导出联系人到excel表格

/**此处导出的是电话联系人*/
1、导入poijar包；
2、可能会报出异常：
如何解决error：execution failed for task app：transformclasseswithjarmerging

解决方法:

defaultConfig {
        multiDexEnabled true
}

3代码如下

public class backUpUtils {

    public interface  backUpCallBack{
        public void onCallBack(int progress);
        public void befor(int count);
    }

    public static boolean backUp(Context context, backUpCallBack callBack){
        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {//判断是否有sdk
            File file=new File(Environment.getExternalStorageDirectory(),"workbook.xls");//建立sms文件
            ContentResolver resolver = context.getContentResolver();
            //Uri uri = Uri.parse("content://sms/");
            Cursor cursor = resolver.query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI,null, null, null, null);//遍历数据表
           int count=cursor.getCount();
            callBack.befor(count);
            int progress=0;
            try {
                OutputStream os=new FileOutputStream(file);
//                XmlSerializer serializer= Xml.newSerializer();//序列化数据
//                serializer.setOutput(os,"utf-8");
//                serializer.startDocument("utf-8",true);
//                serializer.startTag(null,"contact");
                HSSFWorkbook wb=new HSSFWorkbook();
                HSSFSheet sheet=wb.createSheet("new sheet");
                wb.setSheetName(0,"数据库数据");
                HSSFRow row=sheet.createRow((short)0);
                sheet.createFreezePane(0,1);
                cteateCell(wb,row,(short)0,"联系人");
                cteateCell(wb,row,(short)1,"电话号码");
                int i=0;
                while (cursor.moveToNext()) {
                    String name=cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));
                    String number=cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
                    System.out.println("联系人:"+name+">>>>>>>>"+"电话号码"+number);
                    i++;
                    HSSFRow row2=sheet.createRow((short)i);
                    cteateCell(wb,row2,(short)0,name);
                    cteateCell(wb,row2,(short)1,number);
                    progress++;
                   callBack.onCallBack(progress);
                    SystemClock.sleep(200);
                }
                wb.write(os);//写入流
                os.flush();
                os.close();
                return true;
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
     return false;
    }
    private static void cteateCell(HSSFWorkbook wb, HSSFRow row, short col, String val)
    {
        HSSFCell cell=row.createCell(col);
        cell.setCellValue(val);
        HSSFCellStyle cellstyle=wb.createCellStyle();
        cellstyle.setAlignment(HSSFCellStyle.ALIGN_CENTER_SELECTION);
        cell.setCellStyle(cellstyle);
    }

}