Spring使用注解代替XML配置

1.导入命名空间

XML Catalog中除了要导入spring-beans以外，还要导入spring-context。

2.在applicationContext.xml文件中，添加

<context:component-scan base-package="Object"></context:component-scan>

其中，base-package中表示要扫描的包名。我这里表示扫描Object包及其子包下所有的注解。

3.为要创建Bean对象的JAVABean对象添加注解：

@Component("user") //user为Bean的name//以下三个注解作用和Component完全相同，只是为了在MVC中方便查看@Service("user")//service层@Controller("user")//web层@Repository("user")//dao层

4.设置Bean对象的作用范围

@Scope(scopeName="singleton") //单例@Scope(scopeName="prototype") //多例

5.属性注入

在要注入属性的Set方法上添加注解：

//值类型@Value(value="wxs") //wxs为属性值//对象类型@Resource(name="car") //car为Car类的Bean对象

6.生命周期

@PostConstruct//在对象被创建后调用@PreDestroy//在对象被销毁前掉调用

Demo:

<!--src/applicationContext.xml --><?xml version="1.0" encoding="UTF-8"?><beans     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"     xmlns="http://www.springframework.org/schema/beans"     xmlns:context="http://www.springframework.org/schema/context"     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.2.xsd ">    <context:component-scan base-package="Object"></context:component-scan></beans>

//Object.User.java:package Object;import javax.annotation.PostConstruct;import javax.annotation.PreDestroy;import javax.annotation.Resource;import org.springframework.beans.factory.annotation.Value;import org.springframework.context.annotation.Scope;import org.springframework.stereotype.Component;@Component("user")@Scope(scopeName="singleton")public class User {    private String name;    private Integer age;    private Car car;    public Car getCar() {        return car;    }    @Resource(name="car")    public void setCar(Car car) {        this.car = car;    }    public String getName() {        return name;    }    @Value("wxs")    public void setName(String name) {        this.name = name;    }    public Integer getAge() {        return age;    }    @Value("18")    public void setAge(Integer age) {        this.age = age;    }    @Override    public String toString() {        return "User [name=" + name + ", age=" + age + ", car=" + car + "]";    }    @PostConstruct    public void init(){        System.out.println("init...");    }    @PreDestroy    public void destory() {        System.out.println("destory...");    }}

//Object.Car.java:package Object;import org.springframework.beans.factory.annotation.Value;import org.springframework.stereotype.Component;@Component("car")public class Car {    private String name;    private String color;    public String getName() {        return name;    }    @Value("兰博基尼")    public void setName(String name) {        this.name = name;    }    public String getColor() {        return color;    }    @Value("绿色")    public void setColor(String color) {        this.color = color;    }    @Override    public String toString() {        return "Car [name=" + name + ", color=" + color + "]";    }}

//Demo.UserTest.java:package Demo;import org.junit.Test;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;import Object.User;public class UserTest {    @Test    public void f1(){        //这里只是为了能够调用ac.close()方法，才使用ClassPathXmlApplicationContext。正常应使用ApplicationContext        ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");        User u = (User)ac.getBean("user");        System.out.println(u);        ac.close();    }}

运行结果：

init...User [name=wxs, age=18, car=Car [name=兰博基尼, color=绿色]]destory...