java.lang.ClassNotFoundException: com.MySQL.jdbc.Driver
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at mypackage.DataConnection.main(DataConnection.java:19)
help我啊
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at mypackage.DataConnection.main(DataConnection.java:19)
help我啊
Class.forName("com.mysql.jdbc.Driver");注意大小写
com.MySQL.jdbc.Driver
你大小写的问题,所以没有找到
com.mysql.jdbc.Driver
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1055)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3491)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3423)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:910)
at com.mysql.jdbc.MysqlIO.secureAuth411(MysqlIO.java:3923)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1273)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2031)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:718)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:298)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:282)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at mypackage.DataConnection.main(DataConnection.java:20)
连数据库哪一项
Connection conn=DriverManager.getConnection(url,"","");
com.mysql.jdbc.exceptions.MySQLIntegrityConstraintViolationException: Duplicate entry '1' for key 1
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1011)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3491)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3423)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1936)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2060)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2542)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1734)
at com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:995)
at mypackage.DataConnection.main(DataConnection.java:28)
缺少这个类com.MySQL.jdbc.Driver,导入mysql-connector.jar试试看。java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES)
mysql服务没有启动,或者用户名和密码错误,或者root帐号不允许登录。com.mysql.jdbc.exceptions.MySQLIntegrityConstraintViolationException: Duplicate entry '1' for key 1
可能是表中主键冲突,不允许再次插入与已存在主键相同的记录。