Spring配置的三种主要装配机制

1.在XML中进行显示配置

package com.spring;
public class Address {
private String desc;
// getter setter
}

package com.spring;
public class Car {
private String desc;
}

package com.spring;

public class Student {
private String name;
private Address address;

public Student(Address address) {
this.address = address;
}
}

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"> 
<bean id="address" class="com.spring.Address" />
<bean id="car" class="com.spring.Car" />

<bean id="student" class="com.spring.Student">
<constructor-arg ref="address" /><!--构造函数注入 -->
<property name="car" ref="car" /><!-- set方法注入-->
</bean>
</beans>

2.在Java中进行显示配置

package com.spring;
public class Address {
private String desc;
// getter setter
}

package com.spring;

import org.springframework.stereotype.Component;
public class Car {
private String desc;
}

package com.spring;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@ComponentScan(basePackages = "com.spring")
public class JavaConfig {

@Bean
public Car car(){
return new Car();
}

@Bean
public Address address(){
return new Address();
}

@Bean
public Student student() {
Student student = new Student(address());
student.setCar(car());
return student;
}
}

3.隐式的bean发现机制和自动装配

package com.spring;

import org.springframework.stereotype.Component;

@Component("address")
public class Address {
private String desc;
// getter setter
}

package com.spring;

import org.springframework.stereotype.Component;

@Component("car")
public class Car {
private String desc;
}

package com.spring;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

@Component("student")
public class Student {
private String name;
private Address address;
private Car car;

@Autowired
public Student(Address address) {
this.address = address;
}

public Car getCar() {
return car;
}

@Autowired
public void setCar(Car car) {
this.car = car;
}
}

@Configuration
@ComponentScan(basePackages = "com.spring")
public class JavaConfig {}