JAVA总结工具类（一）

	/**
	 * 使用JwtToken
	 * 从cookie中获取用户ID方法
	 * @param request
	 * @param tenantId
	 * @return 
	 */
	private String getUserIdFromCookie(HttpServletRequest request, String tenantId) {
		String token = CookieUtils.getCookie(request, "v_authorization");
		if (token == null) {
			return null;
		}
		JwtToken jwtToken = null;
		try {
			jwtToken = Utils.decodeSignatureToken(token, this.cookieEncryptKey);
		} catch (Exception e) {
			return null;
		}
		long expire = jwtToken.getExpire().getTime();
		long now = DateUtils.getGMTTimeInMillis().longValue();
		if (now > expire) {
			return null;
		}
		Map<String, String> payload = jwtToken.getPayload();
		String uid = (String) payload.get("uid");
		if (!tenantId.equals(payload.get("tenantId"))) {
			return null;
		}
		if (!Utils.isAnonymityUser(uid)) {
			return null;
		}
		return uid;
	}

	/**
	 * 获取用户真实IP方法
	 * @param request
	 * @return
	 */
	public String getIpAddress(HttpServletRequest request) {
		String ip = request.getHeader("x-forwarded-for");
		if ((ip == null) || (ip.length() == 0) || ("unknown".equalsIgnoreCase(ip))) {
			ip = request.getHeader("Proxy-Client-IP");
		}
		if ((ip == null) || (ip.length() == 0) || ("unknown".equalsIgnoreCase(ip))) {
			ip = request.getHeader("WL-Proxy-Client-IP");
		}
		if ((ip == null) || (ip.length() == 0) || ("unknown".equalsIgnoreCase(ip))) {
			ip = request.getHeader("HTTP_CLIENT_IP");
		}
		if ((ip == null) || (ip.length() == 0) || ("unknown".equalsIgnoreCase(ip))) {
			ip = request.getHeader("HTTP_X_FORWARDED_FOR");
		}
		if ((ip == null) || (ip.length() == 0) || ("unknown".equalsIgnoreCase(ip))) {
			ip = request.getRemoteAddr();
		}
		return ip;
	}

Optional方法

import java.util.Optional;

public class OptionalTest {

     public static void main(String[] args) throws Throwable {

         //创建一个你好的String类型Optional
         Optional ofOptional=Optional.of("你好");
         //如果我们用of方法创建Optional对象时，所窜入的值null 则抛出NullPointerExeption
         Optional unllOfPtional = Optional.of(null);
         //指定的值创建Optional对象 ；不管传入的值是否为null不为空 创建的时候都不会报错
         Optional ofNullOptional = Optional.ofNullable(null);
         Optional NullOptionalof = Optional.ofNullable("list");
         //创建一个空的String类型的Optional对象
         Optional empty = Optional.empty();
         //如果创建的Optional对象中存在值就返回值 如果没有值存在 则抛出NoSuchElementException异常
         System.out.println(ofOptional.get());//获取值
         System.err.println(empty.get());//报错
         //如果创建Optional中有值存在，则返回此值，否则返回一个默认的值
         System.out.println(ofOptional.orElse("nihao02"));
         System.out.println(empty.orElse("nihao01"));
         //如果创建Optional中有值存在，则返回此值，否则返回一个有Supplier接口生成的值
         System.out.println(ofOptional.orElseGet(()->"nihao03"));
         System.out.println(empty.orElseGet(()->"nihao04"));
         //
         System.out.println(ofOptional.orElseThrow(CustomException::new));
         System.out.println(empty.orElseThrow(CustomException::new));


         //map方法执行传入的lambda表达式参数对Optional实例的值进行修改,修改后的返回值仍然是一个Optional对象
         Optional<String> stringOptional = Optional.of("zhangsan");
         System.out.println(stringOptional.map(e -> e.toUpperCase()).orElse("失败"));

         stringOptional = Optional.empty();
         System.out.println(stringOptional.map(e -> e.toUpperCase()).orElse("失败"));

     }


}