java之如何设置使用--enable-preview从gradle编译并运行标志

Looking在records构建中使用Java 14中的gradle，但正在获取:

thufir@dur:~/NetBeansProjects/FileWatcherHandler$  
thufir@dur:~/NetBeansProjects/FileWatcherHandler$ gradle clean build 
 
> Task :compileJava FAILED 
/home/thufir/NetBeansProjects/FileWatcherHandler/src/main/java/net/bounceme/dur/files/FXOrder.java:3: error: records are a preview feature and are disabled by default. 
public record FXOrder(int units) {} 
       ^ 
  (use --enable-preview to enable records) 
1 error 
 
FAILURE: Build failed with an exception. 
 
* What went wrong: 
Execution failed for task ':compileJava'. 
> Compilation failed; see the compiler error output for details. 
 
* Try: 
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights. 
 
* Get more help at https://help.gradle.org 
 
BUILD FAILED in 641ms 
2 actionable tasks: 1 executed, 1 up-to-date 
thufir@dur:~/NetBeansProjects/FileWatcherHandler$             

用 javac编译看起来还可以:

thufir@dur:~/java$  
thufir@dur:~/java$ ls 
FXOrder.java 
thufir@dur:~/java$  
thufir@dur:~/java$ cat FXOrder.java  
 
public record FXOrder(int units) {} 
thufir@dur:~/java$  
thufir@dur:~/java$ javac --enable-preview -source 14 FXOrder.java  
Note: FXOrder.java uses preview language features. 
Note: Recompile with -Xlint:preview for details. 
thufir@dur:~/java$  
thufir@dur:~/java$ ls 
FXOrder.class  FXOrder.java 
thufir@dur:~/java$  

如何在以下构建文件中设置那些编译选项:

/* 
 * This file was generated by the Gradle 'init' task. 
 * 
 * This generated file contains a sample Java project to get you started. 
 * For more details take a look at the Java Quickstart chapter in the Gradle 
 * User Manual available at https://docs.gradle.org/6.4.1/userguide/tutorial_java_projects.html 
 */ 
 
plugins { 
    // Apply the java plugin to add support for Java 
    id 'java' 
 
    // Apply the application plugin to add support for building a CLI application. 
    id 'application' 
} 
 
repositories { 
    // Use jcenter for resolving dependencies. 
    // You can declare any Maven/Ivy/file repository here. 
    jcenter() 
} 
 
dependencies { 
    // This dependency is used by the application. 
    implementation 'com.google.guava:guava:28.2-jre' 
 
    // Use TestNG framework, also requires calling test.useTestNG() below 
    testImplementation 'org.testng:testng:7.1.1' 
} 
 
application { 
    // Define the main class for the application. 
//    mainClassName = 'FileWatcherHandler.App' 
    mainClassName = 'net.bounceme.dur.files.App' 
 
 
} 
 
test { 
    // Use TestNG for unit tests 
    useTestNG() 
} 

Java版本:

thufir@dur:~/java$  
thufir@dur:~/java$ gradle --version 
 
------------------------------------------------------------ 
Gradle 6.4.1 
------------------------------------------------------------ 
 
Build time:   2020-05-15 19:43:40 UTC 
Revision:     1a04183c502614b5c80e33d603074e0b4a2777c5 
 
Kotlin:       1.3.71 
Groovy:       2.5.10 
Ant:          Apache Ant(TM) version 1.10.7 compiled on September 1 2019 
JVM:          14.0.1 (AdoptOpenJDK 14.0.1+7) 
OS:           Linux 5.4.0-29-generic amd64 
 
thufir@dur:~/java$  
thufir@dur:~/java$ java --version 
openjdk 14.0.1 2020-04-14 
OpenJDK Runtime Environment AdoptOpenJDK (build 14.0.1+7) 
OpenJDK 64-Bit Server VM AdoptOpenJDK (build 14.0.1+7, mixed mode, sharing) 
thufir@dur:~/java$  
thufir@dur:~/java$ javac --version 
javac 14.0.1 
thufir@dur:~/java$  
thufir@dur:~/java$ which java 
/home/thufir/.sdkman/candidates/java/current/bin/java 
thufir@dur:~/java$  

请您参考如下方法:

为此，您可以修改compileJava任务并添加此标志。将此添加到您的build.gradle中:

compileJava { 
    options.compilerArgs += ['--enable-preview'] 
} 

这样可以确保您的代码可以编译。

如果还有其他需要编译的任务(例如 compileTestJava)，则可以为所有类型为 JavaCompile的任务启用此标志:

tasks.withType(JavaCompile).all { 
    options.compilerArgs += ['--enable-preview'] 
} 

要为测试任务启用此标志，您可以执行以下操作:

tasks.withType(Test).all { 
    jvmArgs += '--enable-preview' 
} 

您还必须确保为将运行您的代码的JVM添加此标志:

tasks.withType(JavaExec) { 
    jvmArgs += '--enable-preview' 
} 

这在相应的 JEP中进行了描述:

Developers who wish to use preview language features in their programs must explicitly enable them in the compiler and the runtime system