内容简介:Maven问题解决记录:1、远程仓库中有jar,但是编译时找不到。问题描述:
Maven问题解决记录:
1、远程仓库中有jar,但是编译时找不到。
问题描述:
Failed to execute goal on project amps-dcm: Could not resolve dependencies for project com.zollty.pss:amps-dcm:war:0.0.1-SNAPSHOT: The following artifacts could not be resolved: org.zollty.util:zollty-util:jar:1.0, org.zollty.log:zollty-log:jar:1.0: Failure to find org.zollty.util:zollty-util:jar:1.0 in http://172.27.18.106:8081/nexus/content/groups/public was cached in the local repository, resolution will not be reattempted until the update interval of LocalMirrorId has elapsed or updates are forced -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR]
解决方案:
打开本地仓库目录,找到那个jar的位置,把残留的文件夹全都删除。然后再重新下载这个jar。
还是不行?有可能是parent项目中也存在xxx.lastUpdate的文件。所以把parent项目也清理一下。
例如:
<parent>
<groupId>org.zollty</groupId>
<artifactId>zollty-org</artifactId>
<version>1.0</version>
</parent>
那么,请检查
D:\C\Java\maven3\repo\org\zollty\zollty-org\1.0目录!!
2、transitive dependencies (if any) will not be available, enable debug logging for more details
详细错误如下:
[WARNING] The POM for org.zollty.util:zollty-util:jar:1.0 is invalid, transitive dependencies (if any) will not be available, enable debug logging for more details
解决方法: 显式引入:zollty-util:jar:1.0依赖的jar即可。
3、如何将Maven依赖的jar发布到tomcat的WEB-INF/lib下面
在.classpath文件中设置:
<classpathentry kind="con" path="org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER">
<attributes>
<attribute name="maven.pomderived" value="true"/>
<attribute name="org.eclipse.jst.component.dependency" value="/WEB-INF/lib"/>
</attributes>
</classpathentry>
注意,有些插件是:<classpathentry kind="con" path="org.maven.ide.eclipse.MAVEN2_CLASSPATH_CONTAINER">
4、配置了拷贝(overlays)引入的war包的Eclipse-Maven 项目,当发布到服务器上时,没有拷贝到war中的文件到发布的服务器上。
pom配置如下:
<plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-war-plugin</artifactId> <version>2.1.1</version> <configuration> <attachClasses>true</attachClasses> <overlays> <overlay> <groupId>com.zollty.pss</groupId> <artifactId>abframe</artifactId> </overlay> <overlay> <!-- don't remove this tag. empty groupId/artifactId represents the current build --> </overlay> </overlays> </configuration> </plugin>
原因: 没有配置支持overlays的Eclipse插件,即m2e-wtp插件。
有些Eclipse插件是这样
.project文件
<natures>
...
<nature>org.maven.ide.eclipse.maven2Nature</nature>
...
</natrues>
.classpath 文件
<classpathentry kind="con" path="org.maven.ide.eclipse.MAVEN2_CLASSPATH_CONTAINER">
<attributes>
<attribute name="maven.pomderived" value="true"/>
<attribute name="org.eclipse.jst.component.dependency" value="/WEB-INF/lib"/>
</attributes>
</classpathentry>
但是有些Eclipse插件是这样
.project文件
<natures>
...
<nature>org.eclipse.m2e.core.maven2Nature</nature>
...
</natures>
.classpath 文件
<classpathentry kind="con" path="org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER">
<attributes>
<attribute name="maven.pomderived" value="true"/>
<attribute name="org.eclipse.jst.component.dependency" value="/WEB-INF/lib"/>
</attributes>
</classpathentry>
经测试,第二个配置可以正确使用maven的war包依赖自动发布的功能。
如果是第一个配置,那需要安装m2e-wtp插件。
安装后,完整的配置如下
.project文件
<?
xml
version
=
"1.0"
encoding
=
"UTF-8"
?>
<
projectDescription
>
<
name
>amps-dcm</
name
>
<
comment
></
comment
>
<
projects
>
</
projects
>
<
buildSpec
>
<
buildCommand
>
<
name
>org.eclipse.wst.jsdt.core.javascriptValidator</
name
>
<
arguments
>
</
arguments
>
</
buildCommand
>
<
buildCommand
>
<
name
>org.eclipse.wst.common.project.facet.core.builder</
name
>
<
arguments
>
</
arguments
>
</
buildCommand
>
<
buildCommand
>
<
name
>com.genuitec.eclipse.j2eedt.core.WebClasspathBuilder</
name
>
<
arguments
>
</
arguments
>
</
buildCommand
>
<
buildCommand
>
<
name
>org.eclipse.jdt.core.javabuilder</
name
>
<
arguments
>
</
arguments
>
</
buildCommand
>
<
buildCommand
>
<
name
>com.genuitec.eclipse.j2eedt.core.J2EEProjectValidator</
name
>
<
arguments
>
</
arguments
>
</
buildCommand
>
<
buildCommand
>
<
name
>com.genuitec.eclipse.j2eedt.core.DeploymentDescriptorValidator</
name
>
<
arguments
>
</
arguments
>
</
buildCommand
>
<
buildCommand
>
<
name
>org.eclipse.wst.validation.validationbuilder</
name
>
<
arguments
>
</
arguments
>
</
buildCommand
>
<
buildCommand
>
<
name
>com.genuitec.eclipse.ast.deploy.core.DeploymentBuilder</
name
>
<
arguments
>
</
arguments
>
</
buildCommand
>
<
buildCommand
>
<
name
>org.eclipse.m2e.core.maven2Builder</
name
>
<
arguments
>
</
arguments
>
</
buildCommand
>
</
buildSpec
>
<
natures
>
<
nature
>org.eclipse.m2e.core.maven2Nature</
nature
>
<
nature
>org.eclipse.jem.workbench.JavaEMFNature</
nature
>
<
nature
>org.eclipse.wst.common.modulecore.ModuleCoreNature</
nature
>
<
nature
>com.genuitec.eclipse.ast.deploy.core.deploymentnature</
nature
>
<
nature
>com.genuitec.eclipse.j2eedt.core.webnature</
nature
>
<
nature
>org.eclipse.jdt.core.javanature</
nature
>
<
nature
>org.eclipse.wst.common.project.facet.core.nature</
nature
>
<
nature
>org.eclipse.wst.jsdt.core.jsNature</
nature
>
</
natures
>
</
projectDescription
>
.classpath 文件
<?
xml
version
=
"1.0"
encoding
=
"UTF-8"
?>
<
classpath
>
<
classpathentry
kind
=
"src"
output
=
"target/classes"
path
=
"src/main/java"
>
<
attributes
>
<
attribute
name
=
"optional"
value
=
"true"
/>
<
attribute
name
=
"maven.pomderived"
value
=
"true"
/>
</
attributes
>
</
classpathentry
>
<
classpathentry
excluding
=
"**"
kind
=
"src"
output
=
"target/classes"
path
=
"src/main/resources"
>
<
attributes
>
<
attribute
name
=
"maven.pomderived"
value
=
"true"
/>
</
attributes
>
</
classpathentry
>
<
classpathentry
kind
=
"src"
output
=
"target/test-classes"
path
=
"src/test/java"
>
<
attributes
>
<
attribute
name
=
"optional"
value
=
"true"
/>
<
attribute
name
=
"maven.pomderived"
value
=
"true"
/>
</
attributes
>
</
classpathentry
>
<
classpathentry
excluding
=
"**"
kind
=
"src"
output
=
"target/test-classes"
path
=
"src/test/resources"
>
<
attributes
>
<
attribute
name
=
"maven.pomderived"
value
=
"true"
/>
</
attributes
>
</
classpathentry
>
<
classpathentry
kind
=
"con"
path
=
"org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.6"
>
<
attributes
>
<
attribute
name
=
"maven.pomderived"
value
=
"true"
/>
</
attributes
>
</
classpathentry
>
<
classpathentry
kind
=
"con"
path
=
"org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER"
>
<
attributes
>
<
attribute
name
=
"maven.pomderived"
value
=
"true"
/>
<
attribute
name
=
"org.eclipse.jst.component.dependency"
value
=
"/WEB-INF/lib"
/>
</
attributes
>
</
classpathentry
>
<
classpathentry
kind
=
"output"
path
=
"target/classes"
/>
</
classpath
>
5、maven 无法确定 <T>T 的类型参数;对于上限为 long,java.lang.Object 的类型变量 T
无法确定 <X>X 的类型参数;对于上限为 X,java.lang.Object 的类型变量 X,不存在唯一最大实例
原因是,默认编译器(javac)的问题。解决方案:使用其他编译器,比如eclipse所用的编译器(JDT compiler from eclipse)。
在pom.xml中配置如下:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>${java-version}</source>
<target>${java-version}</target>
<compilerId>eclipse</compilerId>
</configuration>
<dependencies>
<dependency>
<groupId>org.codehaus.plexus</groupId>
<artifactId>plexus-compiler-eclipse</artifactId>
<version>2.3</version>
</dependency>
</dependencies>
</plugin>
参见:
http://www.eclipse.org/forums/index.php/t/1229/
6、使用JDT compiler时出现 枚举类型switch报错 问题:
Cannot switch on a value of type. Only convertible int values or enum variables are permitted
例如:
class
Foo {
static
enum
MyEnum { A }
void
foo() {
switch
( MyEnum.A ) {
case
A: } }
}
分析和解决方法:
Turns out that the setting org.eclipse.jdt.core.compiler.compliance
needs to be set to the target version in order for it to be able to recognize java.lang.Enum
.
This setting is only set by plexus-compiler-eclipse when both targetVersion
AND optimize
is set. [1]
Modify your pom like this and it should work:
<
plugins
>
<
plugin
>
<
groupId
>org.apache.maven.plugins</
groupId
>
<
artifactId
>maven-compiler-plugin</
artifactId
>
<
version
>3.1</
version
>
<!-- or 3.0 -->
<
configuration
>
<
compilerId
>eclipse</
compilerId
>
<
source
>1.6</
source
>
<
target
>1.6</
target
> <
optimize
>true</
optimize
>
<!-- add this line! -->
I'm not sure why it was decided in plexus-compiler-eclipse that optimization would affect the compliance level, so this is in fact a workaround.
see:
7、Maven报错:'version' contains an expression but should be a constant.
是因为 父pom还没有发布到仓库中,建议在仓库中检查一下父pom是否正确。
8、Maven WTP无法引用工程中的项目模块(org.eclipse.wst.common.component)
也就是说,在org.eclipse.wst.common.component文件中缺少如下的语句:
<dependent-module archiveName="tre-client-2.0.2-SNAPSHOT.jar" deploy-path="/WEB-INF/lib" handle="module:/resource/tre-client/tre-client">
<dependency-type>uses</dependency-type>
</dependent-module>
那是因为 被引用的项目的pom配置有问题,经我检查,问题出在如下一行
<resources>
<resource>
<directory>${basedir}/src/main/resources</directory>
</resource>
<resource>
<directory>${basedir}/src/main/java/com/zollty/report/client</directory>
<includes>
<include>*.xsd</include>
</includes>
<targetPath>${project.build.directory}/classes/com/zollty/report/client</targetPath>
</resource>
</resources>
但是,在这个目录下面,找不到任何 .xsd 文件,运行maven指令的时候不会报错,但是在这个WTP中就检测到了这个问题,所以没有生成这个引用。
9、报错:No compiler is provided in this environment. Perhaps you are running on a JRE rather than a JDK?
原因:JRE环境指定的是JRE目录,而不是JDK目录。
解决方法:
● Click on Windows -> Preferences -> Java -> Installed JREs -> Add -> Standard VM and Select JAVA_HOME.
● Select New JRE from Installed JREs and Press OK
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