SMBMS项目-准备工作

• 2020 年 5 月 20 日
• 笔记
• 项目

项目搭建准备工作

1、基础准备工作

• 搭建一-个maven web项目
• 配置Tomcat
• 测试项目是否能够跑起来
• 导入项目中会遇到的jar包
  • jsp,Servlet,mysq|驱动, jstl, stand..

2、创建项目结构

3、编写实体类;

• ORM映射:表-类映射,pojo类

4、编写基础公共类

4.1数据库配置文件db.properties

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306?/smbms?useUnicode=true&characterEncoding=utf-8&serverTimeZone=GMT
user=root
password=123456

4.2编写数据库的公共类

public class BaseDao {
    private static String driver;
    private static String url;
    private static String username;
    private static String password;

    static{
        Properties properties=new Properties();
        //通过类加载器加载资源
        InputStream is = BaseDao.class.getClassLoader().getResourceAsStream("db.properties");
        try {
            properties.load(is);
        } catch (IOException e) {
            e.printStackTrace();
        }
        driver = properties.getProperty(driver);
        url = properties.getProperty(url);
        username = properties.getProperty(username);
        password = properties.getProperty(password);
    }

    //获取数据库的连接
    public static Connection getConnection(){
        Connection connection=null;
        try {
            Class.forName(driver);
            connection = DriverManager.getConnection(url, username, password);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return connection;
    }

    //编写查询公共类
    public static ResultSet execute(Connection connection,String sql,Object[] params,ResultSet resultSet,PreparedStatement preparedStatement) throws SQLException {
        preparedStatement = connection.prepareStatement(sql);
        for (int i = 0; i <params.length ; i++) {
            preparedStatement.setObject(i+1,params[i]);
        }
        resultSet = preparedStatement.executeQuery();
        return resultSet;
    }
    //编写增删改的公共方法
    public static int execute(Connection connection,String sql,Object[] params,PreparedStatement preparedStatement) throws SQLException {
        preparedStatement = connection.prepareStatement(sql);
        for (int i = 0; i <params.length ; i++) {
            preparedStatement.setObject(i+1,params[i]);
        }
        int updateRows = preparedStatement.executeUpdate();
        return updateRows;
    }

    //释放资源类
    public static boolean closeResource(Connection connection,PreparedStatement preparedStatement,ResultSet resultSet){
        boolean flag=true;
        if (resultSet!=null){
            try {
                resultSet.close();
                resultSet=null;
            } catch (SQLException throwables) {
                throwables.printStackTrace();
                flag=false;
            }
        }
        if (preparedStatement!=null){
            try {
                preparedStatement.close();
                preparedStatement=null;
            } catch (SQLException throwables) {
                throwables.printStackTrace();
                flag=false;
            }
        }
        if (connection!=null){
            try {
                connection.close();
                connection=null;
            } catch (SQLException throwables) {
                throwables.printStackTrace();
                flag=false;
            }
        }
        return false;
    }
}

4.3编写字符编码过滤器，并在web.xml中注册

public class CharacterEncodingFilter implements Filter {
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws IOException, ServletException {
        req.setCharacterEncoding("utf-8");
        resp.setCharacterEncoding("utf-8");
        chain.doFilter(req,resp);
    }

    public void destroy() {

    }
}

    <filter>
        <filter-name>CharacterEncodingFilter</filter-name>
        <filter-class>com.chao.filter.CharacterEncodingFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>CharacterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

5、导入静态资源

后续正在学习中。。。

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