java.io.FileNotFoundException: /storage/emulated/0/DCIM/Camera/b6badecd-32a9-48a2-b0fe-25b0bfbc5d0f.

在项目中保存网络图片到手机本地时，保存图片失败，出现这种原因的话有可能是下面原因：

Android 6.0 中，有些权限属于 Protected Permission，这类权限只在 AndroidManifest.xml中声明是无法真正获取到的，还需要再代码中动态获取，使权限许可弹出对话框，用户点击“允许”后，方可真正获得此权限

1.清单文件中没有对应的权限：

2.如果不写以上代码，还可以用另外一种简单简单粗暴的方式：直接在6.0的设置里面找到应用，选中你的APP->权限->打开存储空间权限

3.添加动态权限：

/**
         * 动态获取权限，Android 6.0 新特性，一些保护权限，除了要在AndroidManifest中声明权限，还要使用如下代码动态获取
         */
        if (Build.VERSION.SDK_INT >= 23) {
            int REQUEST_CODE_CONTACT = 101;
            String[] permissions = {Manifest.permission.WRITE_EXTERNAL_STORAGE};
            //验证是否许可权限
            for (String str : permissions) {
                if (this.checkSelfPermission(str) != PackageManager.PERMISSION_GRANTED) {
                    //申请权限
                    this.requestPermissions(permissions, REQUEST_CODE_CONTACT);
                    return;
                }
            }
        }

或

 // 6.0及以上的系统需要在运行时申请CAMERA RECORD_AUDIO权限
                                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                                    if (ContextCompat.checkSelfPermission(PhotoDetailActivity.this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED
                                            || ContextCompat.checkSelfPermission(PhotoDetailActivity.this, Manifest.permission.RECORD_AUDIO) != PackageManager.PERMISSION_GRANTED
                                            || ContextCompat.checkSelfPermission(PhotoDetailActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED
                                            || ContextCompat.checkSelfPermission(PhotoDetailActivity.this, Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED
                                            || ContextCompat.checkSelfPermission(PhotoDetailActivity.this, Manifest.permission.READ_SMS) != PackageManager.PERMISSION_GRANTED) {
                                        ActivityCompat.requestPermissions(PhotoDetailActivity.this, new String[]{
                                                Manifest.permission.CAMERA, Manifest.permission.RECORD_AUDIO
                                                , Manifest.permission.WRITE_EXTERNAL_STORAGE
                                                , Manifest.permission.READ_EXTERNAL_STORAGE
                                                , Manifest.permission.READ_SMS}, 101);
                                    }
                                }