前言
本文是博主從事后端開發以來，對公司、個人專案的經驗總結，包含代碼撰寫、功能推薦、第三方庫使用及優雅配置等，希望大家看到都能有所識訓
- 博主github地址: https://github.com/wayn111
一. 優雅的進行執行緒池例外處理
在Java開發中，執行緒池的使用必不可少，使用無回傳值 execute() 方法時，執行緒執行發生例外的話，需要記錄日志，方便回溯，一般做法是在執行緒執行方法內 try/catch 處理，如下：
@Test
public void test() throws Exception {
ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(5, 10, 60,
TimeUnit.SECONDS, new ArrayBlockingQueue<>(100000));
Future<Integer> submit = threadPoolExecutor.execute(() -> {
try {
int i = 1 / 0;
return i;
} catch (Exception e) {
log.error(e.getMessage(), e);
return null;
}
});
}
但是當執行緒池呼叫方法很多時，那么每個執行緒執行方法內都要 try/catch 處理，這就不優雅了，其實ThreadPoolExecutor類還支持傳入 ThreadFactory 引數，自定義執行緒工廠，在創建 thread 時，指定 setUncaughtExceptionHandler 例外處理方法，這樣就可以做到全域處理例外了，代碼如下：
ThreadFactory threadFactory = r -> {
Thread thread = new Thread(r);
thread.setUncaughtExceptionHandler((t, e) -> {
// 記錄執行緒例外
log.error(e.getMessage(), e);
});
return thread;
};
ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(5, 10, 60,
TimeUnit.SECONDS, new ArrayBlockingQueue<>(100000),
threadFactory);
threadPoolExecutor.execute(() -> {
log.info("---------------------");
int i = 1 / 0;
});
二. 執行緒池決絕策略設定錯誤導致業務介面執行超時
先介紹下執行緒池得四種決絕策略
- AbortPolicy：丟棄任務并拋出RejectedExecutionException例外，這是執行緒池默認的拒絕策略
- DiscardPolicy：丟棄任務，但是不拋出例外，如果執行緒佇列已滿，則后續提交的任務都會被丟棄，且是靜默丟棄，
使用此策略，可能會使我們無法發現系統的例外狀態，建議是一些無關緊要的業務采用此策略 - DiscardOldestPolicy：丟棄佇列最前面的任務，然后重新提交被拒絕的任務，此拒絕策略，是一種喜新厭舊的拒絕策略，是否要采用此種拒絕策略，還得根據實際業務是否允許丟棄老任務來認真衡量，
- CallerRunsPolicy：由呼叫執行緒處理該任務
如下是一個線上業務介面使用得執行緒池配置，決絕策略采用 CallerRunsPolicy
// 某個線上執行緒池配置如下
ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(
50, // 最小核心執行緒數
50, // 最大執行緒數，當佇列滿時，能創建的最大執行緒數
60L, TimeUnit.SECONDS, // 空閑執行緒超過核心執行緒時，回收該執行緒的最大等待時間
new LinkedBlockingQueue<>(5000), // 阻塞佇列大小,當核心執行緒使用滿時，新的執行緒會放進佇列
new CustomizableThreadFactory("task"), // 自定義執行緒名
new ThreadPoolExecutor.CallerRunsPolicy() // 執行緒執行的拒絕策略
);
在某些情況下，子執行緒任務呼叫第三方介面超時，導致核心執行緒數、最大執行緒數占滿、阻塞佇列占滿的情況下執行拒絕策略時，由于使用 CallerRunsPolicy 策略，導致業務執行緒執行子任務時繼續超時，進而導致介面執行例外，這種情況下，考慮到子執行緒任務得重要性，不是很重要得話，可以使用 DiscardPolicy 策略，要是很重要，可以發送到訊息佇列中持久化子執行緒任務資料待后續處理
三. 優雅的單例模式懶加載幫助類代碼實作
博主推薦通過靜態內部類實作單例模式，并實作懶加載效果，代碼如下
// 使用靜態內部類完成單例模式封裝，避免執行緒安全問題，避免重復初始化成員屬性
@Slf4j
public class FilterIpUtil {
private FilterIpUtil() {
}
private List<String> strings = new ArrayList<>();
// 代碼塊在FilterIpUtil實體初始化時才會執行
{
// 在代碼塊中完成檔案的第一次讀寫操作，后續不再讀這個檔案
System.out.println("FilterIpUtil init");
try (InputStream resourceAsStream = FilterIpUtil.class.getClassLoader().getResourceAsStream("filterIp.txt")) {
// 將檔案內容放到string集合中
IoUtil.readUtf8Lines(resourceAsStream, strings);
} catch (IOException e) {
log.error(e.getMessage(), e);
}
}
public static FilterIpUtil getInstance() {
return InnerClassInstance.instance;
}
// 使用內部類完成單例模式，由jvm保證執行緒安全
private static class InnerClassInstance {
private static final FilterIpUtil instance = new FilterIpUtil();
}
// 判斷集合中是否包含目標引數
public boolean isFilter(String arg) {
return strings.contains(arg);
}
}
四. 使用ip2region實作請求地址決議
在博主之前公司得專案中，ip決議是呼叫淘寶IP還有聚合IP介面獲取結果，通常耗時200毫秒左右，并且介面不穩定時而會掛，都會影響業務介面耗時，后來在 github 上了解到 ip2region 這個專案，使用本地ip庫查詢，查詢速度微秒級別， 精準度能達到90%，但是ip庫還是有少部分ip資訊不準，建議資料庫中把請求ip地址保存下來，簡介如下：
ip2region v2.0 - 是一個離線IP地址定位庫和IP定位資料管理框架，10微秒級別的查詢效率，提供了眾多主流編程語言的 xdb 資料生成和查詢客戶端實作基于 xdb 檔案的查詢，下面是一個 Spring 專案中 ip2region 幫助類來實作ip地址決議
/**
* ip2region工具類
*/
@Slf4j
@Component
public class Ip2region {
private Searcher searcher = null;
@Value("${ip2region.path:}")
private String ip2regionPath = "";
@PostConstruct
private void init() {
// 1、從 dbPath 加載整個 xdb 到記憶體，
String dbPath = ip2regionPath;
// 1、從 dbPath 加載整個 xdb 到記憶體，
byte[] cBuff;
try {
cBuff = Searcher.loadContentFromFile(dbPath);
searcher = Searcher.newWithBuffer(cBuff);
} catch (Exception e) {
log.error("failed to create content cached searcher: {}", e.getMessage(), e);
}
}
public IpInfoBean getIpInfo(String ip) {
if (StringUtils.isBlank(ip)) {
return null;
}
// 3、查詢
try {
long sTime = System.nanoTime();
// 國家|區域|省份|城市|ISP
String region = searcher.search(ip);
long cost = TimeUnit.NANOSECONDS.toMicros((long) (System.nanoTime() - sTime));
log.info("{region: {}, ioCount: {}, took: {} μs}", region, searcher.getIOCount(), cost);
if (StringUtils.isNotBlank(region)) {
String[] split = region.split("\|");
IpInfoBean ipInfo = new IpInfoBean();
ipInfo.setIp(ip);
if (!"".equals(split[0])) {
ipInfo.setCountry(split[0]);
}
if (!"".equals(split[2])) {
ipInfo.setProvince(split[2]);
}
if (!"".equals(split[3])) {
ipInfo.setCity(split[3]);
}
if (!"".equals(split[4])) {
ipInfo.setIsp(split[4]);
}
return ipInfo;
}
} catch (Exception e) {
log.error("failed to search({}): {}", ip, e);
return null;
}
// 4、關閉資源 - 該 searcher 物件可以安全用于并發，等整個服務關閉的時候再關閉 searcher
// searcher.close();
// 備注：并發使用，用整個 xdb 資料快取創建的查詢物件可以安全的用于并發，也就是你可以把這個 searcher 物件做成全域物件去跨執行緒訪問，
return null;
}
}
要注意得就是 ip2region v2.0 版本使用的xdb檔案不建議放在專案 resources 下一起打包，存在編碼格式問題，建議通過指定路徑加載得方式單獨放在服務器目錄下
五. 優雅得Springboot + mybatis配置多資料源方式
Springboot + mybatis 得專案中一般通過 @MapperScan 注解配置 dao 層包目錄，來實作 dao 層增強，其實專案中配置一個@MapperScan 是指定一個資料源，配置兩個@MapperScan就可以指定兩個資料源，通過不同得 dao 層包目錄區分，來實作不同資料源得訪問隔離，
比如下面代碼中，com.xxx.dao.master 目錄下為主資料源 dao 檔案，com.xxx.dao.slave 為從資料源 dao 檔案，這個方式比網上得基于 aop 加注解得方式更加簡潔好用，也沒有單個方法中使用不同資料源切換得問題，因此推薦這種寫法
/**
* 主資料源
*/
@Slf4j
@Configuration
@MapperScan(basePackages = {"com.xxx.dao.master"},
sqlSessionFactoryRef = "MasterSqlSessionFactory")
public class MasterDataSourceConfig {
@Bean(name = "MasterDataSource")
@Qualifier("MasterDataSource")
@ConfigurationProperties(prefix = "spring.datasource.master")
public DataSource clickHouseDataSource() {
return DruidDataSourceBuilder.create().build();
}
@Bean(name = "MasterSqlSessionFactory")
public SqlSessionFactory getSqlSessionFactory(@Qualifier("MasterDataSource") DataSource dataSource) throws Exception {
MybatisSqlSessionFactoryBean sessionFactoryBean = new MybatisSqlSessionFactoryBean();
sessionFactoryBean.setDataSource(dataSource);
sessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver()
.getResources("classpath*:mapper/master/*.xml"));
log.info("------------------------------------------MasterDataSource 配置成功");
return sessionFactoryBean.getObject();
}
}
/**
* 從資料源
*/
@Slf4j
@Configuration
@MapperScan(basePackages = {"com.xxx.dao.slave"},
sqlSessionFactoryRef = "SlaveSqlSessionFactory")
public class MasterDataSourceConfig {
@Bean(name = "SlaveDataSource")
@Qualifier("SlaveDataSource")
@ConfigurationProperties(prefix = "spring.datasource.slave")
public DataSource clickHouseDataSource() {
return DruidDataSourceBuilder.create().build();
}
@Bean(name = "SlaveSqlSessionFactory")
public SqlSessionFactory getSqlSessionFactory(@Qualifier("SlaveDataSource") DataSource dataSource) throws Exception {
MybatisSqlSessionFactoryBean sessionFactoryBean = new MybatisSqlSessionFactoryBean();
sessionFactoryBean.setDataSource(dataSource);
sessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver()
.getResources("classpath*:mapper/slave/*.xml"));
log.info("------------------------------------------SlaveDataSource 配置成功");
return sessionFactoryBean.getObject();
}
}
資料源yml配置
spring:
datasource:
type: com.alibaba.druid.pool.DruidDataSource
driverClassName: com.mysql.cj.jdbc.Driver
# 主庫資料源
master:
url: jdbc:mysql://localhost:3306/db1?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=true&serverTimezone=GMT%2B8
username: root
password:
slave:
url: jdbc:mysql://localhost:3306/db2?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=true&serverTimezone=GMT%2B8
username: root
password:
博主剛開始編碼一、兩年得時候一個專案中遇到了多資料源使用得問題，那時候題主便在網上搜索Spring 多資料源得帖子，大多數都是基于Spring提供得AbstractRoutingDataSource + AOP + 注解 來做動態切換，包括現在流行得 Mybatis plus 官方得多資料源解決方案也是這種做法，這種做法解決了博主當時得多資料源使用問題，后來加了一個需求，在一個定時任務中，查詢兩個資料源得資料，才發現動態切換在單個方法中不好用了，最后使用得原生jdbc資料源解決，多年后，博主在另一家公司得專案中又遇到了多資料源問題，但是這次博主在網上搜索得是Mybatis 多資料源，才發現了這個優雅得解決方案，進而推薦給大家
六. Spring Security專案中，使用MDC實作介面請求呼叫追蹤，以及用戶ID記錄
MDC介紹
MDC(Mapped Diagnostic Context，映射除錯背景關系)是 log4j 、logback及log4j2 提供的一種方便在多執行緒條件下記錄日志的功能，MDC 可以看成是一個與當前執行緒系結的哈希表，可以往其中添加鍵值對，MDC 中包含的內容可以被同一執行緒中執行的代碼所訪問，當前執行緒的子執行緒會繼承其父執行緒中的 MDC 的內容，當需要記錄日志時，只需要從 MDC 中獲取所需的資訊即可，
雖然MDC能夠方便得實作介面請求呼叫追蹤功能，但是它在子執行緒中會丟失父執行緒中添加得鍵值對資訊，解決方法是通過父執行緒中呼叫執行緒池前呼叫 MDC.getCopyOfContextMap() ，然后在子執行緒中第一個呼叫 MDC.setConextMap() 獲取鍵值對資訊，完整實作代碼如下：
/**
* 自定義Spring執行緒池，解決子執行緒丟失reqest_id問題
*/
public class ThreadPoolExecutorMdcWrapper extends ThreadPoolTaskExecutor {
@Override
public void execute(Runnable task) {
super.execute(ThreadMdcUtil.wrap(task, MDC.getCopyOfContextMap()));
}
@Override
public <T> Future<T> submit(Callable<T> task) {
return super.submit(ThreadMdcUtil.wrap(task, MDC.getCopyOfContextMap()));
}
@Override
public Future<?> submit(Runnable task) {
return super.submit(ThreadMdcUtil.wrap(task, MDC.getCopyOfContextMap()));
}
}
/**
* MDC幫助類，添加reqest_id
*/
public class ThreadMdcUtil {
public static final String REQUEST_ID = "request_id";
/**
* 設定請求唯一ID
*/
public static void setTraceIdIfAbsent() {
if (MDC.get(REQUEST_ID) == null) {
MDC.put(REQUEST_ID, IdUtil.getUid());
}
}
/**
* 存在userId則添加到REQUEST_ID中
* @param userId
*/
public static void setUserId(String userId) {
String s = MDC.get(REQUEST_ID);
if (s != null) {
MDC.put(REQUEST_ID, s + "_" + userId);
}
}
public static void removeTraceId() {
MDC.remove(REQUEST_ID);
}
public static <T> Callable<T> wrap(final Callable<T> callable, final Map<String, String> context) {
return () -> {
if (context == null) {
MDC.clear();
} else {
MDC.setContextMap(context);
}
setTraceIdIfAbsent();
try {
return callable.call();
} finally {
MDC.clear();
}
};
}
public static Runnable wrap(final Runnable runnable, final Map<String, String> context) {
return () -> {
if (context == null) {
MDC.clear();
} else {
MDC.setContextMap(context);
}
// 設定traceId
setTraceIdIfAbsent();
try {
runnable.run();
} finally {
MDC.clear();
}
};
}
}
在 Spring Security 中添加 token 過濾器
/**
* token過濾器 驗證token有效性
*
* @author ruoyi
*/
@Slf4j
@Component
public class JwtAuthenticationTokenFilter extends OncePerRequestFilter {
@Autowired
private TokenService tokenService;
@Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
throws ServletException, IOException {
try {
// 入口傳入請求ID
ThreadMdcUtil.setTraceIdIfAbsent();
LoginUserDetail loginUser = tokenService.getLoginUser(request);
if (Objects.nonNull(loginUser) && Objects.isNull(SecurityContextHolder.getContext().getAuthentication())) {
// 記錄userId
ThreadMdcUtil.setUserId(String.valueOf(loginUser.getMember().getId()));
tokenService.verifyToken(loginUser);
UsernamePasswordAuthenticationToken authenticationToken = new UsernamePasswordAuthenticationToken(loginUser, null, loginUser.getAuthorities());
authenticationToken.setDetails(new WebAuthenticationDetailsSource().buildDetails(request));
SecurityContextHolder.getContext().setAuthentication(authenticationToken);
}
chain.doFilter(request, response);
} finally {
// 出口移除請求ID
ThreadMdcUtil.removeTraceId();
}
}
}
最后在 logback.xml 中添加 %X{request_id}
<property name="pattern"
value="https://www.cnblogs.com/wayn111/archive/2022/11/30/%d{yyyy-MM-dd HH:mm:ss.SSS} [%X{request_id}] [%thread] [%-5level] %logger{36}:%L %M - %msg%n"/>
日志列印效果如下：
2022-11-27 21:29:48.008 [86c76336100c414dbe9217aeb099ccd5_12] [http-nio-82-exec-2] [INFO ] c.w.m.a.s.impl.IHomeServiceImpl:56 getHomeIndexDataCompletableFuture - getHomeIndexDataCompletableFuture:com.wayn.common.util.R@701f7b8e[code=200,msg=操作成功,map={bannerList=[{"createTime":"2020-06-26 19:56:03","delFlag":false,"id":14,"imgUrl":"https://m.360buyimg.com/mobilecms/s700x280_jfs/t1/117335/39/13837/263099/5f291a83E8ba761d0/5c0460445cb28248.jpg!cr_1125x449_0_166!q70.jpg.dpg","jumpUrl":"http://82.157.141.70/mall/#/detail/1155015","sort":0,"status":0,"title":"hh2","updateTime":"2022-06-19 09:16:46"},{"createTime":"2020-06-26 19:56:03","delFlag":false,"id":15,"imgUrl":"https://m.360buyimg.com/mobilecms/s700x280_jfs/t1/202096/26/11652/265782/616acb67E4fcdc9ac/8d7cdfbb6c934e67.jpg!cr_1125x449_0_166!q70.jpg.dpg","jumpUrl":"#/detail/1155015","sort":0,"status":0,"title":"hh","updateTime":"2022-06-19 09:04:58"}], newGoodsList=[{"actualSales":0,"brandId":0,"brief":"酥脆奶香，甜酸回味","categoryId":1008015,"counterPrice":56.00,"createTime":"2018-02-01 00:00:00","delFlag":false,"goodsSn":"1116011","id":1116011,"isHot":true,"isNew":true,"isOnSale":true,"keywords":"","name":"蔓越莓曲奇 200克","picUrl":"http://yanxuan.nosdn.127.net/767b370d07f3973500db54900bcbd2a7.png","retailPrice":36.00,"shareUrl":"","sort":5,"unit":"件","updateTime":"2018-02-01 00:00:00","virtualSales":10},{"actualSales":0,"brandId":0,"brief":"粉彩色澤，記錄生活","categoryId":1012003,"counterPrice":49.00,"createTime":"2018-02-01 00:00:00","delFlag":false,"goodsSn":"1127047","id":1127047,"isHot":false,"isNew":true,"isOnSale":true,"keywords":"","name":"趣味粉彩系列筆記本","picUrl":"http://yanxuan.nosdn.127.net/6c03ca93d8fe404faa266ea86f3f1e43.png","retailPrice":29.00,"shareUrl":"","sort":2,"unit":"件","updateTime":"2018-02-01 00:00:00","virtualSales":10},{"actualSales":0,"brandId":0,"brief":"慢回彈海綿，時尚設計，","categoryId":1008002,"counterPrice":66.00,"createTime":"2018-02-01 00:00:00","delFlag":false,"goodsSn":"1134030","id":1134030,"isHot":false,"isNew":true,"isOnSale":true,"keywords":"","name":"簡約知性記憶棉坐墊","picUrl":"http://yanxuan.nosdn.127.net/aa49dfe878becf768eddc4c1636643a6.png","retailPrice":46.00,"shareUrl":"","sort":12,"unit":"件","updateTime":"2018-02-01 00:00:00","virtualSales":10},{"actualSales":0,"brandId":0,"brief":"慢回彈海綿的呵護，萌趣添彩，","categoryId":1008002,"counterPrice":69.00,"createTime":"2018-02-01 00:00:00","delFlag":false,"goodsSn":"1134032","id":1134032,"isHot":false,"isNew":true,"isOnSale":true,"keywords":"","name":"趣味粉彩系列記憶棉坐墊","picUrl":"http://yanxuan.nosdn.127.net/8b30eeb17c831eba08b97bdcb4c46a8e.png","retailPrice":49.00,"shareUrl":"","sort":13,"unit":"件","updateTime":"2018-02-01 00:00:00","virtualSales":10},{"actualSales":0,"brandId":0,"brief":"100%桑蠶絲，絲滑潤膚","categoryId":1008009,"counterPrice":2619.00,"createTime":"2018-02-01 00:00:00","delFlag":false,"goodsSn":"1135002","id":1135002,"isHot":false,"isNew":true,"isOnSale":true,"keywords":"","name":"宮廷奢華真絲四件套","picUrl":"http://yanxuan.nosdn.127.net/45548f26cfd0c7c41e0afc3709d48286.png","retailPrice":2599.00,"shareUrl":"","sort":1,"unit":"件","updateTime":"2018-02-01 00:00:00","virtualSales":10},{"actualSales":0,"brandId":0,"brief":"自由海軍領探索未來夢","categoryId":1020003,"counterPrice":89.00,"createTime":"2018-02-01 00:00:00","delFlag":false,"goodsSn":"1135072","id":1135072,"isHot":false,"isNew":true,"isOnSale":true,"keywords":"","name":"經典海魂紋水手裙（嬰童）","picUrl":"http://yanxuan.nosdn.127.net/43e57d4208cdc78ac9c088f9b3e798f5.png","retailPrice":69.00,"shareUrl":"","sort":3,"unit":"件","updateTime":"2018-02-01 00:00:00","virtualSales":10},{"actualSales":0,"brandId":0,"brief":"經典海魂紋自由海軍領","categoryId":1020003,"counterPrice":89.00,"createTime":"2018-02-01 00:00:00","delFlag":false,"goodsSn":"1135073","id":1135073,"isHot":false,"isNew":true,"isOnSale":true,"keywords":"","name":"海魂紋哈衣水手服（嬰童）","picUrl":"http://yanxuan.nosdn.127.net/53052b04ae001d289c040e09ea92231c.png","retailPrice":69.00,"shareUrl":"","sort":4,"unit":"件","updateTime":"2018-02-01 00:00:00","virtualSales":10},{"actualSales":5,"brandId":0,"brief":"差旅好伴侶","categoryId":1032000,"counterPrice":119.00,"createTime":"2018-02-01 00:00:00","delFlag":false,"goodsSn":"1152031","id":1152031,"isHot":true,"isNew":true,"isOnSale":true,"keywords":"","name":"魔獸世界-伊利丹頸枕眼罩套裝","picUrl":"http://yanxuan.nosdn.127.net/fd6e78a397bd9e9804116a36f0270b0a.png","retailPrice":99.00,"shareUrl":"","sort":4,"unit":"件","updateTime":"2018-02-01 00:00:00","virtualSales":10},{"actualSales":5,"brandId":0,"brief":"桌面整理神器","categoryId":1032000,"counterPrice":519.00,"createTime":"2018-02-01 00:00:00","delFlag":false,"goodsSn":"1152095","id":1152095,"isHot":false,"isNew":true,"isOnSale":true,"keywords":"","name":"魔獸世界 聯盟·暴風城 堡壘收納盒","picUrl":"http://yanxuan.nosdn.127.net/c86b49f635fa141decebabbd0966a6ef.png","retailPrice":499.00,"shareUrl":"","sort":6,"unit":"件","updateTime":"2018-02-01 00:00:00","virtualSales":10},{"actualSales":0,"brandId":0,"brief":"3重透氣，清爽柔滑","categoryId":1008009,"counterPrice":479.00,"createTime":"2018-02-01 00:00:00","delFlag":false,"goodsSn":"1152161","id":1152161,"isHot":false,"isNew":true,"isOnSale":true,"keywords":"","name":"竹語絲麻印花四件套","picUrl":"http://yanxuan.nosdn.127.net/977401e75113f7c8334c4fb5b4bf6215.png","retailPrice":459.00,"shareUrl":"","sort":6,"unit":"件","updateTime":"2018-02-01 00:00:00","virtualSales":10}], categoryList=[{"createTime":"2020-12-08 23:09:12","delFlag":false,"iconUrl":"http://cdn.wayn.xin/9fc3c52571aa38a1466f114c2dc892fc.png","id":2,"jumpType":0,"name":"大牌手機","picUrl":"http://cdn.wayn.xin/2545dd00ca4575759024af2811949a9d.jpg","sort":1,"status":0,"updateTime":"2020-12-12 19:26:48","valueId":5,"valueUrl":"http://baidu.com"},{"createTime":"2020-12-06 13:27:54","delFlag":false,"iconUrl":"http://82.157.141.70/upload/2022/02/21/a23fa32c8f4004a8c9fbbb1784462163.jpg","id":1,"jumpType":0,"name":"滋補保健2","picUrl":"http://cdn.wayn.xin/d4de7172eb7ae4178ae4dafd6a973d8f.jpg","sort":2,"status":0,"updateTime":"2022-06-19 09:17:20","valueId":2},{"createTime":"2020-12-08 23:26:15","delFlag":false,"iconUrl":"http://cdn.wayn.xin/6bc0f8a131d2d16b8fc2004d4aa4860c.png","id":3,"jumpType":1,"name":"不銹鋼鍋","picUrl":"http://cdn.wayn.xin/314d87257f7a2ff03d5f4c5183797912.jpg","sort":2,"status":0,"updateTime":"2020-12-12 19:27:24","valueId":1036000},{"createTime":"2020-12-12 19:28:08","delFlag":false,"iconUrl":"http://cdn.wayn.xin/5a90531d901529967885279d7dc826e1.png","id":14,"jumpType":0,"name":"進口牛奶","picUrl":"http://cdn.wayn.xin/0b1f6ab63d5e222c52c83a2d0581e44c.jpg","sort":3,"status":0,"valueId":5},{"createTime":"2020-12-12 19:28:33","delFlag":false,"iconUrl":"http://cdn.wayn.xin/33530951827ca7e59940d51cda537d84.png","id":15,"jumpType":0,"name":"量販囤貨","picUrl":"http://cdn.wayn.xin/bb6daee3b3e51c3008db97585249f513.jpg","sort":4,"status":0,"valueId":2},{"createTime":"2020-12-12 19:28:50","delFlag":false,"iconUrl":"http://cdn.wayn.xin/7d337f25111b263b29d5d12589015c46.png","id":16,"jumpType":0,"name":"清潔用品","picUrl":"http://cdn.wayn.xin/be8995bda39d03b17349b8ec0dcab3d5.jpg","sort":5,"status":0,"valueId":2},{"createTime":"2020-12-12 19:29:10","delFlag":false,"iconUrl":"http://cdn.wayn.xin/2e632ec0173bb477dcdb601495e0412a.png","id":17,"jumpType":0,"name":"洗護用品","picUrl":"http://cdn.wayn.xin/53fb88c9d1245caa882aa3fc29187d0b.jpg","sort":6,"status":0,"valueId":4},{"createTime":"2020-12-12 19:29:28","delFlag":false,"iconUrl":"http://cdn.wayn.xin/942323c0e74677cf2aa15f09a1e63bca.png","id":18,"jumpType":0,"name":"日用百貨","picUrl":"http://cdn.wayn.xin/8587f91db2edcb43e57da9835cc7ec76.jpg","sort":7,"status":0,"valueId":2},{"createTime":"2020-12-12 19:29:46","delFlag":false,"iconUrl":"http://cdn.wayn.xin/18d9d860ba9b8b28522e050f11a8a8e0.png","id":19,"jumpType":0,"name":"明星乳膠","picUrl":"http://cdn.wayn.xin/65273c7fb2273e90958e92626248a90a.jpg","sort":8,"status":0,"valueId":6},{"createTime":"2020-12-12 19:30:15","delFlag":false,"iconUrl":"http://cdn.wayn.xin/7c790577afda91eebc3c95586e190957.png","id":20,"jumpType":0,"name":"口碑好物","picUrl":"http://cdn.wayn.xin/210011b35be4ceee39e6a466b40b8e22.jpg","sort":9,"status":0,"updateTime":"2021-04-01 20:13:08","valueId":5}], expire_time=1669549170235, hotGoodsList=[{"actualSales":1,"brandId":1001045,"brief":"一級桑蠶絲，吸濕透氣柔軟","categoryId":1036000,"counterPrice":719.00,"createTime":"2018-02-01 00:00:00","delFlag":false,"goodsSn":"1006013","id":1006013,"isHot":true,"isNew":false,"isOnSale":true,"keywords":"","name":"雙宮繭桑蠶絲被 空調被","picUrl":"http://yanxuan.nosdn.127.net/583812520c68ca7995b6fac4c67ae2c7.png","retailPrice":699.00,"shareUrl":"","sort":7,"unit":"件","updateTime":"2021-08-08 11:19:36","virtualSales":10},{"actualSales":1,"brandId":1001045,"brief":"雙層子母被，四季皆可使用","categoryId":1008008,"counterPrice":14199.00,"createTime":"2018-02-01 00:00:00","delFlag":false,"goodsSn":"1006014","id":1006014,"isHot":true,"isNew":false,"isOnSale":true,"keywords":"","name":"雙宮繭桑蠶絲被 子母被","picUrl":"http://yanxuan.nosdn.127.net/2b537159f0f789034bf8c4b339c43750.png","retailPrice":1399.00,"shareUrl":"","sort":15,"unit":"件","updateTime":"2018-02-01 00:00:00","virtualSales":10},{"actualSales":6,"brandId":1001000,"brief":"加大加厚，雙色精彩","categoryId":1036000,"counterPrice":219.00,"createTime":"2018-02-01 00:00:00","delFlag":false,"goodsSn":"1011004","id":1011004,"isHot":true,"isNew":false,"isOnSale":true,"keywords":"","name":"色織精梳AB紗格紋空調被","picUrl":"http://yanxuan.nosdn.127.net/0984c9388a2c3fd2335779da904be393.png","retailPrice":199.00,"shareUrl":"","sort":2,"unit":"件","updateTime":"2018-02-01 00:00:00","virtualSales":10},{"actualSales":6,"brandId":0,"brief":"共享親密2人時光","categoryId":1008008,"counterPrice":219.00,"createTime":"2018-02-01 00:00:00","delFlag":false,"goodsSn":"1019002","id":1019002,"isHot":true,"isNew":false,"isOnSale":true,"keywords":"","name":"升級款護頸雙人記憶枕","picUrl":"http://yanxuan.nosdn.127.net/0118039f7cda342651595d994ed09567.png","retailPrice":199.00,"shareUrl":"","sort":10,"unit":"件","updateTime":"2018-02-01 00:00:00","virtualSales":10},{"actualSales":6,"brandId":0,"brief":"健康保護枕","categoryId":1008008,"counterPrice":119.00,"createTime":"2018-02-01 00:00:00","delFlag":false,"goodsSn":"1019006","id":1019006,"isHot":true,"isNew":false,"isOnSale":true,"keywords":"","name":"植物填充護頸夜交藤枕","picUrl":"http://yanxuan.nosdn.127.net/60c3707837c97a21715ecc3986a744ce.png","retailPrice":99.00,"shareUrl":"","sort":7,"unit":"件","updateTime":"2018-02-01 00:00:00","virtualSales":10},{"actualSales":6,"brandId":0,"brief":"厚實舒適","categoryId":1008001,"counterPrice":59.00,"createTime":"2018-02-01 00:00:00","delFlag":false,"goodsSn":"1021000","id":1021000,"isHot":true,"isNew":false,"isOnSale":true,"keywords":"被","name":"埃及進口長絨棉毛巾","picUrl":"http://yanxuan.nosdn.127.net/7191f2599c7fe44ed4cff7a76e853154.png","retailPrice":39.00,"shareUrl":"","sort":7,"unit":"條","updateTime":"2018-02-01 00:00:00","virtualSales":10},{"actualSales":6,"brandId":1001020,"brief":"浪漫毛線繡球，簡約而不簡單","categoryId":1008009,"counterPrice":319.00,"createTime":"2018-02-01 00:00:00","delFlag":false,"goodsSn":"1022000","id":1022000,"isHot":true,"isNew":false,"isOnSale":true,"keywords":"","name":"意式毛線繡球四件套","picUrl":"http://yanxuan.nosdn.127.net/5350e35e6f22165f38928f3c2c52ac57.png","retailPrice":299.00,"shareUrl":"","sort":18,"unit":"件","updateTime":"2018-02-01 00:00:00","virtualSales":10},{"actualSales":32,"brandId":1001000,"brief":"柔軟紗布，嬰童可用","categoryId":1036000,"counterPrice":269.00,"createTime":"2018-02-01 00:00:00","delFlag":false,"goodsSn":"1027004","id":1027004,"isHot":true,"isNew":false,"isOnSale":true,"keywords":"","name":"色織六層紗布夏涼被","picUrl":"http://yanxuan.nosdn.127.net/6252f53aaf36c072b6678f3d8c635132.png","retailPrice":249.00,"shareUrl":"","sort":3,"unit":"件","updateTime":"2018-02-01 00:00:00","virtualSales":10},{"actualSales":32,"brandId":0,"brief":"原生苦蕎，健康護頸","categoryId":1008008,"counterPrice":119.00,"createTime":"2018-02-01 00:00:00","delFlag":false,"goodsSn":"1036002","id":1036002,"isHot":true,"isNew":false,"isOnSale":true,"keywords":"","name":"高山苦蕎麥枕","picUrl":"http://yanxuan.nosdn.127.net/ffd7efe9d5225dff9f36d5110b027caa.png","retailPrice":99.00,"shareUrl":"","sort":5,"unit":"件","updateTime":"2018-02-01 00:00:00","virtualSales":10},{"actualSales":32,"brandId":0,"brief":"5cm記憶綿的親密包裹","categoryId":1008008,"counterPrice":619.00,"createTime":"2018-02-01 00:00:00","delFlag":false,"goodsSn":"1037011","id":1037011,"isHot":true,"isNew":false,"isOnSale":true,"keywords":"","name":"安睡慢回彈記憶綿床墊","picUrl":"http://yanxuan.nosdn.127.net/a03ea6f4509439acdafcb7ceba1debe0.png","retailPrice":599.00,"shareUrl":"","sort":22,"unit":"件","updateTime":"2018-02-01 00:00:00","virtualSales":10}]}]
2022-11-27 21:29:48.336 [9d919fb6d33c4652ba28ff87ae210809_12] [http-nio-82-exec-3] [DEBUG] c.w.c.c.m.s.G.selectGoodsListPage_mpCount:137 debug - ==> Preparing: SELECT COUNT(*) AS total FROM shop_goods WHERE del_flag = 0 AND is_on_sale = 1
2022-11-27 21:29:48.387 [9d919fb6d33c4652ba28ff87ae210809_12] [http-nio-82-exec-3] [DEBUG] c.w.c.c.m.s.G.selectGoodsListPage_mpCount:137 debug - ==> Parameters:
2022-11-27 21:29:48.426 [9d919fb6d33c4652ba28ff87ae210809_12] [http-nio-82-exec-3] [DEBUG] c.w.c.c.m.s.G.selectGoodsListPage_mpCount:137 debug - <== Total: 1
2022-11-27 21:29:48.430 [9d919fb6d33c4652ba28ff87ae210809_12] [http-nio-82-exec-3] [DEBUG] c.w.c.c.m.s.G.selectGoodsListPage:137 debug - ==> Preparing: select id, goods_sn, name, pic_url, counter_price, retail_price, actual_sales, virtual_sales from shop_goods WHERE del_flag = 0 and is_on_sale = 1 order by create_time desc LIMIT ?
2022-11-27 21:29:48.452 [9d919fb6d33c4652ba28ff87ae210809_12] [http-nio-82-exec-3] [DEBUG] c.w.c.c.m.s.G.selectGoodsListPage:137 debug - ==> Parameters: 6(Long)
2022-11-27 21:29:48.476 [9d919fb6d33c4652ba28ff87ae210809_12] [http-nio-82-exec-3] [DEBUG] c.w.c.c.m.s.G.selectGoodsListPage:137 debug - <== Total: 6
最后分析上訴日志：通過86c76336100c414dbe9217aeb099ccd5實作介面呼叫追蹤，通過12用戶ID，實作用戶呼叫追蹤
七. alibaba excel匯出時自定義格式轉換優雅實作
官網介紹：EasyExcel 是一個基于Java的簡單、省記憶體的讀寫Excel的開源專案，在盡可能節約記憶體的情況下支持讀寫百M的Excel，
EasyExcel 是 alibaba 出的一個基于 java poi 得excel通用處理類別庫，他的優勢在于記憶體消耗，對比 easypoi 方案，EasyExcel 在記憶體消耗、知名度（大廠光環）上更出眾些，
博主在使用程序中發現匯出excel，官網對自定義格式欄位提供了 converter 介面，但只簡單提供了CustomStringStringConverter 類代碼，達不到博主想要得優雅要求，如下：
public class CustomStringStringConverter implements Converter<String> {
@Override
public Class<?> supportJavaTypeKey() {
return String.class;
}
@Override
public CellDataTypeEnum supportExcelTypeKey() {
return CellDataTypeEnum.STRING;
}
/**
* 這里讀的時候會呼叫
*
* @param context
* @return
*/
@Override
public String convertToJavaData(ReadConverterContext<?> context) {
return "自定義：" + context.getReadCellData().getStringValue();
}
/**
* 這里是寫的時候會呼叫 不用管
*
* @return
*/
@Override
public WriteCellData<?> convertToExcelData(WriteConverterContext<String> context) {
return new WriteCellData<>(context.getValue());
}
}
在以上代碼中，打個比方想要實作性別欄位得自定義格式轉換，就需要在convertToExcelData方法中，添加如下代碼
@Override
public WriteCellData<?> convertToExcelData(WriteConverterContext<String> context) {
String value = https://www.cnblogs.com/wayn111/archive/2022/11/30/context.getValue();
if ("man".equals(value)) {
return new WriteCellData<>("男");
} else {
return new WriteCellData<>("女");
}
}
可以看到，非常得不優雅，對于這種型別欄位，博主習慣使用列舉類來定義欄位所有型別，然后將列舉類轉換為 map(value,desc) 結構，就可以優雅得實作這個自定義格式得需求
/**
* 一、先定義int欄位抽象轉換類，實作通用轉換邏輯
*/
public abstract class AbstractIntConverter implements Converter<Integer> {
abstract List<ConverterDTO> getArr();
public WriteCellData<?> convertToExcelData(Integer value, ExcelContentProperty contentProperty, GlobalConfiguration globalConfiguration) {
List<ConverterDTO> values = getArr();
Map<Integer, String> map = values.stream().collect(toMap(ConverterDTO::getType, ConverterDTO::getDesc));
String result = map.getOrDefault(value, "");
return new WriteCellData<>(result);
}
static class ConverterDTO {
private Integer type;
private String desc;
public Integer getType() {
return type;
}
public void setType(Integer type) {
this.type = type;
}
public String getDesc() {
return desc;
}
public void setDesc(String desc) {
this.desc = desc;
}
public ConverterDTO(Integer type, String desc) {
this.type = type;
this.desc = desc;
}
}
}
/**
* 二、定義通用狀態欄位轉換類
*/
public class StatusConverter extends AbstractIntConverter {
@Override
List<ConverterDTO> getArr() {
StatusEnum[] values = StatusEnum.values();
return Arrays.stream(values).map(sexEnum -> new ConverterDTO(sexEnum.getType(), sexEnum.getDesc())).toList();
}
/**
* 狀態列舉
*/
enum StatusEnum {
MAN(0, "啟用"),
WOMAN(1, "禁用");
private Integer type;
private String desc;
StatusEnum(Integer type, String desc) {
this.type = type;
this.desc = desc;
}
public Integer getType() {
return type;
}
public String getDesc() {
return desc;
}
}
}
最后再匯出 ExcelProperty 中甜膩加 StatusConverter ，就優雅得實作了自定義格式得需求
public class User extends BaseEntity {
...
/**
* 用戶狀態 0 啟用 1 禁用
*/
@ExcelProperty(value = "https://www.cnblogs.com/wayn111/archive/2022/11/30/用戶狀態", converter = StatusConverter.class)
private Integer userStatus;
...
}
八. Springboot 默認redis客戶端lettuce經常連接超時解決方案
不知道大家有沒有遇到這種情況，線上專案使用 lettuce 客戶端，當操作 redis 得介面一段時間沒有呼叫后（比如30分鐘），再次呼叫 redis 操作后，就會遇到連接超時得問題，導致介面例外，博主直接給出分析程序：
- 通過wireshark抓包工具，發現專案中
redis連接創建后，一段時間未傳輸資料后，客戶端發送psh包，未收到服務端ack包，觸發tcp得超時重傳機制，在重傳次數重試完后，最終客戶端主動關閉了連接，
到這里我們就知道這個問題，主要原因在于服務端沒有回復客戶端（比如tcp引數設定、防火墻主動關閉等，都是針對一段時間內沒有資料傳輸得tcp連接會做關閉處理），造成了客戶端得連接超時
面對這個問題有三種解決方案：
- redis操作例外后進行重試，這篇文章有介紹 生產環境Redis連接，長時間無回應被服務器斷開問題
- 啟用一個心跳定時任務，定時訪問
redis，保持redis連接不被關閉，簡而言之，就是寫一個定時任務，定時呼叫redis得get命令，進而保活redis連接 - 基于Springboot 提供得
LettuceClientConfigurationBuilderCustomizer自定義客戶端配置，博主這里主要針對第三種自定義客戶端配置來講解一種優雅得方式
Springboot 專案中關于 lettuce 客戶端得自動配置是沒有啟用保活配置得，要啟用得話代碼如下：
/**
* 自定義lettuce客戶端配置
*
* @return LettuceClientConfigurationBuilderCustomizer
*/
@Bean
public LettuceClientConfigurationBuilderCustomizer lettuceClientConfigurationBuilderCustomizer() {
return clientConfigurationBuilder -> {
LettuceClientConfiguration clientConfiguration = clientConfigurationBuilder.build();
ClientOptions clientOptions = clientConfiguration.getClientOptions().orElseGet(ClientOptions::create);
ClientOptions build = clientOptions.mutate().build();
SocketOptions.KeepAliveOptions.Builder builder = build.getSocketOptions().getKeepAlive().mutate();
// 保活配置
builder.enable(true);
builder.idle(Duration.ofSeconds(30));
SocketOptions.Builder socketOptionsBuilder = clientOptions.getSocketOptions().mutate();
SocketOptions.KeepAliveOptions keepAliveOptions = builder.build();
socketOptionsBuilder.keepAlive(keepAliveOptions);
SocketOptions socketOptions = socketOptionsBuilder.build();
ClientOptions clientOptions1 = ClientOptions.builder().socketOptions(socketOptions).build();
clientConfigurationBuilder.clientOptions(clientOptions1);
};
}
添加 lettuce 客戶端的自定義配置，在 KeepAliveOptions 中啟用 enable ，這樣 lettuce 客戶端就會在tcp協議規范上啟用 keep alive 機制自動發送心跳包
九. redis客戶端lettuce啟用epoll
直接給 官網連接，配置很簡單，添加一個 netty-all 得依賴，lettuce 會自動檢測專案系統是否支持 epoll（linux 系統支持），并且是否有netty-transport-native-epoll依賴（ netty-all 包含 netty-transport-native-epoll ），都滿足得話就會自動啟用 epoll 事件回圈，進一步提升系統性能
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-all</artifactId>
</dependency>
十. Springboot web專案優雅停機
web專案配置了優雅停機后，在重啟jar包，或者容器時可以防止正在活動得執行緒被突然停止（ kill -9 無解，請不要使用這個引數殺線上行程，docker compose 專案盡量不要用 docker-compose down 命令關閉專案，使用 docker-compose rm -svf 可以觸發優雅停機），造成用戶請求失敗，在此期間允許完成現有請求但不允許新請求，配置如下：
server: shutdown: "graceful"
十一. nginx配置通用請求后綴
先說下這個配置產生得前提，博主公司pc客戶專案是基于 electron 打包得網頁專案，每次專案大版本更新時，為了做好兼容性，防止客戶端網頁快取等，會使用一個新網頁地址，打個比方：
老網頁地址，v1.1.0 版本網頁訪問地址：http://api.dev.com/pageV110
新網頁地址，v1.2.0 版本網頁訪問地址：http://api.dev.com/pageV120
那么專案得nginx配置則則需要新加一個 v1.2.0 得配置如下：
server {
listen 80;
server_name api.dev.com;
client_max_body_size 10m;
# 老網頁v1.1.0配置
location ~ ^/pageV110 {
alias /home/wwwroot/api.dev.com/pageV110;
index index.html index.htm;
}
# 新網頁v1.2.0配置
location ~ ^/pageV120 {
alias /home/wwwroot/api.dev.com/pageV120;
index index.html index.htm;
}
}
那么博主在每次專案發布得時候就需要配合前端發版，配置一個新網頁，故產生了這個通用配置得需求，如下：
server {
listen 80;
server_name api.dev.com;
client_max_body_size 10m;
# 配置正則localtion
location ~ ^/pageV(.*) {
set $s $1; # 定義后綴變數
alias /home/wwwroot/api.dev.com/pageV$s;
index index.html index.htm;
}
}
在 nginx 組態檔語法中，location 陳述句可以使用正則運算式，定義 set $s $1 變數，實作了通用配置
十二. 關于開發人員的自我提升和突破
博主這里主要總結了四點：
- 多和他人溝通，溝通能把復雜問題簡單化，有時候開發階段一個需求多問幾句，可以減少因為個人理解差異導致的需求不一致問題，進而減少開發時間
- 建立長短期目標，觀看技術視頻、書籍給自己充電，比如7天利用業余時間看完一本電子書，三十天從零開始一個新專案等
- 善于總結，對于專案中的疑難bug，踩坑點要有記錄，防止下次遇到再掉坑里
- 敢于嘗試、擔責，對專案、代碼里明確不合理的地方要敢于跟他人溝通，修改問題代碼，達到優化目的，對于自己造成的問題要承擔，不要推卸責任，對于線上問題要重視，優先解決線上問題，
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