嗨，伙计们，我正在解决这个问题，希望我能在这里得到一些帮助。
我的问题： - 我正在使用角度js作为前端，并使用rest api将其连接到后端。在我的一些部分内部角js或我们可以说一些HTML页面，我能够成功GET，但只有一个HTML页面或部分GET说内部服务器错误500 .i尝试调试我的浏览器以及显示的是angular.js。 - GET localhost：8080 / mytracker / getDeviceList.do 500（内部服务器错误） -
困惑： - 我的困惑是角度js代码或我的后端代码是问题，这是我在spring写的rest api代码。问题是因为我得到了text / html格式的数据 .for 其他html页面我能够进入application / json 。可能是我后端的问题。
发布我的后端代码： -
DeviceController.java - ＆gt;
@Controller
public class DeviceController {
@Autowired DeviceDAO deviceDAO;
@RequestMapping(value="/getDeviceList",method=RequestMethod.GET, produces=MediaType.APPLICATION_JSON_VALUE)
public @ResponseBody List<DeviceForm> getdevice()
{
List<DeviceForm> deviceForms=new ArrayList<DeviceForm>();
List<Device> devices= deviceDAO.getAllDevices();
for(Device device:devices)
{
DeviceForm deviceForm= new DeviceForm();
deviceForm.setDeviceNumber(device.getDeviceNo());
deviceForm.setDeviceId(device.getDeviceId());
deviceForm.setPurchaseDate(device.getPurchaseData().toString());
deviceForm.setExpiryDate(device.getExpiryDate().toString());
deviceForm.setClientId(device.getDeviceClienid());
deviceForms.add(deviceForm);
}
return deviceForms;
}
我的自动装配如下： -
public interface DeviceDAO {
public List<Device> getAllDevices();
public void saveDevice(Device device);
}
我的 DeviceForm类： - ＆gt;
private double deviceId;
private String purchaseDate;
private String warrantyPeriod;
private String warEndDate;
private String clientId;
private String warrantedDays;
private String warStartDate;
private String warranty;
private String deviceNumber;
private String expiryDate;
private long vehicleId;
private String deviceStatus;
public double getDeviceId() {
return deviceId;
}
public void setDeviceId(double deviceId) {
this.deviceId = deviceId;
}
public long getVehicleId() {
return vehicleId;
}
public void setVehicleId(long vehicleId) {
this.vehicleId = vehicleId;
}
public String getExpiryDate() {
return expiryDate;
}
public void setExpiryDate(String expiryDate) {
this.expiryDate = expiryDate;
}
public String getDeviceNumber() {
return deviceNumber;
}
public void setDeviceNumber(String deviceNumber) {
this.deviceNumber = deviceNumber;
}
public String getWarranty() {
return warranty;
}
public void setWarranty(String warranty) {
this.warranty = warranty;
}
public String getPurchaseDate() {
return purchaseDate;
}
public void setPurchaseDate(String purchaseDate) {
this.purchaseDate = purchaseDate;
}
public String getWarrantyPeriod() {
return warrantyPeriod;
}
public void setWarrantyPeriod(String warrantyPeriod) {
this.warrantyPeriod = warrantyPeriod;
}
public String getWarEndDate() {
return warEndDate;
}
public void setWarEndDate(String warEndDate) {
this.warEndDate = warEndDate;
}
public String getWarrantedDays() {
return warrantedDays;
}
public void setWarrantedDays(String warrantedDays) {
this.warrantedDays = warrantedDays;
}
public String getWarStartDate() {
return warStartDate;
}
public void setWarStartDate(String warStartDate) {
this.warStartDate = warStartDate;
}
public String getClientId() {
return clientId;
}
public void setClientId(String clientId) {
this.clientId = clientId;
}
}
我在角色前端中使用这些休息类，使用在角度控制器中编写的代码，如下所示： - ＆gt;
myApp.controller("DeviceManagementController",['$scope','$http',function($scope,$http){
$scope.gridOptions = {
pagingPageSizes: [25, 50, 75],
pagingPageSize: 25,
columnDefs: [
{ name: 'deviceId' },
{ name: 'deviceNumber' },
{ name: 'purchaseDate' },
{ name: 'expiryDate' }
],
$http.get('http://localhost:8080/mytracker/getDeviceList.do')
.success(function (data) {
$scope.gridOptions.data = data;
});
}]);
我的完整stackTrace是： -
Jan 12, 2015 5:11:15 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [mytracker] in context with path [/mytracker] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause
java.lang.NullPointerException
at com.dataisys.mytracker.web.controller.DeviceController.getdevice(DeviceController.java:44)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:213)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:126)
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(AbstractHandlerMethodA dapter.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.doGet(FrameworkServlet.java:778)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Unknown Source)
希望得到建议!!!!
答案 0 :(得分：0)
信息很清楚。
你有一个NPE：在你的getdevice方法中。
java.lang.NullPointerException
at com.dataisys.mytracker.web.controller.DeviceController.getdevice(DeviceController.java:44)
看起来deviceDAO为null。
答案 1 :(得分：0)
这种情况正在发生，因为您从 getExpiryDate（）获得的结果为空。因此，请确保数据库表中您从中获取数据的列不为空。然后我想一切都会好起来的。