Jdk 动态编译 Java 源码测试 Demo

package org.example.demo.util; import javax.tools.*; import java.nio.charset.StandardCharsets; import java.util.*; import java.util.concurrent.ConcurrentHashMap; /** * 类编译器 * * @author moon * @date 2023-02-15 20:09 * @since 1.8 */ public class CustomClassCompiler { private JavaCompiler javac; private CustomClassLoader classLoader; private Iterable<String> options; boolean ignoreWarnings = false; /** * 缓存待编译的源码 */ private Map<String, CustomSourceCode> sourceCodes = new ConcurrentHashMap<>(16); /** * 缓存生成的类 */ private Map<String, Class<?>> classMap = new ConcurrentHashMap<>(16); /** * 单例编译器 */ private static volatile CustomClassCompiler compiler; /** * 获取实例 * @return */ public static CustomClassCompiler newInstance(ClassLoader parent) { if ( null==compiler ){ synchronized (CustomClassCompiler.class){ if (null==compiler){ compiler = new CustomClassCompiler(); if (null!=parent){ compiler.useParentClassLoader(parent); } } } } return compiler; } /** * 默认类加载器 (私有化构造) */ private CustomClassCompiler() { this.javac = ToolProvider.getSystemJavaCompiler(); this.classLoader = new CustomClassLoader(ClassLoader.getSystemClassLoader()); } /** * 使用父类加载器 * @param parent * @return */ private CustomClassCompiler useParentClassLoader(ClassLoader parent) { this.classLoader = new CustomClassLoader(parent); return this; } /** * @return the class loader used internally by the compiler */ public ClassLoader getClassloader() { return classLoader; } /** * Options used by the compiler, e.g. '-Xlint:unchecked'. * * @param options * @return */ public void useOptions(String... options) { this.options = Arrays.asList(options); } /** * 忽略警告信息 */ public void ignoreWarnings() { ignoreWarnings = true; } /** * 向编译器添加源码 * @param className * @param sourceCode * @return * @throws Exception */ public CustomClassCompiler addSource(String className, String sourceCode) { sourceCodes.put(className, new CustomSourceCode(className, sourceCode)); return this; } /** * 编译源码 * * @param classNames * @return */ public boolean compile(String ... classNames) { try { compileByNames(Arrays.asList(classNames)); return true; } catch (Exception e) { System.out.println("Compile Exception:" + e.getMessage()); return false; } } /** * 获取类 * @param className * @return */ public Class<?> getClassByName(String className){ return classMap.get(className); } /** * 编译源码 * * @return Map containing instances of all compiled classes * @throws Exception */ private void compileByNames(List<String> classNames) throws Exception { if (sourceCodes.size() == 0) { throw new RuntimeException("No source code to compile"); } //获取待编译类源码 Collection<CustomSourceCode> compilationUnits; Set<String> keyTemp = null; if (null != classNames && classNames.size() > 0){ compilationUnits = new ArrayList<>(classNames.size()); keyTemp = new HashSet<>(classNames.size()); for (String key:classNames){ if (sourceCodes.containsKey(key)){ keyTemp.add(key); compilationUnits.add(sourceCodes.get(key)); } } } else { keyTemp = sourceCodes.keySet(); compilationUnits = sourceCodes.values(); } //检测源码是否全部存在 if (keyTemp.size() < classNames.size()){ throw new RuntimeException("Some source code not exist"); } //定义警告和错误信息输出集合 DiagnosticCollector<JavaFileObject> collector = new DiagnosticCollector<>(); CustomJavaFileManager fileManager = new CustomJavaFileManager(javac.getStandardFileManager(null, null, StandardCharsets.UTF_8), classLoader); JavaCompiler.CompilationTask task = javac.getTask(null, fileManager, collector, options, null, compilationUnits); //编译 boolean result = task.call(); //编译结果 if (!result || collector.getDiagnostics().size() > 0) { StringBuffer exceptionMsg = new StringBuffer(); exceptionMsg.append("Unable to compile the source"); boolean hasWarnings = false; boolean hasErrors = false; for (Diagnostic<? extends JavaFileObject> d : collector.getDiagnostics()) { switch (d.getKind()) { case NOTE: case MANDATORY_WARNING: case WARNING: hasWarnings = true; break; case OTHER: case ERROR: hasErrors = true; break; default: break; } exceptionMsg.append("\n").append("[kind=").append(d.getKind()); exceptionMsg.append(", ").append("line=").append(d.getLineNumber()); exceptionMsg.append(", ").append("message=").append(d.getMessage(Locale.US)).append("]"); } //是否忽略警告 if ((hasWarnings && !ignoreWarnings ) || hasErrors) { throw new RuntimeException(exceptionMsg.toString()); } } //遍历并缓存编译后的源码 for (String className : keyTemp) { classMap.put(className, classLoader.loadClass(className)); } } }