SSM-Spring-07:Spring基于注解的di注入

------------吾亦无他,唯手熟尔,谦卑若愚,好学若饥-------------

注解:

  说起注解,哇哦,每个人都或多或少的用到过

  像什么@Overried,@Test,@Param等等之前就早已熟悉的注解,现在要用注解实现di的注入

  注解的本质是什么?就是一个接口,他里面的参数是什么呢?就是这个接口里面的方法,so,我们怎么做?

案例如下:

  基于注解的jar包就不用说了,按照之前的博客走下来的无需再添加新的jar包

  还是俩个类,一个car,一个student,学生有一辆小汽车,基于注解的di注入

    Car类

package cn.dawn.day07annotationdi;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component; /**
* Created by Dawn on 2018/3/5.
*/
@Component("car")
public class Car {
@Value("红色")
private String color;
@Value("奔驰")
private String type; public String getColor() {
return color;
} public void setColor(String color) {
this.color = color;
} public String getType() {
return type;
} public void setType(String type) {
this.type = type;
}
}

    @Componed("car")  //表示这个生成的对象的名字

    @Value("奔驰")    //用于给属性赋值

  Student类

package cn.dawn.day07annotationdi;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component; import javax.annotation.Resource; /**
* Created by Dawn on 2018/3/5.
*/
//student类
@Component("student")
public class Student {
@Value("老胡小子,呵呵哒")
private String name;
@Value("")
private Integer age; //@Resource(name = "car")
@Autowired
@Qualifier(value = "car")
private Car car; //带参构造
public Student(String name, Integer age, Car car) {
this.name = name;
this.age = age;
this.car = car;
} //无参构造
public Student() {
} public String getName() {
return name;
} public void setName(String name) {
this.name = name;
} public Integer getAge() {
return age;
} public void setAge(Integer age) {
this.age = age;
} public Car getCar() {
return car;
} public void setCar(Car car) {
this.car = car;
}
}

    一样的就不做解释了,说一下下面这几个

    @Resource(name="car")    //这个是javax包下的注解,可以实现域属性的注入,下面还有一种方式,

    @AutoWried

    @Qualifier(value="car")    //这两行联用,他是spring的注解,也是给对象的域属性赋值

  

  在Spring的配置文件中,需要配置一点内容,首先导入命名空间context,和注解的包扫描器(我是idea,写完下面的节点,上面的命名空间自动生成)

<?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:aop="http://www.springframework.org/schema/aop"
xmlns:p="http://www.springframework.org/schema/p" 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/aop
http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
<context:component-scan base-package="cn.dawn.day07annotationdi">
</context:component-scan> </beans>

  单测方法

package cn.dawn.day07annotationdi;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext; /**
* Created by Dawn on 2018/3/3.
*/
public class test20180306 { @Test
/*di注解注入*/
public void t01(){
ApplicationContext context=new ClassPathXmlApplicationContext("ApplicationContext-day07annotationdi.xml");
Student student = (Student) context.getBean("student");
System.out.println("学生"+student.getName()+"开"+student.getCar().getType());
}
}
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