日志中存在以下错误。当字符串 \xF0\x9F\x98\x94 作为参数传递时，会发生此错误。此值无法保存到表中，因此会引发不正确的字符串值错误。我想知道传递这种价值的原因是什么。这是黑客攻击吗？我不知道 \xF0\x9F\x98\x94 作为后表单参数传递时是什么意思。我感谢任何帮助！谢谢！
ERROR 2018-08-19 16:14:40,369 [ajp-bio-8109-exec-2808] util.JDBCExceptionReporter: Incorrect string value: 'xF0x9Fx98x94 B...' for column 'body' at row 1
ERROR 2018-08-19 16:14:40,372 [ajp-bio-8109-exec-2808] events.PatchedDefaultFlushEventListener: Could not synchronize database state with session
org.hibernate.exception.GenericJDBCException: could not update: [EventEmailDraft#42]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.sql.SQLException: Incorrect string value: 'xF0x9Fx98x94 B...' for column 'body' at row 1
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1073)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4098)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4030)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2490)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2651)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2677)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2134)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2434)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2352)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2337)
at org.apache.commons.dbcp.DelegatingPreparedStatement.executeUpdate(DelegatingPreparedStatement.java:105)
at org.apache.commons.dbcp.DelegatingPreparedStatement.executeUpdate(DelegatingPreparedStatement.java:105)
... 3 more
ERROR 2018-08-19 16:14:40,377 [ajp-bio-8109-exec-2808] errors.GrailsExceptionResolver: SQLException occurred when processing request: [POST] /roadrace/message/saveDraft
Incorrect string value: 'xF0x9Fx98x94 B...' for column 'body' at row 1. Stacktrace follows:
org.springframework.jdbc.UncategorizedSQLException: Hibernate operation: could not update: [EventEmailDraft#42]; uncategorized SQLException for SQL [update event_email_draft set version=?, body=?, emails=?, event_id=?, subject=? where id=? and version=?]; SQL state [HY000]; error code [1366]; Incorrect string value: 'xF0x9Fx98x94 B...' for column 'body' at row 1; nested exception is java.sql.SQLException: Incorrect string value: 'xF0x9Fx98x94 B...' for column 'body' at row 1
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.sql.SQLException: Incorrect string value: 'xF0x9Fx98x94 B...' for column 'body' at row 1
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1073)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4098)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4030)
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:2677)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2134)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2434)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2352)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2337)
at org.apache.commons.dbcp.DelegatingPreparedStatement.executeUpdate(DelegatingPreparedStatement.java:105)
at org.apache.commons.dbcp.DelegatingPreparedStatement.executeUpdate(DelegatingPreparedStatement.java:105)
... 3 more
这是由超过 3 个字节组成的 Unicode 序列
groovy:000> new String([0xF0, 0x9F, 0x98, 0x94] as byte[], 'UTF-8')
===> 😔
MySQL 中 UTF-8 的默认值是仅保存 3 个字节。
一个适当的解释可以在这里找到 mysql 中的 utf8mb4 和 utf8 字符集有什么区别？ 后续问题，如"我如何改变它"也在这里得到解答。