springboot修改请求参数

Posted 2022-11-30 GW_Cheng

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