类加载器

if (this.clazz != null) {
is = this.clazz.getResourceAsStream(this.path);
}
else if (this.classLoader != null) {
is = this.classLoader.getResourceAsStream(this.path);
}
else {
is = ClassLoader.getSystemResourceAsStream(this.path);
}

1.this.clazz.getResourceAsStream(this.path)或this.classLoader.getResourceAsStream(this.path)原理：
首先获取加载该类的类加载器，然后调用getResourceAsStream 最终通过调用
public InputStream getResourceAsStream(String name) {
URL url = getResource(name);
try {
return url != null ? url.openStream() : null;
} catch (IOException e) {
return null;
}
}

public URL getResource(String name) {
URL url;
if (parent != null) {
url = parent.getResource(name);
} else {
url = getBootstrapResource(name);
}
if (url == null) {
url = findResource(name);
}
return url;
}
首先调用父类的加载器，通过递归调用，父类加载器不存在就调用jvm的根类加载器

2.ClassLoader.getSystemResourceAsStream(this.path) 原理：

public static InputStream getSystemResourceAsStream(String name) {
URL url = getSystemResource(name);
try {
return url != null ? url.openStream() : null;
} catch (IOException e) {
return null;
}
}

public static URL getSystemResource(String name) {
ClassLoader system = getSystemClassLoader();
if (system == null) {
return getBootstrapResource(name);
}
return system.getResource(name);
}

直接调用系统类加载器，不存在的话就调用jvm的根类加载器