http断点续传简单实现（java)

/* S~3|1Hw*tN  
**SiteFileFetch.java *6?mZ*GYY  
*/ KUJLx  
package NetFox; IAQ<|3Q  
import java.io.*; $U_(e:m}f  
import java.net.*; /wLBmh1"  
]Kt@F0U<o  
{5Bj*m5  
public class SiteFileFetch extends Thread { gF,=rT1:>r  
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SiteInfoBean siteInfoBean = null; //文件信息Bean f]r*;YEc4  
long[] nStartPos; //开始位置 _{jC?rzb  
long[] nEndPos; //结束位置 un 5r9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )h,yQ`.  
long nFileLength; //文件长度 ?>B?*IK!  
boolean bFirst = true; //是否第一次取文件 K) }1;  
boolean bStop = false; //停止标志 1b3 a(^^E  
File tmpFile; //文件下载的临时信息 7Y8~")f  
DataOutputStream output; //输出到文件的输出流 W_}j~[&  
w x]?D%l  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） \x-2qlZ  
public SiteFileFetch(SiteInfoBean bean) throws IOException ^t})T*hM0  
{ oMEW5.VX  
siteInfoBean = bean; A^,E~Z!x  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @mCe{r*`  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }? _KZ)  
if(tmpFile.exists ()) RxqNgun@  
{ DP@1to@  
bFirst = false; +E</A:|}S  
read_nPos(); _|u}^ML
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} bJIYe ld  
else $rXCNew(  
{ dNgA C){w  
nStartPos = new long[bean.getNSplitter()]; 486\a  
nEndPos = new long[bean.getNSplitter()]; i3eF_  
} TX=894{nGh  
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U,WMP<5&  
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} Q#3}AO  
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public void run() {N}az"T4f  
{ 7n#-3#_mG  
//获得文件长度 b#?sx"z  
//分割文件 ``CM7|)>`  
//实例FileSplitterFetch 7"'RE95  
//启动FileSplitterFetch线程 ~-k,$J?7  
//等待子线程返回 #//xOL3J  
try{ &9flNoNR9  
if(bFirst) P*!`AWn  
{ JH\:9B+:L  
nFileLength = getFileSize(); Hl}lxK,]  
if(nFileLength == -1) B2kZ_4rB  
{ u9 &$`N_G  
System.err.println("File Length is not known!"); QQW}.>N  
} :6(\:  
else if(nFileLength == -2) )G)6D"5,+G  
{ RyK~"CWT  
System.err.println("File is not access!"); |p/*OFC6  
} /p<9C?
 
else `o#(YEu  
{ inU5eronuj  
for(int i=0;i<nStartPos.length;i++) x\Q}fk?{t  
{ =p4n@C  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ]t)N3n6Bc  
} 9>4#I3  
for(int i=0;i<nEndPos.length-1;i++) lC#wh2B6  
{ Q!q6R^5!K  
nEndPos = nStartPos[i+1]; d'W2I*Zc<  
} 4"@;.C""  
nEndPos[nEndPos.length-1] = nFileLength; rhkKK_  
} |Lg2;P7\  
} &lLk[/b  
,;t:x|{%  
_]*YSeh=  
//启动子线程 gfK_g)'2U  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 26/<\{q~  
for(int i=0;i<nStartPos.length;i++) a"-uJn  
{ `"65 _?B i  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^"7-`<J  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8p 4[:M@  
nStartPos,nEndPos,i); 1*p6UR&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %JBLp xnq  
fileSplitterFetch.start(); ta{24{?M\  
} eOb--@~8  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rY(7IX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ~T;:Tg*  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", KD A8x W  
nEndPos = " + nFileLength); M ]047W  
// fileSplitterFetch[nPos.length-1].start(); 79;uHR&S  
fYPu%MN7  
 +#,J`fV%  
//等待子线程结束 Z5TA4Q+Q  
//int count = 0; Rf0so  
//是否结束while循环 we_CF*zj  
boolean breakWhile = false; ]AA|BeL?|  
d2eXN3"  
XB!qPh.  
while(!bStop) C"kfxpCi  
{ 6qDt6uB  
write_nPos(); s/hgWW$  
Utility.sleep(500); #~'d Y\&  
breakWhile = true; #qVTB@d  
9@CRL=  
8|@) #:  
for(int i=0;i<nStartPos.length;i++) jv.tg,c_6  
{ /x@aAJ|
 
if(!fileSplitterFetch.bDownOver) [[c0
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{ 0]5XTc3r  
breakWhile = false;  jfK&CA  
break; ifS#9N|8  
} >rlUV"8jY;  
} ynw(wSH=  
if(breakWhile) >bWpj8Kv  
break; ,j XK  
O>~@>/#  
Q>4NUq  
//count++; JYWoQ[ZO#>  
//if(count>4) Q  
// siteStop(); W#U|;@"  
} 9]+zZP_#  
lwf
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4*Hzys[{  
System.err.println("文件下载结束！"); BDf M4  
} F)~>4>hPr  
catch(Exception e){e.printStackTrace ();} "y~*1kBu  
} q`mxN!1[  
sDBSc:5+e  
~8&->?{  
//获得文件长度 ! 7V>gWhR  
public long getFileSize() H_@6!R2  
{ DNZ,rL:h  
int nFileLength = -1; b4wT3  
try{ 445JOP  
URL url = new URL(siteInfoBean.getSSiteURL()); _*UI}JtlS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :q3w;B~  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3:Nc`tM_  
3PvxU|*F  
U;iCH  
int responseCode=httpConnection.getResponseCode(); I`oJ
OLV  
if(responseCode>=400) d1_kw A2y  
{ (b~l.@xh  
processErrorCode(responseCode); \},H\kK+^  
return -2; //-2 represent access is error -3yK>\y=|  
} 5ph CEKt;  
rZwSo]gp  
@+t|Aa^g  
String sHeader; 6h5g!GQD  
! (lF#MG}  
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for(int i=1;;i++) 7WH'GoBh  
{ 'qEw]l  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Z":m(}u O  
//Utility.log(in.readLine()); r'nPP6`  
sHeader=httpConnection.getHeaderFieldKey(i); pf'DbY!  
if(sHeader!=null) -zYa@PW  
{ 423%K$710  
if(sHeader.equals("Content-Length")) 9Vq  
{ ma-GvWD2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); UH0l8ixc  
break; Cxq|N]E  
} p,k1*|j  
} wz3X;1l`c  
else Jc?zX8>Ae:  
break; G~C-tAB  
} 5\zR>Tg".  
} HD#>K 7  
catch(IOException e){e.printStackTrace ();} ;39a`  
catch(Exception e){e.printStackTrace ();} zd2_k 9  
0kCo0{+n  
c;/vzIJj  
Utility.log(nFileLength); VF11eZ"  
4
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return nFileLength; }l+_KA  
} |LJv*  
@TW:6v`  
v&G9HiH  
//保存下载信息（文件指针位置） ,&3+w~Ua  
private void write_nPos() Y(`Bc8h  
{ *YH!L{y  
try{ ):4)8@]5M  
output = new DataOutputStream(new FileOutputStream(tmpFile)); x`+M#A()/  
output.writeInt(nStartPos.length); ~pp< T  
for(int i=0;i<nStartPos.length;i++) q&[G^9  
{ i[LnU#+  
// output.writeLong(nPos); ~M* UMF^  
output.writeLong(fileSplitterFetch.nStartPos); yuC$S&Y>!  
output.writeLong(fileSplitterFetch.nEndPos); 6d8)]  
} L"vk ^>E6  
output.close(); N/WtQSl  
} }@6yROy.  
catch(IOException e){e.printStackTrace ();} j<)$ [v6  
catch(Exception e){e.printStackTrace ();} !nL94:8U  
} Ff>X='{  
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[u*7( 4e  
//读取保存的下载信息（文件指针位置） :j3^p8]  
private void read_nPos() yj'lHC  
{ > .}G[C  
try{ X} V]3  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); B>'J5bZsw  
int nCount = input.readInt(); mpD.x5jm<  
nStartPos = new long[nCount]; x])j]k  
nEndPos = new long[nCount]; uL7}JQ,  
for(int i=0;i<nStartPos.length;i++) Yur}<>`(  
{ D@sMCR  
nStartPos = input.readLong(); n%\\1  
nEndPos = input.readLong(); K!(WcoA&2i  
} C$q-WoTM(  
input.close(); a}` M[%d7  
} `}P9[HP  
catch(IOException e){e.printStackTrace ();} 27[e0 j  
catch(Exception e){e.printStackTrace ();} (&)uWjq `  
} p cUccQ  
/QL<>g  
cahlYv'  
private void processErrorCode(int nErrorCode) >cjxu9Vr1K  
{ m,hqq%qz  
System.err.println("Error Code : " + nErrorCode); (W"0c?i|]  
} `_/1zL[  
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}Gb^%1%M  
//停止文件下载 1$# r)S[*  
public void siteStop() <oP`\m  
{ PDc4ok`)  
bStop = true; $=>:pQbBVX  
for(int i=0;i<nStartPos.length;i++) B^/Cx  
fileSplitterFetch.splitterStop(); 0Z((cI\J  
. P44t  
GM;uwL#  
} d72( g$F  
} R.* k7-(;  
//负责部分文件的抓取 
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**FileSplitterFetch.java O.Dz}[w  
*/ bZK`]L[   
package NetFox; %NlmLWF.  
*a_QuEw_k  
4 }_}3.  
import java.io.*; u-n$%yDS  
import java.net.*; ZA_~o#0%  
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public class FileSplitterFetch extends Thread {  ;1,#rTs  
ZFX}=?+  
:+^`VLIf  
String sURL; //File URL >4>. Ycp  
long nStartPos; //File Snippet Start Position {Xpjm6a7  
long nEndPos; //File Snippet End Position \(f82kv  
int nThreadID; //Thread's ID ]Zay9jD}c-  
boolean bDownOver = false; //Downing is over {az LtTh  
boolean bStop = false; //Stop identical OB(~zUe.R  
FileAccessI fileAccessI = null; //File Access interface DVs$3RL  
kz#x6
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 9p02K@wkD  
{ A1zV5-E/  
this.sURL = sURL; o'P
[uB/  
this.nStartPos = nStart; *"/BD=INv}  
this.nEndPos = nEnd; 9<!??'@f  
nThreadID = id; m`XaY J  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \q-["W34  
} M tDJ1I%  
J{EK}'  
iu+H+_  
public void run() ONcS
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{ -Vg0J6x  
while(nStartPos < nEndPos && !bStop) UU =,Brb  
{ =>TXo@rVN  
sh<JB`^$(?  
8p~[8}  
try{ tnmz5Q  
URL url = new URL(sURL); ac4dIW{$3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); NlG!_D"(y  
httpConnection.setRequestProperty("User-Agent","NetFox"); aI\>=*HF  
String sProperty = "bytes="+nStartPos+"-"; ok&v+A  
httpConnection.setRequestProperty("RANGE",sProperty); }2?-kj7  
Utility.log(sProperty); Si#XF[/  
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99q$>nx,w  
InputStream input = httpConnection.getInputStream(); ,n5 [Y)  
//logResponseHead(httpConnection); Zr\G=0`  
1-4*Y
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]=0D~3o3  
byte[] b = new byte[1024]; +w3k_^X9c  
int nRead; x4_FG{AIu  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 7 Uu  
{ 9JC8OSjJ  
nStartPos += fileAccessI.write(b,0,nRead); !.{{QwZ  
//if(nThreadID == 1) i6h0_q
8 >  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); CBx5:}t  
} |-AR)Smt  
c*>SZ'T\  
N;,N6&veK/  
Utility.log("Thread " + nThreadID + " is over!"); 6^p>f:5  
bDownOver = true; 3o__tU)B  
//nPos = fileAccessI.write (b,0,nRead); ##NowO  
} $J:~jY/J  
catch(Exception e){e.printStackTrace ();} !.={p8X-x  
} CH h6Mnw  
} !3at(+4  
Lr(wS {  
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//打印回应的头信息 OEN'c0;5  
public void logResponseHead(HttpURLConnection con) Zf`ddT  
{ j~9,Ct  
for(int i=1;;i++) 0.t1p(x;  
{ W&k2z,|  
String header=con.getHeaderFieldKey(i); TH}
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if(header!=null) N(&/ Ud  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); VrRBwvp-K  
Utility.log(header+" : "+con.getHeaderField(header)); }"c
hm=b  
else )N&v.w  
break; 3PZwz^oRh9  
} /`VtW$9-  
} .mS'c#~5Y  
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public void splitterStop() *8QGv6*vQ  
{ 8[z& g%u  
bStop = true; 9ev"BO  
} d`+cNKf  
>*mLbp"  
s%qK<U4@;Q  
} ]+0I8eerd  
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)wYbcH  
/* 80ms7 B  
**FileAccess.java d~J4&w  
*//文件访问(定位，写) wms8z  
package NetFox; 7_#i,|]58  
import java.io.*; =i)k@w_(x  
7^:0?Q  
KEj-y+  
public class FileAccessI implements Serializable{ 9
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vN4g#,<  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Z66@@?`  
RandomAccessFile oSavedFile; XmoS$/#"  
long nPos; #G ZGk?  
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public FileAccessI() throws IOException FVcooV  
{ 3$`qy|=zO  
this("",0); M e  
} U8KEg)Msk  
GzUgzj|BN~  
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public FileAccessI(String sName,long nPos) throws IOException 0zAj.iG  
{ L);kwx7{LW  
oSavedFile = new RandomAccessFile(sName,"rw"); /TgG^|  
this.nPos = nPos; q,a|lH  
oSavedFile.seek(nPos); VFMg$qv|_  
} cx8H.L  
WNPdym  
"8"7AoE  
public synchronized int write(byte[] b,int nStart,int nLen) ' RjFWHAp  
{ <4Jo1  
int n = -1; 8BZDaiE"  
try{ S|%f<zAtJ  
oSavedFile.write(b,nStart,nLen); "syf@[tz7  
n = nLen;
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} hQfxz,X  
catch(IOException e) Q pY:L  
{ |3MqAvPJ  
e.printStackTrace (); i.Qy0  
} ` 0k  
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return n; *5#Y[c  
} ZIx,?E+eJ  
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} ?8X+)nU@  
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'N0/;k0ax  
/* p' FYK|  
**SiteInfoBean.java Bk1Q.Un  
*/ .Go3'$'v  
package NetFox; 9)QvJ87e@7  
V<@]Iv  
|:tFQ.Z'2  
public class SiteInfoBean { h2Z Gh  
iCIu]6  
zrt8ze=Su  
private String sSiteURL; //Site's URL a-,BBM8|  
private String sFilePath; //Saved File's Path @"H+QVJ@  
private String sFileName; //Saved File's Name P~:W+!@5v  
private int nSplitter; //Count of Splited Downloading File ht S5<+Y  
$N=A,S  
Dg@>d0FW  
public SiteInfoBean() 3D k W  
{//nSplitter的缺省值为5 Px}#{fkS  
//default value of nSplitter is 5 mMw&{7b:  
this("","","",5); U&/Jh^Yy  
} 9\i,3:Qc  
Tc
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w8(qiU  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _~DFZt@T  
{ /9WR>NUAO  
sSiteURL= sURL; *IGgbg[0  
sFilePath = sPath; n5%rsNxg  
sFileName = sName; eGblQGRS  
this.nSplitter = nSpiltter; SN'LUwaMp!  
2`l$uEI3oJ  
J%;TK6  
} R)#D{/#FW  
XWbe|K!e  
/cr.}D2O  
public String getSSiteURL() gR(*lXm5w  
{ y2^r.6"O  
return sSiteURL; Sj}@5 X6 C  
} y^:g"|q  
>'8.>f  
3Cwqy#X#8  
public void setSSiteURL(String value) VWmZ|9Ri  
{ o;\0xuM@  
sSiteURL = value; 2HMlh.R(C  
} .)B_~tct  
Y'Jb@l`$-  
^^%sPtp  
public String getSFilePath() ~^IS{
1  
{ /z,sM"d  
return sFilePath; z8mR< q%`  
} >GgX-SZ%  
r 06}@7  
X1i6CEa<  
public void setSFilePath(String value) |jaUVE_2[  
{ &|26x >  
sFilePath = value; U\ y?P:yy  
} Om{[ <tL  
>NW /0'/  
M\8FjJ>9  
public String getSFileName() 3`k1  
{ ho@f}4jhQ3  
return sFileName; ALwkX"AN  
} *n2Q_o  
yIbz\3  
M0x5s@  
public void setSFileName(String value) o 1#XM/Z  
{ sN7I~  
sFileName = value; _4rb7"b1  
} L;
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co<){5zOT  
7vcYI#(2 Y  
public int getNSplitter() JHc|.2Oe  
{ @k,u xe-  
return nSplitter; Z%XBuq:BY  
} Nd#t !=  
us4.-L  
X c,UR.  
public void setNSplitter(int nCount) ^Q4w<sX'  
{ ||}|=Sz  
nSplitter = nCount; <Ky\^  
} s+tS4E?  
} C%"h1zWE:  
o~gduNG#  
rr*",a"}m  
/* @|%t<{y^I  
**Utility.java naXo <B  
*/ JXGIVH?Rpu  
package NetFox; av gGz8  
V_~}7~ I  
'9*wr*  
public class Utility { W2yNEiH  
%7O`]ik:  
"(/|[7D)  
public Utility() l?a(=  
{ ,<|EoravH  
)dJM  
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} <hdR:k@#  
//e.p6"8h  
//线程睡眠 _w^p~To^  
public static void sleep(int nSecond) C\.?3  
{ ?;|$R   
try{ s:R>uGYOd  
Thread.sleep(nSecond); :I F&W=?9  
} 8S@ ~^D  
catch(Exception e) h^~eTi;c]Q  
{ ~0|~Fg  
e.printStackTrace (); k^]+I%?Q  
} Fmt5"3B  
} \@['V   
rd0BvQ9TK  
//日志 aAu upPu  
public static void log(String sMsg) p4W->AVv$  
{ OWB^24Z&3  
System.err.println(sMsg); [G[HQ)A  
} b\][ x6zJp  
_7]5Q  
<3 AkF# C9  
public static void log(int sMsg) idPkJf/  
{ o&;+!Si@T  
System.err.println(sMsg); {NKDmeg:D  
} y= cBpC  
} ;r- \h1iA'  
?_m;~>C  
0O
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/* )`-9WCd&  
**TestMethod.java A7+eWg{  
*/ *u 3K8"XZ  
package NetFox; 6peO9]Zy  
Nh]eZ3O  
a%;$l_wVT:  
public class TestMethod { *J8j_-i,R  
2y ~]Uo  
eAu3,qoM  
public TestMethod() rNfu
a   
{ ///xx/weblogic60b2_win.exe 0}PW
?t76  
try{ K^A\S  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); o*f7/ZP1o  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); V{{b^y  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ub+>i  
fileFetch.start(); 0RYh4'=F  
} SG8|xoL  
catch(Exception e){e.printStackTrace ();}
3,oFT   
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pL.r 9T.  
} S<88>|&n]  
Nypa,_9}  
f*1.Vg0`-  
public static void main(String[] args) FFR_1Vf  
{ K$#(\-M  
new TestMethod(); -g;iMqh#  
} -7'>Rw  
} {{SQL)yJ  
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