JSF自定義驗證器類 - tw511教學網

我們可以在JSF中建立自己的自定義驗證器。以下列表是在JSF中建立自定義驗證器的步驟。

通過實現javax.faces.validator.Validator介面建立一個驗證器類。
實現上面介面的validate()方法。
使用注釋@FacesValidator為自定義驗證器分配唯一的ID。

自定義驗證器類範例

開啟 NetBeans IDE 建立一個Web工程：CustomValidator，其目錄結構如下所示 -

建立以下檔案程式碼，檔案：index.xhtml 的程式碼內容如下所示 -

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"   
      xmlns:h="http://java.sun.com/jsf/html"
      xmlns:f="http://java.sun.com/jsf/core">
    <h:body>
        <h:form>
            <h:panelGrid columns="3">
                Enter your email :
                <h:inputText id="email" value="#{user.email}" 
                             size="20" required="true" label="Email Address">
                    <f:validator validatorId="com.yiibai.EmailValidator" />
                </h:inputText>
                <h:message for="email" style="color:red" />
            </h:panelGrid>
            <h:commandButton value="Submit" action="result" />
        </h:form>
    </h:body>
</html>

檔案：result.xhtml 的程式碼內容如下所示 -

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"   
      xmlns:h="http://java.sun.com/jsf/html"
      >
    <h:body>

        <h1>Custom validator in JSF 2.0</h1>

        <h:panelGrid columns="2">

            Email Address :  
            <h:outputText value="#{user.email}" />

        </h:panelGrid>

    </h:body>
</html>

檔案：EmailValidator.java 的程式碼內容如下所示 -

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package com.yiibai;

/**
 *
 * @author Administrator
 */
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.faces.application.FacesMessage;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.validator.FacesValidator;
import javax.faces.validator.Validator;
import javax.faces.validator.ValidatorException;

@FacesValidator("com.yiibai.EmailValidator")
public class EmailValidator implements Validator {

    private static final String EMAIL_PATTERN = "^[_A-Za-z0-9-]+(\\."
            + "[_A-Za-z0-9-]+)*@[A-Za-z0-9]+(\\.[A-Za-z0-9]+)*"
            + "(\\.[A-Za-z]{2,})$";

    private Pattern pattern;
    private Matcher matcher;

    public EmailValidator() {
        pattern = Pattern.compile(EMAIL_PATTERN);
    }

    @Override
    public void validate(FacesContext context, UIComponent component,
            Object value) throws ValidatorException {

        matcher = pattern.matcher(value.toString());
        if (!matcher.matches()) {

            FacesMessage msg
                    = new FacesMessage("E-mail validation failed.",
                            "Invalid E-mail format.");
            msg.setSeverity(FacesMessage.SEVERITY_ERROR);
            throw new ValidatorException(msg);

        }

    }

}

檔案：User.java 的程式碼內容如下所示 -

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package com.yiibai;

/**
 *
 * @author Maxsu
 */
import java.io.Serializable;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;

@ManagedBean(name = "user")
@SessionScoped
public class User implements Serializable {

    private static final long serialVersionUID = 1L;

    String email;

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

}

右鍵執行工程：CustomValidator，如果沒有任何錯誤，開啟瀏覽器存取：

http://localhost:8084/CustomValidator/

應該會看到以下結果 -

簡單寫入一些資訊(輸入一個無效的Email地址)，然後提交 -