springboot使用拦截器进行校验token(post和get获取token参数)

前言

前面我做了一个简单的jwt校验token的demo案例，再后来的开发过程中我遇到一个问题：我们前台在调用后台接口时，用的最多的contentType是application/x-www-form-urlencoded、application/josn两种类型。当是application/x-www-form-urlencoded类型下，我们在拦截中可以直接使用request.getParameter(“token”) 获取token,而application/josn类型下参数存在body中，我们可以用流进行读取，但是到controller后就无法获取参数了，因为springmvc是这样定义的。我找了一些资料，发现可以使用自定义过滤器，通过改造过滤器的request进行解决。

代码

1.RequestWrapper

mport javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.*;
public class RequestWrapper extends HttpServletRequestWrapper {
    private final String body;

    public RequestWrapper(HttpServletRequest request) {
        super(request);
        StringBuilder stringBuilder = new StringBuilder();
        BufferedReader bufferedReader = null;
        InputStream inputStream = null;
        try {
            inputStream = request.getInputStream();
            if (inputStream != null) {
                bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
                char[] charBuffer = new char[128];
                int bytesRead = -1;
                while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
                    stringBuilder.append(charBuffer, 0, bytesRead);
                }
            } else {
                stringBuilder.append("");
            }
        } catch (IOException ex) {
            ex.printStackTrace();
        } finally {
            if (inputStream != null) {
                try {
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (bufferedReader != null) {
                try {
                    bufferedReader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        body = stringBuilder.toString();
    }
    @Override
    public ServletInputStream getInputStream() {
        final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(body.getBytes());
        ServletInputStream servletInputStream = new ServletInputStream() {
            @Override
            public boolean isFinished() {
                return false;
            }

            @Override
            public boolean isReady() {
                return false;
            }

            @Override
            public void setReadListener(ReadListener readListener) {
            }

            @Override
            public int read() {
                return byteArrayInputStream.read();
            }
        };
        return servletInputStream;

    }
   @Override
    public BufferedReader getReader() {
        return new BufferedReader(new InputStreamReader(this.getInputStream()));
    }
    public String getBody() {
        return this.body;
    }
}

自定义过滤器

@Component
@WebFilter(urlPatterns = "/*", filterName = "channelFilter")
public class ChannelsFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) {

    }
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        ServletRequest requestWrapper = null;
        if (servletRequest instanceof HttpServletRequest) {
        	//关注点
            if (servletRequest.getContentType().equals("application/json")) {
                requestWrapper = new RequestWrapper((HttpServletRequest) servletRequest);
            }
        }
        if (requestWrapper == null) {
            filterChain.doFilter(servletRequest, servletResponse);
        } else {
            filterChain.doFilter(requestWrapper, servletResponse);
        }
    }
    @Override
    public void destroy() {
    }
}

token校验拦截器

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.foxconn.response.ResponseEntity;
import com.foxconn.util.JwtUtil;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;

/**
 * 拦截器拦截进行token验证
 */
public class JwtHandlerInterceptor extends HandlerInterceptorAdapter {
    /**
     * 在请求处理之前进行调用（Controller方法调用之前）
     *
     * @param request
     * @param response
     * @param handler
     * @return
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        String contentType = request.getHeader("content-type");
        String token = "";
        //关注点
        if (contentType.equals("application/x-www-form-urlencoded")) {
            token = request.getParameter("token");
        } else if (contentType.equals("application/json")) {
            RequestWrapper requestWrapper = new RequestWrapper(request);
            String body = requestWrapper.getBody();
            JSONObject datas = JSONObject.parseObject(body);
            token = (String) datas.get("token");
        }
        ResponseEntity res = JwtUtil.parseToken(token);
        if (res.getCode() == 200) return true;
        else {
            response.setCharacterEncoding("UTF-8");
            response.setContentType("application/json; charset=utf-8");
            PrintWriter writer = response.getWriter();
            writer.println(JSON.toJSONString(res));
            return false;
        }
    }
}

记得在springboot启动类上加上filter扫描注解@ServletComponentScan

参考：
https://www.jianshu.com/p/69c6fba08c92