springboot放到linux启动报错：The temporary upload location [/tmp/tomcat.8524616412347407692.8111/work/Tomcat/localhost/ROOT/asset] is not valid

1、背景

笔者的springboot在一个非root用户环境下运行，这种环境下可以保证不被潜在的jar/开源框架漏洞提权。

比如在防火墙上把外网访问来的443端口映射到本地8443的java web端口。（注意对外服务的80-1024端口需要root权限才能申请），

具体映射方法可参考：Linux下使用iptables配置防火墙端口转发 。由于是受限用户遇到一些问题：

org.springframework.web.multipart.MultipartException: Failed to parse multipart servlet request; nested exception is java.io.IOException: The temporary upload location [/tmp/tomcat.8524616412347407692.8111/work/Tomcat/localhost/ROOT/asset] i
s not valid
        at org.springframework.web.multipart.support.StandardMultipartHttpServletRequest.handleParseFailure(StandardMultipartHttpServletRequest.java:122)
        at org.springframework.web.multipart.support.StandardMultipartHttpServletRequest.parseRequest(StandardMultipartHttpServletRequest.java:113)
        at org.springframework.web.multipart.support.StandardMultipartHttpServletRequest.<init>(StandardMultipartHttpServletRequest.java:86)
        at org.springframework.web.multipart.support.StandardServletMultipartResolver.resolveMultipart(StandardServletMultipartResolver.java:93)
        at org.springframework.web.servlet.DispatcherServlet.checkMultipart(DispatcherServlet.java:1128)
        at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:960)
        at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925)
        at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974)
        at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:877)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)
        at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
        at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
        at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.filterAndRecordMetrics(WebMvcMetricsFilter.java:158)
        at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.filterAndRecordMetrics(WebMvcMetricsFilter.java:126)
        at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:111)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
        at org.springframework.boot.actuate.web.trace.servlet.HttpTraceFilter.doFilterInternal(HttpTraceFilter.java:84)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
        at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
        at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
        at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
        at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
                                            

解决方法，根据SpringBoot版本不同设置

spring.servlet.multipart.location=YOUR_TEMP_LOCATION_PATH
或者
spring.http.multipart.location=YOUR_TEMP_LOCATION_PATH

笔者使用yaml配置文件，如下

起初经过如下一些设置，均无效

1、asset

2、./asset 对应结果：The temporary upload location [/tmp/tomcat.3611170690354284212.8111/work/Tomcat/localhost/ROOT/./asset] is not valid

后设置成绝对路径，这个绝对路径从JVM系统属性里获取ASSET_HOME属性，ASSET_HOME属性在启动类里面设置，如下：

import com.netmarch.web.common.mybatis.MyBatisConfig;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.system.ApplicationHome;
import org.springframework.cache.annotation.CacheConfig;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.scheduling.annotation.EnableAsync;

import java.io.File;
import java.nio.file.Path;

@EnableAsync
@EnableCaching
@CacheConfig
@EnableAutoConfiguration
@SpringBootApplication(exclude = {
        MyBatisConfig.class
},scanBasePackages = "com.xxx")
public class WebApplication{

    public static void main(String[] args) {

        ApplicationHome home = new ApplicationHome(WebApplication.class);
        // returns the folder where the jar is. This is what I wanted.
        File rootFolder = home.getDir();
        Path path = rootFolder.toPath().normalize().toAbsolutePath();
        System.setProperty("ASSET_HOME",path.toString());

        SpringApplication.run(WebApplication.class, args);
    }
}

其他参考：

https://spring.hhui.top/spring-blog/2019/02/13/190213-SpringBoot%E6%96%87%E4%BB%B6%E4%B8%8A%E4%BC%A0%E5%BC%82%E5%B8%B8%E4%B9%8B%E6%8F%90%E7%A4%BAThe-temporary-upload-location-xxx-is-not-valid/