在Java 8中构建Maven程序集

Question

我在我的项目中更改了使用的Java版本，现在使用lambda表达式。

如果我使用IDE（IntelliJ）编译，它可以正常运行。但是当我使用maven:assembly编译时，会失败。

以下是输出：

[ERROR] ...../commands/parser/CommandParser.java:[141,73] lambda expressions are not supported in -source 1.5
[ERROR] (use -source 8 or higher to enable lambda expressions)

我的pom.xml文件：

<project xmlns="http://maven.apache.org/POM/4.0.0"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>

<groupId>com.lefrantguillaume</groupId>
<artifactId>ServerTinyTank</artifactId>
<packaging>jar</packaging>
<version>1.0-SNAPSHOT</version>
<url>http://maven.apache.org</url>

<dependencies>
    <dependency>
        <groupId>com.esotericsoftware</groupId>
        <artifactId>kryonet</artifactId>
        <version>2.22.0-RC1</version>
    </dependency>
    <dependency>
        <groupId>com.sun.jersey</groupId>
        <artifactId>jersey-server</artifactId>
        <version>1.9</version>
    </dependency>

    <dependency>
        <groupId>com.sun.jersey</groupId>
        <artifactId>jersey-client</artifactId>
        <version>1.9</version>
    </dependency>
    <dependency>
        <groupId>com.sun.jersey</groupId>
        <artifactId>jersey-json</artifactId>
        <version>1.9</version>
    </dependency>

    <dependency>
        <groupId>com.googlecode.json-simple</groupId>
        <artifactId>json-simple</artifactId>
        <version>1.1</version>
    </dependency>

    <dependency>
        <groupId>args4j</groupId>
        <artifactId>args4j</artifactId>
        <version>2.32</version>
    </dependency>


</dependencies>

<build>
    <plugins>
        <plugin>
            <artifactId>maven-assembly-plugin</artifactId>
            <configuration>
                <source>${java.version}</source>
                <target>${java.version}</target>
                <descriptorRefs>
                    <descriptorRef>jar-with-dependencies</descriptorRef>
                </descriptorRefs>
                <archive>
                    <manifest>
                        <mainClass>com.lefrantguillaume.Main</mainClass>
                    </manifest>
                </archive>
            </configuration>
        </plugin>
    </plugins>
</build>

- Sw0ut

Answer 1

据我所见，您从未设置${java.version}。而且更重要的是，您没有在编译器目标中设置该变量。

以下是正确的设置方式：

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.lefrantguillaume</groupId>
    <artifactId>ServerTinyTank</artifactId>
    <packaging>jar</packaging>
    <version>1.0-SNAPSHOT</version>
    <url>http://maven.apache.org</url>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>com.esotericsoftware</groupId>
            <artifactId>kryonet</artifactId>
            <version>2.22.0-RC1</version>
        </dependency>
        <dependency>
            <groupId>com.sun.jersey</groupId>
            <artifactId>jersey-server</artifactId>
            <version>1.9</version>
        </dependency>
        <dependency>
            <groupId>com.sun.jersey</groupId>
            <artifactId>jersey-client</artifactId>
            <version>1.9</version>
        </dependency>
        <dependency>
            <groupId>com.sun.jersey</groupId>
            <artifactId>jersey-json</artifactId>
            <version>1.9</version>
        </dependency>
        <dependency>
            <groupId>com.googlecode.json-simple</groupId>
            <artifactId>json-simple</artifactId>
            <version>1.1</version>
        </dependency>
        <dependency>
            <groupId>args4j</groupId>
            <artifactId>args4j</artifactId>
            <version>2.32</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.3</version>
                <configuration>
                    <source>${java.version}</source>
                    <target>${java.version}</target>
                </configuration>
            </plugin>
            <plugin>
                <artifactId>maven-assembly-plugin</artifactId>
                <configuration>
                    <source>${java.version}</source>
                    <target>${java.version}</target>
                    <descriptorRefs>
                        <descriptorRef>jar-with-dependencies</descriptorRef>
                    </descriptorRefs>
                    <archive>
                        <manifest>
                            <mainClass>com.lefrantguillaume.Main</mainClass>
                        </manifest>
                    </archive>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

- Boris the Spider

---

工作正常 :D！没有注意到编译器插件。我也缺少了那个。谢谢！ - Sw0ut

Answer 2

            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>

- Amandeep Singh Bhatia

Answer 3

这应该能解决问题

 <source>1.8</source>
 <target>1.8</target>

你在哪里定义你的属性？

- Thomas Junk

Answer 4

或者在pom.xml中使用以下代码，并在Maven Build Run配置中设置目标为'clean package assembly:single'

    <build>
    <plugins>
        <plugin>
            <artifactId>maven-assembly-plugin</artifactId>
            <configuration>
                <archive>
                    <manifest>
                        <mainClass>com.lefrantguillaume.Main</mainClass>
                    </manifest>
                </archive>
                <descriptorRefs>
                    <descriptorRef>jar-with-dependencies</descriptorRef>
                </descriptorRefs>
            </configuration>
        </plugin>
    </plugins>
  </build>

- Ash