java something necessary records

 

About timeout unusual record 2019-08-07

SocketTimeoutException: 
If the request succeeds, but beyond a certain time no return value

ConnectTimeoutException: 
If you can not find ip address

Use @data of 2019-08-07

1. Press according @data plug member
2. In the pom file, add the following dependence

<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
</dependency>
    

map traversal way 2019-08-07

for(Map.Entry<String,Student> entry: map.entrySet()){
    System.out.println(entry.getKey()+""+entry.getValue());
}
for(String key:map.keySet()){
    System.out.println(key+""+map.get(key));
}