我在带有MySQL 5.1数据存储区的JBoss 7服务器上运行Java Web应用程序。我使用JDBC与我的数据库进行通信。有一种特定的方法，相当于数据库查询密集型。它运行一次或两次运行正常，但运行5次后（即使它分开5次）我丢失了数据库连接，导致以下错误：
WARN [org.jboss.jca.core.connectionmanager.pool.strategy.OnePool] (http-localhost-127.0.0.1-9091-3) IJ000604: Throwable while attempting to get a new connection: null: javax.resource.ResourceException: Could not create connection
at org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory.getLocalManagedConnection(LocalManagedConnectionFactory.java:277)
at org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory.createManagedConnection(LocalManagedConnectionFactory.java:235)
at org.jboss.jca.core.connectionmanager.pool.mcp.SemaphoreArrayListManagedConnectionPool.createConnectionEventListener(SemaphoreArrayListManagedConnectionPool.java:706)
at org.jboss.jca.core.connectionmanager.pool.mcp.SemaphoreArrayListManagedConnectionPool.getConnection(SemaphoreArrayListManagedConnectionPool.java:321)
at org.jboss.jca.core.connectionmanager.pool.AbstractPool.getSimpleConnection(AbstractPool.java:392)
at org.jboss.jca.core.connectionmanager.pool.AbstractPool.getConnection(AbstractPool.java:357)
at org.jboss.jca.core.connectionmanager.AbstractConnectionManager.getManagedConnection(AbstractConnectionManager.java:351)
at org.jboss.jca.core.connectionmanager.AbstractConnectionManager.getManagedConnection(AbstractConnectionManager.java:326)
at org.jboss.jca.core.connectionmanager.AbstractConnectionManager.allocateConnection(AbstractConnectionManager.java:467)
at org.jboss.jca.adapters.jdbc.WrapperDataSource.getConnection(WrapperDataSource.java:129)
...
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Data source rejected establishment of connection, message from server: "Too many connections"
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) [:1.7.0_45]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) [:1.7.0_45]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) [:1.7.0_45]
at java.lang.reflect.Constructor.newInstance(Unknown Source) [:1.7.0_45]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.Util.getInstance(Util.java:386)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1013)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:987)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:982)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1128)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2336)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2369)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2153)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:792)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
at sun.reflect.GeneratedConstructorAccessor9.newInstance(Unknown Source) [:1.7.0_45]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) [:1.7.0_45]
at java.lang.reflect.Constructor.newInstance(Unknown Source) [:1.7.0_45]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:381)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:305)
at org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory.getLocalManagedConnection(LocalManagedConnectionFactory.java:249)
... 86 more
我做了一些关于这个问题的搜索，我怀疑我没有在某个地方正确关闭连接。我注释掉了任何进行数据库调用的方法，直到我发现了一个似乎导致问题的方法。它有几个PreparedStatements在循环中运行，但我很确定我已经在try-finally中捕获了每个调用，它关闭了所有打开的PreparedStatements和ResultSet。这是有问题的方法：
private List<SupplierDisclosureDto> getSupplierDisclosureListInClientDB(UserDto user, List<SupplierDto> coreSuppliers) throws SQLException{
List<SupplierDisclosureDto> sdList = new ArrayList<SupplierDisclosureDto>();
Connection connection = user.getConnection();
PreparedStatement psAllFragrances = null;
ResultSet rsAllFragrances = null;
PreparedStatement psFormulations = null;
ResultSet rsFormulations = null;
PreparedStatement psIfra = null;
ResultSet rsIfra = null;
PreparedStatement psDocuments = null;
ResultSet rsDocuments = null;
try{
//find all fragrances and its corresponding values
psAllFragrances = connection.prepareStatement(
"SELECT " +
"c.child_trade_name AS tradeName, c.child_supplier_name AS supplier, r.raw_material_number AS rmNo, " +
"r.id AS rid, d.id AS did, o.supplier_id AS contentRole, o.id AS oid, s.short_name AS supplierShortname " +
"FROM object o " +
"left join composition c on c.id = (SELECT cx.id FROM composition AS cx WHERE cx.child_object_id = o.id LIMIT 1) " +
"left join raw_material r on r.id = (SELECT rx.id FROM raw_material AS rx WHERE rx.object_id = o.id LIMIT 1) " +
"left join document_status d on d.id = (SELECT dx.id FROM document_status AS dx WHERE dx.raw_material_id = r.id LIMIT 1) " +
"left join supplier s on s.id = o.supplier_id " +
"WHERE o.type<>0 AND r.is_fragrance=1");
rsAllFragrances = psAllFragrances.executeQuery();
while(rsAllFragrances.next()){
SupplierDisclosureDto sd = new SupplierDisclosureDto();
sd.setContentRole(rsAllFragrances.getInt("contentRole"));
List<FormulaDto> formulas = new ArrayList<FormulaDto>();
try{
psFormulations = connection.prepareStatement(
"SELECT " +
"c.child_supplier_name AS supplier, c.child_overall_percent , ca.category , s.subcategory , p.brand , p.sub_brand , p.notebook_number , " +
"fo.status AS fStatus , f.unique_id, f.name , f.formula_number , f.version , f.date_modified_provided , f.id AS fid " +
"FROM composition c " +
"left join formula f on f.id = (SELECT fx.id FROM formula AS fx WHERE fx.object_id = c.parent_object_id LIMIT 1) " +
"left join object fo on fo.id = (SELECT fox.id FROM object AS fox WHERE fox.id = c.parent_object_id LIMIT 1) " +
"left join product p on p.id = (SELECT px.id FROM product AS px WHERE px.id = f.product_id LIMIT 1) " +
"left join subcategory s on s.id = (SELECT sx.id FROM subcategory AS sx WHERE sx.id = p.subcategory_id LIMIT 1) " +
"left join category ca on ca.id = (SELECT cax.id FROM category AS cax WHERE cax.id = s.category_id LIMIT 1) " +
"WHERE c.child_object_id=?");
psFormulations.setInt(1, sd.getParentObjectId());
rsFormulations = psFormulations.executeQuery();
while(rsFormulations.next()){
CategoryDto category = new CategoryDto();
category.setCategory(rsFormulations.getString("category"));
SubcategoryDto subcategory = new SubcategoryDto();
subcategory.setSubcategory(rsFormulations.getString("subcategory"));
subcategory.setCategory(category);
ProductDto product = new ProductDto();
product.setBrand(rsFormulations.getString("brand"));
product.setSubcategory(subcategory);
ObjectDto formulaObject = new ObjectDto();
formulaObject.setStatus(rsFormulations.getString("fStatus"));
FormulaDto formula = new FormulaDto();
formula.setFormulaNumber(rsFormulations.getString("formula_number"));
formula.setObject(formulaObject);
formula.setProduct(product);
try{
psIfra = connection.prepareStatement("SELECT i.category FROM ifra_category i WHERE i.formula_id = ?");
psIfra.setInt(1, rsFormulations.getInt("fid"));
rsIfra = psIfra.executeQuery();
List<String> ifraCategories = new ArrayList<String>();
while(rsIfra.next()){
ifraCategories.add(rsIfra.getString("category"));
}
rsIfra.close();
psIfra.close();
formula.setIfraCategories(ifraCategories.toArray(new String[ifraCategories.size()]));
}finally{
if(rsIfra!=null)
rsIfra.close();
if(psIfra!=null)
psIfra.close();
}
formulas.add(formula);
}
rsFormulations.close();
psFormulations.close();
}finally{
if(rsFormulations!=null)
rsFormulations.close();
if(psFormulations!=null)
psFormulations.close();
}
sd.setFormulas(formulas);
try{
psDocuments = connection.prepareStatement(
"SELECT " +
"d.id AS d_id, d.document_status_id, d.document_type, d.is_active AS d_is_active, d.uploaded_by, " +
"d.last_uploaded, d.previous_version_id, d.extension, d.filename, u.id AS u_id, u.user_name, u.email, u.role_id, " +
"u.content_role_id, u.client_id, u.name, u.address, u.company, u.phone_number, u.fax_number, c.short_name " +
"FROM document_status_detail d " +
"left join irw.user u on u.id = (SELECT ux.id FROM irw.user AS ux WHERE ux.id = d.uploaded_by LIMIT 1) " +
"left join irw.client c on c.id = (SELECT cx.id FROM irw.client AS cx WHERE cx.id = u.client_id LIMIT 1) " +
"WHERE d.document_status_id = ? " +
"ORDER BY document_type, last_uploaded ASC");
psDocuments.setInt(1, rsAllFragrances.getInt("did"));
rsDocuments = psDocuments.executeQuery();
SupplierDocumentDto previousDocument = null;
HashMap<String, SupplierDocumentDto> documents = new HashMap<String, SupplierDocumentDto>();
while(rsDocuments.next()){
SupplierDocumentDto currentDocument = new SupplierDocumentDto();
currentDocument.setIsActive((rsDocuments.getInt("d_is_active")==0)?false:true);
UserDto userDto = new UserDto();
userDto.setId(rsDocuments.getInt("u_id"));
currentDocument.setUploadedByUser(userDto);
if(previousDocument!=null && previousDocument.getType().equalsIgnoreCase(currentDocument.getType())){
currentDocument.setPreviousVersion(previousDocument);
}
documents.put(currentDocument.getType(), currentDocument);
previousDocument = currentDocument;
}
rsDocuments.close();
psDocuments.close();
sd.setDocuments(documents);
sdList.add(sd);
}finally{
if(rsDocuments!=null)
rsDocuments.close();
if(psDocuments!=null)
psDocuments.close();
}
}
rsAllFragrances.close();
psAllFragrances.close();
}finally{
if(rsAllFragrances!=null)
rsAllFragrances.close();
if(psAllFragrances!=null)
psAllFragrances.close();
}
return sdList;
}
当用户登录时，将初始化与数据库的连接，因为可以为不同的用户分配不同的数据库。如果有帮助，这里是我的standalone.xml中的数据存储区配置（每个数据库都是一样的）：
<datasource jndi-name="java:jboss/datasources/DATABASEDS" pool-name="DATABASEDS-Pool" enabled="true" jta="false" use-java-context="true" use-ccm="true">
<connection-url>
jdbc:mysql://localhost:3306/DATABASE?zeroDateTimeBehavior=convertToNull
</connection-url>
<driver>
mysql-connector-java-5.1.18-bin.jar
</driver>
<transaction-isolation>
TRANSACTION_READ_COMMITTED
</transaction-isolation>
<pool>
<min-pool-size>
10
</min-pool-size>
<max-pool-size>
500
</max-pool-size>
<prefill>
true
</prefill>
<use-strict-min>
false
</use-strict-min>
<flush-strategy>
FailingConnectionOnly
</flush-strategy>
</pool>
<security>
<user-name>
USERNAME
</user-name>
<password>
PASSWORD
</password>
</security>
<validation>
<check-valid-connection-sql>
SELECT 1
</check-valid-connection-sql>
<validate-on-match>
false
</validate-on-match>
<background-validation>
false
</background-validation>
<use-fast-fail>
false
</use-fast-fail>
</validation>
<timeout>
<blocking-timeout-millis>
60000
</blocking-timeout-millis>
<idle-timeout-minutes>
1
</idle-timeout-minutes>
</timeout>
<statement>
<track-statements>
TRUE
</track-statements>
<prepared-statement-cache-size>
0
</prepared-statement-cache-size>
<share-prepared-statements/>
</statement>
</datasource>
我不确定是什么导致了这个问题，我尝试了很多解决方案。任何帮助将不胜感激！
解决：
我通过一些调试发现了泄漏。事实证明，这是一种不同的方法，不断打开新的连接，但从未关闭它们。我在try-finally中包围它，确保新连接在使用完毕后立即关闭。
答案 0 :(得分：1)
尝试在应用程序启动时使用连接池或在jboss中配置它，例如：
ComboPooledDataSource connectionPoolDatasource = new ComboPooledDataSource();
connectionPoolDatasource.setDriverClass("com.mysql.jdbc.Driver");
connectionPoolDatasource.setJdbcUrl("jdbc:mysql://localhost:3306/mydatabase");
connectionPoolDatasource.setUser("root");
connectionPoolDatasource.setPassword("");
connectionPoolDatasource.setMinPoolSize(1);
connectionPoolDatasource.setAcquireIncrement(5);
connectionPoolDatasource.setMaxPoolSize(20);
Connection con = connectionPoolDatasource.getConnection();
您也可以在jboss中配置它，请参阅this链接。
答案 1 :(得分：1)
您可以尝试以下
在<cached-connection-manager debug="true"/>
<subsystem xmlns="urn:jboss:domain:jca:1.1">
JBoss将关闭泄露的连接
您需要在启用JCA日志记录后通过检查日志来查找泄漏的连接。我通过这种方式解决了连接泄漏问题。
<logger category="org.jboss.jca">
<level name="DEBUG"/>
</logger>
您将在日志中获得以下条目
DEBUG [org.jboss.jca.core.connectionmanager.pool.strategy.OnePool] (MSC service thread 1-4) {JNDI_NAME}: getConnection(null, null) [1/100] - ＆gt;这意味着从池中获取连接。
DEBUG [org.jboss.jca.core.connectionmanager.pool.strategy.OnePool] (MSC service thread 1-4) {JNDI_NAME}: returnConnection(607e334, false) [1/99] - ＆gt;这意味着返回到池的连接
您可以检查哪个查询没有返回到池的连接，并检查您的应用程序从哪个查询执行。解决它。