51前写的一篇跨域提交数据的blog——JQuery AJAX跨域提交参数、接收json数据，在IE中使用时，页面会弹出提示“该页正在访问其控制范围之外的信息。这可能导致安全风险。是否继续？”，虽然在chrome和firefox里面则没这个提示，但IE用户还是较多，总感觉有点用户体验上有所欠缺，今天参考IBM社区的一篇文章——使用 JSONP 实现跨域通信，改了一下代码，使用jsonp的方式来实现，修改如下：

Servlet代码：

?

public class ProvideCourseInfo extends HttpServlet{

	private static final long serialVersionUID = -487357559770822253L;
	private ICourseService courseService;

	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) 
	  throws ServletException, IOException {
		String jsonData = getDataAsJson(req.getParameter("symbol"));
		String output = req.getParameter("callback") + "(" + jsonData + ");";

        resp.setCharacterEncoding("UTF-8");
		resp.setContentType("text/javascript");
	          
		PrintWriter out = resp.getWriter();
		out.println(output);
	}
	
	private String getDataAsJson(String courseNumber) {
		if(StringUtil.isBlank(courseNumber)){
			Course course = courseService.getValidCourse(courseNumber);
			if(course!=null){
				StringBuilder sb = new StringBuilder();
				String courseName = course.getCourseName();
				sb.append("{");
				sb.append("\"");
				sb.append("courseName");
				sb.append("\"");
				sb.append(":");
				sb.append("\"");
				sb.append(courseName);
				sb.append("\"");
				Integer lang = course.getLang();
				sb.append(",");
				sb.append("\"");
				sb.append("lang");
				sb.append("\"");
				sb.append(":");
				sb.append("\"");
				sb.append(lang);
				sb.append("\"");
				sb.append("}");
				
				course = null;
				return sb.toString();
			}
		}
		return "0";
	}

	@Override
	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		this.doGet(request, response);
	}
	
	@Override
	public void init() throws ServletException {
		super.init();
		ApplicationContext context = WebApplicationContextUtils.getWebApplicationContext(this
.getServletContext());
		courseService = (ICourseService) context.getBean("courseService");
	}
}

<script type="text/javascript">
function showCourseInfo(){
		var resourceCode = document.getElementById("resourceCode").value;
	 	jQuery.getJSON("http://10.10.6.31:8099/jsonp/provideCourseInfo?symbol="+resourceCode+"&callback=?", 
		function(data) {
          if(data!="0"){
  			   document.getElementById('resourceName').value = data.courseName;
			   document.getElementById('languageType').value = data.lang;
          }else{
          	   document.getElementById('resourceName').value = '';
			   document.getElementById('languageType').value = '';
          	   alert("课件编码不存在!!!");
	      }
		});
	 }
</script>
<dt>
                        <label><span>*</span> 课件编码：</label>
                    </dt>
                    <dd>
                        <input type="text" class="default_txt" id="resourceCode" name="resourceCode" value="112290_eng"/>
                        <input name="Button2" type="button" class="btn btn_default" onclick="showCourseInfo()" value="Load…" />
                    </dd>