原因：java.sql.SQLException：不支持的字符编码'utf8mb4'

Question

我正在编写一个将大量使用utf-8编码的应用程序。 对于服务器我使用的是Java servlet，而对于UI，我使用的是带有jsp和javascript的Java Servlet。
因此，在忽略了一段时间的乱码后，我决定解决utf-8编码问题。 在寻找一个解决方案，我做了一个过滤器类
我跟着@ cosoant的答案在这里：https://stackoverflow.com/questions/138948/how-to-get-utf-8-working-in-java-webapps，直到“MySQL数据库和表”（不含），因为我仍然<property name="hibernate.hbm2ddl.auto" value="create" />我persistence.xml发展。
这才明白MySQL的UTF-8是不完全的世界UTF-8的休息，所以我改变的characterEncoding persistence.xml中来：<property name="hibernate.connection.characterEncoding" value="utf8mb4" /> 此外，以下这一点：https://mathiasbynens.be/notes/mysql-utf8mb4链接我升级MySqlServer，并补充说：

[客户] 默认字符集= utf8mb4

[MySQL的]默认字符集= utf8mb4

的[mysqld]字符集的客户端握手= FALSE字符集服务器= utf8mb4 C ollat​​ion-server = utf8mb4_unicode_ci

to mysql.cnf。 我通过键入终端sudo service mysql restart重新启动mysql和确信，当我进入mysql命令行界面，然后键入：SHOW VARIABLES WHERE Variable_name LIKE 'character\_set\_%' OR Variable_name LIKE 'collation%';这样的：

+--------------------------+--------------------+ 
| Variable_name   | Value    | 
+--------------------------+--------------------+ 
| character_set_client  | utf8mb4   | 
| character_set_connection | utf8mb4   | 
| character_set_database | utf8mb4   | 
| character_set_filesystem | binary    | 
| character_set_results | utf8mb4   | 
| character_set_server  | utf8mb4   | 
| character_set_system  | utf8    | 
| collation_connection  | utf8mb4_unicode_ci | 
| collation_database  | utf8mb4_unicode_ci | 
| collation_server   | utf8mb4_unicode_ci | 
+--------------------------+--------------------+ 

是我所得到的。
我也转换com.mysql.jdbc_5.1.5.jar与mysql-connector-java-5.1.44-bin.jar。

而且，我每次尝试访问数据库时都会出现上述错误。
这是我的堆栈跟踪：

Exception in thread "main" java.lang.ExceptionInInitializerError 
    at tests.Test.main(Test.java:38) 
Caused by: org.hibernate.service.spi.ServiceException: Unable to create requested service [org.hibernate.engine.jdbc.env.spi.JdbcEnvironment] 
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:271) 
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:233) 
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:210) 
    at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:51) 
    at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:94) 
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:242) 
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:210) 
    at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.handleTypes(MetadataBuildingProcess.java:352) 
    at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:111) 
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:858) 
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:885) 
    at org.hibernate.jpa.HibernatePersistenceProvider.createEntityManagerFactory(HibernatePersistenceProvider.java:58) 
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:55) 
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:39) 
    at utils.HibernateUtil.<clinit>(HibernateUtil.java:9) 
    ... 1 more 
Caused by: org.hibernate.exception.JDBCConnectionException: Error calling Driver#connect 
    at org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator$1$1.convert(BasicConnectionCreator.java:105) 
    at org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator.convertSqlException(BasicConnectionCreator.java:123) 
    at org.hibernate.engine.jdbc.connections.internal.DriverConnectionCreator.makeConnection(DriverConnectionCreator.java:41) 
    at org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator.createConnection(BasicConnectionCreator.java:58) 
    at org.hibernate.engine.jdbc.connections.internal.PooledConnections.addConnections(PooledConnections.java:123) 
    at org.hibernate.engine.jdbc.connections.internal.PooledConnections.<init>(PooledConnections.java:42) 
    at org.hibernate.engine.jdbc.connections.internal.PooledConnections.<init>(PooledConnections.java:20) 
    at org.hibernate.engine.jdbc.connections.internal.PooledConnections$Builder.build(PooledConnections.java:161) 
    at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.buildPool(DriverManagerConnectionProviderImpl.java:109) 
    at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure(DriverManagerConnectionProviderImpl.java:72) 
    at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:94) 
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:242) 
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:210) 
    at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.buildJdbcConnectionAccess(JdbcEnvironmentInitiator.java:145) 
    at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:66) 
    at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:35) 
    at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.initiateService(StandardServiceRegistryImpl.java:88) 
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:259) 
    ... 15 more 
Caused by: java.sql.SQLException: Unsupported character encoding 'utf8mb4'. 
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:964) 
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:897) 
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:886) 
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:860) 
    at com.mysql.jdbc.ConnectionPropertiesImpl.postInitialization(ConnectionPropertiesImpl.java:2549) 
    at com.mysql.jdbc.ConnectionPropertiesImpl.initializeProperties(ConnectionPropertiesImpl.java:2519) 
    at com.mysql.jdbc.ConnectionImpl.initializeDriverProperties(ConnectionImpl.java:3140) 
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:763) 
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47) 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) 
    at sun.reflect.D Exception in thread "main" java.lang.ExceptionInInitializerError 
    at tests.Test.main(Test.java:38) 
Caused by: org.hibernate.service.spi.ServiceException: Unable to create requested service [org.hibernate.engine.jdbc.env.spi.JdbcEnvironment] 
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:271) 
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:233) 
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:210) 
    at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:51) 
    at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:94) 
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:242) 
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:210) 
    at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.handleTypes(MetadataBuildingProcess.java:352) 
    at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:111) 
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:858) 
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:885) 
    at org.hibernate.jpa.HibernatePersistenceProvider.createEntityManagerFactory(HibernatePersistenceProvider.java:58) 
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:55) 
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:39) 
    at utils.HibernateUtil.<clinit>(HibernateUtil.java:9) 
    ... 1 more 
Caused by: org.hibernate.exception.JDBCConnectionException: Error calling Driver#connect 
    at org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator$1$1.convert(BasicConnectionCreator.java:105) 
    at org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator.convertSqlException(BasicConnectionCreator.java:123) 
    at org.hibernate.engine.jdbc.connections.internal.DriverConnectionCreator.makeConnection(DriverConnectionCreator.java:41) 
    at org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator.createConnection(BasicConnectionCreator.java:58) 
    at org.hibernate.engine.jdbc.connections.internal.PooledConnections.addConnections(PooledConnections.java:123) 
    at org.hibernate.engine.jdbc.connections.internal.PooledConnections.<init>(PooledConnections.java:42) 
    at org.hibernate.engine.jdbc.connections.internal.PooledConnections.<init>(PooledConnections.java:20) 
    at org.hibernate.engine.jdbc.connections.internal.PooledConnections$Builder.build(PooledConnections.java:161) 
    at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.buildPool(DriverManagerConnectionProviderImpl.java:109) 
    at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure(DriverManagerConnectionProviderImpl.java:72) 
    at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:94) 
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:242) 
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:210) 
    at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.buildJdbcConnectionAccess(JdbcEnvironmentInitiator.java:145) 
    at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:66) 
    at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:35) 
    at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.initiateService(StandardServiceRegistryImpl.java:88) 
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:259) 
    ... 15 more 
Caused by: java.sql.SQLException: Unsupported character encoding 'utf8mb4'. 
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:964) 
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:897) 
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:886) 
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:860) 
    at com.mysql.jdbc.ConnectionPropertiesImpl.postInitialization(ConnectionPropertiesImpl.java:2549) 
    at com.mysql.jdbc.ConnectionPropertiesImpl.initializeProperties(ConnectionPropertiesImpl.java:2519) 
    at com.mysql.jdbc.ConnectionImpl.initializeDriverProperties(ConnectionImpl.java:3140) 
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:763) 
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47) 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) 
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) 
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423) 
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:425) 
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:389) 
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:330) 
    at org.hibernate.engine.jdbc.connections.internal.DriverConnectionCreator.makeConnection(DriverConnectionCreator.java:38) 
    ... 30 moreelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) 
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423) 
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:425) 
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:389) 
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:330) 
    at org.hibernate.engine.jdbc.connections.internal.DriverConnectionCreator.makeConnection(DriverConnectionCreator.java:38) 
    ... 30 more 

我想我的地方我坚持这一点。
我很感激任何帮助。 谢谢！

Answer 1

的Hibernate XML配置文件中试试这个：

<property name="hibernate.connection.CharSet">utf8mb4</property> 
<property name="hibernate.connection.characterEncoding">utf8</property‌​> 
<property name="hibernate.connection.useUnicode">true</property> 

另外，还要更改连接网址如下：

db.url=jdbc:mysql://localhost:3306/db_name?useUnicode=true&character_set_server=utf8mb4 

上述改变足以让我从UTF8到utf8mb4升级charset方案。

作为一个附注，我想澄清一点，UTF8是字符编码，而UTF8MB4是MySQL支持的字符集。 UTF8MB4是UTF8的超集。请参阅此链接了解更多信息：https://dev.mysql.com/doc/refman/5.5/en/charset-unicode-utf8mb4.html