Connection con ;
con = DriverManager.getConnection(url,userName,password);
DatabaseMetaData dbmd = con.getMetaData();

ResultSet DatabaseMetaData.getTables(String catalog,String schema,String tableName,String []type)

ResultSet DatabaseMetaData getColumns(String catalog,String schema,String tableName,String columnName)

ResultSet DatabaseMetaData getPrimaryKeys(String catalog,String schema,String tableName)

import java.sql.Connection;

import java.sql.DatabaseMetaData;

import java.sql.DriverManager;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

import java.util.ArrayList;

import java.util.List;

public class dababase {

private String url="jdbc:oracle:thin:@localhost:1521:zhyl";

//服务器地址：，端口号：1521，数据库实例名字：zhyl。

private String username="andatabase";

private String pw="oracl";

private Connection conn=null;

//用户名字和密码是自己建立的。

public Connection OpenConn(){

try {

Class.forName("oracle.jdbc.driver.OracleDriver");

try {

conn=DriverManager.getConnection(url,username,pw);

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

} catch (ClassNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return conn;

}

public ResultSet executeQuery(String sql){

dababase db = new dababase();

ResultSet rs = null;

Connection con =db.OpenConn();

  try {

    Statement sm = con.createStatement();

  　　rs = sm.executeQuery(sql);

  } catch (SQLException e) {

   // TODO Auto-generated catch block

   e.printStackTrace();

  }
  return rs;

}

public void close(){

  try {

   conn.close();

  } catch (SQLException e) {

   // TODO Auto-generated catch block

   e.printStackTrace();

  }
}

// 获取数据库中所有表的表名，并添加到列表结构中。

public List getTableNameList(Connection conn) throws SQLException {

DatabaseMetaData dbmd = conn.getMetaData();

//访问当前用户ANDATABASE下的所有表

ResultSet rs = dbmd.getTables("null", "ANDATABASE", "%", new String[] { "TABLE" });

//System.out.println("kkkkkk"+dbmd.getTables("null", "%", "%", new String[] { "TABLE" }));

List tableNameList = new ArrayList();

while (rs.next()) {

tableNameList.add(rs.getString("TABLE_NAME"));

}

return tableNameList;

}

// 获取数据表中所有列的列名，并添加到列表结构中。

public List getColumnNameList(Connection conn, String tableName)

throws SQLException {

DatabaseMetaData dbmd = conn.getMetaData();

ResultSet rs = dbmd.getColumns(null, "%", tableName, "%");

List columnNameList = new ArrayList();

while (rs.next()) {

columnNameList.add(rs.getString("COLUMN_NAME"));

}

return columnNameList;

}

public static void main(String s[]) throws SQLException

{

dababase dbConn = new dababase();

Connection conn = dbConn.OpenConn();

if(conn==null)

System.out.println("连接失败");

else

System.out.println("连接成功");

try {

List tableList = dbConn.getTableNameList(conn);//取出当前用户的所有表

//List tableList = dbConn.getColumnNameList(conn, "LOGIN");//表名称必须是大写的，取出当前表的所有列

System.out.println(tableList.size());

for (Object object : tableList) {

String ss=(String)object;

System.out.println(ss);
}
} catch (SQLException e) {

e.printStackTrace();

} finally {

if (conn != null) {

try {

conn.close();

} catch (SQLException e) {

e.printStackTrace();

}
}
}
}
}