使用 Java、Jersey、MongoDB 和 Json 的简单记录器 API
Simple Logger API using Java, Jersey, MongoDB and Json
我正在学习 Java+Jersey+MongoDB 组合，为此，我正在尝试创建一个小型记录器 API。很简单：您只需 POST 向服务器发送一个包含记录数据的 Json 文件。
这是我目前的情况。
我的数据库连接器：
public class DBConnector {
private static DB db;
private static MongoClient mongo = null;
public static void init() {
try {
mongo = new MongoClient("localhost", 27017);
} catch (final UnknownHostException e) {
System.out.println("Erro!!!!");
}
db = mongo.getDB("log");
}
public static DB getDb() {
return db;
}
public static void close() {
mongo.close();
}
我的资源：
@Path("/log")
public class LogResource {
private static DBCollection LogCollection = DBConnector.getDb().getCollection("raw_data");
@GET
@Produces(MediaType.TEXT_PLAIN)
public String getIt() {
return "OK you got it!"; // Just to Test
}
@POST
@Consumes(MediaType.APPLICATION_JSON)
public String addLog() {
String json = "{'parameter1' : 'banana','parameter2' : 'orange'}"; // I still don't know how to receive the json file
DBObject dbObject = (DBObject)JSON.parse(json);
LogCollection.insert(dbObject);
return "OK";
}
我的 Main（实际上不是我的。与 Jersey 项目一起提供）：
public class Main {
// Base URI the Grizzly HTTP server will listen on
public static final String BASE_URI = "http://localhost:8080/";
/**
* Starts Grizzly HTTP server exposing JAX-RS resources defined in this application.
* @return Grizzly HTTP server.
*/
public static HttpServer startServer() {
// create a resource config that scans for JAX-RS resources and providers
// in br.ufrj.cos.labia.scdp.ips_bs package
final ResourceConfig rc = new ResourceConfig().packages("br.ufrj.cos.labia.scdp.ips_bs");
// create and start a new instance of grizzly http server
// exposing the Jersey application at BASE_URI
return GrizzlyHttpServerFactory.createHttpServer(URI.create(BASE_URI), rc);
}
/**
* Main method.
* @param args
* @throws IOException
*/
public static void main(String[] args) throws IOException {
final HttpServer server = startServer();
System.out.println(String.format("Jersey app started with WADL available at "
+ "%sapplication.wadl\nHit enter to stop it...", BASE_URI));
System.in.read();
server.stop();
}
}
目前的问题是我收到了一个奇怪的 ExceptionInInitializerError，我不知道如何解决。
我应该指出我在Java中还是个菜鸟。
有什么帮助吗？
编辑：
Jersey app started with WADL available at http://localhost:8080/application.wadl
Hit enter to stop it...
Sep 16, 2015 7:14:20 PM org.glassfish.jersey.internal.Errors logErrors
WARNING: The following warnings have been detected: WARNING: Unknown HK2 failure detected:
MultiException stack 1 of 2
java.lang.ExceptionInInitializerError
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
at org.glassfish.hk2.utilities.reflection.ReflectionHelper.makeMe(ReflectionHelper.java:1350)
at org.jvnet.hk2.internal.ClazzCreator.createMe(ClazzCreator.java:271)
at org.jvnet.hk2.internal.ClazzCreator.create(ClazzCreator.java:365)
at org.jvnet.hk2.internal.SystemDescriptor.create(SystemDescriptor.java:471)
at org.glassfish.jersey.process.internal.RequestScope.findOrCreate(RequestScope.java:162)
at org.jvnet.hk2.internal.Utilities.createService(Utilities.java:2072)
at org.jvnet.hk2.internal.ServiceLocatorImpl.internalGetService(ServiceLocatorImpl.java:767)
at org.jvnet.hk2.internal.ServiceLocatorImpl.getService(ServiceLocatorImpl.java:706)
at org.glassfish.jersey.internal.inject.Injections.getOrCreate(Injections.java:169)
at org.glassfish.jersey.server.model.MethodHandler$ClassBasedMethodHandler.getInstance(MethodHandler.java:284)
at org.glassfish.jersey.server.internal.routing.PushMethodHandlerRouter.apply(PushMethodHandlerRouter.java:74)
at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:109)
at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:112)
at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:112)
at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:112)
at org.glassfish.jersey.server.internal.routing.RoutingStage.apply(RoutingStage.java:92)
at org.glassfish.jersey.server.internal.routing.RoutingStage.apply(RoutingStage.java:61)
at org.glassfish.jersey.process.internal.Stages.process(Stages.java:197)
at org.glassfish.jersey.server.ServerRuntime.run(ServerRuntime.java:301)
at org.glassfish.jersey.internal.Errors.call(Errors.java:271)
at org.glassfish.jersey.internal.Errors.call(Errors.java:267)
at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
at org.glassfish.jersey.internal.Errors.process(Errors.java:267)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:317)
at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:292)
at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:1139)
at org.glassfish.jersey.grizzly2.httpserver.GrizzlyHttpContainer.service(GrizzlyHttpContainer.java:375)
at org.glassfish.grizzly.http.server.HttpHandler.run(HttpHandler.java:224)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:591)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:571)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
at com.test.LogResource<clinit>(LogResource.java:27) // <- Copy and Paste of the line: "private static DBCollection LogCollection = DBConnector.getDb().getCollection("raw_data");"
... 36 more
MultiException stack 2 of 2
java.lang.IllegalStateException: Unable to perform operation: create on com.test.LogResource
at org.jvnet.hk2.internal.ClazzCreator.create(ClazzCreator.java:392)
at org.jvnet.hk2.internal.SystemDescriptor.create(SystemDescriptor.java:471)
at org.glassfish.jersey.process.internal.RequestScope.findOrCreate(RequestScope.java:162)
at org.jvnet.hk2.internal.Utilities.createService(Utilities.java:2072)
at org.jvnet.hk2.internal.ServiceLocatorImpl.internalGetService(ServiceLocatorImpl.java:767)
at org.jvnet.hk2.internal.ServiceLocatorImpl.getService(ServiceLocatorImpl.java:706)
at org.glassfish.jersey.internal.inject.Injections.getOrCreate(Injections.java:169)
at org.glassfish.jersey.server.model.MethodHandler$ClassBasedMethodHandler.getInstance(MethodHandler.java:284)
at org.glassfish.jersey.server.internal.routing.PushMethodHandlerRouter.apply(PushMethodHandlerRouter.java:74)
at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:109)
at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:112)
at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:112)
at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:112)
at org.glassfish.jersey.server.internal.routing.RoutingStage.apply(RoutingStage.java:92)
at org.glassfish.jersey.server.internal.routing.RoutingStage.apply(RoutingStage.java:61)
at org.glassfish.jersey.process.internal.Stages.process(Stages.java:197)
at org.glassfish.jersey.server.ServerRuntime.run(ServerRuntime.java:301)
at org.glassfish.jersey.internal.Errors.call(Errors.java:271)
at org.glassfish.jersey.internal.Errors.call(Errors.java:267)
at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
at org.glassfish.jersey.internal.Errors.process(Errors.java:267)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:317)
at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:292)
at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:1139)
at org.glassfish.jersey.grizzly2.httpserver.GrizzlyHttpContainer.service(GrizzlyHttpContainer.java:375)
at org.glassfish.grizzly.http.server.HttpHandler.run(HttpHandler.java:224)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:591)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:571)
at java.lang.Thread.run(Thread.java:745)
看看这个DBConnector.getDb()。再看DBConnector。除非调用 init，否则 db 永远不会被初始化，因此它始终为 null。因此在初始化之前调用 getDb 将 return null，并且在 null 上调用 getCollection 将导致 NullPointerException，这就是您现在面临的问题。
最简单的解决方法就是做类似
的事情
public static DB getDb() {
if (db == null) {
init();
}
return db;
}
我正在学习 Java+Jersey+MongoDB 组合，为此，我正在尝试创建一个小型记录器 API。很简单：您只需 POST 向服务器发送一个包含记录数据的 Json 文件。
这是我目前的情况。
我的数据库连接器：
public class DBConnector {
private static DB db;
private static MongoClient mongo = null;
public static void init() {
try {
mongo = new MongoClient("localhost", 27017);
} catch (final UnknownHostException e) {
System.out.println("Erro!!!!");
}
db = mongo.getDB("log");
}
public static DB getDb() {
return db;
}
public static void close() {
mongo.close();
}
我的资源：
@Path("/log")
public class LogResource {
private static DBCollection LogCollection = DBConnector.getDb().getCollection("raw_data");
@GET
@Produces(MediaType.TEXT_PLAIN)
public String getIt() {
return "OK you got it!"; // Just to Test
}
@POST
@Consumes(MediaType.APPLICATION_JSON)
public String addLog() {
String json = "{'parameter1' : 'banana','parameter2' : 'orange'}"; // I still don't know how to receive the json file
DBObject dbObject = (DBObject)JSON.parse(json);
LogCollection.insert(dbObject);
return "OK";
}
我的 Main（实际上不是我的。与 Jersey 项目一起提供）：
public class Main {
// Base URI the Grizzly HTTP server will listen on
public static final String BASE_URI = "http://localhost:8080/";
/**
* Starts Grizzly HTTP server exposing JAX-RS resources defined in this application.
* @return Grizzly HTTP server.
*/
public static HttpServer startServer() {
// create a resource config that scans for JAX-RS resources and providers
// in br.ufrj.cos.labia.scdp.ips_bs package
final ResourceConfig rc = new ResourceConfig().packages("br.ufrj.cos.labia.scdp.ips_bs");
// create and start a new instance of grizzly http server
// exposing the Jersey application at BASE_URI
return GrizzlyHttpServerFactory.createHttpServer(URI.create(BASE_URI), rc);
}
/**
* Main method.
* @param args
* @throws IOException
*/
public static void main(String[] args) throws IOException {
final HttpServer server = startServer();
System.out.println(String.format("Jersey app started with WADL available at "
+ "%sapplication.wadl\nHit enter to stop it...", BASE_URI));
System.in.read();
server.stop();
}
}
目前的问题是我收到了一个奇怪的 ExceptionInInitializerError，我不知道如何解决。
我应该指出我在Java中还是个菜鸟。
有什么帮助吗？
编辑：
Jersey app started with WADL available at http://localhost:8080/application.wadl
Hit enter to stop it...
Sep 16, 2015 7:14:20 PM org.glassfish.jersey.internal.Errors logErrors
WARNING: The following warnings have been detected: WARNING: Unknown HK2 failure detected:
MultiException stack 1 of 2
java.lang.ExceptionInInitializerError
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
at org.glassfish.hk2.utilities.reflection.ReflectionHelper.makeMe(ReflectionHelper.java:1350)
at org.jvnet.hk2.internal.ClazzCreator.createMe(ClazzCreator.java:271)
at org.jvnet.hk2.internal.ClazzCreator.create(ClazzCreator.java:365)
at org.jvnet.hk2.internal.SystemDescriptor.create(SystemDescriptor.java:471)
at org.glassfish.jersey.process.internal.RequestScope.findOrCreate(RequestScope.java:162)
at org.jvnet.hk2.internal.Utilities.createService(Utilities.java:2072)
at org.jvnet.hk2.internal.ServiceLocatorImpl.internalGetService(ServiceLocatorImpl.java:767)
at org.jvnet.hk2.internal.ServiceLocatorImpl.getService(ServiceLocatorImpl.java:706)
at org.glassfish.jersey.internal.inject.Injections.getOrCreate(Injections.java:169)
at org.glassfish.jersey.server.model.MethodHandler$ClassBasedMethodHandler.getInstance(MethodHandler.java:284)
at org.glassfish.jersey.server.internal.routing.PushMethodHandlerRouter.apply(PushMethodHandlerRouter.java:74)
at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:109)
at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:112)
at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:112)
at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:112)
at org.glassfish.jersey.server.internal.routing.RoutingStage.apply(RoutingStage.java:92)
at org.glassfish.jersey.server.internal.routing.RoutingStage.apply(RoutingStage.java:61)
at org.glassfish.jersey.process.internal.Stages.process(Stages.java:197)
at org.glassfish.jersey.server.ServerRuntime.run(ServerRuntime.java:301)
at org.glassfish.jersey.internal.Errors.call(Errors.java:271)
at org.glassfish.jersey.internal.Errors.call(Errors.java:267)
at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
at org.glassfish.jersey.internal.Errors.process(Errors.java:267)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:317)
at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:292)
at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:1139)
at org.glassfish.jersey.grizzly2.httpserver.GrizzlyHttpContainer.service(GrizzlyHttpContainer.java:375)
at org.glassfish.grizzly.http.server.HttpHandler.run(HttpHandler.java:224)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:591)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:571)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
at com.test.LogResource<clinit>(LogResource.java:27) // <- Copy and Paste of the line: "private static DBCollection LogCollection = DBConnector.getDb().getCollection("raw_data");"
... 36 more
MultiException stack 2 of 2
java.lang.IllegalStateException: Unable to perform operation: create on com.test.LogResource
at org.jvnet.hk2.internal.ClazzCreator.create(ClazzCreator.java:392)
at org.jvnet.hk2.internal.SystemDescriptor.create(SystemDescriptor.java:471)
at org.glassfish.jersey.process.internal.RequestScope.findOrCreate(RequestScope.java:162)
at org.jvnet.hk2.internal.Utilities.createService(Utilities.java:2072)
at org.jvnet.hk2.internal.ServiceLocatorImpl.internalGetService(ServiceLocatorImpl.java:767)
at org.jvnet.hk2.internal.ServiceLocatorImpl.getService(ServiceLocatorImpl.java:706)
at org.glassfish.jersey.internal.inject.Injections.getOrCreate(Injections.java:169)
at org.glassfish.jersey.server.model.MethodHandler$ClassBasedMethodHandler.getInstance(MethodHandler.java:284)
at org.glassfish.jersey.server.internal.routing.PushMethodHandlerRouter.apply(PushMethodHandlerRouter.java:74)
at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:109)
at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:112)
at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:112)
at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:112)
at org.glassfish.jersey.server.internal.routing.RoutingStage.apply(RoutingStage.java:92)
at org.glassfish.jersey.server.internal.routing.RoutingStage.apply(RoutingStage.java:61)
at org.glassfish.jersey.process.internal.Stages.process(Stages.java:197)
at org.glassfish.jersey.server.ServerRuntime.run(ServerRuntime.java:301)
at org.glassfish.jersey.internal.Errors.call(Errors.java:271)
at org.glassfish.jersey.internal.Errors.call(Errors.java:267)
at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
at org.glassfish.jersey.internal.Errors.process(Errors.java:267)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:317)
at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:292)
at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:1139)
at org.glassfish.jersey.grizzly2.httpserver.GrizzlyHttpContainer.service(GrizzlyHttpContainer.java:375)
at org.glassfish.grizzly.http.server.HttpHandler.run(HttpHandler.java:224)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:591)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:571)
at java.lang.Thread.run(Thread.java:745)
看看这个DBConnector.getDb()。再看DBConnector。除非调用 init，否则 db 永远不会被初始化，因此它始终为 null。因此在初始化之前调用 getDb 将 return null，并且在 null 上调用 getCollection 将导致 NullPointerException，这就是您现在面临的问题。
最简单的解决方法就是做类似
的事情public static DB getDb() {
if (db == null) {
init();
}
return db;
}