Android 通過圖庫或相機加載圖片，并將圖片傳到服務器上-有解無憂

–添加權限

    <uses permissionandroid:name="com.android.launcher.permission.READ_SETTINGS" />
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.CAMERA" />

–使用相機獲得圖片
–1

  private  Uri ImageUri=null;

   		創建一個File物件，用于儲存拍照后的圖片，并把圖片命名為outputImage.jpg,
   		并把它手機Sd卡的應用快取的位置(就是指Sd卡中專門用于存放當前應用快取資料
   		的位置，呼叫getExternalCacheDir()方法可以得到這個目錄，)
   		如果我們使用這種應用快取目錄來存放圖片，就可以跳過運行時權限的處理，
   		(Android6.系統開始，讀寫Sd卡被列為了危險權限，需要進行運行時權限的處理)，
   		
		 File outputImage=new File(getExternalCacheDir(),"outputImage.jpg");
        try {
            if (outputImage.exists()){
                outputImage.delete();
            }
            outputImage.createNewFile();
        } catch (IOException e) {
            e.printStackTrace();
        }
        這里進行了一個判斷，如果運行設備版型低于Android7.0，就呼叫Uri的formFile()方法，
        否則，就呼叫FileProvider的getUriForFile()方法將File物件轉為一個封裝過的Uri，
        if (Build.VERSION.SDK_INT>=24){
            ImageUri= FileProvider.getUriForFile(CallThePolice.this,
                    "com.example.car.fileprovider",outputImage);
        }else {
            ImageUri=Uri.fromFile(outputImage);
        }
        //啟動相機程式
        Intent intent=new Intent("android.media.action.IMAGE_CAPTURE");
        intent.putExtra(MediaStore.EXTRA_OUTPUT,ImageUri);
        startActivityForResult(intent,2);

–2
在AndroidManifest.xml中內容提供器進行注冊，

   <provider
            android:authorities="com.example.car.fileprovider"
            android:name="android.support.v4.content.FileProvider"
            android:exported="false"
            android:grantUriPermissions="true">
            <meta-data
                android:name="android.support.FILE_PROVIDER_PATHS"
                android:resource="@xml/file_paths"/>
        </provider>

其中android:authorities 屬性必須要和剛才FileProvider,getUriForFile()方法的第二個引數一致，另外，
這里還在<provider>標簽的內部使用<meta-data>來指定Uri的共享路徑，參考一個@xml/file_paths資源，

–3
在res的xml目錄下創建file_path.xml

<?xml version="1.0" encoding="utf-8"?>
<paths>
    <external-path  name="camera_photos"  path="" />
</paths>

其中，external-path就是用來指定Uri共享的，name屬性可以隨便改，path屬性的值表示共享的具體路徑，這里設空表示將整個卡進行共享，

最后，為了兼容Android4.4以下的老版本，在AndroidManifest.xml下宣告，訪問Sd卡的權限，

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

–2呼叫圖庫獲得圖片

  Intent intent = new Intent();
  intent.setType("image/*");//選圖片
  intent.putExtra(Intent.EXTRA_ALLOW_MULTIPLE, true);//選擇多張圖片
  intent.setAction(Intent.ACTION_GET_CONTENT);
   //Intent.createChooser(),創建應用選擇器,系統會根據條件進行過濾            
  startActivityForResult(Intent.createChooser(intent, "select_picture"), 1);

–3處理相機和圖庫中來的圖片

–1首先創建一個RecyclerView的Adapter

public class PictureAdapter extends RecyclerView.Adapter<PictureAdapter.MyViewHolder> {

    private Context mContext;
    private List<Bitmap> mDatas;
    private LayoutInflater mInflater;
    public PictureAdapter(Context context, List<Bitmap> datas, ) {
        mContext = context;
        mDatas   = datas;
        mInflater = LayoutInflater.from(context);
    }
    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View itemView = mInflater.inflate(R.layout.load_item_pic, parent, false);
        final MyViewHolder holder=new MyViewHolder(itemView);

        return holder;
    }
    @Override
    public void onBindViewHolder(MyViewHolder holder, int position) { 
            Bitmap bitmap= mDatas.get(position);
            holder.mIvDisPlayItemPhoto.setImageBitmap(bitmap);
    }

    @Override
    public int getItemCount() {
        return mDatas.size();
    }
    public class MyViewHolder extends RecyclerView.ViewHolder {
        @Bind(R.id.ivPic)
        ImageView mIvDisPlayItemPhoto=itemView.findViewById(R.id.ivPic);
        public MyViewHolder(View itemView) {
            super(itemView);
            ButterKnife.bind(this, itemView);
        }
    }
 }

–2在onActivityResult中處理相機和圖庫中來的資料

private  List<Bitmap> bitmap = new ArrayList<>();//用來儲存拍照和圖庫中來的圖片
private  List<Uri> URI = new ArrayList<>();//用來記錄要上傳照片的路徑，上傳到服務器要用到
@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        int i = 0;
        recyclerView = findViewById(R.id.picture);
        LinearLayoutManager ms = new LinearLayoutManager(this);
        ms.setOrientation(LinearLayoutManager.HORIZONTAL);//將recyclerView的布局設定為橫向
        switch (requestCode) {
      	  case 1://處理圖庫回傳的資料
       		 if (data != null) {
       			 for (i = 0; i < data.getClipData().getItemCount(),i++) {
       			 URI.add(data.getClipData().getItemAt(i).getUri());
       				 try {
            				bitmap.add(BitmapFactory.decodeStream(getContentResolver().openInputStream(data.getClipData().getItemAt(i).getUri()), null, null));
       					 } catch (FileNotFoundException e) {
       						 e.printStackTrace();
       			 }
     		   pictureAdapter = new PictureAdapter(getApplicationContext(), bitmap);
      		  recyclerView.setLayoutManager(ms);
       		  recyclerView.setAdapter(pictureAdapter);
       		 } else {
       			 Toast.makeText(CallThePolice.this,"您未選擇圖片",Toast.LENGTH_SHORT).show();
        	}
        		break;
        case 2://處理相機回傳的資料
        if(ImageUri==null){
       		 Toast.makeText(CallThePolice.this,"您未選擇圖片",Toast.LENGTH_SHORT).show();
        } else{
        try {
        	 URI.add(ImageUri);
        	 bitmap.add(BitmapFactory.decodeStream(getContentResolver().openInputStream(ImageUri)));
        } catch (FileNotFoundException e) {
      		  e.printStackTrace();
        }
        	pictureAdapter = new PictureAdapter(getApplicationContext(), bitmap);
        	recyclerView.setLayoutManager(ms);
        	recyclerView.setAdapter(pictureAdapter);
        	}
       		 break;
       	 }
        }

–4將圖片上傳到服務器

–1先將圖片的Uri轉為真實路徑

public String getRealPathFromURI(Uri contentUri) {
        String res = null;
        String[] proj = { MediaStore.Images.Media.DATA };
        Cursor cursor = getContentResolver().query(contentUri, proj, null, null, null);
        if(cursor.moveToFirst()){;
            int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
            res = cursor.getString(column_index);
        }
        cursor.close();
        return res;
    }

–2上傳到服務器(用Okhttp)

    public void Upload() {

       MultipartBody.Builder builder=new MultipartBody.Builder();
        OkHttpClient okHttpClient=new OkHttpClient();
        if(URI!=null && URI.size()!=0){
            for(Uri uri:URI){
                File file=new File(getRealPathFromURI(uri));
                builder.addFormDataPart("file",file.getName(),RequestBody.create(MediaType.parse("image/jpg"),file));
            }
            MultipartBody multipartBody=builder.build();
           final Request request=new Request.Builder()
                   .url( "http://192.168.123.129:8080/ServerForAndroid/Upload")
                    .post(multipartBody)
                   .build();
            okHttpClient.newCall(request).enqueue(new Callback() {
               @Override
               public void onFailure(@NotNull Call call, @NotNull IOException e) {

                   if(e.getCause().equals(SocketTimeoutException.class))//如果超時
                   {
                       progressBar.setVisibility(View.INVISIBLE);
//                       Toast.makeText(CallThePolice.this,"上傳失敗",Toast.LENGTH_SHORT).show();
                   }else{
                       progressBar.setVisibility(View.INVISIBLE);
                       Looper.prepare();
                       Toast.makeText(CallThePolice.this,"上傳失敗",Toast.LENGTH_SHORT).show();
                       Looper.loop();
                   }
               }

               @Override
               public void onResponse(@NotNull Call call, @NotNull Response response) throws IOException {
                    progressBar.setVisibility(View.INVISIBLE);
                    Looper.prepare();
                    Toast.makeText(CallThePolice.this,"上傳成功",Toast.LENGTH_SHORT).show();
                    Looper.loop();
               }

           });
        }
    }

–5服務器servlet處理邏輯

–1將必要的jar包
在這里插入圖片描述
這兩個包必須要匯入！（可以用maven下這兩個包）

–2代碼

package service;

import java.util.ArrayList;
import java.util.List; 
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

public class Upload extends HttpServlet {	
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		DiskFileItemFactory factory=new DiskFileItemFactory();
		System.out.print("in");
		String path="D:\\test";
		factory.setRepository(new File(path));
		factory.setSizeThreshold(1024*1024*4);
		ServletFileUpload upload=new ServletFileUpload(factory);
		try {
			List<FileItem> list=(ArrayList<FileItem>)upload.parseRequest(request);
			for(FileItem item:list){
				if(!item.isFormField()){		
					String value = item.getName();  
                    //取到最后一個反斜杠，  
                    int start = value.lastIndexOf("\\");  
                    //截取上傳檔案的 字串名字，+1是去掉反斜杠，  
                    String filename = value.substring(start+1);  
                    PrintWriter out=response.getWriter(); 
                    out.format("sj", "成功");
                    /*直接寫到檔案中， */
                    item.write(new File(path,filename)); 
				}
			}		
		} catch (FileUploadException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			System.out.print(e.toString());
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			System.out.print(e.toString());
		}	
	}
}

–3圖片顯示

如果上傳成功的話，會在D盤的test目錄下，顯示圖片，
在這里插入圖片描述

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