Source of the problem

Error report when starting Tomcat

Solve the problem of changing the settings in idea

Correct setting
wrong setting
this will lead to problems in compilation, because the default setting is consistent with the language level

Error statuslogger no log4j2 configuration file found. Using default configuration: logging only errors to the console

Create a new resources folder in the project and add the log4j2. XML file as follows

<?xml version="1.0" encoding="UTF-8"?>
<Configuration>
    <Appenders>
        <Console name="STDOUT" target="SYSTEM_OUT">
            <PatternLayout pattern="%d %-5p [%t] %C{2} (%F:%L) - %m%n"/>
        </Console>
        <RollingFile name="RollingFile" fileName="logs/strutslog1.log"
                     filePattern="logs/$${date:yyyy-MM}/app-%d{MM-dd-yyyy}-%i.log.gz">
            <PatternLayout>
                <Pattern>%d{MM-dd-yyyy} %p %c{1.} [%t] -%M-%L- %m%n</Pattern>
            </PatternLayout>
            <Policies>
                <TimeBasedTriggeringPolicy />
                <SizeBasedTriggeringPolicy size="1 KB"/>
            </Policies>
            <DefaultRolloverStrategy fileIndex="max" max="2"/>
        </RollingFile>
    </Appenders>
    <Loggers>
        <Logger name="com.opensymphony.xwork2" level="WAN"/>
        <Logger name="org.apache.struts2" level="WAN"/>
        <Root level="warn">
            <AppenderRef ref="STDOUT"/>
        </Root>
    </Loggers>

</Configuration>

Select user entries in the classpath of the project corresponding to run – run configurations, click Advanced, and select add folder to add the Resources folder.

1. Cause of error:

When the resttemplate is used to call the third-party API, the local test is normal, but when it is deployed to the server, it will report: Dan, 19:06 org.springframework.web . client.ResourceAccessException : I/O error on POST request for "XXX": No route to host (Host unreachable); nested exception is java.net.NoRouteToHostException : no route to host (host unreachable) , at first, I thought that the timeout was not set, so I configured it through online methods

 SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();
 requestFactory.setConnectTimeout(10*1000);
 requestFactory.setReadTimeout(10*1000);
 RestTemplate rest = new RestTemplate(requestFactory);	

 HttpComponentsClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory();
 requestFactory.setConnectTimeout(10*1000);
 requestFactory.setReadTimeout(10*1000);
 RestTemplate rest = new RestTemplate(requestFactory);