JavaCompiler使用例子

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package com.test;

import java.io.IOException;
import java.lang.reflect.Method;
import java.net.URI;
import java.util.Arrays;

import javax.tools.JavaCompiler;
import javax.tools.JavaFileObject;
import javax.tools.SimpleJavaFileObject;
import javax.tools.StandardJavaFileManager;
import javax.tools.ToolProvider;

public class CompileString {
    public static void main(String[] args) throws Exception {
        JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
        System.out.println(""+ToolProvider.getSystemJavaCompiler());
        StandardJavaFileManager fileManager = compiler.getStandardFileManager(
                null, null, null);

        StringObject so = new StringObject(
                "CalculatorTest",
                "class CalculatorTest {"
                        + " public int multiply(int multiplicand, int multiplier) {"
                        + " System.out.println(multiplicand);"
                        + " System.out.println(multiplier);"
                        + " return multiplicand * multiplier;" + " }" + "}");

JavaFileObject file = so;

        Iterable files = Arrays.asList(file);
        JavaCompiler.CompilationTask task = compiler.getTask(null, fileManager,
                null, null, null, files);

        Boolean result = task.call();
        System.out.println(result);
        if (result) {
            Class clazz = Class.forName("CalculatorTest");

Object instance = clazz.newInstance();

Method m = clazz.getMethod("multiply", new Class[] { int.class,
int.class });

            Object[] o = new Object[] { 3, 2 };
            System.out.println(m.invoke(instance, o));
        }
    }
}

class StringObject extends SimpleJavaFileObject {
private String contents = null;

    public StringObject(String className, String contents) throws Exception {
        super(URI.create("string:///" + className.replace('.', '/')
                + Kind.SOURCE.extension), Kind.SOURCE);
        this.contents = contents;
    }

    public CharSequence getCharContent(boolean ignoreEncodingErrors)
            throws IOException {
        return contents;
    }
}