我正在使用 Java 学习 RESTful Web 服务。 我的环境使用 Netbean 和 GlassFish v3。
我有一个页面 URL /inventoryList，该 URL 映射到 web.xml 中的 InventoryApp.java servlet
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app 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-app_2_4.xsd"
version="2.4">
<servlet>
<servlet-name>inventory servlet</servlet-name>
<servlet-class>local.test.servlet.InventoryApp</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>inventory servlet</servlet-name>
<url-pattern>/inventoryList</url-pattern>
</servlet-mapping>
</web-app>
在servlet中，它从DB中获取库存商品信息列表并显示到JSP页面。
inventory.jsp
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<%@ taglib prefix="c" uri="http://java.sun.com/jstl/core_rt" %>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
<script type="text/javascript">
function ajaxGet(inventoryId) {
alert(inventoryId);
var xmlHttp = new XMLHttpRequest();
xmlHttp.onreadystatechange = function() {
alert('sigh');
if(xmlHttp.readyState == 4 && xmlHttp.status == 200) {
alert('ready 4');
alert('After ready4 ===> ' + xmlHttp.responseText);
displayInventoryHtml(xmlHttp);
}
}
var url = "resources/inventory/" + inventoryId;
xmlHttp.open("GET", url, true);
xmlHttp.send(null);
}
function displayInventoryHtml(responseAjax) {
document.getElementById('inventoryItem').innerHTML = responseAjax.responseText;
}
</script>
</head>
<body>
<h1>Inventory page</h1>
<table border="1" cellspacing="1" cellpadding="5">
<th>id</th>
<th>amount</th>
<c:forEach items="${inventoryList}" var="inv" >
<tr>
<td>${inv.id}</td>
<td><a href="" onclick="ajaxGet(${inv.id})">${inv.amount}</a></td>
</tr>
</c:forEach>
</table>
<hr />
<div id="inventoryItem">
</div>
</body>
</html>
如您所见，inventory.jsp 将成功输出库存项目列表。
到目前为止一切顺利。
这里，我将库存金额值的输出作为 Ajax 调用的链接。
<td><a href="" onclick="ajaxGet(${inv.id})">${inv.amount}</a></td>
它调用HTTP GET方法和REST服务(代码如下所示)将获取指定id(数据库主id)的库存数据，我将Ajax响应文本放入div (id=inventoryItem)
InventoryResource.java
package local.test.jaxrs;
import java.util.List;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.UriInfo;
import javax.ws.rs.Consumes;
import javax.ws.rs.DELETE;
import javax.ws.rs.PUT;
import javax.ws.rs.Path;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import local.test.dao.InventoryDao;
import local.test.session.Inventory;
@Path("/inventory")
public class InventoryResource {
@Context
private UriInfo context;
/** Creates a new instance of InventoryResource */
public InventoryResource() {
}
@Path("{inv_id}")
@GET
@Produces("text/html")
public String getJson(@PathParam("inv_id") String inventory_id) {
System.out.println("GET is being handled");
Inventory invBean = new Inventory(Integer.valueOf(inventory_id));
InventoryDao invDao = new InventoryDao();
List<Inventory> inv = invDao.findById(invBean);
String html = "<b>" + inv.get(0).getId() + "</b><br /><b>" + inv.get(0).getAmount() + "</b><br />";
return html;
}
}//end class
当我测试这段代码时，一切正常。 Ajax成功获取数据并插入到HTML DIV标签中，库存数据显示半秒后消失。
使用firebug并查看glassfish v3服务器日志，我认为最后，它再次调用InventoryApp.java servlet，这导致页面重定向到/inventoryList
我知道 Ajax 是部分请求，不应导致页面刷新。
我已经在这几天了，有人能给我提示发生了什么事吗？ 我不确定像我一样将 servlet 和 web.xml 与 REST 混合起来是否可行。
仅供引用，我的InventoryApp.java servlet 代码
package local.test.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import local.test.dao.InventoryDao;
import local.test.session.Inventory;
@WebServlet(name="InventoryApp", urlPatterns={"/InventoryApp"})
public class InventoryApp extends HttpServlet {
/**
* Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods.
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
try {
} finally {
out.close();
}
}
// <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
/**
* Handles the HTTP <code>GET</code> method.
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
InventoryDao invDao = new InventoryDao();
List<Inventory> invList = invDao.findAll();
//this list looks ok...
System.out.println("================= do get servelt ===" + invList.get(0));
request.setAttribute("inventoryList", invList);
request.getRequestDispatcher("inventory.jsp").forward(request, response);
//processRequest(request, response); //commented not sure what it is..
}
}//end class
最佳答案
<a href="" onclick="ajaxGet(${inv.id})">${inv.amount}</a>
删除href属性
<a onclick="ajaxGet(${inv.id})">${inv.amount}</a>
或者取消点击事件的推广
<a href="" onclick="ajaxGet(${inv.id}); return false;">${inv.amount}</a>
关于java - 为什么我的Ajax调用刷新页面？ (即再次调用servlet)，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/4476212/