不管是html页面表单提交的对象数据还是和第三方公司进行接口对接，都需要对接收到的数据进行校验（非空、长度、格式等等）。如果使用if一个个进行校验（字段非常多），这是让人崩溃的过程。幸好jdk或hibernate都提供了对object对象的校验，只需加上相应的注解即可。

1.项目建立

 pom.xml

[html] view plain copy
         
      
       4.0.0
          
      
       com.fei
          
      
       validation-test
          
      
       0.0.1-SNAPSHOT
              
                
                 
        
         javax.el
                  
        
         javax.el-api
                  
        
         2.2.4
              
                 
                 
        
         org.hibernate
                  
        
         hibernate-validator
                  
        
         5.1.3.Final
              
               
            
     2.基本校验练习StudentInfo.java[java] view plain copypackage com.fei.info;    import javax.validation.constraints.Pattern;    import org.hibernate.validator.constraints.NotBlank;    public class StudentInfo {        @NotBlank(message="用户名不能为空")      private String userName;            @NotBlank(message="年龄不能为空")      @Pattern(regexp="^[0-9]{1,2}$",message="年龄是整数")      private String age;            /**      * 如果是空，则不校验，如果不为空，则校验      */      @Pattern(regexp="^[0-9]{4}-[0-9]{2}-[0-9]{2}$",message="出生日期格式不正确")      private String birthday;            @NotBlank(message="学校不能为空")      private String school;        public String getUserName() {          return userName;      }        public void setUserName(String userName) {          this.userName = userName;      }        public String getAge() {          return age;      }        public void setAge(String age) {          this.age = age;      }        public String getBirthday() {          return birthday;      }        public void setBirthday(String birthday) {          this.birthday = birthday;      }        public String getSchool() {          return school;      }        public void setSchool(String school) {          this.school = school;      }  }  ValidatorUtil.java[java] view plain copypackage com.fei.util;    import java.util.HashMap;  import java.util.Map;  import java.util.Set;    import javax.validation.ConstraintViolation;  import javax.validation.Validation;  import javax.validation.Validator;  import javax.validation.groups.Default;    public class ValidatorUtil {      private static Validator validator = Validation.buildDefaultValidatorFactory()              .getValidator();            public static 
     
       Map
      
        validate(T obj){          Map
       
         errorMap = null;          Set
        
         
          > set = validator.validate(obj,Default.class);          if(set != null && set.size() >0 ){              errorMap = new HashMap
          
           (); String property = null; for(ConstraintViolation
           
             cv : set){ //这里循环获取错误信息，可以自定义格式 property = cv.getPropertyPath().toString(); if(errorMap.get(property) != null){ errorMap.get(property).append("," + cv.getMessage()); }else{ StringBuffer sb = new StringBuffer(); sb.append(cv.getMessage()); errorMap.put(property, sb); } } } return errorMap; } } ValidatorTest.java[java] view plain copypackage com.fei; import java.util.Map; import com.fei.info.StudentInfo; import com.fei.util.ValidatorUtil; public class ValidatorTest { public static void main(String[] args) { StudentInfo s = new StudentInfo(); long startTime = System.currentTimeMillis(); print(ValidatorUtil.validate(s)); System.out.println("===============耗时(毫秒)=" + (System.currentTimeMillis() - startTime)); s.setUserName("小明"); s.setAge("a10"); s.setBirthday("2016-9-1"); startTime = System.currentTimeMillis(); print(ValidatorUtil.validate(s)); System.out.println("===============耗时(毫秒)=" + (System.currentTimeMillis() - startTime)); } private static void print(Map
            
              errorMap){ if(errorMap != null){ for(Map.Entry
             
               m : errorMap.entrySet()){ System.out.println(m.getKey() + ":" + m.getValue().toString()); } } } } 来看看运行结果：[plain] view plain copy十二月 12, 2016 4:02:00 下午 org.hibernate.validator.internal.util.Version 
              
                INFO: HV000001: Hibernate Validator 5.1.3.Final school:学校不能为空 age:年龄不能为空 userName:用户名不能为空 ===============耗时(毫秒)=280 birthday:出生日期格式不正确 school:学校不能为空 age:年龄是整数 ===============耗时(毫秒)=3