Spring Web MVC

上传图片

1.方法参数
MultipartFile photo
2.根据servlet上下文获得存放图片的真实路径

                ServletContext context = req.getServletContext();
                String path = context.getRealPath("/images");

3.根据自定义工具类生产UUID格式的字符串图片文件名
String filename = CommonUtil.getRandomFileName(photo.getOriginalFilename());
4.根据photo的方法上传图片
photo.transferTo(new File(path + "/" + filename));

配置spring自带的编码过滤器

  <filter>
    <filter-name>characterEncodingFilter</filter-name>
    <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
    <init-param>
        <param-name>encoding</param-name>
        <param-value>utf-8</param-value>
    </init-param>
  </filter>
  
  <filter-mapping>
    <filter-name>characterEncodingFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>

CharacterEncodingFilter这个类有encoding的属性来设置编码格式

解决延迟加载和会话关闭的矛盾

方法一：配置OpenSessionInViewFilter过滤器延迟会话的生命周期

  <filter>
    <filter-name>osiv</filter-name>
    <filter-class>org.springframework.orm.hibernate5.support.OpenSessionInViewFilter</filter-class>
  </filter>
  
  <filter-mapping>
    <filter-name>osiv</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>

方法二：在业务层需要解决的方法里直接初始化数据

        if (!Hibernate.isInitialized(user)) {
            Hibernate.initialize(user);
        }