Java JPA EclipseLink数据库异常
尝试使用eclipselink运行一个简单的JPA应用程序。我将persistence.xml存储在src/META-INF/中，并将“eclipselink-2.3.0.jar”、“javax.persistence.jar”和“mysql-connector-java-5.0.4-bin.jar”导入项目（使用Eclipse IDE） Server.javaJava JPA EclipseLink数据库异常,java,eclipse,jpa,eclipselink,connectexception,Java,Eclipse,Jpa,Eclipselink,Connectexception,尝试使用eclipselink运行一个简单的JPA应用程序。我将persistence.xml存储在src/META-INF/中，并将“eclipselink-2.3.0.jar”、“javax.persistence.jar”和“mysql-connector-java-5.0.4-bin.jar”导入项目（使用Eclipse IDE） Server.java public class Server { private EntityManagerFactory emFactory; Serv
public class Server {
private EntityManagerFactory emFactory;
Server() {
super();
emFactory = Persistence.createEntityManagerFactory("test");
}
public void newAccount(String name){
EntityManager em = null;
try {
em = beginTransaction();
List<Account> existingAccounts = em.createNamedQuery("findAccountWithName", Account.class).setParameter("ownerName", name).getResultList();
if (existingAccounts.size() != 0) {
System.out.println("already exists"); return;
}
Account account = new Account(name, 5000);
em.persist(account);
System.out.println("Account " + name + " created");
} finally { commitTransaction(em); }
}
private EntityManager beginTransaction() {
EntityManager em = emFactory.createEntityManager();
EntityTransaction transaction = em.getTransaction();
transaction.begin();
return em;
}
private void commitTransaction(EntityManager em) { em.getTransaction().commit(); }
public static void main(String[] args) {
Server k = new Server();
k.newAccount("Bob");
}
}
<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
version="2.0">
<persistence-unit name="test" transaction-type="RESOURCE_LOCAL">
<provider>
org.eclipse.persistence.jpa.PersistenceProvider
</provider>
<class>Account</class>
<properties>
<property name="eclipselink.ddl-generation" value="drop-and-create-tables"/>
<property name="eclipselink.ddl-generation.output-mode" value="database"/>
<property name="eclipselink.logging.level" value="INFO"/>
<property name="javax.persistence.jdbc.password" value="javajava"/>
<property name="javax.persistence.jdbc.user" value="root"/>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost/bank"/>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
</properties>
</persistence-unit>
</persistence>
org.eclipse.persistence.jpa.PersistenceProvider
账户
[EL Info]: 2013-12-19 16:32:36.467--ServerSession(1685940940)--EclipseLink, version: Eclipse Persistence Services - 2.3.0.v20110604-r9504
[EL Severe]: 2013-12-19 16:32:40.568--ServerSession(1685940940)--Local Exception Stack:
Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.3.0.v20110604-r9504): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:
** BEGIN NESTED EXCEPTION **
java.net.SocketException
MESSAGE: java.net.ConnectException: Connection refused: connect
STACKTRACE:
java.net.SocketException: java.net.ConnectException: Connection refused: connect
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:156)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:276)
at com.mysql.jdbc.Connection.createNewIO(Connection.java:2666)
at com.mysql.jdbc.Connection.<init>(Connection.java:1531)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:266)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at org.eclipse.persistence.sessions.DefaultConnector.connect(DefaultConnector.java:98)
at org.eclipse.persistence.sessions.DatasourceLogin.connectToDatasource(DatasourceLogin.java:162)
at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.loginAndDetectDatasource(DatabaseSessionImpl.java:582)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryProvider.login(EntityManagerFactoryProvider.java:206)
at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:472)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.getDatabaseSession(EntityManagerFactoryDelegate.java:188)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.createEntityManagerImpl(EntityManagerFactoryDelegate.java:277)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManagerImpl(EntityManagerFactoryImpl.java:290)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:268)
at Server.beginTransaction(Server.java:84)
at Server.newAccount(Server.java:38)
at Server.main(Server.java:30)
** END NESTED EXCEPTION **
Last packet sent to the server was 18 ms ago.
Error Code: 0
at org.eclipse.persistence.exceptions.DatabaseException.sqlException(DatabaseException.java:324)
at org.eclipse.persistence.exceptions.DatabaseException.sqlException(DatabaseException.java:319)
at org.eclipse.persistence.sessions.DefaultConnector.connect(DefaultConnector.java:138)
at org.eclipse.persistence.sessions.DatasourceLogin.connectToDatasource(DatasourceLogin.java:162)
at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.loginAndDetectDatasource(DatabaseSessionImpl.java:582)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryProvider.login(EntityManagerFactoryProvider.java:206)
at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:472)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.getDatabaseSession(EntityManagerFactoryDelegate.java:188)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.createEntityManagerImpl(EntityManagerFactoryDelegate.java:277)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManagerImpl(EntityManagerFactoryImpl.java:290)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:268)
at Server.beginTransaction(Server.java:84)
at Server.newAccount(Server.java:38)
at Server.main(Server.java:30)
Caused by: com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:
** BEGIN NESTED EXCEPTION **
java.net.SocketException
MESSAGE: java.net.ConnectException: Connection refused: connect
STACKTRACE:
java.net.SocketException: java.net.ConnectException: Connection refused: connect
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:156)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:276)
at com.mysql.jdbc.Connection.createNewIO(Connection.java:2666)
at com.mysql.jdbc.Connection.<init>(Connection.java:1531)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:266)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at org.eclipse.persistence.sessions.DefaultConnector.connect(DefaultConnector.java:98)
at org.eclipse.persistence.sessions.DatasourceLogin.connectToDatasource(DatasourceLogin.java:162)
at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.loginAndDetectDatasource(DatabaseSessionImpl.java:582)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryProvider.login(EntityManagerFactoryProvider.java:206)
at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:472)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.getDatabaseSession(EntityManagerFactoryDelegate.java:188)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.createEntityManagerImpl(EntityManagerFactoryDelegate.java:277)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManagerImpl(EntityManagerFactoryImpl.java:290)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:268)
at Server.beginTransaction(Server.java:84)
at Server.newAccount(Server.java:38)
at Server.main(Server.java:30)
** END NESTED EXCEPTION **
Last packet sent to the server was 18 ms ago.
at com.mysql.jdbc.Connection.createNewIO(Connection.java:2741)
at com.mysql.jdbc.Connection.<init>(Connection.java:1531)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:266)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at org.eclipse.persistence.sessions.DefaultConnector.connect(DefaultConnector.java:98)
... 11 more
Exception in thread "main" java.lang.NullPointerException
at Server.commitTransaction(Server.java:90)
at Server.newAccount(Server.java:47)
at Server.main(Server.java:30)
[EL-Info]：2013-12-19 16:32:36.467——服务器会话（1685940940）——EclipseLink，版本：Eclipse持久性服务-2.3.0.v20110604-r9504
[EL Severe]：2013-12-19 16:32:40.568——服务器会话（1685940940）——本地异常堆栈：
异常[EclipseLink-4002]（Eclipse持久性服务-2.3.0.v20110604-r9504）：org.Eclipse.Persistence.exceptions.DatabaseException
内部异常：com.mysql.jdbc.CommunicationsException:由于基础异常导致的通信链路故障：
**开始嵌套异常**
java.net.SocketException
消息：java.net.ConnectException:连接被拒绝：连接
堆栈跟踪：
java.net.SocketException:java.net.ConnectException:连接被拒绝：连接
位于com.mysql.jdbc.StandardSocketFactory.connect（StandardSocketFactory.java:156）
在com.mysql.jdbc.MysqlIO上（MysqlIO.java:276）
在com.mysql.jdbc.Connection.createNewIO上（Connection.java:2666）
位于com.mysql.jdbc.Connection（Connection.java:1531）
位于com.mysql.jdbc.NonRegisteringDriver.connect（NonRegisteringDriver.java:266）
位于java.sql.DriverManager.getConnection（未知源）
位于java.sql.DriverManager.getConnection（未知源）
位于org.eclipse.persistence.sessions.DefaultConnector.connect（DefaultConnector.java:98）
位于org.eclipse.persistence.sessions.DatasourceLogin.connectToDatasource（DatasourceLogin.java:162）
位于org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.loginandetectdatasource（DatabaseSessionImpl.java:582）
位于org.eclipse.persistence.internal.jpa.EntityManagerFactoryProvider.login（EntityManagerFactoryProvider.java:206）
位于org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy（EntityManagerSetupImpl.java:472）
位于org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.getDatabaseSession（EntityManagerFactoryDelegate.java:188）
位于org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.createEntityManagerImpl（EntityManagerFactoryDelegate.java:277）
位于org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManagerImpl（EntityManagerFactoryImpl.java:290）
位于org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManager（EntityManagerFactoryImpl.java:268）
在Server.beginTransaction（Server.java:84）
在Server.newAccount（Server.java:38）
位于Server.main（Server.java:30）
**结束嵌套异常**
发送到服务器的最后一个数据包是18毫秒前。
错误代码：0
位于org.eclipse.persistence.exceptions.DatabaseException.sqlException（DatabaseException.java:324）
位于org.eclipse.persistence.exceptions.DatabaseException.sqlException（DatabaseException.java:319）
位于org.eclipse.persistence.sessions.DefaultConnector.connect（DefaultConnector.java:138）
位于org.eclipse.persistence.sessions.DatasourceLogin.connectToDatasource（DatasourceLogin.java:162）
位于org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.loginandetectdatasource（DatabaseSessionImpl.java:582）
位于org.eclipse.persistence.internal.jpa.EntityManagerFactoryProvider.login（EntityManagerFactoryProvider.java:206）
位于org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy（EntityManagerSetupImpl.java:472）
位于org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.getDatabaseSession（EntityManagerFactoryDelegate.java:188）
位于org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.createEntityManagerImpl（EntityManagerFactoryDelegate.java:277）
位于org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManagerImpl（EntityManagerFactoryImpl.java:290）
位于org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManager（EntityManagerFactoryImpl.java:268）
在Server.beginTransaction（Server.java:84）
在Server.newAccount（Server.java:38）
位于Server.main（Server.java:30）
原因：com.mysql.jdbc.CommunicationsException:由于基础异常导致的通信链路故障：
**开始嵌套异常**
java.net.SocketException
消息：java.net.ConnectException:连接被拒绝：连接
堆栈跟踪：
java.net.SocketException:java.net.ConnectException:连接被拒绝：连接
位于com.mysql.jdbc.StandardSocketFactory.connect（StandardSocketFactory.java:156）
在com.mysql.jdbc.MysqlIO上（MysqlIO.java:276）
在com.mysql.jdbc.Connection.createNewIO上（Connection.java:2666）
位于com.mysql.jdbc.Connection（Connection.java:1531）
位于com.mysql.jdbc.NonRegisteringDriver.connect（NonRegisteringDriver.java:266）
位于java.sql.DriverManager.getConnection（未知源）
位于java.sql.DriverManager.getConnection（未知源）
位于org.eclipse.persistence.sessions.DefaultConnector.connect（DefaultConnector.java:98）
位于org.eclipse.persistence.sessions.DatasourceLogin.connectToDatasource（DatasourceLogin.java:162）
位于org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.loginandetectdatasource（DatabaseSessionImpl.java:582）
位于org.eclipse.persistence.internal.jpa.EntityManagerFactoryProvider.login（EntityManagerFactoryProvider.java:206）
位于org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy（EntityManagerSetupImpl.java:472）
位于org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.getDatabaseSession（EntityManagerFactoryDelegate.java:188）
位于org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.createEntityManagerImpl（EntityManagerFactoryDelegate.java:277）
在org.eclipse.persistence.internal上。
[EL Info]: 2013-12-19 16:32:36.467--ServerSession(1685940940)--EclipseLink, version: Eclipse Persistence Services - 2.3.0.v20110604-r9504
[EL Severe]: 2013-12-19 16:32:40.568--ServerSession(1685940940)--Local Exception Stack:
Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.3.0.v20110604-r9504): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:
** BEGIN NESTED EXCEPTION **
java.net.SocketException
MESSAGE: java.net.ConnectException: Connection refused: connect
STACKTRACE:
java.net.SocketException: java.net.ConnectException: Connection refused: connect
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:156)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:276)
at com.mysql.jdbc.Connection.createNewIO(Connection.java:2666)
at com.mysql.jdbc.Connection.<init>(Connection.java:1531)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:266)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at org.eclipse.persistence.sessions.DefaultConnector.connect(DefaultConnector.java:98)
at org.eclipse.persistence.sessions.DatasourceLogin.connectToDatasource(DatasourceLogin.java:162)
at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.loginAndDetectDatasource(DatabaseSessionImpl.java:582)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryProvider.login(EntityManagerFactoryProvider.java:206)
at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:472)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.getDatabaseSession(EntityManagerFactoryDelegate.java:188)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.createEntityManagerImpl(EntityManagerFactoryDelegate.java:277)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManagerImpl(EntityManagerFactoryImpl.java:290)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:268)
at Server.beginTransaction(Server.java:84)
at Server.newAccount(Server.java:38)
at Server.main(Server.java:30)
** END NESTED EXCEPTION **
Last packet sent to the server was 18 ms ago.
Error Code: 0
at org.eclipse.persistence.exceptions.DatabaseException.sqlException(DatabaseException.java:324)
at org.eclipse.persistence.exceptions.DatabaseException.sqlException(DatabaseException.java:319)
at org.eclipse.persistence.sessions.DefaultConnector.connect(DefaultConnector.java:138)
at org.eclipse.persistence.sessions.DatasourceLogin.connectToDatasource(DatasourceLogin.java:162)
at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.loginAndDetectDatasource(DatabaseSessionImpl.java:582)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryProvider.login(EntityManagerFactoryProvider.java:206)
at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:472)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.getDatabaseSession(EntityManagerFactoryDelegate.java:188)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.createEntityManagerImpl(EntityManagerFactoryDelegate.java:277)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManagerImpl(EntityManagerFactoryImpl.java:290)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:268)
at Server.beginTransaction(Server.java:84)
at Server.newAccount(Server.java:38)
at Server.main(Server.java:30)
Caused by: com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:
** BEGIN NESTED EXCEPTION **
java.net.SocketException
MESSAGE: java.net.ConnectException: Connection refused: connect
STACKTRACE:
java.net.SocketException: java.net.ConnectException: Connection refused: connect
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:156)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:276)
at com.mysql.jdbc.Connection.createNewIO(Connection.java:2666)
at com.mysql.jdbc.Connection.<init>(Connection.java:1531)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:266)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at org.eclipse.persistence.sessions.DefaultConnector.connect(DefaultConnector.java:98)
at org.eclipse.persistence.sessions.DatasourceLogin.connectToDatasource(DatasourceLogin.java:162)
at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.loginAndDetectDatasource(DatabaseSessionImpl.java:582)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryProvider.login(EntityManagerFactoryProvider.java:206)
at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:472)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.getDatabaseSession(EntityManagerFactoryDelegate.java:188)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.createEntityManagerImpl(EntityManagerFactoryDelegate.java:277)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManagerImpl(EntityManagerFactoryImpl.java:290)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:268)
at Server.beginTransaction(Server.java:84)
at Server.newAccount(Server.java:38)
at Server.main(Server.java:30)
** END NESTED EXCEPTION **
Last packet sent to the server was 18 ms ago.
at com.mysql.jdbc.Connection.createNewIO(Connection.java:2741)
at com.mysql.jdbc.Connection.<init>(Connection.java:1531)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:266)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at org.eclipse.persistence.sessions.DefaultConnector.connect(DefaultConnector.java:98)
... 11 more
Exception in thread "main" java.lang.NullPointerException
at Server.commitTransaction(Server.java:90)
at Server.newAccount(Server.java:47)
at Server.main(Server.java:30)