1.读取数据正常，插入中文乱码查看链接处制定的字符集，这里使用utf-8
String url = "jdbc:mysql://127.0.0.1:3306/website?useUnicode=true&characterEncoding=utf-8 ";
完整代码如下：
public mysqlConnect() {
String driver = "com.mysql.jdbc.Driver";
// URL指向要访问的数据库名website
String url = "jdbc:mysql://127.0.0.1:3306/website?useUnicode=true&characterEncoding=utf-8 ";
// MySQL配置时的用户名
String user = "root";
// Java连接MySQL配置时的密码
String password = "sanyue";
try {
// 加载驱动程序
Class.forName(driver);
conn = (Connection) DriverManager.getConnection(url,user, password);
if (!conn.isClosed())
System.out.println("Succeeded connecting to the Database!");
// statement用来执行SQL语句
statement = (Statement) conn.createStatement();
} catch (Exception e) {
e.printStackTrace();
statement = null;
}
}
2.查看mysql和数据库本身默认是否采用的utf8编码
此处使用 set character_set_database="utf8";
修改后在重启mysql后会不起作用，所以请找到您的 mysql的配置文件 my.ini或my.cnf 在[mysqld]的中添加character_set_server=utf8，注意有些是default-character-set=utf8
，重新启动服务器时如果出错可以查看错误日志，最后会给出我在配置的过程中遇到的几个错误
mysql> show variables like "character%"; +--------------------------+----------------------------+ | Variable_name | Value | +--------------------------+----------------------------+ | character_set_client | utf8 | | character_set_connection | utf8 | | character_set_database | utf8 | | character_set_filesystem | binary | | character_set_results | utf8 | | character_set_server | utf8 | | character_set_system | utf8 | | character_sets_dir | /usr/share/mysql/charsets/ | +--------------------------+----------------------------+ 8 rows in set (0.00 sec)
3.看页面本身是否是utf8编码。
4.看页面使用的编码是否是utf8编码
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
基本上这几个步骤如果都正常就不会出错，但是存在一些情况。
例如，本次配置时我是利用的set character_set_database="utf8";在数据库中直接修改的字符编码，但是一直没有发现重启之后或者退出再次链接之后会回复为原来的latin1，所以一直以为数据库 本身编码没有问题。
另外，java 链接数据库的链接
String url = "jdbc:mysql://127.0.0.1:3306/website?useUnicode=true&characterEncoding=utf-8 ";
不要写错，中间的&实际为 & 注意（此处由于编译器变为了&）
String url = "jdbc:mysql://127.0.0.1:3306/website?useUnicode=true&characterEncoding=utf-8 ";
以下是遇到的一些错误：
mysql 错误日志
InnoDB: Unable to lock ./ibdata1, error: 11
InnoDB: Check that you do not already have another mysqld process
InnoDB: using the same InnoDB data or log files.
InnoDB: Unable to lock ./ibdata1, error: 11
InnoDB: Check that you do not already have another mysqld process
InnoDB: using the same InnoDB data or log files.
InnoDB: Unable to lock ./ibdata1, error: 11
InnoDB: Check that you do not already have another mysqld process
InnoDB: using the same InnoDB data or log files.
解决办法：
[email protected]:/var/lib/mysql# ps -ef | grep mysql
mysql 24477 1 0 16:35 ? 00:00:00 /usr/sbin/mysqld
root 24533 1908 0 16:35 pts/0 00:00:00 /bin/sh /usr/bin/mysqld_safe
mysql 25382 24533 0 16:37 pts/0 00:00:00 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib/mysql/plugin --user=mysql --log-error=/var/log/mysql/error.log --pid-file=/var/run/mysqld/mysqld.pid --socket=/var/run/mysqld/mysqld.sock
--port=3306
root 25476 1908 0 16:37 pts/0 00:00:00 /bin/sh /usr/bin/mysqld_safe
mysql 25839 25476 0 16:37 pts/0 00:00:00 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib/mysql/plugin --user=mysql --log-error=/var/log/mysql/error.log --pid-file=/var/run/mysqld/mysqld.pid --socket=/var/run/mysqld/mysqld.sock
--port=3306
root 26204 21859 0 16:38 pts/16 00:00:00 grep --color=auto mysql
[email protected]:/var/lib/mysql# kill -9 24477
[email protected]:/var/lib/mysql# kill -9 24533
....
错误日志
[email protected]:/var/lib/mysql# tail ../../log/mysql/error.log
150616 16:40:19 InnoDB: Using Linux native AIO
150616 16:40:19 InnoDB: Initializing buffer pool, size = 128.0M
150616 16:40:19 InnoDB: Completed initialization of buffer pool
150616 16:40:19 InnoDB: highest supported file format is Barracuda.
150616 16:40:20 InnoDB: Waiting for the background threads to start
150616 16:40:21 InnoDB: 5.5.43 started; log sequence number 6583039
150616 16:40:21 [ERROR] /usr/sbin/mysqld: unknown variable ‘default-character-set=utf8‘
150616 16:40:21 [ERROR] Aborting
解决方案：
打开mysql配置文件（这里在 /etc/mysql/my.cnf）
找到 [mysqld]中
用character_set_server=utf8来取代
default-character-set=utf8