Simple ways to operate MySQL: Statement, PreparedStatement

(1) mysql-connected tool class: Dbutil.java

 PackageCom.xuliugen.util;ImportJava.sql.Connection;ImportJava.sql.DriverManager;ImportJava.sql.PreparedStatement;ImportJava.sql.ResultSet;ImportJava.sql.SQLException;ImportJava.sql.Statement; Public  class dbutil {     Public StaticConnectionGetconn() {Connection conn =NULL;Try{Class.forName ("Com.mysql.jdbc.Driver"); conn = Drivermanager.getconnection ("jdbc:mysql://localhost:3306/Your database name","Your account","Your password"); }Catch(ClassNotFoundException e)        {E.printstacktrace (); }Catch(SQLException e)        {E.printstacktrace (); }returnConn } Public StaticPreparedStatementpreparestmt(Connection conn, String SQL) {PreparedStatement pstmt =NULL;Try{pstmt = conn.preparestatement (sql); }Catch(SQLException e)        {E.printstacktrace (); }returnpstmt; } Public StaticResultSetExecuteQuery(Statement stmt, String sql) {ResultSet rs =NULL;Try{rs = stmt.executequery (SQL); }Catch(SQLException e)        {E.printstacktrace (); }returnRs } Public Static void Close(Connection conn, Statement stmt, PreparedStatement prestatement, ResultSet rs) {if(Conn! =NULL) {Try{Conn.close (); }Catch(SQLException e)            {E.printstacktrace (); } conn =NULL; }if(stmt! =NULL) {Try{Stmt.close (); }Catch(SQLException e)            {E.printstacktrace (); } stmt =NULL; }if(Prestatement! =NULL) {Try{Prestatement.close (); }Catch(SQLException e)            {E.printstacktrace (); } prestatement =NULL; }if(rs! =NULL) {Try{Rs.close (); }Catch(SQLException e)            {E.printstacktrace (); } rs =NULL; }    }}

(2) database for inserting data using PreparedStatement:

 Public Boolean savecomment(Comment Comment)        {Connection Connection = Dbutil.getconn (); String sql ="INSERT into comment values (null,?,?,?,?)"; PreparedStatement PreparedStatement =NULL;BooleanFlag =false;Try{preparedstatement = connection.preparestatement (sql); Preparedstatement.setstring (1, Comment.getcommenttext () +""); Preparedstatement.setstring (2, Comment.getcommenttime () +""); Preparedstatement.setstring (3, Comment.getuserid () +""); Preparedstatement.setstring (4, Comment.getarticleid () +"");intIsOk = Preparedstatement.executeupdate ();if(IsOk >0) {return!flag; }Else{returnFlag }        }Catch(SQLException e)        {E.printstacktrace (); } dbutil.close (Connection,NULL, PreparedStatement,NULL);returnFlag }

(3) Use PreparedStatement to select data and read data:

 PublicList<comment>Getcommentdetail(intUseridintArticleID) {Connection Connection = Dbutil.getconn (); String sql ="SELECT * from comment C where c.userid=?" and c.articleid=? ";//write SQL statements, the first field does not need to be inserted, is automatically addedPreparedStatement PreparedStatement =NULL; List<comment> commentlist =NewArraylist<comment> ();Try{preparedstatement = connection.preparestatement (sql); Preparedstatement.setint (1, UserID); Preparedstatement.setint (2, ArticleID);//There is no need for incoming SQL statements in the productionResultSet rs = Preparedstatement.executequery ();//Determine if it is empty            if(Rs.next ()) { while(Rs.next ()) {//Iterate the information into the listComment Comment =NewComment (); Comment.setcommentid (Rs.getint ("Commentid")); Comment.setcommenttext (Rs.getstring ("Commenttext")); Comment.setcommenttime (Rs.getstring ("Commenttime")); Comment.setuserid (Rs.getint ("userid")); Comment.setarticleid (Rs.getint ("ArticleID"));                Commentlist.add (comment); }            }Else{return NULL; }        }Catch(SQLException e)        {E.printstacktrace (); } dbutil.close (Connection,NULL, PreparedStatement,NULL);returnCommentlist; }

(4) using statement to operate the database:

 PublicList<article>Getarticlemessage() {Connection Connection = Dbutil.getconn (); String sql ="SELECT * from article";//write SQL statements, the first field does not need to be inserted, is automatically addedStatement Statement =NULL; List<article> articlelist =NewArraylist<article> ();Try{statement = Connection.createstatement (); ResultSet rs = statement.executequery (SQL);//Determine if it is empty            if(Rs.next ()) { while(Rs.next ()) {//Iterate the information into the listArticle Article =NewArticle (); Article.settitle (Rs.getstring ("title")); Article.setcontext (Rs.getstring ("Context")); Article.setarticletime (Rs.getstring ("Articletime")); Article.setuserid (Rs.getint ("userid")); Article.setarticleid (Rs.getint ("ArticleID"));                Articlelist.add (article); }            }Else{return NULL; }        }Catch(SQLException e)        {E.printstacktrace (); } dbutil.close (connection, statement,NULL,NULL);returnArticlelist; }

Simple ways to operate MySQL: Statement, PreparedStatement