java内存动态编译执行

1.package org.jui.core.dynamic; 
public class DynaCompTest {
    public static void main(String[] args) throws Exception {
        String fullName = "DynaClass";
        StringBuilder src = new StringBuilder();
        src.append("public class DynaClass {\n");
        src.append("    public String toString() {\n");
        src.append("        return \"Hello, I am \" + ");
        src.append("this.getClass().getSimpleName();\n");
        src.append("    }\n");
        src.append("}\n");
 
        System.out.println(src);
        DynamicEngine de = DynamicEngine.getInstance();
        Object instance =  de.javaCodeToObject(fullName,src.toString());
        System.out.println(instance);
2.package org.jui.core.dynamic;
 
import javax.tools.*;
import java.util.ArrayList;
import java.util.List;
import java.util.Arrays;
import java.net.URL;
import java.net.URLClassLoader;
import java.io.File;
 
public class DynamicEngine {
    private static DynamicEngine ourInstance = new DynamicEngine();
 
    public static DynamicEngine getInstance() {
        return ourInstance;
    }
    private URLClassLoader parentClassLoader;
    private String classpath;
    private DynamicEngine() {
        this.parentClassLoader = (URLClassLoader) this.getClass().getClassLoader();
        this.buildClassPath();
    }
    private void buildClassPath() {
        this.classpath = null;
        StringBuilder sb = new StringBuilder();
        for (URL url : this.parentClassLoader.getURLs()) {
            String p = url.getFile();
            sb.append(p).append(File.pathSeparator);
        }
        this.classpath = sb.toString();
    }
    public Object javaCodeToObject(String fullClassName, String javaCode) throws IllegalAccessException, InstantiationException {
        long start = System.currentTimeMillis();
        Object instance = null;
        JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
        DiagnosticCollector diagnostics = new DiagnosticCollector();
        ClassFileManager fileManager = new ClassFileManager(compiler.getStandardFileManager(diagnostics, null, null));
 
        List jfiles = new ArrayList();
        jfiles.add(new CharSequenceJavaFileObject(fullClassName, javaCode));
        List options = new ArrayList();
        options.add("-encoding");
        options.add("UTF-8");
        options.add("-classpath");
        options.add(this.classpath);
 
        JavaCompiler.CompilationTask task = compiler.getTask(null, fileManager, diagnostics, options, null, jfiles);
        boolean success = task.call();
 
        if (success) {
            JavaClassObject jco = fileManager.getJavaClassObject();
            DynamicClassLoader dynamicClassLoader = new DynamicClassLoader(this.parentClassLoader);
            Class clazz = dynamicClassLoader.loadClass(fullClassName,jco);
            instance = clazz.newInstance();
        } else { 
            String error = "";
            for (Diagnostic diagnostic : diagnostics.getDiagnostics()) {
                error = error + compilePrint(diagnostic);
        long end = System.currentTimeMillis();
        System.out.println("javaCodeToObject use:"+(end-start)+"ms");
        return instance;
    private String compilePrint(Diagnostic diagnostic) {
        System.out.println("Code:" + diagnostic.getCode());
        System.out.println("Kind:" + diagnostic.getKind());
        System.out.println("Position:" + diagnostic.getPosition());
        System.out.println("Start Position:" + diagnostic.getStartPosition());
        System.out.println("End Position:" + diagnostic.getEndPosition());
        System.out.println("Source:" + diagnostic.getSource());
        System.out.println("Message:" + diagnostic.getMessage(null));
        System.out.println("LineNumber:" + diagnostic.getLineNumber());
        System.out.println("ColumnNumber:" + diagnostic.getColumnNumber());
        StringBuffer res = new StringBuffer();
        res.append("Code:[" + diagnostic.getCode() + "]\n");
        res.append("Kind:[" + diagnostic.getKind() + "]\n");
        res.append("Position:[" + diagnostic.getPosition() + "]\n");
        res.append("Start Position:[" + diagnostic.getStartPosition() + "]\n");
        res.append("End Position:[" + diagnostic.getEndPosition() + "]\n");
        res.append("Source:[" + diagnostic.getSource() + "]\n");
        res.append("Message:[" + diagnostic.getMessage(null) + "]\n");
        res.append("LineNumber:[" + diagnostic.getLineNumber() + "]\n");
        res.append("ColumnNumber:[" + diagnostic.getColumnNumber() + "]\n");
        return res.toString();
3.package org.jui.core.dynamic;
import javax.tools.JavaFileObject;
import javax.tools.SimpleJavaFileObject;
import java.net.URI;
 
public class CharSequenceJavaFileObject extends SimpleJavaFileObject {
    private CharSequence content;
    public CharSequenceJavaFileObject(String className,
                                      CharSequence content) {
        super(URI.create("string:///" + className.replace('.', '/')
                + JavaFileObject.Kind.SOURCE.extension), JavaFileObject.Kind.SOURCE);
        this.content = content;
    @Override
    public CharSequence getCharContent(
            boolean ignoreEncodingErrors) {
        return content;
4.package org.jui.core.dynamic;
 
import javax.tools.*;
import java.io.IOException;
import java.security.SecureClassLoader;
 
public class ClassFileManager extends
        ForwardingJavaFileManager {
    public JavaClassObject getJavaClassObject() {
        return jclassObject;
    private JavaClassObject jclassObject;
    public ClassFileManager(StandardJavaFileManager
        standardManager) {
        super(standardManager);
    @Override
    public JavaFileObject getJavaFileForOutput(Location location,
        String className, JavaFileObject.Kind kind, FileObject sibling)
            throws IOException {
            jclassObject = new JavaClassObject(className, kind);
        return jclassObject;