关于spring中的validate注解后台校验的解析

在后台开发过程中，对参数的校验成为开发环境不可缺少的一个环节。比如参数不能为null，email那么必须符合email的格式，如果手动进行if判断或者写正则表达式判断无意开发效率太慢，在时间、成本、质量的博弈中必然会落后。所以把校验层抽象出来是必然的结果，下面说下几种解决方案。

1.简单的校验Demo

依赖:

         
      
       javax.validation
          
      
       validation-api
          
      
       1.1.0.Final
      
     

Student:

import javax.validation.constraints.*;import java.math.BigDecimal;import java.util.Date;public class Student {        @NotNull(message = "名字不能为空")        private String name;        @Size(min = 6, max = 30, message = "地址应该在6-30字符之间")        private String address;        @DecimalMax(value = "100.00", message = "体重有些超标哦")        @DecimalMin(value = "60.00", message = "多吃点饭吧")        private BigDecimal weight;        private String friendName;        @AssertTrue        private Boolean isHaveFriend() {            return friendName != null ? true : false;        }        @Future(message = "生日必须在当前实践之前")        private Date birthday;        @Pattern(regexp = "^(.+)@(.+)$", message = "邮箱的格式不合法")        private String email;        public String getName() {            return name;        }        public void setName(String name) {            this.name = name;        }        public String getAddress() {            return address;        }        public void setAddress(String address) {            this.address = address;        }        public BigDecimal getWeight() {            return weight;        }        public void setWeight(BigDecimal weight) {            this.weight = weight;        }        public String getFriendName() {            return friendName;        }        public void setFriendName(String friendName) {            this.friendName = friendName;        }        public Date getBirthday() {            return birthday;        }        public void setBirthday(Date birthday) {            this.birthday = birthday;        }        public String getEmail() {            return email;        }        public void setEmail(String email) {            this.email = email;        }    }

DemoTest:

import javax.validation.*;import java.math.BigDecimal;import java.util.ArrayList;import java.util.Date;import java.util.List;import java.util.Set;public class DemoTest {        public static void main(String[] args) {            Student xiaoming = getBean();            List
     
       validate = validate(xiaoming);            validate.forEach(row -> {                System.out.println(row.toString());            });        }        private static Student getBean() {            Student bean = new Student();            bean.setName(null);            bean.setAddress("北京");            bean.setBirthday(new Date());            bean.setFriendName(null);            bean.setWeight(new BigDecimal(30));            bean.setEmail("xiaogangfan163.com");            return bean;        }        private static ValidatorFactory factory = Validation.buildDefaultValidatorFactory();        public static 
      
        List
       
         validate(T t) {            Validator validator = factory.getValidator();            Set
        
         
          > constraintViolations = validator.validate(t);            List
          
            messageList = new ArrayList<>(); for (ConstraintViolation
           
             constraintViolation : constraintViolations) { messageList.add(constraintViolation.getMessage()); } return messageList; } }
           
          
         
        
       
      
     

2.SpringMVC中的应用:

实体类的注解还是和Student类一样,只是controller接值的时候需要做点改动如下:

// 使用@Valid 表明获取到的数据模型需要验证，传入的Errors对象就是验证出错之后的数据对象，包括校验错误的个数，具体的信息等@RequestMapping(value="/register", method=RequestMethod.POST)public String registerForm(        @Valid @ModelAttribute Student stu, Errors error){    logger.info("注册新用户");        if ( error.hasErrors()) {        logger.error("出错啦");    }        stuList.add(stu);    logger.info("注册的用户信息：/n" + stu);        return "login";}