允许修改入参和出参的过滤器Filter

新增MyHttpServletRequestWrapper类，否则Request的数据流只允许读一次

import org.springframework.util.StreamUtils;

import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStreamReader;

/**
 * 构建可重写请求对象的Request
 * 解决request.getInputStream()与request.getReader()只能调用一次的问题
 */
public class MyHttpServletRequestWrapper extends HttpServletRequestWrapper {

    private byte[] requestBody = null;

    /**
     * Constructs a request object wrapping the given request.
     *
     * @param request The request to wrap
     * @throws IllegalArgumentException if the request is null
     */
    public MyHttpServletRequestWrapper(HttpServletRequest request) {
        super(request);

        //缓存请求body
        try {
            requestBody = StreamUtils.copyToByteArray(request.getInputStream());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public byte[] getRequestBody() {
        return requestBody;
    }

    /*
    可重写入参
     */
    public void setRequestBody(byte[] requestBody) {
        this.requestBody = requestBody;
    }

    /*
    获取入参
     */
    public String getContent(){
        return new String(requestBody);
    }

    /**
     * 重写 getInputStream()
     */
    @Override
    public ServletInputStream getInputStream() throws IOException {
        if(requestBody == null){
            requestBody= new byte[0];
        }
        final ByteArrayInputStream bais = new ByteArrayInputStream(requestBody);
        return new ServletInputStream() {
            @Override
            public boolean isFinished() {
                return false;
            }

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

            @Override
            public void setReadListener(ReadListener listener) {

            }

            @Override
            public int read() throws IOException {
                return bais.read();
            }
        };
    }

    /**
     * 重写 getReader()
     */
    @Override
    public BufferedReader getReader() throws IOException {
        return new BufferedReader(new InputStreamReader(getInputStream()));
    }
}

新增MyHttpServletResponseWrapper类，增加返回数据流的读取

import javax.servlet.ServletOutputStream;
import javax.servlet.WriteListener;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;
import java.io.*;

/**
 * 构建可重写返回对象的Response
 */
public class MyHttpServletResponseWrapper extends HttpServletResponseWrapper {
    private ByteArrayOutputStream buffer = null;
    private ServletOutputStream out = null;
    private PrintWriter writer = null;

    public MyHttpServletResponseWrapper(HttpServletResponse resp) throws IOException {
        super(resp);
        buffer = new ByteArrayOutputStream();// 真正存储数据的流
        out = new WapperedOutputStream(buffer);
        writer = new PrintWriter(new OutputStreamWriter(buffer));
    }

    @Override
    public ServletOutputStream getOutputStream() throws IOException {
        return out;
    }

    @Override
    public PrintWriter getWriter() throws UnsupportedEncodingException {
        return writer;
    }

    @Override
    public void flushBuffer() throws IOException {
        if (out != null) {
            out.flush();
        }
        if (writer != null) {
            writer.flush();
        }
    }

    @Override
    public void reset() {
        buffer.reset();
    }

    public byte[] getResponseData() throws IOException {
        flushBuffer();
        return buffer.toByteArray();
    }

    public String getContent() throws IOException {
        flushBuffer();
        return buffer.toString();
    }


    private class WapperedOutputStream extends ServletOutputStream {
        private ByteArrayOutputStream bos = null;

        public WapperedOutputStream(ByteArrayOutputStream stream) throws IOException {
            bos = stream;
        }

        @Override
        public void write(int b) throws IOException {
            bos.write(b);
        }

        @Override
        public void write(byte[] b) throws IOException {
            bos.write(b, 0, b.length);
        }

        @Override
        public void write(byte[] b, int off, int len) throws IOException {
            bos.write(b, off, len);
        }

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

        @Override
        public void setWriteListener(WriteListener writeListener) {

        }
    }
}

新增过滤器

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * 重写入参、出参的过滤器Filter
 */
@Component
public class MyTestFilter implements Filter  {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        Filter.super.init(filterConfig);
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest req = (HttpServletRequest) request;
        HttpServletResponse resp = (HttpServletResponse) response;
        MyHttpServletRequestWrapper requestWrapper = new MyHttpServletRequestWrapper(req);
        MyHttpServletResponseWrapper responseWrapper = new MyHttpServletResponseWrapper(resp);

        //入参处理
        requestWrapper.getContent();
        //重定向其他controller
        requestWrapper.getRequestDispatcher("/xxx/xxx").forward(requestWrapper,responseWrapper);

        chain.doFilter(requestWrapper,responseWrapper);

        //返回参数处理
        String json = responseWrapper.getContent();
        //返回打印
        response.getOutputStream().write(json.getBytes());
        response.getOutputStream().flush();
    }

    @Override
    public void destroy() {
        Filter.super.destroy();
    }
}