Spring Bean注入

Spring Bean注入

Spring Bean注入

首先创建Bean类-People。

public class People {
	private int id;
	private String name;
	public People() {
		super();
		System.out.println("people 构造方法");
		// TODO Auto-generated constructor stub
	}
	public People(int id, String name) {
		super();
		this.id = id;
		this.name = name;
		System.out.println("people 有参构造方法");
	}
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	@Override
	public String toString() {
		return "People [id=" + id + ", name=" + name + "]";
	}
}

• Spring Bean注入方式有两种：

  • 通过构造方法设置值

  • 设置注入（通过set方法）

    如果属性是基本数据类型或String等。则设置如下：

    或者：

    <bean id="peo3" class="com.spring.People">
    		<property name="id">
    			<value>456value>
    		property>
    		<property name="name">
    			<value>youvalue>
    		property>
    bean>
    

    以上两种配置实现的效果都是一样的。

    测试代码如下：

    public class Test {
        public static void main(String [] args) {
            ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
  
            People people = ac.getBean("peo3",People.class);
  
            System.out.println(people);
        }
    }
  

  ​ 如果属性是set，则设置如下：

  <bean id="peo4" class="com.spring.People">
  		<property name="id">
  			<value>456value>
  		property>
  		<property name="name">
  			<value>youvalue>
  		property>
  		<property name="sets">
  			<set>
  				<value>1value>
  				<value>2value>
  				<value>3value>
  				<value>4value>
  			set>
  		property>
  bean>
  

  ​ 测试代码如下：

   public class Test {
        public static void main(String [] args) {
            ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
  
            People people = ac.getBean("peo4",People.class);
  
            System.out.println(people);
        }
    }
  

  如果属性是list的话。则设置如下：

  <bean id="peo4" class="com.spring.People">
  		<property name="id">
  			<value>456value>
  		property>
  		<property name="name">
  			<value>youvalue>
  		property>
  		<property name="sets">
  			<set>
  				<value>1value>
  				<value>2value>
  				<value>3value>
  				<value>4value>
  			set>
  		property>
  		<property name="lists">
  			<list>
  				<value>list1value>
  				<value>list2value>
  				<value>list3value>
  			list>
  		property>
  	bean>
  

  如果list只有一个值，可以用以下配置：

  <property name="lists" value="list123">property>
  

  测试代码如下：

   public class Test {
        public static void main(String [] args) {
            ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
  
            People people = ac.getBean("peo4",People.class);
  
            System.out.println(people);
        }
    }
  
  

  如果属性是数组的话。则设置如下：

  <bean id="peo4" class="com.spring.People">
  		<property name="id">
  			<value>456value>
  		property>
  		<property name="name">
  			<value>youvalue>
  		property>
  		<property name="sets">
  			<set>
  				<value>1value>
  				<value>2value>
  				<value>3value>
  				<value>4value>
  			set>
  		property>
  		<property name="lists">
  			<list>
  				<value>list1value>
  				<value>list2value>
  				<value>list3value>
  			list>
  		property>
  		
  		<property name="strs">
  			<array>
  				<value>array1value>
  				<value>array2value>
  				<value>array3value>
  			array>
  		property>
  bean>
  
  

  如果数组中只有一个值，可以用以下配置：

  <property name="strs" value="array1">property>
  
  

  如果属性是map的话。则设置如下：

  <bean id="peo4" class="com.spring.People">
  		<property name="id">
  			<value>456value>
  		property>
  		<property name="name">
  			<value>youvalue>
  		property>
  		<property name="map">
  			<map>
  				<entry key="1" value="map1">
  				entry>
  				<entry key="2" value="map2">
  				entry>
  			map>
  		property>
  bean>
  
  

  测试代码同上。

​ 如果属性是Properties的话。则设置如下:

<property name="demo">
			<props>
				<prop key="prop1">prop1prop>
				<prop key="prop2">prop2prop>
			props>
property>