在IDEA上实现简单的JDBC增删查改操作

在IDEA上实现简单的JDBC增删查改操作

在今天的学习里，学到了如何完成简单的增删查改操作，在这里撰写一篇文章以便自己整理回忆。

首先要定义一些字符串。

    //数据库连接地址
    private static final String URL = "Jdbc:mysql://localhost:3306/test?serverTimezone=GMT";
    //用户名
    private static final String USER_NAME = "root";
    //密码
    private static final String PASSWORD = "root";

这是一个对应数据表的bean类。

public class Test {
    public Test(int id, int password) {
        this.id = id;
        this.password = password;
    }

    private int id;
    private int password;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public int getPassword() {
        return password;
    }

    public void setPassord(int passord) {
        this.password = passord;
    }

    @Override
    public String toString() {
        return "Test{" +
                "id=" + id +
                ", passord=" + password +
                '}';
    }
}

获得数据库连接，将其封装成函数，后续直接调用函数即可实现连接。

public static Connection getConnection(){
        Connection connection=null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            connection = DriverManager.getConnection(URL, USER_NAME, PASSWORD);
        } catch (Exception e) {
            e.printStackTrace();
        }

        return connection;
    }
  

插入数据

public static void insert(Test test){
        Connection connection = DBUtil.getConnection();
        String sql="insert into test (id,password) values(?,?)";
        try {
            PreparedStatement prst =connection.prepareStatement(sql);
            prst.setInt(1, test.getId());
            prst.setInt(2, test.getPassword());
            prst.executeUpdate();
            prst.close();
            connection.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

删除数据

public static void delete(int id){
        Connection connection = DBUtil.getConnection();
        String sql = "delete from test where id='" + id + "'";
        try {
            PreparedStatement prst =connection.prepareStatement(sql);
            prst.executeUpdate();
            prst.close();
            connection.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

查询数据

public List findAll() {
        List list = new ArrayList<>();
        Connection connection = null;
        PreparedStatement prst = null;
        ResultSet rs = null;
        try {

            connection = DBUtil.getConnection();

            String sql = "SELECT * FROM test";

            prst = connection.prepareStatement(sql);

            rs = prst.executeQuery();
            while (rs.next()) {
                int id = rs.getInt(1);
                int password = rs.getInt(2);
                Test test = new Test(id, password);
                list.add(test);
            }
            System.out.println(list.toString());

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            DBUtil.closeConnetion(rs, prst, connection);
        }
        return list;
    }

修改数据

public static void update(Test test){
        Connection connection = DBUtil.getConnection();
        String sql = "update students set password='" + test.getPassword() + "' where id='" + test.getId() + "'";
        try {
            PreparedStatement prst =connection.prepareStatement(sql);
            prst.executeUpdate();
            prst.close();
            connection.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

关闭资源

public static void closeConnetion(ResultSet rs, PreparedStatement prst,Connection connection){
        if (rs != null) {
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }if (prst != null) {
            try {
                prst.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (connection != null) {
            try {
                connection.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

这样在主函数里调用各部分函数，即可完成简单的增删查改操作了！