前言
架构是网关直接通过泛化调用Dubbo服务，不同于web Controller使用spring mvc模块来做到参数注解校验。不过不用担心Dubbo也考虑到了这一点，基于SPI机制提供了ValidationFilter
那我们就来看看他是如何实现的。
Dubbo源码实现
Dubbo SPI定义
你可能要问问了什么是Dubbo SPI，嗯…这个嘛，简单说是通过文件配置对应class路径后会被执行class里的invoke函数。其中的实现原理大家顺着Dubbo的ExtensionLoader去看下源码就能知道。
ValidationFilter说明
//在哪种服务类型激活
//这里的VALIDATION_KEY=“validation” 也就是我们在SPI中需要把key按这个规定定义
@Activate(group = {CONSUMER, PROVIDER}, value = VALIDATION_KEY, order = 10000)
public class ValidationFilter implements Filter {
private Validation validation;
public void setValidation(Validation validation) {
this.validation = validation;
}
@Override
public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {
//如果SPI中定义了validation 那么就进行校验
if (validation != null && !invocation.getMethodName().startsWith("$")
&& ConfigUtils.isNotEmpty(invoker.getUrl().getMethodParameter(invocation.getMethodName(), VALIDATION_KEY))) {
try {
//执行参数校验
Validator validator = validation.getValidator(invoker.getUrl());
if (validator != null) {
validator.validate(invocation.getMethodName(), invocation.getParameterTypes(), invocation.getArguments());
}
} catch (RpcException e) {
throw e;
} catch (ValidationException e) {
//抛出异常 这里的ValidationException需要深挖一下，后面会说
// only use exception's message to avoid potential serialization issue
return AsyncRpcResult.newDefaultAsyncResult(new ValidationException(e.getMessage()), invocation);
} catch (Throwable t) {
return AsyncRpcResult.newDefaultAsyncResult(t, invocation);
}
}
return invoker.invoke(invocation);
}
}
基础使用
maven 依赖
springboot项目推荐使用
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-validation</artifactId>
</dependency>
手动依赖
<dependency>
<groupId>javax.el</groupId>
<artifactId>javax.el-api</artifactId>
<version>3.0.0</version>
</dependency>
<dependency>
<groupId>org.glassfish</groupId>
<artifactId>javax.el</artifactId>
</dependency>
<dependency>
<groupId>javax.validation</groupId>
<artifactId>validation-api</artifactId>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-validator</artifactId>
</dependency>
DTO添加validation定义
import lombok.Data;
import javax.validation.constraints.NotBlank;
import javax.validation.constraints.NotNull;
import java.io.Serializable;
@Data
public class PracticeParam implements Serializable {
@NotNull(message = "periodId不能为空")
private Long periodId;
}
服务提供者interface
public interface IPracticeService {
boolean practiceAdd(PracticeParam practiceParam);
}
Dubbo RPC单元测试
@SpringBootTest(classes = ClientApplication.class)
@RunWith(SpringRunner.class)
@Slf4j
public class PrecticeTest {
@DubboReference(group = "user")
private IPracticeService practiceLogicService;
@Test
public void add(){
PracticeParam practiceParam=new PracticeParam();
log.info(String.valueOf(practiceLogicService.practiceAdd(practiceParam)));
}
}
测试结果
javax.validation.ValidationException: Failed to validate service: com.xx.contract.IPracticeService, method: practiceAdd, cause: [ConstraintViolationImpl{interpolatedMessage='periodId不能为空', propertyPath=periodId, rootBeanClass=class com.xx.request.PracticeParam, messageTemplate='periodId不能为空'}]
嗯 看来是生效了，不过这和我们实际项目中还有些距离。不能把这个异常抛给网关，根据项目需要适配上我们的全局异常试试吧。
源码分析与扩展
Dubbo异常处理
再回到前面SPI文件
ExceptionFilter源码分析
//在服务提供者端生效
@Activate(group = CommonConstants.PROVIDER)
public class ExceptionFilter implements Filter, Filter.Listener {
private Logger logger = LoggerFactory.getLogger(ExceptionFilter.class);
@Override
public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {
return invoker.invoke(invocation);
}
@Override
public void onResponse(Result appResponse, Invoker<?> invoker, Invocation invocation) {
//异常处理逻辑
if (appResponse.hasException() && GenericService.class != invoker.getInterface()) {
try {
Throwable exception = appResponse.getException();
// directly throw if it's checked exception
if (!(exception instanceof RuntimeException) && (exception instanceof Exception)) {
return;
}
// directly throw if the exception appears in the signature
try {
Method method = invoker.getInterface().getMethod(invocation.getMethodName(), invocation.getParameterTypes());
Class<?>[] exceptionClassses = method.getExceptionTypes();
for (Class<?> exceptionClass : exceptionClassses) {
if (exception.getClass().equals(exceptionClass)) {
return;
}
}
} catch (NoSuchMethodException e) {
return;
}
// for the exception not found in method's signature, print ERROR message in server's log.
logger.error("Got unchecked and undeclared exception which called by " + RpcContext.getContext().getRemoteHost() + ". service: " + invoker.getInterface().getName() + ", method: " + invocation.getMethodName() + ", exception: " + exception.getClass().getName() + ": " + exception.getMessage(), exception);
// directly throw if exception class and interface class are in the same jar file.
String serviceFile = ReflectUtils.getCodeBase(invoker.getInterface());
String exceptionFile = ReflectUtils.getCodeBase(exception.getClass());
if (serviceFile == null || exceptionFile == null || serviceFile.equals(exceptionFile)) {
return;
}
// directly throw if it's JDK exception
String className = exception.getClass().getName();
if (className.startsWith("java.") || className.startsWith("javax.")) {
return;
}
// directly throw if it's dubbo exception
if (exception instanceof RpcException) {
return;
}
// otherwise, wrap with RuntimeException and throw back to the client
//重点时这句，替换异常信息
appResponse.setException(new RuntimeException(StringUtils.toString(exception)));
} catch (Throwable e) {
logger.warn("Fail to ExceptionFilter when called by " + RpcContext.getContext().getRemoteHost() + ". service: " + invoker.getInterface().getName() + ", method: " + invocation.getMethodName() + ", exception: " + e.getClass().getName() + ": " + e.getMessage(), e);
}
}
}
@Override
public void one rror(Throwable e, Invoker<?> invoker, Invocation invocation) {
logger.error("Got unchecked and undeclared exception which called by " + RpcContext.getContext().getRemoteHost() + ". service: " + invoker.getInterface().getName() + ", method: " + invocation.getMethodName() + ", exception: " + e.getClass().getName() + ": " + e.getMessage(), e);
}
// For test purpose
public void setLogger(Logger logger) {
this.logger = logger;
}
}
项目定制化扩展
定义SPI
项目结构说明
文件定义（Dubbo SPI需要严格按如下路径和文件名）
src/main/resources/META-INF/dubbo/org.apache.dubbo.rpc.Filter
文件内容
validation=com.xx.xx.config.DubboValidationFilter
exception=com.xx.xx.config.DubboExceptionFilter
自定义DubboValidationFilter
import com.xx.exception.ParamException;
import org.apache.dubbo.common.extension.Activate;
import org.apache.dubbo.common.utils.ConfigUtils;
import org.apache.dubbo.rpc.*;
import org.apache.dubbo.validation.Validation;
import org.apache.dubbo.validation.Validator;
import javax.validation.ConstraintViolation;
import javax.validation.ConstraintViolationException;
import java.util.Set;
import static org.apache.dubbo.common.constants.CommonConstants.PROVIDER;
import static org.apache.dubbo.common.constants.FilterConstants.VALIDATION_KEY;
@Activate(group = {PROVIDER}, value = VALIDATION_KEY, order = -1)
public class DubboValidationFilter implements Filter {
private Validation validation;
public void setValidation(Validation validation) {
this.validation = validation;
}
@Override
public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {
if (validation != null && !invocation.getMethodName().startsWith("$")
&& ConfigUtils.isNotEmpty(invoker.getUrl().getMethodParameter(invocation.getMethodName(), VALIDATION_KEY))) {
try {
Validator validator = validation.getValidator(invoker.getUrl());
if (validator != null) {
//挖掘点 validate函数的源码
validator.validate(invocation.getMethodName(), invocation.getParameterTypes(), invocation.getArguments());
}
}
//Dubbo源码里捕获的是ValidationException这个异常,原始信息变成了字符串，所以接下来
//通过JValidator源码分析进行如下扩展
catch (ConstraintViolationException e) {
//获取我们的异常，这里的异常时集合的，因为我们参数可能多个都不通过
StringBuilder message = new StringBuilder();
Set<ConstraintViolation<?>> violations = e.getConstraintViolations();
for (ConstraintViolation<?> violation : violations) {
//这里只获取第一个不通过的原因
message.append(violation.getMessage().concat(";"));
break;
}
//项目自定义异常类型，网关可以捕获到该异常
throw new ParamException(message.toString());
} catch (RpcException e) {
throw e;
} catch (Throwable t) {
return AsyncRpcResult.newDefaultAsyncResult(t, invocation);
}
}
return invoker.invoke(invocation);
}
}
JValidator源码分析
//Validated 校验过程
public void validate(String methodName, Class<?>[] parameterTypes, Object[] arguments) throws Exception {
List<Class<?>> groups = new ArrayList<>();
Class<?> methodClass = methodClass(methodName);
if (methodClass != null) {
groups.add(methodClass);
}
//异常返回信息 violations
Set<ConstraintViolation<?>> violations = new HashSet<>();
Method method = clazz.getMethod(methodName, parameterTypes);
Class<?>[] methodClasses;
if (method.isAnnotationPresent(MethodValidated.class)){
methodClasses = method.getAnnotation(MethodValidated.class).value();
groups.addAll(Arrays.asList(methodClasses));
}
// add into default group
groups.add(0, Default.class);
groups.add(1, clazz);
// convert list to array
Class<?>[] classgroups = groups.toArray(new Class[groups.size()]);
Object parameterBean = getMethodParameterBean(clazz, method, arguments);
if (parameterBean != null) {
violations.addAll(validator.validate(parameterBean, classgroups ));
}
for (Object arg : arguments) {
validate(violations, arg, classgroups);
}
if (!violations.isEmpty()) {
logger.error("Failed to validate service: " + clazz.getName() + ", method: " + methodName + ", cause: " + violations);
//这里原始异常是它，所以我们需要捕获它，得到violations
throw new ConstraintViolationException("Failed to validate service: " + clazz.getName() + ", method: " + methodName + ", cause: " + violations, violations);
}
}
自定义DubboExceptionFilter
@Slf4j
@Activate(group = CommonConstants.PROVIDER)
public class DubboExceptionFilter extends ExceptionFilter {
@Override
public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {
return invoker.invoke(invocation);
}
@Override
public void onResponse(Result appResponse, Invoker<?> invoker, Invocation invocation) {
log.error("dubbo global exception ---------->{}", appResponse.getException());
if (appResponse.hasException() && GenericService.class != invoker.getInterface()) {
try {
Throwable exception = appResponse.getException();
// 自定义异常处理
if (exception instanceof ParamException) {
//按项目log收集规范输出
log.error("dubbo service exception ---------->{}", exception);
return;
}
......
} catch (Throwable e) {
log.warn("Fail to ExceptionFilter when called by " + RpcContext.getContext().getRemoteHost() + ". service: " + invoker.getInterface().getName() + ", method: " + invocation.getMethodName() + ", exception: " + e.getClass().getName() + ": " + e.getMessage(), e);
}
}
}
}
RPC单元测试
org.apache.dubbo.remoting.RemotingException: com.xx.exception.ParamException: periodId不能为空;
com.xx.exception.ParamException: periodId不能为空;
高级进阶
我们在业务里一个DTO对象会用于新增或更新，在新增时不需要主键ID，在更新时需要主键ID。
那我们就需要引入分组的概念了
定义validation groups
在API模块中定义两个分组
//用于新增
public interface InsertValidation {
}
//用于更新
public interface UpdateValidation {
}
定义DTO
@Data
public class PracticeParam implements Serializable {
//只用于更新
@NotNull(groups={UpdateValidation.class},message = "id不能为空")
private Integer id;
// 如果两组校验都需要可以省去group的定义，完整的如下
// @NotBlank(groups={InsertValidation.class, UpdateValidation.class},message = "名称不能为空")
@NotNull(message = "periodId不能为空")
private Long periodId;
}
服务提供者interface
public interface IPracticeService {
//因为periodId参数是默认不区分组的，所以这里省去了Validated注解
boolean practiceAdd(PracticeParam practiceParam);
boolean practiceEdit(@Validated(value = {UpdateValidation.class}) PracticeParam practiceParam);
}
完工，这样我们就齐活了，截个图看看真实运行情况吧
生产环境验证
感谢您的耐心看到这里，学海无涯继续奋斗！