springboot修改请求参数

梦里梦外; 2023-02-21 12:57 10阅读 0赞

在开发中有时会遇到需要统一修改请求参数的需求，比如前端对某个请求参数进行了base64加密，后端需要统一进行解密。

这个时候只需要定义一个RequestParameterWrapper，再写一个Filter即可。

import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletRequestWrapper;
    import java.util.HashMap;
    import java.util.Map;
    
    /** * 请求参数修改 */
    public class RequestParameterWrapper extends HttpServletRequestWrapper { 
    
        private Map<String, String[]> params = new HashMap<>();
    
        RequestParameterWrapper(HttpServletRequest request) { 
            super(request);
            //将现有parameter传递给params
            this.params.putAll(request.getParameterMap());
        }
    
    
        void addParameters(Map<String, Object> extraParams) { 
            for (Map.Entry<String, Object> entry : extraParams.entrySet()) { 
                addParameter(entry.getKey(), entry.getValue());
            }
        }
    
        /** * 重写getParameter，代表参数从当前类中的map获取 * * @param name * @return */
        @Override
        public String getParameter(String name) { 
            String[] values = params.get(name);
            if (values == null || values.length == 0) { 
                return null;
            }
            return values[0];
        }
    
        /** * 同上 * * @param name * @return */
        @Override
        public String[] getParameterValues(String name) { 
            return params.get(name);
        }
    
        /** * 添加参数 * * @param name * @param value */
        private void addParameter(String name, Object value) { 
            if (value != null) { 
                // System.out.println(value);
                if (value instanceof String[]) { 
                    params.put(name, (String[]) value);
                } else if (value instanceof String) { 
                    params.put(name, new String[]{ (String) value});
                } else { 
                    params.put(name, new String[]{ String.valueOf(value)});
                }
            }
        }
    }

Filter

import lombok.extern.slf4j.Slf4j;
    import org.apache.commons.lang3.StringUtils;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Component;
    import org.springframework.web.filter.OncePerRequestFilter;
    
    import javax.servlet.FilterChain;
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    import java.net.URLDecoder;
    import java.util.HashMap;
    import java.util.Map;
    import java.util.Objects;
    
    /** * 请求设置 */
    @Component
    @Slf4j
    public class ParamFilter extends OncePerRequestFilter { 
    
       
    
        @Override
        protected void doFilterInternal(HttpServletRequest request,
                                        HttpServletResponse response,
                                        FilterChain chain) throws IOException, ServletException { 
    
    		// 获取你需要的参数
            String param = request.getParameter("key");
            if (StringUtils.isBlank(param)) { 
                chain.doFilter(request, response);
            } else { 
                byte[] bytes = new BASE64Decoder().decodeBuffer(param);
                String decode = new String(bytes);
                Map<String, Object> map = new HashMap<>();
                map.put("key", new String[]{ decode});
                RequestParameterWrapper wrapper = new RequestParameterWrapper(request);
                wrapper.addParameters(map);
                chain.doFilter(wrapper, response);
            }
    
        }
    
    }

这个样在controller获取的key就是base64解密后的字符串了