Spring 泛型依赖注入

Spring 泛型依赖注入，是利用泛型的优点对代码时行精简，将可重复使用的代码全部放到一个类之中，方便以后的维护和修改，同时在不增加代码的情况下增加代码的复用性。

示例代码：

1. 创建实体类
   Product

   
   package test.spring.model;public class Product {private int id ;private String name;/* setter getter省略 */@Overridepublic String toString() {return "Product [id=" + id + ", name=" + name + "]";}}

   User

   package test.spring.model;public class User {private int id;private String name;/* setter、getter省略 */@Overridepublic String toString() {return "User [id=" + id + ", name=" + name + "]";}public User() {super();}}

2. 创建Dao层相关接口及实现类
   
   对dao层的相同功能提取出来，创建一个带泛型的BaseDao类用于共用。

   package test.spring.Dao;import org.springframework.stereotype.Repository;/*必须加入注解，将BaseDao注入Spring容器，因为BaseService中有引用该类*/
   @Repository
   public class BaseDao<T> {public void add(T t) {System.out.println("BaseDao...."+t);}}

   
   UserDao接口

   package test.spring.Dao;import test.spring.model.User;public interface UserDao {public void add(User user);}
   

   UserDao实现类
    

   package test.spring.Dao;
   import org.springframework.stereotype.Repository;import test.spring.model.User;
   @Repository ("userDaoImpl")
   public class UserDaoImpl extends BaseDao<User> implements UserDao {}
   

   ProductDao接口
    

   package test.spring.Dao;import test.spring.model.Product;public interface ProductDao {public void add(Product pro);
   }

   ProductDao实现类
    

   package test.spring.Dao;import org.springframework.stereotype.Repository;import test.spring.model.Product;
   @Repository("productDao")
   public class ProductDaoImpl extends BaseDao<Product> implements ProductDao {}

3. Spring配置

   <?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.xsdhttp://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd"><context:component-scan base-package="test.spring" >	</context:component-scan></beans>

4. 测试

   package testSpring;import org.junit.Test;
   import org.springframework.context.ApplicationContext;
   import org.springframework.context.support.ClassPathXmlApplicationContext;import test.spring.model.Product;
   import test.spring.model.User;
   import test.spring.service.ProductService;
   import test.spring.service.UserService;public class TestSpring {@Testpublic void testUser() {ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");UserService userService=(UserService) ac.getBean("userService");userService.add(new User());System.out.println("-----------------------------");ProductService  proService= (ProductService) ac.getBean("prodcutService");proService.add(new Product());}
   }

   结果：