我的网络服务是用 jersy(restful java)制作的，我使用 Hibernate 与 mysql 数据库进行通信。
白天我执行负载测试和其他功能测试，一切正常，我们在晚上 5 点左右离开工作，当我们第二天早上通过 http 500 异常再次测试我的 Web 服务时，当我们重新启动托管它的 tomcat，我的 Web 服务在不对源代码或 hibernate 配置文件进行任何更改的情况下恢复。
我正在使用相同的 Hibernate 配置文件，该文件已被其他工作正常的 Web 服务使用
这是我的 hibernate 配置文件:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost:3306/offerstest</property>
<property name="hibernate.connection.username">root</property>
<property name="show_sql">true</property>
<property name="connection.password">password</property>
<property name="hibernate.c3p0.min_size">5</property>
<property name="hibernate.c3p0.max_size">20</property>
<property name="hibernate.c3p0.acquire_increment">1</property>
<property name="hibernate.c3p0.timeout">300</property>
<property name="hibernate.c3p0.idle_test_period">3000</property>
<property name="hibernate.c3p0.max_statements">50</property>
<property name="hibernate.jdbc.batch_size">20</property>
<property name="hibernate.cache.use_second_level_cache">false</property>
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hbm2ddl.auto">update</property>
<property name="dynamic-update">true</property>
<mapping resource="person.hbm.xml"/>
<mapping resource="vendor.hbm.xml"/>
<mapping resource="coupons.hbm.xml"/>
<mapping resource="binding.hbm.xml"/>
</session-factory>
</hibernate-configuration>
这是我的 web 服务类，其中出现 Http 500 错误
@Path("/offers")
public class VendorOffers {
VendorCRUD vendorCRUD;
BindingCRUD bindingCRUD;
public VendorOffers() {
// TODO Auto-generated constructor stub
}
@PostConstruct
public void init() {
vendorCRUD = CommunicationSingleton.getInstance().getVendorCRUD();
bindingCRUD = CommunicationSingleton.getInstance().getBindingCRUD();
}
@GET
@Produces(MediaType.APPLICATION_JSON)
// @Produces(MediaType.APPLICATION_XML)
@Path("{mac}/coupons")
public Response getOffers(@PathParam("mac") String mac) {
List<Offer> list = new ArrayList<Offer>();
// get all the offers (Bindings) for the given mac
List<Binding> bindings = bindingCRUD.getMACOffers(mac);
if (bindings != null) {
for (Binding binding : bindings) {
Offer offer = new Offer();
offer.setCoupon_no(binding.getCoupon_no());
offer.setMac(binding.getMac());
offer.setStartDate(binding.getStartdate());
offer.setEndDate(binding.getEnddate());
long vendorid = binding.getVendor_coupon_id();
Vendor vendor = new Vendor();
vendor.setApk("/rest/downloadfile/" + vendorid + "/getapk");// from
// service
vendor.setArtwork1("/rest/downloadfile/" + vendorid
+ "/getArt1");// from service
vendor.setArtwork2("/rest/downloadfile/" + vendorid
+ "/getArt2");// from service
vendor.setIcon("/rest/downloadfile/" + vendorid + "/getIco");// from
// service
vendor.setRedeem_doc("/rest/downloadfile/" + vendorid
+ "/getHtm");// from service
com.learning.CRUDModel.Vendor localvendor = vendorCRUD
.getVendorById(vendorid);
System.out.println("localvendor.getCountry()"+localvendor.getCountry());
vendor.setCountry(localvendor.getCountry()); // from database
vendor.setDescription(localvendor.getDescription());// from
// database
vendor.setHeading(localvendor.getHeading());// from database
vendor.setName(localvendor.getName());// from database
vendor.setPkg_name(localvendor.getPkg_name());// from database
vendor.setVendor_coupon_id(vendorid);// from database
offer.setVendor(vendor);
list.add(offer);
}
GenericEntity<List<Offer>> entity = new GenericEntity<List<Offer>>(list) {};
Response response = Response.ok(entity).build();
return response;
} else {
Response response = Response.noContent().build();
return response;
}
}
}
产生的错误如下:
Aug 22, 2013 10:07:02 AM com.sun.jersey.spi.container.ContainerResponse mapMappableContainerException
SEVERE: The RuntimeException could not be mapped to a response, re-throwing to the HTTP container
java.lang.NullPointerException
at com.avilyne.rest.resource.VendorOffers.getOffers(VendorOffers.java:71)
at sun.reflect.GeneratedMethodAccessor106.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke(JavaMethodInvokerFactory.java:60)
at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$ResponseOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:205)
at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75)
at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:288)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
at com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:108)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1483)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1414)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1363)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1353)
at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:414)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:537)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:708)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
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:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:947)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1009)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
第 71 行是这样写的:
com.learning.CRUDModel.Vendor localvendor = vendorCRUD
.getVendorById(vendorid);
这里是 vendorCRUD 类:
public class VendorCRUD {
Session session = HibernateUtil.getSession();
public String getVendorApk(String vendor_id){
long id = 0;
try {
id = Long.parseLong(vendor_id);
} catch (NumberFormatException e) {
e.printStackTrace();
}
String apk_path = "not available";
System.out.println("Vendor Id Value:" + vendor_id);
try {
Query query = session.createQuery("from Vendor where Vendor_Coupon_id = :Vendor_Coupon_id ");
query.setParameter("Vendor_Coupon_id",id);
List <Vendor>list = query.list();
if (list.size() > 0) {
apk_path = list.get(0).getApk();
}
} catch (HibernateException ex) {
ex.printStackTrace();
} catch(Exception ex){
ex.printStackTrace();
}
return apk_path;
}
public String getVendorgetArt1(String vendor_id){
long id = 0;
try {
id = Long.parseLong(vendor_id);
} catch (NumberFormatException e) {
e.printStackTrace();
}
String art1_path = "not available";
System.out.println("Vendor Id Value:" + vendor_id);
try {
Query query = session.createQuery("from Vendor where Vendor_Coupon_id = :Vendor_Coupon_id ");
query.setParameter("Vendor_Coupon_id", id);
List <Vendor>list = query.list();
if (list.size() > 0) {
art1_path = list.get(0).getArtwork1();
}
} catch (HibernateException ex) {
ex.printStackTrace();
} catch(Exception ex){
ex.printStackTrace();
}
return art1_path;
}
public String getVendorgetArt2(String vendor_id){
long id = 0;
try {
id = Long.parseLong(vendor_id);
} catch (NumberFormatException e) {
e.printStackTrace();
}
String art1_path = "not available";
System.out.println("Vendor Id Value:" + id);
try {
Query query = session.createQuery("from Vendor where Vendor_Coupon_id = :Vendor_Coupon_id ");
query.setParameter("Vendor_Coupon_id", id);
List <Vendor>list = query.list();
if (list.size() > 0) {
art1_path = list.get(0).getArtwork2();
}
} catch (HibernateException ex) {
ex.printStackTrace();
} catch(Exception ex){
ex.printStackTrace();
}
return art1_path;
}
public String getVendorgetIco(String vendor_id){
long id = 0;
try {
id = Long.parseLong(vendor_id);
} catch (NumberFormatException e) {
e.printStackTrace();
}
String ico_path = "not available";
System.out.println("Vendor Id Value:" + vendor_id);
try {
Query query = session.createQuery("from Vendor where Vendor_Coupon_id = :Vendor_Coupon_id ");
query.setParameter("Vendor_Coupon_id", id);
List <Vendor>list = query.list();
if (list.size() > 0) {
ico_path = list.get(0).getIco();
}
} catch (HibernateException ex) {
ex.printStackTrace();
} catch(Exception ex){
ex.printStackTrace();
}
return ico_path;
}
public String getVendorgetHtm(String vendor_id){
long id = 0;
try {
id = Long.parseLong(vendor_id);
} catch (NumberFormatException e) {
e.printStackTrace();
}
String htm_path = "not available";
System.out.println("Vendor Id Value:" + vendor_id);
try {
Query query = session.createQuery("from Vendor where Vendor_Coupon_id = :Vendor_Coupon_id ");
query.setParameter("Vendor_Coupon_id", id);
List <Vendor>list = query.list();
if (list.size() > 0) {
htm_path = list.get(0).getRedeem_doc();
}
} catch (HibernateException ex) {
ex.printStackTrace();
} catch(Exception ex){
ex.printStackTrace();
}
return htm_path;
}
public List<Vendor> getVendorsForCountry(String country){
List<Vendor> vendors = null;
try {
Query query = session.createQuery("from Vendor where Country = :Country ");
query.setParameter("Country", country);
List <Vendor>list = query.list();
if (list.size() > 0) {
vendors = list;
}
} catch (HibernateException ex) {
ex.printStackTrace();
}catch(Exception ex){
ex.printStackTrace();
}
return vendors;
}
public Vendor getVendorById(long vendorid) {
Vendor uniquevendor = null;
try {
Query query = session.createQuery("from Vendor where Vendor_Coupon_id = :Vendor_Coupon_id ");
query.setParameter("Vendor_Coupon_id", vendorid);
List <Vendor>list = query.list();
if (list.size() > 0) {
uniquevendor = list.get(0);
}
} catch (HibernateException ex) {
ex.printStackTrace();
} catch(Exception ex){
ex.printStackTrace();
}
return uniquevendor;
}
}
最佳答案
如果此行抛出 NPE:
com.learning.CRUDModel.Vendor localvendor = vendorCRUD
.getVendorById(vendorid);
这意味着一件事，只有一件事。抛出 NPE 时，vendorCrud 的值为 null。
不可能说这是怎么发生的。但是，我会注意到 vendorCrud 是可变的，并且与您的 VendorOffers 类在同一包中的任何类都可以访问它。所以可能有很多普通的 Java 代码可以改变它。那么有可能是某些东西正在调用 init() 方法......
根据您的后续评论，我的猜测是您的堆栈中的某些内容未处理过期的 MySQL 连接。默认情况下，MySQL 会断开长时间空闲的连接(我认为默认是 10 小时)。处理此问题的一种方法是将超时更改为非常大的值。为此有一个数据库端配置参数。但是，最好弄清楚这如何/为什么会导致 VendorCRUD 引用……并修复它。
这里的关键是，您需要理解正在发生的事情，方法是将您的 Java 编程和调试技能应用于问题。
关于java - 我必须重新启动我的 tomcat 服务器才能每天早上恢复我的网络服务，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/18375750/