树形目录的递归实现数据库 jsp javabean

2008-02-23 07:54:06来源：互联网阅读 ()

树形目录的递归实现(一)数据库 jsp javabean

<%@ page contentType="text/html; charset=gb2312" language="java" import="java.sql.*" errorPage="" %>

<%!//方便起见这里就不写成javabean了
class cn {//连接数据库，这里以MS-SQL为例
String jdbcDriver="com.microsoft.jdbc.sqlserver.SQLServerDriver";//jdbc驱动
String connectionString="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=test";//数据库连接字符串
String user="sa";//数据库用户名
String pass="";//数据库密码
Connection conn=null;
ResultSet rs=null;

public cn() {
try {
Class.forName(jdbcDriver);
} catch(ClassNotFoundException e) {
System.err.println(e.toString());
}
}

public ResultSet executeQuery(String sql) {
rs=null;
try {
conn=DriverManager.getConnection(connectionString,user,pass);
Statement stmt=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
rs=stmt.executeQuery(sql);
}
catch(SQLException e) {
System.err.println(e.toString());
}
return rs;
}

public void executeUpdate(String sql) {
try {
conn=DriverManager.getConnection(connectionString,user,pass);
Statement stmt=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
stmt.executeUpdate(sql);
}
catch(SQLException e) {
System.err.println(e.toString());
}
}
}

class tree {
cn conn=new cn();
public void init(javax.servlet.jsp.JspWriter out,javax.servlet.http.HttpServletRequest request) throws Exception {
out.println("<title>用jsp种树</title>");
dowith(request);
buildTree(out,0,0);//初始调用
}

private void dowith(javax.servlet.http.HttpServletRequest request) {
if(request.getParameter("parentid")==null||request.getParameter("parentid").equals(""))return;
String action=request.getParameter("action");
if(action.equals("add"))
conn.executeUpdate("insert into tree(parentid,message) values('" request.getParameter("parentid") "','" request.getParameter("message") "')");
else if(action.equals("delete"))
conn.executeUpdate("delete from tree where id=" request.getParameter("parentid") " or parentid=" request.getParameter("parentid"));
}

public void buildTree(javax.servlet.jsp.JspWriter out,int parentid,int level) throws Exception {
level ;
ResultSet rs=conn.executeQuery("select * from tree where parentid=" parentid " order by id");
while(rs.next()) {
out.println("<div>");
for(int i=0;i<level-1;i )
out.print("<img src="white.gif"> ");
if(has_child(rs.getInt("id"))) {
out.print("<img alt="展开" style="cursor:hand;" onclick="myClick('" rs.getInt("id") "');" id="img" rs.getInt("id") "" src="plus.gif"> <img id="im" rs.getInt("id") "" src="closedfold.gif"> ");
out.print("<span onclick="myClick1('" rs.getInt("id") "');" style="cursor:default;" id="span" rs.getInt("id") "">" rs.getString("message") " id=" rs.getInt("id") "</span>");
out.println("<div style="display:none;" id="div" rs.getInt("id") "">");
buildTree(out,rs.getInt("id"),level);//递归调用
out.println("</div>");
} else
out.print("<img src="minus.gif"> <img src="openfold.gif"> <span onclick="myClick1('" rs.getInt("id") "');" style="cursor:default;" id="span" rs.getInt("id") "">" rs.getString("message") " id=" rs.getInt("id") "</span>");
out.println("</div>");
}
rs.close();
rs=null;
}

private boolean has_child(int parentid) throws Exception {
ResultSet rs=conn.executeQuery("select * from tree where parentid=" parentid " order by id");
return rs.next();
}

public String getOption() throws Exception {
String option="";
ResultSet rs=conn.executeQuery("select * from tree order by id");
while(rs.next())
option ="<option value="" rs.getInt("id") "">" rs.getInt("id") "</option> ";
return option;
}
}
%>

<script language="JavaScript">

</script>
<table>
<tr><td height="300" valign="top">
<%