1.目录结构：

->con
—> DbHandle: 数据库操作把手
—> PropertiesUtil: 读取properties的操作
->config
---->config.properties：属性配置
->model
---->Admin:就是普通的model

2.properties配置属性：

# mysql config v5.7
db_connect = com.mysql.jdbc.Driver
db_url = localhost
db_port = 3306
db_name = db_java
db_username = root
db_password = 123456

3.PropertiesUtil.java:

package com;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Properties;

public class PropertiesUtil {
    private static Properties _prop = new Properties();
    
    public static void readProperties(){
        try {
            InputStream in = PropertiesUtil.class.getResourceAsStream("/config/config.properties");
            BufferedReader bf = new BufferedReader(new InputStreamReader(in));
            _prop.load(bf);
        }catch (IOException e){
            e.printStackTrace();
        }
    }

    
    public static String getProperty(String key){
        return _prop.getProperty(key);
    }
}

4.Admin.java ：

package model;

public class Admin {
    private String username;
    private String password;
    private String email;
    private String tel;
    private String time;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    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;
    }

    public String getTel() {
        return tel;
    }

    @Override
    public String toString() {
        return "{" +
                "username='" + username + '\'' +
                ", password='" + password + '\'' +
                ", email='" + email + '\'' +
                ", tel='" + tel + '\'' +
                ", time='" + time + '\'' +
                '}';
    }

    public void setTel(String tel) {
        this.tel = tel;
    }

    public String getTime() {
        return time;
    }

    public void setTime(String time) {
        this.time = time;
    }
}

5.DbHandle源码展示：

package com;

import model.Admin;

import java.sql.*;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

public class DbHandle {
    private String dbConnect;
    private String dbUrl;
    private String dbPort;
    private String dbName;
    private String dbUsername;
    private String dbPassword;

    private static Connection conn;  // 数据库连接对象
    private static Statement stmt;   // 数据库操作把柄对象

    public DbHandle() { // 加载配置文件
        PropertiesUtil.readProperties();
        this.dbConnect = PropertiesUtil.getProperty("db_connect");
        this.dbUrl = PropertiesUtil.getProperty("db_url");
        this.dbPort = PropertiesUtil.getProperty("db_port");
        this.dbName = PropertiesUtil.getProperty("db_name");
        this.dbUsername = PropertiesUtil.getProperty("db_username");
        this.dbPassword = PropertiesUtil.getProperty("db_password");
    }

    
    public Connection connect(){
        String DB_URL = "jdbc:mysql://"+this.dbUrl+":"+this.dbPort+"/"+this.dbName;
        try{
            // 注册 JDBC 驱动
            Class.forName(this.dbConnect);
            // 打开链接
            conn = DriverManager.getConnection(DB_URL, dbUsername, dbPassword);
            stmt = conn.createStatement();
        }catch(Exception e){
            e.printStackTrace();
            return null;
        }
        return conn;
    }

    
    public List<Admin> selectAll(){
        Connection con = this.connect();
        String sql = "select * from `admin`";
        List<Admin> list = new ArrayList<Admin>();
        try{
            stmt = con.createStatement();
            ResultSet rs = stmt.executeQuery(sql);
            while(rs.next()){
                Admin admin = new Admin();
                admin.setUsername(rs.getString("username"));
                admin.setPassword(rs.getString("password"));
                admin.setEmail(rs.getString("email"));
                admin.setTel(rs.getString("tel"));
                admin.setTime(rs.getTimestamp("time").toString());

                list.add(admin);
            }
        }catch (SQLException e){
        } catch (NullPointerException e){
        }finally {
            try {con.close();}catch (SQLException e){ }
            try {stmt.close();}catch (SQLException e){ }
        }
        return list;
    }

    
    public Boolean add(Admin user){
        String sql = "INSERT INTO `admin`\n" +
                     "(username, `password`, email, tel, time)\n" +
                     "VALUES\n" +
                     "(?,?,?,?,?)";
        Connection con = this.connect();
        PreparedStatement pstmt = null;

        try {
            pstmt = con.prepareStatement(sql);
            pstmt.setString(1, user.getUsername());
            pstmt.setString(2, user.getPassword());
            pstmt.setString(3, user.getEmail());
            pstmt.setString(4, user.getTel());
            pstmt.setTimestamp(5, new Timestamp(new Date().getTime()));
            int bool = pstmt.executeUpdate();
            if(bool == 1){
                return true;
            }else{
                return false;
            }
        }catch(SQLException e) {
            e.printStackTrace();
            return false;
        }finally {
            try {con.close();}catch (SQLException e){ }
            try { pstmt.close(); }catch (SQLException e){ }
        }
    }

    
    public Admin selectOfkeyAndValue(String key, String value){
        Admin admin = null;
        Connection con = this.connect();
        String sql = "select * from `admin` where "+key+" = '"+value+"'";
        try{
            stmt = con.createStatement();
            ResultSet rs = stmt.executeQuery(sql);
            while(rs.next()){
                admin = new Admin();
                admin.setUsername(rs.getString("username"));
                admin.setPassword(rs.getString("password"));
                admin.setEmail(rs.getString("email"));
                admin.setTel(rs.getString("tel"));
                admin.setTime(rs.getTimestamp("time").toString());
            }
            return admin;
        }catch (SQLException e) {
            e.printStackTrace();
        }finally {
            try {con.close();}catch (SQLException e){ }
            try {stmt.close();}catch (SQLException e){ }
        }
        return null;
    }
    

// public static void main(String[] args) {
// DbHandle db = new DbHandle();
// Admin t1 = db.selectOfkeyAndValue("username", "admin");
// System.out.println(t1.toString());
// }
}

6.关于：

转载请声明出处！