这篇教程主要介绍如何使用摄像头还有相册，还介绍如何将获取到的照片上传至服务器保存（这里主要是用到了阿里云的对象存储OSS服务）
应用场景：APP中“我的”界面或者“个人中心”界面，个人头像选择及存储问题！

一、前端创建Android项目

1、布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
    <Button
        android:id="@+id/take_photo"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:backgroundTint="#E91E63"
        android:text="Take Photo" />
    <Button
        android:id="@+id/choose_from_album"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:backgroundTint="#E91E63"
        android:text="Choose From Album" />
    <Button
        android:id="@+id/upload"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:backgroundTint="#E91E63"
        android:onClick="upload"
        android:text="上传" />
    <ImageView
        android:id="@+id/picture"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal" />
</LinearLayout>

2、AndroidManifest.xml申请权限

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
 	<application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:requestLegacyExternalStorage="true"
        android:networkSecurityConfig="@xml/network_security_config"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.Login">
        <activity android:name=".Avatarupload">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>  
    </application>

android:requestLegacyExternalStorage=“true”:targetSdkVersion<29 的应用程序默认带有requestLegacyExternalStorage=true属性,如果targetSdkVersion>30就加上这句话，还有网络权限，还需要在配置一下android:networkSecurityConfig="@xml/network_security_config"
network_security_config.xml

<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
    <base-config cleartextTrafficPermitted="true" />
</network-security-config>

3、Avatarupload.java

public class Avatarupload extends AppCompatActivity {


    public static final int TAKE_PHOTO = 1;

    public static final int CHOOSE_PHOTO = 2;

    private ImageView picture;

    private Button takePhoto;

    private Button chooseFromAlbum;

    private Uri imageUri;

    private String imagePath = null;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_avatarupload);
        takePhoto = (Button) findViewById(R.id.take_photo);
        chooseFromAlbum = (Button) findViewById(R.id.choose_from_album);
        picture = (ImageView) findViewById(R.id.picture);
        takePhoto.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // 创建File对象，用于存储拍照后的图片
                File outputImage = new File(getExternalCacheDir(), "output_image.jpg");
                try {
                    if (outputImage.exists()) {
                        outputImage.delete();
                    }
                    outputImage.createNewFile();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (Build.VERSION.SDK_INT < 24) {
                    imageUri = Uri.fromFile(outputImage);
                } else {
                    imageUri = FileProvider.getUriForFile(Avatarupload.this, "com.example.cameraalbumtest.fileprovider", outputImage);
                }
                // 启动相机程序
                Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
                intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
                startActivityForResult(intent, TAKE_PHOTO);
            }
        });
        chooseFromAlbum.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (ContextCompat.checkSelfPermission(Avatarupload.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
                    ActivityCompat.requestPermissions(Avatarupload.this, new String[]{ Manifest.permission. WRITE_EXTERNAL_STORAGE }, 1);
                } else {
                    openAlbum();
                }
            }
        });
    }

    private void openAlbum() {
        Intent intent = new Intent("android.intent.action.GET_CONTENT");
        intent.setType("image/*");
        startActivityForResult(intent, CHOOSE_PHOTO); // 打开相册
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        switch (requestCode) {
            case 1:
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    openAlbum();
                } else {
                    Toast.makeText(this, "You denied the permission", Toast.LENGTH_SHORT).show();
                }
                break;
            default:
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        switch (requestCode) {
            case TAKE_PHOTO:
                if (resultCode == RESULT_OK) {
                    try {
                        // 将拍摄的照片显示出来
                        Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageUri));
                        picture.setImageBitmap(bitmap);
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
                break;
            case CHOOSE_PHOTO:
                if (resultCode == RESULT_OK) {
                    // 判断手机系统版本号
                    if (Build.VERSION.SDK_INT >= 19) {
                        // 4.4及以上系统使用这个方法处理图片
                        handleImageOnKitKat(data);
                    } else {
                        // 4.4以下系统使用这个方法处理图片
                        handleImageBeforeKitKat(data);
                    }
                }
                break;
            default:
                break;
        }
    }

    @TargetApi(19)
    private void handleImageOnKitKat(Intent data) {

        Uri uri = data.getData();
        Log.d("TAG", "handleImageOnKitKat: uri is " + uri);
        if (DocumentsContract.isDocumentUri(this, uri)) {
            // 如果是document类型的Uri，则通过document id处理
            String docId = DocumentsContract.getDocumentId(uri);
            if("com.android.providers.media.documents".equals(uri.getAuthority())) {
                String id = docId.split(":")[1]; // 解析出数字格式的id
                String selection = MediaStore.Images.Media._ID + "=" + id;
                imagePath = getImagePath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, selection);
            } else if ("com.android.providers.downloads.documents".equals(uri.getAuthority())) {
                Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.valueOf(docId));
                imagePath = getImagePath(contentUri, null);
            }
        } else if ("content".equalsIgnoreCase(uri.getScheme())) {
            // 如果是content类型的Uri，则使用普通方式处理
            imagePath = getImagePath(uri, null);
        } else if ("file".equalsIgnoreCase(uri.getScheme())) {
            // 如果是file类型的Uri，直接获取图片路径即可
            imagePath = uri.getPath();
        }
        System.out.println("imagePath路径："+imagePath);
        displayImage(imagePath); // 根据图片路径显示图片
    }

    private void handleImageBeforeKitKat(Intent data) {
        Uri uri = data.getData();
        String imagePath = getImagePath(uri, null);
        displayImage(imagePath);
    }

    private String getImagePath(Uri uri, String selection) {
        String path = null;
        // 通过Uri和selection来获取真实的图片路径
        Cursor cursor = getContentResolver().query(uri, null, selection, null, null);
        if (cursor != null) {
            if (cursor.moveToFirst()) {
                path = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA));
            }
            cursor.close();
        }
        return path;
    }

    private void displayImage(String imagePath) {
        if (imagePath != null) {
            Bitmap bitmap = BitmapFactory.decodeFile(imagePath);
            picture.setImageBitmap(bitmap);
        } else {
            Toast.makeText(this, "failed to get image", Toast.LENGTH_SHORT).show();
        }
    }


    //TODO
    public void upload(View view) {
        new Thread(new Runnable() {
            @Override
            public void run() {
//                File file = new File("/storage/emulated/0/Tencent/QQ_Images/-1a45eb02c89a3895.jpg");
                File file = new File(imagePath);
                System.out.println("测试返回结果imagePath:"+imagePath);
                OkHttpClient okHttpClient = new OkHttpClient();

                RequestBody body = new MultipartBody.Builder()
                        .setType(MultipartBody.FORM)
                        .addFormDataPart("file", file.getName(), MultipartBody.create(MediaType.parse("multipart/form-data"), new File(imagePath)))
                        .build();

                String url = "http://ip:8001/server/fileoss";
                Request request = new Request.Builder()
                        .url(url)
                        .post(body)
                        .build();

                okHttpClient.newCall(request).enqueue(new Callback() {
                    @Override
                    public void onFailure(Call call, IOException e) {

                    }
                    @Override
                    public void onResponse(Call call, Response response) throws IOException {
                        String result = response.body().string();
                        Gson gson = new GsonBuilder().create();
                        ResultGson resultGson = gson.fromJson(result, ResultGson.class);
                        System.out.println("测试返回结果："+result);
                        System.out.println("测试返回结果："+resultGson);
                        System.out.println("测试返回结果："+resultGson.getData());
                        System.out.println("测试返回结果："+resultGson.getCode());
                        System.out.println("测试返回结果："+resultGson.getData().get("url"));
                    }
                });
            }
        }).start();
    }
}

这里我先打开相册。然后选中照片，并在imageView里显示出来，然后再在点击上传，通过后端的接口，将照片上传至服务器中。日志显示成功！

4、阿里云OSS服务

打开阿里云的OSS服务，发现存储成功。

二、后端搭建

这里新建一个Springboot项目。这里可以去参照《Android使用OKhttp3实现登录注册功能+springboot搭建后端》，我也是在这个基础上继续搭建的。主要修改以下这些代码。

1、application.properties

# 服务端口
server.port=8001
# 服务名
spring.application.name=heartrate

# 环境设置：dev、test、prod
spring.profiles.active=dev

# mysql数据库连接
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://ip:3310/heartrate?serverTimezone=GMT%2B8&useSSL=false
spring.datasource.username=root
spring.datasource.password=123456


#返回json的全局时间格式
spring.jackson.date-format=yyyy-MM-dd HH:mm:ss
spring.jackson.time-zone=GMT+8

#mybatis日志//要使用logback日志，就需要注释掉
mybatis-plus.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl

#配置mapper xml文件的路径
mybatis-plus.mapper-locations=classpath:com/atguigu/eduservice/mapper/xml/*.xml


#阿里云 OSS
#不同的服务器，地址不同
aliyun.oss.file.endpoint=oss-cn-beijing.aliyuncs.com
aliyun.oss.file.keyid=keyid
aliyun.oss.file.keysecret=keysecret
#bucket可以在控制台创建，也可以使用java代码创建
aliyun.oss.file.bucketname=ahuwhq

这里换成自己阿里云申请到的keyid和keysecret

2、OssService

public interface OssService {
    //上传头像到oss
    String uploadFileAvatar(MultipartFile file);
}

3、OssServiceImpl

@Service
public class OssServiceImpl implements OssService {


    //上传头像到oss
    @Override
    public String uploadFileAvatar(MultipartFile file) {
        // 工具类获取值
        String endpoint = ConstantPropertiesUtils.END_POINT;
        String accessKeyId = ConstantPropertiesUtils.ACCESS_KEY_ID;
        String accessKeySecret = ConstantPropertiesUtils.ACCESS_KEY_SECRET;
        String bucketName = ConstantPropertiesUtils.BUCKET_NAME;

        try {
            // 创建OSS实例。
            OSS ossClient = new OSSClientBuilder().build(endpoint, accessKeyId, accessKeySecret);

            //获取上传文件输入流
            InputStream inputStream = file.getInputStream();
            System.out.println("文件输入流："+file.getInputStream());
            System.out.println("文件输入流："+file.getContentType());
            //获取文件名称
            String fileName = file.getOriginalFilename();
            System.out.println("文件名称："+file.getOriginalFilename());


            //1 在文件名称里面添加随机唯一的值
            String uuid = UUID.randomUUID().toString().replaceAll("-","");
            // yuy76t5rew01.jpg
            fileName = uuid+fileName;

            //2 把文件按照日期进行分类
            //获取当前日期
            //   2019/11/12
            String datePath = new DateTime().toString("yyyy/MM/dd");
            //拼接
            //  2019/11/12/ewtqr313401.jpg
            fileName = datePath+"/"+fileName;

            //调用oss方法实现上传
            //第一个参数  Bucket名称
            //第二个参数  上传到oss文件路径和文件名称   aa/bb/1.jpg
            //第三个参数  上传文件输入流
            ossClient.putObject(bucketName,fileName , inputStream);

            // 关闭OSSClient。
            ossClient.shutdown();

            //把上传之后文件路径返回
            //需要把上传到阿里云oss路径手动拼接出来
            //  https://edu-guli-1010.oss-cn-beijing.aliyuncs.com/01.jpg
            String url = "https://"+bucketName+"."+endpoint+"/"+fileName;
            return url;
        }catch(Exception e) {
            e.printStackTrace();
            return null;
        }
    }
}

4、ConstantPropertiesUtils.java

/**
 * 常量类，读取配置文件application.properties中的配置
 */
@Component
//@PropertySource("classpath:application.properties")
public class ConstantPropertiesUtils implements InitializingBean {
    @Value("${aliyun.oss.file.endpoint}")
    private String endpoint;
    @Value("${aliyun.oss.file.keyid}")
    private String keyId;
    @Value("${aliyun.oss.file.keysecret}")
    private String keySecret;
    @Value("${aliyun.oss.file.bucketname}")
    private String bucketName;
    public static String END_POINT;
    public static String ACCESS_KEY_ID;
    public static String ACCESS_KEY_SECRET;
    public static String BUCKET_NAME;
    @Override
    public void afterPropertiesSet() throws Exception {
        END_POINT = endpoint;
        ACCESS_KEY_ID = keyId;
        ACCESS_KEY_SECRET = keySecret;
        BUCKET_NAME = bucketName;
    }
}

5、OssController.java

@RestController
@RequestMapping("/server/fileoss")
//@CrossOrigin
public class OssController {
    @Autowired
    private OssService ossService;
    //上传头像的方法
    @PostMapping
    public R uploadOssFile(MultipartFile file) {
        //获取上传文件  MultipartFile
        //返回上传到oss的路径
        String url = ossService.uploadFileAvatar(file);
        return R.ok().data("url",url);
    }
}

6、MainApplication.java

@SpringBootApplication
@ComponentScan(basePackages = {"com.message"})
public class MainApplication {
    public static void main(String[] args) {
        SpringApplication.run(MainApplication.class, args);
    }
}

这样就可以启动这个项目了。打开swagger进行测试

，然后使用maven打包，上传至服务器就可以了。