springboot高级功能（三）自定义注解实现方式全解析

1.     用于描述类、接口(包括注解类型) 或enum声明 Class, interface (including annotation type), or enum declaration 
2.     TYPE,
3. 
4.     用于描述域 Field declaration (includes enum constants)
5.     FIELD,
6. 
7.     用于描述方法 Method declaration
8. METHOD,
9. 
10.     用于描述参数 Formal parameter declaration 
11. PARAMETER,
12. 
13.     用于描述构造器 Constructor declaration
14.     CONSTRUCTOR,
15. 
16.     用于描述局部变量 Local variable declaration
17.     LOCAL_VARIABLE,
18. 
19.     Annotation type declaration
20.     ANNOTATION_TYPE,
21. 
22.     用于描述包 Package declaration
23.     PACKAGE,
24. 
25.     用来标注类型参数 Type parameter declaration
26.     TYPE_PARAMETER,
27. 
28. *能标注任何类型名称 Use of a type
29.     TYPE_USE

1. package com.airboot.bootdemo.config;
2. import org.springframework.context.annotation.Conditional;
3. import java.lang.annotation.*;
4. 
5. @Retention(RetentionPolicy.RUNTIME)
6. @Target({ElementType.TYPE, ElementType.METHOD})
7. @Documented
8. @Conditional(CustomPropertyCondition.class)
9. public @interface CustomProperty {
10. 
11. //参数
12.     String name() default "";
13. /**
14.          * havingValue数组，支持or匹配
15.          */
16. 
17. //参数
18.     String[] havingValue() default {};
19. 
20. }

1. public class CustomPropertyCondition implements Condition {
2. @Override
3. public boolean matches(ConditionContext conditionContext, AnnotatedTypeMetadata annotatedTypeMetadata) {
4. return false;
5.     }
6. }

1. 
2. import org.springframework.context.annotation.Condition;
3. import org.springframework.context.annotation.ConditionContext;
4. import org.springframework.core.type.AnnotatedTypeMetadata;
5. import org.springframework.web.bind.annotation.RequestMapping;
6. 
7. import java.util.Map;
8. 
9. 
10. public class CustomPropertyCondition implements Condition {
11. @Override
12. public boolean matches(ConditionContext conditionContext, AnnotatedTypeMetadata annotatedTypeMetadata) {
13. //获取注解上的参数和配置值
14. Map<String, Object> annotationAttributes = annotatedTypeMetadata.getAnnotationAttributes(RequestMapping.class.getName());
15. //获取具体的参数值
16. String propertyName = (String) annotationAttributes.get("name");
17. String[] values = (String[]) annotationAttributes.get("havingValue");
18. if (0 == values.length) {
19. return false;
20.         }
21. //从application.properties中获取配置
22. String propertyValue = conditionContext.getEnvironment().getProperty(propertyName);
23. // 有一个匹配上就ok
24. for (String havingValue : values) {
25. if (propertyValue.equalsIgnoreCase(havingValue)) {
26. return true;
27.             }
28.         }
29. return false;
30.     }
31. }

1. @RequestMapping(value ="/Demo")
2. @Controller
3. @ResponseBody
4. @Api("demo测试类")
5. @CustomProperty(name = "condition",havingValue = {"2"})
6. public class DemoController {
7. 
8. 
9. }

1. package com.airboot.bootdemo.config;
2. 
3. import java.lang.annotation.*;
4. 
5. 
6. @Target({ElementType.PARAMETER, ElementType.METHOD})
7. @Retention(RetentionPolicy.RUNTIME)
8. @Documented
9. public @interface UserCheck {
10. 
11. //当前用户在request中的名字
12.     String value() default "userid";
13. }

1. package com.airboot.bootdemo.config;
2. 
3. import org.springframework.core.MethodParameter;
4. import org.springframework.web.bind.support.WebDataBinderFactory;
5. import org.springframework.web.context.request.NativeWebRequest;
6. import org.springframework.web.method.support.HandlerMethodArgumentResolver;
7. import org.springframework.web.method.support.ModelAndViewContainer;
8. 
9. public class UserCheckMethodArgumentResolver implements HandlerMethodArgumentResolver {
10. @Override
11. public boolean supportsParameter(MethodParameter methodParameter) {
12. return false;
13.     }
14. 
15. @Override
16. public Object resolveArgument(MethodParameter methodParameter, ModelAndViewContainer modelAndViewContainer, NativeWebRequest nativeWebRequest, WebDataBinderFactory webDataBinderFactory) throws Exception {
17. return null;
18.     }
19. }

1. import com.airboot.bootdemo.entity.DemoVO;
2. import org.springframework.core.MethodParameter;
3. import org.springframework.web.bind.support.WebDataBinderFactory;
4. import org.springframework.web.context.request.NativeWebRequest;
5. import org.springframework.web.method.support.HandlerMethodArgumentResolver;
6. import org.springframework.web.method.support.ModelAndViewContainer;
7. 
8. public class UserCheckMethodArgumentResolver implements HandlerMethodArgumentResolver {
9. @Override
10. public boolean supportsParameter(MethodParameter parameter) {
11. if (parameter.getParameterType().isAssignableFrom(DemoVO.class) && parameter.hasParameterAnnotation(UserCheck.class)) {
12. return true;
13.         }
14. return false;
15.     }
16. 
17. @Override
18. public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer, NativeWebRequest webRequest, WebDataBinderFactory binderFactory) throws Exception {
19. UserCheck currentUserAnnotation = parameter.getParameterAnnotation(UserCheck.class);
20. //获取head中的
21. String userId = webRequest.getHeader("userId");
22. //组装入参 return后的参数 类型需要和controllor中的相同 
23. DemoVO demoVO = new DemoVO();
24.         demoVO.setId(Long.valueOf(1));
25. return demoVO;
26.     }
27. }

1. @RequestMapping(value = "/selectDemoByVo")
2. public List<DemoVO> selectDemoByVo(@RequestBody @UserCheck DemoVO demoVO) {
3. return demoService.selectDemoVO(demoVO);
4.     }

1. 
2. 1.JoinPoint  
3. * java.lang.Object[] getArgs()：获取连接点方法运行时的入参列表； 
4. * Signature getSignature() ：获取连接点的方法签名对象； 
5. * java.lang.Object getTarget() ：获取连接点所在的目标对象； 
6. * java.lang.Object getThis() ：获取代理对象本身； 
7. 
8. 2.ProceedingJoinPoint  
9. * ProceedingJoinPoint继承JoinPoint子接口，它新增了两个用于执行连接点方法的方法： 
10. * java.lang.Object proceed() throws java.lang.Throwable：通过反射执行目标对象的连接点处的方法； 
11. * java.lang.Object proceed(java.lang.Object[] args) throws java.lang.Throwable：通过反射执行目标对象连接点处的方法，不过使用新的入参替换原来的入参。

1. import java.lang.annotation.ElementType;
2. import java.lang.annotation.Retention;
3. import java.lang.annotation.RetentionPolicy;
4. import java.lang.annotation.Target;
5. 
6. @Target({ ElementType.METHOD })
7. @Retention(RetentionPolicy.RUNTIME)
8. public @interface TestAnnotation {
9. 
10. int p0() default 0;
11.     String p1() default "";
12.     Class<?> clazz();
13. 
14. }

1. import org.aspectj.lang.ProceedingJoinPoint;
2. import org.aspectj.lang.annotation.*;
3. import org.springframework.stereotype.Component;
4. import lombok.extern.slf4j.Slf4j;
5. 
6. @Slf4j
7. @Aspect
8. @Component
9. public class TestAspect {
10. 
11. // 切入点签名
12. @Pointcut("@annotation(com.airboot.bootdemo.config.TestAnnotation)")
13. private void cut() {
14.     }
15. 
16. // 前置通知
17. @Before("cut()")
18. public void BeforeCall() {
19.         log.info("====前置通知start");
20. 
21.         log.info("====前置通知end");
22.     }
23. 
24. // 环绕通知
25. @Around(value = "cut()")
26. public Object AroundCall(ProceedingJoinPoint joinPoint) throws Throwable {
27.         log.info("====环绕通知start");
28. 
29. // 注解所切的方法所在类的全类名
30. String typeName = joinPoint.getTarget().getClass().getName();
31.         log.info("目标对象:[{}]", typeName);
32. 
33. // 注解所切的方法名
34. String methodName = joinPoint.getSignature().getName();
35.         log.info("所切方法名:[{}]", methodName);
36. 
37. StringBuilder sb = new StringBuilder();
38. // 获取参数
39.         Object[] arguments = joinPoint.getArgs();
40. for (Object argument : arguments) {
41.             sb.append(argument.toString());
42.         }
43.         log.info("所切方法入参：[{}]", sb.toString());
44. 
45. // 统计方法执行时间
46. long start = System.currentTimeMillis();
47. 
48. //执行目标方法，并获得对应方法的返回值
49. Object result = joinPoint.proceed();
50.         log.info("返回结果:[{}]", result);
51. 
52. long end = System.currentTimeMillis();
53.         log.info("====执行方法共用时：[{}]", (end - start));
54. 
55.         log.info("====环绕通知之结束");
56. return result;
57.     }
58. 
59. // 后置通知
60. @After("cut()")
61. public void AfterCall() {
62.         log.info("====后置通知start");
63. 
64.         log.info("====后置通知end");
65.     }
66. 
67. // 最终通知
68. @AfterReturning("cut()")
69. public void AfterReturningCall() {
70.         log.info("====最终通知start");
71. 
72.         log.info("====最终通知end");
73.     }
74. 
75. // 异常通知
76. @AfterThrowing(value = "cut()", throwing = "ex")
77. public void afterThrowing(Throwable ex) {
78. throw new RuntimeException(ex);
79.     }
80. 
81. }

1. @RequestMapping(value = "/selectDemoByVo")
2. @TestAnnotation(p0 = 123, p1 = "qaws",clazz = DemoVO.class)
3. public List<DemoVO> selectDemoByVo(@RequestBody DemoVO demoVO) {
4. return demoService.selectDemoVO(demoVO);
5.     }

1. import java.lang.annotation.*;
2. 
3. @Target(ElementType.METHOD)
4. @Retention(RetentionPolicy.RUNTIME)
5. @Documented
6. public @interface InterceptorAnnotation {
7. 
8. 
9.     String[] value() default {};
10. 
11.     String[] authorities() default {};
12. 
13.     String[] roles() default {};
14. }

1. import org.springframework.web.method.HandlerMethod;
2. import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
3. 
4. import javax.servlet.http.HttpServletRequest;
5. import javax.servlet.http.HttpServletResponse;
6. import java.lang.reflect.Method;
7. 
8. public class TestAnnotationInterceptor extends HandlerInterceptorAdapter {
9. // 在调用方法之前执行拦截
10. @Override
11.     public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
12. // 将handler强转为HandlerMethod, 前面已经证实这个handler就是HandlerMethod
13. HandlerMethod handlerMethod = (HandlerMethod) handler;
14. // 从方法处理器中获取出要调用的方法
15. Method method = handlerMethod.getMethod();
16. // 获取出方法上的自定义注解
17. InterceptorAnnotation access = method.getAnnotation(InterceptorAnnotation.class);
18. if (access == null) {
19. // 如果注解为null,没有注解 不拦截
20. return true;
21.         }
22. //获取注解值
23. if (access.authorities().length > 0) {
24. // 如果权限配置不为空, 则取出配置值
25. String[] authorities = access.authorities();
26.         }
27. // 拦截之后应该返回公共结果, 这里没做处理
28. return true;
29.     }
30. }

1. package com.airboot.bootdemo.config;
2. 
3. 
4. import org.springframework.context.annotation.Configuration;
5. import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
6. import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
7. 
8. @Configuration
9. public class InterceptorConfig extends WebMvcConfigurerAdapter {
10. @Override
11.     public void addInterceptors(InterceptorRegistry registry) {
12.         registry.addInterceptor(new TestAnnotationInterceptor()).addPathPatterns("/**");
13.     }
14. }

1. @RequestMapping(value = "/selectDemoByVo")
2. @InterceptorAnnotation(authorities = {"admin"})
3. public List<DemoVO> selectDemoByVo(@RequestBody DemoVO demoVO) {
4. return demoService.selectDemoVO(demoVO);
5.     }

1. import javax.validation.Constraint;
2. import javax.validation.Payload;
3. import java.lang.annotation.*;
4. 
5. @Target({ElementType.METHOD, ElementType.FIELD})
6. @Retention(RetentionPolicy.RUNTIME)
7. @Documented
8. @Constraint(validatedBy = TestConstraintValidator.class)
9. public @interface TestConstraintAnnotation {
10. 
11.     String message() default "入参大小不合适";
12. 
13. long min();
14. 
15. long max();
16. 
17. boolean required() default true;
18. 
19.     Class<?>[] groups() default {};
20. 
21.     Class<? extends Payload>[] payload() default {};
22. 
23. }

1. public class TestConstraintValidator implements ConstraintValidator<TestConstraintAnnotation, Object> {
2. private long max = 1;
3. private long min = 1;
4. 
5. @Override
6. public void initialize(TestConstraintAnnotation constraintAnnotation) {
7.         max = constraintAnnotation.max();
8.         min = constraintAnnotation.min();
9.     }
10. 
11. @Override
12. public boolean isValid(Object o, ConstraintValidatorContext constraintValidatorContext) {
13. if(o == null){
14. return true;
15.         }
16. if(Long.valueOf(o.toString())>=min && Long.valueOf(o.toString())<=max){
17. return true;
18.         }
19. return false;
20.     }
21. }

1. @RequestMapping(value = "/selectDemoByVo")
2. public List<DemoVO> selectDemoByVo(@Valid @RequestBody DemoVO demoVO) {
3. return demoService.selectDemoVO(demoVO);
4.     }
5. 
6. 
7. @TestConstraintAnnotation(min = 1, max = 10)
8. private Long id;