Java 启用预览特性

向右看齐 2022-12-07 01:23 239阅读 0赞

# 问题 #

从Java 13开始支持文本块（多行字符串），可以替代从前丑陋的多行字符串拼接。即使是 Java14 该特性也是预览特性。

报错如下：`Text Blocks is a preview feature and disabled by default. Use --enable-preview to enable`  
![在这里插入图片描述][20200914192840925.png]

# 解决方案 #

## eclipse ##

![在这里插入图片描述][20200914183712752.png]

## maven ##

修改 pom.xml 文件

<project>
    	...
    	<properties>
    		<java.version>13</java.version>
    		<maven.compiler.source>13</maven.compiler.source>
    		<maven.compiler.target>13</maven.compiler.target>
    	</properties>
    	
    	<build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                    <configuration>
                        <arguments>--enable-preview</arguments>
                        <jvmArguments>--enable-preview</jvmArguments>
                    </configuration>
                </plugin>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-surefire-plugin</artifactId>
                    <version>2.22.2</version>
                    <configuration>
                        <argLine>--enable-preview</argLine>
                    </configuration>
                </plugin>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.8.1</version>
                    <configuration>
                        <compilerArgs>--enable-preview</compilerArgs>
                    </configuration>
                </plugin>
            </plugins>
        </build>
    	...
    </project>

## gradle ##

在 build.gradle 里添加

tasks.withType(JavaCompile) {
        options.compilerArgs += "--enable-preview"
    }

## 命令行 ##

编译 `javac --enable-preview -source 13 -encoding utf-8 test.java`

执行 `java --enable-preview test`

[20200914192840925.png]: /images/20221123/0086817389ae41ba8514f2303ea97b8d.png
[20200914183712752.png]: /images/20221123/a5c53010ec5b4e31a69b2c0d6c1f57d9.png