List<list>进行去重排序

客官°小女子只卖身不卖艺 2024-04-17 06:24 16阅读 0赞

接到任务 进行一个菜单去重排序的功能 还是比较有意思的

背景：一个用户 存在 多个角色  一个角色分别有对应的菜单  所以要进行合并 去重 排序处理 并且菜单拥有二级甚至三级菜单

先定义一个Menu类  并且重写它的hashcode和equals

>     package com.sitech.smartcity.common.entity;
>     
>     import java.util.List;
>     
>     public class Menu {
>        private String menuName;
>        private String url;
>        private List<Menu> menus;
>        private String openType;//0:iframe嵌套  1： load加载 ；2 ：window.location打开新界面
>        private String logourl;
>        private String code;//app业务编码
>        private String classCode;//分类编码
>        private String appid;
>        private Integer classPriority;//排序字段
>     
>        public Integer getClassPriority() {
>           return classPriority;
>        }
>     
>        public void setClassPriority(Integer classPriority) {
>           this.classPriority = classPriority;
>        }
>     
>        public String getMenuName() {
>           return menuName;
>        }
>     
>        public void setMenuName(String menuName) {
>           this.menuName = menuName;
>        }
>     
>        public String getUrl() {
>           return url;
>        }
>     
>        public void setUrl(String url) {
>           this.url = url;
>        }
>     
>        public List<Menu> getMenus() {
>           return menus;
>        }
>     
>        public void setMenus(List<Menu> menus) {
>           this.menus = menus;
>        }
>     
>        public String getOpenType() {
>           return openType;
>        }
>     
>        public void setOpenType(String openType) {
>           this.openType = openType;
>        }
>     
>        public String getLogourl() {
>           return logourl;
>        }
>     
>        public void setLogourl(String logourl) {
>           this.logourl = logourl;
>        }
>     
>        public String getCode() {
>           return code;
>        }
>     
>        public void setCode(String code) {
>           this.code = code;
>        }
>     
>        public String getClassCode() {
>           return classCode;
>        }
>     
>        public void setClassCode(String classCode) {
>           this.classCode = classCode;
>        }
>     
>        public String getAppid() {
>           return appid;
>        }
>     
>        public void setAppid(String appid) {
>           this.appid = appid;
>        }
>     
>        @Override
>        public boolean equals(Object o) {
>           if (this == o) return true;
>           if (o == null || getClass() != o.getClass()) return false;
>           Menu menu = (Menu) o;
>           if (menuName != null ? !menuName.equals(menu.menuName) : menu.menuName != null) return false;
>           if (url != null ? !url.equals(menu.url) : menu.url != null) return false;
>           if (openType != null ? !openType.equals(menu.openType) : menu.openType != null) return false;
>           if (code != null ? !code.equals(menu.code) : menu.code != null) return false;
>           if (classCode != null ? !classCode.equals(menu.classCode) : menu.classCode != null) return false;
>           if (appid != null ? !appid.equals(menu.appid) : menu.appid != null) return false;
>           return classPriority != null ? classPriority.equals(menu.classPriority) : menu.classPriority == null;
>        }
>     
>        @Override
>        public int hashCode() {
>           int result = menuName != null ? menuName.hashCode() : 0;
>           result = 31 * result + (url != null ? url.hashCode() : 0);
>           result = 31 * result + (menus != null ? menus.hashCode() : 0);
>           result = 31 * result + (openType != null ? openType.hashCode() : 0);
>           result = 31 * result + (logourl != null ? logourl.hashCode() : 0);
>           result = 31 * result + (code != null ? code.hashCode() : 0);
>           result = 31 * result + (classCode != null ? classCode.hashCode() : 0);
>           result = 31 * result + (appid != null ? appid.hashCode() : 0);
>           result = 31 * result + (classPriority != null ? classPriority.hashCode() : 0);
>           return result;
>        }
>     }

然后 写几个 方法 用来合并 去重 排序的方法

>     //清除重复数据 利用set集合的 无重复特点 
>     public static List removeDuplicate(List list) {
>        HashSet h = new HashSet(list);
>        list.clear();
>        list.addAll(h);
>        return list;
>     }
>     
>     //根据排序字段进行排序
>     public static List compareList(List<Menu> list){
>        Collections.sort(list, new Comparator<Menu>() {
>           @Override
>           public int compare(Menu m1,Menu m2) {
>              if (m1.getClassPriority() > m2.getClassPriority()) {
>                 return 1;
>              }
>              if (m1.getClassPriority() == m2.getClassPriority()) {
>                 return 0;
>              }
>              return -1;
>           }
>        });
>        return list;
>     }
>     
>     
>     //递归  合并  去重
>     public static void trecursive(List<Menu> list){
>        try {
>           for(Iterator<Menu> oneIter = list.iterator(); oneIter.hasNext();){
>              Menu one = oneIter.next();
>     
>              for(Iterator<Menu> twoIter = list.iterator(); twoIter.hasNext();){
>                 Menu two = twoIter.next();
>                 //classcode为菜单的唯一标识  此处使用刚才重写的equals比较两个Menu对象也可
>                 if(one.getClassCode()!=null&&one.getClassCode().equals(two.getClassCode())){
>                    //如果进入 说明存在两个相同菜单  子菜单为空的情况  填充菜单  再去重
>                    if (one.getMenus() == null && two.getMenus() != null) {
>                       one.setMenus(two.getMenus());
>                    }
>                    if (two.getMenus() == null && one.getMenus() != null) {
>                       two.setMenus(one.getMenus());
>                    }
>                    if (two.getMenus() == null && one.getMenus() == null) {
>                       continue;
>                    }
>                    //否则合并  去重被合并菜单
>                    one.getMenus().addAll(two.getMenus());
>                    two.setMenus(one.getMenus());
>                    removeDuplicate(one.getMenus());
>                    compareList(one.getMenus());
>                    //递归
>                    trecursive(one.getMenus());
>                 }
>              }
>           }
>        }catch (Exception e){
>           e.printStackTrace();
>        }
>     }