转载-Spring Boot之 Filter（示例：打印request、response日志）

网上有很多采用spring filter机制打印request/response日志的博客, 大都不能很好工作, 下面这个博客写的不错.

https://blog.csdn.net/jy02268879/article/details/84243950

作者用到了下面两个第三方库, 其中 apache lang3 的 StringUtils 可以使用 Hutool 库代替.  jodd 库是一个非常优秀的工具包.

• import jodd.io.StreamUtil;
• import org.apache.commons.lang3.StringUtils;

pom.xml 引入对应的 jodd-core 包.

            <dependency>
                <groupId>org.jodd</groupId>
                <artifactId>jodd-core</artifactId>
                <version>${jodd.all.version}</version>
            </dependency>

下面内容摘自  https://blog.csdn.net/jy02268879/article/details/84243950

===========================================

Filter（过滤器）

===========================================
一个请求可以被多个过滤器拦截到，会依次进入各个Filter中，放行后直至进入Servlet，Servlet处理请求结束后，回到各个Filter继续执行后面的代码，先执行的Filter，后执行完（Filter是个栈结构，先进后出）。

例如：这里有5个filter: A,B,C,D,E

执行filter的前置处理的顺利是A,B,C,D,E

那么执行filter的后置处理的顺序是E,D,C,B,A

一个请求进来以后的执行顺序：

Filter前置处理---->Interceptor（拦截器）前置处理---->正常的controller处理---->Interceptor后置处理---->Filter后置处理

===========================================
一.用@WebFilter注册过滤器

===========================================

---------------------------------------------------------
 1.实现filter接口，或者继承filter的实现类, 

---------------------------------------------------------

RequestFilter.java 继承OncePerRequestFilter确保一次请求只通过一次该filter。

换言之一次请求不会通过两次RequestFilter，一次请求不会重复执行自定义RequestFilter中的doFilterInternal方法

package com.sid.util.LogRequestResponse;
 
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.annotation.Order;
import org.springframework.web.filter.OncePerRequestFilter;
 
import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.BufferedReader;
import java.io.IOException;
 
/**
 * @program: springboot
 * @description:
 * @author: Sid
 * @date: 2018-11-19 09:21
 * @since: 1.0
 **/
@Order(0)
/**
 * 注册过滤器
 * */
@WebFilter(filterName = "RequestResponseLogFilter", urlPatterns = "/*")
public class RequestFilter extends OncePerRequestFilter {
    private static final Logger logger = LoggerFactory.getLogger(RequestFilter.class);
 
    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
        String path = request.getQueryString();
        String servletPath = request.getServletPath();
        String url = request.getRequestURI();
        RequestWrapper requestWrapper = null;
 
 
        StringBuilder sb = new StringBuilder();
        if (request instanceof HttpServletRequest) {
            requestWrapper = new RequestWrapper(request);
                BufferedReader bufferedReader = requestWrapper.getReader();
                String line;
                while ((line = bufferedReader.readLine()) != null) {
                    sb.append(line);
                }
        }
 
        ResponseWrapper responseWrapper=new ResponseWrapper( response);
 
        if (null == requestWrapper) {
            filterChain.doFilter(request, response);
        } else {
            filterChain.doFilter(requestWrapper, responseWrapper);
        }
        logger.info("========================》  url:" + url + " & queryString:" + path+" & servletPath:"+servletPath);
        logger.info("========================》request uri: {}",request.getRequestURI());
        logger.info("========================》request ContentType: {}",request.getContentType());
        logger.info("========================》request param: {}",sb.toString());
 
        logger.info("========================》response status: {}",response.getStatus());
        logger.info("========================》response ContentType: {}",response.getContentType());
 
 
        String result=new String(responseWrapper.getResponseData());
        ServletOutputStream outputStream = response.getOutputStream();
        outputStream.write(result.getBytes());
        outputStream.flush();
        outputStream.close();
        // 打印response
        logger.info("========================》response return data: {} 	" + result);
 
    }
 
} 

---------------------------------------------------------
 2.在spring-boot启动类上加注解@ServletComponentScan
 ---------------------------------------------------------
 

@SpringBootApplication
@ServletComponentScan
public class App {
    public static void main(String[] args) {
        SpringApplication.run(App.class, args);
    }
}

 ===========================================
 二、用FilterRegistrationBean注册过滤器

===========================================

RequestFilterConfiguration.java

package com.sid.util.LogRequestResponse;
 
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
 
/**
 * @program: springboot
 * @description:
 * @author: Sid
 * @date: 2018-11-19 13:48
 * @since: 1.0
 **/
@Configuration
public class RequestFilterConfiguration {
    @Bean
    public FilterRegistrationBean authFilterRegistrationBean() {
        FilterRegistrationBean registration = new FilterRegistrationBean();
        registration.setFilter(new RequestFilter()); //设置自定义的Filter
        registration.addUrlPatterns("/*");  //设置过滤路径
        registration.setName("RequestFilter"); //设置过滤器名称
        registration.setOrder(1);   //设置过滤器顺序
        //registration.addInitParameter("paramName", "paramValue");  //设置初始化参数 这里不用
        return registration;
    }
} 

----------------------------------------------------
RequestWrapper的实现

----------------------------------------------------

package com.sid.util.LogRequestResponse;
 
import jodd.io.StreamUtil;
import org.apache.commons.lang3.StringUtils;
 
import java.io.*;
import java.nio.charset.Charset;
import java.util.Enumeration;
 
import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
 
 
/**
 * @program: springboot
 * @description:
 * @author: Sid
 * @date: 2018-11-19 12:54
 * @since: 1.0
 **/
public class RequestWrapper extends HttpServletRequestWrapper {
    private final byte[] body;
 
    /**
     * 这个必须加,复制request中的bufferedReader中的值
     * @param request
     * @throws IOException
     */
    public RequestWrapper(HttpServletRequest request) throws IOException {
        super(request);
        body = getBodyString(request);
    }
 
    /**
     * 获取请求Body
     *
     * @param request
     * @return
     */
    public byte[] getBodyString(final ServletRequest request) throws IOException {
        String contentType = request.getContentType();
        String bodyString ="";
 
        if (StringUtils.isNotBlank(contentType) && (contentType.contains("multipart/form-data") || contentType.contains("x-www-form-urlencoded"))){
 
            Enumeration<String> pars=request.getParameterNames();
 
            while(pars.hasMoreElements()){
 
                String n=pars.nextElement();
 
                bodyString+=n+"="+request.getParameter(n)+"&";
 
            }
 
            bodyString=bodyString.endsWith("&")?bodyString.substring(0, bodyString.length()-1):bodyString;
 
            return bodyString.getBytes(Charset.forName("UTF-8"));
 
        }else {
 
            return StreamUtil.readBytes(request.getReader(), "UTF-8");
 
        }
    }
 
 
    @Override
    public BufferedReader getReader() throws IOException {
        return new BufferedReader(new InputStreamReader(getInputStream()));
    }
 
    @Override
    public ServletInputStream getInputStream() throws IOException {
        final ByteArrayInputStream bais = new ByteArrayInputStream(body);
        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();
            }
        };
    }
} 

----------------------------------------------------
ResponseWrapper的实现

----------------------------------------------------

package com.sid.util.LogRequestResponse;
 
import javax.servlet.WriteListener;
import javax.servlet.http.HttpServletResponseWrapper;
 
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
 
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
 
/**
 * @program: springboot
 * @description:
 * @author: Sid
 * @date: 2018-11-19 11:55
 * @since: 1.0
 **/
public class ResponseWrapper extends HttpServletResponseWrapper {
    /**
     * This class implements an output stream in which the data is written into a byte array.
     * The buffer automatically grows as data is written to it. The data can be retrieved using toByteArray() and toString().
     Closing a ByteArrayOutputStream has no effect. The methods in this class can be called after the stream has been closed without generating an IOException.
     */
    private ByteArrayOutputStream buffer = null;//输出到byte array
    private ServletOutputStream out = null;
    private PrintWriter writer = null;
 
    public ResponseWrapper(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, this.getCharacterEncoding()));
    }
 
    /** 重载父类获取outputstream的方法 */
    @Override
    public ServletOutputStream getOutputStream() throws IOException {
        return out;
    }
 
    /** 重载父类获取writer的方法 */
    @Override
    public PrintWriter getWriter() throws UnsupportedEncodingException {
        return writer;
    }
 
    /** 重载父类获取flushBuffer的方法 */
    @Override
    public void flushBuffer() throws IOException {
        if (out != null) {
            out.flush();
        }
        if (writer != null) {
            writer.flush();
        }
    }
 
    @Override
    public void reset() {
        buffer.reset();
    }
 
    /** 将out、writer中的数据强制输出到WapperedResponse的buffer里面，否则取不到数据 */
    public byte[] getResponseData() throws IOException {
        flushBuffer();
        return buffer.toByteArray();
    }
 
    /** 内部类，对ServletOutputStream进行包装 */
    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 boolean isReady() {
            return false;
        }
 
        @Override
        public void setWriteListener(WriteListener listener) {
 
        }
    }
}