Project获取资源需要一个启点，加载资源的动作是由ClassLoader来完成的。
Class对象和当前线程对象可以找到当前加载资源的ClassLoader，
通过ClassLoader的getResource(String name)方法及其它衍生出来的方法可以找到Application的启点及获取相关资源

private void display() {

        path=this.getClass().getResource("/loadresource").getPath();

        System.out.println(path);

        path=this.getClass().getResource("/loadresource/bp.txt").getPath();

        System.out.println(path);

        path=this.getClass().getResource("/").getPath();

        System.out.println(path);

        URL url=this.getClass().getResource("loadresource/bp.txt");

        System.out.println("Is Null:"+(url==null));

        path=GetResouceTest.class.getClassLoader().getResource("").getPath();

        System.out.println(path);

        path=GetResouceTest.class.getClassLoader().getResource("loadresource/bp.txt").getPath();

        System.out.println(path);

        url=GetResouceTest.class.getClassLoader().getResource("/loadresource/bp.txt");

        System.out.println("Is Null:"+(url==null));

        path=Thread.currentThread().getContextClassLoader().getResource("").getPath();

        System.out.println(path);

        path=Thread.currentThread().getContextClassLoader().getResource("loadresource/bp.txt").getPath();

        System.out.println(path);

        url=Thread.currentThread().getContextClassLoader().getResource("loadresource/bp.txt");

        System.out.println("Is Null:"+(url==null));

        url=Thread.currentThread().getContextClassLoader().getResource("/loadresource/bp.txt");

        System.out.println("Is Null:"+(url==null));

    }

/E:/java/workspace/test/bin/loadresource

/E:/java/workspace/test/bin/loadresource/bp.txt

/E:/java/workspace/test/bin/

Is Null:true

/E:/java/workspace/test/bin/

/E:/java/workspace/test/bin/loadresource/bp.txt

Is Null:true

/E:/java/workspace/test/bin/

/E:/java/workspace/test/bin/loadresource/bp.txt

Is Null:false

Is Null:true

 /**

     * Finds a resource with a given name.  The rules for searching resources

     * associated with a given class are implemented by the defining

     * {@linkplain ClassLoader class loader} of the class.  This method

     * delegates to this object's class loader.  If this object was loaded by

     * the bootstrap class loader, the method delegates to {@link

     * ClassLoader#getSystemResource}.

     *

     * <p> Before delegation, an absolute resource name is constructed from the

     * given resource name using this algorithm:

     *

     * <ul>

     *

     * <li> If the {@code name} begins with a {@code '/'}

     * (<tt>'\u002f'</tt>), then the absolute name of the resource is the

     * portion of the {@code name} following the {@code '/'}.

     *

     * <li> Otherwise, the absolute name is of the following form:

     *

     * <blockquote>

     *   {@code modified_package_name/name}

     * </blockquote>

     *

     * <p> Where the {@code modified_package_name} is the package name of this

     * object with {@code '/'} substituted for {@code '.'}

     * (<tt>'\u002e'</tt>).

     *

     * </ul>

     *

     * @param  name name of the desired resource

     * @return      A  {@link java.net.URL} object or {@code null} if no

     *              resource with this name is found

     * @since  JDK1.1

     */

    public java.net.URL getResource(String name) {

        name = resolveName(name);

        ClassLoader cl = getClassLoader0();

        if (cl==null) {

            // A system class.

            return ClassLoader.getSystemResource(name);

        }

        return cl.getResource(name);

    }

   /**

     * Add a package name prefix if the name is not absolute Remove leading "/"

     * if name is absolute

     */

    private String resolveName(String name) {

        if (name == null) {

            return name;

        }

        if (!name.startsWith("/")) {

            Class<?> c = this;

            while (c.isArray()) {

                c = c.getComponentType();

            }

            String baseName = c.getName();

            int index = baseName.lastIndexOf('.');

            if (index != -1) {

                name = baseName.substring(0, index).replace('.', '/')

                    +"/"+name;

            }

        } else {

            name = name.substring(1);
        }

        return name;

    }