http断点续传简单实现（java)

/* @>*r2=#14  
**SiteFileFetch.java \NZ@>on  
*/ $MqEM~^=  
package NetFox; !K6:5V%q$  
import java.io.*; ";jKTk7  
import java.net.*; h0] bIT{  
\ [bJ@f*."  
mWF\h>]|.  
public class SiteFileFetch extends Thread { {8 #  
|G)P I`BH  
;b}cn!U]  
SiteInfoBean siteInfoBean = null; //文件信息Bean (3WK2IM^  
long[] nStartPos; //开始位置 !i_~<6Wa7  
long[] nEndPos; //结束位置 NvvD~Bb  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;#L]7ZY9:-  
long nFileLength; //文件长度 B[~Q0lPih  
boolean bFirst = true; //是否第一次取文件 <U
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boolean bStop = false; //停止标志 &PPYxg<  
File tmpFile; //文件下载的临时信息 QtA@p  
DataOutputStream output; //输出到文件的输出流 MxOIe|=&  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 4C[kj  
public SiteFileFetch(SiteInfoBean bean) throws IOException 2?F?C  
{ Z.`0  
siteInfoBean = bean; 97dF  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =)}Yw)
 
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5/R ~<z  
if(tmpFile.exists ()) O03F@v  
{ %?3$~d\n  
bFirst = false;
d ATAH}r&  
read_nPos(); [HhaBy9  
} u"MfxW`  
else #y'p4Xf  
{ W=y9mW|p/  
nStartPos = new long[bean.getNSplitter()]; Y()
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nEndPos = new long[bean.getNSplitter()]; s<;{q+1#  
} cv;2zq=T  
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} 7)RR
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public void run() '|}H,I{  
{ /.(~=6o5  
//获得文件长度 dt0(04  
//分割文件 l,5isq ;m  
//实例FileSplitterFetch E5?$=cL?  
//启动FileSplitterFetch线程 r`$P60,@C  
//等待子线程返回 c_t7<  
try{ MO? }$j  
if(bFirst) )Fw#]~Z  
{ Fr-Vq=j&  
nFileLength = getFileSize(); H vHy{S4  
if(nFileLength == -1) ]F"P3':  
{  He%v4S  
System.err.println("File Length is not known!"); >3,}^`l  
} @YVla!5O@  
else if(nFileLength == -2) ^9]g5.z:  
{ H6Ytp^~>  
System.err.println("File is not access!"); _0y]U];ce  
} OKAmw>{  
else WHqw=!G  
{ ps^["3e  
for(int i=0;i<nStartPos.length;i++) *uSlp_;kB  
{ ZENblh8fs  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); +Ht(_+To1  
} _;R#B`9Iu  
for(int i=0;i<nEndPos.length-1;i++) TrN
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{ Q3'P<"u  
nEndPos = nStartPos[i+1]; q
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} -v:3#9uX)  
nEndPos[nEndPos.length-1] = nFileLength; ,kUg"\_k  
} ,4k3C#!.i  
} @vL0gzE?nB  
y4VO\N!  
!hE F.S  
//启动子线程 $ nMx#~>a  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 7q:;3;"9  
for(int i=0;i<nStartPos.length;i++) >}/T&S  
{ ?BbEQr  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), );?tGX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), C`uL 4r  
nStartPos,nEndPos,i); >|0I\{C  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1ed^{Wa4$9  
fileSplitterFetch.start(); {suQ"iv  
} }rnu:7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), p&\DG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); : rudo[L  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 'UTMEN&  
nEndPos = " + nFileLength); b>9?gmR{  
// fileSplitterFetch[nPos.length-1].start(); 7q{yLcC"  
dA<SVk*0Q  
'@zMZc!  
//等待子线程结束 o?
+?@Xb'  
//int count = 0; DHbS=Iih  
//是否结束while循环
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boolean breakWhile = false; ItVVI"-  
p<&>1}j=  
Y/LS(b*  
while(!bStop) "Bz#5kqnl  
{ i~3\dp  
write_nPos(); >[~`rOU*|Y  
Utility.sleep(500); Nfv` )n@  
breakWhile = true; Y\ ;hjxR-  
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for(int i=0;i<nStartPos.length;i++) ~@e=+Z  
{ -=n!k^?lK  
if(!fileSplitterFetch.bDownOver) EpTc{  
{ Rl_1g`84  
breakWhile = false; j3S!uA?  
break; ~mZ[@Z  
} ~S<}q6H.  
} 9yu#G7  
if(breakWhile) 'j?
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break; Hn/V*RzQ  
uc\G)BN  
N/1xc1$SB  
//count++; l*Fp}d.  
//if(count>4) dKevhm)R"  
// siteStop(); :bCswgd[  
} FuAs$;  
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System.err.println("文件下载结束！"); &g=6K&a$a  
} AbQnx%$u  
catch(Exception e){e.printStackTrace ();} U.=TjCW  
} |Qpd<L  
dZddoz_  
] pv!Ll  
//获得文件长度 rKTc6h:)  
public long getFileSize() y>cT{)E$  
{ -vh\XO  
int nFileLength = -1; mR#"ng  
try{ @Hr1.f  
URL url = new URL(siteInfoBean.getSSiteURL()); kLXa1^Lq  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); L"uidd0(g  
httpConnection.setRequestProperty("User-Agent","NetFox"); e5w0}/yW/  
[Kb)Q{=)  
%/}d'WJR  
int responseCode=httpConnection.getResponseCode(); d6zq,x!
cI  
if(responseCode>=400) %][zn$aa|  
{ 9U@>&3[v  
processErrorCode(responseCode); <W^>:!?w  
return -2; //-2 represent access is error ^e8
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} w;kiH+&  
&
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z)R\WFBW  
String sHeader; RF~c/en  
#8%~u+"N  
821 6_Qm  
for(int i=1;;i++) P` Gb}]rW  
{ 0OnqKgf  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }_Y\6fcd  
//Utility.log(in.readLine()); ' R= OeH  
sHeader=httpConnection.getHeaderFieldKey(i); M{=p0?X  
if(sHeader!=null) &$h#9  
{ dd@ D s  
if(sHeader.equals("Content-Length")) vtzbF1?O  
{ 3=0b  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); UY)Iu|~0b  
break; :Z6l)R+V  
} xo(>nFjo  
} WpkCFp  
else Hx9lQ8  
break; @[5]?8\o  
} /1hcw|cfC  
} BtQqUk#L2  
catch(IOException e){e.printStackTrace ();} Lf;Uv[^c  
catch(Exception e){e.printStackTrace ();} |9)y<}c5oM  
_1jeaV9@  
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Utility.log(nFileLength); w3Dqpo8E  
n ,@ge
 
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return nFileLength; -(E-yCu  
} Q.fD3g  
+X>Aj=#  
x139Ckn  
//保存下载信息（文件指针位置） ciN*gwI)  
private void write_nPos() ko~e*31_E  
{ JNI&]3[C>?  
try{ xfqU atC  
output = new DataOutputStream(new FileOutputStream(tmpFile)); zB6&),[,v  
output.writeInt(nStartPos.length); 9"dZ4{\!  
for(int i=0;i<nStartPos.length;i++) //#]CsFiP  
{ !!])~+4pP  
// output.writeLong(nPos); d81[hT}q  
output.writeLong(fileSplitterFetch.nStartPos); h|EHK!<"8  
output.writeLong(fileSplitterFetch.nEndPos); x`K"1E{2  
} '~xjaa;.  
output.close(); u}jC$T>2%6  
} 7[M@;$  
catch(IOException e){e.printStackTrace ();} z~jk_|?|?  
catch(Exception e){e.printStackTrace ();} &qm:36Y7Xg  
} Eq5X/Hx  
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//读取保存的下载信息（文件指针位置） {dvsZJj  
private void read_nPos() n&E/{o(  
{ eM^Y  
try{ "gXvnl  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #aadnbf  
int nCount = input.readInt(); bFfDaO<k  
nStartPos = new long[nCount]; Rts}y:44  
nEndPos = new long[nCount]; UJ&gm_M+kL  
for(int i=0;i<nStartPos.length;i++) ASr3P5/  
{ x' 3kHw  
nStartPos = input.readLong(); %;O# y3,  
nEndPos = input.readLong(); okBaQH2lUl  
} B,A\/%<  
input.close(); '~pZj"uy  
} ^!K 8nW{*  
catch(IOException e){e.printStackTrace ();} E{'\(6z_  
catch(Exception e){e.printStackTrace ();} J*qo3aJjE  
} / KKA/  
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private void processErrorCode(int nErrorCode) B(pHo&ox  
{ U> {CG+X  
System.err.println("Error Code : " + nErrorCode); I!~3xZ  
} QaAMiCZFR  
^K!R4Y4t  
;Y$d!an0  
//停止文件下载 )GJlQ1x  
public void siteStop() z_:r&UP`"  
{ s1zkkLw`*  
bStop = true; :LD+B1$y  
for(int i=0;i<nStartPos.length;i++) m8&
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fileSplitterFetch.splitterStop(); AKAxfnaR  
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} ns&(
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} `u7twW*U2  
//负责部分文件的抓取 Ap`D{u/  
**FileSplitterFetch.java ~h444Hp=  
*/ \3cg\Q+~  
package NetFox; OLDEB.@  
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import java.io.*; -V}ZbXJD  
import java.net.*; &fifOF#[e  
[&{NgUgu"  
21\?FQrz  
public class FileSplitterFetch extends Thread { P)hawH=  
x_x|D|@wM  
9q"G g?  
String sURL; //File URL h>"Z=y  
long nStartPos; //File Snippet Start Position cP8@'l@!  
long nEndPos; //File Snippet End Position Ijs=4f  
int nThreadID; //Thread's ID 1)!]zV  
boolean bDownOver = false; //Downing is over GoG_4:^#h  
boolean bStop = false; //Stop identical $I90KQB\_  
FileAccessI fileAccessI = null; //File Access interface A|P `\_  
b'4r5@GO  
Td![Id  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 20mZ{_%  
{ jp-]];:aPJ  
this.sURL = sURL; Ji:0J},m  
this.nStartPos = nStart; }/Y)^  
this.nEndPos = nEnd; 8?k.4{?  
nThreadID = id; B4;P)\2  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 5>M@ F0  
} < nyk:
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public void run() m{0u+obi&w  
{ JT 5+d ,  
while(nStartPos < nEndPos && !bStop) , -S n  
{ ~8G cWy6  
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try{ )1]LoEdm`  
URL url = new URL(sURL); h3kBNBI )  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =|bW >y  
httpConnection.setRequestProperty("User-Agent","NetFox"); eR5+1b  
String sProperty = "bytes="+nStartPos+"-"; nB86oQ/S  
httpConnection.setRequestProperty("RANGE",sProperty); 1V1T1  
Utility.log(sProperty); !)'|Y5
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69/qH_Y  
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InputStream input = httpConnection.getInputStream(); Jl,\^)DSw  
//logResponseHead(httpConnection); ]mvVX31T  
iMOf];O)  
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byte[] b = new byte[1024]; fT_swhIO  
int nRead; Qmn'G4#@E  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 'P~6_BW  
{ (ZuV5|N  
nStartPos += fileAccessI.write(b,0,nRead); `G.:G/b%H  
//if(nThreadID == 1) <2RxyoDL6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); AkRZUj\  
} _k.gVm  
60Obek`  
YiPp#0T[Gx  
Utility.log("Thread " + nThreadID + " is over!"); J*O$)K%Hx  
bDownOver = true; 1Du9N[2'P  
//nPos = fileAccessI.write (b,0,nRead); b1qli
5  
} BXo9s~5Q  
catch(Exception e){e.printStackTrace ();} q9"~sCH  
} Fgg4QF  
} _d/ZaCx'i  
,@*`2I>`  
{p@uj_pS  
//打印回应的头信息 j\8'P9~%  
public void logResponseHead(HttpURLConnection con) EM.rO/qcW  
{ uDi#a~m@  
for(int i=1;;i++) %uLyL4*L(p  
{ 9CTvG zkw  
String header=con.getHeaderFieldKey(i); $U/_8^6B0  
if(header!=null)  !#8=tO  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4Vi&Y')f  
Utility.log(header+" : "+con.getHeaderField(header)); q! U
'DDEP  
else 7?JcB?G4  
break; }D eW2Jp  
} j>OB<4?.+  
} /I&b5Vp  
=Z(#j5TGvH  
iP~dH/B|v  
public void splitterStop() 15FGlO<<  
{ 7'xds  
bStop = true; ,W/D0  
} S+YbsLf  
~cEr<mzR  
mDp|EXN  
} Z;JZ<vEt92  
9#@CmiIhy  
vXM``|  
/* 3M&75OE  
**FileAccess.java L&nGjC+Lr  
*//文件访问(定位，写) VCvqiHn  
package NetFox; oWUDTio#[  
import java.io.*; {m%X\s;ni  
XP-4=0zd  
wfrWpz=FO  
public class FileAccessI implements Serializable{ ?RD)a`y51  
S[ ,r.+  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C&'Y@GE5  
RandomAccessFile oSavedFile; {XNu4d9w(  
long nPos; 8Cr?0Z  
q}["Nww-  
jTx,5s-  
public FileAccessI() throws IOException [Pt5c6L:  
{ qlg~W/  
this("",0); {9Op{bZ  
} :I}_  
f6P5J|'  
g3%t+>$*  
public FileAccessI(String sName,long nPos) throws IOException rXz,<^Hmj  
{ Ucnit^,  
oSavedFile = new RandomAccessFile(sName,"rw"); !Jj=H()}  
this.nPos = nPos; ngJES`0d  
oSavedFile.seek(nPos); oB$D&  
} rkl/5z??  
|7I.DBjR;  
Bv |Z)G%RR  
public synchronized int write(byte[] b,int nStart,int nLen) |JL47FR  
{ ]eq3cwR[|  
int n = -1; C6eon4Ut  
try{ [J+K4o8L<A  
oSavedFile.write(b,nStart,nLen); "t"=9:_t  
n = nLen; L$x/T3@  
} `#X{
.  
catch(IOException e) yREO
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{ n6nwda  
e.printStackTrace (); c"J(? 1O  
} %;PPu$8K9  
W3K"5E0ck  
YAZ=-@]`\  
return n; bct&ge7YX  
} [M2,bc8SJV  
p$@=N6)I.k  
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} _wf
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9bXU!l[  
}~-)31e'`  
/*
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**SiteInfoBean.java -zz9k=q  
*/ h3xX26l  
package NetFox; 4#=!VK8ZH  
Xb3vvHdI  
eeb8v:4  
public class SiteInfoBean { # dxlU/*  
|_~BV&g,N  
$zz=>BOk  
private String sSiteURL; //Site's URL .?S#DS )  
private String sFilePath; //Saved File's Path sa+:c{  
private String sFileName; //Saved File's Name AJ:@c7:eS  
private int nSplitter; //Count of Splited Downloading File $b$r,mc  
yZFvpw|g  
tQJ@//C\z  
public SiteInfoBean() +.\JYH=yEr  
{//nSplitter的缺省值为5 v-[|7Pg}Z  
//default value of nSplitter is 5 OG 5n9sx  
this("","","",5); rf1nC$Sop  
} ;Xgy2'3  
g)&-S3\  
:N)7S
YQT  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) INzQ0z-z  
{ !1"~tA!+p=  
sSiteURL= sURL; `U`Z9q5-  
sFilePath = sPath; 9LJ/m\bi  
sFileName = sName; =4JVUu~Z  
this.nSplitter = nSpiltter; +Mm0
bqNN  
4b3p,$BWS  
<k^9l6@  
} WM=kr$/3  
x'JfRz  
-07(#>  
public String getSSiteURL() B{1+0k  
{ 6x/ X8zu  
return sSiteURL; 6nGDoW#  
} E4y"$U%.  
! 2Y, a  
l/rhA6kEU  
public void setSSiteURL(String value)
gYzKUX@  
{ R?|_`@@A  
sSiteURL = value; N}FG%a  
} !FpMO`m  
4 <]QMA0
 

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public String getSFilePath() }>frK#S  
{ \wDOE(>  
return sFilePath; nI_Zk.R  
} p-KuCobz]  
29Q5s$YD@  
R#\8jvv
 
public void setSFilePath(String value) n{'
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{ }.b[az\T  
sFilePath = value; H V  
} Y@.JW  
i,yK&*>JJ  
$V~%$  
public String getSFileName() Fx3VQ'%J  
{ s.GhquFCrU  
return sFileName; '{oe}].,
 
} Gh{k~/B  
eEc;w#  
5&9(d_#H  
public void setSFileName(String value) {8B\-LUR  
{ J$WIF&*0@  
sFileName = value; =$`DBLX   
} >2g CM  
? ! 1uw  
F~l3?3ZV  
public int getNSplitter() ?ST}0F00}  
{ [#R%jLEJ2  
return nSplitter; 1@nR.v"$  
} RXWjFv~/  
\ I?;%  
x(=kh%\;  
public void setNSplitter(int nCount) ap6Vmp  
{ dU&.gFw1  
nSplitter = nCount; )E[5lD61  
} n3|~X/I  
} ZXUe4@qfl  
l E&hw  
3mm`8!R  
/* 5W{>5.Arx)  
**Utility.java ~y|%D;  
*/ A|>C3S  
package NetFox; q90S>c,  
NI^Y%N  
lMm-K%(2  
public class Utility { &%*S  
MW4dPoa  
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public Utility() 93!a  
{ X ]a>  
.y\HQ^j  
Maa.>2v<  
} rL,)Tc|"  
YwF6/JA0^  
//线程睡眠 v;RQVH;,  
public static void sleep(int nSecond) KqS2  
{ h?ia4
t  
try{ +I Ze`M%n  
Thread.sleep(nSecond); -y\N9  
} eLC&f}  
catch(Exception e) <#s-hQ  
{ O?2
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e.printStackTrace (); n7MS{`  
} Asn0&Ys4  
} Gqia@>T4*N  
W?l .QQk  
//日志 vfbe=)}[  
public static void log(String sMsg) K4F!?#  
{ ~lF lv+,%  
System.err.println(sMsg); & 9]KkY=  
} t~a$|( 9  
.y0]( h  
Ffxk] o&%c  
public static void log(int sMsg) k0YsAa#6V  
{ hL3,/^;E,  
System.err.println(sMsg); 5{u6qc4FW  
} G4{qWa/  
} 2?r8>#_*  
r2](~&i2  
a:|4q  
/* U.)G#B  
**TestMethod.java !}PFiT^  
*/ GY",AL8f  
package NetFox; kI
fb!  
\G=E%aK  
dI 5sqM:  
public class TestMethod { /-hF<oNQ  
/SUV'J)  
nM; G; T  
public TestMethod() 28)TXRr-  
{ ///xx/weblogic60b2_win.exe b"Mq7&cf  
try{ #VOjnc/rW  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (wlsn6h  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); wrO>#`Z  
SiteFileFetch fileFetch = new SiteFileFetch(bean); vW{cBy  
fileFetch.start(); tT8jC:oVa  
} .#:,j1L"53  
catch(Exception e){e.printStackTrace ();} L~oFW'  
y{{EC#  
n>E*g|a  
} R_qo]WvR;  
,SyUr/D  
!U#++Zig%  
public static void main(String[] args) x7@WWFF>  
{ r~}}o o4K  
new TestMethod(); )*A,L%  
} '<0q"juXE  
} q%k+x)  
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