如何解决错误:HttpClientErrorException:400 null

Question

我开发了一个rest服务，用于管理与客户有关的crud操作。

现在，我想从我的springmvc应用程序调用我的服务rest，但当我点击jsp页面中的"更新"按钮时，我得到了以下错误：

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is
org.springframework.web.client.HttpClientErrorException: 400 null
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:982)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:866)
javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851)
javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) cause mère
org.springframework.web.client.HttpClientErrorException: 400 null
org.springframework.web.client.DefaultResponseErrorHandler.handleError(DefaultResponseErrorHandler.java:94)
org.springframework.web.client.DefaultResponseErrorHandler.handleError(DefaultResponseErrorHandler.java:79)
org.springframework.web.client.ResponseErrorHandler.handleError(ResponseErrorHandler.java:63)
org.springframework.web.client.RestTemplate.handleResponse(RestTemplate.java:766)
org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:724)
org.springframework.web.client.RestTemplate.execute(RestTemplate.java:680)
org.springframework.web.client.RestTemplate.getForObject(RestTemplate.java:332)
com.luv2code.springdemo.service.CustomerServiceRestClientImpl.getCustomer(CustomerServiceRestClientImpl.java:59)
com.luv2code.springdemo.controller.CustomerController.showFormForUpdate(CustomerController.java:62)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:498)
org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209)
org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136)
org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:877)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:783)
org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:866)
javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851)
javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)

这是我的DemoAppConfig类：

package com.luv2code.springdemo.config;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import org.springframework.web.client.RestTemplate;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
@Configuration
@EnableWebMvc
@ComponentScan("com.luv2code.springdemo")
@PropertySource({ "classpath:application.properties" })
public class DemoAppConfig implements WebMvcConfigurer {
// define a bean for ViewResolver
@Bean
public ViewResolver viewResolver() {
InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
viewResolver.setPrefix("/WEB-INF/view/");
viewResolver.setSuffix(".jsp");
return viewResolver;
}
// define bean for RestTemplate ... this is used to make client REST calls
@Bean
public RestTemplate restTemplate() {
return new RestTemplate();
}
// add resource handler for loading css, images, etc
@Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
registry
.addResourceHandler("/resources/**")
.addResourceLocations("/resources/"); 
}   
}

这是我的文件application.properties:

#
# The URL for the CRM REST API
# - update to match your local environment
#
crm.rest.url=http://localhost:8080/spring-crm-rest/api/customers

这是我的服务级别：

package com.luv2code.springdemo.service;
import java.util.List;
import java.util.logging.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.core.ParameterizedTypeReference;
import org.springframework.http.HttpMethod;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;
import com.luv2code.springdemo.model.Customer;
@Service
public class CustomerServiceRestClientImpl implements CustomerService {
private RestTemplate restTemplate;
private String crmRestUrl;
private Logger logger = Logger.getLogger(getClass().getName());
@Autowired
public CustomerServiceRestClientImpl(RestTemplate theRestTemplate, 
@Value("${crm.rest.url}") String theUrl) {
restTemplate = theRestTemplate;
crmRestUrl = theUrl;
logger.info("Loaded property:  crm.rest.url=" + crmRestUrl);
}
@Override
public List<Customer> getCustomers() {
logger.info("in getCustomers(): Calling REST API " + crmRestUrl);
// make REST call
ResponseEntity<List<Customer>> responseEntity = 
restTemplate.exchange(crmRestUrl, HttpMethod.GET, null, 
new ParameterizedTypeReference<List<Customer>>() {});
// get the list of customers from response
List<Customer> customers = responseEntity.getBody();
logger.info("in getCustomers(): customers" + customers);
return customers;
}
@Override
public Customer getCustomer(int theId) {
logger.info("in getCustomer(): Calling REST API " + crmRestUrl);
// make REST call
Customer theCustomer = 
restTemplate.getForObject(crmRestUrl + "/" + theId, 
Customer.class);
logger.info("in saveCustomer(): theCustomer=" + theCustomer);
return theCustomer;
}
@Override
public void saveCustomer(Customer theCustomer) {
logger.info("in saveCustomer(): Calling REST API " + crmRestUrl);
int employeeId = theCustomer.getId();
// make REST call
if (employeeId == 0) {
// add employee
restTemplate.postForEntity(crmRestUrl, theCustomer, String.class);          
} else {
// update employee
restTemplate.put(crmRestUrl, theCustomer);
}
logger.info("in saveCustomer(): success");  
}
@Override
public void deleteCustomer(int theId) {
logger.info("in deleteCustomer(): Calling REST API " + crmRestUrl);
// make REST call
restTemplate.delete(crmRestUrl + "/" + theId);
logger.info("in deleteCustomer(): deleted customer theId=" + theId);
}
}

这是我的控制器，它在我的休息服务中：

package com.luv2code.springdemo.rest;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.luv2code.springdemo.entity.Customer;
import com.luv2code.springdemo.service.CustomerService;
@RestController
@RequestMapping("/api")
public class CustomerRestController {

// importer la depende du service
@Autowired
private CustomerService customerService;
// ajout de la methode qui permet de récupérer les customers (clients)
@GetMapping("/customers")
public List<Customer> getCustomers(){

return customerService.getCustomers();
}

// récupérer un seul customer avec un id donné en parametre
@GetMapping("/customer/{customerId}")
public Customer getCustomer(@PathVariable int customerId) {
Customer theCustomer = customerService.getCustomer(customerId);
if(theCustomer == null) {
throw new CustomerNotFoundException("Le client avec l'id :"+ customerId + " n'est pas trouvé");
}

return theCustomer;
}
// ajouter la méthode d'ajout d'un nouveau customer
@PostMapping("/customers")
public Customer addCustomer(@RequestBody  Customer theCustomer) {
theCustomer.setId(0);
customerService.saveCustomer(theCustomer);
return theCustomer;
}

// modification d'un customer existent :
@PutMapping("/customers")
public Customer updateCustomer(@RequestBody  Customer theCustomer) {

customerService.saveCustomer(theCustomer);
return theCustomer;
}
// delete un customer en fonction de l'id donné :
@DeleteMapping("/customers/{customerId}")
public String DeleteCustomer(@PathVariable int customerId) {
Customer theCustomer = customerService.getCustomer(customerId);
if(theCustomer == null) {
throw new CustomerNotFoundException("le customer avec l'id donnée n'a pas été trouvé");
}
customerService.deleteCustomer(customerId);;
return "le client avec l'id" + customerId + " a été supprimé";
}
}

这是那些想测试我的应用程序的人的驱动链接：

https://drive.google.com/open?id=1Hko4iSjpR1qV7s1kfWVdLbotWzn1Cvx1

有人能帮帮我吗？

Answer 1

在错误堆栈跟踪中，您可以看到代码的最后一行调用是

com.luv2code.springdemo.service.CustomerServiceRestClientImpl.getCustomer(CustomerServiceRestClientImpl.java:59)

当在该方法中查找时，我发现了这个声明的函数体。

// make REST call
Customer theCustomer = restTemplate.getForObject(crmRestUrl + "/" + theId, 
Customer.class);

400是一个状态代码，所以restTemplate正确地调用了它，但4xx意味着响应服务器说来自客户端的请求格式错误或不正确(所以这不是响应服务器的错误(。所以我开始考虑这个请求。您使用了两个参数，theId是一个输入参数，然后是urlcrmRestUrl。

当查找这些参数的声明位置时，我会发现以下内容。

private String crmRestUrl;

我相信这是null，这可能是你的问题。