第5章—构建Spring Web应用程序—关于spring中的validate注解后台校验的解析
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: <dependency> <groupId>javax.validation</groupId> <artifactId>validation-api</artifactId> <version>1.1.0.Final</version> </dependency> 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<String> 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 <T> List<String> validate(T t) { Validator validator = factory.getValidator(); Set<ConstraintViolation<T>> constraintViolations = validator.validate(t); List<String> messageList = new ArrayList<>(); for (ConstraintViolation<T> 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"; }
