http断点续传简单实现（java)

/* h8:5[;e  
**SiteFileFetch.java /N=M9i
\;  
*/ MmD1@fW32#  
package NetFox; rl:D>t(:.  
import java.io.*; zj7?2  
import java.net.*; (RI+4V1  
A(ZtA[G  
r%xf=};  
public class SiteFileFetch extends Thread { )KUEkslR:  
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7loIjT7  
SiteInfoBean siteInfoBean = null; //文件信息Bean U_@Dn[/:  
long[] nStartPos; //开始位置 7o$S6Y;c4  
long[] nEndPos; //结束位置 Z6_fI  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9lc{{)m2)  
long nFileLength; //文件长度 z{A~d  
boolean bFirst = true; //是否第一次取文件 @K}Bll.E  
boolean bStop = false; //停止标志 mZ#h p}\.  
File tmpFile; //文件下载的临时信息 !.[H!-V.  
DataOutputStream output; //输出到文件的输出流 -
02.n
}u>  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） z;Dc#SZnO(  
public SiteFileFetch(SiteInfoBean bean) throws IOException lBNB8c0e"{  
{ .t$1B5  
siteInfoBean = bean; i`7:^v;  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); UUqA^yJ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }/M`G]wT#  
if(tmpFile.exists ()) ?Y_!Fr3V  
{ :KBy(}V  
bFirst = false; (dAE  
read_nPos();
<Eh_  
} WU{9lL=  
else mEq>{l:  
{ ~o8x3`CoF  
nStartPos = new long[bean.getNSplitter()];    
nEndPos = new long[bean.getNSplitter()]; h:{^&d a  
} _TjRvILC  
G!g];7PG(  
RBV*e9P%  
I4MZJAYk  
} 0EBHRY_F  
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public void run() zI.:1(,  
{ =iE)vY,?"}  
//获得文件长度 F
Us57 V  
//分割文件 PQ(/1v   
//实例FileSplitterFetch !X+}W[Ic^  
//启动FileSplitterFetch线程 3'6by!N,d  
//等待子线程返回 i#(+Kxr]>  
try{ Y>I9o)KR  
if(bFirst) 30Udba+{]p  
{ cb%ML1c  
nFileLength = getFileSize(); c<imqDf  
if(nFileLength == -1) z?.XVk-  
{ -e_B  
System.err.println("File Length is not known!"); jYnP)xX;  
} V(3rTDg  
else if(nFileLength == -2) Gu#wH  
{ =7Sw29u<  
System.err.println("File is not access!"); k;pU8y6Y  
} Hw%lT}[O  
else Dj x[3['  
{ #-K,,"  
for(int i=0;i<nStartPos.length;i++) RKwuvVI  
{ ?/^{sW' |  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); m";?B1%x  
} 'Jl3%axR  
for(int i=0;i<nEndPos.length-1;i++) C&&33L  
{ 2 D!$x+|  
nEndPos = nStartPos[i+1]; Vl0Y'@{  
} qHC/)M#L  
nEndPos[nEndPos.length-1] = nFileLength; !&5B&w{u~!  
} Jb]22]  
} Wo<kKkx2  
:0(:}V3z\  
b0yNc:  
//启动子线程 1'SpJL1u~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; )C%S`d<%,  
for(int i=0;i<nStartPos.length;i++) g/`z.?  
{ K#a_7/!v/  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rwY{QBSf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Z]=9=S| .4  
nStartPos,nEndPos,i); >(eR0.x  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [_zoJ  
fileSplitterFetch.start(); RbJbVFz8C  
} W>m#Mz  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8t1,_,2'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); iS}~e{TP/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", a\Dw*h?b~  
nEndPos = " + nFileLength); 0m'tPFQ|  
// fileSplitterFetch[nPos.length-1].start(); ^LAdN8Cbb  
;#S4$wISw`  
!E9A=
u{  
//等待子线程结束 LGPg\g`  
//int count = 0; HOlMj!.  
//是否结束while循环 4nGr?%>  
boolean breakWhile = false; 8|-064i>  
95oh}c  
wPH1g*U  
while(!bStop) #5mnSky+s  
{ A?Gk8  
write_nPos(); Mx=L lC)  
Utility.sleep(500); :1e'22[=.  
breakWhile = true; <R8!f
c{`  
lBfG#\rdW~  
6x"|,,&MD0  
for(int i=0;i<nStartPos.length;i++) $jL+15^N0+  
{ ~A-VgBbU>_  
if(!fileSplitterFetch.bDownOver) 07A2@dx  
{ l5,}yTUta  
breakWhile = false; {y==8fCJ  
break; _`q ei0  
} Fn*)!,)  
} PZSi}j/  
if(breakWhile) &-4SA j  
break; =\)qUs\z  
h"ko4b3^'@  
Rb_+C  
//count++; ?8R  
//if(count>4) I)}T4OOc/  
// siteStop(); Wup%.yT~Ds  
} Nzel^~  
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}ygxm
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System.err.println("文件下载结束！"); I=o/1:[-  
} L6"?p-:@'  
catch(Exception e){e.printStackTrace ();} <" F|K!Tz  
} Ol1P  
+u'y!@VV  
7g
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//获得文件长度 0} Lx}2  
public long getFileSize() >d#Ks0\&  
{ 6;hZHe'W  
int nFileLength = -1; +B-;.]L T  
try{ zqAp7:  
URL url = new URL(siteInfoBean.getSSiteURL()); ~Is-^k)y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); S9@)4|3C|p  
httpConnection.setRequestProperty("User-Agent","NetFox"); h,)UB1  
=1h> N/VJ  
C4 @"@kbr  
int responseCode=httpConnection.getResponseCode(); hYv;*
]  
if(responseCode>=400) 4z^5|$?_ta  
{ xgv&M:%D-  
processErrorCode(responseCode); h6C:`0o  
return -2; //-2 represent access is error Kgu#Mi~  
} !nyUAZ9 :  
iXFN|ml  
`=rDB7!$yL  
String sHeader; !Zma\Ip  
%2`geN<  
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for(int i=1;;i++) g)#.|d+  
{ ~4[4"Pi>|  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); O5?3nYHa  
//Utility.log(in.readLine());  h@"u==0  
sHeader=httpConnection.getHeaderFieldKey(i); Fg-4u&Ik  
if(sHeader!=null) T1c.ER}17  
{ jq"iLgEMO  
if(sHeader.equals("Content-Length")) |_
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{ _^cFdP)8|  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); aO>Nev  
break; >KMTxHE`+  
} 0I \l_St@  
} TNK~ETE4  
else S#l6=zI7^R  
break; 0xe*\CAo  
} lpHz*NZ0  
} u&s>UkR  
catch(IOException e){e.printStackTrace ();} /6a617?9J  
catch(Exception e){e.printStackTrace ();} SY
miDR  
3tIno!|  
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Utility.log(nFileLength); [^GXHE=  
TBp$S=_**  
 rytaC(  
return nFileLength; WnZn$N.  
} :OvTZ ?\  
,I|TjC5  
t+`>zux5(T  
//保存下载信息（文件指针位置） @2Ca]2,4  
private void write_nPos() 1>e%(k2w%  
{ UO{3vry48  
try{ ]@bu%_s"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); @-F[3`HeA  
output.writeInt(nStartPos.length); lL{1wCsl  
for(int i=0;i<nStartPos.length;i++) O9(6?n  
{ #K_E/~  
// output.writeLong(nPos); zM*PN|/%sH  
output.writeLong(fileSplitterFetch.nStartPos); _|%l) KO  
output.writeLong(fileSplitterFetch.nEndPos); " .:b43Z  
} %V3xO%  
output.close(); *{e?%!Q  
} C.}Vm};M  
catch(IOException e){e.printStackTrace ();} }|!9aojr  
catch(Exception e){e.printStackTrace ();} ( [m[<  
} ~*,e&I  
"T,^>xD  
M~k2Y$}R  
//读取保存的下载信息（文件指针位置） 4ZN&Yf`  
private void read_nPos() ?3) IzzO  
{ TB  
try{ MY `V0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6}9`z8  
int nCount = input.readInt(); Ko|p&-Z;  
nStartPos = new long[nCount]; #3m7`}c  
nEndPos = new long[nCount]; 't:s6  
for(int i=0;i<nStartPos.length;i++) #>/stU-  
{ m^rrbU+HM?  
nStartPos = input.readLong(); iS%md  
nEndPos = input.readLong(); b`Agb<x"  
} /,cyp.  
input.close(); AD/7k3:  
} ~56F<=#,  
catch(IOException e){e.printStackTrace ();} )@OKL0t  
catch(Exception e){e.printStackTrace ();} 'z.: e+Q_  
} =$t  
:i>/aRNh1  
t<QSp6n""  
private void processErrorCode(int nErrorCode) G8E=E<Yg~  
{ r=o\!sh[  
System.err.println("Error Code : " + nErrorCode); +f- E8q  
} Lj(y>{y  
-<GSHckD  
6*92I  
//停止文件下载 ka$oUB)iQ  
public void siteStop() "Yu';&  
{ +zup+=0e  
bStop = true; '7Aj0U(  
for(int i=0;i<nStartPos.length;i++) 31@m36? X  
fileSplitterFetch.splitterStop(); uY~xHV_-  
v%%;Cp73  
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} F;,LY:s|Z  
} V;}6C&aP.  
//负责部分文件的抓取 KKLW-V\6K  
**FileSplitterFetch.java Rw9 *!<Izt  
*/ BDCFToSf|  
package NetFox; 3+v+_I>%k  
LG qg0(  
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import java.io.*; 9/nS?>11  
import java.net.*; 6q!smM  
^s=p'&6  
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public class FileSplitterFetch extends Thread { ?{Gf'Y}y&  
c8 xZT  
d].(x)|st  
String sURL; //File URL Gap\~Z@L  
long nStartPos; //File Snippet Start Position #g6*s+Gm  
long nEndPos; //File Snippet End Position VP<_~OLc  
int nThreadID; //Thread's ID }N6r/ VtOQ  
boolean bDownOver = false; //Downing is over /EpsJb`kj  
boolean bStop = false; //Stop identical 4}\Dr %US  
FileAccessI fileAccessI = null; //File Access interface (.DX</f/4  
H!+T2<F9R  
w[
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException tbP ;iK'  
{ [qEd`8V(  
this.sURL = sURL; h5.>};"@'  
this.nStartPos = nStart; lN-[2vT<  
this.nEndPos = nEnd; !]-ET7  
nThreadID = id; Vu`O%[Q/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 B
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} c!{]Z_d\  
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public void run() < x==T4n/  
{ CAPPOh  
while(nStartPos < nEndPos && !bStop) @9wug!,  
{ ;1&7v  
bz=B&YR  
8+irul{H_  
try{ 5ma*&Q8+  
URL url = new URL(sURL); A]FjV~PB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '#fwNbD  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3~%wA(|A  
String sProperty = "bytes="+nStartPos+"-"; ?l3PDorR  
httpConnection.setRequestProperty("RANGE",sProperty); sBo|e]m#  
Utility.log(sProperty); w53+k\.  
zeZ}P>C  
r^$4]@Wn  
InputStream input = httpConnection.getInputStream(); F5#P{zk|  
//logResponseHead(httpConnection); 9Fkzt=(E~  
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byte[] b = new byte[1024]; y^SDt3Am  
int nRead; V+M=@Pvp9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) #!WD1a?L  
{ pd[?TyVK;  
nStartPos += fileAccessI.write(b,0,nRead); kdX]Afyj  
//if(nThreadID == 1) X8Xw'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5V^+;
eO  
} zoU-*Rs6  
-zq_W+)ks  
@AgV7#  
Utility.log("Thread " + nThreadID + " is over!"); 7:h8b/9  
bDownOver = true; Ba9le|c5  
//nPos = fileAccessI.write (b,0,nRead); .-6B6IEI_"  
} >$.lM~k  
catch(Exception e){e.printStackTrace ();} b\U p(]  
} f0^DsP  
} iYyJq;
S   
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I  
uH6QK\  
//打印回应的头信息 0PK*ULwSN  
public void logResponseHead(HttpURLConnection con) 3r)<:4a u&  
{ ^_cR  
for(int i=1;;i++) c%|18dV  
{ jNIZ!/K  
String header=con.getHeaderFieldKey(i); tyH*epanw  
if(header!=null) {=Y.Z1E:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ny.s u?E  
Utility.log(header+" : "+con.getHeaderField(header)); m 8Q[+_:$H  
else YXR%{GUP[  
break; j^g^=uau  
} Vko1{$}t  
} W* XG9  
d +]Gw  
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public void splitterStop() f/r@9\x  
{ (mOUbO8  
bStop = true; >|Hd*pg))  
} Gj.u
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"uz}`G~O
 
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} }538vFNi  
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/* H^N@fG<*dh  
**FileAccess.java Z.
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*//文件访问(定位，写) kO]],Vy`  
package NetFox; @y (9LSs  
import java.io.*; )<D(Mb2p|  
r&G
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!;YmLJk;hN  
public class FileAccessI implements Serializable{ CywQ  
]yxRaW9f  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 a-t}L{~  
RandomAccessFile oSavedFile; :\+;5Se+l  
long nPos; L y!!+UM\  
8H>: C(h  
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public FileAccessI() throws IOException Z|FWQ8gZ4m  
{ 8TK&i,  
this("",0); u |hT1l  
} ^_5Nh^  
.,C8ASfh  
}}";)}C`  
public FileAccessI(String sName,long nPos) throws IOException PKT/U^2X]  
{ ^<0azza/(  
oSavedFile = new RandomAccessFile(sName,"rw"); Lh%>> Ht{  
this.nPos = nPos; }*2q7K2bj  
oSavedFile.seek(nPos); piRP2Lbm*  
} p&nIUx"  
g,5r)FU`  

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public synchronized int write(byte[] b,int nStart,int nLen) u0;FQr2  
{  xZ*.@Pkr  
int n = -1; 7R 40t3  
try{ tFvc~zz9  
oSavedFile.write(b,nStart,nLen); Zhl}X!:c?\  
n = nLen; \\F@_nB,b  
} a'LM6A8~x  
catch(IOException e) L6^Qn%:OTd  
{ edt(Zzk@3-  
e.printStackTrace (); ,cR=W|6cQm  
} 4uW}.7
R'  
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R"S,&  
return n; ~aK@M4  
} Wx;`=9  
/7$3RV(  
s V70a3#  
} !5rja-h  
SBnwlM"AN  
0ciPH:V  
/* -q9`Btz  
**SiteInfoBean.java C F2*W).+  
*/ n
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package NetFox; k_rtsN  
;%r#pv~  
QRs!B!Fn0  
public class SiteInfoBean { E\5cb[Y  
':kj\$U  
DwXzmp[qWH  
private String sSiteURL; //Site's URL $z-zscco  
private String sFilePath; //Saved File's Path *5DOTWos  
private String sFileName; //Saved File's Name f)xHSF"  
private int nSplitter; //Count of Splited Downloading File gDP\u<2!  
<$WRc\}&g  
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public SiteInfoBean() tBNkVh(c  
{//nSplitter的缺省值为5 %Lec\(-4L  
//default value of nSplitter is 5 $a|D
R  
this("","","",5); \;w+_<zE5{  
} %4:tRF  
o|\0IG(\  
?QGAiu0  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \de824  
{ ?UAB}CjY  
sSiteURL= sURL; IfHB+H   
sFilePath = sPath; /n= %#{  
sFileName = sName; ,LjB%f[  
this.nSplitter = nSpiltter; xP<cF  
{/]Ks8`Dm  
f n9[Li  
} $`:/OA<.  
hcEUkD  
P 0xInW F  
public String getSSiteURL() S0V%JY;Gv  
{ VXforI  
return sSiteURL; 7xAzd# c?=  
} zi~_[l-  
)NeI]p  
VmLV:"P}^  
public void setSSiteURL(String value) A&#P=mj  
{ |A_yr/f  
sSiteURL = value; OO.. Y  
} wv>uT{g#  
Z~}=q  
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public String getSFilePath() 30 VvZb  
{ 5b9v
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return sFilePath; $QQv$  
} bd[zdL#4K  
o<f[K}t9  
\/C-e  
public void setSFilePath(String value) @`<vd@  
{ Ea@N:t?(8=  
sFilePath = value; KDP7u  
} WDr'w'  
^Z7])arA  
^7C?yC  
public String getSFileName() Yr@)W~  
{ ?pdvFM  
return sFileName; 7bioLE  
} Ug=8:a(U.  
/[YH W]  
M9{?gM9  
public void setSFileName(String value) b?-Ep?G'\  
{ EB'(%dH  
sFileName = value; tp2CMJc{L  
} p:u?a,p  
S/CT;M@W  
"WOY`su>  
public int getNSplitter() +OkR7bl  
{ '`^<*;w  
return nSplitter; BBy"qkTe  
} 1bb~u/j
U  
:.B};;N  
$F
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public void setNSplitter(int nCount) U@v=q9'W  
{ y?W8FL  
nSplitter = nCount; '|n-w\ >Wv  
} Hw8`/'M=%5  
} cF_hU"  
n|F$qV_p\  
HqXaT6#/  
/* b]hP;QK`U$  
**Utility.java 2`,{IHu*!  
*/ \?)@ #Qs  
package NetFox; 6P;JF%{J  
N<ww&GXBX  
_@0>yMZ^  
public class Utility { e"^* ~'mJ  
VJ P]Jy_  
jJ-j   
public Utility() b@@`2O3"  
{ 6R% I)  
(NUwkAOM}  
'M2Jw8i  
} UX=JWb_uGm  
RWf4Wh?d  
//线程睡眠 ('!90  
public static void sleep(int nSecond) &G?b|Tb2  
{ ?1 $.^  
try{ zRsG$)B  
Thread.sleep(nSecond); A<.`HCv2  
} 0hK)/!Y  
catch(Exception e) 5%C-eB  
{ >(EMZ5  
e.printStackTrace (); uNV(r"
 
} pulE6T7x  
} CZg$I&x  
6JBE=9d-Q  
//日志 I0oM\~#  
public static void log(String sMsg) Ro`Hm8o/  
{ nb0V~W  
System.err.println(sMsg); ,6?L.L  
} +avu&2B  
rwr>43S5<3  
:~BY[")  
public static void log(int sMsg) k0.|%0?K  
{ dC;@ Fn  
System.err.println(sMsg); -xtj:UO  
} Hw[u Sv8  
}
L!:}  
01q5BQ7u  
g83]/s+  
/* x7 jE Ns )  
**TestMethod.java qazM@  
*/ aLTC#c%U  
package NetFox; [_ESR/&N  
u$d T^c
 
"1_eZ`  
public class TestMethod { XJTY91~R  
S{aK\>>H  
MDa 4U@Q  
public TestMethod() dN J2pfvv  
{ ///xx/weblogic60b2_win.exe h{I)^8,M  
try{ DU
#6%8~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); S!cc%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ziCTvT  
SiteFileFetch fileFetch = new SiteFileFetch(bean); JX@/rXFY}  
fileFetch.start(); %g}ri8  
} PvX>+y5  
catch(Exception e){e.printStackTrace ();} sF}T9Ue  
P#bZtWx'<N  
Jw?J(ig^  
} 85YE6^y  
Au08k}h<G  
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public static void main(String[] args) _] veTAV  
{  U=MFNp+  
new TestMethod(); N=lFf+  
} wYK-YY:Q3  
} B$"CoLC7+  
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