使用HttpServletRequestWrapper重写Request请求参数

 1 public class ChangeRequestWrapper extends HttpServletRequestWrapper {
 2     private Map<String, String[]> parameterMap; // 所有参数的Map集合
 3 
 4     public ChangeRequestWrapper(HttpServletRequest request) {
 5         super(request);
 6         parameterMap = request.getParameterMap();
 7     }
 8 
 9     // 重写几个HttpServletRequestWrapper中的方法
10 
11     /**
12      * 获取所有参数名
13      *
14      * @return 返回所有参数名
15      */
16     @Override
17     public Enumeration<String> getParameterNames() {
18         Vector<String> vector = new Vector<String>(parameterMap.keySet());
19         return vector.elements();
20     }
21 
22     /**
23      * 获取指定参数名的值，如果有重复的参数名，则返回第一个的值 接收一般变量 ，如text类型
24      *
25      * @param name 指定参数名
26      * @return 指定参数名的值
27      */
28     @Override
29     public String getParameter(String name) {
30         String[] results = parameterMap.get(name);
31         return results[0];
32     }
33 
34 
35     /**
36      * 获取指定参数名的所有值的数组，如：checkbox的所有数据
37      * 接收数组变量 ，如checkobx类型
38      */
39     @Override
40     public String[] getParameterValues(String name) {
41         return parameterMap.get(name);
42     }
43 
44     @Override
45     public Map<String, String[]> getParameterMap() {
46         return parameterMap;
47     }
48 
49     public void setParameterMap(Map<String, String[]> parameterMap) {
50         this.parameterMap = parameterMap;
51     }
52 }

 1 public class LangFilter implements Filter {
 2     @Override
 3     public void init(FilterConfig filterConfig) throws ServletException {
 4 
 5     }
 6 
 7     @Override
 8     public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
 9 
10         ChangeRequestWrapper changeRequestWrapper = new ChangeRequestWrapper((HttpServletRequest) servletRequest);
11 
12         Map<String, String[]> parameterMap = new HashMap<>(changeRequestWrapper.getParameterMap());
13 
14         String[] strings = parameterMap.get("lang");
           //逻辑代码给定默认的参数值,如果参数不为中文,则直接返回异常
15         if (strings == null || strings.length == 0) {
16             strings = new String[1];
17             strings[0] = "zh";
18             parameterMap.put("lang", strings);
19             changeRequestWrapper.setParameterMap(parameterMap);
20         }else{
21             String language = strings[0];
22             if (!language.equals("zh")) {
23                 Map<String,String> error = new HashMap<>();
24                 error.put("code","500");
25 
26                 ServletOutputStream outputStream = null;
27                 try {
28                     outputStream = servletResponse.getOutputStream();
29                     outputStream.write(JSONUtils.obj2Byte(error));
30                 } finally {
31                     if (outputStream != null) {
32                         outputStream.flush();
33                         outputStream.close();
34                     }
35                 }
36 
37                 return;
38             }
39         }
40         //使用复写后的wrapper
41         filterChain.doFilter(changeRequestWrapper, servletResponse);
42     }
43 
44     @Override
45     public void destroy() {
46 
47     }
48 }

 1 　　<filter>
 2         <filter-name>languageFilter</filter-name>
 3         <filter-class>com.intercepor.LangFilter</filter-class>
 4         <init-param>
 5             <param-name>encoding</param-name>
 6             <param-value>UTF-8</param-value>
 7         </init-param>
 8         <init-param>
 9             <param-name>forceEncoding</param-name>
10             <param-value>true</param-value>
11         </init-param>
12     </filter>
13 
14     <filter-mapping>
15         <filter-name>languageFilter</filter-name>
16         <url-pattern>*.do</url-pattern>
17     </filter-mapping>