使用jdbc连接mysql为什么报错？

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>

1、首先登陆mysql，查看mysql的数据情况，select * from test_data1 t

2、新建java类，测试jdbc功能

3、编写java的jdbc代码，

String driver = "com.mysql.cj.jdbc.Driver"

String url = "jdbc:mysql://localhost:3306/testdb?characterEncoding=utf8&useSSL=false"

String user = "root"

String pwd = "123456"

4、代码中查询mysql数据表，并执行查出表中内容；select * from test_data1

jdbc连接数据库步骤如下：

*** 作设备：戴尔笔记本电脑

*** 作系统：win10

*** 作程序：mysql jdbc

1、点击左下角的开始菜单，如下图所示：

2、输入cmd，打开命令行，如下图所示：

3、输入Net start Mysql，启动mysql服务，如下图所示：

4、先输入create database，如下图所示：

5、然后输入你想要的数据库名字，如下图所示：

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