Xin's message board project ==== super-touched dbUtil implements the message board and message board dbutil
Message Board Management System
My completion:
After submission:
Basic Structure of my message board
Create a message board database:
At the beginning, I wrote a message form on the homepage:
<Body>Start to create a level in the background Java class
I first wrote an entity class in my entity layer to implement the added entity class.public class MessageBorad { private int id; private String message; private String author; private Date pastTime; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getMessage() { return message; } public void setMessage(String message) { this.message = message; } public String getAuthor() { return author; } public void setAuthor(String author) { this.author = author; } public Date getPastTime() { return pastTime; } public void setPastTime(Date pastTime) { this.pastTime = pastTime; }}Write the BaseDao tool class in my Dao Layer
Public class BaseDao {public static final String driver = "com. mysql. jdbc. driver "; public static final String url =" jdbc: mysql: // localhost: 3306/Database Name "; public static final String username =" root "; public static final String password = "1234"; public Connection con; public PreparedStatement ps; public ResultSet rs; static {Class. forname (driver);} public Connection getConnection () throws Exception {if (con = null | con. isClosed () {con = DriverManager. getConnection (url, username, password);} return con;} public void closeResources () throws Exception {rs. close (); ps. close (); con. close () ;}// execute add, delete, and modify public int exeuteUpdate (String SQL, Object... objs) throws Exception {con = getConnection (); ps = con. prepareStatement (SQL); for (int I = 0; I <objs. length; I ++) {ps. setObject (I + 1, objs [I]);} int count?ps.exe cuteUpdate (); return count ;}// obtain the result set ResultSet public ResultSet executeQuery (String SQL, Object... objs) throws Exception {con = getConnection (); ps = con. prepareStatement (SQL); for (int I = 0; I <objs. length; I ++) {ps = setObject (I + 1, objs [I]);} rs1_ps.exe cuteQuery (); return rs;} public int delete (int id) throws Exception {return 0 ;}}Write an implementation class in the Dao layer:
Public interface ImessageBorad {// all methods in my interface: public boolean addMessage (String message, String author, Date paseTime) throws Exception; // The pagination collection method public List <Object []> boradList (int pageIndex, int pageSize) throws Exception; // the total number of pages public int messageCount () throws Exception ;}Write an implementation class in my implementation package:
When using dbutil, add a jar package of dbutil, and connect the database to the jar package. The Jar package uploaded by the file is in the middle:Reference of my implementation class:
Start to write my class:
public class ImpMessageBorad implements ImessageBorad { con=bd.getConection(); DbUtils ut=new DbUtil(); QueryRunner qr=new QueryRunner(); BaseDao bd=new BaseBao(); ArrayListHandler al=new ArrayListHandler(); public boolean addMessage(String boradContent, String author, Date time) throws Exception { int num=qr.update(con,"insert into message(message,author,pastTime) values (?,?,?)",boradContent,author,DateTime); if(num>0){ flag=true; } ut.closeQuietly(con); } public List<Object[]> boradList(int pageIndex,int pageSize) throws Exception{ String sql="select * from message limit ?,?"; Object[] parameters={ (pageIndex)'; (pageSize); }; return qr.query(con,sql,parameters,al); }public int messageCount() throws Exception{ string sql="select count(1) as co from message"; int num=0; ResultSet rs=bd.executeQuery(sql); if(rs.next()){ num=rs.getInt("co"); } return num; }}Service is to call methods and implementations in my Dao Layer
Therefore, write my servlet to call the methods in my service:
// Solve the garbled problem first: ImessageBoradService msg = new MessageBoradServiceImp (); request. setCharacterEncoding ("UTF-8"); response. setCharacterEncoding ("UTF-8"); if ("da ". equest. getParameter ("action") {String boradContent = request. getParameter ("name"); String author = request. getParameter ("message"); Date dt = new Date (); try {if (msg. addMessage (boradContent, author, dt) {request. setAttribute ("success", "added successfully"); request. getRequestDispatcher ("/index. jsp "). forward (request, response);} else {request. setAttribute ("success", "failed to add"); request. getRequestDispatcher ("/index. jsp "). forward (request, response) ;}} catch (SQLException e) {// TODO Auto-generated catch block e. printStackTrace () ;}} int pageSize = 2; int pageIndex = 0; if ("ww ". equals (request. getParameter ("ca") {String index = request. getParameter ("pageIndex"); System. out. println (index); if (index. equals ("0") {pageIndex = pageIndex + pageSize;} else {System. out. println (2); int in = Integer. parseInt (index); pageIndex = in + pageSize; System. out. println (3) ;}} if ("ws ". equals (request. getParameter ("ca") {String index = request. getParameter ("pageIndex"); System. out. println (index); if (index. equals ("0") {pageIndex = 0;} else {int in = Integer. parseInt (index); pageIndex = in-pageSize ;}} request. setAttribute ("pageIndex", pageIndex); try {request. setAttribute ("list", msg. boradList (pageIndex, pageSize); request. getRequestDispatcher ("/index. jsp "). forward (request, response);} catch (SQLException e) {// TODO Auto-generated catch block e. printStackTrace ();}}}
In my front-end page, form:<H1> message board:
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