原創，非轉
基于JAVA標注實現統一的前臺（JS層）后臺（JAVA層）想法[/b]
通過標注的方式進行前后臺的統一驗證的好處是很多的，增強前后臺驗證的一致性，減少代碼的重復，不需要前臺與一份驗證，后臺再寫一份了。

本人想基于這種方式寫一個基于Annotation的完整的Validator的開源的小框架，但發現要做的事情很多，工作量很大，要一點一點的來，一點一點的完善，最后閑時寫了個大　概，與大家一起探討，

1. 通過JAVA標注將前臺和后臺的驗證規則標到JAVA的值對象的類中。
2. Validator在初始化的過程中，一次性讀入JAVA的值對象的類中驗證規則的標注信息，并生成前臺需要的校驗的JS文件。
3. 前臺頁面可以直接引入自動生成的校驗的JS文件，進行校驗。a
4. 后臺得到從前臺請求request綁定好值的JAVA的值對象，通過AnnotationValidator類進行驗證。

以下是Annotation標注的代碼。

進行不可以為空的校驗標注

進行是否是整數的校驗標注

用于添寫字段中文的標注



驗證器的代碼：

package com.javaest.validity.process;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import com.javaest.util.StringUtils;
import com.javaest.validity.annotation.CanNotNull;
import com.javaest.validity.annotation.FieldDesc;
import com.javaest.validity.annotation.IsInteger;
import com.javaest.validity.test.pojo.Student;
public class PojoBeanAnnotationValiditer {
private static Map<String, Map> allValidityRuleMap = new HashMap<String, Map>();
private static Map<String, Map> allFieldDescMap = new HashMap<String, Map>();
private static String jsValiditerFilePath;
private static String[] pojoBeanPackageName;
/**
*
將指定的包下邊的所有Pojo類的標注信息一次性的讀取到Map中，以備以后驗證對象時使用
*/
public static void loadAllClassAnnotationValidityInfoInPackage(String[] packageNameArr)
throws IllegalArgumentException, SecurityException, IllegalAccessException, NoSuchMethodException,
InvocationTargetException, ClassNotFoundException, IOException {
for (int i = 0; i < packageNameArr.length; i++) {
List<Class> classList = ReflectUtils.getAllClassInPackage(packageNameArr[i]);
for (int j = 0; j < classList.size(); j++) {
Class currClass = classList.get(j);
String classFullName = currClass.getPackage().getName() + "." + currClass.getName();
Map[] validityRuleMapAndFieldDescMap = loadValidityRuleAndCreateValidityJsFile(currClass);
allValidityRuleMap.put(classFullName, validityRuleMapAndFieldDescMap[0]);
allFieldDescMap.put(classFullName, validityRuleMapAndFieldDescMap[1]);
}
}
}
/*
* 對具體的一個類的標注做處理，讀入字段描述　信息，讀入非空驗證信息，讀入整數驗證信息，并根據這些信息生成JS代碼。
*/
private static Map[] loadValidityRuleAndCreateValidityJsFile(Class currClass) throws IllegalArgumentException,
IllegalAccessException, SecurityException, NoSuchMethodException, InvocationTargetException, IOException {
StringBuffer validityCanNotNullJsStrBuf = new StringBuffer();
StringBuffer validityIsIntegerJsStrBuf = new StringBuffer();
Field[] fieldArr = currClass.getDeclaredFields();
List<String> canNotNullFieldNameList = new ArrayList<String>();
List<IsIntegerValiditerRuleInfo> isIntegerValiditerRuleInfoList = new ArrayList<IsIntegerValiditerRuleInfo>();
Map<String, String> fieldDescMap = new HashMap<String, String>();
for (int i = 0; i < fieldArr.length; i++) {
String currFieldName = fieldArr[i].getName();
//讀入字段描述　信息
FieldDesc fieldDescAnnotation = fieldArr[i].getAnnotation(FieldDesc.class);
if (fieldDescAnnotation != null) {
String fieldDesc = fieldDescAnnotation.value();
System.out.println(fieldDesc);
fieldDescMap.put(currFieldName, fieldDesc);
}
else {
fieldDescMap.put(currFieldName, currFieldName);
}
//讀入非空驗證信息
if (fieldArr[i].isAnnotationPresent(CanNotNull.class)) {
canNotNullFieldNameList.add(currFieldName);
validityCanNotNullJsStrBuf.append("if(document.all." + currFieldName + ".value.trim()==\"\"){alert('"
+ fieldDescMap.get(currFieldName) + "不可以為空');}\n");
}
//讀入整數驗證信息
IsInteger isIntegerAnnotation = fieldArr[i].getAnnotation(IsInteger.class);
if (isIntegerAnnotation != null) {
int minWidth = isIntegerAnnotation.minWidth();
int maxWidth = isIntegerAnnotation.maxWidth();
int minValue = isIntegerAnnotation.minValue();
int maxValue = isIntegerAnnotation.maxValue();
IsIntegerValiditerRuleInfo isIntegerValiditerRuleInfo = new IsIntegerValiditerRuleInfo(currFieldName,
minWidth, maxWidth, minValue, maxValue);
isIntegerValiditerRuleInfoList.add(isIntegerValiditerRuleInfo);
if (minWidth > 0) {
validityIsIntegerJsStrBuf.append("if(document.all." + currFieldName
+ ".value.length()<minWidth){alert('" + fieldDescMap.get(currFieldName) + "寬度不夠！');}\n");
}
if (maxWidth < Integer.MAX_VALUE) {
validityIsIntegerJsStrBuf.append("if(document.all." + currFieldName
+ ".value.length()>maxWidth){alert('" + fieldDescMap.get(currFieldName) + "寬度太長！');}\n");
}
if (minValue > Integer.MIN_VALUE) {
validityIsIntegerJsStrBuf.append("if(document.all." + currFieldName + ".value*1<minValue){alert('"
+ fieldDescMap.get(currFieldName) + "的數值太小！');}\n");
}
if (maxValue < Integer.MAX_VALUE) {
validityIsIntegerJsStrBuf.append("if(document.all." + currFieldName + ".value*1>maxValue){alert('"
+ fieldDescMap.get(currFieldName) + "的數值太大！');}\n");
}
}
}
Map<String, List> classValidityRuleMap = new HashMap<String, List>();
classValidityRuleMap.put("canNotNullFieldNameList", canNotNullFieldNameList);
classValidityRuleMap.put("isIntegerValiditerRuleInfoList", isIntegerValiditerRuleInfoList);
//根據這些信息生成JS代碼
BufferedWriter jsFileWriter = new BufferedWriter(new FileWriter(new File(jsValiditerFilePath
+ java.io.File.separator + currClass.getName() + ".js")));
jsFileWriter.write(validityCanNotNullJsStrBuf.toString());
jsFileWriter.write(validityIsIntegerJsStrBuf.toString());
jsFileWriter.close();
return new Map[] { classValidityRuleMap, fieldDescMap };
}
/*
* 具體的后臺驗證過程
*/
public static ValidityResult validity(Object currObj) throws IllegalArgumentException, IllegalAccessException,
SecurityException, NoSuchMethodException, InvocationTargetException {
Class aClass = currObj.getClass();
String classFullName = aClass.getPackage().getName() + "." + aClass.getName();
Field[] fieldArr = aClass.getDeclaredFields();
Map validityRuleMap = allValidityRuleMap.get(classFullName);
Map fieldDescMap = allFieldDescMap.get(classFullName);
List canNotNullFieldNameList = (List) validityRuleMap.get("canNotNullFieldNameList");
List isIntegerValiditerRuleInfoList = (List) validityRuleMap.get("isIntegerValiditerRuleInfoList");
ValidityResult validityResult = new ValidityResult();
for (int j = 0; j < canNotNullFieldNameList.size(); j++) {
String currFieldName = (String) canNotNullFieldNameList.get(j);
String getMethodName = "get" + currFieldName.substring(0, 1).toUpperCase() + currFieldName.substring(1);
Method getFieldValueMethod = aClass.getMethod(getMethodName);
String fieldValue = ((String) getFieldValueMethod.invoke(currObj));
if (fieldValue == null || fieldValue.equals("")) {
System.out.println(fieldDescMap.get(currFieldName) + " 不可以為空 ! ");
validityResult.addValidityInfo(fieldDescMap.get(currFieldName) + " 不可以為空 ! ");
}
}
for (int j = 0; j < isIntegerValiditerRuleInfoList.size(); j++) {
IsIntegerValiditerRuleInfo isIntegerValiditerRuleInfo = (IsIntegerValiditerRuleInfo) isIntegerValiditerRuleInfoList
.get(j);
String currFieldName = isIntegerValiditerRuleInfo.getFieldName();
String getMethodName = "get" + currFieldName.substring(0, 1).toUpperCase() + currFieldName.substring(1);
Method getFieldValueMethod = aClass.getMethod(getMethodName);
String fieldValue = ((String) getFieldValueMethod.invoke(currObj));
int minWidth = isIntegerValiditerRuleInfo.getMinWidth();
int maxWidth = isIntegerValiditerRuleInfo.getMaxWidth();
int minValue = isIntegerValiditerRuleInfo.getMinValue();
int maxValue = isIntegerValiditerRuleInfo.getMaxValue();
if (StringUtils.isInteger(fieldValue)) {
if (fieldValue.length() < minWidth) {
validityResult.addValidityInfo(fieldDescMap.get(currFieldName) + " 寬度不可以小于 " + minWidth + "! ");
}
if (fieldValue.length() > maxWidth) {
validityResult.addValidityInfo(fieldDescMap.get(currFieldName) + " 寬度不可以大于 " + maxWidth + "! ");
}
if (Integer.parseInt(fieldValue) < minValue) {
validityResult.addValidityInfo(fieldDescMap.get(currFieldName) + " 的值不可以小于 " + minValue + "! ");
}
if (Integer.parseInt(fieldValue) > maxValue) {
validityResult.addValidityInfo(fieldDescMap.get(currFieldName) + " 的值不可以大于 " + maxValue + "! ");
}
}
else {
validityResult.addValidityInfo(fieldDescMap.get(currFieldName) + " 必須是整數格式 ! ");
}
}
return validityResult;
}
public static String[] getPojoBeanPackageName() {
return pojoBeanPackageName;
}
public static void setPojoBeanPackageName(String[] pojoBeanPackageName) {
PojoBeanAnnotationValiditer.pojoBeanPackageName = pojoBeanPackageName;
}
public static String getJsValiditerFilePath() {
return jsValiditerFilePath;
}
public static void setJsValiditerFilePath(String jsValiditerFilePath) {
PojoBeanAnnotationValiditer.jsValiditerFilePath = jsValiditerFilePath;
}
public static void main(String[] args) throws IllegalArgumentException, IllegalAccessException, SecurityException,
NoSuchMethodException, InvocationTargetException, ClassNotFoundException, IOException {
PojoBeanAnnotationValiditer.setPojoBeanPackageName(new String[] { "com.javaest.validity.test.pojo" });
PojoBeanAnnotationValiditer.setJsValiditerFilePath("JS\\VALIDITY");
PojoBeanAnnotationValiditer
.loadAllClassAnnotationValidityInfoInPackage(new String[] { "com.javaest.validity.test.pojo" });
Student aStudent = new Student();
aStudent.setAddress("吉林省長春市二道區");
aStudent.setId("");
aStudent.setAge("9");
ValidityResult validityResult = PojoBeanAnnotationValiditer.validity(aStudent);
}
}

下邊是一個加好了標注的Student類



在家閑著寫代碼真好。