ustbbsy的博客

Difference between Array and ArrayListSimilaritiesArray and ArrayList both are used for storing elements. Array and ArrayList both can store null values. They can have duplicate values. They do not preserve the order of elements.The following table

package dataStructure;import java.util.HashMap;import java.util.Iterator;import java.util.Map;public class learnMap { public static void main(String[] args){ Map<String, String> map = new HashMap<String, String>(); .

准备 kafkahttp://kafka.apache.org/downloads zookperhttps://downloads.apache.org/zookeeper/zookeeper-3.5.8/ Wgethttps://mirrors.tuna.tsinghua.edu.cn/apache/kafka/2.6.0/kafka_2.12-2.6.0.tgz安装zookeeper 解压 tar -zxvf apache-zookeeper-3....

@RequestMapping(path = "/user")@RequestMapping(path="/login",method=RequestMethod.GET)org.springframework.web.bind.annotation.RequestMethod来定义浏览器请求的方式。RequestMethod. GET POST PUT DELETE 注解的位置 注解在方法上 @Controllerp...

作用在类上的注解 @Service： 用于标注业务层的组件 @Controller: 用于标注控制层组件 @Component: 当不知道当前类属于哪类时(不属于@Controller、@Services等时)，就可以标注为@Component，用于标注泛指组件 @Repository：用于标注数据层组件 作用在属性或方法上的注解 @Autowired @Resource ...

工具是intellij idea在src -> main 下新建文件夹resources 在resources文件夹下新建 log4j2.xml文件log4j2.xml的文件内容如下<?xml version="1.0" encoding="UTF-8"?><Configuration> <Appenders> <Console name="STDOUT" target="SYSTEM_OUT">