SpringのFilterでHttpResponseのBody部を取得する

いい感じの凡例が見つからなかったので作ってみました。
STSのデバック環境下で動作確認済みです。

LoggingFilter.java

@Component
public class LoggingFilter implements Filter {
    private static final Logger log = LoggerFactory.getLogger(LoggingFilter.class.getName());

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {

        HttpServletResponseWrapperEx httpResponseEx = new HttpServletResponseWrapperEx(httpResponse);   
        chain.doFilter(request, httpResponseEx);

        String responseBody = httpResponseEx.getBody();     
        log.debug(responseBody);
    }
}

HttpServletResponseWrapperEx.java

public class HttpServletResponseWrapperEx extends HttpServletResponseWrapper {
    private ServletResponse response;
    private PrintWriterEx writerEx;
    private ServletOutputStreamEx outputStreamEx;

    public HttpServletResponseWrapperEx(HttpServletResponse response) {
        super(response);
        this.response = response;
    }

    @Override
    public ServletOutputStream getOutputStream() throws IOException {

        ServletOutputStream stream = this.response.getOutputStream();

        if (null == this.outputStreamEx) {
            this.outputStreamEx = new ServletOutputStreamEx(stream);
        }

        return this.outputStreamEx;
    }

    @Override
    public PrintWriter getWriter() throws IOException {
        PrintWriter writer = this.response.getWriter();
        this.writerEx = new PrintWriterEx(writer);
        return this.writerEx;
    }

    public String getBody() {
        String result = "";

        if (null != this.outputStreamEx) {
            result = this.outputStreamEx.getBody();
        }
        else if (null != this.writerEx) {
            result = this.writerEx.getBody();
        }

        return result;
    }
}

ServletOutputStreamEx.java

public class ServletOutputStreamEx extends ServletOutputStream {
    private StringBuilder body = new StringBuilder();
    private ServletOutputStream target;

    public ServletOutputStreamEx(ServletOutputStream target) {
        this.target = target;
    }

    @Override
    public boolean isReady() {
        return this.target.isReady();
    }

    @Override
    public void setWriteListener(WriteListener listener) {
        this.target.setWriteListener(listener);     
    }

    @Override
    public void write(int b) throws IOException {
        this.target.write(b);
        byte [] value = new byte[] {(byte)b};
        String temp = new String(value);
        body.append(temp);      
    }

    public String getBody() {
        return this.body.toString();
    }
}

PrintWriterEx.java

public class PrintWriterEx extends PrintWriter {

    private StringBuilder body = new StringBuilder();

    public PrintWriterEx(Writer out) {
        super(out);
    }

    @Override
    public void write(int c) {
        super.write(c);
        this.body.append((char)c);
    }

    @Override
    public void write(char[] chars, int offset, int length) {
        super.write(chars, offset, length);
        this.body.append(chars, offset, length);
    }

    public void write(String string, int offset, int length) {
        super.write(string, offset, length);
        this.body.append(string, offset, length);
    }

    public String getBody() {
        return this.body.toString();
    }
}

適当にサンプルを作って動作を確認。
下記サンプルの場合、PrintWriterExが動作した。

HelloController.java

@Controller
public class HeloController{
    @RequestMapping(value = "/", method = RequestMethod.GET)
    public String index(Model model) {
        model.addAttribute("message", "Hello Springboot");
        return "index";
    }
}

下記サンプルの場合、GET/POSTのどちらの場合もServletOutputStreamExが動作した。

GoodbyeController.java

@RestController
public class GoodbyeController {

    @RequestMapping(path = "/goodbye", method = RequestMethod.GET)
    public String goodbye() {
        return "good bye";
    }

    @RequestMapping(path = "/goodbyebye", method = RequestMethod.POST)
    public String goodbyebye() {
        return "{ message: \"goodbye\" }";
    }
}