一、问题描述：
部署一个maven打包项目时，jar包，依赖lib包全部手动上传至服务器，然后用maven部署报错：Exception in thread "main" java.lang.NoClassDefFoundError:，当时心想可能是依赖的lib包有问题，各种重新部署（以为是依赖的包没有更新），确忽略了一个大问题：pom.xml没仔细检查。解决方法：最终发现<plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-jar-plugin</artifactId> <version>2.4</version> <configuration> <archive> <manifest> <addClasspath>true</addClasspath> <classpathPrefix>lib/</classpathPrefix> <mainClass>com.bj58.finance.EntryMain</mainClass> </manifest> </archive> </configuration> </plugin>，这一段被注释了......直接导致依赖的jar包完全没有被添加进MANIFEST.MF（jar包解压缩后：jar包名/META-INF/MANIFEST.MF）的Class-Path。所以最终运行代码时，只要是依赖别的jar包的类就会报错，找不到类。这里涉及到MANIFEST.MF相关，详情请看传送门。
二、这里就涉及Maven常用插件pom.xml中的配置了。特此收集常用配置如下：
1.根据项目类型打包：jar/war打包插件。
首先看<packaging>jar</packing>属性,主流就2种类型。
打成jar包插件:
<plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-jar-plugin</artifactId> <version>2.4</version> <configuration> <archive> <manifest> <addClasspath>true</addClasspath> <classpathPrefix>lib/</classpathPrefix> <mainClass>com.*.MainClass</mainClass> </manifest> </archive> </configuration></plugin>
打成war包插件:
<plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-war-plugin</artifactId> <version>2.1.1</version> <configuration> <webResources> <resource> <directory>src/main/webapp</directory> <excludes> <exclude>**/*.jpg</exclude> </excludes> </resource> </webResources> </configuration> </plugin>
2. 编译插件
全局属性:源码编码为utf-8
<properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> </properties>
<plugin> <artifactId>maven-compiler-plugin</artifactId> <version>2.3.2</version> <configuration> <source>1.6</source>//源代码编译版本 <target>1.6</target>//目标平台编译版本 <includes> <include>**/*.java</include> </includes>
<encoding>${project.build.sourceEncoding}</encoding>//字符集编码,这里引用全局属性 </configuration></plugin>
3.拷贝依赖jar包至target/lib下
<plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-dependency-plugin</artifactId> <version>2.6</version> <executions> <execution> <id>copy-dependencies</id> <phase>compile</phase> <goals> <goal>copy-dependencies</goal> </goals> <configuration> <!-- [Math Processing Error]project.build.directory为Maven内置变量，缺省为target−−><outputDirectory>{project.build.directory}/lib</outputDirectory> <!-- 表示是否不包含间接依赖的包 --> <excludeTransitive>false</excludeTransitive> <!-- 表示复制的jar文件去掉版本信息 --> <stripVersion>false</stripVersion> </configuration> </execution> </executions> </plugin>
4.描述打包插件
它支持各种打包文件格式，包括zip、tar.gz、tar.bz2等等
执行mvn assembly:assembly, 执行成功后会在target文件夹下多出一个以-jar-with-dependencies结尾的JAR包. 这个JAR包就包含了项目所依赖的所有JAR的CLASS.
<plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-assembly-plugin</artifactId> <version>2.2.1</version> <configuration> <descriptors> <descriptor>src/main/assembly/assembly.xml</descriptor> </descriptors>
<descriptorRefs> <descriptorRef>jar-with-dependencies</descriptorRef>//把依赖的jar包一起打包 </descriptorRefs> </configuration> <executions> <execution> <id>make-assembly</id> <phase>package</phase> <goals> <goal>single</goal> </goals> </execution> </executions></plugin>
5.maven跳过测试用例插件
maven-surefire-plugin 是maven里执行测试用例的插件，不显示配置就会用默认配置。这个插件的 surefire:test 命令会默认绑定maven执行的 test 阶段。
<plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-surefire-plugin</artifactId> <version>2.19</version> <dependencies> <dependency> <groupId>org.apache.maven.surefire</groupId> <artifactId>surefire-junit47</artifactId> <version>2.19</version> </dependency> </dependencies> <configuration> <skipTests>true</skipTests>//跳过测试用例 </configuration></plugin>
6.maven自动build插件
<pluginManagement> <plugins> <plugin> <groupId>org.eclipse.m2e</groupId> <artifactId>lifecycle-mapping</artifactId> <version>1.0.0</version> <configuration> <lifecycleMappingMetadata> <pluginExecutions> <pluginExecution> <pluginExecutionFilter> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-dependency-plugin</artifactId> <versionRange>[2.0,)</versionRange> <goals> <goal>copy-dependencies</goal> </goals> </pluginExecutionFilter> <action> <ignore/> </action> </pluginExecution> <pluginExecution> <pluginExecutionFilter> <groupId>org.codehaus.mojo</groupId> <artifactId>aspectj-maven-plugin</artifactId> <versionRange>[1.0,)</versionRange> <goals> <goal>test-compile</goal> <goal>compile</goal> </goals> </pluginExecutionFilter> <action> <ignore/> </action> </pluginExecution> </pluginExecutions> </lifecycleMappingMetadata> </configuration> </plugin> </plugins></pluginManagement>
