jdbc之MetaData_获取数据库信息

最新推荐文章于 2024-07-19 20:18:03 发布

原创最新推荐文章于 2024-07-19 20:18:03 发布 · 909 阅读

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#jdbc #metadata #数据库信息

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本文详细介绍了如何通过Java操作数据库获取元数据，并解析数据库中所有表及其表信息，包括表名、列名和列类型等关键数据。通过示例代码展示了如何连接数据库、获取表信息、遍历表字段并打印相关信息。

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package jdbc;

import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;

public class MetaData {

	/**
	 * @Title: main
	 * @Description:
	 * @param：
	 * @return void 
	 * @user： wangzg
	 * @Date：2014-6-27
	 * @throws
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub

		Connection conn = null;
		Statement st = null;
		ResultSet rs = null;
		ResultSet rsTwo = null;
		
		try {
			conn = getConnection();
			System.out.println("++++++++++++++++++++++++++++++++++++++");
			//数据库源数据
			DatabaseMetaData dbmd = conn.getMetaData();
			System.out.println("URL:"+dbmd.getURL());
			System.out.println("UserName:"+dbmd.getUserName());
			
		    rs = dbmd.getTables(conn.getCatalog(), dbmd.getUserName(), null,new String[]{"TABLE"});
		    //ResultSet源数据
		    ResultSetMetaData rsmd=rs.getMetaData();
			System.out.println("该数据库中所有表及其表信息："+"共："+rsmd.getColumnCount()+"列：");
			
			while(rs.next()){
				System.out.println("++++++++++++++++++++++++++++++++++++++");
				for(int i = 1 ; i<= rsmd.getColumnCount(); i++){
					if("VARCHAR2".equals(rsmd.getColumnTypeName(i))){
						System.out.print(rsmd.getColumnName(i)+":"+rs.getString(rsmd.getColumnName(i))+",");
					}
				}
				System.out.println();
				System.out.println("++++++++++++++++++++++++++++++++++++++");
			    st = conn.createStatement();
				String sql = "select * from "+rs.getString("TABLE_NAME");
//				boolean flg = st.execute(sql);
//				if(flg){
//					rsTwo = st.getResultSet();
//				}else{
//					int count = st.getUpdateCount();
//				}
//				
			    rsTwo = st.executeQuery(sql);
				while(rsTwo.next()){
					//ResultSet源数据
					ResultSetMetaData rsmdTwo=rsTwo.getMetaData();
					System.out.println("表"+rs.getString("TABLE_NAME")+"共："+rsmdTwo.getColumnCount()+"列：");
					for(int j = 1 ; j<= rsmdTwo.getColumnCount(); j++){
						
						if("VARCHAR2".equals(rsmdTwo.getColumnTypeName(j))){
							System.out.print(rsmdTwo.getColumnName(j)+":"+rsmdTwo.getCatalogName(j)+":"+rsTwo.getString(rsmdTwo.getColumnName(j))+",");
						}else if("DATE".equals(rsmdTwo.getColumnTypeName(j))){
							System.out.print(rsmdTwo.getColumnName(j)+":"+rsTwo.getDate(rsmdTwo.getColumnName(j))+",");
						}
					}
					System.out.println();
				}
				System.out.println("++++++++++++++++++++++++++++++++++++++");
			}
			
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally{
			try {
				if(rs != null){
					rs.close();
				}
				if(rsTwo != null){
					rsTwo.close();
				}
				if(st != null){
					st.close();
				}
				if(conn != null && !conn.isClosed()){
					conn.close();
				}
				System.out.println(" Connection is closed ?"+conn.isClosed());
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		
	}
	/**
	 * 获得数据库连接
	 * @Title: getConnection
	 * @Description: 获得数据库连接
	 * @param：
	 * @return Connection 
	 * @user： wangzg
	 * @Date：2014-6-27
	 * @throws ClassNotFoundException, SQLException
	 */
	public static Connection getConnection() throws ClassNotFoundException, SQLException{
		Connection conn = null;
		
		//加载oracle驱动
		Class.forName("oracle.jdbc.driver.OracleDriver");
		
		//连接数据库
		String url = "jdbc:oracle:thin:@127.0.0.1:1521:ORCL";
		String user ="wzg";
		String password = "wzg";
		conn = DriverManager.getConnection(url, user, password);
		
//		url = "jdbc:oracle:thin:@127.0.0.1:1521:ORCL?user=wzg&password=wzg";
//		conn = DriverManager.getConnection(url);
//		
//		Properties info = new Properties();
//		info.setProperty("user", "wzg");
//		info.setProperty("password", "wzg");
//		conn = DriverManager.getConnection(url, info);
		
		return conn;
		
	}
	/**
	 * 
	 * @Title: getConnection2
	 * @Description:
	 * @param：
	 * @return Connection 
	 * @user： wangzg
	 * @Date：2014-6-27
	 * @throws
	 */
	public static Connection getConnection2() throws ClassNotFoundException, SQLException{
		Connection conn = null;
		
		//加载oracle驱动
		DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver());
		//连接数据库
		String url = "jdbc:oracle:thin:@127.0.0.1:1521:ORCL";
		String user ="wzg";
		String password = "wzg";
		conn = DriverManager.getConnection(url, user, password);
		
		return conn;
		
	}
	
	public static Connection getConnection3() throws SQLException{
		Connection conn = null;
		
		//加载oracle驱动
		System.setProperty("jdbc.drivers","oracle.jdbc.driver.OracleDriver");
		//连接数据库
		String url = "jdbc:oracle:thin:@127.0.0.1:1521:ORCL";
		String user ="wzg";
		String password = "wzg";
		conn = DriverManager.getConnection(url, user, password);
		
		return conn;
	}

}