http断点续传简单实现（java)

/* l{V(Y$xp3  
**SiteFileFetch.java ~)5k%?.  
*/ sO)!}#,   
package NetFox; zhU^~4F  
import java.io.*; .G|U#%"6x  
import java.net.*; o^u}(wZ{  
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public class SiteFileFetch extends Thread { mHNqzdaa  
~~#/jULbV  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ZV[-$  
long[] nStartPos; //开始位置 r1sA^2g.  
long[] nEndPos; //结束位置 XL(2Qk  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 tz2$j@!=  
long nFileLength; //文件长度 /q^_ 'Lp  
boolean bFirst = true; //是否第一次取文件 h\8bo=  
boolean bStop = false; //停止标志 j)}TZx4~  
File tmpFile; //文件下载的临时信息 M*F`s&vM  
DataOutputStream output; //输出到文件的输出流 ' &Nv|v\V  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） +sXnC
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public SiteFileFetch(SiteInfoBean bean) throws IOException ^k!u  
{ Hlj3z3  
siteInfoBean = bean; M2nZ,I=l  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 'A/f>W  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Qe=eer~jI  
if(tmpFile.exists ()) -i4hJC!3  
{ Qq\hD@Z|  
bFirst = false; U"K%ip:Wd  
read_nPos(); +b{tk=Q:  
} &9xcP.3  
else [8[`V)b  
{ fjS#  
nStartPos = new long[bean.getNSplitter()]; kFi=^#J{  
nEndPos = new long[bean.getNSplitter()]; 8+~'T|  
} ;5}"2hU>  
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"=0JYh)%_  
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} NaeG)u#+  
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public void run() QB7^8O!<  
{ S#|5&SR  
//获得文件长度 
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//分割文件 &-|(q!jm  
//实例FileSplitterFetch a6g+"EcH#'  
//启动FileSplitterFetch线程 r D|Bj(X8  
//等待子线程返回 AaJz3oncJ  
try{ 1@`mpm#Y  
if(bFirst) Fw6x (j"  
{ pbqJtBBDDS  
nFileLength = getFileSize(); do@BJWo  
if(nFileLength == -1) @FuX^Q.[  
{ _?9|,  
System.err.println("File Length is not known!"); C6:; T%  
} ra{HlB{  
else if(nFileLength == -2) >orDw3xC  
{ h>n<5{zqM  
System.err.println("File is not access!"); xQ8?"K;iX  
} \eS-wO7%  
else _({K6adb  
{ _^Q =n>G  
for(int i=0;i<nStartPos.length;i++) 1$uO%  
{ y?V#LW[^E  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); RZI4N4o  
} (M,*R v  
for(int i=0;i<nEndPos.length-1;i++) u]t#Vf-$u  
{ o&rNM5:  
nEndPos = nStartPos[i+1]; )n$RHt+:>  
} zA&]#mc  
nEndPos[nEndPos.length-1] = nFileLength; WO{9S%ck  
} h?&S*)1  
} ],Y+|uX->  
gOn^}%4.I  

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//启动子线程 *iujJi  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]q@W(
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for(int i=0;i<nStartPos.length;i++) <{A|Xs  
{ qF4pTQf  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), YnX6U1/^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), I#](mRJ6  
nStartPos,nEndPos,i); gz`P~7-w:  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F0+@FS0  
fileSplitterFetch.start(); _<;westq  
}  c|~f[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8Sg:HU\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); tfq;
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \ dZD2e4  
nEndPos = " + nFileLength); qeoj
  
// fileSplitterFetch[nPos.length-1].start(); "z ;ky8  
;O *o  
GZNfx8zsY+  
//等待子线程结束 m*H6\on:  
//int count = 0; aZYs?b>Gm  
//是否结束while循环 mX QVL.P\  
boolean breakWhile = false; 5\P3JoH:Yg  
~er4w+"  
di#:KW  
while(!bStop) NFlrr*=t>  
{ atjrn:X  
write_nPos(); )\0LxsZ  
Utility.sleep(500); tU(vt0~b  
breakWhile = true; EyPF'|Qtn  
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for(int i=0;i<nStartPos.length;i++) ;PG,0R`Z;  
{ xouy|Nn
'  
if(!fileSplitterFetch.bDownOver) <LOas$
 
{ _;`g*Kx  
breakWhile = false; ]iVoF N}^  
break; Rac4a@hZ  
} # >L^W7^  
} *heX[D &>)  
if(breakWhile) FVS@z5A8<=  
break; D}:M0EBS  
+G<9|-  
dnUiNs8  
//count++; d(j|8/tpA  
//if(count>4) :ODG]-QF  
// siteStop(); {w|KWGk2  
} B3iU#  
9W@Tf  
9x9~u8j
 
System.err.println("文件下载结束！"); 9='=wWW  
} p}R3AJ  
catch(Exception e){e.printStackTrace ();} qox31pnS  
} i2+vUl|;Z  
>6zXr.  
]NgEN  
//获得文件长度 G9i?yd4n=B  
public long getFileSize() (3M7RpsL@  
{ U `<?~Bz  
int nFileLength = -1; Fl&Z}&5p  
try{ 6N.+  
URL url = new URL(siteInfoBean.getSSiteURL()); ti^msC8e  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \LZVazXD  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^zVBS7`J  
#-Nc1+gu  
>@NGX-gp  
int responseCode=httpConnection.getResponseCode(); ![#>{Q4i  
if(responseCode>=400) Rt10:9Kz$  
{ 3"J85V%h]n  
processErrorCode(responseCode); l\{{iAC]I  
return -2; //-2 represent access is error -?&s6XA%#  
} 5 NdIbC  
iH"
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String sHeader; O
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for(int i=1;;i++) KQ(7%W  
{ F-2&P:sjQ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ' Zmslijf  
//Utility.log(in.readLine()); b#[7A  
sHeader=httpConnection.getHeaderFieldKey(i); ~}fQ.F*7R  
if(sHeader!=null) q-)Ynp4'  
{ ~)&im.Q4  
if(sHeader.equals("Content-Length")) N3}jLl/  
{ zV8^Hxl  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?h4Rh0rkX  
break; %1oG<s  
} $9Yk]~  
} 17{$D,P  
else 4(FEfde=  
break; jvfQG:F }  
} QL4BD93v  
} #b?)fqRJL  
catch(IOException e){e.printStackTrace ();} 7-Yn8Gq  
catch(Exception e){e.printStackTrace ();} RY]Vo8  
;_vo2zl1  
9:tn!<^=I  
Utility.log(nFileLength); #fR~7KR  
o1(?j}:c|  
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return nFileLength; HQOz  
} /Sag_[i  
Y +9OP  
j\S}TaH0e  
//保存下载信息（文件指针位置） };=44E'7  
private void write_nPos() CnA
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{ AT%@T|  
try{ 4Cdl^4(LT  
output = new DataOutputStream(new FileOutputStream(tmpFile)); !{, `h<  
output.writeInt(nStartPos.length); Htu}M8/4  
for(int i=0;i<nStartPos.length;i++) IT\lkF2  
{ ADQ#qA,/  
// output.writeLong(nPos); Q7-d]xJ^  
output.writeLong(fileSplitterFetch.nStartPos); x.OCE`  
output.writeLong(fileSplitterFetch.nEndPos); t$W~X~//  
} R%Y#vUmBV{  
output.close(); ;.<0lnV  
} $ }D9)&f;  
catch(IOException e){e.printStackTrace ();} yxt`  
catch(Exception e){e.printStackTrace ();} CkJ\v%JAW  
} @3:oo /;  
A!&hjV`  
OAhCW*B  
//读取保存的下载信息（文件指针位置） bq<DW/  
private void read_nPos() >x$.mXX{  
{ f*}H4H EO  
try{ jZ8#86/#{  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1hQeuG  
int nCount = input.readInt(); tb@&!a$`?  
nStartPos = new long[nCount]; .;&1"b8G  
nEndPos = new long[nCount]; psHW(Z8G  
for(int i=0;i<nStartPos.length;i++) UFox
v)  
{ tL!R^Tf  
nStartPos = input.readLong(); C;&44cU/]  
nEndPos = input.readLong(); /v,H%8S  
} ~J Xqyw}  
input.close(); p+F{iMC  
} s}pn5zMp:8  
catch(IOException e){e.printStackTrace ();} ,?Bo x  
catch(Exception e){e.printStackTrace ();} ~A5MzrvIO2  
} DfNX@gbo  
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Jt3]'Nr04@  
private void processErrorCode(int nErrorCode) 7fg +WZ  
{ _26~<gU8  
System.err.println("Error Code : " + nErrorCode); (KF=v31_m  
} ]^63n/Twj  
+4,v.B@  
:i4>&4j  
//停止文件下载 _k,/t
10  
public void siteStop() 6] ~g*]T  
{ I<'wZJRRa  
bStop = true; !\0U
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for(int i=0;i<nStartPos.length;i++) l }i .  
fileSplitterFetch.splitterStop(); ;c-J)Ky  
MU; L7^  
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} Uo
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} 0pSqk/  
//负责部分文件的抓取 2^}E!(<  
**FileSplitterFetch.java g)<t=+a  
*/ F|3 =Cl  
package NetFox; @@,
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:CQ-?mT^LA  
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import java.io.*; ~ cKmf]  
import java.net.*; *)V1Sd#m  
Z>)(yi9+  
7n-;++a5]  
public class FileSplitterFetch extends Thread { D=w5Lks  

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~"E@do("  
String sURL; //File URL rI\G&OqpP  
long nStartPos; //File Snippet Start Position HbRDa  
long nEndPos; //File Snippet End Position ~v2E<S3  
int nThreadID; //Thread's ID *20$u% z2  
boolean bDownOver = false; //Downing is over j0p'_|)(  
boolean bStop = false; //Stop identical /e^q>>z  
FileAccessI fileAccessI = null; //File Access interface ?F@0"qi  
6n{`t/  
ay\e#)  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException X\r?g  
{ Jon<?DQj  
this.sURL = sURL; m'))prl  
this.nStartPos = nStart; 1rr\l`  
this.nEndPos = nEnd; nQ/R,+6h  
nThreadID = id; q;dg,Om  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Pa.D+  
} cr{;gP  
6R%Ra  
(p2jigP7a[  
public void run() n+Ia@$|m  
{ Oy:;v7  
while(nStartPos < nEndPos && !bStop) Y<'T;@  
{ |U*wM
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:27GqY,3sK  
try{ -lKk.Y.}r  
URL url = new URL(sURL); Jww LAQ5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ZGUhje!  
httpConnection.setRequestProperty("User-Agent","NetFox");
jY>BU&  
String sProperty = "bytes="+nStartPos+"-"; T}ZUw;}BL  
httpConnection.setRequestProperty("RANGE",sProperty); g1JBssw&m  
Utility.log(sProperty); 481SDG[b  
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InputStream input = httpConnection.getInputStream(); B'( /W@  
//logResponseHead(httpConnection); D<=:9  
q[l!kC+Eh  
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byte[] b = new byte[1024]; ;naD`([  
int nRead; {5
tb.{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >z'kCv
  
{  ~yQby&s  
nStartPos += fileAccessI.write(b,0,nRead); #HjiE  
//if(nThreadID == 1) 4{?Djnh  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); lkNaSz[  
} %F'*0<  
}%K)R5C  
D -Goi-4  
Utility.log("Thread " + nThreadID + " is over!"); ? Xb8B5  
bDownOver = true; Tw|cgB  
//nPos = fileAccessI.write (b,0,nRead); M_wqb'=  
} K:PPZ|  
catch(Exception e){e.printStackTrace ();} }P8@\2@=T  
} g4(vgWOW`  
} a}~Xns  
biTET|U`$  
 xZJ r
*  
//打印回应的头信息 [42vO  
public void logResponseHead(HttpURLConnection con) t2)S61Vr  
{ S+03aJNN#  
for(int i=1;;i++) 0'Kbh$LU  
{ 1&S34wJF  
String header=con.getHeaderFieldKey(i); a1lF8;[  
if(header!=null) {ZiZ$itf  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); qJY'"_Q{  
Utility.log(header+" : "+con.getHeaderField(header)); Nqih LUv  
else =.q Zgcg  
break; 9G7lPK  
} E;[ANy4L  
} mK!73<
p_  
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n9.` 5BH7/  
public void splitterStop() ?LP&VU1  
{ >"^H"K/T  
bStop = true; cVrses^yE  
} ich\`j[i  
h?f)Bt}ry  
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} o.qeF4\d6  
x.Sq2rw]V  
iHKWz)0  
/* jD@KG  
**FileAccess.java 'g<0MOq{  
*//文件访问(定位，写) mlolSD;7  
package NetFox; d|UK=B^x  
import java.io.*; F8(6P1}E  
-p|@Enn  
P I gbeP  
public class FileAccessI implements Serializable{ X@$x(Zc  
~HbZRDcJc  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 XdKhT618G  
RandomAccessFile oSavedFile; a?]Ow J  
long nPos; OidF{I*O  
XWQp-H.  
k_)H$*  
public FileAccessI() throws IOException MV"aO@  
{ F\1{bN|3  
this("",0); }nrl2yp:%  
} n !ty\E  
V,=V   

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public FileAccessI(String sName,long nPos) throws IOException :G
#>):  
{ -3 }  
oSavedFile = new RandomAccessFile(sName,"rw"); cC'{+j8-a  
this.nPos = nPos; pgg4<j_mn  
oSavedFile.seek(nPos); K8 Y/sHl  
} ht8%A 1|  
:cv_G;?  
PxENLQ3a=  
public synchronized int write(byte[] b,int nStart,int nLen) Q`#Y_N-h+  
{ '2+Rb7V  
int n = -1; i*`;/x'+  
try{ oi4tj.!J  
oSavedFile.write(b,nStart,nLen); *c}MI e'&  
n = nLen; D{~mJDUzK  
} 9o7E/wP  
catch(IOException e) Rn={:u4  
{ jBexEdH  
e.printStackTrace (); bqmOfGM  
} {9wBb`.n^  
#8.%YG  
Pyc/6~?  
return n; I~lX53D  
} ]m0MbA  
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`.PZx%=  
} ax7]>Z=%d"  
7T \}nX1  
CrHH Ob  
/* a}l^+  
**SiteInfoBean.java !@E=\Sm8EV  
*/ RH+3x7l  
package NetFox; 7o?6Pv%HJC  
fDo )~t*~  
(r_xs  
public class SiteInfoBean { "7_6iB&@<  
yE3g0@*  
mO$]f4}  
private String sSiteURL; //Site's URL &E.ckWf  
private String sFilePath; //Saved File's Path z@hlN3dg  
private String sFileName; //Saved File's Name Q8.SD p  
private int nSplitter; //Count of Splited Downloading File Q5'DV!0aSv  
6AgevyVG  
0tVZvXgTu  
public SiteInfoBean() =VkbymIZ4y  
{//nSplitter的缺省值为5 OZdiM&Zss  
//default value of nSplitter is 5 gf6<`+
/  
this("","","",5); D6!`p6r+  
} HpI[Af}l  
mq@2zE`.(  
@D%H-X  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Ct[{>asun  
{ ^S*~<0NQ'  
sSiteURL= sURL; aNgaV$|2a  
sFilePath = sPath; L1#z'<IO  
sFileName = sName; (xffU%C^  
this.nSplitter = nSpiltter; _uL{@(  
ffo{4er  
=\7
o@ 38  
} -~Kw~RX<(  
]Bw2>6W  
0sW=;R2  
public String getSSiteURL() Og
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{ /
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return sSiteURL; Sw~jyUEr  
} xMI4*4y(  
,yW BO  
w4Nm4To  
public void setSSiteURL(String value) [h7nOUL!  
{ CSx V^  
sSiteURL = value; U1<EAGo|  
} ]v7f9MC'\  
der'<Q.U:k  
UCzIOxp}  
public String getSFilePath() S0C 7'H%?#  
{ Y9fktg.  
return sFilePath; #N\kMJl$l  
} LU5e!bP  
!MoJb#B3^]  
t-gg,ttnA  
public void setSFilePath(String value) p b:mw$XQ7  
{ zSMNk AM  
sFilePath = value; Ndq|Hkd  
} ML?%s`   
e W&;r&26  
gZ6]\l]J{  
public String getSFileName() mZsftby}  
{ /Y("Q#Ueq  
return sFileName; )`?Es8uW  
} +$M%"=tk  
qQC<oR  
E,,)?^g  
public void setSFileName(String value) :eqDEmr>  
{ \"BoTi'2!  
sFileName = value; Vrl)[st!;I  
} ;pu68N(B  
C=L_@{^Rgb  
=E@wi?  
public int getNSplitter() t_1a.Jv  
{ k@nx+fO}P  
return nSplitter; kBYZNjSz  
} BG!;9Z{u  
1SoKnfz{6  
L<bZVocOb_  
public void setNSplitter(int nCount) Onoi^MDy  
{ NQzpgf|h  
nSplitter = nCount; uKF?UXc  
} Eyu]0+  
} "TB4w2?=  
+-~hl  
],vUW#6$N  
/* 6B 4Sd  
**Utility.java >
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*/ g'G%BX  
package NetFox; !<\"XxK+l  
@cNBY7=  
Cw1Jl5OVZ  
public class Utility { wWs<{ T  
't".~H_V  
*oLAO/)n  
public Utility() {B$cd?}  
{ gAt[kW< n  
gIv :<EJ9  
[v$_BS#u^3  
} J~7E8  
v%c r  
//线程睡眠 O8#}2  
public static void sleep(int nSecond) ZC+F*:$  
{ g7!P|  
try{ <1#v}epD#  
Thread.sleep(nSecond); 1.WdxMpW9  
} c$aTl9e  
catch(Exception e) (3YqM7cqt  
{ F#S^Q`  
e.printStackTrace (); udxLHs  
} J{8_4s!Xt>  
} 0&$+ CWSM  
R=ddQ:W6g  
//日志 P~nI6/r1  
public static void log(String sMsg) ]eA<  
{ (XYYbP  
System.err.println(sMsg); seWYY $$  
} 2Wz/s 0`  
NQefrof  
3vTX2e.w  
public static void log(int sMsg) IE*GF27n  
{ '@'~_BBZP  
System.err.println(sMsg); \z!*)v/{-  
} is&A_C7yg  
} s6<`#KFAg  
UEmNT9V  
S^|Uzc  
/* Y~]E6'Bz  
**TestMethod.java 3f9J!B`n  
*/ cQDn_Sjhi  
package NetFox; a x1  
)2T?Z)"hO  
V~-<VM6  
public class TestMethod { hY=#_r8  
"orZje9AC  
cQEK>aAd  
public TestMethod() A
P.WTFf  
{ ///xx/weblogic60b2_win.exe %0 (,f  
try{ j~!0n[F  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 3c] oU1GfF  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 'T@K$xL8  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \wRbhN  
fileFetch.start(); CU)'x E  
} ! 7,rz1s73  
catch(Exception e){e.printStackTrace ();} Th,15H DA  

v  P8.{$  
zp[Uh]-dMK  
} `-!t8BH  
F`,XB[}2  
'c[4-m3bg  
public static void main(String[] args) l +RT>jAmK  
{ J<dr x_gc  
new TestMethod(); -+4:} sD  
} ($:s}_<>s  
} dK|6p_  
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