在系统中使用Bean Validation验证参数

转自：http://www.importnew.com/18561.html

为什么要使用Bean Validation？

当我们实现某个接口时，都需要对入参数进行校验。例如下面的代码

public String queryValueByKey(String parmTemplateCode, String conditionName, String conditionKey, String resultName) {

checkNotNull(parmTemplateCode, "parmTemplateCode not null");

checkNotNull(conditionName, "conditionName not null");

checkNotNull(conditionKey, "conditionKey not null");

checkNotNull(resultName, "resultName not null");

该方法输入的四个参数都是必填项。用代码进行参数验证带来几个问题

需要写大量的代码来进行参数验证。
需要通过注释来直到每个入参的约束是什么。
每个程序员做参数验证的方式不一样，参数验证不通过抛出的异常也不一样。

什么是Bean Validation？

Bean Validation是一个通过配置注解来验证参数的框架，它包含两部分Bean Validation API和Hibernate Validator。

Bean Validation API是Java定义的一个验证参数的规范。
Hibernate Validator是Bean Validation API的一个实现。

快速开始

引入POM

<dependency>

<groupId>org.hibernate</groupId>

<artifactId>hibernate-validator</artifactId>

<version>5.1.1.Final</version>

</dependency>

<dependency>

<groupId>javax.validation</groupId>

<artifactId>validation-api</artifactId>

<version>1.1.0.Final</version>

</dependency>

<dependency>

<groupId>javax.el</groupId>

<artifactId>el-api</artifactId>

<version>2.2</version>

</dependency>

<dependency>

<groupId>org.glassfish.web</groupId>

<artifactId>javax.el</artifactId>

<version>2.2.4</version>

</dependency>

<dependency>

<groupId>org.jboss.logging</groupId>

<artifactId>jboss-logging</artifactId>

<version>3.1.3.GA</version>

</dependency>

<dependency>

<groupId>com.fasterxml</groupId>

<artifactId>classmate</artifactId>

<version>1.0.0</version>

</dependency>

<dependency>

<groupId>log4j</groupId>

<artifactId>log4j</artifactId>

<version>1.2.13</version>

</dependency>

实例代码如下，可以验证Bean，也可以验证方法参数

import java.lang.reflect.Method;

import java.util.Set;

import javax.validation.ConstraintViolation;

import javax.validation.Validation;

import javax.validation.Validator;

import javax.validation.constraints.Max;

import javax.validation.constraints.NotNull;

import javax.validation.executable.ExecutableValidator;

public class BeanValidatorTest {

public static void main(String[] args) {

Validator validator = Validation.buildDefaultValidatorFactory().getValidator();

//验证Bean参数，并返回验证结果信息

Car car = new Car();

Set<ConstraintViolation<Car>> validators = validator.validate(car);

for (ConstraintViolation<Car> constraintViolation : validators) {

System.out.println(constraintViolation.getMessage());

}

// 验证方法参数

Method method = null;

try {

method = Car.class.getMethod("drive", int.class);

} catch (SecurityException e) {

} catch (NoSuchMethodException e) {

}

Object[] parameterValues = { 80 };

ExecutableValidator executableValidator = validator.forExecutables();

Set<ConstraintViolation<Car>> methodValidators = executableValidator.validateParameters(car,

method, parameterValues);

for (ConstraintViolation<Car> constraintViolation : methodValidators) {

System.out.println(constraintViolation.getMessage());

}

public static class Car {

private String name;

@NotNull(message = "车主不能为空")

public String getRentalStation() {

return name;

}

public void drive(@Max(75) int speedInMph) {

}

执行代码后，输出如下：

1 2	`车主不能为空` `最大不能超过75`

使用代码验证方法参数

Validation验证不成功可能返回多个验证错误信息，我们可以包装下，当有错误时直接返回第一个错误的异常。

import static com.google.common.collect.Iterables.getFirst;

import java.util.Set;

import javax.validation.ConstraintViolation;

import javax.validation.Validation;

import javax.validation.Validator;

/**

* 对象验证器

*

* @author tengfei.fangtf

* @version $Id: BeanValidator.java, v 0.1 Dec 30, 2015 11:33:40 PM tengfei.fangtf Exp $

*/

public class BeanValidator {

/**

* 验证某个bean的参数

*

* @param object 被校验的参数

* @throws ValidationException 如果参数校验不成功则抛出此异常

*/

public static <T> void validate(T object) {

//获得验证器

Validator validator = Validation.buildDefaultValidatorFactory().getValidator();

//执行验证

Set<ConstraintViolation<T>> constraintViolations = validator.validate(object);

//如果有验证信息，则将第一个取出来包装成异常返回

ConstraintViolation<T> constraintViolation = getFirst(constraintViolations, null);

if (constraintViolation != null) {

throw new ValidationException(constraintViolation);

}

我们可以在每个方法的第一行调用BeanValidator.validate来验证参数，测试代码如下,

import static junit.framework.Assert.assertEquals;

import javax.validation.constraints.Max;

import javax.validation.constraints.NotNull;

import org.junit.Test;

/**

*

* @author tengfei.fangtf

* @version $Id: BeanValidatorTest.java, v 0.1 Dec 30, 2015 11:33:56 PM tengfei.fangtf Exp $

*/

public class BeanValidatorTest {

@Test

public void test() {

try {

BeanValidator.validate(new Car());

} catch (Exception e) {

assertEquals("rentalStation 车主不能为空", e.getMessage());

}

public static class Car {

private String name;

@NotNull(message = "车主不能为空")

public String getRentalStation() {

return name;

}

public void drive(@Max(75) int speedInMph) {

}

使用拦截器验证方法参数

我们在对外暴露的接口的入参中使用Bean Validation API配置参数约束，如下XXXService接口

public interface XXXService {

GetObjectResponse getObject(GetObjectRequest getObjectRequest);

}

在getObject的GetObjectRequest参数中配置注解来约束参数。

public class GetObjectRequest {

@Valid

@NotNull

private ObjectKey objectKey;

@Size(max = 9)

private Map<String, Object> parameters;

@AssertTrue

public boolean isEntityNameOrCodeAtLeastOneIsNotBlank() {

return isNotBlank(entityName) || isNotBlank(entityCode);

}

//代码省略

}

编写参数验证拦截器，当方法被调用时，触发Validator验证器执行验证，如果不通过则抛出ParameterValidationException。

import static com.google.common.collect.Iterables.getFirst;

import java.util.Set;

import javax.validation.ConstraintViolation;

import javax.validation.Validation;

import javax.validation.Validator;

import org.aopalliance.intercept.MethodInterceptor;

import org.aopalliance.intercept.MethodInvocation;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import com.xx.ParameterValidationException;

/**

* 参数验证拦截器，基于JSR-303 BeanValidation

*

* @author tengfei.fangtf

*

* @version $Id: TitanValidateInterceptor.java, v 0.1 Nov 23, 2015 11:13:55 PM tengfei.fangtf Exp $

*/

public class TitanValidateInterceptor implements MethodInterceptor {

private static final Logger LOGGER = LoggerFactory.getLogger(TitanValidateInterceptor.class);

private final Validator validator;

public TitanValidateInterceptor() {

validator = Validation.buildDefaultValidatorFactory().getValidator();

}

@Override

public Object invoke(MethodInvocation invocation) throws Throwable {

if (LOGGER.isDebugEnabled()) {

LOGGER.debug("Validate arguments");

}

//获取参数，并检查是否应该验证

Object[] arguments = invocation.getArguments();

for (Object argument : arguments) {

if (LOGGER.isDebugEnabled()) {

LOGGER.debug("Validate argument: {}", argument);

}

Set<ConstraintViolation<Object>> constraintViolations = validator.validate(argument);

ConstraintViolation<Object> constraintViolation = getFirst(constraintViolations, null);

if (constraintViolation == null) {

continue;

}

if (LOGGER.isInfoEnabled()) {

LOGGER.info("ConstraintViolation: {}", constraintViolation);

}

throw new ParameterValidationException(constraintViolation.getPropertyPath() + " " + constraintViolation.getMessage());

}

return invocation.proceed();

}

配置拦截器core-service.xml，拦截XXXService的所有方法。

<?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:p="http://www.springframework.org/schema/p"

xmlns:context="http://www.springframework.org/schema/context"

xmlns:webflow="http://www.springframework.org/schema/webflow-config"

xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd

http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd

http:

//www.springframework.org/schema/webflow-config http://www.springframework.org/schema/webflow-config/spring-webflow-config-2.0.xsd"

default-autowire="byName">

<bean id="XXXService" class="org.springframework.aop.framework.ProxyFactoryBean">

<property name="target">

<bean class="com.XXXService" />

</property>

<property name="interceptorNames">

<list>

<value>validateInterceptor</value>

</list>

</property>

</bean>

<bean id="validateInterceptor"

class="com.mybank.bkloanapply.common.validator.ValidateInterceptor" />

</beans>

参考资料