Spring 4.x可以支持泛型依賴注入，也就是子類可以繼承父類的依賴，注入相應的泛型成員變量子類。
比如，有泛型基類 BaseService<T>和BaseController<T>，Controller包含Service成員，分別有Teacher和Student兩個子類，TeacherService和StudentService、TeacherController和StudentController。
1、 BaseService<T>
package com.generic.di;
public class BaseService<T> {
}
2、 BaseController<T>
package com.generic.di;
import org.springframework.beans.factory.annotation.Autowired;
public class BaseController<T> {
@Autowired
protected BaseService<T> service;
public void execute() {
System.out.println("execute...");
System.out.println(service); // 此處打印出實際的子類對象
}
}
3、TeacherService
package com.generic.di.teacher;
import org.springframework.stereotype.Service;
import com.generic.di.BaseService;
@Service
public class TeacherService extends BaseService<Teacher> {
}
4、TeacherController
package com.generic.di.teacher;
import org.springframework.stereotype.Controller;
import com.generic.di.BaseController;
@Controller
public class TeacherController extends BaseController<Teacher> {
}
5、StudentService
package com.generic.di.student;
import org.springframework.stereotype.Service;
import com.generic.di.BaseService;
@Service
public class StudentService extends BaseService<Student> {
}
6、StudentController
package com.generic.di.student;
import org.springframework.stereotype.Controller;
import com.generic.di.BaseController;
@Controller
public class StudentController extends BaseController<Student> {
}
7、配置文件
<?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-3.2.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd">
<context:component-scan
base-package="com.generic">
</context:component-scan>
</beans>
8、main
public class Main {
public static void main(String[] args) {
ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("ApplicationContext.xml");
StudentController studentController = (StudentController) context.getBean("studentController");
studentController.execute();
TeacherController teacherController = (TeacherController) context.getBean("teacherController");
teacherController.execute();
}
}
執行結果
execute...
com.generic.di.student.StudentService@d6da883
execute...
com.generic.di.teacher.TeacherService@45afc369
從結果可以看出，StudentController注入的是StudentSerive對象，TeacherController注入的是TeacherService對象，說明泛型基類的依賴關係，被子類自動繼承，並根據泛型找到對應的子類。
