import java.sql.*; //jdbc.jar

public class ArticleTree { public static void main(String[] args) { new ArticleTree().show(); }

//方法show，显示建立的树public void show() {	Connection conn = null;	Statement stmt = null;	ResultSet rs = null;	try {		Class.forName("com.mysql.jdbc.Driver");		conn = DriverManager				.getConnection("jdbc:mysql://localhost/bbs?user=root&password=root"); //建立bbs数据库的Connection conn		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) {		e.printStackTrace(); //ClassNotFoundException，无法找到指定的类异常	} 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();		}	}}//方法tree建立树,Database Connection conn已建立private void tree(Connection conn, int id, int level) {	Statement stmt = null;	//Java执行数据库操作的一个重要接口Statement，用于发送要执行的SQL语句		ResultSet rs = null;  	//database结果集的数据表ResultSet，为指针，方法next可使其移动下一行		//当对字符串进行修改的时候，需要使用 StringBuffer类	//和 String 类不同的是，StringBuffer类的对象能够被多次的修改	StringBuffer strPre = new StringBuffer("");	for(int i=0; i

}