GWT编译器不支持java.io.ObjectOutputStream类
你必须参考https://developers.google.com/web-toolkit/doc/latest/RefJreEmulation#Package_java_io在使用Java类之前，请确保GWT支持它。
我按照本教程创建我的ant构建文件，java编译该文件，而GWT编译该文件并执行正确的操作来构建我的.war文件。
我使用Eclipse和GWT编译工作，当我运行开发模式时，它工作。我还成功地部署在tomcat上。
问题是，当我运行脚本时，编译工作正常，但它在gwt编译器任务中失败了。我的ant构建脚本如下：
<project name="vlp" default="gwt.compile" basedir=".">
<tstamp />
<!-- ################# PROPERTIES ################ -->
<!-- directory properties -->
<!-- source -->
<property name="projectName" value="VirtualLabPortal" />
<property name="src.dir" location="src" />
<property name="build.dir" location="bin" />
<property name="src.build.dir" location="${build.dir}/src" />
<property name="gwt.build.dir" location="${build.dir}/gwt" />
<property name="gwt.unitCache.dir" location="gwt-unitCache" />
<!-- libraries -->
<property name="src.lib.dir" location="war/WEB-INF/lib" />
<!-- ___________________________________________________________________
| |
| Configure path source/test |
|___________________________________________________________________|
-->
<path id="compile.path">
<fileset dir="${src.lib.dir}" includes="*.jar" />
<fileset dir="${src.lib.dir}/gwt" includes="*.jar" />
</path>
<!-- ___________________________________________________________________
| |
| Clean old compiled source/test/war |
|___________________________________________________________________|
-->
<target name="clean" description="Clean all the old build files.">
<delete dir="${build.dir}" />
<delete dir="${gwt.unitCache.dir}" />
<delete file="${projectWar}" />
<delete file="${src.lib.dir}/${projectJar}" />
</target>
<!-- ___________________________________________________________________
| |
| Compile the source |
|(should exclude gwtview code which is compiled by the gwt compiler)|
|___________________________________________________________________|
-->
<target name="src.compile" depends="clean" description="Compile the source code when everything has been cleaned.">
<mkdir dir="${src.build.dir}" />
<javac encoding="utf-8" destdir="${src.build.dir}" nowarn="true">
<src path="${src.dir}" />
<classpath refid="compile.path" />
</javac>
</target>
<!-- ___________________________________________________________________
| |
| Invoke the GWT compiler |
|___________________________________________________________________|
-->
<property name="module.gwt.xml" location="${src.dir}/com/banctecmtl/ca/vlp" />
<target name="gwt.compile" depends="src.compile">
<java failonerror="true" fork="true" classname="com.google.gwt.dev.Compiler">
<classpath>
<!-- src dir is added to ensure the module.xml file(s) are on the classpath -->
<pathelement location="${module.gwt.xml}" />
<path refid="compile.path" />
</classpath>
<jvmarg value="-Xmx512m" />
<arg line="${projectName} -logLevel ALL -style OBF -war ${build.dir}" />
</java>
</target>
<!-- ___________________________________________________________________
| |
| Copy the config files in the war directory |
|___________________________________________________________________|
-->
<property name="config.dir" location="war/config" />
<target name="copy-resources">
<copy todir="war/config" preservelastmodified="true">
<fileset dir="${config.dir}">
<include name="**.*" />
</fileset>
</copy>
</target>
<!-- ___________________________________________________________________
| |
| Create a Jar to be included in the war |
|___________________________________________________________________|
-->
<property name="projectJar" value="${projectName}.jar" />
<property name="gwt.client.dir" location="com/banctecmtl/ca/vlp/view/webview" />
<target name="jar" depends="src.compile">
<!-- should also depend on gwt.compile -->
<jar jarfile="${src.lib.dir}/${projectJar}" basedir="${src.build.dir}/">
<!-- Don't wrap any of the client only code into the JAR
<exclude name="${gwt.client.dir}/**/*.class"/> -->
<exclude name="${gwt.client.dir}/**/*.class" />
</jar>
</target>
<!-- ___________________________________________________________________
| |
| Create a War from the source |
|___________________________________________________________________|
-->
<property name="projectWar" value="${projectName}.war" />
<target name="war" depends="jar,copy-resources">
<war basedir="war" destfile="${projectWar}" webxml="war/WEB-INF/web.xml">
<exclude name="WEB-INF/**" />
<webinf dir="war/WEB-INF/">
<include name="lib/*.jar" />
<include name="classes/*.properties" />
<exclude name="**/gwt-dev.jar" />
<exclude name="**/gwt-user.jar" />
</webinf>
</war>
</target>
<!-- ___________________________________________________________________
| |
| Deploy to the production server |
|___________________________________________________________________|
-->
<!-- It is possible you can't run this from eclipse,
you need to edit the run configurations and add the
latest jsch library to the classpath -->
<property name="user" value="root" />
<property name="password" value="Banctec01" />
<property name="prodHost" value="vlp" />
<property name="dest" value="/usr/share/tomcat6/webapps/ROOT.war" />
<target name="deploy" depends="war">
<echo message="Copying to : ${user}@${prodHost}:${dest}" />
<scp file="${projectWar}" remoteTofile="${user}@${prodHost}:${dest}" password="${password}" trust="true" />
</target>
</project>
它失败，并出现以下错误：
Buildfile: D:workspacevlpbuild.xml
clean:
[delete] Deleting directory D:workspacevlpwarWEB-INFclasses
src.compile:
[mkdir] Created dir: D:workspacevlpwarWEB-INFclasses
[javac] D:workspacevlpbuild.xml:42: warning: 'includeantruntime' was not set, defaulting to build.sysclasspath=last; set to false for repeatable builds
[javac] Compiling 134 source files to D:workspacevlpwarWEB-INFclasses
[javac] Note: D:workspacevlpsrccombanctecmtlcavlpcontrollerscheduleScheduledTaskManager.java uses unchecked or unsafe operations.
[javac] Note: Recompile with -Xlint:unchecked for details.
gwt.compile:
[java] Checking for updates
[java] First launch was 134c3e23387
[java] Last ping was Mon Apr 23 14:42:48 EDT 2012, min wait is 86400000ms
[java] Module location: file:/D:/workspace/vlp/src/com/banctecmtl/ca/vlp/VirtualLabPortal.gwt.xml
[java] Loading inherited module 'com.google.gwt.user.User'
[java] Module location: jar:file:/D:/workspace/vlp/war/WEB-INF/lib/gwt/gwt-user.jar!/com/google/gwt/user/User.gwt.xml
[java] Loading inherited module 'com.google.gwt.animation.Animation'
[java] Module location: jar:file:/D:/workspace/vlp/war/WEB-INF/lib/gwt/gwt-user.jar!/com/google/gwt/animation/Animation.gwt.xml
[java] Loading inherited module 'com.google.gwt.core.Core'
[java] Module location: jar:file:/D:/workspace/vlp/war/WEB-INF/lib/gwt/gwt-user.jar!/com/google/gwt/core/Core.gwt.xml
[java] Loading inherited module 'com.google.gwt.dev.jjs.intrinsic.Intrinsic'
[java] Module location: jar:file:/D:/workspace/vlp/war/WEB-INF/lib/gwt/gwt-dev.jar!/com/google/gwt/dev/jjs/intrinsic/Intrinsic.gwt.xml
[java] Loading inherited module 'com.google.gwt.lang.LongLib'
[java] Module location: jar:file:/D:/workspace/vlp/war/WEB-INF/lib/gwt/gwt-dev.jar!/com/google/gwt/lang/LongLib.gwt.xml
[java] Loading inherited module 'com.google.gwt.emul.Emulation'
[java] Module location: jar:file:/D:/workspace/vlp/war/WEB-INF/lib/gwt/gwt-user.jar!/com/google/gwt/emul/Emulation.gwt.xml
[java] Loading inherited module 'com.google.gwt.logging.LogImpl'
[java] Module location: jar:file:/D:/workspace/vlp/war/WEB-INF/lib/gwt/gwt-user.jar!/com/google/gwt/logging/LogImpl.gwt.xml
[java] Loading inherited module 'com.google.gwt.xhr.XMLHttpRequest'
[java] Module location: jar:file:/D:/workspace/vlp/war/WEB-INF/lib/gwt/gwt-user.jar!/com/google/gwt/xhr/XMLHttpRequest.gwt.xml
[java] Loading inherited module 'com.google.gwt.core.Core'
[java] Module 'com.google.gwt.core.Core' has already been loaded and will be skipped
[java] Loading inherited module 'com.google.gwt.core.CompilerParameters'
[java] Module location: jar:file:/D:/workspace/vlp/war/WEB-INF/lib/gwt/gwt-user.jar!/com/google/gwt/core/CompilerParameters.gwt.xml
[java] [...]
[java] Loading inherited module 'com.google.gwt.user.User'
[java] Module 'com.google.gwt.user.User' has already been loaded and will be skipped
[java] Public resources found in...
[java] Translatable source found in...
[java] Persistent unit cache dir set to: D:workspacevlpwar..gwt-unitCache
[java] Compiling module VirtualLabPortal
[java] Looking for previously cached Compilation Units in D:workspacevlpwar..gwt-unitCache
[java] Loaded 0 units from persistent store.
[java] Starting UnitWriteThread.
[java] Found 0 cached units. Used 0 / 2413 units from cache.
[java] [ERROR] Unexpected internal compiler error
[java] java.lang.RuntimeException: Exception processing units
[java] at com.google.gwt.dev.javac.CompilationStateBuilder$CompileMoreLater.compile(CompilationStateBuilder.java:248)
[java] at com.google.gwt.dev.javac.CompilationStateBuilder.doBuildFrom(CompilationStateBuilder.java:447)
[java] at com.google.gwt.dev.javac.CompilationStateBuilder.buildFrom(CompilationStateBuilder.java:370)
[java] at com.google.gwt.dev.cfg.ModuleDef.getCompilationState(ModuleDef.java:360)
[java] at com.google.gwt.dev.Precompile.precompile(Precompile.java:252)
[java] at com.google.gwt.dev.Precompile.precompile(Precompile.java:233)
[java] at com.google.gwt.dev.Precompile.precompile(Precompile.java:145)
[java] at com.google.gwt.dev.Compiler.run(Compiler.java:232)
[java] at com.google.gwt.dev.Compiler.run(Compiler.java:198)
[java] at com.google.gwt.dev.Compiler$1.run(Compiler.java:170)
[java] at com.google.gwt.dev.CompileTaskRunner.doRun(CompileTaskRunner.java:88)
[java] at com.google.gwt.dev.CompileTaskRunner.runWithAppropriateLogger(CompileTaskRunner.java:82)
[java] at com.google.gwt.dev.Compiler.main(Compiler.java:177)
[java] Caused by: java.lang.NoSuchMethodError: com.google.gwt.dev.jjs.ast.JProgram.serializeTypes(Ljava/util/List;Ljava/io/ObjectOutputStream;)V
[java] at com.google.gwt.dev.javac.CompilationUnitImpl.<init>(CompilationUnitImpl.java:68)
[java] at com.google.gwt.dev.javac.SourceFileCompilationUnit.<init>(SourceFileCompilationUnit.java:48)
[java] at com.google.gwt.dev.javac.CompilationUnitBuilder$ResourceCompilationUnitBuilder.makeUnit(CompilationUnitBuilder.java:154)
[java] at com.google.gwt.dev.javac.CompilationUnitBuilder.build(CompilationUnitBuilder.java:266)
[java] at com.google.gwt.dev.javac.CompilationStateBuilder$CompileMoreLater$1.run(CompilationStateBuilder.java:223)
BUILD FAILED
D:workspacevlpbuild.xml:60: Java returned: 1
Total time: 36 seconds
我发现将gwt编译器类名更改为DevMode是成功构建的。使用：classname="com.google.gwt.dev.DevMode"而不是classname="com.google.gwt.dev.Compiler"。
编辑：我重构了上面的XML。build.xml会清理所有bin目录。我还将javac指向bin/src目录，Google Web Toolkit编译器输出指向：bin/gwt。编译器仍然无法工作。。。
编辑：我立即从谷歌开发者网站下载了最新的SDK，并覆盖了我的类路径和eclipse插件中的旧库。仍然无法使用ant构建脚本。
有人看到这里可能出了什么问题吗？
我只能说，方法com.google.gwt.dev.jjs.ast.JProgram.serializeTypes(Ljava/util/List;Ljava/io/ObjectOutputStream;)V仅在gwt dev 2.4.0中引入。它在gwt dev 2.3.0中不存在。
这意味着类路径中有两个gwt-dev版本。其中之一是2.4.0，这就是com.google.gwt.dev.javac.CompilationUnitImpl正在寻找该方法的原因。另一个是2.3.0或更旧版本，这就是为什么找不到该方法（JProgram类是由编译器使用旧版本加载的）。
试着彻底查一下。或者试着开始一个新的环境，在这个环境中你可以很好地关注正在发生的事情。
tl；dr：这是由于在类上下文不足或不正确的情况下，Compiler和DevMode提供的链接器存在差异
追踪问题
我注意到您的repo存在于当前GWT主干中。具体来说，它在这个代码块中失败了：
ArrayList<CompilationUnit> resultUnits = new ArrayList<CompilationUnit>();
do {
// Compile anything that needs to be compiled.
buildQueue = new LinkedBlockingQueue<CompilationUnitBuilder>();
final ArrayList<CompilationUnit> newlyBuiltUnits = new ArrayList<CompilationUnit>();
final CompilationUnitBuilder sentinel = CompilationUnitBuilder.create((GeneratedUnit) null);
final Throwable[] workerException = new Throwable[1];
Thread buildThread = new Thread() {
@Override
public void run() {
try {
do {
CompilationUnitBuilder builder = buildQueue.take();
if (builder == sentinel) {
return;
}
// Expensive, must serialize GWT AST types to bytes.
CompilationUnit unit = builder.build(); // <-- Right here.
newlyBuiltUnits.add(unit);
} while (true);
} catch (Throwable e) {
workerException[0] = e;
}
}
};
将堆栈展开到比您的跟踪更远的位置，我们浏览了一个工厂和十层代码，直到我们最终到达UnifyAst.java
...
mapApi(enclosingType);
// Now the method should be there.
method = methodMap.get(sig);
if (method == null) {
// TODO: error logging
throw new NoSuchMethodError(sig);
}
assert !method.isExternal();
return method;
...
这是GWT的预编译阶段调用的NoSuchMethodError的唯一实例。
编译器和DevMode链接的差异
酷。既然我们已经深入研究了为什么它会爆炸，让我们弄清楚为什么DevMode能工作，而Compiler却不能。我们注意到，两者都导入了Util.java的同一副本，因此技术上，这两种类型对我们的java编译器（只是不是GWT编译器）都是静态可用的。
检查连接体，我们注意到Compiler直接使用Link.link：
Link.link(logger.branch(TreeLogger.TRACE, logMessage), module,
generatedArtifacts, allPerms, resultFiles, options.getWarDir(),
options.getDeployDir(), options.getExtraDir(), precompileOptions);
而DevMode使用了一个简洁得多的静态调用，在StandardLinkerContext:的一个实例中填充了一个单独的过程
link(loadLogger, module);
...
@Override
protected synchronized void produceOutput(TreeLogger logger, StandardLinkerContext linkerStack,
ArtifactSet artifacts, ModuleDef module, boolean isRelink) throws UnableToCompleteException {
...
linkerStack.produceOutput(linkLogger, artifacts, Visibility.Public, outFileSet);
linkerStack.produceOutput(linkLogger, artifacts, Visibility.Deploy, deployFileSet);
linkerStack.produceOutput(linkLogger, artifacts, Visibility.Private, extraFileSet);
...
}
太棒了！那么，我该如何修复它呢
正如在撰写本文的过程中所接受的那样，yair为这个问题提供了一个这样的诊断，指出在两个版本的GWT的上下文中，预编译步骤对于冲突的类标识是不健壮的。precompilation.getGeneratedArtifacts();引入错误或不充分对象的其他类可见性问题也可能导致此repo。
我认为这个问题现在已经解决了，因为yair被给予了接受回答的状态。但对于其他浏览过这篇文章的人来说，其他类路径或可见性问题可能会导致这个问题再次出现。
你必须参考https://developers.google.com/web-toolkit/doc/latest/RefJreEmulation#Package_java_io在使用Java类之前，请确保GWT支持它。
您派生一个JVM来运行Gwt编译器，bin目录位于ClassPath中。
当Eclipse在开发模式下编译时，bin中的剩余类可能会阻止编译器正确处理一些源文件。
在调用Ant目标之前，应该确保bin目录为空。那时可能会过去。
我建议您使用两个目标目录：一个用于从Java源代码编译的类，另一个用于GWT生成的文件。然后，目标war将两者收集到WAR中。