ServletRequest的getReader和getInputStream只能调用一次问题处理

ServletRequest的getReader和getInputStream只能调用一次问题

一.问题背景

spring增加过滤器处理请求，会有报错，== ServletRequest的getReader和getInputStream只能调用一次==，原来是不能多次调用

二.解决方式

1.自定义装饰类，继承 == HttpServletRequestWrapper ==

import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.lang3.StringUtils;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.BufferedReader;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;
import java.util.Vector;

/**
 * 请求参数 装饰类
 * @auth beichen
 */
public class ParameterRequestWrapper extends HttpServletRequestWrapper {
    private byte[] body;
    private Map<String, String[]> params = new HashMap<>();

    /**
     * Constructs a request object wrapping the given request.
     *
     * @param request
     * @throws IllegalArgumentException if the request is null
     */
    public ParameterRequestWrapper (HttpServletRequest request) throws IOException {
        super(request);
        //将参数表，赋予给当前的Map以便于持有request中的参数
        this.params.putAll(request.getParameterMap());
        if(ServletFileUpload.isMultipartContent(request)){
            return;
        }
        StringBuilder sb = new StringBuilder();
        String line;
        BufferedReader reader = request.getReader();
        while ((line = reader.readLine()) != null) {
            sb.append(line);
        }
        String body = sb.toString();
        this.body = body.getBytes(StandardCharsets.UTF_8);
    }

    /**
     * 重载构造方法
     */
    public ParameterRequestWrapper(HttpServletRequest request, Map<String, Object> extendParams) throws IOException {
        this(request);
        //这里将扩展参数写入参数表
        addAllParameters(extendParams);
    }

    /**
     * 在获取所有的参数名,必须重写此方法，否则对象中参数值映射不上
     *
     * @return
     */
    @Override
    public Enumeration<String> getParameterNames() {
        return new Vector(params.keySet()).elements();
    }

    /**
     * 重写getParameter方法
     *
     * @param name 参数名
     * @return 返回参数值
     */
    @Override
    public String getParameter(String name) {
        String[] values = params.get(name);
        if (values == null || values.length == 0) {
            return null;
        }
        return values[0];
    }

    @Override
    public String[] getParameterValues(String name) {
        String[] values = params.get(name);
        if (values == null || values.length == 0) {
            return null;
        }
        return values;
    }

    /**
     * 增加多个参数
     *
     * @param otherParams 增加的多个参数
     */
    public void addAllParameters(Map<String, Object> otherParams) {
        for (Map.Entry<String, Object> entry : otherParams.entrySet()) {
            addParameter(entry.getKey(), entry.getValue());
        }
    }

    /**
     * 增加参数
     *
     * @param name  参数名
     * @param value 参数值
     */
    public void addParameter(String name, Object value) {
        if (value != null) {
            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)});
            }
        }
    }
    public String getBody() {
        return body == null?"":new String(this.body , StandardCharsets.UTF_8);
    }
}

二.增加自定义过滤器

import com.alibaba.fastjson.JSONObject;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.springframework.web.filter.OncePerRequestFilter;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.BufferedReader;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;

import static com.ogc.standard.api.APIHttpUrlToCodeMap.convertHttpUrl;

@Slf4j
@WebFilter(filterName = "MyFilter", urlPatterns = {"/api/front/*"})
public class RequestParameterFilter extends OncePerRequestFilter {
    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
        try{
            Map params = new HashMap();
            /*如果请求路径是为app,进行过滤对参数parameter内容解密，放入request.parameter中*/
            if (request.getHeader("client").equals("ios") || request.getHeader("client").equals("android")) {
                ParameterRequestWrapper wrapper = new ParameterRequestWrapper(request,params);
              
                filterChain.doFilter(wrapper, response);
                return;
            }
        }catch (Exception e){
            e.printStackTrace();
        }
        filterChain.doFilter(request, response);
    }
}