前端工具 fns

 

1、首先需要引入一些xsd，以及页面配置

<?xml version="1.0" encoding="UTF-8" ?>

<taglib xmlns="http://java.sun.com/xml/ns/j2ee"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"
  version="2.0">
 
<function>
    <description>获取字典对象列表</description>
    <name>getDictList</name>
    <function-class>com.modules.sys.utils.DictUtils</function-class>
    <function-signature>java.util.List getDictList(java.lang.String)</function-signature>
    <example>${fns:getDictList(type)}</example>  
  </function>


</taglib>

2、编写后台工具类

package com.modules.sys.utils;
public class DictUtils {
    
    //通过bean类型获取到dao  工具类如下
    private static DictDao dictDao = BeanUtil.getBean(DictDao.class);

    public static List<Dict> getDictList(String type){
        Dict dict=new Dict();
        dict.setType(type);
        return dictDao.findAllList();
    }

}

手动获取到 bean，需要在spring的配置文件中进行注册

<bean id="beanUtil" class="com.modules.utils.BeanUtil" lazy-init="false"></bean>

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.util.Assert;


public class BeanUtil implements ApplicationContextAware {

    private static ApplicationContext applicationContext;

    /**
     * 实现ApplicationContextAware接口的context注入函数, 将其存入静态变量.
     */

    public void setApplicationContext(ApplicationContext applicationContext)
            throws BeansException {
        BeanUtil.applicationContext = applicationContext;
    }

    /**
     * 取得存储在静态变量中的ApplicationContext.
     */
    public static ApplicationContext getContext() {
        checkApplicationContext();
        return applicationContext;
    }

    /**
     * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
     */
    @SuppressWarnings("unchecked")
    public static <T> T getBean(String name) {
        checkApplicationContext();
        return (T) applicationContext.getBean(name);
    }

    /**
     * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
     */
    @SuppressWarnings("unchecked")
    public static <T> T getBean(Class<T> clazz) {
        checkApplicationContext();
        System.out.println(clazz);
        return (T) applicationContext.getBeansOfType(clazz);
    }

    /**
     * 清除applicationContext静态变量.
     */
    public static void cleanApplicationContext() {
        applicationContext = null;
    }

    private static void checkApplicationContext() {
        Assert.notNull(applicationContext,
                "applicationContext未注入,请在applicationContext.xml中定义BeanUtil");
    }
}

前端通过  ${fns:getDictList('nationality_flag')} 。直接获取list

可以结合缓存将一些不常改变的数据  缓存起来。既加快了查询速度。也方便了页面数据获取