Java使用jdbc连接MySql数据库，实现增删改查

首先，导入MySql连接数据库的jar包，我用的是

mysql连接jar包

import java.sql.DriverManager;
import java.sql.SQLException;
import com.mysql.jdbc.Connection;

public class DB {
    //数据库的URL
    private static final String URL="jdbc:mysql://127.0.0.1:3306/test";
    //数据库连接的用户名
    private static final String USER="root";
    //密码
    private static final String PASSWORD="123456";
    private static Connection conn=null;
    static {
        try {
            //加载驱动程序
            Class.forName("com.mysql.jdbc.Driver");
            //获得数据库的连接
            conn=(Connection) DriverManager.getConnection(URL, USER, PASSWORD);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
    
    public static Connection getConnection(){
        return conn;
    }
}

实体类Users：

public class Users {
    private int id;
    private String username;
    private String password;
    public Users() {
        super();
    }
    public int getId() {
        return id;
    }
    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 Users(String username, String password) {
        this.username = username;
        this.password = password;
    }
}

数据库操作类UsersDao，实现users的增删改查操作

import java.sql.ResultSet;
import java.sql.SQLException;
import com.mysql.jdbc.Connection;
import com.mysql.jdbc.PreparedStatement;
//导入刚才的两个类
import cn.jufe.sex.db.DB;
import cn.jufe.sex.model.Users;

public class UsersDao {
    public boolean addUser(Users user) throws SQLException{
    //增加用户,传入一个users对象，将对象中的数据加入数据库
    //id属性我在数据中设置了自增长型，所以ID不用去设置
        //获得数据库连接
        Connection conn = DB.getConnection();
        //sql语句
        String sql ="insert into users(username,password) "+ "values(?,?)";
        //通过conn获得PreparedStatement对象，该对象可对sql语句进行预编译
        PreparedStatement ptmt = (PreparedStatement) conn.prepareStatement(sql);
        //对sql语句中的参数进行赋值
        ptmt.setString(1, user.getUsername());
        ptmt.setString(2, user.getPassword());
        //执行SQL语句,返回受影响的行数，a大于0，则成功
        int a = ptmt.executeUpdate();
        if(a>0)
           return true;
        else
           return false;
    }
    public boolean deluser(Integer id) throws SQLException{//删
        //获得数据库连接
        Connection conn = DB.getConnection();
        //sql语句
        String sql ="delete from users where id=?";
        //通过conn获得PreparedStatement对象，该对象可对sql语句进行预编译
        PreparedStatement ptmt = (PreparedStatement) conn.prepareStatement(sql);
        ptmt.setInt(1, id);
        //执行SQL语句,返回受影响的行数，a大于0，则成功
        int a = ptmt.executeUpdate();
        if(a>0)
           return true;
        else
           return false;
    }
    public boolean updateuser(Users user) throws SQLException{//改
        //获得数据库连接
        Connection conn = DB.getConnection();
        //sql语句
        String sql =" update users set name=?,password=? where id=?";
        //通过conn获得PreparedStatement对象，该对象可对sql语句进行预编译
        PreparedStatement ptmt = (PreparedStatement) conn.prepareStatement(sql);
        ptmt.setString(1, u.getName());
        ptmt.setString(2, u.getPassword());
        ptmt.setString(3, u.getId());
        //执行SQL语句,返回受影响的行数，a大于0，则成功
        int a = ptmt.executeUpdate();
        if(a>0)
           return true;
        else
           return false;
    }
    public Users findByName(String username) throws SQLException{
    //通过姓名查询用户，通过ID同理
        //获得数据库连接
        Connection conn=DB.getConnection();
        //sql语句
        String sql="select * from users where username=?";
        //通过conn获得PreparedStatement对象，该对象可对sql语句进行预编译
        PreparedStatement ptmt=(PreparedStatement) conn.prepareStatement(sql);
        ptmt.setString(1, username);
        //new一个Resultset对象接受返回的数据
        ResultSet rs=ptmt.executeQuery();
        //通过users对象接受rs中的数据，如果rs中含有多个数据则使用数组接收
        //while(rs.next()) {
        //  Users user=new Users();
        //  user.setPassword(rs.getString("password"));
        //  user.setUsername(rs.getString("username"));
        //  list.add(user);
        //}
        //  return list;
        while(rs.next()) {
            Users user=new Users();
            user.setPassword(rs.getString("password"));
            user.setUsername(rs.getString("username"));
        }
        return user;
    }
}

UsersDao的使用，直接new一个UsersDao对象，调用函数即可