spring(學習記錄）泛型依賴注入

泛型依賴注入

spring 4.x以上版本才有

建立兩個帶泛型的類,并配置兩者的依賴關系，對于繼承這兩個類的子類,如果泛型相同,則會繼承這種依賴關系：

定義了兩個泛型base類:BaseService和BaseRepository

對于UserService和UserRpository分别繼承兩個base類,泛型都是User，則他們倆繼承了父類的依賴關系。

BaseRepository

package com.beans.generic.di;

public class BaseRepository<T> {
         
}      

BaseService

package com.beans.generic.di;

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

public class BaseService<T> {
  
     @Autowired
       protected BaseRepository<T> repository;
       
       public void add() {
         System.out.println("add....");
         System.out.println(repository);
       }
       
}      

UserRepository

package com.beans.generic.di;

import org.springframework.stereotype.Repository;

@Repository
public class UserRepository extends BaseRepository<User>{
        
}      

UserService

package com.beans.generic.di;

import org.springframework.stereotype.Service;

@Service
public class UserService extends BaseService<User>{
       
}      

配置檔案xml

<?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-4.0.xsd">

<context:component-scan base-package="com.beans.generic.di"></context:component-scan>

</beans>      

運作主類：

public static void main(String[] args) {
        ApplicationContext ctx = new ClassPathXmlApplicationContext("generic-di.xml");
        UserService userService = (UserService) ctx.getBean("userService");
        userService.add();
    }