Java类热替换（热部署）源码

import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.lang.reflect.Method; import java.util.Arrays; import java.util.HashSet; import java.util.Set; /** * 自定义类加载器 * * @author sunhf * */ public class CustomCL extends ClassLoader { private String path; private Set<String> clazzs; public CustomCL(String path, String[] clazzs) { super(null); // 不使用父类实现 this.clazzs = new HashSet<String>(Arrays.asList(clazzs)); this.path = path; onBoot(clazzs); } private void onBoot(String[] clazzs) { for (String name : clazzs) { defClass(name); } } private Class<?> defClass(String name) { String diskUrl = path + name.replace('.', File.separatorChar) + ".class"; Class<?> clazz = null; try { File clazzF = new File(diskUrl); FileInputStream stream = new FileInputStream(clazzF); int len = (int) clazzF.length(); byte[] b = new byte[len]; stream.read(b); stream.close(); int off = 0; clazz = defineClass(name, b, off, b.length); } catch (IOException e) { e.printStackTrace(); } return clazz; } /** * 读取类 */ @Override public Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException { Class<?> clazz = findLoadedClass(name); if (!this.clazzs.contains(name) && clazz == null) { clazz = getSystemClassLoader().loadClass(name); } if (clazz == null) { throw new ClassNotFoundException(name); } if (resolve == true) { resolveClass(clazz); } return clazz; } /** * 加载类 */ @Override protected Class<?> findClass(String name) throws ClassNotFoundException { return super.findClass(name); } }