Java prepareStatement 学习

学习Java，使用PreparedStatement实现到MySQL数据库的增删改查操作。作为测试项目，按照实际的MVC架构实现目录部署

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项目已经share到 GitHub，有需要的可以clone测试。希望通过实际的编写代码能提高自己的编程能力

工程目录结构：

image.png

插入数据

public boolean addUser(Users users){
        boolean bool = false;
        conn = DbConn.getconn();
        String sql = "insert into test_users(nickname, username, password, sex) values(?,?,?,?)";

        try {
            pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, users.getNickname());
            pstmt.setString(2, users.getUsername());
            pstmt.setString(3, users.getPassword());
            pstmt.setInt(4, users.getSex());

            int rs = pstmt.executeUpdate();
            if (rs > 0){
                bool = true;
            }
        }catch (SQLException e){
            e.printStackTrace();
        }finally {
            DbClose.addClose(pstmt, conn);
        }

        return bool;
    }

查询

public String getUsers(Users users){
        String result = null;
        conn = DbConn.getconn();
        String sql = "select * from test_users where username = ?";
        try {
            pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, users.getUsername());


            ResultSet rs = pstmt.executeQuery();
            while (rs.next()) {
                result = "the user information is: " + rs.getString("nickname");
                System.out.println(result);
            }


        }catch (SQLException e){
            e.printStackTrace();
        }finally {
            DbClose.addClose(pstmt, conn);
        }

        return result;
    }

更新

public boolean updatePasswd(Users user){
        boolean bool = false;
        Connection conn = DbConn.getconn();
        String updatePasswd = "update test_users set password = ? where username = ?";
        try {
            pstmt = conn.prepareStatement(updatePasswd);
            pstmt.setString(1, user.getPassword());
            pstmt.setString(2, user.getUsername());
            int rs = pstmt.executeUpdate();
            if (rs > 0){
                bool = true;
                System.out.println("update password successfully!");
            }
        }catch (SQLException e) {
            e.printStackTrace();
        }finally {
            DbClose.addClose(pstmt, conn);
        }
        return  bool;
    }

删除

public  boolean deleteUsers(Users users){
        boolean bool = false;
        conn = DbConn.getconn();
        String sql = "delete from test_users where username = ?";
        try {
            pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, users.getUsername());
            int rs = pstmt.executeUpdate();
            if (rs > 0){
                bool = true;
                System.out.println("delete user successfully!");
            }

        }catch (SQLException e){
            e.printStackTrace();
        }finally {
            DbClose.addClose(pstmt, conn);
        }
        return bool;
    }