json - Spring REST 服务 : retrieving JSON from Request

Question

我正在 Spring 3.1 上构建 REST 服务。我为此使用@EnableWebMVC 注释。由于我的服务将只接受 JSON 请求，我还想将传入的请求转储到 MongoDB 集合中以进行日志记录(以及稍后用于数据转换)。我想访问原始 JSON 请求(我可以在非 Spring 实现上使用“@Content HttpServletRequest 请求”作为方法参数)。

我是 Spring 新手。所以，请帮助我实现这一目标。谢谢!

更新:问题尚未完全解决。只有我的 GET 测试有效。 POST 失败。因此未选中接受的答案

问题是，即使我创建了一个 HttpServletRequestWrapper，我也无法在处理和包装请求后转发请求。这是发生了什么:

拦截器:

public class DBLogInterceptor extends HandlerInterceptorAdapter {
    MyRequestWrapper requestWrapper;

    private final static Logger logger = Logger.getLogger(DBLogInterceptor.class);

    @Override
    public boolean preHandle(
            HttpServletRequest request,
            HttpServletResponse response,
            Object handler) throws Exception 
    {
        requestWrapper = new MyRequestWrapper(request);
        // Code removed, but it just dumps requestWrapper.getBody() into DB
        return super.preHandle(requestWrapper, response, handler);
    }
}

HTTP POST 服务方式

@RequestMapping(method = RequestMethod.POST, consumes="application/json", produces="application/json", value = "employee")
@ResponseBody
public String updateEntity(@RequestBody Employee emp) {
    // Do some DB Stuff. Anyway, the control flow does not reach this place.
    return "Employee " + emp.getName() + " updated successfully!";
}

现在每当我发送 POST 时都会收到异常:

12:04:53,821 DEBUG DBLogInterceptor:22 - {"name":"Van Damme","dept":"Applied Martial Arts"}
12:04:53,843 DEBUG RequestResponseBodyMethodProcessor:117 - Reading [com.test.webapp.login.domain.Employee] as "application/json" using [org.springframework.http.converter.json.MappingJacksonHttpMessageConverter@154174f9]
12:04:53,850 DEBUG ExceptionHandlerExceptionResolver:132 - Resolving exception from handler [public java.lang.String com.test.webapp.controller.EmployeeService.updateEntity(com.test.webapp.login.domain.Employee)]: java.io.IOException: Stream closed
12:04:53,854 DEBUG ResponseStatusExceptionResolver:132 - Resolving exception from handler [public java.lang.String com.test.webapp.controller.EmployeeService.updateEntity(com.test.webapp.login.domain.Employee)]: java.io.IOException: Streamclosed
12:04:53,854 DEBUG DefaultHandlerExceptionResolver:132 - Resolving exception from handler [public java.lang.String com.test.webapp.controller.EmployeeService.updateEntity(com.test.webapp.login.domain.Employee)]: java.io.IOException: Streamclosed
12:04:53,859 DEBUG DispatcherServlet:910 - Could not complete request
java.io.IOException: Stream closed
        at org.apache.catalina.connector.InputBuffer.read(InputBuffer.java:312)
        at org.apache.catalina.connector.CoyoteInputStream.read(CoyoteInputStream.java:200)
        at org.codehaus.jackson.impl.ByteSourceBootstrapper.ensureLoaded(ByteSourceBootstrapper.java:507)
        at org.codehaus.jackson.impl.ByteSourceBootstrapper.detectEncoding(ByteSourceBootstrapper.java:129)
        at org.codehaus.jackson.impl.ByteSourceBootstrapper.constructParser(ByteSourceBootstrapper.java:224)
        at org.codehaus.jackson.JsonFactory._createJsonParser(JsonFactory.java:785)
        at org.codehaus.jackson.JsonFactory.createJsonParser(JsonFactory.java:561)
        at org.codehaus.jackson.map.ObjectMapper.readValue(ObjectMapper.java:1914)
        at org.springframework.http.converter.json.MappingJacksonHttpMessageConverter.readInternal(MappingJacksonHttpMessageConverter.java:124)
        at org.springframework.http.converter.AbstractHttpMessageConverter.read(AbstractHttpMessageConverter.java:153)
        at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodArgumentResolver.readWithMessageConverters(AbstractMessageConverterMethodArgumentResolver.java:120)
        at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodArgumentResolver.readWithMessageConverters(AbstractMessageConverterMethodArgumentResolver.java:91)
        at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.resolveArgument(RequestResponseBodyMethodProcessor.java:71)
        at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:75)
        at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:156)
        at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:117)
        at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:96)
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:617)
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:578)
        at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
        at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:923)
        at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852)
        at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
        at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:789)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:225)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
        at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
        at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
        at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:999)
        at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:565)
        at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:307)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
        at java.lang.Thread.run(Unknown Source)

我希望 HttpServletRequestWrapper 负责缓存请求。但它不会以某种方式发生。

Answer 1

使用 HttpServletRequest对象，您可以访问客户端用于发出请求的 URL、使用的方法(GET、POST、PUT 等)、查询字符串和 header 。

获取 RequestBody 可能有点棘手，可能需要使用 HttpServletRequestWrapper目的。由于请求正文只能读取一次，因此您需要扩展包装器以访问它，以便您的目标 Controller 稍后仍可以访问它以将您的 JSON 反序列化为 POJO 对象。

public class MyRequestWrapper extends HttpServletRequestWrapper {
 private final String body;
 public MyRequestWrapper(HttpServletRequest request) throws IOException {
   super(request);
   StringBuilder stringBuilder = new StringBuilder();
   BufferedReader bufferedReader = null;
   try {
     InputStream inputStream = request.getInputStream();
     if (inputStream != null) {
       bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
       char[] charBuffer = new char[128];
       int bytesRead = -1;
       while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
         stringBuilder.append(charBuffer, 0, bytesRead);
       }
     } else {
       stringBuilder.append("");
     }
   } catch (IOException ex) {
       throw ex;
   } finally {
     if (bufferedReader != null) {
       try {
         bufferedReader.close();
       } catch (IOException ex) {
         throw ex;
       }
     }
   }
   body = stringBuilder.toString();
 }

 @Override
 public ServletInputStream getInputStream() throws IOException {
   final ByteArrayInputStream byteArrayInputStream = new     ByteArrayInputStream(body.getBytes());
   ServletInputStream servletInputStream = new ServletInputStream() {
     public int read() throws IOException {
       return byteArrayInputStream.read();
     }
   };
   return servletInputStream;
 }

 @Override
 public BufferedReader getReader() throws IOException {
   return new BufferedReader(new InputStreamReader(this.getInputStream()));
 }

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

要在中心位置访问请求，您可以使用过滤器或 Spring 拦截器。这两个都是在请求被委托(delegate)给 Controller 之前调用的，并且都可以访问 servlet。

这里是 actual Logging example using a Spring Interceptor :

package com.vaannila.interceptor;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.log4j.BasicConfigurator;
import org.apache.log4j.Logger;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.handler. HandlerInterceptorAdapter;

public class LoggerInterceptor extends HandlerInterceptorAdapter {
    static Logger logger = Logger.getLogger(LoggerInterceptor.class);

    static {
        BasicConfigurator.configure();
    }

    @Override

    public boolean preHandle(HttpServletRequest request,
        HttpServletResponse response, Object handler) throws Exception {

        logger.info("Before handling the request");
        return super.preHandle(request, response, handler);
    }

    @Override
    public void postHandle(HttpServletRequest request,
        HttpServletResponse response, Object handler,
            ModelAndView modelAndView) throws Exception {

        logger.info("After handling the request");
        super.postHandle(request, response, handler, modelAndView);
    }

    @Override
    public void afterCompletion(HttpServletRequest request,
        HttpServletResponse response, Object handler, Exception ex)
            throws Exception {

        logger.info("After rendering the view");
        super.afterCompletion(request, response, handler, ex);
    }
}


<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:p="http://www.springframework.org/schema/p"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="viewResolver" class="org.springframework.web.servlet.view.    InternalResourceViewResolver" p:prefix="/WEB-INF/jsp/" p:suffix=".jsp" />

    <bean id="handlerMapping" class="org.springframework.web.servlet.handler. BeanNameUrlHandlerMapping" p:interceptors-ref="loggerInterceptor" />

    <bean id="loggerInterceptor" class="com.vaannila.interceptor.LoggerInterceptor" />

    <bean id="userService" class="com.vaannila.service.UserServiceImpl" />

    <bean name="/userRegistration.htm" class="com.vaannila.web.UserController" p:userService-ref="userService" p:formView="userForm" p:successView="userSuccess" />

</beans>

在 LoggerInterceptor 中，您可以使用以下代码来访问请求:

MyRequestWrapper myRequestWrapper = new MyRequestWrapper((HttpServletRequest) request);

String body = myRequestWrapper.getBody();
String clientIP = myRequestWrapper.getRemoteHost();
int clientPort = request.getRemotePort();
String uri = myRequestWrapper.getRequestURI();

System.out.println(body);
System.out.println(clientIP);
System.out.println(clientPort);
System.out.println(uri);