Java connection MySQL database additions and deletions change operation record

1. Connect to database and get database connection variables

Note When connecting to the database

(1) Open DB Browser New database Driver, note add Driver jars Add the package, my is Mysql-connector-java-5.0.3-bin.jar

(2) To copy the database jar package to the Web-inf\lib under the project

 import Java.sql.connection;//java Package public class DBConnection {               Private String dbdriver= "Com.mysql.jdbc.Driver";              private string Dburl= "Jdbc:mysql://[ip address]:[port number/[database name]";//Change the private string dbuser= "root" according to the actual situation;              Private String dbpass= "root";                  Public Connection Getconn () {Connection conn=null;                  try {class.forname (dbdriver);                  } catch (ClassNotFoundException e) {e.printstacktrace (); try {conn = drivermanager.getconnection (dburl,dbuser,db Pass);//Note is a three parameter} catch (SQLException e) {E.print                  StackTrace ();              } return conn; }          }  

2. Insert Operation

    public int Insert ()      {          int i=0;          String sql= "INSERT into (table name) (column name 1, listing 2) VALUES (?,?)";          Connection cnn=getconn ();                try{              preparedstatement prestmt =cnn.preparestement (SQL);              Prestmt.setstring (1, value);              Prestmt.setstring (2, value);//or: Prestmt.setint (1, value);              I=prestmt.executeupdate ();          }          catch (SQLException e)          {              e.printstacktrace ();          }          Return i;//returns the number of rows affected, 1 for execution success      }  

3. Update Operations

    public int update      {          int i=0;          String sql= "Update (table name) set  (column name 1) =?, List 2=? where (column name) =? ";//note to have a where condition          Connection cnn=getconn ();                      try{              preparedstatement prestmt =cnn.preparestatement (SQL);              Prestmt.setstring (1, (value));              Prestmt.setstring (2, (value));//or: Prestmt.setint (1, value);              Prestmt.setint (3, (value));              I=prestmt.executeupdate ();          }          catch (SQLException e)          {              e.printstacktrace ();          }          Return i;//returns the number of rows affected, 1 for execution success      }  

4. Find Operations

    Public String Select          {              String sql = ' SELECT * FROM (table name) where (column name) = (value) ";              Connection CNN = Getconn ();//Here for the method written by yourself Getconn () Get the connection              try              {                  Statement stmt = Conn.createstatement ();                  ResultSet rs = stmt.executequery (sql);                        if (Rs.next ())                  {                      int m1 = Rs.getint (1),//or rs.getstring (1), based on the value type of the column in the database, the parameter is the first column of                      String m2 = Rs.getstring (2);                  }                  You can write the found value to the class and return the corresponding object              }              catch (SQLException e)              {                  e.printstacktrace ();              }              Return (the variable of the corresponding value);          }  

5. Delete Operation

    public int Delete ()      {          String sql = ' Delete from (table name) where (column name) = (value) ";          int i=0;          Connection conn = Getconn ();//Here for the method written by yourself Getconn () Get the connection          try          {              Statement stmt = Conn.createstatement ();              i = stmt.executeupdate (sql);          }          catch (SQLException e)          {              e.printstacktrace ();          }          Return i;//If the return is 1, the execution succeeds;      }  

Java connection MySQL database additions and deletions change operation record