Spring依赖注入——java项目中使用spring注解方式进行注入

标签：spring   依赖注入   java项目   

• Autowired是自动注入，自动从spring的上下文找到合适的bean来注入
• Resource用来指定名称注入
• Qualifier和Autowired配合使用，指定bean的名称
• Service，Controller，Repository分别标记类是Service层类，Controller层类，数据存储层的类，spring扫描注解配置时，会标记这些类要生成bean。
• Component是一种泛指，标记类是组件，spring扫描注解配置时，会标记这些类要生成bean。

上面的Autowired和Resource是用来修饰字段，构造函数，或者设置方法，并做注入的。而Service，Controller，Repository，Component则是用来修饰类，标记这些类要生成bean。

maven的pom.xml

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <org.springframework.version>3.1.1.RELEASE</org.springframework.version>
  </properties>
  
  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.8.1</version>
      <scope>test</scope>
    </dependency>
    
    <dependency>
	    <groupId>org.springframework</groupId>
	    <artifactId>spring-webmvc</artifactId>
	    <version>${org.springframework.version}</version>
	</dependency>
	<dependency>
	    <groupId>org.springframework</groupId>
	    <artifactId>spring-orm</artifactId>
	    <version>${org.springframework.version}</version>
	</dependency>
	<dependency>
	    <groupId>org.springframework</groupId>
	    <artifactId>spring-test</artifactId>
	    <version>${org.springframework.version}</version>
	    <type>jar</type>
	    <scope>test</scope>
	</dependency>
	<dependency>
	    <groupId>org.aspectj</groupId>
	    <artifactId>aspectjweaver</artifactId>
	    <version>1.8.2</version>
	</dependency>
	<dependency>
		<groupId>com.fasterxml.jackson.core</groupId>
		<artifactId>jackson-core</artifactId>
		<version>2.2.3</version>
	</dependency>
	<dependency>
		<groupId>com.fasterxml.jackson.core</groupId>
		<artifactId>jackson-databind</artifactId>
		<version>2.2.3</version>
	</dependency>
	<dependency>
		<groupId>com.fasterxml.jackson.core</groupId>
		<artifactId>jackson-annotations</artifactId>
		<version>2.2.3</version>
	</dependency>
  </dependencies>

1、建立dao层，给它添加@Repository注解(注：dao类不需实现某个接口，当然实现接口也可以)

package cn.outofmemory.helloannotation;

import org.springframework.stereotype.Repository;

@Repository
public class CarDao {

    public void insertCar(String car) {
        String insertMsg = String.format("inserting car %s", car);
        System.out.println(insertMsg);
    }

}

package cn.outofmemory.helloannotation;

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

@Service
public class CarService {

    @Autowired
    private CarDao carDao;

    public void addCar(String car) {
        this.carDao.insertCar(car);
    }
}

package cn.outofmemory.helloannotation;

import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;


public class App {
    public static void main( String[] args ){
        ApplicationContext appContext = new AnnotationConfigApplicationContext("cn.outofmemory.helloannotation");
        CarService service = appContext.getBean(CarService.class);
        service.addCar("宝马");
    }
}

4、applicationContext.xml配置文件(把该文件放到classpath下)

<?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-3.0.xsd
 http://www.springframework.org/schema/context
 http://www.springframework.org/schema/context/spring-context-3.0.xsd ">

    <!-- bean annotation driven -->
    <context:annotation-config />
    <context:component-scan base-package="cn.outofmemory.helloannotation" >
    </context:component-scan>
 </beans>

package cn.outofmemory.helloannotation;

import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;


public class App {
    public static void main( String[] args ) {
        //ApplicationContext appContext = new AnnotationConfigApplicationContext("cn.outofmemory.helloannotation");
<span style="white-space:pre">	String[] fileUrl = new String[]{"classpath*:applicationContext.xml"};   </span>
        ApplicationContext appContext = new ClassPathXmlApplicationContext(fileUrl）<span style="font-family: 'Comic Sans MS';">;</span>
        CarService service = appContext.getBean(CarService.class);
        service.addCar("宝马");
    }
}

CarService service = (CarService)appContext.getBean("carService");

参考：http://outofmemory.cn/code-snippet/3670/spring-inject-by-annotation

Spring依赖注入——java项目中使用spring注解方式进行注入

标签：spring   依赖注入   java项目   

原文地址：http://blog.csdn.net/liuxiao723846/article/details/47172015