继承spring的validator接口，实现对数据的校验

　　在org.springframework.validation这个包中提供了一些对数据校验的方法，其中Validator接口是其中的一个。

现在用Validator接口，完成对数据的校验.

第一步：先定义一个domain对象：Person:

Person的代码如下：

package com.validation;

public class Person {

    private String name;

    private Integer age;

    public String getName() {

        return name;

    }

    public void setName(String name) {

        this.name = name;

    }

    public Integer getAge() {

        return age;

    }

    public void setAge(Integer age) {

        this.age = age;

    }

}

第二步定义PersonValidator类，这个类继承了Validator这个类：

package com.validation;

import org.springframework.validation.Errors;

import org.springframework.validation.ValidationUtils;

import org.springframework.validation.Validator;

public class PersonValidator implements Validator {

    @Override

    public boolean supports(Class<?> clazz) {

        return Person.class.equals(clazz);

    }

    @Override

    public void validate(Object obj, Errors e) {

        ValidationUtils.rejectIfEmpty(e, "name", "name.empty");

        Person p = (Person) obj;

        if (p.getAge() < ) {

            e.rejectValue("age", "negativevalue");

        } else if (p.getAge() > ) {

            e.rejectValue("age", "too.darn.old");

        }

    }

}

第三步：controller层的代码如下：

package com.validation;

import com.entity.Bar;

import com.entity.BarValidator;

import com.entity.Foo;

import org.springframework.beans.PropertyValues;

import org.springframework.validation.BindException;

import org.springframework.validation.BindingResult;

import org.springframework.validation.DataBinder;

import org.springframework.validation.ObjectError;

import org.springframework.validation.annotation.Validated;

import org.springframework.web.bind.WebDataBinder;

import org.springframework.web.bind.annotation.InitBinder;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;

import javax.validation.Valid;

import java.util.List;

@RestController

public class FooController {

    @RequestMapping("/peopleTest")

    public String people(Person person){

        PersonValidator validator = new PersonValidator();

        if(validator.supports(Person.class)){

            BindException errors = new BindException(person, "person");

            validator.validate(person,errors);

            List<ObjectError> allErrors = errors.getAllErrors();

            System.out.println("size="+allErrors.size());

            for (int i=;i<allErrors.size();i++) {

                System.out.println(allErrors.get(i).getCode());

            }

        }

        return "success";

    }

}

第四步：springboot的启动类的代码如下：

package com.validation;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;

@SpringBootApplication(exclude={DataSourceAutoConfiguration.class})

public class Application {

    public static void main(String[] args) {

        SpringApplication.run(Application.class,args);

    }

}

第五步：在浏览器的地址栏中输入：http://localhost:8080/peopleTest?age=200  注意这里的age如果不写的话,会报NullPointException.如你只写为：http://localhost:8080/peopleTest

输出结果为：

size=2
name.empty
too.darn.old