bbs_article_tree.java

总结用JDBC连接mysql数据库的程序样例

package com.JDBC;

import java.sql.*; 

public class bbs_Article_Tree {

	
	public static void main(String[] args) {
		new bbs_Article_Tree().show() ;
	}
	
	public void show()
	{
		Connection conn = null ;
		Statement  stmt = null ;
		ResultSet  rs = null ;
		try {
			Class.forName("com.mysql.jdbc.Driver") ;
			String url = "jdbc:mysql://localhost/bbs?user=root&password=dinglinbin" ;
			conn = DriverManager
			.getConnection(url) ;
			stmt = conn.createStatement() ;
			rs = stmt.executeQuery("select * from article where pid = 0") ;
			
			while(rs.next()){
				System.out.println(rs.getString("cont")) ;
				tree(conn,rs.getInt("id") , 1) ;
			}
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch(SQLException e){
			e.printStackTrace() ;
		}finally {
			try {
				if(rs != null) {
					rs.close();
					rs = null;
				}
				if(stmt != null) {
					stmt.close();
					stmt = null;
				}
				if(conn != null) {
					conn.close();
					conn = null;
				}
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}		
	}
	private void tree(Connection conn , int id , int layer )
	{
		Statement stmt = null ;
		ResultSet rs = null ;
		String sql = "select * from article where pid = " + id ;
		StringBuffer strPre = new StringBuffer("") ;
		for(int i = 0 ;i < layer ; i ++)
		{
			strPre.append("   ") ;
		}
		try {
			stmt = conn.createStatement() ;
			rs = stmt.executeQuery(sql) ;
			while(rs.next())
			{
				System.out.println(strPre + rs.getString("cont")) ;
				if(rs.getInt("isleaf") != 0 )
					tree(conn,rs.getInt("id") , layer + 1 ) ;
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
			try{
				if(rs != null){
					rs.close() ;
					rs = null ;
				}
				if(stmt != null ){
					stmt.close() ;
					stmt = null ;
				}
			} catch(SQLException e){
				e.printStackTrace() ;
			}
		}

		
	}

}