maven-shade-plugin&java.lang.runtimeexception: unable to find function

<properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.encoding>UTF-8</maven.compiler.encoding>
        <java.version>10</java.version>
        <maven.compiler.source>10</maven.compiler.source>
        <maven.compiler.target>10</maven.compiler.target>
 </properties>

在Maven中，主要有3个插件可以用来打包：

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1.maven-jar-plugin，默认的打包插件，用来打普通的project JAR包；

2.maven-shade-plugin，用来打可执行JAR包，也就是所谓的fat JAR包；

3.maven-assembly-plugin，支持自定义的打包结构，也可以定制依赖项等。

可执行jar包(maven-shade-plugin)

<project>
   <groupId>shade.test</groupId>
    <artifactId>shade.test</artifactId>
    <version>1.0-SNAPSHOT</version>
  ...
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-shade-plugin</artifactId>
        <version>3.0.0</version>
        <executions>
          <execution>
            <phase>package</phase>
            <goals>
              <goal>shade</goal>
            </goals>
            <configuration>
              <transformers>
                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                  <mainClass>Main</mainClass>
                </transformer>
              </transformers>
            </configuration>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
  ...
</project>

https://blog.csdn.net/u011624157/article/details/118077267

java.lang.runtimeexception: unable to find function

https://sourceforge.net/p/geotools/mailman/geotools-gt2-users/thread/19998467.post@talk.nabble.com/

I can help with that one ... we make use of Factory Service Provider 
Interface (ie Factory SPI) which makes use of META_INF/services/* (a 
folder in your jar that advertises all the services the jar offers - 
including the length function).

So when you do mvn assembly - you will need to make sure the 
META_INF/services files are all merged up (no I don't know how to do this).

The length function is being called when you make an attribute type; the 
shapefile header has a limitation that strings can only be 256 
characters long; we represent that as a restriction - the restriction 
that "length( . ) < 256".

我可以帮你。。。我们使用工厂服务提供商接口（即工厂SPI），使用META_INF/services/*（a您的jar中的文件夹，用于宣传jar提供的所有服务-包括长度函数）。
因此，当你进行mvn组装时，你需要确保META_INF/services文件都被合并了（不，我不知道怎么做）。
当您创建属性类型时，将调用length函数；这个shapefile头具有字符串只能为256的限制字符长；我们将其表示为一种限制“长度（.）<256”。

I have exactly the same problem that John had from the same source,
implementing the "How to read a shapefile example". I have read Jody's
response and tried to implement it. I don't have any problem including
something in the META-INF/servies folder in the jar. I know how to do that.
But I haven't been able to figure out what to include. I tried following the
directions in the API for implementing a DataStoreFactorySpi. These suggest
the following:

我有和约翰完全相同的问题，来自同一个来源，实现“如何读取形状文件示例”。我读过乔迪的响应并尝试实施它。我没有任何问题，包括jar中META-INF/servies文件夹中的某些内容。我知道怎么做。
但我一直没能弄清楚该包括什么。我试着跟随API中有关实现DataStoreFactorySpi的说明。这些建议以下内容：

[Begin quote from API]
Implementation Notes
An instance of this interface should exist for all data stores which want to
take advantage of the dynamic plug-in system. In addition to implementing
this factory interface each DataStore implementation should have a services
file:
META-INF/services/org.geotools.data.DataStoreFactorySpi
The file should contain a single line which gives the full name of the
implementing class.
example:
e.g. org.geotools.data.mytype.MyTypeDataSourceFacotry
The factories are never called directly by client code, instead the
DataStoreFinder class is used.
[/End quote from API]

I don't know if this is what Jody was referring to, but in any event I
haven't been able to find anything that works. 

Can anyone provide more detail about what is required to get 
org.geotools.filter.FunctionFinder.findFunction(FunctionFinder.java:xx) to
be able to find the Length function.

Will