项目导入mysql驱动包---简单例子

mysql驱动下载见最后

---

步骤

1. 在项目中新建libs包

2. 赋值jar包到libs中（mysql-connector-java-5.1.37-bin.jar）

3. jar包加入项目

4. 注册驱动

Class.forName("com.mysql.jdbc.Driver");

5. 获取数据库连接对象

Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/db1", "root", "root.123");

6. 定义sql语句

String sql="select * from emp";

7. 获得执行sql的对象

Statement statement = connection.createStatement();

8. 执行sql

boolean execute = statement.execute(sql);

9. 处理结果

System.out.println(execute);

10. 释放资源

statement.close();
connection.close();

遇到的问题

1. Exception in thread "main" com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server.
Caused by: java.lang.NullPointerException

解决：驱动包用错，重新下载mac版mysql驱动包

• mysql驱动下载流程：

https://dev.mysql.com/downloads/connector/j/

• 替换之前的mysql驱动

最后再重新添加新的驱动jar包

例子

    public void funTest01() {
//        Class.forName("com.mysql.jdbc.Driver");//mysql5版本之后可以删除

        Connection connection = null;
        Statement statement = null;

        try {
            connection = DriverManager.getConnection("jdbc:mysql:///student",
                    "root", "root.123");//省略localhost:3306

            String sql = "update stu set math=90 where id=2";

            statement = connection.createStatement();

            int count = statement.executeUpdate(sql);

            if(count>0){
                System.out.println("操作成功");
            }else {
                System.out.println("操作失败");
            }

        }catch (Exception e){
            e.printStackTrace();
        }finally {
            try {
                if(statement != null) {
                    statement.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
            try {
                if(connection != null) {
                    connection.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }


    }