每当我更改源文件（GWT）时，将调用Maven Project Builder [英] Maven Project Builder is invoked every time I change a source file (GWT)
问题描述
我正在使用maven 2.2.1， gwt-maven plugin （2.4.0），Eclipse Indigo（3.7）和m2eclipse插件。
依赖关系和一般配置似乎很好，因为网络应用程序编译没有任何问题，也可以在生产模式下工作。
同样适用托管模式。
但是我有一个奇怪的行为：当我在Java / GWT源文件中更改单行时， Maven Project Builder 被调用并且这个步骤痛苦地（约10秒），并且eclipse有时在这段时间不可用。
这是m2eclipse的正常行为吗？
是否有任何方法加速？
注意：我不得不为m2eclipse配置生命周期插件。这是pom文件的重要部分：
< build>
<！ - 在用于开发模式的文件夹中生成编译的东西 - >
< outputDirectory> $ {webappDirectory} / WEB-INF / classes< / outputDirectory>
< plugins>
<！ - GWT Maven插件 - >
< plugin>
< groupId> org.codehaus.mojo< / groupId>
< artifactId> gwt-maven-plugin< / artifactId>
< version> 2.4.0< / version>
<执行>
< execution>
< goals>
< goal> compile< / goal>
< goal> test< / goal>
< / goals>
< / execution>
< / executions>
<！ - 插件配置。有很多可用选项，请参阅codehaus.org上的gwt-maven-plugin
文档 - >
< configuration>
< runTarget> index.html< / runTarget>
< hostedWebapp> $ {webappDirectory}< / hostedWebapp>
< i18nMessagesBundle> com.gmi.nordborglab.testapp.client.Messages< / i18nMessagesBundle>
< / configuration>
< / plugin>
<！ - 在执行gwt之前复制静态Web文件：run - >
< plugin>
< groupId> org.apache.maven.plugins< / groupId>
< artifactId> maven-war-plugin< / artifactId>
< version> 2.1.1< / version>
<执行>
< execution>
< phase> compile< / phase>
< goals>
< goal> expanding< / goal>
< / goals>
< / execution>
< / executions>
< configuration>
< webappDirectory> $ {webappDirectory}< / webappDirectory>
< / configuration>
< / plugin>
< / plugins>
< pluginManagement>
< plugins>
< plugin>
< groupId> org.eclipse.m2e< / groupId>
< artifactId>生命周期映射< / artifactId>
< version> 1.0.0< / version>
< configuration>
< lifecycleMappingMetadata>
< pluginExecutions>
< pluginExecution>
< pluginExecutionFilter>
< groupId> org.codehaus.mojo< / groupId>
< artifactId> gwt-maven-plugin< / artifactId>
< versionRange> [2.4.0，）< / versionRange>
< goals>
< goal> resources< / goal>
< goal> compile< / goal>
< / goals>
< / pluginExecutionFilter>
< action>
< execute />
< / action>
< / pluginExecution>
< pluginExecution>
< pluginExecutionFilter>
< groupId> org.apache.maven.plugins< / groupId>
< artifactId> maven-war-plugin< / artifactId>
< versionRange> [2.1.1，）< / versionRange>
< goals>
< goal> expanding< / goal>
< / goals>
< / pluginExecutionFilter>
< action>
< execute />
< / action>
< / pluginExecution>
< / pluginExecutions>
< / lifecycleMappingMetadata>
< / configuration>
< / plugin>
< / plugins>
< / pluginManagement>
< / build>
这完美地说明了为什么m2e不允许任何未知插件默认运行在增量版本上（ http://wiki.eclipse.org/M2E_plugin_execution_not_covered#Background ）。大多数maven插件不适合增量建筑，每当调用时都会进行完整的构建（作为奖励，您可能会遇到类加载器泄漏）。
在您的插件管理部分，你指定gwt：resources，gwt：compile和war：expanded应该执行。默认情况下，它们是在增量版本上执行的，这意味着每次更改资源。由于这些目标/插件未针对增量版本进行优化，因此需要一段时间才能完成。
如果要加快速度，可以告诉m2e执行他们只有在完整版本（即项目清理后）使用
< execute>
< runOnIncremental> false< / runOnIncremental>
< / execute>
然后，手动执行eclipse clean build会自动触发它们的执行。请注意，JDT有时会决定将增量版本推广到完整版本。
我相信（但可能是错误的），如果您使用Google Eclipse插件，您可以忽略gwt：resources和gwt：compile altogether（通过用< ignore>替换< execute>）。
Recently I converted my GWT web-app (GWT 2.4.0) to a maven project.
I am using maven 2.2.1, gwt-maven plugin (2.4.0), Eclipse Indigo (3.7) and the m2eclipse plugin.
The dependencies and general configuration seem to be fine as the web-app compiles without any problems and also works in production mode.
The same applies to hosted mode.
However I have a strange behavior: When I change a single line in a Java/GWT source file, the Maven Project Builder is invoked and this steps takes painfully long (around 10 secs) and eclipse sometimes becomes unusable during this time.
Is this a normal behavior of m2eclipse?
And if it is, is there any way to speed it up?
Note: I had to configure the life cycle plugin for m2eclipse. Here is the important section of the pom file:
<build>
<!-- Generate compiled stuff in the folder used for developing mode -->
<outputDirectory>${webappDirectory}/WEB-INF/classes</outputDirectory>
<plugins>
<!-- GWT Maven Plugin -->
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>gwt-maven-plugin</artifactId>
<version>2.4.0</version>
<executions>
<execution>
<goals>
<goal>compile</goal>
<goal>test</goal>
</goals>
</execution>
</executions>
<!-- Plugin configuration. There are many available options, see gwt-maven-plugin
documentation at codehaus.org -->
<configuration>
<runTarget>index.html</runTarget>
<hostedWebapp>${webappDirectory}</hostedWebapp>
<i18nMessagesBundle>com.gmi.nordborglab.testapp.client.Messages</i18nMessagesBundle>
</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>
<goals>
<goal>exploded</goal>
</goals>
</execution>
</executions>
<configuration>
<webappDirectory>${webappDirectory}</webappDirectory>
</configuration>
</plugin>
</plugins>
<pluginManagement>
<plugins>
<plugin>
<groupId>org.eclipse.m2e</groupId>
<artifactId>lifecycle-mapping</artifactId>
<version>1.0.0</version>
<configuration>
<lifecycleMappingMetadata>
<pluginExecutions>
<pluginExecution>
<pluginExecutionFilter>
<groupId>org.codehaus.mojo</groupId>
<artifactId>gwt-maven-plugin</artifactId>
<versionRange>[2.4.0,)</versionRange>
<goals>
<goal>resources</goal>
<goal>compile</goal>
</goals>
</pluginExecutionFilter>
<action>
<execute />
</action>
</pluginExecution>
<pluginExecution>
<pluginExecutionFilter>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<versionRange>[2.1.1,)</versionRange>
<goals>
<goal>exploded</goal>
</goals>
</pluginExecutionFilter>
<action>
<execute />
</action>
</pluginExecution>
</pluginExecutions>
</lifecycleMappingMetadata>
</configuration>
</plugin>
</plugins>
</pluginManagement>
</build>
This perfectly illustrates why m2e doesn't let any "unknown" plugins to run on incremental build by default ( http://wiki.eclipse.org/M2E_plugin_execution_not_covered#Background ). Most maven plugins aren't fit for incremental building and do a complete build whenever they're invoked (and as a bonus, you might get classloader leakages).
In your plugin management section, you specified that gwt:resources, gwt:compile and war:exploded should be executed. By default, they're executed on incremental builds, that means on EVERY resource change. Since these goals/plugins aren't optimized for an incremental build, they take a while to complete.
If you want to speed things up, you can tell m2e to execute them only on Full builds (i.e. after a project clean) by using
<execute>
<runOnIncremental>false</runOnIncremental>
</execute>
Then, manually doing an eclipse clean build will automatically trigger their execution. Be aware that JDT sometimes decides to promote incremental builds to full ones.
I believe (but may be wrong) that, if you were using the Google Eclipse Plugin, you could ignore gwt:resources and gwt:compile altogether (by replacing <execute> with <ignore>).
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