Socket来实现大文件的断点续传

实现流程图：

代码示例：

客户端(Android端)实现示例：

1.因为断点续传，我们需要保存上传的进度，我们需要用到数据库，这里我们定义一个数据库 管理类：

public class DBOpenHelper extends SQLiteOpenHelper {

    public DBOpenHelper(Context context) {
        super(context, "jay.db", null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE IF NOT EXISTS uploadlog (_id integer primary key autoincrement, path varchar(20), sourceid varchar(20))");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }
}

2.然后是数据库操作类：UploadHelper.java：

public class UploadHelper {
    private DBOpenHelper dbOpenHelper;

    public UploadHelper(Context context) {
        dbOpenHelper = new DBOpenHelper(context);
    }

    public String getBindId(File file) {
        SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
        Cursor cursor = db.rawQuery("select sourceid from uploadlog where path=?", new String[]{file.getAbsolutePath()});
        if (cursor.moveToFirst()) {
            return cursor.getString(0);
        }
        return null;
    }

    public void save(String sourceid, File file) {
        SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
        db.execSQL("insert into uploadlog(path,sourceid) values(?,?)",
                new Object[]{file.getAbsolutePath(), sourceid});
    }

    public void delete(File file) {
        SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
        db.execSQL("delete from uploadlog where path=?", new Object[]{file.getAbsolutePath()});
    }
}

3.最后就是我们的MainActivity.java了：

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    private EditText edit_fname;
    private Button btn_upload;
    private Button btn_stop;
    private ProgressBar pgbar;
    private TextView txt_result;

    private UploadHelper upHelper;
    private boolean flag = true;


    private Handler handler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            pgbar.setProgress(msg.getData().getInt("length"));
            float num = (float) pgbar.getProgress() / (float) pgbar.getMax();
            int result = (int) (num * 100);
            txt_result.setText(result + "%");
            if (pgbar.getProgress() == pgbar.getMax()) {
                Toast.makeText(MainActivity.this, "上传成功", Toast.LENGTH_SHORT).show();
            }
        }
    };

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        bindViews();
        upHelper = new UploadHelper(this);
    }

    private void bindViews() {
        edit_fname = (EditText) findViewById(R.id.edit_fname);
        btn_upload = (Button) findViewById(R.id.btn_upload);
        btn_stop = (Button) findViewById(R.id.btn_stop);
        pgbar = (ProgressBar) findViewById(R.id.pgbar);
        txt_result = (TextView) findViewById(R.id.txt_result);

        btn_upload.setOnClickListener(this);
        btn_stop.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.btn_upload:
                String filename = edit_fname.getText().toString();
                flag = true;
                if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
                    File file = new File(Environment.getExternalStorageDirectory(), filename);
                    if (file.exists()) {
                        pgbar.setMax((int) file.length());
                        uploadFile(file);
                    } else {
                        Toast.makeText(MainActivity.this, "文件并不存在~", Toast.LENGTH_SHORT).show();
                    }
                } else {
                    Toast.makeText(MainActivity.this, "SD卡不存在或者不可用", Toast.LENGTH_SHORT).show();
                }
                break;
            case R.id.btn_stop:
                flag = false;
                break;
        }
    }

    private void uploadFile(final File file) {
        new Thread(new Runnable() {
            public void run() {
                try {
                    String sourceid = upHelper.getBindId(file);
                    Socket socket = new Socket("172.16.2.54", 12345);
                    OutputStream outStream = socket.getOutputStream();
                    String head = "Content-Length=" + file.length() + ";filename=" + file.getName()
                            + ";sourceid=" + (sourceid != null ? sourceid : "") + "\r\n";
                    outStream.write(head.getBytes());

                    PushbackInputStream inStream = new PushbackInputStream(socket.getInputStream());
                    String response = StreamTool.readLine(inStream);
                    String[] items = response.split(";");
                    String responseSourceid = items[0].substring(items[0].indexOf("=") + 1);
                    String position = items[1].substring(items[1].indexOf("=") + 1);
                    if (sourceid == null) {//如果是第一次上传文件，在数据库中不存在该文件所绑定的资源id
                        upHelper.save(responseSourceid, file);
                    }
                    RandomAccessFile fileOutStream = new RandomAccessFile(file, "r");
                    fileOutStream.seek(Integer.valueOf(position));
                    byte[] buffer = new byte[1024];
                    int len = -1;
                    int length = Integer.valueOf(position);
                    while (flag && (len = fileOutStream.read(buffer)) != -1) {
                        outStream.write(buffer, 0, len);
                        length += len;//累加已经上传的数据长度
                        Message msg = new Message();
                        msg.getData().putInt("length", length);
                        handler.sendMessage(msg);
                    }
                    if (length == file.length()) upHelper.delete(file);
                    fileOutStream.close();
                    outStream.close();
                    inStream.close();
                    socket.close();
                } catch (Exception e) {
                    Toast.makeText(MainActivity.this, "上传异常~", Toast.LENGTH_SHORT).show();
                }
            }
        }).start();
    }

}