jsp自定義標籤的學習[從學習到工作(五)]
阿新 • • 發佈：2018-11-28
在現在的開發平臺上發現有自己定義的標籤，於是在空閒時間學習了一下自定義標籤，並且做了一個簡單的ajax校驗的text標籤，廢話少說，看下面的步驟和程式碼。
一. jsp頁面包含的內容
<%@taglib uri="http://com.zenglx.dream" prefix="my"%> <!--由於用到了jquery的ajax方法所以引入jquery包--> <script type="text/javascript" src="${pageContext.request.contextPath}/js/jquery.min.js"></script> <!-- validateClazz是校驗的自定義類,methdo的是定義的方法 --> 使用者名稱:<my:text id="ddddd" name="aaa" method="validate" validateClazz="com.test.tld.MyValidate"/> 使用者名稱2：<my:text validateClazz="com.test.tld.MyValidate2" name="cccc" method="validate" id="aaa"/>
二.tld檔案的編寫
<?xml version="1.0" encoding="UTF-8" ?> <taglib xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd" version="2.0"> <description>myself </description> <display-name>mytest</display-name> <tlib-version>1.0</tlib-version> <short-name>my</short-name> <uri>http://com.zenglx.dream</uri> <tag> <name>text</name> <tag-class>com.test.tld.MyText</tag-class> <body-content>empty</body-content> <attribute> <name>id</name> <required>true</required> <rtexprvalue>true</rtexprvalue> </attribute> <attribute> <name>name</name> <required>true</required> <rtexprvalue>true</rtexprvalue> </attribute> <attribute> <description>Custom method</description> <name>method</name> <required>true</required> <rtexprvalue>true</rtexprvalue> </attribute> <attribute> <description>Custom class</description> <name>validateClazz</name> <required>true</required> <rtexprvalue>true</rtexprvalue> </attribute> </tag> </taglib>
三.web.xml的配置
<jsp-config>
<taglib>
<taglib-uri>http://com.zenglx.dream</taglib-uri>
<taglib-location>/WEB-INF/tld/myTest.tld</taglib-location>
</taglib>
</jsp-config>
package com.test.tld;
import java.io.IOException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.jsp.JspContext;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.tagext.SimpleTagSupport;
public class MyText extends SimpleTagSupport {
private String id;
private String name;
private String method;
private String validateClazz;
public void setId(String id) {
this.id = id;
}
public void setName(String name) {
this.name = name;
}
public void setMethod(String method) {
this.method = method;
}
public void setValidateClazz(String validateClazz) {
this.validateClazz = validateClazz;
}
@Override
public void doTag() throws JspException, IOException {
JspContext jc = this.getJspContext();
PageContext pc = (PageContext) jc;
//String count = (String) pc.getAttribute("count");
HttpServletRequest request = ((HttpServletRequest) pc.getRequest());
//獲得專案路徑
String path = request.getContextPath();
//獲得專案在機器上的真是路徑
//String realPath = pc.getServletContext().getRealPath("/");
JspWriter jw = jc.getOut();
jw.println("<input type='text' id='" + id + "' name='" + name
+ "'/><span id='" + id + "s'></span>");
jw.println("<br/>");
jw.println("<script type='text/javascript'>");
jw.println("$(function(){" + "$('#" + id + "').focus(function(){"
+ "$('#" + id + "s').text('') " + "});" + "$('#" + id
+ "').blur(function(){" + "var value=$('#" + id + "').val();"
+ "$.ajax({" + "cache: false," + "async: true,"
+ "type:'POST'," + "data: {textData: value,validateClazz:'"
+ validateClazz + "',method:'" + method + "'}," + "url:'"
+ path + "/validateData'," + "success: function(info) {"
+ " $('#" + id + "s').css('color','red');" + " $('#" + id
+ "s').text(info);" + "}});" + "})});");
jw.println("</script>");
jw.flush();
}
}
package com.test.view;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ValidateDataServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String value = request.getParameter("textData");
String validateClazz = request.getParameter("validateClazz");
String vlidateMethod = request.getParameter("method");
try {
//反射得到位元組碼檔案
Class clazz = Class.forName(validateClazz);
//得到自定義類
Object o = clazz.newInstance();
//得到自定義方法
Method m = clazz.getMethod(vlidateMethod,String.class);
//設定私有方法許可權
m.setAccessible(true);
//執行方法獲取返回值
String info = (String) m.invoke(o, value);
//將返回值寫入頁面
response.getWriter().write(info);
}catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
} catch (SecurityException e) {
e.printStackTrace();
} catch (NoSuchMethodException e) {
e.printStackTrace();
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doGet(request, response);
}
}
package com.test.tld;
public class MyValidate {
public String validate(String value) {
//自定義的java校驗類
String info = null;
if(null!=value&&("1234").equals(value)) {
info = "恭喜你使用者名稱可用!";
} else {
info = "對不起,使用者名稱不可用";
}
return info;
}
}
package com.test.tld;
public class MyValidate2 {
public String validate(String value) {
//自定義的java校驗類
String info = null;
if(null!=value&&("1111").equals(value)) {
info = "恭喜你使用者名稱可用!";
} else {
info = "對不起,使用者名稱不可用";
}
return info;
}
}