使用jsr validation动态代理验证java bean，jsrvalidation,新建项目， 在pom文件

使用jsr validation动态代理验证java bean，jsrvalidation,新建项目， 在pom文件

新建项目， 在pom文件中添加如下maven依赖

        <dependency>            <groupId>javax.validation</groupId>            <artifactId>validation-api</artifactId>            <version>1.1.0.Final</version>        </dependency>        <dependency>            <groupId>org.hibernate</groupId>            <artifactId>hibernate-validator</artifactId>            <version>5.2.1.Final</version>        </dependency>        <dependency>            <groupId>org.hibernate</groupId>            <artifactId>hibernate-validator-annotation-processor</artifactId>            <version>5.2.1.Final</version>        </dependency>        <dependency>            <groupId>javax.el</groupId>            <artifactId>javax.el-api</artifactId>            <version>2.2.4</version>        </dependency>

如下是使用validation验证bean的使用示例：

package cn.outofmemory.hello;import org.hibernate.validator.constraints.Email;import javax.validation.ConstraintViolation;import javax.validation.Valid;import javax.validation.Validation;import javax.validation.Validator;import javax.validation.constraints.NotNull;import javax.validation.constraints.Size;import java.lang.annotation.Annotation;import java.lang.reflect.InvocationHandler;import java.lang.reflect.Method;import java.lang.reflect.Proxy;import java.util.Set;/** * Created by byrx.net on 2016/6/28. */public class HelloValidator {    public static class Student {        private int id;        @NotNull        @Size(max = 20, min=2, message = "student name length must between 2 to 20")        private String name;        @NotNull        @Email        private String email;        public int getId() {            return id;        }        public void setId(int id) {            this.id = id;        }        public String getName() {            return name;        }        public void setName(String name) {            this.name = name;        }        public String getEmail() {            return email;        }        public void setEmail(String email) {            this.email = email;        }    }    public static void main(String[] args) {        Student student = new Student();        student.setName("a");        student.setEmail("ah");////        ValidatorFactory validatorFactory = Validation.buildDefaultValidatorFactory();//        Validator validator = validatorFactory.getValidator();//        Set<ConstraintViolation<Student>>  violations = validator.validate(student);//        for (ConstraintViolation<Student> violation : violations) {//            System.out.println(violation.getMessage());//        }        AService aService = (AService) Proxy.newProxyInstance(                HelloValidator.class.getClassLoader(),                new Class[]{AService.class},                new ValidationInvocationHandler(new AServiceImpl())                );        aService.processStudent(student);    }    public interface AService {        void processStudent(@Valid Student student);    }    public static class AServiceImpl implements  AService{        public void processStudent(Student student) {            System.out.println("do something");        }    }    public static class ValidationInvocationHandler implements InvocationHandler {        static final Validator validator = Validation.buildDefaultValidatorFactory().getValidator();        final Object proxyTarget;        public ValidationInvocationHandler(final Object target) {            proxyTarget = target;        }        @Override        public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {            Annotation[][] annotations = method.getParameterAnnotations();            for (int parameterIndex = 0; parameterIndex < args.length; parameterIndex++) {                Annotation[] parameterAnnotations = annotations[parameterIndex];                for(Annotation parameterAnnotation : parameterAnnotations) {                    if (parameterAnnotation.annotationType().isAssignableFrom(Valid.class)) {                        //we need validate this parameter                        Object parameter = args[parameterIndex];                        Set<ConstraintViolation<Object>>  violations = validator.validate(parameter);                        if (violations.size() > 0) {                            for (ConstraintViolation<Object> violation : violations) {                                System.out.println(violation.getMessage());                            }                        }                    }                }            }            return method.invoke(proxyTarget, args);        }    }}