我之前的项目是用hibernate 4.3做的，并没有任何问题。这次我正在使用hibernate 5.2。当我收到此错误时，我正面临问题：
ERROR: Collection leak detected: there are 1 unclosed connections upon shutting down pool
经过调查，我注意到save hibernate试图打开2个连接。为什么？我一直在使用这些设置，但之前从未遇到过问题：
<property name="hibernate.connection.pool_size">1</property>
MainApp.java：
package home.accounting;
import org.hibernate.SessionFactory;
import org.hibernate.boot.MetadataSources;
import org.hibernate.boot.registry.StandardServiceRegistry;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import home.accounting.DA.LanguagesDA;
import home.accounting.model.Languages;
import javafx.application.Application;
import javafx.stage.Stage;
public class MainApp extends Application {
private SessionFactory sessionFactory;
@Override
public void start(Stage primaryStage) {
LanguagesDA.setMainApp(this);
final StandardServiceRegistry registry = new StandardServiceRegistryBuilder()
.configure() // configures settings from hibernate.cfg.xml
.build();
try {
sessionFactory = new MetadataSources( registry ).buildMetadata().buildSessionFactory();
LanguagesDA.save(new Languages("english","en"));
}
catch (Exception e) {
// The registry would be destroyed by the SessionFactory, but we had trouble building the SessionFactory
// so destroy it manually.
StandardServiceRegistryBuilder.destroy( registry );
}
}
/**
* Initialises the root layout.
*/
public void initRootLayout() {
}
public static void main(String[] args) {
launch(args);
}
public SessionFactory getSessionFactory(){
return sessionFactory;
}
@Override
public void stop() throws Exception {
sessionFactory.close();
}
}
LanguagesDA.java ：
package home.accounting.DA;
import org.hibernate.Session;
import org.hibernate.Transaction;
import home.accounting.MainApp;
import home.accounting.model.Languages;
public class LanguagesDA {
private static MainApp mainApp;
public static void save(Languages language) {
Session sess = mainApp.getSessionFactory().openSession();
System.out.println("Session opened!");
Transaction tx = null;
try {
tx = sess.beginTransaction();
sess.save(language);
tx.commit();
}
catch (Exception e) {
if (tx!=null) tx.rollback();
System.out.println(e);
throw e;
}
finally {
sess.close();
System.out.println("Session closed!");
}
}
public static void setMainApp(MainApp app) {
mainApp = app;
}
}
Languages.java ：
package home.accounting.model;
import javax.persistence.*;
@Entity
@Table(name="languages")
public class Languages {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name="language_id")
private int id;
@Column(name="language_name")
private String name;
@Column(name="language_code")
private String code;
public Languages(){}
public Languages(String name, String code){
this.name = name;
this.code = code;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getCode() {
return code;
}
public void setCode(String code) {
this.code = code;
}
}
hibernate.cfg.xml中：
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<!-- Database connection settings -->
<property name="hibernate.connection.driver_class">org.sqlite.JDBC</property>
<property name="hibernate.connection.url">jdbc:sqlite:src/home/accounting/DB/Accounting.sqlite</property>
<property name="hibernate.connection.username"></property>
<property name="hibernate.connection.password"></property>
<!-- JDBC connection pool (use the built-in) -->
<property name="hibernate.connection.pool_size">1</property>
<!-- SQL dialect -->
<property name="hibernate.dialect">org.hibernate.dialect.SQLiteDialect</property>
<!-- Disable the second-level cache -->
<property name="hibernate.cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>
<!-- Echo all executed SQL to stdout -->
<property name="hibernate.show_sql">true</property>
<property name="hibernate.format_sql">false</property>
<property name="hibernate.connection.release_mode">on_close</property>
<!-- Drop and re-create the database schema on startup -->
<property name="hibernate.hbm2ddl.auto">none</property>
<!-- Names the annotated entity class -->
<mapping class="home.accounting.model.Languages"/>
</session-factory>
</hibernate-configuration>
SQLiteDialect.java ：
/*
* The author disclaims copyright to this source code. In place of
* a legal notice, here is a blessing:
*
* May you do good and not evil.
* May you find forgiveness for yourself and forgive others.
* May you share freely, never taking more than you give.
*
*/
package org.hibernate.dialect;
import java.sql.SQLException;
import java.sql.Types;
import org.hibernate.JDBCException;
import org.hibernate.ScrollMode;
import org.hibernate.dialect.function.AbstractAnsiTrimEmulationFunction;
import org.hibernate.dialect.function.NoArgSQLFunction;
import org.hibernate.dialect.function.SQLFunction;
import org.hibernate.dialect.function.SQLFunctionTemplate;
import org.hibernate.dialect.function.StandardSQLFunction;
import org.hibernate.dialect.function.VarArgsSQLFunction;
import org.hibernate.dialect.identity.IdentityColumnSupport;
import org.hibernate.dialect.identity.SQLiteDialectIdentityColumnSupport;
import org.hibernate.dialect.pagination.AbstractLimitHandler;
import org.hibernate.dialect.pagination.LimitHandler;
import org.hibernate.dialect.pagination.LimitHelper;
import org.hibernate.dialect.unique.DefaultUniqueDelegate;
import org.hibernate.dialect.unique.UniqueDelegate;
import org.hibernate.engine.spi.RowSelection;
import org.hibernate.exception.DataException;
import org.hibernate.exception.JDBCConnectionException;
import org.hibernate.exception.LockAcquisitionException;
import org.hibernate.exception.spi.SQLExceptionConversionDelegate;
import org.hibernate.exception.spi.TemplatedViolatedConstraintNameExtracter;
import org.hibernate.exception.spi.ViolatedConstraintNameExtracter;
import org.hibernate.internal.util.JdbcExceptionHelper;
import org.hibernate.mapping.Column;
import org.hibernate.type.StandardBasicTypes;
/**
* An SQL dialect for SQLite 3.
*/
public class SQLiteDialect extends Dialect {
private final UniqueDelegate uniqueDelegate;
public SQLiteDialect() {
registerColumnType( Types.BIT, "boolean" );
//registerColumnType(Types.FLOAT, "float");
//registerColumnType(Types.DOUBLE, "double");
registerColumnType( Types.DECIMAL, "decimal" );
registerColumnType( Types.CHAR, "char" );
registerColumnType( Types.LONGVARCHAR, "longvarchar" );
registerColumnType( Types.TIMESTAMP, "datetime" );
registerColumnType( Types.BINARY, "blob" );
registerColumnType( Types.VARBINARY, "blob" );
registerColumnType( Types.LONGVARBINARY, "blob" );
registerFunction( "concat", new VarArgsSQLFunction( StandardBasicTypes.STRING, "", "||", "" ) );
registerFunction( "mod", new SQLFunctionTemplate( StandardBasicTypes.INTEGER, "?1 % ?2" ) );
registerFunction( "quote", new StandardSQLFunction( "quote", StandardBasicTypes.STRING ) );
registerFunction( "random", new NoArgSQLFunction( "random", StandardBasicTypes.INTEGER ) );
registerFunction( "round", new StandardSQLFunction( "round" ) );
registerFunction( "substr", new StandardSQLFunction( "substr", StandardBasicTypes.STRING ) );
registerFunction( "trim", new AbstractAnsiTrimEmulationFunction() {
protected SQLFunction resolveBothSpaceTrimFunction() {
return new SQLFunctionTemplate( StandardBasicTypes.STRING, "trim(?1)" );
}
protected SQLFunction resolveBothSpaceTrimFromFunction() {
return new SQLFunctionTemplate( StandardBasicTypes.STRING, "trim(?2)" );
}
protected SQLFunction resolveLeadingSpaceTrimFunction() {
return new SQLFunctionTemplate( StandardBasicTypes.STRING, "ltrim(?1)" );
}
protected SQLFunction resolveTrailingSpaceTrimFunction() {
return new SQLFunctionTemplate( StandardBasicTypes.STRING, "rtrim(?1)" );
}
protected SQLFunction resolveBothTrimFunction() {
return new SQLFunctionTemplate( StandardBasicTypes.STRING, "trim(?1, ?2)" );
}
protected SQLFunction resolveLeadingTrimFunction() {
return new SQLFunctionTemplate( StandardBasicTypes.STRING, "ltrim(?1, ?2)" );
}
protected SQLFunction resolveTrailingTrimFunction() {
return new SQLFunctionTemplate( StandardBasicTypes.STRING, "rtrim(?1, ?2)" );
}
} );
uniqueDelegate = new SQLiteUniqueDelegate( this );
}
// database type mapping support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@Override
public String getCastTypeName(int code) {
// FIXME
return super.getCastTypeName( code );
}
// IDENTITY support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
private static final SQLiteDialectIdentityColumnSupport IDENTITY_COLUMN_SUPPORT = new SQLiteDialectIdentityColumnSupport();
@Override
public IdentityColumnSupport getIdentityColumnSupport() {
return IDENTITY_COLUMN_SUPPORT;
}
// limit/offset support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
private static final AbstractLimitHandler LIMIT_HANDLER = new AbstractLimitHandler() {
@Override
public String processSql(String sql, RowSelection selection) {
final boolean hasOffset = LimitHelper.hasFirstRow( selection );
return sql + (hasOffset ? " limit ? offset ?" : " limit ?");
}
@Override
public boolean supportsLimit() {
return true;
}
@Override
public boolean bindLimitParametersInReverseOrder() {
return true;
}
};
@Override
public LimitHandler getLimitHandler() {
return LIMIT_HANDLER;
}
// lock acquisition support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@Override
public boolean supportsLockTimeouts() {
// may be http://sqlite.org/c3ref/db_mutex.html ?
return false;
}
@Override
public String getForUpdateString() {
return "";
}
@Override
public boolean supportsOuterJoinForUpdate() {
return false;
}
/*
@Override
public boolean dropTemporaryTableAfterUse() {
return true; // temporary tables are only dropped when the connection is closed. If the connection is pooled...
}
*/
// current timestamp support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@Override
public boolean supportsCurrentTimestampSelection() {
return true;
}
public boolean isCurrentTimestampSelectStringCallable() {
return false;
}
@Override
public String getCurrentTimestampSelectString() {
return "select current_timestamp";
}
// SQLException support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
private static final int SQLITE_BUSY = 5;
private static final int SQLITE_LOCKED = 6;
private static final int SQLITE_IOERR = 10;
private static final int SQLITE_CORRUPT = 11;
private static final int SQLITE_NOTFOUND = 12;
private static final int SQLITE_FULL = 13;
private static final int SQLITE_CANTOPEN = 14;
private static final int SQLITE_PROTOCOL = 15;
private static final int SQLITE_TOOBIG = 18;
private static final int SQLITE_CONSTRAINT = 19;
private static final int SQLITE_MISMATCH = 20;
private static final int SQLITE_NOTADB = 26;
@Override
public SQLExceptionConversionDelegate buildSQLExceptionConversionDelegate() {
return new SQLExceptionConversionDelegate() {
@Override
public JDBCException convert(SQLException sqlException, String message, String sql) {
final int errorCode = JdbcExceptionHelper.extractErrorCode( sqlException );
if (errorCode == SQLITE_TOOBIG || errorCode == SQLITE_MISMATCH) {
return new DataException( message, sqlException, sql );
}
else if (errorCode == SQLITE_BUSY || errorCode == SQLITE_LOCKED) {
return new LockAcquisitionException( message, sqlException, sql );
}
else if ((errorCode >= SQLITE_IOERR && errorCode <= SQLITE_PROTOCOL) || errorCode == SQLITE_NOTADB) {
return new JDBCConnectionException( message, sqlException, sql );
}
// returning null allows other delegates to operate
return null;
}
};
}
public ViolatedConstraintNameExtracter getViolatedConstraintNameExtracter() {
return EXTRACTER;
}
private static final ViolatedConstraintNameExtracter EXTRACTER = new TemplatedViolatedConstraintNameExtracter() {
@Override
protected String doExtractConstraintName(SQLException sqle) throws NumberFormatException {
final int errorCode = JdbcExceptionHelper.extractErrorCode( sqle );
if (errorCode == SQLITE_CONSTRAINT) {
return extractUsingTemplate( "constraint ", " failed", sqle.getMessage() );
}
return null;
}
};
// union subclass support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@Override
public boolean supportsUnionAll() {
return true;
}
// DDL support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@Override
public boolean canCreateSchema() {
return false;
}
@Override
public boolean hasAlterTable() {
// As specified in NHibernate dialect
return false;
}
@Override
public boolean dropConstraints() {
return false;
}
@Override
public boolean qualifyIndexName() {
return false;
}
@Override
public String getAddColumnString() {
return "add column";
}
@Override
public String getDropForeignKeyString() {
throw new UnsupportedOperationException( "No drop foreign key syntax supported by SQLiteDialect" );
}
@Override
public String getAddForeignKeyConstraintString(String constraintName,
String[] foreignKey, String referencedTable, String[] primaryKey,
boolean referencesPrimaryKey) {
throw new UnsupportedOperationException( "No add foreign key syntax supported by SQLiteDialect" );
}
@Override
public String getAddPrimaryKeyConstraintString(String constraintName) {
throw new UnsupportedOperationException( "No add primary key syntax supported by SQLiteDialect" );
}
@Override
public boolean supportsCommentOn() {
return true;
}
@Override
public boolean supportsIfExistsBeforeTableName() {
return true;
}
/* not case insensitive for unicode characters by default (ICU extension needed)
public boolean supportsCaseInsensitiveLike() {
return true;
}
*/
@Override
public boolean doesReadCommittedCauseWritersToBlockReaders() {
// TODO Validate (WAL mode...)
return true;
}
public boolean doesRepeatableReadCauseReadersToBlockWriters() {
return true;
}
@Override
public boolean supportsTupleDistinctCounts() {
return false;
}
public int getInExpressionCountLimit() {
// Compile/runtime time option: http://sqlite.org/limits.html#max_variable_number
return 1000;
}
@Override
public UniqueDelegate getUniqueDelegate() {
return uniqueDelegate;
}
private static class SQLiteUniqueDelegate extends DefaultUniqueDelegate {
public SQLiteUniqueDelegate(Dialect dialect) {
super( dialect );
}
@Override
public String getColumnDefinitionUniquenessFragment(Column column) {
return " unique";
}
}
@Override
public String getSelectGUIDString() {
return "select hex(randomblob(16))";
}
@Override
public ScrollMode defaultScrollMode() {
return ScrollMode.FORWARD_ONLY;
}
}
SQLiteDialectIdentityColumnSupport.java ：
package org.hibernate.dialect.identity;
public class SQLiteDialectIdentityColumnSupport extends IdentityColumnSupportImpl {
@Override
public boolean supportsIdentityColumns() {
return true;
}
/*
public boolean supportsInsertSelectIdentity() {
return true; // As specified in NHibernate dialect
}
*/
@Override
public boolean hasDataTypeInIdentityColumn() {
// As specified in NHibernate dialect
// FIXME true
return false;
}
/*
public String appendIdentitySelectToInsert(String insertString) {
return new StringBuffer(insertString.length()+30). // As specified in NHibernate dialect
append(insertString).
append("; ").append(getIdentitySelectString()).
toString();
}
*/
@Override
public String getIdentitySelectString(String table, String column, int type) {
return "select last_insert_rowid()";
}
@Override
public String getIdentityColumnString(int type) {
// return "integer primary key autoincrement";
// FIXME "autoincrement"
return "integer";
}
}
我的语言表格结构：
CREATE TABLE "languages"(
language_id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
language_name VARCHAR(50) NOT NULL,
language_code VARCHAR(3) NOT NULL)
通过使用try catch块，我设法得到了这一行：
Session opened!
org.hibernate.HibernateException: The internal connection pool has reached its maximum size and no connection is currently available!
Jun 30, 2017 4:55:50 PM org.hibernate.engine.internal.StatisticalLoggingSessionEventListener end
INFO: Session Metrics {
72982 nanoseconds spent acquiring 2 JDBC connections;
0 nanoseconds spent releasing 0 JDBC connections;
0 nanoseconds spent preparing 0 JDBC statements;
0 nanoseconds spent executing 0 JDBC statements;
0 nanoseconds spent executing 0 JDBC batches;
0 nanoseconds spent performing 0 L2C puts;
0 nanoseconds spent performing 0 L2C hits;
0 nanoseconds spent performing 0 L2C misses;
0 nanoseconds spent executing 0 flushes (flushing a total of 0 entities and 0 collections);
0 nanoseconds spent executing 0 partial-flushes (flushing a total of 0 entities and 0 collections)
}
使用的库：sqlite-jdbc-3.16.1.jar和hibernate 5.2.10
答案 0 :(得分：1)
我最终通过将@GeneratedValue(strategy = GenerationType.AUTO)替换为@GeneratedValue(strategy = GenerationType.IDENTITY)来解决了这个问题。