[Java] 利用sql實作註冊登入範例

基本資料庫連線的方式在上一篇文章:[Java] 連線至sql資料庫

 
1. IPaddress:統一數值方便取用,建一個interface


 

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    public interface IPaddress {
    final String ip = "IP地址";
    final String sqldbaccount = "使用者名稱";
    final String sqldbpass = "使用者密碼";
    final String dbName = "資料庫名稱";
}
 
 
Register.java,要使用時先new一個Register object,再呼叫此object的insertTable即可
 
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import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
 
public class Register implements IPaddress{
    private Connection connection = null;
    private Statement statement = null;
    private ResultSet resultSet = null;
    private PreparedStatement pStatement = null;
    private String dropdbSQL = "DROP TABLE User "
    private String name;
    private String passwd;
    private String nickName;
     
    //建構子,初始化要註冊的資料,並與資料庫取得連線
    public Register(String name, String nickName, String passwd){
        this.name = name;
        this.passwd = passwd;
        this.nickName = nickName;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            connection = DriverManager.getConnection("jdbc:mysql://"+ip+"/"+dbName+"?useUnicode=true&characterEncoding=Big5",
            sqldbaccount,sqldbpass);
        } catch (ClassNotFoundException e) {
            //System.out.println(e);
        }catch (SQLException e) {
            //System.out.println(e);
        }
    }
 
    public int insertTable(){
        int confirm = selectTable();//先去資料表查使用者名稱有無重複
        int flag = 0;
        String insertdbSQL = "insert into User(id,name,nickName, passwd) " +
          "select ifNULL(max(id),0)+1,?,?,? FROM User";
        try {
            if (confirm==0) {//沒有重複使用者
                pStatement = connection.prepareStatement(insertdbSQL);
                pStatement.setString(1, name);
                pStatement.setString(2, nickName);
                pStatement.setString(3, passwd);
                pStatement.executeUpdate();
                creatTable_friend();
                creatTable_chat();
                flag = 1;
            }
        } catch (SQLException e) {
            //System.out.println(e);
        }finally{
            closedb();
        }
        return flag;//成功註冊回傳1
    }
     
    public int selectTable(){
        String selectSQL = "select * from User ";
        int flag = 0;
        try {
            statement = connection.createStatement();
            resultSet = statement.executeQuery(selectSQL);
            while (resultSet.next()) {
                 if (resultSet.getString("name").equals(name))
                     flag = 1;
            }
        } catch (SQLException e) {
            //System.out.println("selectTable:"+e);
        }finally{
            closedb();
        }
        return flag;//有重複使用者回傳1
    }
     
    public void closedb(){
        try {
            if (resultSet!=null){
                resultSet.close();
                resultSet = null;
            }
            if (statement != null) {
                statement.close();
                statement = null;
            }
            if (pStatement != null) {
                pStatement.close();
                pStatement = null;
            }
        } catch (SQLException e) {
            //System.out.println(e);
        }
    }
     
}
 
Login.java ,要使用時先new 一個Login object ,再呼叫此object的selectTable method即可
 
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import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
 
public class Login implements IPaddress{
    private Connection connection = null;
    private Statement statement = null;
    private ResultSet resultSet = null;
    private PreparedStatement pStatement = null;
    private String name;
    private String passwd;
     
     
    public Login(String name,String passwd){
        this.name = name;
        this.passwd = passwd;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            connection = DriverManager.getConnection("jdbc:mysql://"+ip+"/"+dbName+"?useUnicode=true&characterEncoding=Big5",
            sqldbaccount,sqldbpass);
        } catch (ClassNotFoundException e) {
            //System.out.println(e);
        }catch (SQLException e) {
            //System.out.println(e);
        }
    }
     
    public int selectTable(){
        String selectSQL = "select * from User ";
        int flag = 0;
        try {
            statement = connection.createStatement();
            resultSet = statement.executeQuery(selectSQL);
            while (resultSet.next()) {//如果使用者名稱和密碼都正確
                if (resultSet.getString("name").equals(name)&&resultSet.getString("passwd").equals(passwd)){
                    flag = 1;
                }
            }
        } catch (SQLException e) {
            //System.out.println("selectTable:"+e);
        }finally{
            closedb();
        }
        return flag;
    }
     
    public void closedb(){
        try {
            if (resultSet!=null){
                resultSet.close();
                resultSet = null;
            }
            if (statement != null) {
                statement.close();
                statement = null;
            }
            if (pStatement != null) {
                pStatement.close();
                pStatement = null;
            }
        } catch (SQLException e) {
            //System.out.println(e);
        }
    }
     
}
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