今天看了ClassLoader基本原理,想自定义个ClassLoader加载类,对任何路径的class类都实用,代码如下:
package test;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import org.apache.commons.io.FileUtils;
public class MyClassLoader extends ClassLoader {
@Override
protected Class<?> findClass(String name) throws ClassNotFoundException {
String path = null;
String[] names = null;
try {
path = super.getSystemResource("").getPath();
names = name.split("/");
FileUtils.copyFile(new File(name), new File(path+"/"+(getPkgname()+"\\.").replaceAll("\\.", "/")+names[names.length-1]));
} catch (IOException e) {
e.printStackTrace();
}
String classname = getPkgname()+"."+names[names.length-1].split("\\.")[0];
return super.getSystemClassLoader().loadClass(classname);
}
private String pkgname;
public String getPkgname() {
return pkgname;
}
public void setPkgname(String pkgname) {
this.pkgname = pkgname;
}
}
public static void main(String[] args) throws SQLException {
try {
MyClassLoader my = new MyClassLoader();
my.setPkgname("test");
Class c = my.findClass("D:/Test2.class");
Object o = c.newInstance();
Method[] methods = c.getDeclaredMethods();
for (int i = 0; i < methods.length; i++) {
System.out.println(methods[i].getName());
methods[i].invoke(o, null);
}
} catch (Exception e) {
e.printStackTrace();
}
package test;
public class Test2 {
public void printa(){
System.out.println("xixi");
}
}
以上分别为自定义类,测试运行类和被加载类。
代码很简单,现在问题是类似这种加载classpath外的绝对路径的类java本身的ClassLoader没有这样的方法吗?然后我这样自定义的Classloader怎么在加载时启动?不可能想上面这样直接调用加载器的方法吧,求csdn大神指点!