Hibernate - 沒有為jdbc找到合適的驅動程序：mysql // *

Question

我試圖在Web項目引用的Java項目中運行hibernate。 很簡單，除了我不能讓hibernate連接到我的數據庫。 我有很多人描述這個問題並得到大量答案，但似乎沒有人對我有用。

這就是我的hibernate.cfg.xml的樣子：

<?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>
    <!-- Database connection settings -->
     <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
     <property name="hibernate.connection.url">jdbc:mysql//localhost:3306/dbname</property>
     <property name="hibernate.connection.username">root</property>
     <property name="hibernate.connection.password">commander</property>

     <!-- JDBC connection pool (use the built-in) -->
    <property name="connection.pool_size">50</property>

    <!-- SQL dialect -->
    <property name="dialect">org.hibernate.dialect.MySQLDialect</property>

    <!-- Enable Hibernate's automatic session context management -->
    <property name="current_session_context_class">thread</property>

    <!-- Enable the second-level cache  -->
    <property name="cache.provider_class">org.hibernate.cache.EhCacheProvider</property>

    <!-- Echo all executed SQL to stdout -->
    <property name="show_sql">true</property>

    <!-- Drop and re-create the database schema on startup -->
    <property name="hbm2ddl.auto">update</property>

    <mapping resource="com/amakena/profile/mapping/Credentials.hbm.xml"/>
    <mapping resource="com/amakena/profile/mapping/Profile.hbm.xml"/>
    <mapping resource="com/amakena/profile/mapping/City.hbm.xml"/>
    <mapping resource="com/amakena/profile/mapping/Country.hbm.xml"/>
    <mapping resource="com/amakena/profile/mapping/Gender.hbm.xml"/>
</session-factory>
</hibernate-configuration>

我將代碼調試到DriverManagerConnectionProvider類，嘗試getConnection（）方法拋出異常

Connection conn = DriverManager.getConnection(url, connectionProps);

我檢查了url和connectionProps，它們是hibernate.cfg.xml中的那些

in my tomcat \\lib folder and I can see it in eclipse under Libraries>Apache Tomcat v6.0>. 我在我的tomcat \\ lib文件夾中添加了 ，我可以在eclipse下的Libraries> Apache Tomcat v6.0>中看到它。 我還將它添加到我的％Javahome％\\ lib \\ ext和我的CLASSPATH變量（我知道這是無用的，因為我很絕望）。

我確保通過在session.beginTransaction（）之前運行以下代碼來正確安裝我的驅動程序，這反過來導致DriverManagerConnectionProvider.getConnection（）

Class.forName("com.mysql.jdbc.Driver");
Properties connectionProperties = new Properties();
connectionProperties.put("user", "root");
connectionProperties.put("password", "root");
DriverManager.getConnection("jdbc:mysql://localhost:3306/dbname", connectionProperties); 

我注意到發出第一行會導致相同的異常。

拋出異常

WARNING: Method execution failed: 
org.hibernate.exception.JDBCConnectionException: Cannot open connection
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:99)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:52)
at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:449)
at org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:167)
at org.hibernate.jdbc.JDBCContext.connection(JDBCContext.java:160)
at org.hibernate.transaction.JDBCTransaction.begin(JDBCTransaction.java:81)
at org.hibernate.impl.SessionImpl.beginTransaction(SessionImpl.java:1473)
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.context.ThreadLocalSessionContext$TransactionProtectionWrapper.invoke(ThreadLocalSessionContext.java:345)
at $Proxy0.beginTransaction(Unknown Source)
at com.amakena.profile.dao.CredentialsDao.hydrate(CredentialsDao.java:45)
at com.amakena.profile.ProfileManager.login(ProfileManager.java:19)
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.directwebremoting.impl.ExecuteAjaxFilter.doFilter(ExecuteAjaxFilter.java:34)
at org.directwebremoting.impl.DefaultRemoter$1.doFilter(DefaultRemoter.java:428)
at org.directwebremoting.impl.DefaultRemoter.execute(DefaultRemoter.java:431)
at org.directwebremoting.impl.DefaultRemoter.execute(DefaultRemoter.java:283)
at org.directwebremoting.servlet.PlainCallHandler.handle(PlainCallHandler.java:52)
at org.directwebremoting.servlet.UrlProcessor.handle(UrlProcessor.java:101)
at org.directwebremoting.servlet.DwrServlet.doPost(DwrServlet.java:146)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Unknown Source)

Caused by: java.sql.SQLException: No suitable driver found for jdbc:mysql//localhost:3306/dbname
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at org.hibernate.connection.DriverManagerConnectionProvider.getConnection(DriverManagerConnectionProvider.java:133)
at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:446)
... 37 more
WARNING: --Erroring: batchId[24] message[org.hibernate.exception.JDBCConnectionException: Cannot open connection]

我很感激能得到的所有幫助。 提前致謝。

使用的版本：Tomcat v6.0 - Hibernate 3.6.6 - Java 6 - Eclipse 3.5.2 R35x

Answer 1

你在“mysql”之后忘記了冒號：

 <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/dbname</property>

這是URL格式的文檔 ：

jdbc:mysql://[host][,failoverhost...][:port]/[database]

沒有合適的驅動程序總是意味着驅動程序JAR已加載，但您的URL語法不正確。

Answer 2

jdbc:mysql://localhost:3306/dbname

你錯過了：在mysql之后

Answer 3

另一個原因是找不到驅動程序類，請確保您的驅動程序類已成功加載。