运行javaweb项目之后,就出现这个问题,mysql使用的是mysql8最新刚从官网下的,驱动也是最新的,然后数据库使用utf-8编码,但是运行了就出现Unknown character set index for field '255' received from server.问题,网上百度各种改编码都不行,求助啊求助啊。
在捣腾免费数据库时,使用的一个数据库提供商的服务器使用utf8mb4编码,而我的jar包还是八百年前的。然后。。。然后就报错了。。。
(1) MYSQL 5.5 之前, UTF8 编码只支持1-3个字节;从MYSQL5.5开始,可支持4个字节UTF编码utf8mb4;如emoji表情需要使用utf8mb4
(2) 如果服务器级使用的编码是utf8mb4(在客户端链接后使用sql语句show v
今天有同学在搭建主从环境的时候发现一个问题,简单说明一下。感谢 @年代80s.
现象:
从库上Slave_IO_Running停止,Last_Error显示如下:
bin/mysqlbinlog: Character <em>set</em> ‘#45′ is not a compiled <em>character</em> <em>set</em> and is not specified in the ‘...
应用遇到异常报警:
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet successfully <em>received</em> <em>from</em> the server was 23,579 milliseconds ago. The la
OGG迁移,目标端已经升级为12C,所以用的12版本的OGG,参数还是用的以前11g的,但是启动应用进程的时候提示OGG-03510错误,如下:
The source database <em>character</em> <em>set</em> is <em>unknown</em>, and the SOURCECHARSET parameter is not specified.
源端是sqlserver环境,之前源端是oracle环
安装完hive时,运行没问题,后来再次开启时出现如下问题:
hive> show databases;
FAILED: Error in metadata: javax.jdo.JDOFatalDataStoreException: Communications link failure
The last packet sent successfully to the server
I’ve noticed that occasionally a data node will be reported in the namenode web ui as “dead” for a minute or two and then move back to live. This morning I found this in the data node log
2011-08-
OGG同步字符集从US7ASCII to ZHS16GBK故障解决
系统环境
源端:
aix 5.3
oracle 9.2.0.7 for rac
IP 192.168.124.1
ogg 11.1.1.1.2
字符集 US7ASCII
目标端:
Red hat 6.5
oracle 11.2.0.4
utf8mb4和utf8的区别如下:
utf8一个字符最多3字节,而utf8mb4则扩展到一个字符最多能有4字节,所以能支持更多的字符集。
MySQL 需要支持 emoji 表情符号版本需要大于5.5.3,且字符集需要设置为utf8mb4 字符集。
1、设置数据表结构字符集
ALTER TABLE p_wechat_user CONVERT TO CHARACT
环境:阿里云 centos 6.5 mysql 5.6 python
问题:通过uri里面设置 char<em>set</em>=utf8mb4 连接数据库时,发生问题
Character <em>set</em> ‘utf8mb4’ is not a compiled <em>character</em> <em>set</em> and is not specified in the ‘/path/mysql/char<em>set</em>s/Index.xml’ fi
将《精通Hibernate》书中光盘源码在Eclipse3.1中调了大半天,还找了几个同事,都没有解决这个问题,请大家帮忙看看,异常信息如下:rnrn10:19:43,463 INFO Environment:483 - Hibernate 2.1.8rn10:19:43,479 INFO Environment:517 - loaded properties <em>from</em> resource hibernate.properties: hibernate.connection.username=root, hibernate.connection.password=ideal, hibernate.cglib.use_reflection_optimizer=true, hibernate.dialect=net.sf.hibernate.dialect.MySQLDialect, hibernate.show_sql=true, hibernate.connection.url=jdbc:mysql://localhost:3306/SAMPLEDB, hibernate.connection.driver_class=com.mysql.jdbc.Driverrn10:19:43,479 INFO Environment:543 - using CGLIB reflection optimizerrn10:19:43,479 INFO Environment:572 - using JDK 1.4 java.sql.Timestamp handlingrn10:19:43,494 INFO Configuration:909 - configuring <em>from</em> resource: /hibernate.cfg.xmlrn10:19:43,494 INFO Configuration:881 - Configuration resource: /hibernate.cfg.xmlrn10:19:43,978 INFO Configuration:332 - Mapping resource: mypack/Customer.hbm.xmlrn10:19:44,119 INFO Binder:229 - Mapping class: mypack.Customer -> CUSTOMERSrn10:19:44,197 INFO Configuration:1067 - Configured SessionFactory: nullrn10:19:44,197 INFO Configuration:641 - processing one-to-many association mappingsrn10:19:44,197 INFO Configuration:650 - processing one-to-one association property referencesrn10:19:44,197 INFO Configuration:675 - processing foreign key constraintsrn10:19:44,228 INFO Dialect:86 - Using dialect: net.sf.hibernate.dialect.MySQLDialectrn10:19:44,244 INFO SettingsFactory:70 - Maximim outer join fetch depth: 2rn10:19:44,244 INFO SettingsFactory:74 - Use outer join fetching: truern10:19:44,259 INFO DriverManagerConnectionProvider:42 - Using Hibernate built-in connection pool (not for production use!)rn10:19:44,259 INFO DriverManagerConnectionProvider:43 - Hibernate connection pool size: 20rn10:19:44,259 INFO DriverManagerConnectionProvider:77 - using driver: org.gjt.mm.mysql.Driver at URL: jdbc:mysql://localhost:3306/SAMPLEDBrn10:19:44,259 INFO DriverManagerConnectionProvider:78 - connection properties: user=root, password=idealrn10:19:44,275 INFO TransactionManagerLookupFactory:33 - No TransactionManagerLookup configured (in JTA environment, use of process level read-write cache is not recommended)rn10:19:44,556 WARN SettingsFactory:107 - Could not obtain connection metadatarnjava.sql.SQLException: Unknown <em>character</em> <em>set</em>: 'dos'rn at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2847)rn at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1531)rn at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1622)rn at com.mysql.jdbc.Connection.execSQL(Connection.java:2370)rn at com.mysql.jdbc.Connection.configureClientCharacterSet(Connection.java:3033)rn at com.mysql.jdbc.Connection.initializePropsFromServer(Connection.java:3215)rn at com.mysql.jdbc.Connection.createNewIO(Connection.java:1780)rn at com.mysql.jdbc.Connection.(Connection.java:430)rn at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:268)rn at java.sql.DriverManager.getConnection(DriverManager.java:512)rn at java.sql.DriverManager.getConnection(DriverManager.java:140)rn at net.sf.hibernate.connection.DriverManagerConnectionProvider.getConnection(DriverManagerConnectionProvider.java:101)rn at net.sf.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:84)rn at net.sf.hibernate.cfg.Configuration.buildSettings(Configuration.java:1172)rn at net.sf.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:803)rn at mypack.BusinessService.(BusinessService.java:20)rn10:19:44,556 INFO SettingsFactory:114 - Use scrollable result <em>set</em>s: falsern10:19:44,556 INFO SettingsFactory:117 - Use JDBC3 getGeneratedKeys(): falsern10:19:44,556 INFO SettingsFactory:120 - Optimize cache for minimal puts: falsern10:19:44,556 INFO SettingsFactory:126 - echoing all SQL to stdoutrn10:19:44,556 INFO SettingsFactory:129 - Query language substitutions: rn10:19:44,556 INFO SettingsFactory:140 - cache provider: net.sf.hibernate.cache.EhCacheProviderrn10:19:44,571 INFO Configuration:1130 - instantiating and configuring cachesrn10:19:44,587 WARN Configurator:125 - No configuration found. Configuring ehcache <em>from</em> ehcache-failsafe.xml found in the classpath: jar:file:/E:/Projects/Test/WebRoot/WEB-INF/lib/ehcache-0.9.jar!/ehcache-failsafe.xmlrn10:19:44,743 INFO SessionFactoryImpl:119 - building session factoryrn10:19:45,102 INFO SessionFactoryObjectFactory:82 - Not binding factory to JNDI, no JNDI name configuredrn10:19:45,180 WARN JDBCExceptionReporter:57 - SQL Error: 1115, SQLState: 42000rn10:19:45,180 ERROR JDBCExceptionReporter:58 - Unknown <em>character</em> <em>set</em>: 'dos'rnnet.sf.hibernate.exception.GenericJDBCException: Cannot open connectionrn at net.sf.hibernate.exception.ErrorCodeConverter.handledNonSpecificException(ErrorCodeConverter.java:90)rn at net.sf.hibernate.exception.ErrorCodeConverter.convert(ErrorCodeConverter.java:79)rn at net.sf.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:29)rn at net.sf.hibernate.impl.BatcherImpl.convert(BatcherImpl.java:328)rn at net.sf.hibernate.impl.BatcherImpl.openConnection(BatcherImpl.java:295)rn at net.sf.hibernate.impl.SessionImpl.connect(SessionImpl.java:3373)rn at net.sf.hibernate.impl.SessionImpl.connection(SessionImpl.java:3333)rn at net.sf.hibernate.transaction.JDBCTransaction.begin(JDBCTransaction.java:40)rn at net.sf.hibernate.transaction.JDBCTransactionFactory.beginTransaction(JDBCTransactionFactory.java:19)rn at net.sf.hibernate.impl.SessionImpl.beginTransaction(SessionImpl.java:2252)rn at mypack.BusinessService.saveCustomer(BusinessService.java:54)rn at mypack.BusinessService.test(BusinessService.java:184)rn at mypack.BusinessService.main(BusinessService.java:194)rnCaused by: java.sql.SQLException: Unknown <em>character</em> <em>set</em>: 'dos'rn at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2847)rn at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1531)rn at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1622)rn at com.mysql.jdbc.Connection.execSQL(Connection.java:2370)rn at com.mysql.jdbc.Connection.configureClientCharacterSet(Connection.java:3033)rn at com.mysql.jdbc.Connection.initializePropsFromServer(Connection.java:3215)rn at com.mysql.jdbc.Connection.createNewIO(Connection.java:1780)rn at com.mysql.jdbc.Connection.(Connection.java:430)rn at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:268)rn at java.sql.DriverManager.getConnection(DriverManager.java:512)rn at java.sql.DriverManager.getConnection(DriverManager.java:140)rn at net.sf.hibernate.connection.DriverManagerConnectionProvider.getConnection(DriverManagerConnectionProvider.java:101)rn at net.sf.hibernate.impl.BatcherImpl.openConnection(BatcherImpl.java:292)rn ... 8 morernException in thread "main"
以下是转帖,翻译了Rockford Lhotka在04年写的一片文章: 众所周知的,一个典型的应用程序有界面层、业务层和数据层。在我的大部分作品中,我使用的是4层模型:界面、业务、数据访问、数据存储层(UI, business, data access and data storage).在这个案例中,数据存储层确实与传统3层结构中的相同。 原著: http://www.thes
异常一:Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered
via the SPI and manual loading of the driver