mysql資料庫字符集

問題：最近在做專案時，打算在本地搭建專案執行的全部環境，當環境搭建好之後，在進行測試時，突然發現程式向資料庫插入資料時發生了亂碼。

最先想到的解決方案：

• 檢查eclipse的字符集（頁面字符集、code字符集等）
• 檢查tomcat的URIEncoding
• 檢查資料來源連線的字符集
• 檢查資料庫服務的字符集

經過層層檢查，最終鎖定到資料庫服務的字符集是非utf8的；

解決方案：

1. 檢視mysql字符集

    show variables like '%character%'
   

2. 修改mysql的my.ini檔案

    檔案位置：一般位於：
    			1、C:\ProgramData\MySQL\MySQL Server 5.7。
    		  	2、%MYSQL_HOME% 下。
   

my.ini檔案內容：注意其中[client]、 [mysql] 、 [mysqld]的字符集配置形式（解決亂碼問題的關鍵）

	# Other default tuning values
	# MySQL Server Instance Configuration File
	# ----------------------------------------------------------------------
	# Generated by the MySQL Server Instance Configuration Wizard
	#
	#
	# Installation Instructions
	# ----------------------------------------------------------------------
	#
	# On Linux you can copy this file to /etc/my.cnf to set global options,
	# mysql-data-dir/my.cnf to set server-specific options
	# (@
 
[email protected] for this installation) or to
	# ~/.my.cnf to set user-specific options.
	#
	# On Windows you should keep this file in the installation directory 
	# of your server (e.g. C:\Program Files\MySQL\MySQL Server X.Y). To
	# make sure the server reads the config file use the startup option 
	# "--defaults-file". 
	#
	# To run the server from the command line, execute this in a 
	# command line shell, e.g.
	# mysqld --defaults-file="C:\Program Files\MySQL\MySQL Server X.Y\my.ini"
	#
	# To install the server as a Windows service manually, execute this in a 
	# command line shell, e.g.
	# mysqld --install MySQLXY --defaults-file="C:\Program Files\MySQL\MySQL Server X.Y\my.ini"
	#
	# And then execute this in a command line shell to start the server, e.g.
	# net start MySQLXY
	#
	#
	# Guidelines for editing this file
	# ----------------------------------------------------------------------
	#
	# In this file, you can use all long options that the program supports.
	# If you want to know the options a program supports, start the program
	# with the "--help" option.
	#
	# More detailed information about the individual options can also be
	# found in the manual.
	#
	# For advice on how to change settings please see
	# http://dev.mysql.com/doc/refman/5.7/en/server-configuration-defaults.html
	#
	#
	# CLIENT SECTION
	# ----------------------------------------------------------------------
	#
	# The following options will be read by MySQL client applications.
	# Note that only client applications shipped by MySQL are guaranteed
	# to read this section. If you want your own MySQL client program to
	# honor these values, you need to specify it as an option during the
	# MySQL client library initialization.
	#
	[client]
	
	# pipe=
	
	# socket=MYSQL
	
	port=3306
	
	[mysql]
	no-beep
	
	# default-character-set=
	
	# SERVER SECTION
	# ----------------------------------------------------------------------
	#
	# The following options will be read by the MySQL Server. Make sure that
	# you have installed the server correctly (see above) so it reads this 
	# file.
	#
	# server_type=3
	[mysqld]
	
	# The next three options are mutually exclusive to SERVER_PORT below.
	# skip-networking
	# enable-named-pipe
	# shared-memory
	
	# shared-memory-base-name=MYSQL
	
	# The Pipe the MySQL Server will use
	# socket=MYSQL
	
	# The TCP/IP Port the MySQL Server will listen on
	port=3306
	
	# Path to installation directory. All paths are usually resolved relative to this.
	# basedir="C:/Program Files/MySQL/MySQL Server 5.7/"
	
	# Path to the database root
	datadir=C:/ProgramData/MySQL/MySQL Server 5.7/Data
	
	# The default character set that will be used when a new schema or table is
	# created and no character set is defined
	character-set-server=utf8
	
	# The default storage engine that will be used when create new tables when
	default-storage-engine=INNODB
	
	# Set the SQL mode to strict
	sql-mode="STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"
	
	# General and Slow logging.
	log-output=FILE
	
	general-log=0
	
	general_log_file="JATHAMS.log"
	
	slow-query-log=1
	
	slow_query_log_file="JATHAMS-slow.log"
	
	long_query_time=10
	
	# Binary Logging.
	# log-bin
	
	# Error Logging.
	log-error="JATHAMS.err"
	
	# Server Id.
	server-id=1
	
	# Specifies the on how table names are stored in the metadata.
	# If set to 0, will throw an error on case-insensitive operative systems
	# If set to 1, table names are stored in lowercase on disk and comparisons are not case sensitive.
	# If set to 2, table names are stored as given but compared in lowercase.
	# This option also applies to database names and table aliases.
	lower_case_table_names=1
	
	# Secure File Priv.
	secure-file-priv="C:/ProgramData/MySQL/MySQL Server 5.7/Uploads"
	
	# The maximum amount of concurrent sessions the MySQL server will
	# allow. One of these connections will be reserved for a user with
	# SUPER privileges to allow the administrator to login even if the
	# connection limit has been reached.
	max_connections=151
	
	# The number of open tables for all threads. Increasing this value
	# increases the number of file descriptors that mysqld requires.
	# Therefore you have to make sure to set the amount of open files
	# allowed to at least 4096 in the variable "open-files-limit" in
	# section [mysqld_safe]
	table_open_cache=2000
	
	# Maximum size for internal (in-memory) temporary tables. If a table
	# grows larger than this value, it is automatically converted to disk
	# based table This limitation is for a single table. There can be many
	# of them.
	tmp_table_size=37M
	
	# How many threads we should keep in a cache for reuse. When a client
	# disconnects, the client's threads are put in the cache if there aren't
	# more than thread_cache_size threads from before.  This greatly reduces
	# the amount of thread creations needed if you have a lot of new
	# connections. (Normally this doesn't give a notable performance
	# improvement if you have a good thread implementation.)
	thread_cache_size=10
	
	#*** MyISAM Specific options
	# The maximum size of the temporary file MySQL is allowed to use while
	# recreating the index (during REPAIR, ALTER TABLE or LOAD DATA INFILE.
	# If the file-size would be bigger than this, the index will be created
	# through the key cache (which is slower).
	myisam_max_sort_file_size=100G
	
	# If the temporary file used for fast index creation would be bigger
	# than using the key cache by the amount specified here, then prefer the
	# key cache method.  This is mainly used to force long character keys in
	# large tables to use the slower key cache method to create the index.
	myisam_sort_buffer_size=64M
	
	# Size of the Key Buffer, used to cache index blocks for MyISAM tables.
	# Do not set it larger than 30% of your available memory, as some memory
	# is also required by the OS to cache rows. Even if you're not using
	# MyISAM tables, you should still set it to 8-64M as it will also be
	# used for internal temporary disk tables.
	key_buffer_size=8M
	
	# Size of the buffer used for doing full table scans of MyISAM tables.
	# Allocated per thread, if a full scan is needed.
	read_buffer_size=64K
	
	read_rnd_buffer_size=256K
	
	#*** INNODB Specific options ***
	# innodb_data_home_dir=
	
	# Use this option if you have a MySQL server with InnoDB support enabled
	# but you do not plan to use it. This will save memory and disk space
	# and speed up some things.
	# skip-innodb
	
	# If set to 1, InnoDB will flush (fsync) the transaction logs to the
	# disk at each commit, which offers full ACID behavior. If you are
	# willing to compromise this safety, and you are running small
	# transactions, you may set this to 0 or 2 to reduce disk I/O to the
	# logs. Value 0 means that the log is only written to the log file and
	# the log file flushed to disk approximately once per second. Value 2
	# means the log is written to the log file at each commit, but the log
	# file is only flushed to disk approximately once per second.
	innodb_flush_log_at_trx_commit=1
	
	# The size of the buffer InnoDB uses for buffering log data. As soon as
	# it is full, InnoDB will have to flush it to disk. As it is flushed
	# once per second anyway, it does not make sense to have it very large
	# (even with long transactions).
	innodb_log_buffer_size=1M
	
	# InnoDB, unlike MyISAM, uses a buffer pool to cache both indexes and
	# row data. The bigger you set this the less disk I/O is needed to
	# access data in tables. On a dedicated database server you may set this
	# parameter up to 80% of the machine physical memory size. Do not set it
	# too large, though, because competition of the physical memory may
	# cause paging in the operating system.  Note that on 32bit systems you
	# might be limited to 2-3.5G of user level memory per process, so do not
	# set it too high.
	innodb_buffer_pool_size=8M
	
	# Size of each log file in a log group. You should set the combined size
	# of log files to about 25%-100% of your buffer pool size to avoid
	# unneeded buffer pool flush activity on log file overwrite. However,
	# note that a larger logfile size will increase the time needed for the
	# recovery process.
	innodb_log_file_size=48M
	
	# Number of threads allowed inside the InnoDB kernel. The optimal value
	# depends highly on the application, hardware as well as the OS
	# scheduler properties. A too high value may lead to thread thrashing.
	innodb_thread_concurrency=17
	
	# The increment size (in MB) for extending the size of an auto-extend InnoDB system tablespace file when it becomes full.
	innodb_autoextend_increment=64
	
	# The number of regions that the InnoDB buffer pool is divided into.
	# For systems with buffer pools in the multi-gigabyte range, dividing the buffer pool into separate instances can improve concurrency,
	# by reducing contention as different threads read and write to cached pages.
	innodb_buffer_pool_instances=8
	
	# Determines the number of threads that can enter InnoDB concurrently.
	innodb_concurrency_tickets=5000
	
	# Specifies how long in milliseconds (ms) a block inserted into the old sublist must stay there after its first access before
	# it can be moved to the new sublist.
	innodb_old_blocks_time=1000
	
	# It specifies the maximum number of .ibd files that MySQL can keep open at one time. The minimum value is 10.
	innodb_open_files=300
	
	# When this variable is enabled, InnoDB updates statistics during metadata statements.
	innodb_stats_on_metadata=0
	
	# When innodb_file_per_table is enabled (the default in 5.6.6 and higher), InnoDB stores the data and indexes for each newly created table
	# in a separate .ibd file, rather than in the system tablespace.
	innodb_file_per_table=1
	
	# Use the following list of values: 0 for crc32, 1 for strict_crc32, 2 for innodb, 3 for strict_innodb, 4 for none, 5 for strict_none.
	innodb_checksum_algorithm=0
	
	# The number of outstanding connection requests MySQL can have.
	# This option is useful when the main MySQL thread gets many connection requests in a very short time.
	# It then takes some time (although very little) for the main thread to check the connection and start a new thread.
	# The back_log value indicates how many requests can be stacked during this short time before MySQL momentarily
	# stops answering new requests.
	# You need to increase this only if you expect a large number of connections in a short period of time.
	back_log=80
	
	# If this is set to a nonzero value, all tables are closed every flush_time seconds to free up resources and
	# synchronize unflushed data to disk.
	# This option is best used only on systems with minimal resources.
	flush_time=0
	
	# The minimum size of the buffer that is used for plain index scans, range index scans, and joins that do not use
	# indexes and thus perform full table scans.
	join_buffer_size=256K
	
	# The maximum size of one packet or any generated or intermediate string, or any parameter sent by the
	# mysql_stmt_send_long_data() C API function.
	max_allowed_packet=4M
	
	# If more than this many successive connection requests from a host are interrupted without a successful connection,
	# the server blocks that host from performing further connections.
	max_connect_errors=100
	
	# Changes the number of file descriptors available to mysqld.
	# You should try increasing the value of this option if mysqld gives you the error "Too many open files".
	open_files_limit=4161
	
	# If you see many sort_merge_passes per second in SHOW GLOBAL STATUS output, you can consider increasing the
	# sort_buffer_size value to speed up ORDER BY or GROUP BY operations that cannot be improved with query optimization
	# or improved indexing.
	sort_buffer_size=256K
	
	# The number of table definitions (from .frm files) that can be stored in the definition cache.
	# If you use a large number of tables, you can create a large table definition cache to speed up opening of tables.
	# The table definition cache takes less space and does not use file descriptors, unlike the normal table cache.
	# The minimum and default values are both 400.
	table_definition_cache=1400
	
	# Specify the maximum size of a row-based binary log event, in bytes.
	# Rows are grouped into events smaller than this size if possible. The value should be a multiple of 256.
	binlog_row_event_max_size=8K
	
	# If the value of this variable is greater than 0, a replication slave synchronizes its master.info file to disk.
	# (using fdatasync()) after every sync_master_info events.
	sync_master_info=10000
	
	# If the value of this variable is greater than 0, the MySQL server synchronizes its relay log to disk.
	# (using fdatasync()) after every sync_relay_log writes to the relay log.
	sync_relay_log=10000
	
	# If the value of this variable is greater than 0, a replication slave synchronizes its relay-log.info file to disk.
	# (using fdatasync()) after every sync_relay_log_info transactions.
	sync_relay_log_info=10000
	
	# Load mysql plugins at start."plugin_x ; plugin_y".
	# plugin_load
	
	# The TCP/IP Port the MySQL Server X Protocol will listen on.
	# loose_mysqlx_port=33060
 

配置好這個後再去檢視下MySQL的字符集；