Big Data Java Foundation 21st day Job

Tag:java   mysql    Big Data    

First question: Use Preparedstament to MySQL for crud operations. create table  ' Edu_user '   (   ' user_id '  int (Ten)  unsigned not null  AUTO_INCREMENT COMMENT  ' User ID ',   ' user_name '  varchar ()  not null  DEFAULT  '  COMMENT  ' username ',   ' user_age '  tinyint (3)  unsigned not  NULL DEFAULT  ' 0 '  COMMENT  ' User age ',  primary key  (' user_id '))   engine=innodb default charset=utf8 comment= ' user table ';p ublic class datademo {     public static void main (String[] args)  throws exception {         db db = new db ();         db. InsertData ();         db. DeleteData ();         db. UpdateData ();          db. Selectdata ();    }}import java.sql.connection;import java.sql.drivermanager; import java.sql.preparedstatement;import java.sql.resultset;public class db {     private connection conn;    public db () {         try {             class.forname ("Com.mysql.jdbc.Driver");             String url =  "Jdbc:mysql://localhost:3306/edu_index";             String username =  "Root";             String password =  "Jiangmin";             this.conn = drivermanager.getconnection ( url, username, p assword);         }catch (exception e) {             e.printstacktrace ();         }    }        public void  InsertData ()  throws exception{        string sql =   "Insert into edu_user (user_id,user_name,user_age)  values (?,?,?)"  ;        PreparedStatement ppst =  Conn.preparestatement (SQL);         ppst.setint (1, 1);         ppst.setstring (2,  "Tomas");         ppst.setint (3, 10);         ppst.execute ();     }        publIc void deletedata ()  throws Exception{         string sql=  "DELETE FROM EDU_USER WHERE USER_ID = ?"  ;        PreparedStatement ppst =  Conn.preparestatement (SQL);         ppst.setint (1, 1);         ppst.execute ();    }         public void updatedata ()  throws Exception{         String sql=  "Update edu_user set user_age = ?,user_name  = ? where user_id = ? "  ;        PreparedStatement ppst =  Conn.preparestatement (SQL);         ppst.setint (1, 100);     &Nbsp;   ppst.setstring (2,  "Aron");         Ppst.setint (3, 1);         ppst.execute ();     }        public void selectdata ()  throws Exception {        string sql=  "Select user_id,user_name,user_age  from edu_user where user_id = ? "  ;        PreparedStatement ppst =  Conn.preparestatement (SQL);         ppst.setint (1, 1);         ppst.execute ();         resultset  rs = ppst.getresultset ();         while (Rs.next ()) {             string usEr_id = rs.getstring ("user_id");             string user_name = rs.getstring ("user_name");             string user_age = rs.getstring ("User_age");             system.out.println ("user_id = "  +  user_id +  ",user_name = "  + user_name +  ",user_age = "   + user_age);         }    }}

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Big Data Java Foundation 21st day Job