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mysql 连不上java
发表在Java图书答疑
2020-05-23 
悬赏：5 学分
《Java从入门到精通（第4版）》第20章 数据库操作
悬赏：5 学分
《Java从入门到精通（第4版）》第20章 数据库操作
是否精华
是
否
版块置顶:
是
否
老师：
我用的是mysql8.0版，java 总是连不上
出现这个
sql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server.
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:400)
at com.mysql.jdbc.Util.getInstance(Util.java:383)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:958)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:937)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:926)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:872)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2326)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2079)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:794)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:44)
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:400)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:399)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:325)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at Conn.getConnection(Conn.java:12)
at Conn.main(Conn.java:22)
Caused by: java.lang.NullPointerException
at com.mysql.jdbc.ConnectionImpl.getServerCharset(ConnectionImpl.java:2999)
at com.mysql.jdbc.MysqlIO.sendConnectionAttributes(MysqlIO.java:1885)
at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1814)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1207)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2249)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2280)
... 14 more
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