我们在Mojo gwt-maven-plugin 2.4产品中使用GWT来编译GWT代码。
但是我们观察到，当我们运行mvn install时，即使未对GWT代码进行任何代码更改，gwt maven插件也会运行排列。
在这个问题上奋斗了一段时间之后，我们能够使用2个maven项目通过简单的设置重现它：
第一个项目（MyGwtMavenSampleSource）：包含GWT代码以及gwt模块xml文件
第二个项目（MavenBuilderMod）：包含MyGwtMavenSampleSource作为maven依赖项，并将建立战争
文件。
以下是这两个项目的poms：
第一个项目：MyGwtMavenSampleSource
<?xml version="1.0" encoding="UTF-8"?>
<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/maven-v4_0_0.xsd">
<!-- POM file generated with GWT webAppCreator -->
<modelVersion>4.0.0</modelVersion>
<groupId>GWTMavenPlugin</groupId>
<artifactId>MyGwtMavenSampleSource</artifactId>
<packaging>jar</packaging>
<version>0.0.1-SNAPSHOT</version>
<name>GWT Maven Archetype</name>
<properties>
<!-- Convenience property to set the GWT version -->
<gwtVersion>2.4.0</gwtVersion>
<!-- GWT needs at least java 1.5 -->
<webappDirectory>${project.build.directory}/${project.build.finalName}</webappDirectory>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-servlet</artifactId>
<version>${gwtVersion}</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-user</artifactId>
<version>${gwtVersion}</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.7</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>javax.validation</groupId>
<artifactId>validation-api</artifactId>
<version>1.0.0.GA</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>javax.validation</groupId>
<artifactId>validation-api</artifactId>
<version>1.0.0.GA</version>
<classifier>sources</classifier>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.*</include>
</includes>
</resource>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.*</include>
</includes>
</resource>
</resources>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
第二个项目：MavenBuilderMod
<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>GWTMavenPlugin</groupId>
<artifactId>MavenBuilderMod</artifactId>
<packaging>war</packaging>
<version>0.0.1-SNAPSHOT</version>
<properties>
<!-- Convenience property to set the GWT version -->
<gwtVersion>2.4.0</gwtVersion>
<!-- GWT needs at least java 1.5 -->
<webappDirectory>${project.build.directory}/${project.build.finalName}</webappDirectory>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-servlet</artifactId>
<version>${gwtVersion}</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-user</artifactId>
<version>${gwtVersion}</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.7</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>javax.validation</groupId>
<artifactId>validation-api</artifactId>
<version>1.0.0.GA</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>javax.validation</groupId>
<artifactId>validation-api</artifactId>
<version>1.0.0.GA</version>
<classifier>sources</classifier>
<scope>test</scope>
</dependency>
<dependency>
<groupId>GWTMavenPlugin</groupId>
<artifactId>MyGwtMavenSampleSource</artifactId>
<version>0.0.1-SNAPSHOT</version>
<scope>compile</scope>
</dependency>
</dependencies>
<build>
<outputDirectory>${webappDirectory}/WEB-INF/classes</outputDirectory>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>2.8</version>
<executions>
<execution>
<id>src-dependencies</id>
<phase>package</phase>
<goals>
<goal>unpack-dependencies</goal>
</goals>
<configuration>
<classifier>sources</classifier>
<failOnMissingClassifierArtifact>false</failOnMissingClassifierArtifact>
<outputDirectory>${project.build.directory}/sources</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
<!-- GWT Maven Plugin -->
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>gwt-maven-plugin</artifactId>
<version>2.4.0</version>
<executions>
<execution>
<goals>
<goal>compile</goal>
</goals>
</execution>
</executions>
<!-- Plugin configuration. There are many available options, see
gwt-maven-plugin documentation at codehaus.org -->
<configuration>
<runTarget>MyGwtMavenSampleSource.html</runTarget>
<hostedWebapp>${webappDirectory}</hostedWebapp>
<modules>
<module>com.ca.gwt.maven.sample.MyGwtMavenSampleSource</module>
</modules>
</configuration>
</plugin>
<!-- Copy static web files before executing gwt:run -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<version>2.1.1</version>
<executions>
<execution>
<phase>compile</phase>
</execution>
</executions>
<configuration>
<webappDirectory>${webappDirectory}</webappDirectory>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.2</version>
<configuration>
<source>1.5</source>
<target>1.5</target>
</configuration>
</plugin>
</plugins>
</build>
</project>
因此，问题是，在这种设置中，我们如何才能使gwt-maven-plugin /编译器仅在代码更改时运行排列。
注意：如果将gwt模块xml文件放在包含gwt-maven-plugin的同一个maven模块中，这将按预期工作（即仅在更改代码时才运行排列）
最佳答案
根本问题是Maven对增量构建的支持中断，以及gwt-maven-plugin中可能对增量构建的支持中断（特别是如果您仍在使用2年以上的版本！）。
gwt-maven-plugin会以某种方式看到gwt.xml文件已更改（跟踪第一个模块的构建，理想情况下，如果未进行任何更改，它实际上应该是无操作的；重新复制资源和/或重建JAR会可能足以向下触发问题），尤其是它产生的nocache.js文件较新。
我认为更好的设置是在第一个模块中运行gwt-maven-plugin并将所有内容打包为ZIP或WAR，然后可以将其用作WAR叠加层。不幸的是，这会使运行DevMode更加困难，但是it's workable。