public static void printAllFields(Class<?> clazz){Field[] fields=clazz.getDeclaredFields();System.out.println(Arrays.toString(fields));if(!clazz.getSuperclass().equals(Object.class)){printAllFields(clazz.getSuperclass());}}

public class UserController {private UserService userService;public UserService getUserService() {return userService;}public void setUserService(UserService userService) {this.userService = userService;}
}

 @Testpublic void testField() throws Exception {UserController userController=new UserController();Class<? extends UserController> clazz=userController.getClass();
//        Field[] declaredFields=clazz.getDeclaredFields();
//        Arrays.asList(declaredFields).stream().forEach(System.out::println);Field userServiceField=clazz.getDeclaredField("userService");UserService userService=new UserService();userServiceField.setAccessible(true);userServiceField.set(userController,userService);//获取get,set的名字String name=userServiceField.getName();name=name.substring(0,1).toUpperCase()+name.substring(1,name.length());String getMethodName="get"+name;String setMethodName="set"+name;Method method=clazz.getMethod(setMethodName,UserService.class);//在userController注入userService
        method.invoke(userController,userService);System.out.println(userController.getUserService());}

package littlepage.test;import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.FIELD})
public @interface Autowired {
}

package littlepage.test;import org.junit.Test;import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.stream.Stream;public class DemoTest {@Testpublic void testField() throws Exception {UserController userController=new UserController();Class<? extends UserController> clazz=userController.getClass();Stream.of(clazz.getDeclaredFields()).forEach(field->{String name=field.getName();Autowired annotation=field.getAnnotation(Autowired.class);if(annotation!=null){field.setAccessible(true);Class<?> type=field.getType();try {/*** 这个对象直接newInstance出来的* 在spring中这个bean是定义在注解或者xml中的，如何找到？*/Object object=type.getConstructor(null).newInstance();field.set(userController,object);} catch (InstantiationException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();} catch (InvocationTargetException e) {e.printStackTrace();} catch (NoSuchMethodException e) {e.printStackTrace();}}});}
}