问题
I am writing a simple custom annotation in Java and running into a problem with it. Here is the main parts of my code.
LogMeCustomAnnotation.java
package fun.n.learn.annotation;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
// We need this annotation only till before compilation.
@Retention(RetentionPolicy.SOURCE)
// This is a simple custom annotation.
public @interface LogMeCustomAnnotation {
}
LogMeCustomAnnotationProcessor.java
package fun.n.learn.annotation;
import java.util.Set;
import javax.annotation.processing.AbstractProcessor;
import javax.annotation.processing.Messager;
import javax.annotation.processing.RoundEnvironment;
import javax.annotation.processing.SupportedAnnotationTypes;
import javax.lang.model.element.TypeElement;
import javax.tools.Diagnostic;
// List the custom annotations that are supported.
@SupportedAnnotationTypes({ "fun.n.learn.annotation.LogMeCustomAnnotation" })
// Extend AbstractProcessor. This will let you process.
public class LogMeCustomAnnotationProcessor extends AbstractProcessor {
@Override
public boolean process(Set<? extends TypeElement> annotations,
RoundEnvironment roundEnv) {
Messager messager = processingEnv.getMessager();
messager.printMessage(Diagnostic.Kind.NOTE, "I was here.");
// TODO: Put some meaningful code here. Right now just get it to work.
// return false;
// We have already handled these annotations. No more. So return true.
return true;
}
}
/src/main/resources/META-INF/services/javax.annotation.processing.Processor
fun.n.learn.annotation.LogMeCustomAnnotationProcessor
pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>fun.n.learn</groupId>
<artifactId>javaCustomAnnotation</artifactId>
<version>0.1.0</version>
<build>
<plugins>
<plugin>
<!-- Configure the project to use java 8 version. -->
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.5.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
<!-- Disable annotation processing for ourselves. -->
<!-- <compilerArgument>-proc:none</compilerArgument> -->
</configuration>
</plugin>
</plugins>
</build>
</project>
Now when I run mvn -e clean install
I get the following problem
[ERROR] COMPILATION ERROR :
[INFO] -------------------------------------------------------------
[ERROR] Bad service configuration file, or exception thrown while constructing Processor object: javax.annotation.processing.Processor: Provider fun.n.learn.annotation.LogMeCustomAnnotationProcessor not found
[INFO] 1 error
I must be missing a simple trick here. Any help?
回答1:
The default maven lifecycle runs javac with javax.annotation.processing.Processor file as a part of classpath. This cause compiler to expect a compiled instance of annotation processors listed in the files. But LogMeCustomAnnotationProcessor
is not compiled at that moment so compiler raises "Bad service configuration file ..." error. See bug report.
To solve this issue maven compilation phase can be separated to compile annotation processor at the first place and then compile whole project.
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.5.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
<executions>
<execution>
<id>default-compile</id>
<configuration>
<compilerArgument>-proc:none</compilerArgument>
<includes>
<include>fun/n/learn/annotation/LogMeCustomAnnotationProcessor.java</include>
<!--include dependencies required for LogMeCustomAnnotationProcessor -->
</includes>
</configuration>
</execution>
<execution>
<id>compile-project</id>
<phase>compile</phase>
<goals>
<goal>compile</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
default-compile
execution compiles LogMeCustomAnnotationProcessor
with disabled annotation processing in order to have successful compilation.
compile-project
compiles whole project with annotaton processing.
回答2:
Follow the following steps to resolve this:
- Edit
nbproject/project.properties
file - Search for
javac.processorpath
, and change it to:
javac.processorpath=\
${javac.classpath}:\
${libs.eclipselink.classpath}
回答3:
Ok. Found the issue. Earlier my pom.xml had the proc:none
line commented out. Now that I have got it back in action it is compiling fine. I need to find out exactly what this line does, but the answer to my question is just put the proc:none
back in game. This is how the build section of my pom.xml looks now.
<build>
<plugins>
<plugin>
<!-- Configure the project to use java 8 version. -->
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.5.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
<!-- Disable annotation processing for ourselves. -->
<compilerArgument>-proc:none</compilerArgument>
</configuration>
</plugin>
</plugins>
</build>
回答4:
I've encountered this error, in particular
Bad service configuration file, or exception thrown while constructing Processor object: javax.annotation.processing.Processor: Provider com.iviz.schemarestriction.processor.SchemaRestrictionCompilationProcessor could not be instantiated
when migrating maven project from JDK 1.8 (1.8.0_201) to OpenJDK 11(11.0.2).
It was fixed by adding dependency on (2.3.1 was the latest stable version)
<dependency>
<groupId>javax.xml.bind</groupId>
<artifactId>jaxb-api</artifactId>
<version>2.3.1</version>
</dependency>
来源:https://stackoverflow.com/questions/36248959/bad-service-configuration-file-or-exception-thrown-while-constructing-processor