Question

使用jdbc连接mysql为什么报错？

Answer 1

当我用JDBC连接MySql数据库时，编译报了如下错误：
错误1：
Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.
这要求我们注册驱动时，把Class.forName("com.mysql.jdbc.Driver");改成 Class.forName("com.mysql.cj.jdbc.Driver");

当我信息满满的修改之后重新编译时，再次出现了错误：
错误2：
Fri Feb 22 08:55:38 CST 2019 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.
这要求我们在设置url参数时，将useSSL=false，修改后 jdbc:mysql://localhost:3306/ds3?useSSL=false

当我修改后，本以为这下应该没问题了，没想到，再一次出现了问题
错误3：
Exception in thread "main" java.sql.SQLException: The server time zone value 'Öйú±ê׼ʱ¼ä' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc time zone value if you want to utilize time zone support.
这要求我们修改时区，修改成jdbc:mysql://localhost:3306/ds3?useSSL=false&serverTimezone=UTC

终于，不在报错误了。
错误4：当我们配置xml文件时，要把&转为其本身的转义字符
配置properties文件的urlurl=jdbc:mysql:///ds3?useSSL=false&serverTimezone=UTC配置xml文件的url<property name="url">jdbc:mysql://localhost:3306/ds3?useSSL=false&serverTimezone=UTC</property>

Answer 2

你为什么不指定连接的数据库地址和端口，这样怎么连