一個健壯的WEB應用程序必須確保用戶的輸入是合法有效的；Struts2即提供了一些基于XWork Validation Framework的內建驗證程序，使得輸入驗證不需要編程，直接在xml配置文件中聲明（待驗證字段、驗證規(guī)則、驗證出錯消息）即可。 Struts2提供聲明式驗證和編程式驗證兩種方式，常采用聲明式驗證程序，其主要需要聲明如下內容：
對哪個Action類或Model類對象的哪個字段進行驗證；采用哪種驗證規(guī)則進行驗證；若驗證失敗，則轉向何處、顯示什么錯誤信息。聲明式驗證程序分為字段驗證和非字段驗證兩類，字段驗證主要判斷某字段屬性的輸入是否有效，而非字段驗證主要是針對多個字段輸入值之間的邏輯關系進行校驗，如密碼再次輸入確認。
（1）基于字段的聲明式驗證程序的具體實現步驟
確定驗證字段：確定哪個Action類或Model類對象的哪個字段需要驗證；編寫驗證程序配置文件：若一個Action類的多個action請求使用相同的驗證規(guī)則，則其文件名為ActionClassName-validation.xml，而不同則為ActionClassName-User_create-validation.xml確定驗證失敗時的響應頁面：在struts.xml文件中定義<result name=“input”> 元素，用于指定轉向頁面。（2）編寫驗證程序配置文件
將struts-2.3.15.3/apps/struts2-blank/WEB-INF/classes/example下的Login-validation.xml文件復制到當前Action類文件所在路徑下；修改配置文件名為ActionClassName-validation.xml；編寫驗證規(guī)則: 參見struts-2.3.15.3/docs/WW/docs/validation.html文檔即可。<!--驗證程序配置文件核心內容：--><field name="age"> <field-validator type="int"> <param name="min">20</param> <param name="max">50</param> <!--注意：驗證程序錯誤消息可以進行國際化--> <message>Age needs to be between ${min} and ${max}.</message> </field-validator></field>（3）顯示驗證程序錯誤消息
<!-- 非simple主題自動顯示錯誤消息 --><s:form action="testValidation"> <s:textfield name="age" label="Age"></s:textfield> <s:submit></s:submit></s:form><br><hr><br><!-- simple主題需要使用s:fielderror標簽或EL貨OGNL表達式來顯示錯誤消息 --><s:form action="testValidation2" theme="simple"> Age: <s:textfield name="age" label="Age"></s:textfield> <br> ${fieldErrors.age[0] } <br> <s:fielderror name="age"></s:fielderror> <s:submit></s:submit></s:form>
注意：若類型轉換失敗，默認情況下仍會執(zhí)行后續(xù)的輸入驗證攔截器。可通過修改ConversionErrorInterceptor源代碼的方式使 類型轉換失敗時，直接返回input的result，即不再執(zhí)行后續(xù)的驗證攔截器。
// 創(chuàng)建相同的包 -> 新建相同的類 -> 復制源代碼 -> 修改即可Object action = invocation.getAction(); if (action instanceof ValidationAware) { ValidationAware va = (ValidationAware) action; if(va.hasFieldErrors() || va.hasActionErrors()) { return "input"; } } 非字段驗證不是針對單一字段的驗證，可以通過<s:actionerror/>標簽顯示錯誤消息；非字段驗證的配置實例如下：
問題：多個字段使用同樣的驗證規(guī)則，可否使用同一條驗證消息 ？ 解決：利用國際化資源配置文件和fieldName特殊屬性結合來實現，英文資源文件內容如下所示：
error.int=${getText(fieldName)} needs to be between ${min} and ${max}age=Agecount=Count具體代碼見附錄所示。
Struts2提供Validateable接口，可以使Action類實現該接口以提供編程驗證功能，常選擇繼承于實現了Validateable 接口的ActionSupport 類。
@Overridepublic void validate() { if(name == null || name.trim().equals("")) { addFieldError("name", getText("name.null")); }}
IDCard.java：
package com.qiaobc.struts.action;public class IDCard { final int[] wi = { 7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2, 1 }; final int[] vi = { 1, 0, 'X', 9, 8, 7, 6, 5, 4, 3, 2 }; private int[] ai = new int[18]; public IDCard() {} public boolean Verify(String idcard) { if (idcard.length() == 15) { idcard = uptoeighteen(idcard); } if (idcard.length() != 18) { return false; } String verify = idcard.substring(17, 18); if (verify.equals(getVerify(idcard))) { return true; } return false; } public String getVerify(String eightcardid) { int remaining = 0; if (eightcardid.length() == 18) { eightcardid = eightcardid.substring(0, 17); } if (eightcardid.length() == 17) { int sum = 0; for (int i = 0; i < 17; i++) { String k = eightcardid.substring(i, i + 1); ai[i] = Integer.parseInt(k); } for (int i = 0; i < 17; i++) { sum = sum + wi[i] * ai[i]; } remaining = sum % 11; } return remaining == 2 ? "X" : String.valueOf(vi[remaining]); } public String uptoeighteen(String fifteencardid) { String eightcardid = fifteencardid.substring(0, 6); eightcardid = eightcardid + "19"; eightcardid = eightcardid + fifteencardid.substring(6, 15); eightcardid = eightcardid + getVerify(eightcardid); return eightcardid; } public static void main(String[] args) { String idcard1 = "350211197607142059"; String idcard2 = "350211197607442059"; IDCard idcard = new IDCard(); System.out.println(idcard.Verify(idcard1)); System.out.println(idcard.Verify(idcard2)); }}IDCardValidator.java：
package com.qiaobc.struts.action;import com.opensymphony.xwork2.validator.ValidationException;import com.opensymphony.xwork2.validator.validators.FieldValidatorSupport;public class IDCardValidator extends FieldValidatorSupport { @Override public void validate(Object object) throws ValidationException { // 1. 獲取字段名和字段值 String fieldName = getFieldName(); Object value = this.getFieldValue(fieldName, object); // 2. 驗證 IDCard idCard = new IDCard(); boolean result = idCard.Verify((String) value); // 3. 驗證失敗轉向 if(!result) { addFieldError(fieldName, object); } }}TestValidationAction.java：
package com.qiaobc.struts.action;import com.opensymphony.xwork2.ActionSupport;public class TestValidationAction extends ActionSupport { private static final long serialVersionUID = 1L; private Integer age; private String password1; private String password2; private String idcard; public String getPassword1() { return password1; } public String getIdcard() { return idcard; } public void setIdcard(String idcard) { this.idcard = idcard; } public void setPassword1(String password1) { this.password1 = password1; } public String getPassword2() { return password2; } public void setPassword2(String password2) { this.password2 = password2; } public Integer getAge() { return age; } public void setAge(Integer age) { this.age = age; } @Override public String execute() throws Exception { System.out.println("age:" + age); System.out.println("password1:" + password1); System.out.println("password2:" + password2); return SUCCESS; }}TestValidationAction-testValidation-validation.xml：
<!DOCTYPE validators PUBLIC "-//Apache Struts//XWork Validator 1.0.2//EN" "http://struts.apache.org/dtds/xwork-validator-1.0.2.dtd"><validators> <field name="age"> <field-validator type="int"> <param name="min">20</param> <param name="max">50</param> <message>Age needs to be between ${min} and ${max}.</message> </field-validator> <field-validator type="conversion"> <message>Conversion Error Occurred.</message> </field-validator> </field> <field name="idcard"> <field-validator type="idcard"> <message>It's not a ID Card!</message> </field-validator> </field> <validator type="expression"> <param name="expression"><![CDATA[password1==password2]]></param> <message>password1 != password2</message> </validator></validators>TestValidationAction-testValidation2-validation.xml：
<!DOCTYPE validators PUBLIC "-//Apache Struts//XWork Validator 1.0.2//EN" "http://struts.apache.org/dtds/xwork-validator-1.0.2.dtd"><validators> <field name="age"> <!-- 設置短路驗證：若當前驗證沒有通過，則不再進行下面的驗證 --> <field-validator type="conversion" short-circuit="true"> <message>Conversion Error Occurred.</message> </field-validator> <field-validator type="int"> <param name="min">0</param> <param name="max">100</param> <message>Age needs to be between ${min} and ${max}.</message> </field-validator> </field></validators>struts.xml：
<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN" "http://struts.apache.org/dtds/struts-2.3.dtd"><struts> <!-- 配置全局范圍內的國際化資源文件 --> <constant name="struts.custom.i18n.resources" value="i18n"></constant> <package name="validation" namespace="/" extends="struts-default"> <action name="testValidation" class="com.qiaobc.struts.action.TestValidationAction"> <result>/success.jsp</result> <!-- 配置輸入驗證失敗時的轉向頁面 --> <result name="input">/validation.jsp</result> </action> <action name="testValidation2" class="com.qiaobc.struts.action.TestValidationAction"> <result>/success.jsp</result> <!-- 配置輸入驗證失敗時的轉向頁面 --> <result name="input">/validation.jsp</result> </action> </package></struts>validators.xml：
<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE validators PUBLIC "-//Apache Struts//XWork Validator Definition 1.0//EN" "http://struts.apache.org/dtds/xwork-validator-definition-1.0.dtd"><validators> <!-- 配置自定義攔截器 --> <validator name="idcard" class="com.qiaobc.struts.action.IDCardValidator"/></validators>validation.jsp：
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><%@ taglib uri="/struts-tags" prefix="s" %><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Insert title here</title></head><body> <s:debug></s:debug> <!-- 非simple主題自動顯示錯誤消息 --> <s:form action="testValidation"> <s:textfield name="age" label="Age"></s:textfield> <s:password name="password1" label="password1"></s:password> <s:password name="password2" label="password2"></s:password> <s:actionerror/> <s:textfield name="idcard" label="IDCard"></s:textfield> <s:submit></s:submit> </s:form></body></html>validation2.jsp：
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><%@ taglib uri="/struts-tags" prefix="s" %><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Insert title here</title></head><body> <s:debug></s:debug> <!-- simple主題需要使用s:fielderror標簽或EL貨OGNL表達式來顯示錯誤消息 --> <s:form action="testValidation2" theme="simple"> Age: <s:textfield name="age" label="Age"></s:textfield> <br><br> <s:fielderror name="age"></s:fielderror> <s:submit></s:submit> </s:form></body></html>ConversionErrorInterceptor.java：
package com.opensymphony.xwork2.interceptor;import com.opensymphony.xwork2.ActionContext;import com.opensymphony.xwork2.ActionInvocation;import com.opensymphony.xwork2.ValidationAware;import com.opensymphony.xwork2.conversion.impl.XWorkConverter;import com.opensymphony.xwork2.util.ValueStack;import org.apache.commons.lang3.StringEscapeUtils;import java.util.HashMap;import java.util.Map;public class ConversionErrorInterceptor extends AbstractInterceptor { public static final String ORIGINAL_PROPERTY_OVERRIDE = "original.property.override"; protected Object getOverrideExpr(ActionInvocation invocation, Object value) { return escape(value); } protected String escape(Object value) { return "/"" + StringEscapeUtils.escapeJava(String.valueOf(value)) + "/""; } @Override public String intercept(ActionInvocation invocation) throws Exception { ActionContext invocationContext = invocation.getInvocationContext(); Map<String, Object> conversionErrors = invocationContext.getConversionErrors(); ValueStack stack = invocationContext.getValueStack(); HashMap<Object, Object> fakie = null; for (Map.Entry<String, Object> entry : conversionErrors.entrySet()) { String propertyName = entry.getKey(); Object value = entry.getValue(); if (shouldAddError(propertyName, value)) { String message = XWorkConverter.getConversionErrorMessage(propertyName, stack); Object action = invocation.getAction(); if (action instanceof ValidationAware) { ValidationAware va = (ValidationAware) action; va.addFieldError(propertyName, message); } if (fakie == null) { fakie = new HashMap<Object, Object>(); } fakie.put(propertyName, getOverrideExpr(invocation, value)); } } if (fakie != null) { // if there were some errors, put the original (fake) values in place right before the result stack.getContext().put(ORIGINAL_PROPERTY_OVERRIDE, fakie); invocation.addPreResultListener(new PreResultListener() { public void beforeResult(ActionInvocation invocation, String resultCode) { Map<Object, Object> fakie = (Map<Object, Object>) invocation.getInvocationContext().get(ORIGINAL_PROPERTY_OVERRIDE); if (fakie != null) { invocation.getStack().setExprOverrides(fakie); } } }); } // 核心代碼 Object action = invocation.getAction(); if (action instanceof ValidationAware) { ValidationAware va = (ValidationAware) action; if(va.hasFieldErrors() || va.hasActionErrors()) { return "input"; } } return invocation.invoke(); } protected boolean shouldAddError(String propertyName, Object value) { return true; }}新聞熱點
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