http断点续传简单实现（java)

/* @z,*K_AKr  
**SiteFileFetch.java :F(9"L  
*/ U6j/BJT"  
package NetFox; &d^=siL  
import java.io.*; %$X\"  
import java.net.*; Xa,&ef&q  
^X?D#\  
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public class SiteFileFetch extends Thread { y?:dE.5p|  
*8A6Q9YT  
/^<en(0=P  
SiteInfoBean siteInfoBean = null; //文件信息Bean !D:k!  
long[] nStartPos; //开始位置 F@SG((`  
long[] nEndPos; //结束位置 *@M3p}',M  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 %J P!{mqj  
long nFileLength; //文件长度 Da,Tav%b  
boolean bFirst = true; //是否第一次取文件 8 njuDl  
boolean bStop = false; //停止标志 X#J6Umutm  
File tmpFile; //文件下载的临时信息 \lr/;-zP  
DataOutputStream output; //输出到文件的输出流 (cV  
rw u3Nb  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） *o4%ul\3Y|  
public SiteFileFetch(SiteInfoBean bean) throws IOException A~71i&  
{ ZgYZwc&-  
siteInfoBean = bean;  rz  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); &?<AwtNN  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _Z#eS/,O@  
if(tmpFile.exists ()) 8&(-8  
{ 4XG]z_+I  
bFirst = false; 
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read_nPos(); )/Y~6A9>  
} X>3^a'2,E  
else iJnh$jo  
{ Q1V2pP+=@  
nStartPos = new long[bean.getNSplitter()]; /~hbOs/ L  
nEndPos = new long[bean.getNSplitter()]; 2VYvO=KA  
} %C*^:\y  
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} .ZX2^)`XD  
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public void run() 9k`~x1Y)  
{ "$@,n7k  
//获得文件长度 \y~)jq:d"  
//分割文件 42@a(#z(U  
//实例FileSplitterFetch fValSQc!U  
//启动FileSplitterFetch线程 $ I<|-]u  
//等待子线程返回 #v/ry)2Y=  
try{ l>Av5g)  
if(bFirst) K-@bwB7~s  
{ M,..Kw/ }~  
nFileLength = getFileSize(); l2/@<0P  
if(nFileLength == -1) jgRCs.6  
{ o;;,iHu*  
System.err.println("File Length is not known!"); (,tHL  
} chLeq  
else if(nFileLength == -2) ~CFMIQ et  
{ Bz:0L1@,4a  
System.err.println("File is not access!"); K%2I
  
} NsmVddj  
else 3+ asP&n  
{ {3 o%d:  
for(int i=0;i<nStartPos.length;i++) H m8y]>$  
{ _LLshV3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); B9W/bJ6%  
} Mjw[:70  
for(int i=0;i<nEndPos.length-1;i++) ~d+O/:=K_  
{ .0 X$rX=  
nEndPos = nStartPos[i+1]; lC{L6&T  
} 04\Ta  
nEndPos[nEndPos.length-1] = nFileLength; FO^24p  
} ?*o;o?5s^  
} LDX y}hm)  
fLM.kCD?u  
+$~8)95<B  
//启动子线程 Zg
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; G5umeqYC  
for(int i=0;i<nStartPos.length;i++) n)CH^WHL&  
{ RpeBm#E2  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 'FxYMSZS$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), BvJ\x)  
nStartPos,nEndPos,i); ^0eO\wc?O  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }K;iJ~kD1  
fileSplitterFetch.start(); -
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} D(@SnI+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \E&thp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Zh? V,39  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", .h6Y<
E  
nEndPos = " + nFileLength); @Yarz1  
// fileSplitterFetch[nPos.length-1].start(); !Sfe{/$w  
@7X\tV.Z  
K*:Im#Q  
//等待子线程结束 1:5P%$?b  
//int count = 0; ]:!8 s\#  
//是否结束while循环 E6Q91Wz9f  
boolean breakWhile = false; QRiF!D)Nk  
5iv@@1c  
SZE`J:w  
while(!bStop) 4K'|DO|dH  
{ ZmP1C`>  
write_nPos(); oFn4%S:  
Utility.sleep(500); ~D_rZ&  
breakWhile = true; b<\GI7  
M;
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~QO< B2hS}  
for(int i=0;i<nStartPos.length;i++) .Nk
6  
{ 'Ye]eL,I\  
if(!fileSplitterFetch.bDownOver) F]0Jwm{  
{ WS5"!vz   
breakWhile = false; -BjEL;  
break; &gJW6<  
} 6ku8`WyoF  
} 9?!u2 o  
if(breakWhile) F*. /D~K  
break; Pgx+\;w"  
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"V:XhBG?  
//count++; NC;T( @  
//if(count>4) 'l8eH$  
// siteStop(); Z{ %Uw;d  
} JkJhfFV  
> `0| X  
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System.err.println("文件下载结束！"); [e1\A&T  
} DWdLA~'t  
catch(Exception e){e.printStackTrace ();} |<'10  
} &!4( 0u  
EO"=\C,  
<w;D$l}u  
//获得文件长度 PQQgDtiH  
public long getFileSize() P mC82"  
{ VBhE{4J  
int nFileLength = -1; ?3n=m%W,J*  
try{ Re7{[*Q4  
URL url = new URL(siteInfoBean.getSSiteURL()); +6uOg,;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }@3$)L%n_u  
httpConnection.setRequestProperty("User-Agent","NetFox"); :^K~t!@  
1RmBtx\<  
dPRtN@3  
int responseCode=httpConnection.getResponseCode(); z=u~]:.1O  
if(responseCode>=400) ^NcTWbs-T  
{ l;XUh9RF`A  
processErrorCode(responseCode); FU^Y{sbDg  
return -2; //-2 represent access is error /Ql6]8.P  
} VN?<[#ij  
1o(+rR<h9  
,I("x2  
String sHeader; bL+sN"Km  
nIG[{gGX  
Mp!2`4rD  
for(int i=1;;i++) XL=
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{ [;)~nPjI  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());  'Dnq+  
//Utility.log(in.readLine()); n})  
sHeader=httpConnection.getHeaderFieldKey(i); $&bU2]  
if(sHeader!=null) DrW/KU,{+(  
{ UzXDi#Ky  
if(sHeader.equals("Content-Length")) $4ka +nfU  
{ Pxap;;\  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); R%Kl&c  
break; t!NrB X  
} (q055y  
} AsV8k_qZL  
else GcPB'`!M  
break; L!`*R)
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} mI2|0RWI)l  
} SB5@\^  
catch(IOException e){e.printStackTrace ();} rHH#@Zx  
catch(Exception e){e.printStackTrace ();} rD_Ss.\^g  
~4l6unCI  
"X\q%%P=?  
Utility.log(nFileLength); =B1`R%t  
9t,aT!f  
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return nFileLength; FuIWiO(  
} Z#H@BWN7  
dP$y>%cB  
0%vixR52  
//保存下载信息（文件指针位置） L2:oZ&:u`J  
private void write_nPos() e,PQ)1  
{ %w;1*~bH  
try{ m~b#:4D3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0:~gW#lD  
output.writeInt(nStartPos.length); J+-,^8)  
for(int i=0;i<nStartPos.length;i++) K+(
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{ c`Lpqs`  
// output.writeLong(nPos); <h)deB+}  
output.writeLong(fileSplitterFetch.nStartPos); **"zDY*?W  
output.writeLong(fileSplitterFetch.nEndPos); #sozXz
a\G  
} ?14X8Mb8W_  
output.close(); cuJ/ Vc  
} ,:\zXESy4  
catch(IOException e){e.printStackTrace ();} RXIH(WiK  
catch(Exception e){e.printStackTrace ();} 5|{  t+u  
} r>n8`W  
18l~4"|fk  
fSm?27_  
//读取保存的下载信息（文件指针位置） 1"87EP   
private void read_nPos() _Eet2;9  
{ C`=`Ce~|d  
try{ UFSEobhg&5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); O:5ldI  
int nCount = input.readInt(); rElG7[+)p  
nStartPos = new long[nCount]; F5b]/;|  
nEndPos = new long[nCount]; p1[WGeV  
for(int i=0;i<nStartPos.length;i++) f)!{y>Q  
{  uhPIV
\  
nStartPos = input.readLong(); l%vhV&  
nEndPos = input.readLong(); >B|ofwm*  
} ulJ+:zwq$  
input.close(); / r`Y'rm  
} ZVC
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catch(IOException e){e.printStackTrace ();} JC1BUheeb  
catch(Exception e){e.printStackTrace ();} Y
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} sZ\i(eIU  
^^W`Lh%9
 
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private void processErrorCode(int nErrorCode) "'LOaf$X  
{ tFb|y+  
System.err.println("Error Code : " + nErrorCode); 2l;ge>DJ  
} L
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>xk:pL*o`  
u!156X?[eU  
//停止文件下载 &AkzSgP  
public void siteStop()  Wl}G[>P  
{ `pn-fk  
bStop = true; ixUiXP  
for(int i=0;i<nStartPos.length;i++) `K ~>!d_  
fileSplitterFetch.splitterStop(); mAtG&my)  
}1E_G  
]Y/pSwnV  
} crF9,p  
} I=Lj_UF4  
//负责部分文件的抓取 7i%P&oB  
**FileSplitterFetch.java Nc^b8& 2J  
*/ wZ#~+ }T  
package NetFox; DXw9@b  
}sm56}_  
3n=cw2FG  
import java.io.*; et7T)(k0  
import java.net.*; 4%W
n}@  
h_}BmJh_  
?7uStqa  
public class FileSplitterFetch extends Thread { YV>VA<
c  
ce-m)o/  
!3gpiQH{  
String sURL; //File URL |Cxip&e>  
long nStartPos; //File Snippet Start Position +=lcN~U2  
long nEndPos; //File Snippet End Position Y=#mx3.
 
int nThreadID; //Thread's ID L>K39z~,  
boolean bDownOver = false; //Downing is over n$Oky-P"  
boolean bStop = false; //Stop identical ^~hhdwu3a  
FileAccessI fileAccessI = null; //File Access interface _a:!U^4  
`~s,W.Eu4  
=Am*$wGI  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException D6@
4  
{ 7{6cLYl  
this.sURL = sURL; `dq3=  
this.nStartPos = nStart; blQzVp-  
this.nEndPos = nEnd; m$G?e9{  
nThreadID = id; 2v; 7ohK  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 D=Yag!1  
} ztt%l #  
k}owEBsn}  
\q)1TTnHS  
public void run() d}A2I  
{ rSFXchD/  
while(nStartPos < nEndPos && !bStop) mU0r"\**c3  
{ Ny&Fjzl  
4N^Qd3[d  
:j50]zLy{  
try{ +xu/RY_  
URL url = new URL(sURL); w[n>4?
"{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); DqC}f#  
httpConnection.setRequestProperty("User-Agent","NetFox"); `W;cft4  
String sProperty = "bytes="+nStartPos+"-"; E* DVQ3~  
httpConnection.setRequestProperty("RANGE",sProperty); wh[:wE]eX  
Utility.log(sProperty); @XSu?+s)  
=M km:'1r  
a(QZZq};S  
InputStream input = httpConnection.getInputStream(); hSf#;=9'  
//logResponseHead(httpConnection); $9u  

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byte[] b = new byte[1024]; P(gID  
int nRead; OrqJo!FEg{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2$/gg"g+  
{ dJ"xW;"  
nStartPos += fileAccessI.write(b,0,nRead); {83He@  
//if(nThreadID == 1) 1*Fvx-U'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); QR-R5XNT[  
} 9G\3hL]  
b"3T(#2<*  
R@{/$p:  
Utility.log("Thread " + nThreadID + " is over!"); zk_hDhg&'  
bDownOver = true; ~k<31 ez  
//nPos = fileAccessI.write (b,0,nRead); 7&S|y]$~  
} )-:f;#xJ  
catch(Exception e){e.printStackTrace ();} g5YsVp  
} *
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} q\Io6=39x  
#;KG6IE  
Nb,H8;
 
//打印回应的头信息 \:)o'-  
public void logResponseHead(HttpURLConnection con) _nCs$U  
{ j`&i4K:  
for(int i=1;;i++) ^Ypx|-Vu!  
{ C36.UZoc  
String header=con.getHeaderFieldKey(i); aG
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if(header!=null) 1H@rNam&  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )jZ=/xG  
Utility.log(header+" : "+con.getHeaderField(header)); lM]),}   
else 'C8=d(mR=m  
break; #?d#s19s  
} 0GR9C%"]  
} <("w'd}  
s7cyo ]  
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public void splitterStop() zNTu j p  
{ B*?PB]  
bStop = true; >+LgJo R  
} v\tbf  
7 QJcRZ[lU  
:^L]Da3  
} cNB$g )`  
$Lbe5d?\  
8qLgB   
/* _+Kt=;Y8  
**FileAccess.java 2g8P$+;  
*//文件访问(定位，写) `G5wiyH})  
package NetFox; ;Z~.54Pf{d  
import java.io.*; F0(Sv\<::  
eBRP%<=>D  
,^Srd20  
public class FileAccessI implements Serializable{ %H~gN9Vn#@  
#\;w
::  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 HP
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RandomAccessFile oSavedFile; NB#*`|qt  
long nPos; 2cL)sP}  
NKh{iSLm  
~"YNG?Rre  
public FileAccessI() throws IOException bHT@]`@@  
{ c\ *OId1{;  
this("",0); swgBPJ"?  
} {!?RG\EYN  
pNWp3+a'  
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public FileAccessI(String sName,long nPos) throws IOException Z|GkM5QH:  
{ Bj
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oSavedFile = new RandomAccessFile(sName,"rw"); 0e](N`  
this.nPos = nPos; ll09j Ef  
oSavedFile.seek(nPos); y5D?Bg|M  
} +E[
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w[G_w:$a  
Z69IHA[  
public synchronized int write(byte[] b,int nStart,int nLen) bbkI}d%(Ng  
{ >U/g*[>  
int n = -1; TAoR6aE  
try{ |;-r};  
oSavedFile.write(b,nStart,nLen); L2$L.@  
n = nLen; sYP@>tHC  
} MW>28  
catch(IOException e) j]D =\  
{ ,FVy:"FR  
e.printStackTrace (); W+S; Do  
} 0l@+xS;  
lM%fgyX  
-B(KQT,J  
return n; >D#}B1(!  
} X1dG'PQ  
GP'Y!cl  
:vT%5CQ  
} 3) 0~:  
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~B\:  
/* EC&,0i4n:  
**SiteInfoBean.java %.U{):lNx  
*/ {3Wc<&D C1  
package NetFox; k4rBS  
W (=B H  
"-:\-sMt{  
public class SiteInfoBean { .p}Kl$K]
 
/CE d14.  
T+D]bfjr&&  
private String sSiteURL; //Site's URL <~+  
private String sFilePath; //Saved File's Path N+75wtLy&  
private String sFileName; //Saved File's Name &/?jMyD@  
private int nSplitter; //Count of Splited Downloading File !l^AKn|  
~mU_`o  
kR(=VM JU  
public SiteInfoBean() O3Mv"Py%  
{//nSplitter的缺省值为5 nHrCSfK  
//default value of nSplitter is 5 ~]M"  
this("","","",5); +}/!yQtH  
} 59]9-1" +  
[1GEe
 
@NE#P&f  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) b\S}?{m5  
{ W2N7  
sSiteURL= sURL; #B9[U} 8  
sFilePath = sPath; Th^#H  
sFileName = sName; i8.[d5  
this.nSplitter = nSpiltter; &Qjl|2  
-P
&e4sV{  
L{p
g?#\yC  
} oy: MM  
2&URIQg*
J  
#{,IY03  
public String getSSiteURL() V/e_:xECC  
{ ]L^M7SKE6  
return sSiteURL; w%n]~w=8  
} ,2bAKa  
H/Q)zDP  
i@L2W>{P  
public void setSSiteURL(String value) /)T
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{ }}1Q<puM  
sSiteURL = value; V}-o):dI|  
} -~fI|A^  
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]'/]j  
public String getSFilePath() T_T{c+,Zd$  
{ zmRK%a(  
return sFilePath; Am4(WXVQ  
} 2,0F8=L  
(=rv `1  
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public void setSFilePath(String value) nDy=ZsK  
{ jF9CTL<  
sFilePath = value; YYW70k:  
} aM!#  
G- WJlu  
I_7EfAqg(  
public String getSFileName() ~#\#!H7  
{ F JhVbAMd  
return sFileName; !*6z=:J  
} KL]!E ~i  
4&fnu/,Z  
=i?,y+<  
public void setSFileName(String value) v19`7qgR(  
{ f34&:xz2U  
sFileName = value; >~~\==".  
} 926oM77  
K~T\q_ZPZ  
_xt(II   
public int getNSplitter() ku8c
)  
{ _<Yo2,1^  
return nSplitter; %WR"85  
} *`T&Dlt'8  
H_nJST<v`  
7+4"+C
A  
public void setNSplitter(int nCount) 8ZfIh   
{ 7:'>~>'  
nSplitter = nCount; c F]3gM  
} =
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} 5AU3s  
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oW6<7>1M7  
/* !H\GHA'DO]  
**Utility.java .+h pxZ  
*/ Qpf]3  
package NetFox; kH-b!  
0u2uYiE-l  
yVzg<%CR^  
public class Utility { hATy3*4  
|LH*)GrD*t  
uf]$@6)  
public Utility() vyGLn  
{ ,5*xE\9G  
uiA:(2AQ  
5T#D5Z<m  
} RQNi&zX/  
4LJ}>e  
//线程睡眠 Q}]
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public static void sleep(int nSecond) j],.`Y  
{ tta0sJ8i  
try{ tdF[2@?+  
Thread.sleep(nSecond); F:GKnbY  
} ~la04wR28  
catch(Exception e) >Fk
`h=Wd  
{ QC,(rB  
e.printStackTrace (); KdsvZim0>  
} "e<. n  
} z}8L}:  
:=v{inN  
//日志 #q.G_-H4J@  
public static void log(String sMsg) b)^ZiRW``  
{ u?Mu*r?  
System.err.println(sMsg); $OoN/^
kv  
} ld:alEo  
~ O=|v/]  
)^f Q@C8  
public static void log(int sMsg) R9G)X]  
{ G>>u#>0  
System.err.println(sMsg); =c^=Yvc7U  
} WVK-dBU  
} l{m~d!w`a  
MPy][^s!  
E9 q;>)}  
/* D#}Yx]Q1  
**TestMethod.java Am0C|(#Xm  
*/ q*TKs#3  
package NetFox; Ab<Ok\e5  
[j U  
lILtxVBO2o  
public class TestMethod { F>(#Af9  
BG0Mj2  
v/.h%6n?  
public TestMethod() u;qMo`-  
{ ///xx/weblogic60b2_win.exe U*"cf>dB(  
try{ vD9D:vK  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); HKN"$(Q  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); qpqz. {\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 7qK0!fk5  
fileFetch.start(); k|Yv8+XT  
} f.)F8!!  
catch(Exception e){e.printStackTrace ();} Cy:`pYxhd  
@Qjl`SL%O^  
slv
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} e -]c  
&dDI*v+  
_Ge^ -7  
public static void main(String[] args) 5=h'!|iY  
{ 1$D`Z/N"A  
new TestMethod(); ;s.5\YZ"k  
} Q1\k`J  
} $"{3yLg  
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