day05 java JDBC案例—Android小白的学习笔记

1.要从键盘录入用户名与密码我们需要使用Scanner类完成操作

2.接收到用户名与密码后，我们需要调用jdbc程序根据用户名与密码查询数据库

User.java

package com.supergroup.domian;

public class User{
    private String id;
    private String usernasme;
    private String password;
    private String email;
    public User() {
        super();
    }
    public User(String id, String usernasme, String password, String email) {
        super();
        this.id = id;
        this.usernasme = usernasme;
        this.password = password;
        this.email = email;
    }
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public String getUsernasme() {
        return usernasme;
    }
    public void setUsernasme(String usernasme) {
        this.usernasme = usernasme;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    @Override
    public String toString() {
        return "User [id=" + id + ", usernasme=" + usernasme + ", password="
                + password + ", email=" + email + "]";
    }
    

}

Operation.java

package com.supergroup.operation;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import com.supergroup.domian.User;
import com.supergroup.utils.JDBCUtils;

public class Operation {
    public static User select(User user) throws ClassNotFoundException,
            SQLException {
        User result = null;
        Connection con = null;
        Statement st = null;
        ResultSet rs = null;
        // TODO Auto-generated method stub

        con = JDBCUtils.getConnection();
        PreparedStatement ps=con.prepareStatement("select * from user where username=? and password=?");
        ps.setString(1, user.getUsernasme());
        ps.setString(2, user.getPassword());
        rs=ps.executeQuery();

        if (rs.next()) {
            result = new User(rs.getString(1), rs.getString(2),
                    rs.getString(3), rs.getString(4));

        }
        JDBCUtils.closeAll(rs, st, con);

        return result;
    }

    public static User _select(User user) throws ClassNotFoundException,
            SQLException {
        User result = null;
        Connection con = null;
        Statement st = null;
        ResultSet rs = null;
        // TODO Auto-generated method stub

        con = JDBCUtils.getConnection();
        st = con.createStatement();
        rs = st.executeQuery("select * from user where username='"
                + user.getUsernasme() + "'and password ='" + user.getPassword()
                + "'");
        if (rs.next()) {
            result = new User(rs.getString(1), rs.getString(2),
                    rs.getString(3), rs.getString(4));

        }
        JDBCUtils.closeAll(rs, st, con);

        return result;
    }

}

JDBCUtils.java

package com.supergroup.utils;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ResourceBundle;

public class JDBCUtils {
    private static String DRIVER;
    private static String URL;
    private static String UNAME;
    private static String PWD;
    static {
        ResourceBundle rb = ResourceBundle
                .getBundle("com.supergroup.utils.JDBC");
        DRIVER = rb.getString("DRIVER");
        URL = rb.getString("URL");
        UNAME = rb.getString("UNAME");
        PWD = rb.getString("PWD");

    }

    static {

        try {
            Class.forName(DRIVER);
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public static Connection getConnection() throws SQLException,
            ClassNotFoundException {
        // TODO Auto-generated method stub

        return DriverManager.getConnection(URL, UNAME, PWD);

    }

    public static void closeAll(ResultSet rs, Statement st, Connection con)
            throws SQLException {
        if (rs != null)
            rs.close();
        if (st != null)
            st.close();
        if (con != null)
            con.close();

    }

}

JDBC.properties

DRIVER=com.mysql.jdbc.Driver
URL=jdbc:mysql:///day06
UNAME=root
PWD=123456

View.java

package com.supergroup.view;

import java.sql.SQLException;
import java.util.Scanner;

import com.supergroup.domian.User;
import com.supergroup.operation.Operation;

public class View {

    public static void main(String[] args) throws ClassNotFoundException,
            SQLException {
        // TODO Auto-generated method stub
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入用户名");
        String uname = sc.nextLine();
        System.out.println("请输入密码");
        String pwd = sc.nextLine();
        User user = new User(null, uname, pwd, null);
        user = Operation.select(user);
        if (user == null) {
            System.err.println("登录失败");

        } else {
            System.out.println("登录成功");
            System.out.println(user);
        }

    }

}
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