maven springboot怎么将jar包打包到指定目录

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如何将jar包打包到指定目录

1.目的

将不常用的比如spring,druid等不常用打包到lib目录，这样每次上线不需要上传这些。第三方或者常改动的还打包到本身的jar包内，每次上线都会新打包。

这样原来的100多M的jar包，可以变成2、3M。

如图所示：

原来的打包方式

改后的方式：

2.修改pom

简单解释一下，includes标签内就是打入jar包第三方jar。将上面的2M的包解压缩后，就是includes的包。

如图所示。

excludeGroupIds和excludeArtifactIds 是配置不在lib目录里的包，由于java启动加载的机制是优先加载jar包，
再加载外部目录，如果jar包都存在两个地方，这样配置就没有意义了，每次还是得重新发布lib目录，所以将includes
中的包，再在excludeGroupIds 和 excludeArtifactIds 配置上。

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
            <version>2.0.5.RELEASE</version>
            <executions>
                <execution>
                    <goals>
                        <goal>repackage</goal>
                        <goal>build-info</goal>
                    </goals>
                </execution>
            </executions>
            <configuration>
                <layout>ZIP</layout>
                <includes>
                    <include>
                        <groupId>nothing</groupId>
                        <artifactId>nothing</artifactId>
                    </include>
                    <include>
                        <groupId>com.etc</groupId>
                        <artifactId>etc-manage-api</artifactId>
                    </include>
                    <include>
                        <groupId>com.etc</groupId>
                        <artifactId>etc-manage-core</artifactId>
                    </include>
                    <include>
                        <groupId>com.etc</groupId>
                        <artifactId>etc-manage-rpc-api</artifactId>
                    </include>
                    <include>
                        <groupId>com.sinoiov.etc.apollo</groupId>
                        <artifactId>apollo-spring-boot-starter</artifactId>
                    </include>
                </includes>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-dependency-plugin</artifactId>
            <executions>
                <execution>
                    <id>copy</id>
                    <phase>package</phase>
                    <goals>
                        <goal>copy-dependencies</goal>
                    </goals>
                    <configuration>
                        <excludeGroupIds>
                            com.sinoiov.etc.apollo
                        </excludeGroupIds>
                        <excludeArtifactIds>
                            etc-manage-api,etc-manage-core,etc-manage-rpc-api
                        </excludeArtifactIds>
                        <outputDirectory>${project.build.directory}/lib</outputDirectory>
                    </configuration>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

3.修改启动脚本

原脚本

java -jar etc-manage-service-basic-2.2.0.jar

现脚本 (如果相对目录不好用，就用绝对目录试试)

java Dloader.path=../lib  -jar etc-manage-service-basic-2.2.0.jar

jar包外指定配置文件及原理

解决方案

修改maven的pom.xml文件

不拷贝资源文件

<resources>
    <resource>
        <directory>src/main/resources</directory>
        <excludes>
            <exclude>*</exclude>
        </excludes>
        <filtering>true</filtering>
    </resource>
</resources>

修改打包方式

<plugin>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-maven-plugin</artifactId>
    <configuration>
        <layout>ZIP</layout>
    </configuration>
</plugin>

运行

假设application.properties和application-{profile}.properties都在/tmp/temp/config，jar文件在/tmp/temp

java -Dloader.path=file:///tmp/temp/config,demo-1.0.jar -jar demo-1.0.jar

原理

对比jar包中MANIFEST.MF文件在`ZIP配置前后的区别

配置前：

Main-Class: org.springframework.boot.loader.JarLauncher
Start-Class: com.chinaunicom.gateway.GatewayApplication

配置后：

Main-Class: org.springframework.boot.loader.PropertiesLauncher
Start-Class: com.chinaunicom.gateway.GatewayApplication

发现是类加载器变了，查看org.springframework.boot.loader包下所有加载器实现：

查看五个类描述：官方文档

JarLauncher

Launcher for JAR based archives. This launcher assumes that dependency jars are included inside a /BOOT-INF/lib directory and that application classes are included inside a /BOOT-INF/classes directory.

WarLauncher

Launcher for WAR based archives. This launcher for standard WAR archives. Supports dependencies in WEB-INF/lib as well as WEB-INF/lib-provided, classes are loaded from WEB-INF/classes.

PropertiesLauncher

Launcher for archives with user-configured classpath and main class via a properties file. This model is often more flexible and more amenable to creating well-behaved OS-level services than a model based on executable jars.
Looks in various places for a properties file to extract loader settings, defaulting to application.properties either on the current classpath or in the current working directory. The name of the properties file can be changed by setting a System property loader.config.name (e.g. -Dloader.config.name=foo will look for foo.properties. If that file doesn't exist then tries loader.config.location (with allowed prefixes classpath: and file: or any valid URL). Once that file is located turns it into Properties and extracts optional values (which can also be provided overridden as System properties in case the file doesn't exist):
loader.path: a comma-separated list of directories (containing file resources and/or nested archives in .jar or .zip or archives) or archives to append to the classpath. BOOT-INF/classes,BOOT-INF/lib in the application archive are always used
loader.main: the main method to delegate execution to once the class loader is set up. No default, but will fall back to looking for a Start-Class in a MANIFEST.MF, if there is one in ${loader.home}/META-INF.

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