http断点续传简单实现（java)

/* { 1+Cw?1d  
**SiteFileFetch.java J[
e}  
*/ $|4cJ#;^L  
package NetFox; !oZQ2z~  
import java.io.*; %04:z77  
import java.net.*; i{o#3  
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public class SiteFileFetch extends Thread { ^cYStMjpy  
h&)fu{   
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SiteInfoBean siteInfoBean = null; //文件信息Bean r5t;'eCea  
long[] nStartPos; //开始位置 _*O7l  
long[] nEndPos; //结束位置 =nJ{$%L\x,  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 <+V-k|  
long nFileLength; //文件长度 ?qju DD  
boolean bFirst = true; //是否第一次取文件 d{er|$E?  
boolean bStop = false; //停止标志 B4`2.yRis  
File tmpFile; //文件下载的临时信息 qBT_! )h   
DataOutputStream output; //输出到文件的输出流 >vUB%OLyP  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） #v{Y=$L  
public SiteFileFetch(SiteInfoBean bean) throws IOException aXMv(e+  
{ ZU=,f'bU  
siteInfoBean = bean; r eGm>  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^'m\D;
 
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?q\FLb%"7  
if(tmpFile.exists ()) %dEB/[  
{ EJ1Bq>u7  
bFirst = false; ARPKzF`Wq  
read_nPos(); 10mK}HT>4B  
} 7$!yfMttu  
else z8IPhE@  
{ ^;.T}c%N  
nStartPos = new long[bean.getNSplitter()]; 3pB}2]  
nEndPos = new long[bean.getNSplitter()]; 8EOh0gk7  
} n'THe|:I  
N? M   
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} G3G/xC"  
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public void run() |~z3U>  
{ *RBV'b  
//获得文件长度 (B@X[
~  
//分割文件
)T9;6R$b  
//实例FileSplitterFetch bG"HD?A_  
//启动FileSplitterFetch线程 "jT#bIm  
//等待子线程返回 1@xP(XS  
try{ Q8p=!K  
if(bFirst) m#JI!_~!  
{ g6WPPpqus  
nFileLength = getFileSize(); ny)]GvxI  
if(nFileLength == -1) uKv&7p@|_)  
{ $*k)|4
 
System.err.println("File Length is not known!"); c7\VTYT  
} S.{fDcM  
else if(nFileLength == -2) xOythvO  
{ +IrZ ;&oy  
System.err.println("File is not access!"); 6Opa{]  
} Av o|v>  
else P|N2R5(>T  
{
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for(int i=0;i<nStartPos.length;i++) e&0K;yU  
{ $xT1 1 ^  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); D|l,08n"?  
} r4u z} jl{  
for(int i=0;i<nEndPos.length-1;i++) /be=u@KV  
{ n#4Gv|{XMD  
nEndPos = nStartPos[i+1]; P^pFqUL7#  
} @xS]!1-  
nEndPos[nEndPos.length-1] = nFileLength; 9t?L\
  
} Vo\H<_=
G  
} >)NQH9'1  
eX"''PA  
}k7_'p&yk  
//启动子线程 k^%2_H  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; bHE7yv [  
for(int i=0;i<nStartPos.length;i++) \7Qb229?  
{ 'f+NW&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )s)_XL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), NgVR,G|1  
nStartPos,nEndPos,i); R(G\wqHUT3  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _1aGtX|W  
fileSplitterFetch.start(); ?sXG17~Bm  
} =\Iu$2r`
 
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), z<B CLP  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); a[sKE?  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", hd2'AlB  
nEndPos = " + nFileLength); yzR=A%V8A  
// fileSplitterFetch[nPos.length-1].start(); %D`o  
yS!(Ap  
8O7Yv<  
//等待子线程结束 @E%DP9.I  
//int count = 0; L[y Pjw:0  
//是否结束while循环 -R0/o7  
boolean breakWhile = false; zT[6eZ8m  
w^HjZV  
CE ~@}`  
while(!bStop) ^2S# Uk  
{ +BL{@,zr  
write_nPos(); $ J1f.YE  
Utility.sleep(500); -:<lkq&/  
breakWhile = true; [|RjHGf  
)K;]y-Us[  
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for(int i=0;i<nStartPos.length;i++) irKI
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{ k_ Y~;P@  
if(!fileSplitterFetch.bDownOver) Dz;HAyPj  
{  \S4SI  
breakWhile = false; mrM4RoO  
break; Qhn;`9+L  
} fvqd'2 t  
} T2=HG Z  
if(breakWhile) s_[VHPN  
break; DMn4ll|  
$4m*kQ  
$SY]fNJQ  
//count++; I4t*?  
//if(count>4) @MbVWiv  
// siteStop(); fThgK;Qy'U  
} h/)_) r.x  
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System.err.println("文件下载结束！"); G$bJ+  
} !yJICjXj  
catch(Exception e){e.printStackTrace ();} wRvb8F0  
} 3@<zg1.9-  
0N;%2=2_E  
-SCM:j%h  
//获得文件长度 ~F!,PM/  
public long getFileSize() H:QhrL+7_  
{ V
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int nFileLength = -1; $_Nf-:D*  
try{ w0lT%CPx  
URL url = new URL(siteInfoBean.getSSiteURL()); fCw*$:O  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;11x"S  
httpConnection.setRequestProperty("User-Agent","NetFox"); ru9zTZZD  
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r!GW=u'  
int responseCode=httpConnection.getResponseCode(); N|usFqCNk^  
if(responseCode>=400) "_1)CDqP  
{ nw6pV%  
processErrorCode(responseCode); =9wy/c$  
return -2; //-2 represent access is error WsGths+[  
} %,P>%'0  
*ZrSiIPP  
w@-M{?R  
String sHeader; Fhf<T`  
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mtAE  
for(int i=1;;i++) ?C-Towo=i  
{ 78 f$6J q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); kz}R[7  
//Utility.log(in.readLine()); U7h(`b  
sHeader=httpConnection.getHeaderFieldKey(i); B1!kn}KlL{  
if(sHeader!=null) x;s0j"`Jb  
{ lLhL`C!  
if(sHeader.equals("Content-Length")) Qzv
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{ oUZoj2G1  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2JGL;U$  
break; EgjR^A1W2  
} XvTCK>1  
} hX:"QXx  
else \ 0W!4
D  
break; zUJZ`seF  
} c9"r6j2m5  
} ;&b.T}Nf06  
catch(IOException e){e.printStackTrace ();} Q\ppfc{,  
catch(Exception e){e.printStackTrace ();} OHv!  
^D%Za'  
baV>N[F&  
Utility.log(nFileLength); W/$Zvl  
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return nFileLength;
=FP0\cQ.  
} 4GdX/6C.  
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e'%v1-&sP  
//保存下载信息（文件指针位置） "qz3u`[o  
private void write_nPos() rwLAW"0Qz  
{ ZBT1Y.qA  
try{ 46@{5)Tq  
output = new DataOutputStream(new FileOutputStream(tmpFile)); : 18KR*;p  
output.writeInt(nStartPos.length); !9Z r;K~\  
for(int i=0;i<nStartPos.length;i++) DyJ.BQdk)  
{ r0;:t  
// output.writeLong(nPos); -a,-J]d0+  
output.writeLong(fileSplitterFetch.nStartPos); <EO$]>;0  
output.writeLong(fileSplitterFetch.nEndPos); dO> VwP  
} '7^M{y/dU  
output.close(); RD7^&  
} sUJ%x#u}Fk  
catch(IOException e){e.printStackTrace ();} )SF}2?7e  
catch(Exception e){e.printStackTrace ();} `{k"8#4:qA  
} x+8_4>,>Y7  
afBE{  
Ysq'2  
//读取保存的下载信息（文件指针位置） }o4N<%/+  
private void read_nPos() v{zMO:3  
{ }/tf>?c  
try{ X|f7K  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ]V l]XT$Um  
int nCount = input.readInt(); vX0f,y  
nStartPos = new long[nCount];  xw^R@H  
nEndPos = new long[nCount]; zi R5:d3   
for(int i=0;i<nStartPos.length;i++) #6Fez`A  
{ Un`^jw#_  
nStartPos = input.readLong(); BS Iy+  
nEndPos = input.readLong(); >(uZtYM\j  
} c\B|KhDk  
input.close(); F'jWV5"*  
} "k*PA\U  
catch(IOException e){e.printStackTrace ();} $vC1 K5sLk  
catch(Exception e){e.printStackTrace ();} MYJg8 '[j  
} /Jf.y*;  
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{!6/x9>  
private void processErrorCode(int nErrorCode)  ]#7zk9  
{ fVb-$  
System.err.println("Error Code : " + nErrorCode); kB?al#`  
} -F'b8:m  
I2nF-JzD2a  
6"Bic rY  
//停止文件下载 R\o<7g-|  
public void siteStop() yFDv6yJ.  
{ m_?d=o  
bStop = true; 06$!R/K  
for(int i=0;i<nStartPos.length;i++)
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fileSplitterFetch.splitterStop(); )*4fzo  
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} eF[63zx5*  
} TIp:FW[  
//负责部分文件的抓取 -@T/b$]'n  
**FileSplitterFetch.java zSo)k~&[3  
*/ Q+4Xs.#  
package NetFox; T,| 1g6  
X[f=h=|  
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import java.io.*; UnI48Y  
import java.net.*; 7AYd!n&S  
0-~\ W(  
X]\ \,  
public class FileSplitterFetch extends Thread { T&Lb<'f  
^i:`ZfA#
 
(aD_zG=k5  
String sURL; //File URL !\&;h  
long nStartPos; //File Snippet Start Position z9aY]lHY  
long nEndPos; //File Snippet End Position K~@Mg1R  
int nThreadID; //Thread's ID A&nU]R8S  
boolean bDownOver = false; //Downing is over gy&[?m6M=  
boolean bStop = false; //Stop identical W5SJ^,d)J  
FileAccessI fileAccessI = null; //File Access interface &f&z_WU  
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<.Nx[!'~&d  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException u_ABt?'  
{ H54R8O$  
this.sURL = sURL; &|/| ''A)  
this.nStartPos = nStart; 5 ~TdD6}  
this.nEndPos = nEnd; [Q=dCX9%  
nThreadID = id; 'fW6 .0fXa  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 bV ZMW/w  
} zN  [2YJ$  
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,"B+r6}EF  
public void run() Iu$K i  
{ =i~}84>  
while(nStartPos < nEndPos && !bStop) -jMJAYjV  
{ +nJUFc  
lo[.&GD  
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try{ )_U<7"~0l  
URL url = new URL(sURL); >nzdnF_&zW  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); cReB~wk  
httpConnection.setRequestProperty("User-Agent","NetFox"); tKpmm`2  
String sProperty = "bytes="+nStartPos+"-"; Nm|!#(L  
httpConnection.setRequestProperty("RANGE",sProperty); `ho1nY$)CE  
Utility.log(sProperty); O%FPS=  
S#+h$UVh  
Th=eNL]  
InputStream input = httpConnection.getInputStream(); lV%N  
//logResponseHead(httpConnection); L'u\w  
2Lx3=k  
=jN*P?  
byte[] b = new byte[1024]; }Hn/I,/  
int nRead; k{'0[,mx#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^MVkZ{gtre  
{ 9/nn)soC3  
nStartPos += fileAccessI.write(b,0,nRead); 0:+WO%z  
//if(nThreadID == 1) {?yr'*  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Hla0 5N' 4  
} V,$0p1?J  
^Vpq$'!  
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0  
Utility.log("Thread " + nThreadID + " is over!"); b#X^=n2  
bDownOver = true; >Q(3*d >  
//nPos = fileAccessI.write (b,0,nRead); ?mwD*LN3o  
} )b:7-}d  
catch(Exception e){e.printStackTrace ();} Zl*X?5u  
} }mAa}{_  
} rb|U;)C  
[i]Ub0Dh7  
SLh(9%S;  
//打印回应的头信息 /kfgx{jZ  
public void logResponseHead(HttpURLConnection con) ['T:ea6B  
{ ;aw=MV  
for(int i=1;;i++) _'(,  
{ \_lod kf  
String header=con.getHeaderFieldKey(i); Rj4|Q:XG  
if(header!=null) nJo`B4'U  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); yxH ( c  
Utility.log(header+" : "+con.getHeaderField(header)); ]wtb-PC  
else QDu2?EYZq  
break; o#skR4lwe  
} Rb.SY{}C  
} uXKERzg  
Ry'= ke  
_A=$oVe  
public void splitterStop() ~m$Y$,uH  
{ )gMG#>up@  
bStop = true; RRI"d~~F6  
} CO`_^7o9(  
t]YC"%[S  
0|a(]a}V*j  
} Y*14v~\'  
/K(o]J0F  
THS.GvT9[  
/* |cR;{Z8?_  
**FileAccess.java ` eXaT8  
*//文件访问(定位，写) 'nwx9]q  
package NetFox; ~x|F)~:0=  
import java.io.*; uH(f$A  
s{$(*_  
uB]b}
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public class FileAccessI implements Serializable{ VSSu&Q  
Ba!J"b]  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 *3?'4"B{8  
RandomAccessFile oSavedFile; Dp':oJC
  
long nPos; 2n
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!Ze5)g%H  
4 XAQVq5  
public FileAccessI() throws IOException sNLs\4v  
{ aXoVy&x=  
this("",0); jJ5W>Q1mK$  
} K|Di1)7=/  
v+X)Qmzf~  
6#HK'7ClL  
public FileAccessI(String sName,long nPos) throws IOException m_)FC-/pSl  
{ xjVS  
oSavedFile = new RandomAccessFile(sName,"rw"); yI"6Da6|y  
this.nPos = nPos; 1#ft#-g}
 
oSavedFile.seek(nPos); @9lUSk^9  
} P9vA7[  
/%;mqrdk  
hX=A)73(  
public synchronized int write(byte[] b,int nStart,int nLen) d&+h}O  
{ cj1cZ-  
int n = -1; ekWePL;rR2  
try{ f>N!wgo[  
oSavedFile.write(b,nStart,nLen); "*Tb" 'O  
n = nLen; vuoQz\  
} {\:{[{qF  
catch(IOException e) E/%9jDTQ  
{ H
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e.printStackTrace (); Y4v|ko`l%  
} OR;uqV@  
o}* hY"&  
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return n; ;JayoJ  
} FgB&b  
l=v4Fa0^jF  
}Nf%n@  
} H{=21\a\  
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<1t*I!e_  
/* 0Nnsjh  
**SiteInfoBean.java 1q,{0s_kp  
*/ 23DiW#o'  
package NetFox; OUhqMVX9C  
Kq;8=xP[  
_Nqt21sL  
public class SiteInfoBean { /K.!sQ$  
"-+\R}q$  
4#:W.]U8  
private String sSiteURL; //Site's URL ;{U@qQD7  
private String sFilePath; //Saved File's Path [O?z@)dx  
private String sFileName; //Saved File's Name 5nKj )RH7M  
private int nSplitter; //Count of Splited Downloading File xo&]$W8  
$7rq3y  
z}*9uZ  
public SiteInfoBean() -De9_0#R  
{//nSplitter的缺省值为5 -i%e!DgH  
//default value of nSplitter is 5 d%V*|0c)  
this("","","",5); tF{D= ;G  
} /assq+H  
{/ BT9|LI  
Ht&:-F+dm  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) % a@>_  
{ w%JTTru  
sSiteURL= sURL; e,Uo#T6J  
sFilePath = sPath; pUV/Ul]  
sFileName = sName; K*X_FJ  
this.nSplitter = nSpiltter; P_Gw-`L5T  
(q(~de  
*%S"eWb  
} -)RH5WGS  
jAm3HI   
+PcmJ  
public String getSSiteURL() >8qQK r\"  
{ @CZT  
return sSiteURL; E:
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}
,#L=v]  
6er-{.L=  
&C"L  
public void setSSiteURL(String value) Y]B)'[=h  
{ WZ*ws[dVI  
sSiteURL = value; VCD:3U 8  
} 8j=}u/T@F  
x6e}( &p*  
tX> G,hw  
public String getSFilePath() 9*{[buZX  
{ )~HUo9K9  
return sFilePath;
k{Me[B  
} >o7n+Rb:  
29?,<bB)  
3tZ]4ms}  
public void setSFilePath(String value) 98uV6b~g  
{ 2gCX}4^3b  
sFilePath = value; er!DYv  
} :[hgxJu+  
|~X ;1j!  
L;'"A#Pa  
public String getSFileName() ]y1OFKYv  
{ Vp3ZwS  
return sFileName; h3z{(-~y  
} / ;,Md,p  
_YLfL  
lna}@]oR  
public void setSFileName(String value) =A!@6Nw  
{ .`4{9?bR  
sFileName = value; g!+|I  
} + EGD.S{  
w(/aiV  
#w\~&
0  
public int getNSplitter() YQ6f}O  
{ @!yMIM%P  
return nSplitter; vA]W|sLF9  
} q gLaa  
Pl"Nus   
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public void setNSplitter(int nCount) jO1r)hw N>  
{ (tZrw5@  
nSplitter = nCount; /.o^R6  
} .2v_H5<  
} *U]V@;XF  
"F.;Dv9V[0  
.R./0Ot tx  
/* v,4pp@8rv  
**Utility.java 3 %|86:*  
*/ V9dF1Hj  
package NetFox; R)RG[F#  
}5}.lJ:  
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public class Utility { 6u7?dG'4  
pm_u  
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public Utility() sU@nc!&Y@  
{ Ux}(?Z  
Bhp-jq'!B  
_PlKhv}  
} )Ccq4i  
pXtXjb  
//线程睡眠 
j{9D{  
public static void sleep(int nSecond) nAjO6g6E  
{ [`rba'  
try{ 5Drq
9B9;  
Thread.sleep(nSecond); A#95&kJpy  
} i*NH'o/  
catch(Exception e) Y[K*57fs  
{ 8=Z9T<K  
e.printStackTrace (); HLZ;8/|48m  
} U~j ^I^  
} 0QOBL'{7)  
'-"/ =j&d[  
//日志 S7L=#+Z  
public static void log(String sMsg) pt?q#EfFJ  
{ /x[jQM\  
System.err.println(sMsg); 7|[mz> "d  
} vDxe/x%  
B9H@e#[  
8'4S8DM  
public static void log(int sMsg) @
qnD=mE  
{ JAX*hGhkh  
System.err.println(sMsg); U}PiY"S<  
} _G.>+!"2/  
} UM6(s@$  
s8#X3Rp  
*UmI]E{g3(  
/* J_v$YwE  
**TestMethod.java FWHNj.r  
*/ A3S<..g2  
package NetFox; ~;&m*2 |V  
@Q/-s9b  
82QGS$0V  
public class TestMethod { /(BMG/Tb  
q~vDz]\G  
nC}6B).el  
public TestMethod() !gv`FE9y  
{ ///xx/weblogic60b2_win.exe X6mqi;+  
try{ qQsku;C?i  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [
.S#rGYk  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); S4h:|jLUF  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *?Kr*]dnLl  
fileFetch.start(); ;F~LqC$  
} K/3)g9Z&io  
catch(Exception e){e.printStackTrace ();} 3T}izG]  
Qe5U<3{JZ  
j"|=C$Kn/  
} !/3B3cG  
!cAyTl(_  
\&iP`v`K  
public static void main(String[] args) D0#x Lh  
{ !H irhDN  
new TestMethod(); 0 rXxRQ  
} 0Emr<n  
} q"<acqK  
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