Question

我的代码是：

public class StanfordTagger {

    public static void main(String[] args)throws IOException, ClassNotFoundException
    {             
        System.out.println("Starting Stanford Part of Speech Tagger");
        //get file name with path from user
        Scanner keyboard = new Scanner(System.in);
        System.out.print("Enter the path and filename to tag: ");
        String fileName = keyboard.nextLine();

        String line = null;
        // FileReader reads text files in the default encoding.
        FileReader fileReader = 
            new FileReader(fileName);

        // Always wrap FileReader in BufferedReader.
        BufferedReader bufferedReader = 
            new BufferedReader(fileReader);

        String newFileName = fileName.replace(".txt", "POSTagger.txt");
        //create a FileWriter using the new path and file
        FileWriter fileWriter = new FileWriter(newFileName);
        // Always wrap FileWriter in BufferedWriter.
        BufferedWriter bufferedWriter = new BufferedWriter(fileWriter);


        /* creates a StanfordCoreNLP object, with POS tagging, lemmatization, NER, parsing, and coreference resolution 
        Properties props = new Properties();
        props.setProperty("annotators", "tokenize, ssplit, pos, lemma, ner, parse, dcoref");
        StanfordCoreNLP pipeline = new StanfordCoreNLP(props);*/


        // Initialize the tagger with a model
        MaxentTagger tagger = new MaxentTagger(
        "G:\\Natural Language Final Project\\taggers\\english-left3words-distsim.tagger");

        while((line = bufferedReader.readLine()) != null) {
            System.out.println(tagger.tagString(line));
            bufferedWriter.write(tagger.tagString(line)+"\n");
        }      

        // Always close files.
        bufferedReader.close(); 
        bufferedWriter.flush();
        bufferedWriter.close();

    }
}

我跑的错误是：

Enter the path and filename to tag: G:\Natural Language Final Project\tasks_1-20_v1-2\en\qa6_yes-no-questions_test.txt
Exception in thread "main" java.lang.UnsupportedClassVersionError: edu/stanford/nlp/tagger/maxent/MaxentTagger : Unsupported major.minor version 52.0
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:792)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
    at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at StanfordTagger.main(StanfordTagger.java:78)
Java Result: 1
BUILD SUCCESSFUL (total time: 39 seconds)

有谁知道我需要做些什么来解决这个问题？

Answer 1

您使用较新的JVM。

新的JVM可以支持加载（大多数）旧类版本。较旧的JVM无法加载创建JVM时不存在的类版本。

从类版本（52）开始，您尝试在Java 7或更低版本的JVM上运行在Java 8环境中编译的代码。

Answer 2

“当JVM尝试加载类并发现类文件版本为不支持它抛出UnSupportedClassVersionError和它一般如果使用更高的JDK版本来编译源文件，则会发生较低的JDK版本用于运行程序。“

确定您使用相同（或次要）Java版本编译代码来运行它。

您正尝试在Java 6（例如）JVM上运行Java 8（例如）编译代码。

我的Java程序有java.lang.UnsupportedClassVersionError。我该如何解决这个问题？

2 个答案: