MySQL 警告 SqlExceptionHelper:143 - SQL 错误: 0, SQLState: 08S01- SqlExceptionHelper:144 - 通信链接失败
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时间：2020-08-31 17:09:21 来源:igfitidea点击:
WARN SqlExceptionHelper:143 - SQL Error: 0, SQLState: 08S01- SqlExceptionHelper:144 - Communications link failure
提问by Haris D.
I have problem with Hibernate (hibernate-core-4.1.9.Final.jar)
我有 Hibernate 问题（hibernate-core-4.1.9.Final.jar）
When i testing hibernate in for loop all working fine:
当我在 for 循环中测试休眠时，一切正常：
for(int i=0;i<1500;i++){
UserDAO.getInstance.getById(1);
}
When i add Thread.sleep()in for loop
当我在 for 循环中添加Thread.sleep()
for(int i=0;i<1500;i++){
UserDAO.getInstance.getById(1);
Thread.sleep(60000);
}
After 1 minute i get exception :
1分钟后我得到异常：
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
Here is my hibernate.cfg.xml
这是我的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://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>
How to resolve this problem?
如何解决这个问题？
UPDATE:I think i solve problem.
更新：我想我解决了问题。
I put this in hibernate.cfg.xml
我把它放在 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 -->
回答by Haris D.
The problem was happening because of small value time_outvar on mysql server.
问题发生是因为time_outmysql 服务器上的 var值很小。
In my situation time_out was set to 1 minute. Using C3PO pooling mechanism we can optimize JDBC.
在我的情况下，time_out 设置为 1 分钟。使用 C3PO 池化机制我们可以优化 JDBC。
Download c3p0-> http://sourceforge.net/projects/c3p0/
下载c3p0-> http://sourceforge.net/projects/c3p0/
I'm using hibernate 3.0.
我正在使用休眠 3.0。
hibernate.cfg.xml
休眠文件.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
持久化管理器
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;
}
}
}
Example 1:
示例 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();
}
}
Example 2:
示例 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();
}
}
回答by pubsy
I had the same issue just because I forgot to wrap my hibernate code in a transaction. Apparently the connection to DB is not closed until you commit a transaction. Here is a valid example:
我遇到了同样的问题，因为我忘记在事务中包装我的休眠代码。显然，在您提交事务之前，与 DB 的连接不会关闭。这是一个有效的例子：
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;
