spring boot RestController get HttpServletResponse content - spring-boot

Question

I use spring boot build project, RestController return string data.
I want get response content in Filter.
But cant get, please help me.
controller:
#RestController
#RequestMapping(value = "/service/example")
public class ExampleController {
#RequestMapping(value = "/get/test", method = RequestMethod.POST)
public String message(#RequestBody String data) {
return "test";
}
#RequestMapping(value = "/get/test1", method = RequestMethod.POST)
public void message(HttpServletRequest request, HttpServletResponse response) throws IOException {
PrintWriter writer = response.getWriter();
writer.write("dfsfd");
writer.flush();
}
}
filter:
#WebFilter(filterName="myFilter",urlPatterns="/service/*")
public class MyFilter extends OncePerRequestFilter {
#Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
throws ServletException, IOException {
MyHttpServletResponseWrapper responseWrapper = new MyHttpServletResponseWrapper(response);
filterChain.doFilter(request, responseWrapper);
String responseContent = responseWrapper.getContent();
System.out.println("response="+responseContent);
}
}
MyHttpServletResponseWrapper :
public class MyHttpServletResponseWrapper extends HttpServletResponseWrapper {
private PrintWriter cachedWriter;
private CharArrayWriter bufferedWriter;
/**
* Constructs a response adaptor wrapping the given response.
*
* #param response The response to be wrapped
* #throws IllegalArgumentException if the response is null
*/
public MyHttpServletResponseWrapper(HttpServletResponse response) {
super(response);
bufferedWriter = new CharArrayWriter();
cachedWriter = new PrintWriter(bufferedWriter);
}
#Override
public PrintWriter getWriter() throws IOException {
return cachedWriter;
}
/**
* 获取原始HTML
*
* #return
*/
public String getContent() {
byte[] bytes = bufferedWriter.toString().getBytes();
try {
return new String(bytes, "UTF-8");
} catch (UnsupportedEncodingException e) {
return "";
}
}
}
post to /service/example/get/test cant get content.
but post to /service/example/get/test1 can get content.
why?
My project has many rest like /service/example/get/test, I dont want to change each one.
how to get response content in filter, please help, Thanks!!!

Answer 1

I created one simple spring boot project, in this project you can control which url you want to filter:
Rest service class (3 services, we will filter 2 only)
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.filter.GenericFilterBean;
#SpringBootApplication
#RestController
#RequestMapping(value = "/service/example")
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
#RequestMapping(value = "/get/test", method = RequestMethod.POST)
public String message(#RequestBody String data) {
return "test";
}
#RequestMapping(value = "/get/test1", method = RequestMethod.POST)
public void message(HttpServletRequest request, HttpServletResponse response) throws IOException {
PrintWriter writer = response.getWriter();
writer.write("dfsfd");
writer.flush();
}
#RequestMapping(value = "/api", method = RequestMethod.POST)
public void messages(HttpServletRequest request, HttpServletResponse response) throws IOException {
PrintWriter writer = response.getWriter();
writer.write("dfsfd");
writer.flush();
}
#Bean
public FilterRegistrationBean someFilterRegistration() {
FilterRegistrationBean registration = new FilterRegistrationBean();
registration.setFilter(myFilter());
registration.addUrlPatterns("/service/example/get/*");
registration.setOrder(1);
return registration;
}
#Bean(name = "someFilter")
public GenericFilterBean myFilter() {
return new MyFilter();
}
}
MyFilter class:
import java.io.IOException;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import org.springframework.web.filter.GenericFilterBean;
public class MyFilter extends GenericFilterBean {
#Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain)
throws IOException, ServletException {
System.out.println("Filter called");
filterChain.doFilter(servletRequest, servletResponse);
}
}
try to call 3 services:
http://localhost:8080/service/example/get/test
http://localhost:8080/service/example/get/test1
http://localhost:8080/service/example/api
and check the printed log.
you can control the url patter using this line
registration.addUrlPatterns("/service/example/get/*");
I hope this sample help you, thanks