> list = new ArrayList>();

//静态代码块，在程序编译的时候执行

static {

//创建Properties对象

Properties properties = new Properties();

//获取文件输入流

InputStream is = JDBCUtil_cj.class.getClassLoader().getResourceAsStream("jdbc.properties");

try {

//加载输入流

properties.load(is);

is.close();

//加载mysql驱动

Class.forName(properties.getProperty("driver"));

} catch (IOException e) {

e.printStackTrace();

} catch (ClassNotFoundException e) {

e.printStackTrace();

}

}

//关闭资源

public static void closeRes(Connection conn,PreparedStatement ps,ResultSet rs) {

try {

if(rs != null){

rs.close();

}

if(ps != null){

ps.close();

}

if(conn != null){

conn.close();

}

} catch (SQLException e) {

e.printStackTrace();

}

}

//获取连接

public static Connection getConnection(){

Connection conn = null;

Properties properties = new Properties();

InputStream is = JDBCUtil_cj.class.getClassLoader().getResourceAsStream("jdbc.properties");

try {

properties.load(is);

is.close();

} catch (IOException e) {

e.printStackTrace();

}

try {

conn = DriverManager.getConnection(

properties.getProperty("url"),

properties.getProperty("username"),

properties.getProperty("password"));

} catch (SQLException e) {

e.printStackTrace();

}

return conn;

}

public static void main(String[] args) {

Connection connection = getConnection();

String sql = "select * from dept where deptno = ?";

PreparedStatement preparedStatement = null;

ResultSet resultSet = null;

try {

preparedStatement = connection.prepareStatement(sql);

preparedStatement.setInt(1,10);

resultSet = preparedStatement.executeQuery();

ResultSetMetaData md = resultSet.getMetaData(); //获得结果集结构信息,元数据

int columnCount = md.getColumnCount(); //获得列数

while (resultSet.next()) {

MaprowData = new HashMap();

for (int i = 1; i <= columnCount; i++) {

rowData.put(md.getColumnName(i), resultSet.getObject(i));

}

JDBCUtil_cj cj = new JDBCUtil_cj();

cj.list.add(rowData);

for (Map.Entryentry : rowData.entrySet()) {

System.out.println(entry.getKey()+"==="+entry.getValue());

}

System.out.println(rowData);

System.out.println(cj.list);

}

} catch (SQLException e) {

e.printStackTrace();

}

JDBCUtil_cj.closeRes(connection,preparedStatement,resultSet);

}

}