java - 我在 lambda 表达式中找不到结果

Question

我将此 json 发送到我的 tomcat 服务

    {
    "room": "Platinum",
    "products": [{
        "name": "Agua",
        "quantity": 2
    }],
    "observation": "",
    "date": "2016-08-15 12:00:00",
    "status": 0
    }

此代码使用我的 json 并在数据库中设置数据。

    @Transactional
    @RequestMapping(value = "/get-order", method = RequestMethod.POST, produces = PRODUCES_JSON)
    public ResponseEntity getOrder(@RequestBody String content)
            throws ParseException, UnsupportedEncodingException {
        try {
            String result = java.net.URLDecoder.decode(content, "UTF-8");
            JSONObject json = new JSONObject(result);

            Order order = createOrder(json);

            @SuppressWarnings("unchecked")
            List products = em.createNamedQuery(Product.QUERY_LIST).getResultList();

            JSONArray productsJsonArray = json.getJSONArray(JSON_PRODUCTS);
            for (int i = 0; i  product = products.stream().filter(p -> p.getName().equals(name)).findAny();
                order.addProduct(product.get(), quantity);
            }
            em.persist(order);


            return buildGetOrderResponse(order);

        } catch (NoResultException e) {
            LOGGER.error(e.getMessage(), e);
            return buildErrorResponse(WebServiceError.NOT_FOUND);
        }
    }

当我运行调试时，显示了此行 order.addProduct(product.get(),Quantity); 中的错误

但是代码在日志错误中返回此内容:

    ago 26, 2016 5:08:12 PM org.apache.catalina.core.StandardWrapperValve invoke
GRAVE: Servlet.service() for servlet [dispatcher] in context with path [/easy-coffee] threw exception [Request processing failed; nested exception is java.util.NoSuchElementException: No value present] with root cause
java.util.NoSuchElementException: No value present
    at java.util.Optional.get(Optional.java:135)
    at br.com.fourward.easycoffee.webservices.ConsummationWebService.getOrder(ConsummationWebService.java:89)
    at br.com.fourward.easycoffee.webservices.ConsummationWebService$$FastClassBySpringCGLIB$$afa221ad.invoke()
    at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:720)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
    at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:281)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:655)
    at br.com.fourward.easycoffee.webservices.ConsummationWebService$$EnhancerBySpringCGLIB$$60d13b8.getOrder()
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:222)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:814)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:737)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:969)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:871)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:845)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:528)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1099)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:670)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1520)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1476)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)

我需要一点帮助，我是 jpa 的新手......谢谢你们

Answer 1

根据 Java 文档，Optional.get()(用作 addProduct 方法的参数)返回一个值，如果没有值，则返回 NoSuchElementException。仅当 Product.isPresent() 返回 true 时才应调用 addProduct()。