zoukankan      html  css  js  c++  java
  • FreeMarker调用JAVA静态方法

    官方文档地址:

    2009年的地址
    http://freemarker.sourceforge.net/docs/pgui_misc_beanwrapper.html#autoid_54

    https://freemarker.apache.org/docs/pgui_misc_beanwrapper.html#autoid_60   更新于2018-05-23

    Accessing static methods

    The TemplateHashModel returned from BeansWrapper.getStaticModels() can be used to create hash models for accessing static methods and fields of an arbitrary class.

    BeansWrapper wrapper = BeansWrapper.getDefaultInstance();
    TemplateHashModel staticModels = wrapper.getStaticModels();
    TemplateHashModel fileStatics =
        (TemplateHashModel) staticModels.get("java.io.File"); 

    And you will get a template hash model that exposes all static methods and static fields (both final and non-final) of the java.lang.System class as hash keys. Suppose that you put the previous model in your root model:

    root.put("File", fileStatics); 

    From now on, you can use ${File.SEPARATOR} to insert the file separator character into your template, or you can even list all roots of your file system by:

    <#list File.listRoots() as fileSystemRoot>...</#list> 

    Of course, you must be aware of the potential security issues this model brings.

    You can even give the template authors complete freedom over which classes' static methods they use by placing the static models hash into your template root model with

    root.put("statics", BeansWrapper.getDefaultInstance().getStaticModels()); 

    This object exposes just about any class' static methods if it's used as a hash with class name as the key. You can then use expression like ${statics["java.lang.System"].currentTimeMillis()} in your template. Note, however that this has even more security implications, as someone could even invoke System.exit() using this model if the method exposure level is weakened to EXPOSE_ALL.

    Note that in above examples, we always use the default BeansWrapper instance. This is a convenient static wrapper instance that you can use in most cases. You are also free to create your own BeansWrapper instances and use them instead especially when you want to modify some of its characteristics (like model caching, security level, or the null model representation).

  • 相关阅读:
    一些比较水的题目
    oracle not in,not exists,minus 数据量大的时候的性能问题
    简单的oracle分页语句
    oracle 查询结果集运算
    Spring注解详解
    HTTP报头Accept 和 Content-Type的区别
    vue 实现分转元的 过滤器
    oracle or语句的坑
    CSS样式 让你的输入的小写自动变成大写。
    js 十分精确身份证验证
  • 原文地址:https://www.cnblogs.com/skey_chen/p/1601620.html
Copyright © 2011-2022 走看看