在尝试了许多查询之后，终于成功了

ALTER TABLE
table_name
CHANGE column_name column_name 
varchar(256)
CHARACTER SET utf8mb4
COLLATE utf8mb4_unicode_ci;

如果您只想对一个字段应用更改，您可以尝试序列化该字段

class MyModel < ActiveRecord::Base
  serialize :content

  attr_accessible :content, :title
end

只做

ALTER TABLE `some_table` 
CHARACTER SET = utf8 , COLLATE = utf8_general_ci ;

ALTER TABLE `some_table` 
CHANGE COLUMN `description_with_latin_or_something` `description` TEXT CHARACTER SET 'utf8' NOT NULL ;

我的PLAY Java应用程序有这个问题。这是我对该异常的堆栈跟踪:

javax.persistence.PersistenceException: Error[Incorrect string value: '\xE0\xA6\xAC\xE0\xA6\xBE...' for column 'product_name' at row 1]
  at io.ebean.config.dbplatform.SqlCodeTranslator.translate(SqlCodeTranslator.java:52)
  at io.ebean.config.dbplatform.DatabasePlatform.translate(DatabasePlatform.java:192)
  at io.ebeaninternal.server.persist.dml.DmlBeanPersister.execute(DmlBeanPersister.java:83)
  at io.ebeaninternal.server.persist.dml.DmlBeanPersister.insert(DmlBeanPersister.java:49)
  at io.ebeaninternal.server.core.PersistRequestBean.executeInsert(PersistRequestBean.java:1136)
  at io.ebeaninternal.server.core.PersistRequestBean.executeNow(PersistRequestBean.java:723)
  at io.ebeaninternal.server.core.PersistRequestBean.executeNoBatch(PersistRequestBean.java:778)
  at io.ebeaninternal.server.core.PersistRequestBean.executeOrQueue(PersistRequestBean.java:769)
  at io.ebeaninternal.server.persist.DefaultPersister.insert(DefaultPersister.java:456)
  at io.ebeaninternal.server.persist.DefaultPersister.insert(DefaultPersister.java:406)
  at io.ebeaninternal.server.persist.DefaultPersister.save(DefaultPersister.java:393)
  at io.ebeaninternal.server.core.DefaultServer.save(DefaultServer.java:1602)
  at io.ebeaninternal.server.core.DefaultServer.save(DefaultServer.java:1594)
  at io.ebean.Model.save(Model.java:190)
  at models.Product.create(Product.java:147)
  at controllers.PushData.xlsupload(PushData.java:67)
  at router.Routes$$anonfun$routes$1.$anonfun$applyOrElse$40(Routes.scala:690)
  at play.core.routing.HandlerInvokerFactory$$anon$3.resultCall(HandlerInvoker.scala:134)
  at play.core.routing.HandlerInvokerFactory$$anon$3.resultCall(HandlerInvoker.scala:133)
  at play.core.routing.HandlerInvokerFactory$JavaActionInvokerFactory$$anon$8$$anon$2$$anon$1.invocation(HandlerInvoker.scala:108)
  at play.core.j.JavaAction$$anon$1.call(JavaAction.scala:88)
  at play.http.DefaultActionCreator$1.call(DefaultActionCreator.java:31)
  at play.core.j.JavaAction.$anonfun$apply$8(JavaAction.scala:138)
  at scala.concurrent.Future$.$anonfun$apply$1(Future.scala:655)
  at scala.util.Success.$anonfun$map$1(Try.scala:251)
  at scala.util.Success.map(Try.scala:209)
  at scala.concurrent.Future.$anonfun$map$1(Future.scala:289)
  at scala.concurrent.impl.Promise.liftedTree1$1(Promise.scala:29)
  at scala.concurrent.impl.Promise.$anonfun$transform$1(Promise.scala:29)
  at scala.concurrent.impl.CallbackRunnable.run$$$capture(Promise.scala:60)
  at scala.concurrent.impl.CallbackRunnable.run(Promise.scala)
  at play.core.j.HttpExecutionContext$$anon$2.run(HttpExecutionContext.scala:56)
  at play.api.libs.streams.Execution$trampoline$.execute(Execution.scala:70)
  at play.core.j.HttpExecutionContext.execute(HttpExecutionContext.scala:48)
  at scala.concurrent.impl.CallbackRunnable.executeWithValue(Promise.scala:68)
  at scala.concurrent.impl.Promise$KeptPromise$Kept.onComplete(Promise.scala:368)
  at scala.concurrent.impl.Promise$KeptPromise$Kept.onComplete$(Promise.scala:367)
  at scala.concurrent.impl.Promise$KeptPromise$Successful.onComplete(Promise.scala:375)
  at scala.concurrent.impl.Promise.transform(Promise.scala:29)
  at scala.concurrent.impl.Promise.transform$(Promise.scala:27)
  at scala.concurrent.impl.Promise$KeptPromise$Successful.transform(Promise.scala:375)
  at scala.concurrent.Future.map(Future.scala:289)
  at scala.concurrent.Future.map$(Future.scala:289)
  at scala.concurrent.impl.Promise$KeptPromise$Successful.map(Promise.scala:375)
  at scala.concurrent.Future$.apply(Future.scala:655)
  at play.core.j.JavaAction.apply(JavaAction.scala:138)
  at play.api.mvc.Action.$anonfun$apply$2(Action.scala:96)
  at scala.concurrent.Future.$anonfun$flatMap$1(Future.scala:304)
  at scala.concurrent.impl.Promise.$anonfun$transformWith$1(Promise.scala:37)
  at scala.concurrent.impl.CallbackRunnable.run$$$capture(Promise.scala:60)
  at scala.concurrent.impl.CallbackRunnable.run(Promise.scala)
  at akka.dispatch.BatchingExecutor$AbstractBatch.processBatch(BatchingExecutor.scala:55)
  at akka.dispatch.BatchingExecutor$BlockableBatch.$anonfun$run$1(BatchingExecutor.scala:91)
  at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:12)
  at scala.concurrent.BlockContext$.withBlockContext(BlockContext.scala:81)
  at akka.dispatch.BatchingExecutor$BlockableBatch.run(BatchingExecutor.scala:91)
  at akka.dispatch.TaskInvocation.run(AbstractDispatcher.scala:40)
  at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(ForkJoinExecutorConfigurator.scala:43)
  at akka.dispatch.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
  at akka.dispatch.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
  at akka.dispatch.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
  at akka.dispatch.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)
Caused by: java.sql.SQLException: Incorrect string value: '\xE0\xA6\xAC\xE0\xA6\xBE...' for column 'product_name' at row 1
  at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1074)
  at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4096)
  at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4028)
  at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2490)
  at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2651)
  at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2734)
  at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2155)
  at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2458)
  at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2375)
  at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2359)
  at com.zaxxer.hikari.pool.ProxyPreparedStatement.executeUpdate(ProxyPreparedStatement.java:61)
  at com.zaxxer.hikari.pool.HikariProxyPreparedStatement.executeUpdate(HikariProxyPreparedStatement.java)
  at io.ebeaninternal.server.type.DataBind.executeUpdate(DataBind.java:82)
  at io.ebeaninternal.server.persist.dml.InsertHandler.execute(InsertHandler.java:122)
  at io.ebeaninternal.server.persist.dml.DmlBeanPersister.execute(DmlBeanPersister.java:73)
  ... 59 more

我想用io.Ebean保存一条记录。我通过使用utf8mb4排序规则重新创建我的数据库来修复它，并应用play evolution重新创建所有表，以便所有表都应该使用utf-8排序规则重新创建。

CREATE DATABASE inventory CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

这主要是由一些unicode字符引起的。对我来说，它是卢比的货币符号。

为了快速修复这个问题，我必须找出导致这个错误的字符。我把整个文本复制粘贴到一个文本编辑器中，比如vi，然后用一个文本替换掉麻烦的字符。

同样的问题，要保存utf8mb4的数据，需要确保:

Character_set_client、character_set_connection、character_set_results为utf8mb4: Character_set_client和character_set_connection为客户端发送语句的字符集，character_set_results为服务器端返回查询结果给客户端的字符集。 看到charset-connection。 表和列编码为utf8mb4

对于JDBC，有两种解决方案:

解决方案一(需要重启MySQL):

修改my.cnf，重启MySQL: (mysql) default-character-set = utf8mb4 (mysqld) character-set-server = utf8mb4 collation-server = utf8mb4_unicode_ci

这可以确保数据库和character_set_client、character_set_connection、character_set_results默认为utf8mb4。

重新启动MySQL 将表和列编码更改为utf8mb4 停止在jdbc连接器中指定characterEncoding=UTF-8和characterSetResults=UTF-8，因为这将覆盖character_set_client, character_set_connection, character_set_results到utf8

解决方案二(不需要重启MySQL):

将表和列编码更改为utf8mb4 在jdbc连接器中指定characterEncoding=UTF-8，因为jdbc连接器不支持utf8mb4。 像这样写你的sql语句(需要添加allowMultiQueries=true到jdbc连接器): SET NAMES utf8mb4;INSERT INTO Mytable…

这将确保到服务器、character_set_client、character_set_connection、character_set_results的每个连接都是utf8mb4。 参见字符集连接。