Java message Management System in the case of fuzzy query sharing _java

This article shares a message management system based on Mvc+dao, including additions and deletions, which query, there are all inquiries and by keyword fuzzy query function, the specific contents are as follows
Notedao.java

Package Cn.mldn.lxh.note.dao; 
 
Import java.util.*; 
Import cn.mldn.lxh.note.vo.*; 
 
Public interface Notedao 
{ 
  //Add operation public 
  void Insert (note) throws Exception; 
  Modify operation public 
  void Update (note) throws Exception; 
  Delete operation public 
  void Delete (int id) throws Exception; 
  Query by ID, mainly for updates using public note 
  Querybyid (int id) throws Exception; 
  Query all public 
  List Queryall () throws Exception; 
  Fuzzy query public 
  List querybylike (String cond) throws Exception; 
 

Notedaoimpl.java

Package Cn.mldn.lxh.note.dao.impl; 
Import java.sql.*; 
Import java.util.*; 
Import cn.mldn.lxh.note.vo.*; 
Import cn.mldn.lxh.note.dao.*; 
 
Import cn.mldn.lxh.note.dbc.*; public class Notedaoimpl implements Notedao {//Add operations public void Insert (note) throws Exception {Stri 
    ng sql = "INSERT into the note (id,title,author,content) VALUES (Note_sequ.nextval,?,?,?)"; 
    PreparedStatement pstmt = null; 
    DatabaseConnection DBC = null; 
    DBC = new DatabaseConnection (); 
      try {pstmt = Dbc.getconnection (). preparestatement (SQL); 
      Pstmt.setstring (1,note.gettitle ()); 
      Pstmt.setstring (2,note.getauthor ()); 
      Pstmt.setstring (3,note.getcontent ()); 
      Pstmt.executeupdate (); 
    Pstmt.close (); 
      catch (Exception e) {//System.out.println (e); throw new Exception ("An error occurred in the operation!!! 
    ") ; 
    finally {dbc.close (); }///modify operation public void update throws Exception {String sql = UPDATE Note SET title=?,author=?,content=? 
    WHERE id=? "; 
    PreparedStatement pstmt = null; 
    DatabaseConnection DBC = null; 
    DBC = new DatabaseConnection (); 
      try {pstmt = Dbc.getconnection (). preparestatement (SQL); 
      Pstmt.setstring (1,note.gettitle ()); 
      Pstmt.setstring (2,note.getauthor ()); 
      Pstmt.setstring (3,note.getcontent ()); 
      Pstmt.setint (4,note.getid ()); 
      Pstmt.executeupdate (); 
    Pstmt.close (); An error occurred in the catch (Exception e) {throw new Exception ("Operation")!!! 
    ") ; 
    finally {dbc.close (); 
    }//delete operation public void delete (int id) throws Exception {String sql = ' Delete from note WHERE id=? '; 
    PreparedStatement pstmt = null; 
    DatabaseConnection DBC = null; 
    DBC = new DatabaseConnection (); 
      try {pstmt = Dbc.getconnection (). preparestatement (SQL); 
      Pstmt.setint (1,id); Pstmt.executeupdate () ; 
    Pstmt.close (); An error occurred in the catch (Exception e) {throw new Exception ("Operation")!!! 
    ") ; 
    finally {dbc.close (); 
    }///by ID query, mainly for update using public note Querybyid (int id) throws Exception {note = null; 
    String sql = "Select id,title,author,content from WHERE id=?"; 
    PreparedStatement pstmt = null; 
    DatabaseConnection DBC = null; 
    DBC = new DatabaseConnection (); 
      try {pstmt = Dbc.getconnection (). preparestatement (SQL); 
      Pstmt.setint (1,id); 
      ResultSet rs = Pstmt.executequery (); 
        if (Rs.next ()) {note = new note (); 
        Note.setid (Rs.getint (1)); 
        Note.settitle (rs.getstring (2)); 
        Note.setauthor (Rs.getstring (3)); 
      Note.setcontent (Rs.getstring (4)); 
      } rs.close (); 
    Pstmt.close (); An error occurred in the catch (Exception e) {throw new Exception ("Operation")!!! 
    ") ; finally {DBC.CLose (); 
  } return note; 
    //Query All public List Queryall () throws Exception {List all = new ArrayList (); 
    String sql = "Select id,title,author,content from note"; 
    PreparedStatement pstmt = null; 
    DatabaseConnection DBC = null; 
    DBC = new DatabaseConnection (); 
      try {pstmt = Dbc.getconnection (). preparestatement (SQL); 
      ResultSet rs = Pstmt.executequery (); 
        while (Rs.next ()) {The note Note = The new note (); 
        Note.setid (Rs.getint (1)); 
        Note.settitle (rs.getstring (2)); 
        Note.setauthor (Rs.getstring (3)); 
        Note.setcontent (Rs.getstring (4)); 
      All.add (note); 
      } rs.close (); 
    Pstmt.close (); 
      catch (Exception e) {System.out.println (e); throw new Exception ("An error occurred in the operation!!! 
    ") ; 
    finally {dbc.close (); 
  return all; 
  ///Fuzzy query public List querybylike (String cond) throws Exception{List all = new ArrayList (); String sql = "Select Id,title,author,content from WHERE is title like?" Or AUTHOR like? 
    Or CONTENT like? "; 
    PreparedStatement pstmt = null; 
    DatabaseConnection DBC = null; 
    DBC = new DatabaseConnection (); 
      try {pstmt = Dbc.getconnection (). preparestatement (SQL); 
      Pstmt.setstring (1, "%" +cond+ "%"); 
      Pstmt.setstring (2, "%" +cond+ "%"); 
      Pstmt.setstring (3, "%" +cond+ "%"); 
      ResultSet rs = Pstmt.executequery (); 
        while (Rs.next ()) {The note Note = The new note (); 
        Note.setid (Rs.getint (1)); 
        Note.settitle (rs.getstring (2)); 
        Note.setauthor (Rs.getstring (3)); 
        Note.setcontent (Rs.getstring (4)); 
      All.add (note); 
      } rs.close (); 
    Pstmt.close (); 
      catch (Exception e) {System.out.println (e); throw new Exception ("An error occurred in the operation!!! 
    ") ; 
    finally {dbc.close (); } return ALL 
 } 
};

Noteservlet.java

Package cn.mldn.lxh.note.servlet; 
Import java.io.*; 
Import javax.servlet.*; 
Import javax.servlet.http.*; 
Import cn.mldn.lxh.note.factory.*; 
 
Import cn.mldn.lxh.note.vo.*; public class Noteservlet extends HttpServlet {public void doget (HttpServletRequest request,httpservletresponse respon 
  SE) throws ioexception,servletexception {this.dopost (request,response); 
    } public void DoPost (HttpServletRequest request,httpservletresponse response) throws Ioexception,servletexception { 
    Request.setcharacterencoding ("GB2312"); 
    String Path = "errors.jsp"; 
    Receives the parameter value to be manipulated String status = Request.getparameter ("status"); 
        if (status!=null) {//parameter has content, then select the appropriate method//query all operations if ("SelectAll". Equals (status)) { 
        try {request.setattribute ("All", Daofactory.getnotedaoinstance (). Queryall ()); 
      catch (Exception e) {} path = "list_notes.jsp"; } 
      Insert Action if ("Insert". Equals (status)) {//1, receive inserted information String title = Request.getparam 
        Eter ("title"); 
        String author = request.getparameter ("author"); 
        String content = request.getparameter ("content"); 
        2, instantiate the Vo object note = The new note (); 
        Note.settitle (title); 
        Note.setauthor (author); 
        Note.setcontent (content); 
        3. Invoke DAO to complete the insert operation of the database Boolean flag = FALSE; 
          try {daofactory.getnotedaoinstance (). Insert (note); 
        Flag = true; 
        catch (Exception e) {} request.setattribute ("Flag", new Boolean (flag)); 
      Path = "insert_do.jsp"; 
        //By ID query operation, before you modify the data need to query out if ("Selectid". Equals (status)) {//receive parameter int id = 0; 
        try {id = integer.parseint (request.getparameter ("id")); 
       catch (Exception e) {} try {request.setattribute ("note", Daofactory.getnotedaoinstance (). Querybyid (ID)); 
      catch (Exception e) {} path = "update.jsp"; 
        }//Update operation if ("Update". Equals (status)) {int id = 0; 
        try {id = integer.parseint (request.getparameter ("id")); 
        catch (Exception e) {} String title = Request.getparameter ("title"); 
        String author = request.getparameter ("author"); 
        String content = request.getparameter ("content"); 
        Note = The new note (); 
        Note.setid (ID); 
        Note.settitle (title); 
        Note.setauthor (author); 
        Note.setcontent (content); 
        Boolean flag = false; 
          try {daofactory.getnotedaoinstance (). Update (note); 
        Flag = true; catch (Exception e) {} request.setattribute ("Flag", new Boolean (flag)); 
      Path = "update_do.jsp"; ///Fuzzy query if ("Selectbylike". Equals (status)) {String keyword = request.getparameter ("keyword 
        ") ; 
        try {request.setattribute ("All", Daofactory.getnotedaoinstance (). Querybylike (keyword)); 
      catch (Exception e) {} path = "list_notes.jsp"; 
        ///delete operation if ("Delete". Equals (status)) {//receive parameter int id = 0; 
        try {id = integer.parseint (request.getparameter ("id")); 
        catch (Exception e) {} Boolean flag = FALSE; 
          try {daofactory.getnotedaoinstance (). Delete (ID); 
        Flag = true; 
        catch (Exception e) {} request.setattribute ("Flag", new Boolean (flag)); 
      Path = "delete_do.jsp"; } else {/= no parameters, illegal client request} reqUest.getrequestdispatcher (Path). Forward (Request,response); 
} 
}; /* <servlet> <servlet-name>note</servlet-name> <servlet-class>cn.mldn.lxh.note.servlet.no teservlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>note</ 
 Servlet-name> <url-pattern>/note/note_mvc/Note</url-pattern> </servlet-mapping> *

List_notes.jsp

<%@ page contenttype= "text/html;charset=gb2312"%> <%@ page import= "java.util.*"%> <%@ page import= "CN.M" Ldn.lxh.note.vo.* "%>  

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