Shulou(Shulou.com)06/01 Report--

Truncate table table name

Delete all the data in the table directly. Unlike delete, this method cannot be selected using where, and can only be deleted.

Truncate table users

Java connection to the database:

Package com.edu.gkh

Import java.sql.Connection

Import java.sql.DriverManager

Import java.sql.ResultSet

Import java.sql.Statement

Import java.util.Scanner

Public class Homework {

Static Statement sc=null

Static Scanner sca=new Scanner (System.in)

Static String username

Public static void main (String [] args) throws Exception {

GetStatement ()

String name2= ""

String pwd2= ""

For (;;) {

System.out.println ("Please enter a registered account")

String name=sca.next ()

System.out.println ("Please enter password")

String pwd=sca.next ()

System.out.println ("Please enter your password again")

String pwd1=sca.next ()

If (pwd1.equals (pwd)) {

Name2=name

Pwd2=pwd

System.out.println ("registered successfully")

Break

}

Else {

System.out.println ("two passwords are not the same, please re-enter; whether to re-register yes/no")

Char regist=sca.next () .charAt (0)

If (regist=='y') {

System.out.println ("please re-enter")

}

Else if (regist=='n') {

System.out.println ("you have unregistered")

}

Else {

System.out.println ("illegal input")

}

}

}

System.out.println ("Welcome to J18 Bank")

System.out.println ("Please log in:")

System.out.println ("user name:")

Username=sca.next ()

System.out.println ("password:")

String password=sca.next ()

Int num=queryAccount (username,password)

If (num==1) {

System.out.println ("login succeeded")

For (;;) {

System.out.println ("Please select transaction type:")

System.out.println ("1, deposit 2, withdraw 3, query balance")

Int cz=sca.nextInt ()

If (cz==1) {

Cun ()

} else if (cz==2) {

Qu ()

} else if (cz==3) {

Query ()

} else {

System.out.println ("Thank you for using")

Break

}

}

} else {

System.out.println ("login failed")

}

}

Public static void cun () throws Exception {

System.out.println ("Please enter your deposit amount:")

Double money=sca.nextDouble ()

String sql= "update account set money=money+" + money

Boolean a=sc.execute (sql)

If (! a) {

System.out.println ("deposit is successful!")

}

}

Public static void qu () throws Exception {

System.out.println ("Please enter your withdrawal amount:")

Double money=sca.nextDouble ()

String sql= "update account set money=money-" + money

System.out.println (sql)

Boolean a=sc.execute (sql)

If (! a) {

System.out.println ("withdrawal successful!")

}

}

Public static int queryAccount (String username,String password) throws Exception {

String sql= "select * from account where aname='" + username+ "'and apwd='" + password+ "'"

ResultSet rs=sc.executeQuery (sql)

Int num=0

While (rs.next ()) {

Num++

}

Return num

}

Public static void query () throws Exception {

String sql= "select money from account where aname='" + username+ "'"

ResultSet rs=sc.executeQuery (sql)

Double money=0

While (rs.next ()) {

Money=rs.getDouble (1)

}

System.out.println ("your account balance:" + money)

}

Public static void getStatement () throws Exception {

Class.forName ("com.mysql.jdbc.Driver")

String url= "jdbc:mysql://localhost:3306/atm"

String username= "root"

String password= "root"

Connection c=DriverManager.getConnection (url,username,password)

Sc=c.createStatement ()

}

}

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