自定义类加载器的实现，类加载过程

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代码如下：

package classloader;

import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

public class MyClassLoader extends ClassLoader {

	private String name;//类加载器的名字
	
	private String path = "/home/chiwei/mydisk/eclipse_workspace/java/src/";//类加载的路径
	
	private final String fileType = ".class";
	
	public MyClassLoader(String name) {
		super();
		this.name = name;
	}
	
	public String getPath() {
		return path;
	}

	public void setPath(String path) {
		this.path = path;
	}

	private byte[] loadClassData(String name) {
		InputStream in = null;
		byte[] data = null;
		ByteArrayOutputStream baos = null;
		try {
			name = name.replace(".", "\\");
			in = new BufferedInputStream(new FileInputStream(new File(path+name+fileType)));
			baos = new ByteArrayOutputStream();
			int ch = 0;
			while((ch=in.read())!=-1) {
				baos.write(ch);
			}
			data = baos.toByteArray();
		}catch(Exception e) {
			e.printStackTrace();
		}finally {
			try {
				baos.close();
				in.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		return data;
	}
	
	protected Class<?> findClass(String name) {
		byte[] data = this.loadClassData(name);
		return this.defineClass(name, data, 0,data.length);
	}

	public static void main(String[] args) throws Exception{
		// TODO Auto-generated method stub
		MyClassLoader loader1 = new MyClassLoader("loader1");
		loader1.setPath("");
		test(loader1);
	}
	
	public static void test(ClassLoader loader) throws Exception{
		Class<?> clazz = loader.loadClass("classloader.MyString");
		Object object = clazz.newInstance();
		MyString ms = (MyString)object;
		System.out.println(ms.toString());
		System.out.println(object==null);
		System.out.println(object.hashCode());
	}

}

package classloader;

public class MyString {

	public java.lang.String toString() {
		return "这是我自定义的String类的toString方法";
	}
	
}

这是我自定义的String类的toString方法
false
926509297

自定义类加载器的实现，类加载过程

标签：style   blog   io   ar   color   os   sp   java   文件   

原文地址：http://blog.csdn.net/simonchi/article/details/41485323