1. Why do you need this filter?
Log pain points:
- Request parameters are scattered everywhere?
- Can't the response data be recorded uniformly?
- Are logs severely coupled with business code?
Solution: A Filter intercepts requests and responses simultaneously to achieve log collection automation!
2. Core implementation: A Filter handles two-way data flow
Highlights of filter design
- Request parameter capture: Unified analysis of GET/POST parameters
- Response result interception: Supports text responses such as JSON/XML
- Zero code intrusion: no modification of business code can be implanted
- JDK1.8 is perfectly compatible: no new features dependencies
3. Complete code implementation
1. Filter core code (can be copied directly)
import ;
import ;
import ;
import ;
import ;
import ;
public class RequestResponseLogFilter extends OncePerRequestFilter {
@Override
protected void doFilterInternal(HttpServletRequest request,
HttpServletResponse response,
FilterChain filterChain)
throws ServletException, IOException {
// Package the request response object ContentCachingRequestWrapper wrappedRequest =
new ContentCachingRequestWrapper(request);
ContentCachingResponseWrapper wrappedResponse =
new ContentCachingResponseWrapper(response);
try {
// Execute subsequent filter chains (wrappedRequest, wrappedResponse);
// Logging (core logic) logRequest(wrappedRequest);
logResponse(wrappedResponse);
} finally {
// Response reply must be performed ();
}
}
// Request log method private void logRequest(ContentCachingRequestWrapper request) {
String method = ();
String url = ().toString();
String params = getRequestParams(request);
("[ask] %s %s | parameter=%s%n", method, url, params);
}
// Response log method private void logResponse(ContentCachingResponseWrapper response) throws IOException {
int status = ();
String body = getResponseBody(response);
("[response] Status code=%d | content=%s%n", status, body);
}
// Get request parameters tool method private String getRequestParams(ContentCachingRequestWrapper request) {
try {
if ("GET".equalsIgnoreCase(())) {
return ();
} else {
byte[] body = ();
return new String(body, ());
}
} catch (Exception e) {
return "[Parameter parsing failed]";
}
}
// Method for obtaining response content private String getResponseBody(ContentCachingResponseWrapper response) throws IOException {
byte[] content = ();
return new String(content, ());
}
@Override
public void init(FilterConfig filterConfig) {}
@Override
public void destroy() {}
}
4. Add filters in three steps
1. Add dependencies (Maven configuration)
<!-- Core packaging -->
<dependency>
<groupId></groupId>
<artifactId>tomcat-catalina</artifactId>
<version>9.0.65</version>
</dependency>
2. Configuration (traditional project)
<filter>
<filter-name>RequestResponseLogFilter</filter-name>
<filter-class></filter-class>
</filter>
<filter-mapping>
<filter-name>RequestResponseLogFilter</filter-name>
<url-pattern>/*</url-pattern> <!-- Intercept all requests -->
<dispatcher>REQUEST</dispatcher>
</filter-mapping>
3. Spring Boot Integration (New Project Recommendation)
@Bean
public FilterRegistrationBean<RequestResponseLogFilter> logFilter(){
FilterRegistrationBean<RequestResponseLogFilter> registrationBean = new FilterRegistrationBean<>();
(new RequestResponseLogFilter());
("/*");
return registrationBean;
}
5. Running effect demonstration
[REQUEST] POST http://api/user/login | Parameters =username=admin&password=123456 | Time=Wed Oct 05 14:30:00 CST 2023
[RESPONSE] Status code=200 | Response content={"code":0,"msg":"Login successfully"} | Time taken=120ms
6. 6 major things to pay attention to
1. Memory overflow risk
Intercept large files to upload (>1MB) will take up a lot of memory
Solution: Limit cache size
// Set the maximum cache in the constructornew ContentCachingRequestWrapper(request, 1024 * 1024); // 1MB
2. Coding compatibility issues
The garbled code of the request parameters is often caused by the lack of encoding settings.
Force encoding (added in Filter header)
("UTF-8");
("UTF-8");
3. Response stream secondary read
The original response stream can only be read once, and the wrapper class must be used.
Error writing: Use original() directly
4. Sensitive information leakage
Fields such as password need to be filtered (regular replacement example)
("password=\\w+", "password=***");
5. Performance loss control
High concurrency scenarios suggest logging asynchronously
(() -> (logContent));
Support
Make sure Tomcat is configured correctly:
<Connector port="8443" protocol=".http11.Http11NioProtocol"
SSLEnabled="true" scheme="https" secure="true"/>
7. Advanced gameplay
Combination use:
Implement method level log with Spring AOP
Combined with Redis to implement request current limit
Data Analysis:
-- Log AnalysisSQLExample
SELECT
request_uri,
COUNT(*) as total,
AVG(response_time) as avg_time
FROM access_log
WHERE status >= 500
GROUP BY request_uri;
Summary
An excellent Filter is like a "digital surveillance camera", silently recording the system's operating trajectory. Through this article's solution, you can:
- Unified management of all request response logs
- Realize full-link tracking at zero cost
- Flexible expansion of monitoring dimensions
This is the article about springboot filter implementing request response full-link interception. For more related contents of springboot filter request interception, please search for my previous articles or continue browsing the related articles below. I hope everyone will support me in the future!