按上回继续，前面写过一篇Spring MVC下的异常处理、及Spring MVC下的ajax异常处理，今天看下换成velocity模板引擎后，如何处理异常页面:
一、404错误、500错误
1 <error-page> 2 <error-code>404</error-code> 3 <location>/nopage.do</location> 4 </error-page> 5 6 <error-page> 7 <error-code>500</error-code> 8 <location>/error.do</location> 9 </error-page>
web.xml中添加这二项，注意locatoion节点，不再是指定成物理文件路径，而是Spring MVC中Controller里具体方法映射的URI
1 @RequestMapping(value = "/nopage.do", method = RequestMethod.GET)
2 public String pageNotFound(Locale locale, Model model) throws Exception {
3 return "errors/404";
4 }
5
6 @RequestMapping(value = "/error.do", method = RequestMethod.GET)
7 public String innerError(Locale locale, Model model) throws Exception {
8 return "errors/500";
9 }
上面是Controller的处理
二、常规异常的处理
Controller里的处理还是跟以前一样，关键是errors/error.vm这个模板文件如何写：
1 <!doctype html>
2 <html>
3 <head>
4 #parse("comm/header.vm")
5 #set($ex=$request.getAttribute("ex"))
6 <title>ERROR</title>
7 </head>
8 <body style="margin:20px">
9 <H2>
10 错误：$ex.class.simpleName
11 </H2>
12 <hr/>
13 <P>
14 <strong>错误描述：</strong>$ex.message
15 </P>
16
17 <P>
18 <strong>详细信息：</strong>
19 </P>
20 <pre>
21 #foreach($stack in $ex.getStackTrace())
22 $stack.toString()
23 #end
24 </pre>
25 </body>
26 </html>
注意：5、10、21-23这几行
三、ajax异常的处理
这里要在BaseController里直接返回json字符串，参考下面的代码：
1 @ExceptionHandler
2 public String exp(HttpServletRequest request, HttpServletResponse response, Exception ex) throws Exception {
3 String resultViewName = "errors/error";
4
5 // 记录日志
6 logger.error(ex.getMessage(), ex);
7
8 // 根据不同错误转向不同页面
9 if (ex instanceof BusinessException) {
10 resultViewName = "errors/biz-error";
11 } else {
12 // 异常转换
13 //ex = new Exception("服务器忙，请稍候重试！");
14 }
15
16 String xRequestedWith = request.getHeader("X-Requested-With");
17 if (!StringUtils.isEmpty(xRequestedWith)) {
18 // ajax请求
19 ResponseUtil.OutputJson(response, "{\"error\":\"" + ex.getClass().getSimpleName() + "\",\"detail\":\"" + ex.getMessage() + "\"}");
20 }
21 request.setAttribute("ex", ex);
22 return resultViewName;
23 }
关键点有2个，方法签名里增加HttpServletResponse response，然后19行，直接输出Json字符串，其中用到了一个ResponseUtil类，该类的主要代码如下：
1 public static void OutputContent(HttpServletResponse response,
2 String contentType, String content) throws IOException {
3 response.setContentType(contentType + ";charset=utf-8");
4 response.setCharacterEncoding("UTF-8");
5 PrintWriter out = response.getWriter();
6 out.println(content);
7 out.flush();
8 out.close();
9 }
10
11 public static void OutputJson(HttpServletResponse response, String content)
12 throws IOException {
13 OutputContent(response, "application/json", content);
14 }
时间： 2024-08-04 23:08:43