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错误信息如下：java.lang.RuntimeException: java.io.IOException: 权限不够 at org.apache.poi.xssf.streaming.SXSSFWorkbook.createAndRegisterSXSSFSheet(SXSSFWorkbook.java:662) at org.apache.poi.xssf.streaming.SXSSFWorkbook.createSheet(SXSSFWorkbook.java:679) at org.apache

1、利用递归方法来遍历文件夹2、引入com.google.code.gson <dependency> <groupId>com.google.code.gson</groupId> <artifactId>gson</artifactId> <version>2.8.2</version> </dependency...

1、继承Thread类class Ticket extends Thread { private static int tick = 100; public void run() { while (true) { System.out.println(Thread.currentThread().getName() + "sale:" + tick--); if

synchronizedsynchronized是java提供的专业解决线程安全问题的'锁' 只需在synchronized（对象）{} 对象如同锁、持有锁的线程可以在同步中执行、没有持有锁的线程即使获得cup的执行权也进不去 因为没有获得锁。class TicketRun implements Runnable { private int tick = 100; private st

synchronized在共享的函数前声明即可class Bank { private int sum = 0; public synchronized void add(int n) { sum += n; System.out.println("sum=" + sum); }}class Cus implements Runnable { private Bank

1、引入 pom.xml 文件<dependency> <groupId>org.jsoup</groupId> <artifactId>jsoup</artifactId> <version>1.12.1</version></...