1) create a new EncodingFilter
Create a new filter for all requests in the past. The decoding method used to process the request parameters is UTF-8, which solves the Chinese scrambling
/** * Unified coding * @author Administrator */ @WebFilter("/*")//Filter all paths public class EncodingFilter implements Filter { @Override public void init(FilterConfig filterConfig) throws ServletException { // TODO Auto-generated method stub } @Override public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws IOException, ServletException { //1.Strong turn HttpServletRequest request=(HttpServletRequest) req; HttpServletResponse response=(HttpServletResponse) resp; //2.Release chain.doFilter(request, response); } @Override public void destroy() { // TODO Auto-generated method stub } }
2) custom request inherits HttpServletRequestWrapper
HttpServletRequestWrapper implements the HttpServletRequest interface, writes classes to inherit HttpServletRequestWrapper, and then implements three methods: String getParameter(String name), String[] getParameterValues(String name), String[] getParameterValues(String name). They can be changed according to our needs, such as setting characters and removing spaces.
Create the class MyRequest in the EncodingFilter file:
class MyRequest extends HttpServletRequestWrapper{ private HttpServletRequest request; private boolean flag=true; public MyRequest(HttpServletRequest request) { super(request); this.request=request; } @Override public String getParameter(String name) { if(name==null || name.trim().length()==0){ return null; } String[] values = getParameterValues(name); if(values==null || values.length==0){ return null; } return values[0]; } @Override /** * hobby=[eat,drink] */ public String[] getParameterValues(String name) { if(name==null || name.trim().length()==0){ return null; } Map<String, String[]> map = getParameterMap(); if(map==null || map.size()==0){ return null; } return map.get(name); } @Override /** * map{ username=[tom],password=[123],hobby=[eat,drink]} */ public Map<String,String[]> getParameterMap() { /** * First determine the request mode * If post request. Setchar... (UTF-8) * If the value in the map is traversed and encoded for get, it is OK */ String method = request.getMethod(); if("post".equalsIgnoreCase(method)){ try { request.setCharacterEncoding("utf-8"); return request.getParameterMap(); } catch (UnsupportedEncodingException e) { // TODO Auto-generated catch block e.printStackTrace(); } }else if("get".equalsIgnoreCase(method)){ Map<String,String[]> map = request.getParameterMap(); //You need to traverse the map to modify the encoding of each data of value if(flag){ for (String key:map.keySet()) { String[] arr = map.get(key); //Continue traversing array for(int i=0;i<arr.length;i++){ //Code try { arr[i]=new String(arr[i].getBytes("iso8859-1"),"utf-8"); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } } } flag=false; } return map; } return super.getParameterMap(); } }
3) use custom request to complete the coding setting in the filter
... //2. release chain.doFilter(new MyRequest(request), response); ...
In this way, the getParameters method of the wrapper is invoked in servlet to get the parameters, and the conversion process of the character encoding has been completed.
4) test registration
View database: