java - 如何使用 JavaCompiler 获取编译错误消息

Question

这是我用来编译 java 类的代码：

public void javaCompile(String fileName) throws IOException {
    JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
    DiagnosticCollector<JavaFileObject> diagnostics = new DiagnosticCollector<JavaFileObject>();
    StandardJavaFileManager fileManager = compiler.getStandardFileManager(diagnostics, null, null);
    Iterable<? extends JavaFileObject> compilationUnits = fileManager
        .getJavaFileObjectsFromStrings(Arrays.asList(fileName));
    JavaCompiler.CompilationTask task = compiler.getTask(null, fileManager, diagnostics, null,
        null, compilationUnits);
    boolean success = task.call();
    fileManager.close();
    System.out.println("Success: " + success);
}

问题是我想收到有关出现的错误的更多信息（超过 Success: false）。有人能帮我吗？

Answer 1

如果您只想在控制台中打印错误，请不要使用 diagnosticsCollector，如下所示：

    public void javaCompile(String fileName) throws IOException {
        JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
//      DiagnosticCollector<JavaFileObject> diagnostics = new DiagnosticCollector<JavaFileObject>();
        StandardJavaFileManager fileManager = compiler.getStandardFileManager(null/*diagnostics*/, null, null);
        Iterable<? extends JavaFileObject> compilationUnits = fileManager
            .getJavaFileObjectsFromStrings(Arrays.asList(fileName));
        JavaCompiler.CompilationTask task = compiler.getTask(null, fileManager, null/*diagnostics*/, null,
            null, compilationUnits);
        boolean success = task.call();
        fileManager.close();
        System.out.println("Success: " + success);
    }

如果您想以编程方式分析错误，请使用以下命令：

public void javaCompile(String fileName) throws IOException {
    JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
    DiagnosticCollector<JavaFileObject> diagnosticsCollector = new DiagnosticCollector<JavaFileObject>();
    StandardJavaFileManager fileManager = compiler.getStandardFileManager(diagnosticsCollector, null, null);
    Iterable<? extends JavaFileObject> compilationUnits = fileManager.getJavaFileObjectsFromStrings(Arrays.asList(fileName));
    JavaCompiler.CompilationTask task = compiler.getTask(null, fileManager, diagnosticsCollector, null, null, compilationUnits);
    boolean success = task.call();
    if (!success) {
        List<Diagnostic<? extends JavaFileObject>> diagnostics = diagnosticsCollector.getDiagnostics();
        for (Diagnostic<? extends JavaFileObject> diagnostic : diagnostics) {
            // read error dertails from the diagnostic object
            System.out.println(diagnostic.getMessage(null));
        }
    }
    fileManager.close();
    System.out.println("Success: " + success);
}