http断点续传简单实现（java)

/* LP2~UVq  
**SiteFileFetch.java  F B]Y~;(  
*/ ZT0\V ]!B  
package NetFox; 1[FN: hm  
import java.io.*; 02;jeZ#z  
import java.net.*; acd[rjeT  
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public class SiteFileFetch extends Thread { O0 'iq^g  
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SiteInfoBean siteInfoBean = null; //文件信息Bean g'"~'  
long[] nStartPos; //开始位置 mQ"~x]  
long[] nEndPos; //结束位置 5ZCu6A  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Q:}]-lJg  
long nFileLength; //文件长度 w#A)B<Y/"  
boolean bFirst = true; //是否第一次取文件 >)>f~>  
boolean bStop = false; //停止标志 -F5BJk  
File tmpFile; //文件下载的临时信息 djd/QA
fSC  
DataOutputStream output; //输出到文件的输出流 'Y38VOI%  
}vndt*F   
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ':*H#}Br-#  
public SiteFileFetch(SiteInfoBean bean) throws IOException U3(+8}Q  
{ Ji4p6$ .j-  
siteInfoBean = bean; 7J'%;sH  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Kk3+ ]W<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $8tk|uh  
if(tmpFile.exists ()) !T6R[  
{ `4Yo-@iVP  
bFirst = false; `#""JTA"  
read_nPos(); oC0ndp~+&  
} X9x`i  
else FI.te3i?7  
{ H$![]Ujq  
nStartPos = new long[bean.getNSplitter()]; w~lH2U'k}  
nEndPos = new long[bean.getNSplitter()]; `7"="T~ *  
} lC<;Q*Y  
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} HC iRk1  
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public void run() x,B] J4  
{ m2]N%Y  
//获得文件长度 YWZ;@,W  
//分割文件 ImXYI7PL  
//实例FileSplitterFetch (W1$+X  
//启动FileSplitterFetch线程 <jh4P!\&j  
//等待子线程返回 ^<I(  
try{
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if(bFirst) w~Tg?RH:  
{ yw1&I^7  
nFileLength = getFileSize(); { I#>6  
if(nFileLength == -1) zPt<b!q  
{ &Ok1j0~~  
System.err.println("File Length is not known!"); t.P@Ba^  
} FnvpnU",  
else if(nFileLength == -2) c^}y9% 4c  
{ ,54z9F`  
System.err.println("File is not access!"); :i.@d?  
} qb>ULP0  
else W[2]$TwT  
{ |UTajEL  
for(int i=0;i<nStartPos.length;i++) ;(C<gt,r}  
{ #U:|
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); oE '
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} *HoRYCL  
for(int i=0;i<nEndPos.length-1;i++) bRAD_  
{ (&}[2pb!  
nEndPos = nStartPos[i+1]; :[0 R F^2}  
} (b25g!  
nEndPos[nEndPos.length-1] = nFileLength; Q-7?'\h  
} Iz0$T.T  
} 25>R^2,LiE  
~I||"$R  
eiMP:  
//启动子线程 '1mk;%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; .a4,Lr#q.  
for(int i=0;i<nStartPos.length;i++) |ADf~-AY  
{ dl4n-*h  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }3 xkA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4=Th<,<  
nStartPos,nEndPos,i); c p"K?)  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u)@:V)z  
fileSplitterFetch.start(); A \/~u"Y  
} `~XksyT  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jQ{ @ol}n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); h>pu^ `hk  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", D{(}&8a9  
nEndPos = " + nFileLength); ajSB3}PN  
// fileSplitterFetch[nPos.length-1].start(); 0qS/>u*  
;,77|]<XE  
n0KpKH<&  
//等待子线程结束 UarLxPQ  
//int count = 0; 8pnD6Lp>  
//是否结束while循环 ?UsCSJ1V  
boolean breakWhile = false; 50
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,U""m7   
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while(!bStop) ad}8~6}_&  
{ , >7PG2 a  
write_nPos(); W&hW N9iR  
Utility.sleep(500); riW9l6s'  
breakWhile = true; .i*oZ'[X  
;"M6}5dQ4  
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for(int i=0;i<nStartPos.length;i++) d*8*9CpO:  
{ <tvLKx  
if(!fileSplitterFetch.bDownOver) Jl_W6gY"Z  
{ 6Z|h>H5a  
breakWhile = false; 7qqzL_d>  
break; P!79{8  
} qur2t8gnxq  
} UF-&L:s[  
if(breakWhile) yksnsHs}d  
break; 7(}'
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//count++; }U8v ~wcd  
//if(count>4) %,WH*")  
// siteStop(); yeiIP  
} CHGa_  
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PA'&]piPl:  
System.err.println("文件下载结束！"); K 4GuOl  
} (RFH.iX  
catch(Exception e){e.printStackTrace ();} VpJKH\)Rt(  
} x3i}IC  
sT;wHtU  
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//获得文件长度 j&X&&=   
public long getFileSize() e*Wk;D&  
{ wp@_4Iq1$  
int nFileLength = -1; 8?iI;(  
try{ 3RaW\cWzg  
URL url = new URL(siteInfoBean.getSSiteURL()); ~B|m"qY{i  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); J
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httpConnection.setRequestProperty("User-Agent","NetFox"); x|m9?[ !_  
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int responseCode=httpConnection.getResponseCode(); >e {1e  
if(responseCode>=400) c:m=9>3  
{ :^ywc O   
processErrorCode(responseCode); 'S3<' X  
return -2; //-2 represent access is error 2VRGTx  
} t.8r~2(?  
:&wb+tV  
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String sHeader; <7]HM5h  
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N" L&Z4Z  
for(int i=1;;i++) fk,Vry  
{ e ymv/  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Rq}lW.<r  
//Utility.log(in.readLine()); \'Ae,q|w  
sHeader=httpConnection.getHeaderFieldKey(i); ynmjIQ  
if(sHeader!=null) <kFLwF?PM'  
{ [XY%<P3D  
if(sHeader.equals("Content-Length")) *:yG)J 3F  
{ }PJsPIa3j  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^
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break; kY$EK]s  
} ]P3m=/w  
} +7b8ye  
else aB6xRn9  
break; CIIjZ)T  
} 0FOB5eBR  
} tq59w  
catch(IOException e){e.printStackTrace ();} ;+wB!/k,  
catch(Exception e){e.printStackTrace ();} r+bGZ  
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Utility.log(nFileLength); m'NAM%$}J  

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return nFileLength; n- 2X?<_Z  
} W q<t+E[  
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+b-ON@9]J`  
//保存下载信息（文件指针位置） P{9:XSa%  
private void write_nPos() U:TkO=/
>:  
{ g.&B8e  
try{ C{bxPILw  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ~^obf(N`  
output.writeInt(nStartPos.length); Y]([K.I=  
for(int i=0;i<nStartPos.length;i++) FC1rwXL(  
{ ~Y/A]N86,  
// output.writeLong(nPos); C*2%Ix18+N  
output.writeLong(fileSplitterFetch.nStartPos); t.ulG *  
output.writeLong(fileSplitterFetch.nEndPos); W p)!G  
} ;NA5G:eQ  
output.close(); iI<c  
} zgGysjV  
catch(IOException e){e.printStackTrace ();} =c@hE'{
 
catch(Exception e){e.printStackTrace ();} ya&=UoI  
} mEJ7e#  
iL;V5|(sb  
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//读取保存的下载信息（文件指针位置） 9:{<:1?  
private void read_nPos() B!Wp=9)G  
{ ;$
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try{ \$_02:#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,w~3K%B4  
int nCount = input.readInt(); STnMBz7  
nStartPos = new long[nCount]; <~dfp  
nEndPos = new long[nCount]; 6vK`J"d{~D  
for(int i=0;i<nStartPos.length;i++) {O>Td9  
{ ,?yjsJd.  
nStartPos = input.readLong(); 'f{13-#X@  
nEndPos = input.readLong(); XdJD"|,h  
} sGY}(9ED;  
input.close(); p-"C^=l  
} ) 'xyK  
catch(IOException e){e.printStackTrace ();} .8QhJHwd  
catch(Exception e){e.printStackTrace ();} "#E Z  
} DPf].i#  
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private void processErrorCode(int nErrorCode) _zDS-e@  
{ MX]#|hEeQ  
System.err.println("Error Code : " + nErrorCode); +(DzE H |  
} <9&GOaJ  
drAJ-ii  
"S#$:92  
//停止文件下载 YQD`4ND  
public void siteStop() UhJS=YvT  
{ #fF5O2E'3  
bStop = true; Vb?wwx7=  
for(int i=0;i<nStartPos.length;i++) ^JxVs 7  
fileSplitterFetch.splitterStop(); f=91 Z_M  
%S^ke`MhF  
_8$xsj4_  
} tfHr'Qy BC  
} z2V ->UK)  
//负责部分文件的抓取 kmBA  
**FileSplitterFetch.java `}t5`:#k  
*/ 2.nT k  
package NetFox; hD#Mhy5h  
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.?#Q(eLj  
import java.io.*; yx#!2Z0hw  
import java.net.*; yUcU-pQ  
<>KQ8:  
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public class FileSplitterFetch extends Thread { R1hmJ  
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V9ZM4.,OCN  
String sURL; //File URL %d:cC:`  
long nStartPos; //File Snippet Start Position 6-$95.Y2  
long nEndPos; //File Snippet End Position -^_^ByJe  
int nThreadID; //Thread's ID !*DYdqQ/  
boolean bDownOver = false; //Downing is over
<>5n;-  
boolean bStop = false; //Stop identical iPCn-DoIS  
FileAccessI fileAccessI = null; //File Access interface SIM>Lz  
Bs3&yEq(  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException DQ$m@_/4w  
{ S^1ZsD.  
this.sURL = sURL; \Dr( /n  
this.nStartPos = nStart; pQZ`dS\  
this.nEndPos = nEnd; I<W<;A  
nThreadID = id; K d#(eGe  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 4<<eqxI$|  
} >BJBM |  
yz>S($u  
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public void run() N:KM8PZ&~  
{ |d\1xTBLp  
while(nStartPos < nEndPos && !bStop) 5l,Lp'k  
{ 1D1kjM^Bo  
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try{ N.|zz)y  
URL url = new URL(sURL); s,mt%^
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "Qc4v@~)  
httpConnection.setRequestProperty("User-Agent","NetFox"); :rk6Stn$z  
String sProperty = "bytes="+nStartPos+"-"; CZ^ ,bad  
httpConnection.setRequestProperty("RANGE",sProperty); L;Ynq<x  
Utility.log(sProperty); [@pumH
>  
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^\S~rW.3_  
InputStream input = httpConnection.getInputStream(); /A>nsN?:]  
//logResponseHead(httpConnection); O#!|2qN  
r|z B?9Q  
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byte[] b = new byte[1024]; Wj)v,v2&  
int nRead; %<|<%~l&  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) j:8Pcx  
{ L[5U(`q[  
nStartPos += fileAccessI.write(b,0,nRead); sA+K?_  
//if(nThreadID == 1) =pj3G?F#  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); svt3gkR0  
} p? w^|V  
WS@"
8+re;  
EKuLt*a/  
Utility.log("Thread " + nThreadID + " is over!"); YJDJj x  
bDownOver = true; 4UPxV"H  
//nPos = fileAccessI.write (b,0,nRead); oOLj? 0t  
} <jaQ0S{|  
catch(Exception e){e.printStackTrace ();} #N"QTD|i  
} k5}Qx'/l  
} fC}u
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XKOPW/  
//打印回应的头信息 e?o/H  
public void logResponseHead(HttpURLConnection con) p9MJa[}V  
{ yYTOp^  
for(int i=1;;i++) 1bDXv,nD  
{ s I0:<6W  
String header=con.getHeaderFieldKey(i); QM~~b=P,\  
if(header!=null) I2)2'j,B  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 7?vj+1;  
Utility.log(header+" : "+con.getHeaderField(header)); CLuQ=-[
|  
else `O%
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break; p%#'`*<a_  
} j(>xP*il  
} Vhe$vH  
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_1YC9}  
public void splitterStop() sQ[N3  
{ :/"5x  
bStop = true; niyxZ<Z  
} }YM[aq?6  
\W\*'C8q\  
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} u&o$2 '8  
U+["b-c  

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/* .Ep&O#  
**FileAccess.java Y%}N@ ,lT  
*//文件访问(定位，写) b9v<Jk  
package NetFox; $e uI  
import java.io.*; LEX @hkh  
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public class FileAccessI implements Serializable{ 8L6b:$Y3@C  
{r5OtYmpR  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 AYp~;@  
RandomAccessFile oSavedFile; NnU`u.$D  
long nPos; EP+LK?{%  
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public FileAccessI() throws IOException O,NVhU7,  
{ (I35i!F+tY  
this("",0); MhB>bnWXR  
} B`jq"[w]-  
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L9F71bs59  
public FileAccessI(String sName,long nPos) throws IOException _8\B~;0  
{ nI1(2a1  
oSavedFile = new RandomAccessFile(sName,"rw"); >6)|>#Wi  
this.nPos = nPos; OkCAvRg  
oSavedFile.seek(nPos); }u{gQlV  
} T4[/_;1g  
V\l@_%D[(v  
G!h75G20  
public synchronized int write(byte[] b,int nStart,int nLen) 2Vw2r@S/  
{ QBN\wL8g  
int n = -1; >vO+k^'Y  
try{ M* {5> !\  
oSavedFile.write(b,nStart,nLen); o
/n4M]G  
n = nLen; Ed2A\S6tl  
} 9QL%
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catch(IOException e) %&q}5Y4!  
{ DVJn;X^T:  
e.printStackTrace (); 8B5WbS fL^  
} (XY`1|])`  
ErQ6a%~,  
g#cet{>  
return n; 7q5*grm  
} {t!7r_hj  
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} 9\/oL{  
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l=((>^i  
/* &ODo7@v`1  
**SiteInfoBean.java U%[ye0@:  
*/ VxARJ*4=Y  
package NetFox; ;[(d=6{hc]  
6 .)Xeb"  
$ ]#WC\Hv  
public class SiteInfoBean { GNq f  
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private String sSiteURL; //Site's URL T#*H  
private String sFilePath; //Saved File's Path F*r)  
private String sFileName; //Saved File's Name Im@OAR4,R  
private int nSplitter; //Count of Splited Downloading File gq/Za/!6  
,sL%Ykr  
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public SiteInfoBean() SgehOu  
{//nSplitter的缺省值为5 NY.*
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//default value of nSplitter is 5 bv b\G  
this("","","",5);

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} d!YP{y P  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 5g/,VMe  
{ &}
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sSiteURL= sURL; }(|gC,  
sFilePath = sPath; 5)eM0,:  
sFileName = sName; $?bD55  
this.nSplitter = nSpiltter; r~ 2*'zB  
+>K&zS  
oW6Hufu+o  
} VJ&<6  
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'xGhMgR;  
public String getSSiteURL() !$oa6*<1  
{
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return sSiteURL; /Xb4'Qj  
} VN!
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9Ffam#  
}6/M5zF3  
public void setSSiteURL(String value) XGH:'^o_  
{ h-?yed*?  
sSiteURL = value; MK)}zjw  
} hRu}P"  
=2Yt[8';  
i\ X3t5  
public String getSFilePath() Vb\g49\o/  
{ 4^l9d  
return sFilePath; Pd"c*n&9  
} UNa"\  
cOX)+53  
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public void setSFilePath(String value) T :d+Qz\  
{ ;'8P/a$  
sFilePath = value; uH%b rbrU  
} ?4/pE@RIy  
ZZI} Ot{  

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public String getSFileName() K6p\ >J  
{ z}u`45W+  
return sFileName; !~~KM?g  
}  &kmaKc  
Jj>Rzj!m  
l!88|~  
public void setSFileName(String value) @M4c/k}  
{ ~Dq-q6-@t  
sFileName = value; jsE8=zZs  
} z@~H{glo  
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public int getNSplitter() y,x 2f%x  
{ =f!A o:Uc  
return nSplitter; %"Um8`]FVg  
} e&VC}%m  
l+"p$iZs  
+d\o|}c  
public void setNSplitter(int nCount) )Y)_T&O  
{ |w|c!;,  
nSplitter = nCount; +a.2\Qt2A  
} q<q IT  
} !\R5/-_UU  
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B1 }-   
/* qSr]d`7@  
**Utility.java (x2?{\?  
*/ p]RQ-0  
package NetFox; Gkuqe3

 
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public class Utility { -z`FKej   
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qo3+=*"V  
public Utility() zn
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{ MygAmV&  
Zo&i0%S\E  
1(BLdP3&  
} #G]IEO$M6  
ik(YJw'i7E  
//线程睡眠 ~@c<5 -`{  
public static void sleep(int nSecond) g8MW6Y  
{ i0{\c}r:4b  
try{ hc q&`Gun  
Thread.sleep(nSecond); xS1n,gTA  
} no<$=(11i  
catch(Exception e) d|RUxNjM-J  
{ yk4@@kHW  
e.printStackTrace (); jI\@<6
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} k^%=\c  
} >b2!&dm  
zz U,0 L  
//日志 s;TB(M~i[  
public static void log(String sMsg) B.G6vx4yp  
{ BQPmo1B  
System.err.println(sMsg); Qz|T0\=V  
} c@[Trk m  
$4g
{4-)  
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public static void log(int sMsg) !j'LZ7  
{ LH4#p%Pb%  
System.err.println(sMsg); GLO3v. n;  
} y-+W  
} hb;
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*MmH{!=  
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/* 
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**TestMethod.java C%Lr3M;S'  
*/ As46:<!2  
package NetFox; Y_[7q<L  
yx|iZhK0:}  
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public class TestMethod { ?:$ q~[LY  
:L@;.s  
];w}?LFb  
public TestMethod() sA?8i:]O:  
{ ///xx/weblogic60b2_win.exe "e"#k}z9  
try{ ppz3"5  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [voZ=+/  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); '/xynk%)xw  
SiteFileFetch fileFetch = new SiteFileFetch(bean); EFC+7L(j  
fileFetch.start(); 5?$MZaT  
} Q8`V0E\~  
catch(Exception e){e.printStackTrace ();} 7k*  
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9jImuSZ  
} bX2BEa8<"  
@LOfqQ$FE  
) Z3KO  
public static void main(String[] args) `C: 7N=9  
{ Q*<KX2O  
new TestMethod(); yP3I^>AZ3  
} < +
*  
} i_N8)Z;r  
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