解释以下代码 let res = [] while(nameList.length!==0){ let list = nameList.shift() let arr = [list] for (let i = 0; i < nameList.length; i++) { if (nameList[i].age === list.age) { arr = arr.concat(nameList.splice(i, 1)) i-- } } res.push(arr) }

这段代码是一个将相同年龄的人分组的算法，具体解释如下：

首先定义了一个空数组 `res`，用来存放分组结果。

进入while循环，循环终止条件是 `nameList` 数组为空。在每一次循环中，通过 `nameList.shift()` 取出 `nameList` 数组的第一个元素，并将其存入 `list` 中。

然后定义一个新数组 `arr`，将 `list` 存入其中。

进入for循环，循环遍历剩余的 `nameList` 数组中的元素，如果这些元素的年龄与 `list` 的年龄相同，则将其从 `nameList` 中移除，并将其存入 `arr` 数组中。

其中，删除元素时需要注意，因为在循环中删除元素会改变数组长度，因此需要在删除元素后将 `i` 值减一，以保证不会漏掉某些元素。

最后将 `arr` 存入 `res` 数组中，代表一个分组结束，继续进行下一个分组的计算，直到 `nameList` 数组为空时，退出循环，得到最终的分组结果。

总的来说，这段代码实现了一个将相同年龄的人分组的算法，可以在处理一些具有年龄相同或类似属性的数据时使用。

相关问题

使用中文解释ssm管理系统文件中util文件里PageHelper类解释以下代码package com.util; import java.util.ArrayList; import java.util.List; import javax.servlet.http.HttpServletRequest; public class PageHelper { public static void getPage(List<?> list, String name, List<String> nameList, List<String> valueList, int pageSize, String number, HttpServletRequest request, String method) { StringBuffer buffer = new StringBuffer(); String name2 = name.substring(0, 1).toUpperCase() + name.substring(1); String path = ""; String action = "getAll" + name2 + ".action"; if (method != null) { action = "query" + name2 + "ByCond.action"; } List<Object> objList = new ArrayList<Object>(); if (nameList != null && valueList != null) { for (int i = 0; i < nameList.size(); i++) { path += "&" + nameList.get(i) + "=" + valueList.get(i); } } int pageNumber = list.size(); int maxPage = pageNumber; if (maxPage % pageSize == 0) { maxPage = maxPage / pageSize; } else { maxPage = maxPage / pageSize + 1; } if (number == null) { number = "0"; } int start = Integer.parseInt(number) * pageSize; int over = (Integer.parseInt(number) + 1) * pageSize; int count = pageNumber - over; if (count <= 0) { over = pageNumber; } for (int i = start; i < over; i++) { Object obj = list.get(i); objList.add(obj); } buffer.append(" 共为"); buffer.append(maxPage); buffer.append("页 共有"); buffer.append(pageNumber); buffer.append("条 当前为第"); buffer.append((Integer.parseInt(number) + 1)); buffer.append("页 "); if ((Integer.parseInt(number) + 1) == 1) { buffer.append("首页"); } else { buffer.append("<a href="" + name + "/" + action + "?number=0" + path + "">首页</a>"); } buffer.append(" "); if ((Integer.parseInt(number) + 1) == 1) { buffer.append("上一页"); } else { buffer.append("<a href="" + name + "/" + action + "?number=" + (Integer.parseInt(number) - 1) + "" + path + "">上一页</a>"); } buffer.append(" "); if (maxPage <= (Integer.parseInt(number) + 1)) { buffer.append("下一页"); } else { buffer.append("<a href="" + name + "/" + action + "?number=" + (Integer.parseInt(number) + 1) + "" + path + "">下一页</a>"); } buffer.append(" "); if (maxPage <= (Integer.parseInt(number) + 1)) { buffer.append("尾页"); } else { buffer.append("<a href="" + name + "/" + action + "?number=" + (maxPage - 1) + "" + path + "">尾页</a>"); } String html = buffer.toString(); request.setAttribute("html", html); request.setAttribute(name + "List", objList); }

该代码是一个用于分页的工具类，主要包含一个静态方法getPage。该方法有以下参数：

- list: 需要分页的数据列表
- name: 数据对应的实体类名称
- nameList: 分页链接的参数名列表
- valueList: 分页链接的参数值列表
- pageSize: 每页显示的数据数量
- number: 当前页码
- request: HTTP请求对象
- method: 查询方法名

该方法的作用是根据传入的参数，生成分页链接，并将生成的链接添加到HTTP请求对象中。在生成分页链接时，会根据传入的参数生成对应的查询字符串，并将其添加到链接中。其中，name2是将实体类名称的首字母大写后的结果。path是请求路径，action是请求的动作。如果传入了method参数，则动作为"query"+name2+"ByCond.action"，否则动作为"getAll"+name2+".action"。objList是一个空的对象列表，暂时没有被使用。

ssm管理系统文件中util文件里PageHelper类解释以下代码package com.util; import java.util.ArrayList; import java.util.List; import javax.servlet.http.HttpServletRequest; public class PageHelper { public static void getPage(List<?> list, String name, List<String> nameList, List<String> valueList, int pageSize, String number, HttpServletRequest request, String method) { StringBuffer buffer = new StringBuffer(); String name2 = name.substring(0, 1).toUpperCase() + name.substring(1); String path = ""; String action = "getAll" + name2 + ".action"; if (method != null) { action = "query" + name2 + "ByCond.action"; } List<Object> objList = new ArrayList<Object>(); if (nameList != null && valueList != null) { for (int i = 0; i < nameList.size(); i++) { path += "&" + nameList.get(i) + "=" + valueList.get(i); } } int pageNumber = list.size(); int maxPage = pageNumber; if (maxPage % pageSize == 0) { maxPage = maxPage / pageSize; } else { maxPage = maxPage / pageSize + 1; } if (number == null) { number = "0"; } int start = Integer.parseInt(number) * pageSize; int over = (Integer.parseInt(number) + 1) * pageSize; int count = pageNumber - over; if (count <= 0) { over = pageNumber; } for (int i = start; i < over; i++) { Object obj = list.get(i); objList.add(obj); } buffer.append("&nbsp;&nbsp;共为"); buffer.append(maxPage); buffer.append("页&nbsp; 共有"); buffer.append(pageNumber); buffer.append("条&nbsp; 当前为第"); buffer.append((Integer.parseInt(number) + 1)); buffer.append("页 &nbsp;"); if ((Integer.parseInt(number) + 1) == 1) { buffer.append("首页"); } else { buffer.append("<a href=\"" + name + "/" + action + "?number=0" + path + "\">首页</a>"); } buffer.append("&nbsp;&nbsp;"); if ((Integer.parseInt(number) + 1) == 1) { buffer.append("上一页"); } else { buffer.append("<a href=\"" + name + "/" + action + "?number=" + (Integer.parseInt(number) - 1) + "" + path + "\">上一页</a>"); } buffer.append("&nbsp;&nbsp;"); if (maxPage <= (Integer.parseInt(number) + 1)) { buffer.append("下一页"); } else { buffer.append("<a href=\"" + name + "/" + action + "?number=" + (Integer.parseInt(number) + 1) + "" + path + "\">下一页</a>"); } buffer.append("&nbsp;&nbsp;"); if (maxPage <= (Integer.parseInt(number) + 1)) { buffer.append("尾页"); } else { buffer.append("<a href=\"" + name + "/" + action + "?number=" + (maxPage - 1) + "" + path + "\">尾页</a>"); } String html = buffer.toString(); request.setAttribute("html", html); request.setAttribute(name + "List", objList); }

The `PageHelper` class in the `util` package of the SSM management system is used to implement pagination functionality for displaying data in pages.

The `getPage` method takes the following parameters:

- `list`: the list of objects to be paginated
- `name`: the name of the entity being paginated
- `nameList`: a list of parameter names used for filtering the data
- `valueList`: a list of parameter values used for filtering the data
- `pageSize`: the number of objects to be displayed per page
- `number`: the current page number
- `request`: the HTTP servlet request object
- `method`: the name of the method used for filtering the data

The method first constructs the URL for the pagination links by appending the `action` parameter to the entity name. If a filter method is provided, it replaces the default `getAll` method with the filter method.

Next, it creates a new list to hold the paginated data and calculates the total number of pages based on the size of the original data list and the page size. It then adds the relevant parameters to the URL for each page and constructs the HTML code for the pagination links.

Finally, it sets the paginated data list and pagination HTML code as attributes of the request object to be passed back to the view for display.