使用servlet结合ajax验证数据库

1. package org.ml.drp.servlet;  

2. import java.io.IOException;  

3. import javax.servlet.ServletException;  

4. import javax.servlet.http.HttpServlet;  

5. import javax.servlet.http.HttpServletRequest;  

6. import javax.servlet.http.HttpServletResponse;  

7. import org.ml.drp.basedata.manager.ItemFactory;  

8. publicclass ItemValidate extends HttpServlet {  

9. privatestaticfinallong serialVersionUID = 1L;  

10. public ItemValidate() {  

11. super();  

12.     }  

13. publicvoid destroy() {  

14. super.destroy();    

15.     }  

16. publicvoid doGet(HttpServletRequest request, HttpServletResponse response)  

17. throws ServletException, IOException {   

18. this.doPost(request, response);  

19.     }  

20. publicvoid doPost(HttpServletRequest request, HttpServletResponse response)  

21. throws ServletException, IOException {  

22.         String itemNo = request.getParameter("itemNo");//取得物料代码

23. if(ItemFactory.getInstance().getItemManager().findItemById(itemNo)!=null){ //查询数据库

24.             response.getWriter().print("<font color=\"red\">代码已存在</font>");  

25.         }else{  

26.             response.getWriter().print("<font color=\"green\">OK!</font>");  

27.         }  

28.     }  

29. publicvoid init() throws ServletException {   

30.     }  

31. }  

package org.ml.drp.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.ml.drp.basedata.manager.ItemFactory;

public class ItemValidate extends HttpServlet {
 
	private static final long serialVersionUID = 1L;
 
	public ItemValidate() {
		super();
	}
 
	public void destroy() {
		super.destroy();  
	}
 
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException { 
		this.doPost(request, response);
	}
 
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		String itemNo = request.getParameter("itemNo");//取得物料代码
		if(ItemFactory.getInstance().getItemManager().findItemById(itemNo)!=null){ //查询数据库
			response.getWriter().print("<font color=\"red\">代码已存在</font>");
		}else{
			response.getWriter().print("<font color=\"green\">OK!</font>");
		}
	}
 
	public void init() throws ServletException { 
	}
}

配置servlet的代码：web.xml

[html]view plaincopyprint?

1. <servlet>

2. <servlet-name>ItemValidate</servlet-name>

3. <servlet-class>org.ml.drp.servlet.ItemValidate</servlet-class>

4. </servlet>

5. <servlet-mapping>

6. <servlet-name>ItemValidate</servlet-name>

7. <url-pattern>/item_validate</url-pattern>

8. </servlet-mapping>

   <servlet> 
    <servlet-name>ItemValidate</servlet-name>
    <servlet-class>org.ml.drp.servlet.ItemValidate</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>ItemValidate</servlet-name>
    <url-pattern>/item_validate</url-pattern>
  </servlet-mapping>

页面中的ajax验证代码：

[javascript]view plaincopyprint?

1.         <script type="text/javascript">  

2. var xmlHttp   

3. function createXMLHttpRequest(){  

4. if(window.XMLHttpRequest){  

5.             xmlHttp = new XMLHttpRequest();  

6.         }elseif(window.ActiveXObject){   

7.             xmlHttp = new window.ActiveXObject("Microsoft.XMLHTTP");  

8.         }  

9.     }  

10. function checkItemNo(itemNo){  

11. if(trim(itemNo.value)!=""){  

12.             createXMLHttpRequest();//创建Ajax核心对象XMLHttpRequest

13. var url = "../item_validate?itemNo="+trim(itemNo.value) + "&time="+new Date().getTime();  

14. //设置请求方式为get，设置 url请求，设置为异步提交 

15.             xmlHttp.open("get",url,true);  

16. //将方法地址赋值给属性 

17.             xmlHttp.onreadystatechange=function(){//使用匿名对象进行 

18. if(xmlHttp.readyState==4){//响应完成 

19. if(xmlHttp.status==200){//请求成功 

20. var itemNoSpan = document.getElementById("itemNoSpan");   

21.                         itemNoSpan.innerHTML=xmlHttp.responseText;  

22.                     }else{  

23.                         alert("物料代码验证请求失败，请联系管理员")     

24.                     }  

25.                 }  

26.             };  

27. //将设置的信息发送给Ajax引擎 

28.             xmlHttp.send(null);   

29.         }else{   

30.             document.getElementById("itemNoSpan").innerHTML="<font color='red'>物料代码不能为空</font>";   

31.         }   

32.     }    

33. </script>  

         <script type="text/javascript">
		var xmlHttp 
		function createXMLHttpRequest(){
			if(window.XMLHttpRequest){
				xmlHttp = new XMLHttpRequest();
			}else if(window.ActiveXObject){ 
				xmlHttp = new window.ActiveXObject("Microsoft.XMLHTTP");
			}
		}
		function checkItemNo(itemNo){
			if(trim(itemNo.value)!=""){
				createXMLHttpRequest();//创建Ajax核心对象XMLHttpRequest
				var url = "../item_validate?itemNo="+trim(itemNo.value) + "&time="+new Date().getTime();
				//设置请求方式为get，设置 url请求，设置为异步提交 
				xmlHttp.open("get",url,true);
				//将方法地址赋值给属性 
				xmlHttp.onreadystatechange=function(){//使用匿名对象进行 
					if(xmlHttp.readyState==4){//响应完成 
						if(xmlHttp.status==200){//请求成功 
							var itemNoSpan = document.getElementById("itemNoSpan"); 
							itemNoSpan.innerHTML=xmlHttp.responseText;
						}else{
							alert("物料代码验证请求失败，请联系管理员")   
						}
					}
				};
				//将设置的信息发送给Ajax引擎 
				xmlHttp.send(null); 
			}else{ 
				document.getElementById("itemNoSpan").innerHTML="<font color='red'>物料代码不能为空</font>"; 
			} 
		}  
	</script>

对应的需要验证的标签代码：

[html]view plaincopyprint?

1. <td>

2. <inputname="itemNo"type="text"class="text1"id="itemNo"size="10"maxlength="10"onblur="checkItemNo(this)"onclick="document.getElementById('itemNoSpan').innerHTML=''; ">

3. <spanid="itemNoSpan"></span>

4. </td>