    class：bean对象对应的全限类名，包名+类名
    name：也是别名
-->
    <bean id="user" class="com.zhiying.pojo.User" name="hehe me,you">
        <property name="name" value="贺志营"/>
    </bean>


</beans>      

<?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
        https://www.springframework.org/schema/beans/spring-beans.xsd">
    <bean id="user" class="com.zhiying.pojo.User" name="aa">
        <property name="name" value="贺志营"/>
    </bean>
</beans>      

<?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
        https://www.springframework.org/schema/beans/spring-beans.xsd">

    <import resource="Beans.xml"/>
    <import resource="beans1.xml"/>
</beans>      

import com.zhiying.pojo.User;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MyTest {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        User user = (User) context.getBean("hehe");
        User user1 = (User) context.getBean("me");
        User user2 = (User) context.getBean("aa");
        user.show();
        user1.show();
        user2.show();
    }
}