参数注解检查方法入参
作者：互联网
springboot 中 @NotNull 等参数检查注解非常实用，优化掉了很多的重复代码。
在开发老版本 spring 项目时，没有类似注解，所以自己实现一个类似的功能，优化代码结构。
由于项目中没有使用统一异常处理，注解用于 Service 层，抛出的异常由 Controller 处理。
首先自定义注解：
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD})
public @interface CheckParams {
}
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.FIELD, ElementType.PARAMETER})
public @interface NotNull {
String message() default "";
ParamType type() default ParamType.VALUE;
}
@CheckParams 注解用做切点，@NotNull 注解标注参数。切面实现：
@Aspect
@Component
public class ParamsCheckAspect {
private static final Logger logger = Logger.getLogger(ParamsCheckAspect.class);
ControllerUtils controllerUtils = new ControllerUtils();
//切点
@Pointcut("@annotation(com.inspur.paramsCheck.annotation.CheckParams)")
public void CheckParamsAspect() {
}
//切面
@Around("CheckParamsAspect()")
public Object check(ProceedingJoinPoint joinPoint) throws IllegalAccessException, Throwable {
Object[] args = joinPoint.getArgs();
Method method = ((MethodSignature) joinPoint.getSignature()).getMethod();
Annotation[][] paramsAnnotation = method.getParameterAnnotations();
if (null != paramsAnnotation && paramsAnnotation.length != 0) {
for (int i = 0; i < paramsAnnotation.length; i++) {
Annotation[] annotations = paramsAnnotation[i];
if (null == annotations || annotations.length == 0) continue;
int notNullPoint = -1;
if ((notNullPoint = this.indexOf(annotations, NotNull.class.getName())) != -1) {
Object arg = args[i];
NotNull notNull = (NotNull) annotations[notNullPoint];
if (notNull.type() == ParamType.VALUE && isNull(arg)) {
throw new LackParamException(notNull.message());
}
if (notNull.type() == ParamType.BEAN) this.checkBean(arg, new HashSet<Object>());
}
}
}
return joinPoint.proceed(args);
}
/**
* @Author
* @Date 2021/10/2 下午11:53
* @Description 递归检查对象完整性
*/
private void checkBean(Object o, Set<Object> hisSet) throws IllegalAccessException {
//终止条件，处理循环依赖
if (hisSet.contains(o)) return;
hisSet.add(o);
Class clazz = o.getClass();
String className = clazz.getSimpleName();
Field[] fields = o.getClass().getDeclaredFields();
for (Field field : fields) {
if (!field.isAnnotationPresent(NotNull.class)) continue;
NotNull notNull = field.getAnnotation(NotNull.class);
ParamType type = notNull.type();
if (type == ParamType.VALUE && this.isNull(o, field)) {
throw new LackParamException(className + ":" + notNull.message());
}
if (type == ParamType.BEAN) {
field.setAccessible(true);
Object bean = field.get(o);
if (null == bean) throw new LackParamException(className + ":" + notNull.message());
this.checkBean(bean, hisSet);
}
}
}
private int indexOf(Annotation[] arr, String annotationName) {
for (int i = 0; i < arr.length; i++) {
Annotation annotation = arr[i];
String name = annotation.annotationType().getName();
if (name.equals(annotationName)) return i;
}
return -1;
}
private boolean isNull(Object obj, Field field) throws IllegalAccessException {
field.setAccessible(true);
Object value = field.get(obj);
return isNull(value);
}
private boolean isNull(Object obj) {
return null == obj || obj.toString().length() == 0;
}
}
测试，定义 bean：
public class selectMachineVisitNumDto extends BasePo {
@NotNull(message = "regionCode不可为空")
private String regionCode;
@NotNull(message = "machineType不可为空")
private String machineType;
@NotNull(message = "startTime不可为空")
private String startTime;
@NotNull(message = "endTime不可为空")
private String endTime;
@NotNull(type = ParamType.BEAN)
private TestDto testDto;
public TestDto getTestDto() {
return testDto;
}
public void setTestDto(TestDto testDto) {
this.testDto = testDto;
}
public String getRegionCode() {
return regionCode;
}
public void setRegionCode(String regionCode) {
this.regionCode = regionCode;
}
public String getMachineType() {
return machineType;
}
public void setMachineType(String machineType) {
this.machineType = machineType;
}
public String getStartTime() {
return startTime;
}
public void setStartTime(String startTime) {
this.startTime = startTime;
}
public String getEndTime() {
return endTime;
}
public void setEndTime(String endTime) {
this.endTime = endTime;
}
}
public class TestDto {
@NotNull(message = "test不可为空！")
private String test;
@NotNull(type = ParamType.BEAN)
private selectMachineVisitNumDto selectMachineVisitNumDto;
public com.inspur.approval.selfstatistic.dto.selectMachineVisitNumDto getSelectMachineVisitNumDto() {
return selectMachineVisitNumDto;
}
public void setSelectMachineVisitNumDto(com.inspur.approval.selfstatistic.dto.selectMachineVisitNumDto selectMachineVisitNumDto) {
this.selectMachineVisitNumDto = selectMachineVisitNumDto;
}
public String getTest() {
return test;
}
public void setTest(String test) {
this.test = test;
}
@Override
public String toString() {
JSONObject jsonObject = new JSONObject();
jsonObject.put("test", test);
jsonObject.put("selectMachineVisitNumDto", selectMachineVisitNumDto.toString());
return jsonObject.toJSONString();
}
}
两个 bean 之间可形成循环依赖。Service 层，使用 @NotNull 标注参数，@CheckParams 标注方法：
@CheckParams
public String getMachineNum(@NotNull(type = ParamType.BEAN) selectMachineVisitNumDto dto, @NotNull(message =
"name不可为空!") String name) throws Exception {
JSONObject jsonObject = dto.toJSON();
return jsonObject.toJSONString();
}
Controller 进行异常捕获及处理：
@RequestMapping("test")
@ResponseBody
public String getMachineNum(selectMachineVisitNumDto dto, String name, String test) {
try {
TestDto testDto = new TestDto();
testDto.setTest(test);
testDto.setSelectMachineVisitNumDto(dto);
dto.setTestDto(testDto);
String res = selfStatisticService.getMachineNum(dto, name);
return controllerUtils.getSuccessJson(res).toJSONString();
} catch (Exception e) {
logger.error(e.getMessage(), e);
return controllerUtils.getErrorJson(e.getMessage()).toJSONString();
}
}
测试，dto 参数缺失：
递归检查 TestDto 中参数缺失：
两个 bean 的参数均完整，测试循环依赖情况的处理：
可以看到，已经跳出了对两个 dto 的检查，没有陷入循环依赖中。将单独参数 name 补充完整：
标签：return,String,selectMachineVisitNumDto,private,入参,参数,NotNull,注解,public 来源： https://www.cnblogs.com/niuyourou/p/15365321.html