Java注解Annotation用起來很方便，也越來越流行，由于其簡單、簡練且易于使用等特點，很多開發工具都提供了注解功能，不好的地方就是代碼入侵比較嚴重，所以使用的時候要有一定的選擇性。
這篇文章將利用注解，來做一個Bean的數據校驗。
下載
http://download.csdn.net/download/hanghangaidoudou/10139375
項目結構?
定義注解
該注解可以驗證成員屬性是否為空，長度，提供了幾種常見的正則匹配，也可以使用自定義的正則去判斷屬性是否合法，同時可以為該成員提供描述信息。
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 | package?org.xdemo.validation.annotation;import?java.lang.annotation.ElementType;import?java.lang.annotation.Retention;import?java.lang.annotation.RetentionPolicy;import?java.lang.annotation.Target;import?org.xdemo.validation.RegexType;/**?*?數據驗證?*?@author?Goofy?*/@Retention(RetentionPolicy.RUNTIME)@Target({ElementType.FIELD,ElementType.PARAMETER})public?@interface?DV?{?????????//是否可以為空????boolean?nullable()?default?false;?????????//最大長度????int?maxLength()?default?0;?????????//最小長度????int?minLength()?default?0;?????????//提供幾種常用的正則驗證????RegexType?regexType()?default?RegexType.NONE;?????????//自定義正則驗證????String?regexExpression()?default?"";?????????//參數或者字段描述,這樣能夠顯示友好的異常信息????String?description()?default?"";} |
注解的解析
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 | package?org.xdemo.validation.annotation.support;import?java.lang.reflect.Field;import?org.xdemo.validation.RegexType;import?org.xdemo.validation.annotation.DV;import?org.xdemo.validation.utils.RegexUtils;import?org.xdemo.validation.utils.StringUtils;/**?*?注解解析?*?@author?Goofy?*/public?class?ValidateService?{?????????private?static?DV?dv;?????????public?ValidateService()?{????????super();????}?????????//解析的入口????public?static?void?valid(Object?object)?throws?Exception{????????//獲取object的類型????????Class<??extends?Object>?clazz=object.getClass();????????//獲取該類型聲明的成員????????Field[]?fields=clazz.getDeclaredFields();????????//遍歷屬性????????for(Field?field:fields){????????????//對于private私有化的成員變量，通過setAccessible來修改器訪問權限????????????field.setAccessible(true);????????????validate(field,object);????????????//重新設置會私有權限????????????field.setAccessible(false);????????}????}??????????????public?static?void?validate(Field?field,Object?object)?throws?Exception{????????String?description;????????Object?value;????????//獲取對象的成員的注解信息????????dv=field.getAnnotation(DV.class);????????value=field.get(object);?????????????????if(dv==null)return;?????????????????description=dv.description().equals("")?field.getName():dv.description();?????????????????/*************注解解析工作開始******************/????????if(!dv.nullable()){????????????if(value==null||StringUtils.isBlank(value.toString())){????????????????throw?new?Exception(description+"不能為空");????????????}????????}?????????????????if(value.toString().length()>dv.maxLength()&&dv.maxLength()!=0){????????????throw?new?Exception(description+"長度不能超過"+dv.maxLength());????????}?????????????????if(value.toString().length()<dv.minLength()&&dv.minLength()!=0){????????????throw?new?Exception(description+"長度不能小于"+dv.minLength());????????}?????????????????if(dv.regexType()!=RegexType.NONE){????????????switch?(dv.regexType())?{????????????????case?NONE:????????????????????break;????????????????case?SPECIALCHAR:????????????????????if(RegexUtils.hasSpecialChar(value.toString())){????????????????????????throw?new?Exception(description+"不能含有特殊字符");????????????????????}????????????????????break;????????????????case?CHINESE:????????????????????if(RegexUtils.isChinese2(value.toString())){????????????????????????throw?new?Exception(description+"不能含有中文字符");????????????????????}????????????????????break;????????????????case?EMAIL:????????????????????if(!RegexUtils.isEmail(value.toString())){????????????????????????throw?new?Exception(description+"地址格式不正確");????????????????????}????????????????????break;????????????????case?IP:????????????????????if(!RegexUtils.isIp(value.toString())){????????????????????????throw?new?Exception(description+"地址格式不正確");????????????????????}????????????????????break;????????????????case?NUMBER:????????????????????if(!RegexUtils.isNumber(value.toString())){????????????????????????throw?new?Exception(description+"不是數字");????????????????????}????????????????????break;????????????????case?PHONENUMBER:????????????????????if(!RegexUtils.isPhoneNumber(value.toString())){????????????????????????throw?new?Exception(description+"不是數字");????????????????????}????????????????????break;????????????????default:????????????????????break;????????????}????????}?????????????????if(!dv.regexExpression().equals("")){????????????if(value.toString().matches(dv.regexExpression())){????????????????throw?new?Exception(description+"格式不正確");????????????}????????}????????/*************注解解析工作結束******************/????}} |
用到的幾個類
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | package?org.xdemo.validation;/**?*?常用的數據類型枚舉?*?@author?Goofy?*?*/public?enum?RegexType?{?????????NONE,????SPECIALCHAR,????CHINESE,????EMAIL,????IP,?????NUMBER,????PHONENUMBER;?????} |
其中正則驗證類和字符串工具類請參考以下鏈接：
-
SuperUtil之RegexUtils
-
SuperUtil之StringUtils
使用方法
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 | package?org.xdemo.validation.test;import?org.xdemo.validation.RegexType;import?org.xdemo.validation.annotation.DV;public?class?User?{?????????@DV(description="用戶名",minLength=6,maxLength=32,nullable=false)????private?String?userName;?????????private?String?password;?????????@DV(description="郵件地址",nullable=false,regexType=RegexType.EMAIL)????private?String?email;??????????????public?User(){}?????????public?User(String?userName,?String?password,?String?email)?{????????super();????????this.userName?=?userName;????????this.password?=?password;????????this.email?=?email;????}???????????????????public?String?getUserName()?{????????return?userName;????}????public?void?setUserName(String?userName)?{????????this.userName?=?userName;????}????public?String?getPassword()?{????????return?password;????}????public?void?setPassword(String?password)?{????????this.password?=?password;????}????public?String?getEmail()?{????????return?email;????}????public?void?setEmail(String?email)?{????????this.email?=?email;????}} |
測試代碼
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 | package?org.xdemo.validation.test;import?org.xdemo.validation.annotation.support.ValidateService;/**?*?@author?Goofy?*/public?class?Test?{????public?static?void?main(String[]?args){????????User?user=new?User("張三",?"xdemo.org",?"252878950@qq.com");????????try?{????????????ValidateService.valid(user);????????}?catch?(Exception?e)?{????????????e.printStackTrace();????????}????????user=new?User("zhangsan","xdemo.org","xxx@");????????try?{????????????ValidateService.valid(user);????????}?catch?(Exception?e)?{????????????e.printStackTrace();????????}????????user=new?User("zhangsan","xdemo.org","");????????try?{????????????ValidateService.valid(user);????????}?catch?(Exception?e)?{????????????e.printStackTrace();????????}????}} |
運行效果
