java内存动态编译执行

标签：http   java   os   io   for   art   re   c   

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<JavaFileObject> diagnostics = new DiagnosticCollector<JavaFileObject>();
ClassFileManager fileManager = new ClassFileManager(compiler.getStandardFileManager(diagnostics, null, null));

List<JavaFileObject> jfiles = new ArrayList<JavaFileObject>();
jfiles.add(new CharSequenceJavaFileObject(fullClassName, javaCode));
List<String> options = new ArrayList<String>();
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 {http://www.huiyi8.com/jiaoben/
String error = ""; javascript特效
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;

java内存动态编译执行,布布扣,bubuko.com

java内存动态编译执行

标签：http   java   os   io   for   art   re   c   

原文地址：http://www.cnblogs.com/cjings/p/3867933.html