relationcom.java

一个信息发布系统 基于jsp+servlet+tomcat 用户分管理员跟普通用户 普通用户有发布信息 查询信息 修改信息 回复信息 管理员拥有普通用户的功能 此外还具有删除信息 管理信息的回复的功能

package control;
import model.*;
import java.util.Vector;
import java.sql.*;
public class RelationCom 
{
    //private String Parent = "";
    //private String[] Chilrren = null;
    //private int ID = 0;
	private Connection con; 
    
	public RelationCom(String url,String database,String pasw)
    {
    	con = new GetConnection(url,database,pasw).getConnection();
    }
	
	public  void addRelation(String parent,String child,String CPath)
	{
		PreparedStatement pre,pre2;
		String sql = "insert into relation(PCName,CCName,CPath) values(?,?,?)";
		String sql2 = "update relation set HasChild = true where CCName=?";
		try
		{
			pre = con.prepareStatement(sql);
            pre.setString(1, parent);
            pre.setString(2, child);
            pre.setString(3, CPath);
            pre.execute();
            pre2 = con.prepareStatement(sql2);
            pre2.setString(1, parent);
            pre2.execute();
		}
		catch(SQLException e){}	
	}
	
	public void delRelation(String Name)
	{
		Vector children = getChildren(Name);
		if(children!=null)
		{
			for(int i = 0;i<children.size();++i)
			{
				delRelation((String)children.get(i));
			}
		}
		PreparedStatement pre,pre2;
		String sql = "delete from relation where CCName = ?";
		String parent = getParent(Name);
		String sql2 = "select * from relation where PCName = ?";
		try
		{
			pre = con.prepareStatement(sql);
            pre.setString(1, Name);
            pre.execute();
            pre2 = con.prepareStatement(sql2);
            pre2.setString(1, parent);
            ResultSet rs = pre2.executeQuery();
            if(!rs.next())
            {
            	String sql3 = "update relation set HasChild = false where CCName=?";
            	PreparedStatement pre3;
            	pre3 = con.prepareStatement(sql3);
            	pre3.setString(1, parent);
            	pre3.execute();
            }
            /*pre = con.prepareStatement(sql);
            pre.setString(1, Name);
            pre.execute();*/
		}
		catch(SQLException e){}	
	}
	
	public String getParent(String childname)
	{
		PreparedStatement pre;
		String parent = null;
		String sql = "select PCName from relation where CCName = ?";
		try
		{
				pre = con.prepareStatement(sql);
				pre.setString(1, childname);
				ResultSet rs = pre.executeQuery();
				while(rs.next())
				{
					parent = rs.getString("PCName");
				}
		}
		catch(SQLException e){return null;}
		return parent;
	}
	
	public Vector getChildren(String parentname)
	{
		PreparedStatement pre;
		Vector children = new Vector();
		String sql = "select CCName from relation where PCName = ?";
		try
		{
				pre = con.prepareStatement(sql);
				pre.setString(1, parentname);
				ResultSet rs = pre.executeQuery();
				while(rs.next())
				{
					children.add(rs.getString("CCName"));
				}
		}
		catch(SQLException e){return null;}
		return children;
	}
}