可执行jar的外部属性文件

Question

I'm trying to add an external properties file to an executable jar, but not in succeed for now.

Question : Is it impossible to include an external properties file into an executable jar?

When I run my program locally, with putting batch.properties under src/main/resources , it works fine. But it fails after deploying the jar and batch.properties , linking it under /etc/init.d/ , putting the jar and batch.properties

/usr/local/myapp/myapp.jar
/usr/local/myapp/batch.properties
/etc/init.d/my-app    --(symlink)-->   /usr/local/myapp/myapp.jar

my-app can be executable just like an usual service:

/etc/init.d/my-app start

But it says that some beans cannot be instantiated due to missing placeholders.

Invalid bean definition with name 'dataSource' defined in class path resource [batch.xml]: Could not resolve placeholder 'spring.datasource.batch.class_name' in string value "${spring.datasource.batch.class_name}"; nested exception is java.lang.IllegalArgumentException: Could not resolve placeholder 'spring.datasource.batch.class_name' in string value "${spring.datasource.batch.class_name}"

My pom.xml is like this:

<project ...>
  // Some other definitions...

  <build>
    <resources>
      <resource>
        <directory>src/main/resources</directory>
      </resource>
    </resources>
    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
        <configuration>
          <mainClass>my.project.Bootstrap</mainClass>
          <executable>true</executable>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

And the Spring setting is just like this:

<?xml version="1.0" encoding="UTF-8"?>
<beans ...">
  <context:property-placeholder location="classpath*:batch.properties" />
  <!-- Some bean definitions -->
</beans>

Any help or comments would be appreciated so much.

EDIT

I couldn't succeed it for now, but alternately I decided to split profiles and include a properties file accordingly into the executable jar.

However it's better to be able to read an external properties file, any help would still be welcomed.

Answer 1

You can add an external properties file next to the .jar provided that you call it application.properties .

If you cannot rename the properties file, you can also give the path of the external properties file as an option :

java -jar myproject.jar --spring.config.location=/path/to/batch.properties

#Or for executable jars
./myproject.jar --spring.config.location=/path/to/batch.properties

You can also create a symlink application.properties -> batch.properties .

See Externalized configuration .

EDIT

This is my maven config :

<build>
  <plugins>
    <plugin>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-maven-plugin</artifactId>
      <version>1.3.3.RELEASE</version>
      <configuration>
        <executable>true</executable>
      </configuration>
      <executions>
        <execution>
          <goals>
            <goal>repackage</goal>
          </goals>
        </execution>
      </executions>
    </plugin>
  </plugins>
</build>

After mvn clean install, I get 2 jars :

backend/target [ ll
total 53M
-rwxr--r-- 1 adenoyelle adenoyelle  53M avril 22 10:56 backend-1.0-SNAPSHOT.jar
-rw-r--r-- 1 adenoyelle adenoyelle 353K avril 22 10:56 backend-1.0-SNAPSHOT.jar.original

Then, I copy the first jar to the destination folder and place a configuration.properties next to it :

backend@[...]:~/backend$ ll
total 53900
drwxrwxr-x 2 backend backend     4096 Apr 21 13:56 ./
drwxr-xr-x 6 backend backend     4096 Apr 21 13:56 ../
-rw-rw-r-- 1 backend backend      511 Apr 20 16:13 application.properties
-rwxr--r-- 1 backend backend 55175294 Apr 20 19:06 backend-1.0-SNAPSHOT.jar*
lrwxrwxrwx 1 backend backend       24 Apr 20 19:20 backend -> backend-1.0-SNAPSHOT.jar*
-rw-r--r-- 1 backend backend      179 Apr 20 19:26 backend.service

You can see that I also created a file called backend.service in order to install the jar as a service via systemd .

Here is the content of the file :

[Unit]
Description=backend
After=syslog.target

[Service]
User=backend
ExecStart=/home/backend/backend
SuccessExitStatus=143

[Install]
WantedBy=multi-user.target

And there is a symlink to this file in /etc/systemd/system :

backend@[...]:/etc/systemd/system$ ll | grep backend
lrwxrwxrwx  1 root root   37 Apr 20 19:23 backend.service -> /home/backend/backend.service