BaseUtils.java

package com.tlcsdm.gen.base;

import com.alibaba.druid.util.StringUtils;
import lombok.Cleanup;

import jakarta.servlet.ServletOutputStream;
import jakarta.servlet.http.Cookie;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.InetAddress;
import java.net.URLEncoder;
import java.net.UnknownHostException;
import java.nio.charset.StandardCharsets;
import java.util.*;
import java.util.stream.Collectors;

/**
 * 常用方法封装
 *
 * @author: TangLiang
 * @date: 2021/4/14 15:16
 * @since: 1.0
 */
public class BaseUtils {

	/**
	 * 类不能实例化
	 */
	private BaseUtils() {
	}

	/**
	 * 不同浏览器将下载文件名处理为中文
	 * @param request HttpServletRequest对象
	 * @param s 文件名
	 * @return 文件名
	 * @throws UnsupportedEncodingException 不支持的解码方式
	 */
	public static String getFormatString(HttpServletRequest request, String s) throws UnsupportedEncodingException {
		String filename = s;
		String userAgent = request.getHeader("User-Agent").toUpperCase();
		if (userAgent.indexOf("FIREFOX") > 0) {
			filename = new String(s.getBytes(StandardCharsets.UTF_8), StandardCharsets.ISO_8859_1); // firefox浏览器
		}
		else if (userAgent.indexOf("MSIE") > 0) {
			filename = URLEncoder.encode(s, StandardCharsets.UTF_8);// IE浏览器
		}
		else if (userAgent.indexOf("CHROME") > 0) {
			filename = new String(s.getBytes(StandardCharsets.UTF_8), StandardCharsets.ISO_8859_1);// 谷歌
		}
		return filename;
	}

	/**
	 * 下载文件
	 * @param inputStream 文件输入流
	 * @param fileName 文件名
	 * @param request request
	 * @param response response
	 */
	public static void download(InputStream inputStream, String fileName, HttpServletRequest request,
			HttpServletResponse response) throws IOException {
		fileName = getFormatString(request, fileName);
		response.reset();
		response.setHeader("Content-Disposition", "attachment; filename=" + fileName);// 下载模式
		@Cleanup
		ServletOutputStream out = response.getOutputStream();
		byte[] content = new byte[65535];
		int length;
		while ((length = inputStream.read(content)) != -1) {
			out.write(content, 0, length);
			out.flush();
		}
	}

	/**
	 * 流转字节数组
	 * @param inputStream 流
	 * @return 流转字节数组
	 * @throws Exception IOException
	 */
	public static byte[] inputStreamToBytes(InputStream inputStream) throws IOException {
		ByteArrayOutputStream bas = new ByteArrayOutputStream();
		inputStream.transferTo(bas);
		return bas.toByteArray();
	}

	/**
	 * 流转字符串
	 * @param inputStream 流
	 * @return 流转字符串
	 * @throws Exception IOException
	 */
	public static String inputStreamToString(InputStream inputStream) throws IOException {
		ByteArrayOutputStream bas = new ByteArrayOutputStream();
		inputStream.transferTo(bas);
		return bas.toString();
	}

	/**
	 * 个位数填充0
	 * @param str 需要填充的字符串
	 * @return 填充后结果
	 */
	public static String fillWithZero(String str) {
		if (str != null && str.length() < 2) {
			return "0" + str;
		}
		return str;
	}

	/**
	 * 获得UUID
	 * @return UUID
	 */
	public static String getUuid() {
		return UUID.randomUUID().toString().replaceAll("-", "");
	}

	/**
	 * 返回成功信息(用于存储过程方式的结果返回)
	 * @param result 数据集
	 * @return java.util.Map
	 */
	public static Map<String, Object> success(Map<String, Object> result) {
		result.put("success", true);
		return result;
	}

	/**
	 * 返回成功信息(用于存储过程方式的结果返回)
	 * @param obj 数据集
	 * @return java.util.Map
	 */
	public static Map<String, Object> success(Object obj) {
		Map<String, Object> result = new HashMap<>(4);
		result.put("success", true);
		result.put("result", obj);
		return result;
	}

	/**
	 * 返回成功信息(用于存储过程方式的结果返回)
	 * @return java.util.Map
	 */
	public static Map<String, Object> success() {
		return Collections.singletonMap("success", true);
	}

	/**
	 * 返回失败信息(用于存储过程方式的结果返回)
	 * @param message 错误信息
	 * @return java.util.Map
	 */
	public static Map<String, Object> failed(String message) {
		Map<String, Object> result = new HashMap<>(4);
		result.put("success", false);
		result.put("message", message);
		return result;
	}

	/**
	 * 返回失败信息(用于存储过程方式的结果返回)
	 * @param result 数据集
	 * @param message 错误信息
	 * @return java.util.Map
	 */
	public static Map<String, Object> failed(Map<String, Object> result, String message) {
		result.put("success", false);
		result.put("message", message);
		return result;
	}

	/**
	 * 获取请求客户端ip地址
	 * @param request request
	 * @return 客户端ip地址
	 */
	public static String getIp(HttpServletRequest request) {
		String ip = request.getHeader("X-FORWARDED-FOR");
		if (StringUtils.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) {
			ip = request.getHeader("Proxy-Client-IP");
		}
		if (StringUtils.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) {
			ip = request.getHeader("WL-Proxy-Client-IP");
		}
		if (StringUtils.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) {
			ip = request.getHeader("HTTP_CLIENT_IP");
		}
		if (StringUtils.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) {
			ip = request.getHeader("HTTP_X_FORWARDED_FOR");
		}
		if (StringUtils.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) {
			ip = request.getRemoteAddr();
		}
		if ("0:0:0:0:0:0:0:1".equals(ip)) {
			return "127.0.0.1";
		}
		// 解决经过nginx转发, 配置了proxy_set_header x-forwarded-for
		// $proxy_add_x_forwarded_for;带来的多ip的情况
		if (ip != null && ip.length() > 15) {
			if (ip.indexOf(",") > 0) {
				ip = ip.substring(0, ip.indexOf(","));
			}
		}

		return ip;
	}

	/**
	 * 获取请求url路径
	 * @param request request
	 * @return url路径
	 */
	public static String getUrl(HttpServletRequest request) {
		String url = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()
				+ request.getServletPath();
		if (request.getQueryString() != null) {
			url += "?" + request.getQueryString();
		}
		return url;
	}

	/**
	 * 主机名
	 * @return 主机名
	 */
	public static String getHostName() {
		try {
			return InetAddress.getLocalHost().getHostName();
		}
		catch (UnknownHostException e) {
			e.printStackTrace();
		}
		return "未知";
	}

	/**
	 * 获取cookie值
	 * @param key cookie键
	 * @param request request
	 * @return cookie值
	 */
	public static String getCookieValue(String key, HttpServletRequest request) {
		Cookie[] cookies = request.getCookies();
		if (cookies != null) {
			for (Cookie cookie : cookies) {
				if (key.equals(cookie.getName())) {
					return cookie.getValue();
				}
			}
		}
		return "";
	}

	/**
	 * 分页
	 * @param list 需要分页的list
	 * @param page 当前页数
	 * @param limit 每次展示页数
	 * @return 分页后的list
	 */
	public static <T> List<T> page(List<T> list, Integer page, Integer limit) {
		return page != null && limit != null && page > 0 && limit > 0
				? list.stream().skip(limit * (page - 1)).limit(limit).collect(Collectors.toList()) : list;
	}

	/**
	 * 设置cookie
	 * @param response HttpServletResponse
	 * @param name cookie名字
	 * @param value cookie值
	 * @param maxAge cookie生命周期 以秒为单位
	 */
	public static void addCookie(HttpServletResponse response, String name, String value, int maxAge) {
		Cookie cookie = new Cookie(name, value);
		cookie.setPath("/");
		if (maxAge > 0) {
			cookie.setMaxAge(maxAge);
		}
		response.addCookie(cookie);
	}

	/**
	 * 首字母小写
	 */
	public static String toLowerCase4Index(String string) {
		if (Character.isLowerCase(string.charAt(0))) {
			return string;
		}

		char[] chars = string.toCharArray();
		chars[0] += 32;
		return String.valueOf(chars);
	}

	/**
	 * 首字母大写
	 */
	public static String toUpperCase4Index(String string) {
		char[] chars = string.toCharArray();
		chars[0] = toUpperCase(chars[0]);
		return String.valueOf(chars);
	}

	/**
	 * 字符转成大写
	 */
	public static char toUpperCase(char chars) {
		if (97 <= chars && chars <= 122) {
			chars ^= 32;
		}
		return chars;
	}

	/**
	 * 根据容量获取map初始大小 参考JDK8中putAll方法中的实现以及 guava的newHashMapWithExpectedSize方法
	 * @param expectedSize 容量大小
	 */
	public static int newHashMapWithExpectedSize(int expectedSize) {
		if (expectedSize < 3) {
			return 4;
		}
		else {
			return expectedSize < 1073741824 ? (int) ((float) expectedSize / 0.75F + 1.0F) : 2147483647;
		}
	}

	/**
	 * 深度克隆
	 */
	public static Object deepClone(Object object) {
		try {
			ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
			ObjectOutputStream objectOutputStream = new ObjectOutputStream(byteArrayOutputStream);
			if (object != null) {
				objectOutputStream.writeObject(object);
			}
			ObjectInputStream objectInputStream = new ObjectInputStream(
					new ByteArrayInputStream(byteArrayOutputStream.toByteArray()));
			return objectInputStream.readObject();
		}
		catch (Exception e) {
			return null;
		}
	}

	/**
	 * 深度克隆
	 */
	public static void callbackNotFound(HttpServletResponse response, Exception e) {
		e.printStackTrace();
		response.setContentType("text/html;charset=utf-8");
		@Cleanup
		PrintWriter out = null;
		try {
			out = response.getWriter();
			out.print("<span style=\"display:block;text-align: center;margin:0 auto;min-width: 150px;\">"
					+ e.getMessage() + "</span><br/>");
			out.print(
					"<br/><button autocomplete=\"off\" onclick=\"javascript:window.history.back(-1);return false;\" autofocus=\"true\"\n"
							+ "            style=\"display:block;margin:0 auto;min-width: 150px;background-color:rgb(0, 138, 203);color: rgb(255, 255, 255);\">\n"
							+ "        返回上一个页面\n" + "    </button>");
			out.flush();
		}
		catch (IOException ex) {
			ex.printStackTrace();
		}
	}

}