简介
在之前spring boot3文章中咱们介绍了，spring boot3的一个重要个性就是反对把spring boot3的利用编译成为GraalVM的Native Image。
明天咱们用具体的例子来给大家演示一下如何正确的将spring boot3的利用编译成为native image。
装置GraalVM
如果要把spring boot3的app编译成为native利用，须要GraalVM的反对。
什么是GraalVM呢？
从名字就可以看进去GraalVM是一个虚拟机，它的次要指标就是晋升java应用程序的性能，并且耗费更少的资源。
它在java HotSpot JVM的根底上增加了JIT编译器和AOT来实现将利用编译成为本地可执行文件。除了java之外，GraalVM还反对JavaScript、Ruby、Python等多种编程语言。
所以，为什么要用GraalVM呢？一个字：快。
装置GraalVM也比较简单，咱们进入它的官网下载页面下载对应的版本即可：https://www.oracle.com/downlo...。
GraalVM跟JDK一样也有两个版本，社区版和企业版本，大家能够依据须要自行抉择。
要留神的是spring boot3须要GraalVM 22.3以上的版本反对，大家可不要下载错了。
下载实现之后，咱们能够像失常装置JDK一样来装置GraalVM,这里以mac为例，如果咱们装置的目录是/Library/Java/JavaVirtualMachines/graalvm-ee-java17-22.3.0，那么咱们须要配置对应的JAVA_HOME和PATH环境变量如下：
export PATH=/Library/Java/JavaVirtualMachines/graalvm-ee-java17-22.3.0/Contents/Home/bin:$PATH export JAVA_HOME=/Library/Java/JavaVirtualMachines/graalvm-ee-java17-22.3.0/Contents/HomePATH中有一个十分重要的命令叫做gu，如果不增加PATH，那么在应用中就可能遇到上面的异样：
'gu' tool wasn't found. This probably means that JDK at isn't a GraalVM distribution.装置结束之后能够通过上面的命令来进行验证：
java -versionjava version "17.0.5" 2022-10-18 LTSJava(TM) SE Runtime Environment GraalVM EE 22.3.0 (build 17.0.5+9-LTS-jvmci-22.3-b07)Java HotSpot(TM) 64-Bit Server VM GraalVM EE 22.3.0 (build 17.0.5+9-LTS-jvmci-22.3-b07, mixed mode, sharing)如果是在mac环境下，还须要执行上面的命令来解除对graalvm的隔离限度：
sudo xattr -r -d com.apple.quarantine /path/to/graalvm否则在应用中就会遇到上面的问题：
增加Native Image反对
咱们装置GraalVM的目标就是应用它的native Image个性。native image是一个独自的jar包，咱们能够执行上面的命令来进行装置：
gu install native-image其中gu就是/Library/Java/JavaVirtualMachines/graalvm-ee-java17-22.3.0/Contents/Home/bin中的命令。
下载的过程中还须要输出一个无效的邮件，并进行邮箱校验。而后一路ENTER就能够了。
当然，你还能够把Oracle GraalVM Enterprise Edition Native Image下载到本地，而后应用gu install -L来进行本地装置。
好了，到目前为止，所有筹备得当，咱们接下来看看如何把spring boot3的利用打包成为native image吧。
构建spring boot3利用
这里咱们应用的是maven，所以须要增加上面的spring boot3的依赖：
<parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>3.0.1</version> <relativePath/> </parent>因为要构建native image，所以咱们还须要用到上面的一个native-maven-plugin插件：
<plugin> <groupId>org.graalvm.buildtools</groupId> <artifactId>native-maven-plugin</artifactId> </plugin>这里咱们只创立了一个非常简单的main办法：
@SpringBootApplicationpublic class NativeImageApplication { public static void main(String[] args) { SpringApplication.run(NativeImageApplication.class, args); }}而后，咱们尝试运行 mvn native:build来构建spring boot3应用程序。
记得在build之前肯定先要编译好我的项目。
很惋惜，你会发现上面的异样：
[INFO] --- native-maven-plugin:0.9.19:build (default-cli) @ native-image ---[WARNING] 'native:build' goal is deprecated. Use 'native:compile-no-fork' instead.[INFO] Found GraalVM installation from JAVA_HOME variable....Error: Please specify class (or <module>/<mainclass>) containing the main entry point method. (see --help)从下面的异样咱们发现了两个问题，第一个问题是一个正告，它举荐咱们应用native:compile-no-fork。
第二个问题是说找不到mainclass,依据异样信息，咱们在pom的plugin中增加上面的配置信息，如下所示：
<plugin> <groupId>org.graalvm.buildtools</groupId> <artifactId>native-maven-plugin</artifactId> <configuration> <!-- imageName用于设置生成的二进制文件名称 --> <imageName>${project.artifactId}</imageName> <!-- mainClass用于指定main办法类门路 --> <mainClass>com.flydean.nativeimage.NativeImageApplication</mainClass> <buildArgs> --no-fallback </buildArgs> </configuration> <executions> <execution> <id>build-native</id> <goals> <goal>compile-no-fork</goal> </goals> <phase>package</phase> </execution> </executions> </plugin>而后从新运行mvn native:compile-no-fork：
GraalVM Native Image: Generating 'native-image' (executable)...========================================================================================================================[1/7] Initializing... (4.3s @ 0.25GB) Version info: 'GraalVM 22.3.0 Java 17 EE' Java version info: '17.0.5+9-LTS-jvmci-22.3-b07' C compiler: cc (apple, arm64, 14.0.0) Garbage collector: Serial GC 1 user-specific feature(s) - org.springframework.aot.nativex.feature.PreComputeFieldFeatureField org.apache.commons.logging.LogAdapter#log4jSpiPresent set to true at build timeField org.apache.commons.logging.LogAdapter#log4jSlf4jProviderPresent set to true at build timeField org.apache.commons.logging.LogAdapter#slf4jSpiPresent set to true at build timeField org.apache.commons.logging.LogAdapter#slf4jApiPresent set to true at build timeField org.springframework.core.NativeDetector#imageCode set to true at build timeField org.springframework.core.KotlinDetector#kotlinPresent set to false at build timeField org.springframework.core.KotlinDetector#kotlinReflectPresent set to false at build timeField org.springframework.format.support.DefaultFormattingConversionService#jsr354Present set to false at build timeField org.springframework.cglib.core.AbstractClassGenerator#imageCode set to true at build time[2/7] Performing analysis... [**********] (24.8s @ 4.57GB) 10,266 (89.50%) of 11,470 classes reachable 16,675 (63.53%) of 26,248 fields reachable 53,776 (60.71%) of 88,575 methods reachable 469 classes, 140 fields, and 2,281 methods registered for reflection 63 classes, 69 fields, and 55 methods registered for JNI access 5 native libraries: -framework CoreServices, -framework Foundation, dl, pthread, z[3/7] Building universe... (5.0s @ 2.72GB)[4/7] Parsing methods... [**] (4.4s @ 2.42GB)[5/7] Inlining methods... [***] (1.3s @ 3.87GB)[6/7] Compiling methods... [********] (70.0s @ 1.04GB)[7/7] Creating image... (4.7s @ 3.35GB) 30.27MB (58.75%) for code area: 30,771 compilation units 20.50MB (39.79%) for image heap: 305,579 objects and 93 resources 769.52KB ( 1.46%) for other data 51.52MB in total------------------------------------------------------------------------------------------------------------------------Top 10 packages in code area: Top 10 object types in image heap: 2.02MB com.oracle.svm.core.code 5.79MB byte[] for code metadata 1.77MB sun.security.ssl 2.31MB byte[] for java.lang.String 1.29MB java.util 2.09MB byte[] for general heap data 929.52KB java.lang.invoke 2.07MB java.lang.String 925.96KB com.sun.crypto.provider 1.76MB java.lang.Class 802.99KB java.lang 671.09KB byte[] for embedded resources 633.35KB sun.nio.ch 567.26KB byte[] for reflection metadata 625.89KB java.util.concurrent 481.22KB com.oracle.svm.core.hub.DynamicHubCompanion 601.86KB org.apache.tomcat.util.net 450.06KB java.util.HashMap$Node 594.48KB sun.security.x509 401.78KB java.util.concurrent.ConcurrentHashMap$Node 20.02MB for 397 more packages 3.40MB for 2297 more object types------------------------------------------------------------------------------------------------------------------------ 9.5s (7.9% of total time) in 50 GCs | Peak RSS: 3.75GB | CPU load: 4.39------------------------------------------------------------------------------------------------------------------------Produced artifacts: /Users/learn-springboot3/learn-springboot3/native-image/target/native-image (executable) /Users/learn-springboot3/learn-springboot3/native-image/target/native-image.build_artifacts.txt (txt)========================================================================================================================Finished generating 'native-image' in 2m 0s.[INFO] ------------------------------------------------------------------------[INFO] BUILD SUCCESS[INFO] ------------------------------------------------------------------------[INFO] Total time: 02:01 min[INFO] Finished at: 2023-01-05T20:43:39+08:00[INFO] ------------------------------------------------------------------------通过漫长的期待，咱们终于build实现了。
因为咱们的artifactId叫做native-image,所以最终在target目录上面生成了一个叫做native-image的可执行文件：
.├── classes│ ├── application.properties│ └── com│ └── flydean│ └── nativeimage│ └── NativeImageApplication.class├── generated-sources│ └── annotations├── generated-test-sources│ └── test-annotations├── maven-archiver│ └── pom.properties├── maven-status│ └── maven-compiler-plugin│ ├── compile│ │ └── default-compile│ │ ├── createdFiles.lst│ │ └── inputFiles.lst│ └── testCompile│ └── default-testCompile│ ├── createdFiles.lst│ └── inputFiles.lst├── native-image├── native-image-0.0.1-SNAPSHOT.jar├── native-image-0.0.1-SNAPSHOT.jar.original├── native-image.build_artifacts.txt├── surefire-reports│ ├── TEST-com.flydean.nativeimage.NativeImageApplicationTests.xml│ └── com.flydean.nativeimage.NativeImageApplicationTests.txt└── test-classes └── com └── flydean └── nativeimage └── NativeImageApplicationTests.class20 directories, 14 files如果你这时候运行target/native-image,那么很可能失去上面的异样：
[main] DEBUG org.springframework.context.aot.AotApplicationContextInitializer - Initializing ApplicationContext with AOT[main] ERROR org.springframework.boot.SpringApplication - Application run failedjava.lang.IllegalArgumentException: Could not find class [com.flydean.nativeimage.NativeImageApplication__ApplicationContextInitializer] at org.springframework.util.ClassUtils.resolveClassName(ClassUtils.java:333)这是因为咱们短少一些spring boot的AOT元文件信息，正确的做法是应用上面的命令：
mvn clean package -Pnative它实际上执行的是上面的几个命令：
mvn spring-boot:process-aotmvn spring-boot:process-test-aotmvn spring-boot:build-image最终咱们失去编译好的native-image信息，运行失去上面的后果：
2023-01-05T17:07:11.692+08:00 INFO 69299 --- [ main] c.f.nativeimage.NativeImageApplication : Starting AOT-processed NativeImageApplication using Java 17.0.5 with PID 69299 (/Users/wayne/data/git/ddean2009/learn-springboot3/learn-springboot3/native-image/target/native-image started by wayne in /Users/wayne/data/git/ddean2009/learn-springboot3/learn-springboot3/native-image)2023-01-05T17:07:11.693+08:00 INFO 69299 --- [ main] c.f.nativeimage.NativeImageApplication : No active profile set, falling back to 1 default profile: "default"2023-01-05T17:07:11.709+08:00 INFO 69299 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)2023-01-05T17:07:11.710+08:00 INFO 69299 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]2023-01-05T17:07:11.710+08:00 INFO 69299 --- [ main] o.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/10.1.4]2023-01-05T17:07:11.717+08:00 INFO 69299 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext2023-01-05T17:07:11.717+08:00 INFO 69299 --- [ main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 24 ms2023-01-05T17:07:11.729+08:00 INFO 69299 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''2023-01-05T17:07:11.729+08:00 INFO 69299 --- [ main] c.f.nativeimage.NativeImageApplication : Started NativeImageApplication in 0.053 seconds (process running for 0.072)总结
从运行状况来看，native-image的启动速度十分快，应该能够晋升不少的性能。
感兴趣的小伙伴连忙用起来吧。
本文的例子https://github.com/ddean2009/learn-springboot3