IDEA 与 SQLServer 连接以及增删改查

1. 连接数据库

```java
public class DBUtil {

    public static String driverName="com.microsoft.sqlserver.jdbc.SQLServerDriver";
    public static String dbURL="jdbc:sqlserver://localhost:1433;databaseName=数据库名";
    public static String userName="用户名";
    public static String userPwd="密码";

    public static Connection getConn () {
        Connection dbConn = null;
        PreparedStatement prepareStatement = null;
        ResultSet re = null;

        try {
            Class.forName(driverName);//加载驱动
            dbConn = DriverManager.getConnection(dbURL,userName,userPwd);
            System.out.println("success");
            return dbConn;
        } catch (Exception e) {
            e.printStackTrace();
        }
        System.out.println("fail");
        return null;
    }
    /**
     * 关闭与数据库的连接
     * @param prepareStatement
     * @param dbConn
     */
    public static void close (PreparedStatement prepareStatement, Connection dbConn) {
        if (prepareStatement != null) {
            try {
                prepareStatement.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

        if (dbConn != null) {
            try {
                dbConn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    public static void close (ResultSet re, PreparedStatement prepareStatement, Connection dbConn) {
        if (re != null) {
            try {
                re.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

        if (prepareStatement != null) {
            try {
                prepareStatement.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

        if (dbConn != null) {
            try {
                dbConn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}
```

2. 对数据库进行增删改查

public boolean operation() {
		//设置sql语句

		//1.插入数据
        String sql = "insert 数据表名 values (?,?,?)";	//需要插入几个数据，就用几个问号

		//2.查询数据
		String sql = "SELECT 列名 FROM 表名 WHERE 条件";

		//3.修改数据
		String sql = "UPDATE 表名 SET 修改内容 WHERE 条件";

		//4.删除数据
		String sql = "DELETE FROM 表名 WHERE 条件";
        
        // 创建数据库链接
        Connection dbConn = DBUtil.getConn();
        PreparedStatement prepareStatement = null;
        try {
            prepareStatement = dbConn.prepareStatement(sql);
            //设置问号中具体的值
            prepareStatement.setString(1, user.getId());
            prepareStatement.setInt(2, 0);
            prepareStatement.setDate(3, null);
            prepareStatement.execute();
            System.out.println("add success");
            return true;
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            // 关闭z 连接
            DBUtil.close(prepareStatement, dbConn);
        }
        System.out.println("add fail");
        return false;
    }