Java连接MySQL数据库，并进行增删改查

1、具体的代码实现

import java.sql.*;

public class DatabaseService  {

	/**
	 * Create Connection
	 *
	 * @param dbtype
	 * @param username
	 * @param password
	 * @param url
	 * @return
	 * @throws Exception
	 */
	public static Connection connectDBDriver(String dbtype, String username,
			String password, String url) throws Exception {
		Connection conn = null;
		try {
			if (dbtype.equals("mysql")) {
				Class.forName("com.mysql.jdbc.Driver").newInstance();
			} else if (dbtype.equals("oracle")) {
				Class.forName("oracle.jdbc.driver.OracleDriver").newInstance();
			} else {

			}
			conn = DriverManager.getConnection(url, username, password);

		} catch (Exception e) {
			e.printStackTrace();

		}
		return conn;
	}

	/**
	 * close DB
	 *
	 * @param conn
	 * @throws Exception
	 */
	public void closeDBDriver(Connection conn) throws Exception {
		try {
			conn.close();

		} catch (Exception e) { /* ignore close errors */
			e.printStackTrace();

		}
	}

	/**
	 * get ResultSet
	 *
	 * @param conn
	 * @param sql
	 * @return
	 * @throws Exception
	 */
	private static ResultSet getResultSet(Connection conn, String sql)
			throws Exception {
		ResultSet resultSet = null;
		try {
			// PreparedStatement pstmt;
			// ResultSet rset;
			//任意的前后滚动;设置为只读类型的参数
			Statement statement = conn.createStatement(
					ResultSet.TYPE_SCROLL_INSENSITIVE,
					ResultSet.CONCUR_READ_ONLY);
			// pstmt = conn.prepareStatement(sql);
			resultSet = statement.executeQuery(sql);
		} catch (Exception e) {
			e.printStackTrace();

		}
		return resultSet;
	}

	/**
	 * get ColumnCount
	 *
	 * @param resultSet
	 * @return
	 * @throws Exception
	 */
	private static int getColumnCount(ResultSet resultSet) throws Exception {
		int columnCount = 0;
		try {
			// ResultSet resultSet = this.getResultSet(conn, sql);
			//getMetaData()  获取此 ResultSet 对象的列的编号、类型和属性
			//getColumnCount()  返回此 ResultSet 对象中的列数。
			columnCount = resultSet.getMetaData().getColumnCount();
			if (columnCount == 0) {

			}
		} catch (Exception e) {
			e.printStackTrace();

		}
		return columnCount;
	}

	/**
	 * get ColumnCount
	 *
	 * @param conn
	 * @param sql
	 * @return
	 * @throws Exception
	 */
	public static int getColumnCount(Connection conn, String sql) throws Exception {
		int columnCount = 0;
		try {
			// ResultSet resultSet = this.getResultSet(conn, sql);
			columnCount = getResultSet(conn, sql).getMetaData()
					.getColumnCount();
			if (columnCount == 0) {

			}
		} catch (Exception e) {
			e.printStackTrace();

		}
		return columnCount;
	}

	/**
	 * get RowCount
	 *
	 * @param conn
	 * @param sql
	 * @return
	 * @throws Exception
	 */
	public int getRowCount(Connection conn, String sql) throws Exception {
		int rowCount = 0;
		try {
			ResultSet resultSet = getResultSet(conn, sql);
			// boolean	last()  将光标移动到此 ResultSet 对象的最后一行。
			resultSet.last();
			// boolean	last()  将光标移动到此 ResultSet 对象的最后一行。
			rowCount = resultSet.getRow();
			if (rowCount == 0) {

			}
		} catch (Exception e) {
			e.printStackTrace();

		}
		return rowCount;
	}

	/**
	 * get RowCount
	 *
	 * @param resultSet
	 * @return
	 * @throws Exception
	 */
	private static int getRowCount(ResultSet resultSet) throws Exception {
		int rowCount = 0;
		try {
			resultSet.last();
			rowCount = resultSet.getRow();
			if (rowCount == 0) {

			}
		} catch (Exception e) {
			e.printStackTrace();

		}
		return rowCount;
	}

	/**
	 * get data by row index and col index
	 *
	 * @param conn
	 * @param sql
	 * @param row
	 * @param col
	 * @return
	 * @throws Exception
	 */
	public static String getData(Connection conn, String sql, int row, int col)
			throws Exception {
		String data = null;
		int rownum = 0;
		int rowcount = 0;
		int colcount = 0;
		try {
			ResultSet resultSet = getResultSet(conn, sql);
			colcount = getColumnCount(resultSet);
			rowcount = getRowCount(resultSet);
			//beforeFirst() 将光标移动到此 ResultSet 对象的开头，正好位于第一行之前。
			resultSet.beforeFirst();
			if (rowcount > 0) {
				if (row <= 0 || row > rowcount) {

				} else {
					if (col <= 0 || col > colcount) {

					} else {
						while (resultSet.next()) {
							rownum++;
							if (rownum == row) {
								data = resultSet.getString(col);
								break;
							}
						}
					}
				}
			} else {

			}
		} catch (Exception e) {
			e.printStackTrace();

		}
		return data;
	}

	/**
	 * get data by row index and col index
	 *
	 * @param conn
	 * @param sql
	 * @param row
	 * @param field
	 * @return
	 * @throws Exception
	 */
	public static String getData(Connection conn, String sql, int row, String field)
			throws Exception {
		String data = null;
		int rownum = 0;
		int rowcount = 0;
		// int colcount = 0;
		try {
			ResultSet resultSet = getResultSet(conn, sql);
			// colcount = getColumnCount(resultSet);
			rowcount = getRowCount(resultSet);
			resultSet.beforeFirst();
			if (rowcount > 0) {
				if (row <= 0 || row > rowcount) {

				} else {
					while (resultSet.next()) {
						rownum++;
						if (rownum == row) {
							data = resultSet.getString(field);
							break;
						}
					}
				}
			} else {

			}
		} catch (Exception e) {
			e.printStackTrace();

		}
		return data;
	}

	// executeUpdate方法可以执行新增、更新、删除三种sql语句
	public static int executeUpdate(Connection conn, String sql) {
		Statement stmt = null;
		try {
			stmt = conn.createStatement();
			stmt.executeUpdate(sql);
			int updateCount = stmt.getUpdateCount();
			return updateCount;
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (stmt != null) {
				try {
					stmt.close();
				} catch (SQLException e) {
					e.printStackTrace();
				}
			}
		}
		return 0;
	}

}

　　2、调用函数实现增删改查

public class JdbcData {
     public static void main(String[] args) {
        Connection connection = databaseService.connectDBDriver("mysql","username","password","URL");
        String sql = "XXXX'";
        //查询数据，获取到数据
        String data = DatabaseService.getData(connection, sql,1,1);
        String sqlstatus = "XXXX";
        //update数据
        DatabaseService.executeUpdate(connection,sqlstatus);
     }
}