Personal-TODO - 《速记》

文章
Json序列化
Swagger
DateMath
- 工具类
并行流
日期
RestTemplate
finalize
FastJson

文章

fastjson => jackson

零拷贝

Json序列化

//User 类序列化成 { “userName”:”张三”}，又要将 { “name”:”张三”} 序列化成 User类。

//gson
class User{
@SerializedName(value="userName",alternate={"name"})
private String userName;
}
//fastjson
@JSONField(name  = "project")

1.fastjson List转JSONArray
List list = new ArrayList();
JSONArray array= JSONArray.parseArray(JSON.toJSONString(list))；

2.fastjson JSONArray转List
JSONArray array = new JSONArray();
List list = JSONObject.parseArray(array.toJSONString(), EventColAttr.class);

3.fastjson 字符串转List
String str = "";
List list = JSONObject.parseArray(str,T.class);

切面表达式：
https://cloud.tencent.com/developer/article/1497814

通过切面解决认证问题：
1.认证失效（账号被顶/过期）；捕获到认证失效异常后，调用认证逻辑，携带最新Token再次执行业务逻辑并返回；

iotAuthImpl.java
AuthInvalidAop.java

Swagger

Swagger自动转驼峰问题(Action ==> swagger ==> action)
不可取、待确认是否是该原因： mapStruct 貌似也是通过 get，set方法去识别;
1.通过FastJson的@JSONField注解解决/
2.仅返回对应的泛型类，实际可返回new JSONArray();

DateMath


import cn.hutool.core.date.LocalDateTimeUtil;
import cn.hutool.core.math.MathUtil;
import cn.hutool.core.util.NumberUtil;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.util.Locale;
public class test{ 
    public static void main(String[] args) {
        double v = DateTimeMathUtil.todayInMothPercent();
        System.out.println("v = " + v);
        double div = NumberUtil.div(20, 29, 4);
        System.out.println("div = " + div);
        //68.965515
        System.out.println((float) 20 / (float) 29 * 100);
        //68.96551724137932
        System.out.println((double) 20 / (double) 29 * 100);
        String time = LocalDateTimeUtil.format(LocalDateTime.now(ZoneId.of("Asia/Shanghai")), "yyyyMMddHHmmss");
        System.out.println(time.toUpperCase(Locale.ROOT));
        int dayOfMonth = LocalDateTimeUtil.now().getDayOfMonth();
        System.out.println("dayOfMonth = " + dayOfMonth);
        LocalDate date = LocalDate.of(2020, 2, 20);
        System.out.println("============");
        //第20天
        System.out.println(date.getDayOfMonth());
        //最多29天
        System.out.println(date.getMonth().maxLength());
        //至少28天
        System.out.println(date.getMonth().minLength());
        //当前月有29天
        System.out.println(date.getMonth().length(date.isLeapYear()));
//        DateTimeFormatter df = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
//        LocalDateTime parse = LocalDateTime.parse("2020-08-08 00:00:00",df);
//        int dayOfMonth1 = parse.getDayOfMonth();
//        int length = parse.getMonth().length(LocalDate.now().isLeapYear());
//        System.out.println("length = " + length);
//        System.out.println("dayOfMonth1 = " + dayOfMonth1);
//        System.out.println("time = " + time);
    }
}

工具类

package com.time.common.utils.date;
import cn.hutool.core.util.NumberUtil;
import java.time.LocalDate;
/**
 * @author yx.Jiang
 * @desc 日期/时间计算工具类
 * @date 2021-09-01 16:18
 */
public class DateTimeMathUtil {
    /**
     * 已过日期占比（Percentage of elapsed time）
     *
     * @return 默认保留四位小数【四舍五入】
     */
    public static double todayInMothPercent() {
        return dayInMothPercent(LocalDate.now(), 4);
    }
    /**
     * 已过日期占比（Percentage of elapsed time）
     *
     * @param scale 小数位
     * @return 默认保留四位小数【四舍五入】
     */
    public static double todayInMothPercent(int scale) {
        return dayInMothPercent(LocalDate.now(), scale);
    }
    /**
     * 已过日期占比（Percentage of elapsed time）
     *
     * @param localDate 日期
     * @return 默认保留四位小数【四舍五入】
     */
    public static double dayInMothPercent(LocalDate localDate) {
        return dayInMothPercent(localDate, 4);
    }
    /**
     * 已过日期占比（Percentage of elapsed time）
     *
     * @param localDateTime 日期
     * @param scale         小数位
     * @return 默认保留四位小数【四舍五入】
     */
    public static double dayInMothPercent(LocalDate localDateTime, int scale) {
        int today = localDateTime.getDayOfMonth();
        int maxDays = localDateTime.getMonth().maxLength();
        return NumberUtil.div(today, maxDays, scale);
    }
}

并行流

Arrays.stream(values())
👍 Stream.of(values()).parallel()

非并行流
1927
1238
1212
1173
1009

并行流
1755
947
975
1013
999
878

[2021-09-02 17:29:18.259 http-nio-8088-exec-10
[2021-09-02 17:29:18.261 http-nio-8088-exec-10
[2021-09-02 17:29:18.263 ForkJoinPool.commonPool-worker-1
[2021-09-02 17:29:18.264 ForkJoinPool.commonPool-worker-1
[2021-09-02 17:29:18.265 ForkJoinPool.commonPool-worker-1
[2021-09-02 17:29:18.265 ForkJoinPool.commonPool-worker-1
[2021-09-02 17:29:18.266 ForkJoinPool.commonPool-worker-0
[2021-09-02 17:29:18.266 ForkJoinPool.commonPool-worker-0
[2021-09-02 17:29:18.266 ForkJoinPool.commonPool-worker-0
[2021-09-02 17:29:18.265 http-nio-8088-exec-10
[2021-09-02 17:29:18.268 ForkJoinPool.commonPool-worker-3
[2021-09-02 17:29:18.268 ForkJoinPool.commonPool-worker-0
[2021-09-02 17:29:18.269 http-nio-8088-exec-10
[2021-09-02 17:29:18.271 http-nio-8088-exec-10
[2021-09-02 17:29:18.332 ForkJoinPool.commonPool-worker-0
[2021-09-02 17:29:18.332 ForkJoinPool.commonPool-worker-0
[2021-09-02 17:29:18.665 http-nio-8088-exec-10
[2021-09-02 17:29:18.666 http-nio-8088-exec-10
[2021-09-02 17:29:19.134 ForkJoinPool.commonPool-worker-1
[2021-09-02 17:29:19.136 ForkJoinPool.commonPool-worker-1
[2021-09-02 17:29:19.138 http-nio-8088-exec-10
[2021-09-02 17:29:19.139 http-nio-8088-exec-10

日期

计算当前日期的一周前：
LocalDate today = LocalDate.now();
LocalDate aWeekAgo= today.minus(1, ChronoUnit.WEEKS);

String format = LocalDate.now().format(DateTimeFormatter.ISO_LOCAL_DATE);
System.out.println(“format = “ + format);
输出：
format = 2021-09-02

RestTemplate

自动URLEncode


import cn.hutool.crypto.digest.DigestUtil;
import cn.hutool.crypto.digest.HMac;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Configuration;
import org.springframework.stereotype.Component;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.time.Instant;
import java.util.*;
import java.util.stream.Collectors;
import static cn.hutool.crypto.digest.HmacAlgorithm.HmacSHA1;
/**
 * @author yx.Jiang
 * @desc 天氣API
 * @date 2021-09-03 15:40
 */
@Configuration
public class WeatherSignUtil {
    /**
     * 新知天气公钥
     * https://docs.seniverse.com/api/start/key.html
     */
    private static String publicKey;
    @Value("${weather.publicKey}")
    public void setPublicKey(String publicKey) {
        WeatherSignUtil.publicKey = publicKey;
    }
    /**
     * 新知天气私钥
     * https://docs.seniverse.com/api/start/key.html
     */
    private static String privateKey;
    @Value("${weather.privateKey}")
    public void setPrivateKey(String privateKey) {
        WeatherSignUtil.privateKey = privateKey;
    }
    /**
     * 生成签名
     *
     * @return sign
     */
    public static String genSign() {
        HashMap<String, Object> map = new HashMap<>();
        //时间戳
        map.put("ts", Instant.now().getEpochSecond());
        //sign有效期
        map.put("ttl", 1_800);
        //公钥
        map.put("uid", publicKey);
        String rawStr = map.keySet()
                .stream()
                .sorted(String::compareTo)
                .map(key -> key + "=" + map.get(key))
                .collect(Collectors.joining("&", "", ""));
        String sign = genSign(rawStr);
        System.out.println("sign1 = " + sign);
        try {
            sign = URLEncoder.encode(sign, StandardCharsets.UTF_8.name());
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        System.out.println("sign2 = " + sign);
        return rawStr + "&sig=" + sign;
    }
    /**
     * 生成签名
     *
     * @param rawStr 原始串
     * @return sign
     */
    private static String genSign(String rawStr) {
        //HMAC-SHA1  ——   私钥加密
        HMac hmac = DigestUtil.hmac(HmacSHA1, privateKey.getBytes(StandardCharsets.UTF_8));
        return hmac.digestBase64(rawStr, Boolean.FALSE);
    }
}

restTemplate请求接口响应 403 异常；
org.springframework.web.client.HttpClientErrorException$Forbidden: 403 Forbidden
以为是生成的sign有问题，再三确认后（单独拿生成的sign自行拼接URL在浏览器请求无问题后）；

debug中的实际请求URL为（URLEncode后的结果）：
https://api.seniverse.com/v3/weather/hourly.json?ts%3D1630664408%26ttl%3D1800%26uid%3DPOOzALiQ_Pcb1qPPM%26sig%3DZw7gxWoLf629a0OIuCq16p5%252FF%252F4%253D&language%3Dzh-Hans%26location%3D%E4%B8%8A%E6%B5%B7%26unit%3Dc&start=0&hours=24

将其decode后
http://tool.chinaz.com/tools/urlencode.aspx

这是
结果如上图所示：
https://api.seniverse.com/v3/weather/hourly.json?ts=1630664408&ttl=1800&uid=POOzALiQ_Pcb1qPPM&sig=Zw7gxWoLf629a0OIuCq16p5%2FF%2F4%3D&language=zh-Hans&location=上海&unit=c&start=0&hours=24

j将解码后的URL输入浏览器，可正常返回结果:

接下来就是要：避免RestTemplate的UrlEncode，参考链接https://blog.csdn.net/wangooo/article/details/117161950

仅urlEncode请求中的特殊字符（如：汉字、sign(28bit—base64)）；

finalize

@Deprecated
class HashDemo {
    public static HashDemo save = null;
    public void isA() {
        System.out.println("111-isA");
    }
    @Override
    protected void finalize() throws Throwable {
        super.finalize();
        System.out.println("ddd-finalize");
        HashDemo.save = this;
    }
    public static void main(String[] args) throws InterruptedException {
        save = new HashDemo();
        save = null;
        System.gc();
        Thread.sleep(500);
        if (save != null) {
            save.isA();
        } else {
            System.out.println("222---111");
        }
        save = null;
        System.gc();
        Thread.sleep(500);
        if (save != null) {
            save.isA();
        } else {
            System.out.println("222---222");
        }
    }
}
//输出结果
ddd-finalize
111-isA
222---222

FastJson

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.annotation.JSONField;
import lombok.Data;
import java.time.LocalDate;
import java.time.LocalDateTime;
    public static void main(String[] args) {
        User user = new User();
        user.setName("测试序列化");
        user.setBirthday(LocalDateTime.now());
        user.setTime(LocalDateTime.now());
        user.setDate(LocalDate.now());
        String s = JSON.toJSONStringWithDateFormat(user, "yyyy-MM-dd HH:mm:ss");
        System.out.println(s);
        //{"birthday":"2021-09-24 19:31:23","date":"2021-09-24","name":"测试序列化","time":"19:31"}
    }
    @Data
    static class User {
        private String name;
        private LocalDateTime birthday;
        @JSONField(format = "HH:mm")
        private LocalDateTime time;
        private LocalDate date;
    }