Java 由字符串给出的类的编译
我有以下代码:Java 由字符串给出的类的编译,java,class,exception,compilation,Java,Class,Exception,Compilation,我有以下代码: public static void compileClass() { JavaCompiler compiler = ToolProvider.getSystemJavaCompiler(); DiagnosticCollector<JavaFileObject> diagnostics = new DiagnosticCollector<>(); StringWriter writer = new StringWriter()
public static void compileClass() {
JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
DiagnosticCollector<JavaFileObject> diagnostics = new DiagnosticCollector<>();
StringWriter writer = new StringWriter();
PrintWriter out = new PrintWriter(writer);
out.println("package ccc;");
out.println("public class HelloWorld {");
out.println(" public static void main(String args[]) {");
out.println(" System.out.println(\"This is in another java file\");");
out.println(" }");
out.println("}");
out.close();
JavaFileObject file = new JavaSourceFromString("HelloWorld", writer.toString());
Iterable<? extends JavaFileObject> compilationUnits = Arrays.asList(file);
CompilationTask task = compiler.getTask(null, null, diagnostics, null, null, compilationUnits);
boolean success = task.call();
for (Diagnostic diagnostic : diagnostics.getDiagnostics()) {
System.out.println(diagnostic.getCode());
System.out.println(diagnostic.getKind());
System.out.println(diagnostic.getPosition());
System.out.println(diagnostic.getStartPosition());
System.out.println(diagnostic.getEndPosition());
System.out.println(diagnostic.getSource());
System.out.println(diagnostic.getMessage(null));
}
System.out.println("Success: " + success);
if (success) {
try {
Class.forName("ccc.HelloWorld").getDeclaredMethod("main", new Class[]{String[].class})
.invoke(null, new Object[]{null});
} catch (ClassNotFoundException e) {
System.err.println("Class not found: " + e);
} catch (NoSuchMethodException e) {
System.err.println("No such method: " + e);
} catch (IllegalAccessException e) {
System.err.println("Illegal access: " + e);
} catch (InvocationTargetException e) {
System.err.println("Invocation target: " + e);
}
}
}
问题:当运行method compileClass时,所有内容都很清楚,但不一致:
Class.forName("ccc.HelloWorld").getDeclaredMethod("main", new Class[]{String[].class})
.invoke(null, new Object[]{null});
将引发异常:
未找到类:java.lang.ClassNotFoundException:ccc.HelloWorld
该类已编译,但未添加到当前java应用程序的类路径中。您不应该将ccc.HelloWorld传递给JavaSourceFromString而不仅仅是HelloWorld吗?@SotiriosDelimanolis那么,您能告诉我解决方案是什么吗?可以通过编程方式完成吗?
Class.forName("ccc.HelloWorld").getDeclaredMethod("main", new Class[]{String[].class})
.invoke(null, new Object[]{null});