java struts2入门学习--基于xml文件的声明式验证

一.知识点总结

后台验证有两种实现方式:

1 手工验证顺序:validateXxx(针对Action中某个业务方法验证)--> validate(针对Action中所有的业务方法验证)

2 声明式验证

　　validate()===>"Action的类名-validation.xml"===>必须放置在Action类的同目录下

validateXxx()===>"Action的类名-<action>标签中的name属性值-validation.xml"必须放置在与Action类同目录下.

当存在两种验证文件时,其结果是二者验证效果之和,针对下面的例子:先执行ValidatorAction-validation.xml,后执行ValidationAction-ValidationAction-validation.xml

二.需求

这里要求使用后台验证,而非JS实现如下需求:

1.给定一个表单如下图所示:

2.所有选项都是必填的,这里要做个验证,提示信息如下图所示:

3.并且有固定的格式,

1)用户名必须是中文!

2)密码长度应为6-20位!

3)薪水范围为4000-10000!

4)生日必须介于1970-1-1到2070-1-1之间

4.如果验证成功,那么出现如下提示页面

三.实现

需求分析:如果手动式验证,可能要写很多判断,而且实现起来可能还比较麻烦.对于上面常见的验证需求,sturts2做了很好的封装,这里就介绍关于使用声明式的验证来完成上述需求

1.实现代码

validator.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>validator</title>

</head>

<body>

    <s:form action="ValidatorAction" type="POST">

        <s:textfield label="用户名" name="username" />

        <s:password label="密码" name="password" showPassword="true"/>

        <s:textfield label="薪水" name="salary" />

        <s:textfield label="生日" name="birthday"/>

        <s:submit name="submit"/>

    </s:form>

</body>

</html>

validator_success.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>

    验证成功!<br><hr>

    用户名:<s:property value="username"/><br>

    密码:<s:property value="password"/><br>

    薪水:<s:property value="salary"/><br>

    生日:<s:property value="birthday"/><br>

</body>

</html>

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>

    <!--<include file="config/upload.xml"></include> -->

    <!-- 加载其他配置文件 -->

    <!-- <include file="config/upload-interceptor.xml"></include> -->

    <!-- 加载属性文件－国际化 -->

    <!-- <constant name="struts.custom.i18n.resources" value="message"></constant> -->    <!-- 结果集 -->

    <!-- <include file="config/result_struts.xml"></include> -->

    <!-- 类型转换 -->

    <!-- <include file="config/type_struts.xml"></include> -->

    <!-- 文件下载 -->

    <!-- <include file="config/download_struts.xml"></include> -->

    <!-- 验证validator -->

    <include file="config/validator_struts.xml"></include>

</struts>

ValidatorAction.java

package validator;

import java.util.Date;

import com.opensymphony.xwork2.ActionSupport;

/**

* @ClassName: ValidatorAction

* @Description: 验证action

* @author: amosli

* @email:amosli@infomorrow.com

* @date Feb 16, 2014 10:13:50 PM

*/

public class ValidatorAction extends ActionSupport {

    private static final long serialVersionUID = 3437178521341339431L;

    private String username;// 用户名

    private String password;// 密码

    private Double salary;// 薪水

    private Date birthday;// 生日

    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 Double getSalary() {

        return salary;

    }

    public void setSalary(Double salary) {

        this.salary = salary;

    }

    public Date getBirthday() {

        return birthday;

    }

    public void setBirthday(Date birthday) {

        this.birthday = birthday;

    }

    public String execute() throws Exception {

        return SUCCESS;

    }

}

ValidatorAction-validation.xml

<?xml version="1.0" encoding="UTF-8"?>

 <!DOCTYPE validators PUBLIC

          "-//Apache Struts//XWork Validator 1.0.3//EN"

          "http://struts.apache.org/dtds/xwork-validator-1.0.3.dtd">

<!-- 针对Action中所有的业务方法验证,类似于Validate()方法 -->

<validators>

    <!-- name表示需要验证的字段 -->

    <field name="username">

        <!-- type表示需要使用的struts2内置验证器的名字 -->

        <field-validator type="requiredstring">

            <!-- 参数trim表示去除空格 -->

            <param name="trim">true</param>

            <!-- 验证错误提示信息 -->

            <message>用户名必填!</message>

        </field-validator>

        <field-validator type="regex">

            <param name="regexExpression">[\u4E00-\uFA29]+</param>

            <message>用户名必须是中文!</message>

        </field-validator>

    </field>

    <field name="password">

        <field-validator type="requiredstring">

        <message>密码必填!</message>

        </field-validator>

        <field-validator type="regex">

            <param name="regexExpression">\w{6,20}</param>

            <message>密码长度应为6-20位!</message>

        </field-validator>

    </field>

    <field name="salary">

        <field-validator type="required">

            <param name="trim">true</param>

            <message>薪水必填!</message>

        </field-validator>

        <field-validator type="double">

            <param name="minInclusive">4000</param>

            <param name="maxInclusive">10000</param>

            <message>薪水范围为4000-10000</message>

        </field-validator>

    </field>

    <field name="birthday">

        <field-validator type="required">

            <param name="trim">true</param>

            <message>生日必填!</message>

        </field-validator>

            <field-validator type="date">

            <param name="min">1970-1-1</param>

            <param name="max">2070-1-1</param>

            <message>生日必须介于1970-1-1到2070-1-1之间</message>

        </field-validator>

    </field>

</validators>

2.代码分析

1).validator.jsp是程序入口,在其中定义了一个form表单,触发一个ValidatorAction

2).struts.xml使用include属性加载validator_struts.xml

3).validator_struts.xml,配置ValidatorAction,配置成功和出现异常的两种跳转,成功则跳转到validator_success.jsp,失败则跳回到validator.jsp

4).ValidatorAction.java,对应validator.jsp,定义username,passoword,salary,birthday,并提供set/get方法供注入和调用.

5).ValidatorAction-validation.xml,必须放在与ValidatorAction.java同一目录下,其命名规则为"xxxAction--validation.xml",这里主要调用struts2中内置的验证方法.也是本文重点.

/home/amosli/.m2/repository/org/apache/struts/xwork/xwork-core/2.3.16/xwork-core-2.3.16.jar/xwork-validator-1.0.3.dtd定义了ValidatorAction-validation.xml的格式规则.

xwork-core-2.3.16.jar/com/opensymphony/xwork2/validator/validators/default.xml,是验证器映射配置所在,也是核心配置源码所在.

<field name="xx"> ==> name表示需要验证的字段

<field-validator type="requiredstring"> ==> type表示需要使用的struts2内置验证器的名字,requiredstring和required分别表示,此项是必须是字符串类型的和此项是必须的,其中参数

<param name="trim">true</param> ==>trim表示去除首尾空格.
<message>xxx</message> ==>表示提示信息

double表示验证的类型必须的是Double型的.

<param name="minInclusive">4000</param> ===>minInclusive相当于>=,表示数值要大于等于参数值.
<param name="maxInclusive">10000</param> ===>maxInclusive相当于<=,表示数值要小于等于参数值.

还有minExclusive,maxExclusive相对应的表示>,<

date表示验证的类型将必须是Date类型的.其中参数

<param name="min">1970-1-1</param> ===> min即表示起始日期,最小日期
<param name="max">2070-1-1</param> ===>min即表示截止日期,最大日期

regex,表示可以使用正则表达式来实现,如下所示

<field-validator type="regex">
<param name="regexExpression">\w{6,20}</param> ===>regexExpression表示将要匹配的正则表达式
<message>密码长度应为6-20位!</message> ===> 自定义提示信息
</field-validator>

具体内容可以参见其源码实现,在 xwork-core-2.3.16.jar/com/opensymphony/xwork2/validator/validators/default.xml有对应的源码,ctrl+shitf+t,即可跳转到对应的源码,快速入门可以先看注释,再看其实现代码.

6)validator_success.jsp,使用struts-tags标签来调用ValidatorAction中的get方法来获取输入的值.最终显示到页面上.

3.本文源码

基于xml文件的声明式验证 https://github.com/amosli/strut2_learn