WARN SqlExceptionHelper: 143 - SQL Lỗi: 0, SQLState: 08S01- SqlExceptionHelper: 144 - Truyền thông liên kết thất bại

Question

Tôi có vấn đề với Hibernate (ngủ đông -core-4.1.9.Final.jar)

Khi tôi thử nghiệm ngủ đông trong vòng lặp for tất cả làm việc tốt:

for(int i=0;i<1500;i++){ 

    UserDAO.getInstance.getById(1); 
} 

Khi tôi thêm Thread.sleep() trong vòng lặp for

for(int i=0;i<1500;i++){ 


     UserDAO.getInstance.getById(1); 
     Thread.sleep(60000); 
} 

Sau 1 phút tôi nhận được ngoại lệ:

00:20:06,447 WARN SqlExceptionHelper:143 - SQL Error: 0, SQLState: 08S01 
00:20:06,448 ERROR SqlExceptionHelper:144 - Communications link failure 

The last packet successfully received from the server was 120,017 milliseconds ago. The last packet sent successfully to the server was 9 milliseconds ago. 
Exception in thread "main" org.hibernate.exception.JDBCConnectionException: Communications link failure 

The last packet successfully received from the server was 120,017 milliseconds ago. The last packet sent successfully to the server was 9 milliseconds ago. 
    at org.hibernate.exception.internal.SQLStateConversionDelegate.convert(SQLStateConversionDelegate.java:131) 
    at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:49) 
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:125) 
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:110) 
    at org.hibernate.engine.jdbc.internal.proxy.AbstractStatementProxyHandler.continueInvocation(AbstractStatementProxyHandler.java:129) 
    at org.hibernate.engine.jdbc.internal.proxy.AbstractProxyHandler.invoke(AbstractProxyHandler.java:81) 
    at sun.proxy.$Proxy11.executeQuery(Unknown Source) 
    at org.hibernate.loader.Loader.getResultSet(Loader.java:2031) 
    at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1832) 
    at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1811) 
    at org.hibernate.loader.Loader.doQuery(Loader.java:899) 
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:341) 
    at org.hibernate.loader.Loader.doList(Loader.java:2516) 
    at org.hibernate.loader.Loader.doList(Loader.java:2502) 
    at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2332) 
    at org.hibernate.loader.Loader.list(Loader.java:2327) 
    at org.hibernate.loader.criteria.CriteriaLoader.list(CriteriaLoader.java:124) 
    at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1621) 
    at org.hibernate.internal.CriteriaImpl.list(CriteriaImpl.java:374) 
    at org.hibernate.internal.CriteriaImpl.uniqueResult(CriteriaImpl.java:396) 
    at com.fit.utilities.BaseDAO.getById(BaseDAO.java:35) 
    at com.fit.test.Testiranje.main(Testiranje.java:51) 
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure 

The last packet successfully received from the server was 120,017 milliseconds ago. The last packet sent successfully to the server was 9 milliseconds ago. 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) 
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) 
    at java.lang.reflect.Constructor.newInstance(Unknown Source) 
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) 
    at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1121) 
    at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3603) 
    at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3492) 
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4043) 
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2503) 
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2664) 
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2815) 
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2155) 
    at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:2322) 
    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.hibernate.engine.jdbc.internal.proxy.AbstractStatementProxyHandler.continueInvocation(AbstractStatementProxyHandler.java:122) 
    ... 17 more 
Caused by: java.io.EOFException: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost. 
    at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:3052) 
    at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3503) 
    ... 29 more 

Đây là hibernate.cfg.xml tôi

<?xml version='1.0' encoding='UTF-8'?> 
<!DOCTYPE hibernate-configuration PUBLIC 
      "-//Hibernate/Hibernate Configuration DTD 3.0//EN" 
      "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"> 

<hibernate-configuration> 

    <session-factory> 


     <property name="connection.driver_class">com.mysql.jdbc.Driver</property> 
      <property name="connection.url">jdbc:mysql://xxxxxx:3306/xxxx</property> 
      <property name="connection.username">xxxx</property> 
      <property name="connection.password">xxxx</property> 
      <property name="dialect">org.hibernate.dialect.MySQLDialect</property> 
      <property name="hibernate.hbm2ddl.auto">update</property> 
      <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property> 
      <property name="show_sql">false</property> 
      <property name="hibernate.connection.pool_size">1</property> 





     <!-- Mapping files --> 
     <mapping class="com.xxx.model.xxxxx" /> 
     <mapping class="com.xxx.model.xxxxx" /> 
     <mapping class="com.xxx.model.xxxxx" /> 

    </session-factory> 
</hibernate-configuration> 

Làm thế nào để giải quyết vấn đề này?

CẬP NHẬT: Tôi nghĩ rằng tôi giải quyết được sự cố.

tôi đặt này trong hibernate.cfg.xml

<!-- configuration pool via c3p0--> 
<property name="c3p0.acquire_increment">1</property> 
<property name="c3p0.idle_test_period">100</property> <!-- seconds --> 
<property name="c3p0.max_size">100</property> 
<property name="c3p0.max_statements">0</property> 
<property name="c3p0.min_size">10</property> 
<property name="c3p0.timeout">100</property> <!-- seconds --> 

Answer 1

Lỗi này xảy ra bởi vì có giá trị nhỏ của biến time_out trên máy chủ mysql. Thực tế, vì kết nối jdbc hết hạn.

Trong trường hợp time_out của tôi được đặt trong 1 phút. Sử dụng cơ chế tổng hợp C3PO, chúng tôi có thể tối ưu hóa kết nối JDBC.

Bạn có thể tải libs C3P0 từ http://sourceforge.net/projects/c3p0/

tôi sử dụng ngủ đông 3,0.

Đây là mã:

hibernate.cfg.xml

<?xml version='1.0' encoding='UTF-8'?> 
<!DOCTYPE hibernate-configuration PUBLIC 
      "-//Hibernate/Hibernate Configuration DTD 3.0//EN" 
      "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"> 

<hibernate-configuration> 

    <session-factory> 

     <property name="connection.driver_class">com.mysql.jdbc.Driver</property> 
      <property name="connection.url">jdbc:mysql://databasehost:3306/databasename</property> 
      <property name="connection.username">user</property> 
      <property name="connection.password">psw</property> 
      <property name="dialect">org.hibernate.dialect.MySQLDialect</property> 
      <property name="hibernate.hbm2ddl.auto">update</property> 

      <property name="show_sql">false</property> 

    <!-- 
      hibernate c3p0 settings 
     --> 

     <property name="connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</property> 
     <property name="hibernate.c3p0.acquire_increment">3</property> 
     <property name="hibernate.c3p0.idle_test_period">10</property> 
     <property name="hibernate.c3p0.min_size">5</property> 
     <property name="hibernate.c3p0.max_size">75</property> 
     <property name="hibernate.c3p0.max_statements">10</property> 
     <property name="hibernate.c3p0.timeout">50</property> 
     <property name="hibernate.c3p0.preferredTestQuery">select 1</property> 
     <property name="hibernate.c3p0.testConnectionOnCheckout">true</property> 

     <!-- Mapping files --> 
     <mapping class="xxx.xxx.xxx.xxx" /> 
     <mapping class="xxx.xxx.xxx.xxx" /> 
     <mapping class="xxx.xxx.xxx.xxx" /> 
     <mapping class="xxx.xxx.xxx.xxx" /> 


    </session-factory> 
</hibernate-configuration> 

PersistenceManager.java

import java.io.PrintStream; 
import org.hibernate.SessionFactory; 
import org.hibernate.cfg.AnnotationConfiguration; 
import org.hibernate.cfg.Configuration; 

public class PersistenceManager 
{ 
    private static SessionFactory sessionFactory = null; 

    private static PersistenceManager singleton = null; 

    public static PersistenceManager getInstance() 
    { 
    if (singleton == null) 
    { 
     singleton = new PersistenceManager(); 
    } 

    return singleton; 
    } 

    public SessionFactory getSessionFactory() 
    { 
    if (sessionFactory == null) 
     createSessionFactory(); 
    return sessionFactory; 
    } 

    protected void createSessionFactory() 
    {  
    sessionFactory = new AnnotationConfiguration().configure() 
     .buildSessionFactory(); 
    } 

    public void destroySessionFactory() 
    { 
    if (sessionFactory != null) 
    { 
     sessionFactory.close(); 
     sessionFactory = null; 
    } 
    } 
} 

Ví dụ 1:

import org.hibernate.HibernateException; 
import org.hibernate.Query; 
import org.hibernate.Session; 

public Users Login(String username, String password) 
    { 
    Session session = null; 
    try 
    { 
     String hql = "select u from Users u where u.username like :p1 and u.password like :p2"; 
     session = PersistenceManager.getInstance().getSessionFactory().openSession(); 

     Query q = session.createQuery(hql) 
     .setParameter("p1", username) 
     .setParameter("p2", password); 

     if (q.list().size() == 0) 
     { 
     session.close(); 
     return new Users(); 
     } 

     Users user = (Users)q.list().get(0); 
     session.close(); 
     return user; 
    } 
    catch (Exception e) 
    { 
     session.close(); 

    } 
    } 

Ví dụ 2:

import org.hibernate.HibernateException; 
import org.hibernate.Query; 
import org.hibernate.Session; 
public String Registration(Users u) { 

    Session session = null; 
    try 
    { 
     String hql = "select u from Users u where u.username like :p1"; 

     session = PersistenceManager.getInstance().getSessionFactory().openSession(); 

     Query q = session.createQuery(hql).setParameter("p1", u.getUsername()); 

     if (q.list().size() == 0) 
     { 
     session.beginTransaction(); 
     session.persist(u); 
     session.getTransaction().commit(); 
     session.close(); 
     return new Boolean(true).toString(); 
     } 

     session.close(); 

     return new Boolean(false).toString(); 
    } 
    catch (Exception e) 
    { 
     return e.toString(); 
    } 
    } 

Answer 2

tôi đã cùng một vấn đề chỉ vì tôi quên quấn đang ngủ đông của tôi trong một giao dịch. Dường như kết nối tới DB không được đóng cho đến khi bạn thực hiện giao dịch. Dưới đây là ví dụ hợp lệ:

Session session = HibernateUtils.getSession(); 
Transaction tx = session.beginTransaction(); 
Category cat = null; 

try{ 
    cat = (Category)session.get(Category.class, 1); 
    tx.commit(); 
}catch(Exception ex){ 
    tx.rollback(); 
}finally{   
    session.close(); 
} 

return cat;