java - Spark Java错误:lambda expressions are not supported in -source 1. 5

Question

这个问题已经有答案了:

maven. lambda expressions are not supported in -source 1.5 (3 个回答)

已关闭 6 年前。

从 http://spark.apache.org 获取以下代码。我遇到以下错误....

代码:

JavaRDD<String> lines = sc.textFile(logFile);
JavaPairRDD<String, Integer> pairs = lines.mapToPair(s -> new Tuple2(s, 1));

错误:

-source 1.5 不支持 lambda 表达式(使用 -source 8 或更高版本启用 lambda 表达式)

但是下面的代码工作得很好。您能帮我找出原因吗？

新代码:

JavaRDD<String> lines = sc.textFile(logFile);
JavaPairRDD<String, String> prodPairs = lines.mapToPair(new PairFunction<String, String, String>() {
            public Tuple2<String, String> call(String s) {
                String[] prodSplit = s.split(",");
                return new Tuple2<String, String>(prodSplit[2], prodSplit[0]+","+prodSplit[1]+","+prodSplit[2]); 
            }
        });

Answer 1

你使用maven吗？

默认情况下，maven 使用源代码和目标编译为 java 1.5:

Also note that at present the default source setting is 1.5 and thedefault target setting is 1.5, independently of the JDK you run Mavenwith. If you want to change these defaults, you should set source andtarget as described in Setting the -source and -target of the JavaCompiler. Source

您需要在pom构建编译器插件中配置:

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.2</version>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
            </configuration>
        </plugin>
    </plugins>
</build>