求把下面ashx代码翻译成java代码

using System;
using System.Web;
using System.Data;

public class GetClassJsonByPid : IHttpHandler {

public void ProcessRequest (HttpContext context) {
    context.Response.ContentType = "text/plain";
    string sJsonTree = string.Empty;
    int parentId = -1;
    string pid = context.Request.QueryString["pid"];
    if (!string.IsNullOrEmpty(pid))
        Int32.TryParse(pid, out parentId);
    if (parentId>=0)
        sJsonTree = getJsonTree(parentId);
    context.Response.Write(sJsonTree);
}
public string getJsonTree(int pid)
{ 
    string resultStr = "";
    resultStr += "[";
    string sqlexe = @"select * From proclass where pid=" + pid.ToString() + " order by [Order] ASC";
    DataTable dt = mdb.db.GetDataTable(sqlexe);
    foreach (DataRow dr in dt.Rows)
    {
        string id = dr["id"].ToString();
        string state = "open";
        if (bChild(id))
            state = "closed";
        resultStr += "{";
        resultStr += string.Format("\"id\": \"{0}\", \"text\": \"{1}\", \"iconCls\": \"\", \"state\": \"" + state + "\"", dr["id"].ToString(), dr["Name"].ToString());
        resultStr += "},";
    }
    resultStr = resultStr.Substring(0, resultStr.Length - 1);                   
    resultStr += "]";
    return resultStr;
}
public Boolean bChild(string pid)
{
    string sqlexe = @"select * From proclass where pid=" + pid.ToString() + " order by [Order] ASC";
    DataTable dt = mdb.db.GetDataTable(sqlexe);
    return dt.Rows.Count > 0;
}
public bool IsReusable {
    get {
        return false;
    }
}

}

你看也能看明白，这就是一段select数据库的过程，知道这点，也该会了吧