Java 3.Spring的依赖注入

一、set方法注入

value ：值类型的注入

ref   ：对象类型的注入

pojo

public class Person {
	private String name;
	private Integer age;
	private Car car;
	public Person() {
		super();
		System.out.println("构造方法调用");
	}
	public void init() {
		System.out.println("Person被初始化了。。。");
	}
	public void destroy() {
		System.out.println("Person被摧毁了。。。");
	}

bean配置

        <bean name="car" class="com.Spring.pojo.Car">
        <property name="name" value="BWM"></property>
        <property name="color" value="red"></property>
        
        </bean>
        
        <bean name= "person1" class="com.Spring.pojo.Person">
        <property name="name" value="helen"></property>
        <property name="age" value="18"></property>
        <property name="car" ref="car"></property>
        </bean>

二、构造方法注入

1.创建Person的有参构造方法

	public Person(String name, Car car) {
		super();
		System.out.println("调用了构造方法Person(String name, Car car)");
		this.name = name;
		this.car = car;
	}

配置bean

        <bean name="person2" class="com.Spring.pojo.Person">
        <constructor-arg name="name" value="988" index="1" type="java.lang.Integer"></constructor-arg>
        <constructor-arg name="car" ref="car" index="0"></constructor-arg>
        </bean>

测试

	@Test
	@SuppressWarnings("resource")
	public void testConstructer() {  
		
		AbstractApplicationContext context = new ClassPathXmlApplicationContext("applicationContext-injection.xml");		
		Person person2=(Person) context.getBean("person2");
		System.out.println(person2);
	}

2.使用index指定参数的位置

pojo中有如下两个构造方法

	public Person(String name, Car car) {
		super();
		System.out.println("调用了构造方法Person(String name, Car car)");
		this.name = name;
		this.car = car;
	}
	
	public Person(Car car,Integer name) {
		super();
		System.out.println("调用了构造方法Person( Car car, int name)");
		this.name = name+"";
		this.car = car;
	}

配置bean

        <bean name="person2" class="com.Spring.pojo.Person">
        <constructor-arg name="name" value="988" index="1" type="java.lang.Integer"></constructor-arg>
        <constructor-arg name="car" ref="car" index="0"></constructor-arg>
        </bean>

3.使用type指定参数的类型

	public Person(String name, Car car) {
		super();
		System.out.println("调用了构造方法Person(String name, Car car)");
		this.name = name;
		this.car = car;
	}
	
	public Person(Car car,Integer name) {
		super();
		System.out.println("调用了构造方法Person( Car car, int name)");
		this.name = name+"";
		this.car = car;
	}

bean配置

        <bean name="person2" class="com.Spring.pojo.Person">
        <constructor-arg name="name" value="988" index="1" type="java.lang.Integer"></constructor-arg>
        <constructor-arg name="car" ref="car" index="0"></constructor-arg>
        </bean>

三、p名称空间注入

导入名称空间

典型案例：配置数据源

四、spl注入