http断点续传简单实现（java)

/* r'/7kF- 5  
**SiteFileFetch.java YCwf
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*/ 3F ;+D  
package NetFox; mnM#NT5]  
import java.io.*; uhUC m  
import java.net.*; oB:tio4DE  
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public class SiteFileFetch extends Thread { J7BfH,o  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 0+b1R}!2  
long[] nStartPos; //开始位置 C8%Iol  
long[] nEndPos; //结束位置 83UIH0(  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 d-g&TSGd  
long nFileLength; //文件长度 2H8,&lY.p  
boolean bFirst = true; //是否第一次取文件 xX`P-h>V`c  
boolean bStop = false; //停止标志 (eI'%1kS<  
File tmpFile; //文件下载的临时信息 |q5R5m
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DataOutputStream output; //输出到文件的输出流 h_4o4#  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ZYoWz(  
public SiteFileFetch(SiteInfoBean bean) throws IOException  q&0Jl  
{ -A>1L@N  
siteInfoBean = bean; [ZS}P  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); le%_[/_I|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); *p{wC r  
if(tmpFile.exists ()) 8Letpygm  
{ WRQJ6B  
bFirst = false; Vd[[<  
read_nPos(); r{.DRbn  
} Wa%Zt*7  
else m/sAYF"  
{ <4,>`#NEo  
nStartPos = new long[bean.getNSplitter()]; NrVrR80Y  
nEndPos = new long[bean.getNSplitter()]; &Ib8xwb:  
} yzt6  
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} A/Kw"l>  
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public void run() JK.lL]<p i  
{ Q*mzfsgr  
//获得文件长度 ;JMd(\+-  
//分割文件 j"*ZS'0  
//实例FileSplitterFetch mXT{)pU  
//启动FileSplitterFetch线程 G<,@|6"w  
//等待子线程返回 f_X]2in  
try{ r'M|mQ$s>  
if(bFirst) FMB\$(g  
{ oop''6`C%  
nFileLength = getFileSize(); IC>OxYg*  
if(nFileLength == -1) k.>*!l0  
{ `6`NuZ*6g  
System.err.println("File Length is not known!"); ~?8B
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} Q@hx+aM  
else if(nFileLength == -2) #P$=P2o  
{ a9qB8/Gg[  
System.err.println("File is not access!"); "BZ6G`  
} RG-pN()  
else w1EYXe  
{ S P)$K=  
for(int i=0;i<nStartPos.length;i++) =1f
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{ g<O*4 ]=  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); -Y
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} {XiBRs e  
for(int i=0;i<nEndPos.length-1;i++) ncf=S(G+  
{ g4_DEBh  
nEndPos = nStartPos[i+1]; $A)i}M;uK  
} y% =n
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nEndPos[nEndPos.length-1] = nFileLength; f m.-*`ax  
} o0^'xVv  
} 7. 9n  
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//启动子线程 FqAW><  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; nk9Kq\2f:  
for(int i=0;i<nStartPos.length;i++) s2L|J[Y"s  
{ 8;/`uB:zV  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7$'%*|C.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Iw
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nStartPos,nEndPos,i); S',i  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kxp$Nnk  
fileSplitterFetch.start(); 'CsD[<  
} Q3,`'[ F  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _@jBz"aq\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); O79;tA<k
 
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", F@4XORO;  
nEndPos = " + nFileLength); KB!.N[!v  
// fileSplitterFetch[nPos.length-1].start(); $/5<f<%u&)  
fg"@qE-;  
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//等待子线程结束 #+p30?r0y  
//int count = 0; a
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//是否结束while循环 f~-81ctu  
boolean breakWhile = false; 3Vjuk7  
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-~ytk=  
while(!bStop) 3/mVdU?U  
{ )nU%}Z  
write_nPos(); Gjq:-kX\  
Utility.sleep(500); eYBo*  
breakWhile = true; >HO{gaRM  
1$oVcDLl  
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for(int i=0;i<nStartPos.length;i++) j$<uE{c  
{ L8n1p5gx3  
if(!fileSplitterFetch.bDownOver) pvM;2  
{ zlzr;7m  
breakWhile = false; H S/1z  
break;  c'?4*O  
} AEaT  
} }7YDe'5V  
if(breakWhile) B MU@J  
break; Dv?'(.z  
o.U$\9MNP  
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//count++; (v(!l=3  
//if(count>4) CL%?K<um  
// siteStop(); Gs%IZo_  
} z5IHcZ  
> ^fY`x,  
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System.err.println("文件下载结束！"); u38FY@U$  
} .QOQqU*2I  
catch(Exception e){e.printStackTrace ();} x'*,~u  
} 3`_jNPV1  
qCK)FOU  
>ijFQ667>j  
//获得文件长度 opTDW)  
public long getFileSize() Z0T{1YEJ  
{ Et~b^8$>  
int nFileLength = -1; :gv`)  
try{ b2c% 0C  
URL url = new URL(siteInfoBean.getSSiteURL()); jq(3y|6,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7onMKMktM%  
httpConnection.setRequestProperty("User-Agent","NetFox"); = aSHb[hO  
[Z6]$$!#2  
*9)7.}uY  
int responseCode=httpConnection.getResponseCode(); )
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if(responseCode>=400) |`T3H5X>  
{ K;;Q*NN-  
processErrorCode(responseCode); Im%|9g;P  
return -2; //-2 represent access is error pv039~Sud  
} _ b}\h,Ky  
8=ubMqr[  
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String sHeader; v
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for(int i=1;;i++) s`Fv!  
{ lM Gz"cym  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); J411bIxD+q  
//Utility.log(in.readLine()); o+{}O_r  
sHeader=httpConnection.getHeaderFieldKey(i); 3=~"<f l  
if(sHeader!=null) -H~g+i*J  
{ >R3~P~@30  
if(sHeader.equals("Content-Length")) _H^Ij  
{ 6~GaFmW=  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ;>[).fX>/  
break; g6EdCG.V  
}
xG0IA 7  
} f ^mxj/%L  
else YXXUYi~!f  
break; Z:aDKAboU  
} nMc3.fM  
} Mh'QD)28c  
catch(IOException e){e.printStackTrace ();} I2("p.+R  
catch(Exception e){e.printStackTrace ();} T:x5 ,vpM  
>1:s.[&  
@8C^[fDL  
Utility.log(nFileLength); At%g^  
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return nFileLength; kbBD+*  
} ^ cN-   
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//保存下载信息（文件指针位置） ` _()R`=  
private void write_nPos() q:#,b0|bv  
{ -_'M *-  
try{ *{tn/ro6a  
output = new DataOutputStream(new FileOutputStream(tmpFile)); R
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output.writeInt(nStartPos.length); VuFMjY  
for(int i=0;i<nStartPos.length;i++) Mo &I
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{ DU$]e1  
// output.writeLong(nPos); \*6%o0c  
output.writeLong(fileSplitterFetch.nStartPos); :Oo  
output.writeLong(fileSplitterFetch.nEndPos); "-XL Y_  
} |tz1'YOB  
output.close(); },0fPkVsU  
} ]g3&gw  
catch(IOException e){e.printStackTrace ();} {>OuxVl??k  
catch(Exception e){e.printStackTrace ();} 7M}T^LC  
} (rFY8oHD  
U jVo "K  
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//读取保存的下载信息（文件指针位置） qfE/,L(B  
private void read_nPos() f[ GH  
{ MUz.-YRt  
try{ {.SN  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !Qrlb>1z-  
int nCount = input.readInt(); Svn|vH  
nStartPos = new long[nCount]; J/w?F
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nEndPos = new long[nCount]; 2j-|.l c  
for(int i=0;i<nStartPos.length;i++) n?@3R#4D3  
{
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nStartPos = input.readLong(); 2tCep  
nEndPos = input.readLong(); g]iWD;61  
} /fA:Fnv  
input.close(); 8gJ"7,}-'  
} /MsXw/],  
catch(IOException e){e.printStackTrace ();} ~^" cNv  
catch(Exception e){e.printStackTrace ();} ;E:ra_l  
} ?v#t{e0eQ  
.Xo, BEjE/  
n5 @H  
private void processErrorCode(int nErrorCode) s\#kqw\x  
{ Zi$a6  
System.err.println("Error Code : " + nErrorCode); *Au4q<  
} ;M8N%  
vuuID24:  
Ts:dnGR5  
//停止文件下载 Z4}Yw{=f  
public void siteStop() Y[$[0  
{ RmO-".$yt  
bStop = true; |^Try2@  
for(int i=0;i<nStartPos.length;i++) tbAN{pX  
fileSplitterFetch.splitterStop(); go6Hb>  

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} x*i5g`jx  
} =w".B[r  
//负责部分文件的抓取 ~Ht[kO  
**FileSplitterFetch.java 8l>/ZZ.NXi  
*/ LGK0V!W  
package NetFox; [[JwHM8H&  
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import java.io.*; T'\lntN  
import java.net.*; #$K\:V+ 4  
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public class FileSplitterFetch extends Thread { it
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String sURL; //File URL vrGRZa  
long nStartPos; //File Snippet Start Position g[-'0d\1  
long nEndPos; //File Snippet End Position M=26@ n  
int nThreadID; //Thread's ID ,":ADO-  
boolean bDownOver = false; //Downing is over eXnMS!g%Z  
boolean bStop = false; //Stop identical 7 -gt V#  
FileAccessI fileAccessI = null; //File Access interface -[`,MZf  
)Y Qtrc\91  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException $>OWGueq64  
{ :
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this.sURL = sURL; HkJ$r<J2  
this.nStartPos = nStart; SR%h=`t  
this.nEndPos = nEnd; }UHuFff,  
nThreadID = id; 76} N/C  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 0mH>fs 4  
} oO$a4|&,  
q<r{ps  
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public void run() nW{). P  
{ h<6@&yzp  
while(nStartPos < nEndPos && !bStop) ?t'O\n)M  
{ j9) Z'L  
^=pn!lK;^  
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try{ `t{aN|3V[  
URL url = new URL(sURL); +MGEO+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +aEE(u6%E@  
httpConnection.setRequestProperty("User-Agent","NetFox"); pUYa1=  
String sProperty = "bytes="+nStartPos+"-"; q,^^c
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httpConnection.setRequestProperty("RANGE",sProperty); E>
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Utility.log(sProperty); f`RcfYt  
Uj0DX>I  
9FX'Uws  
InputStream input = httpConnection.getInputStream(); 4ZQXYwfC|  
//logResponseHead(httpConnection); /tJJ2 =%l  
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#J, `a.  
byte[] b = new byte[1024]; JdfjOlEb  
int nRead; 87>\wUJ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) E{_p&FF  
{ G7M:LcX  
nStartPos += fileAccessI.write(b,0,nRead); Hl?\P6  
//if(nThreadID == 1) _E:]qv  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .AWRe1?  
} v\c.xtjI5x  
r_-iOxt~5  
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Utility.log("Thread " + nThreadID + " is over!"); ,l#V eC  
bDownOver = true; c+_F nA  
//nPos = fileAccessI.write (b,0,nRead); i=o<\{iV:  
} hoO8s#0ED  
catch(Exception e){e.printStackTrace ();} Tr(w~et  
} * "~^k^_b}  
} 31 QT  
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//打印回应的头信息 F[l{pc "C  
public void logResponseHead(HttpURLConnection con) 71@V|$Dy  
{ +smPR  
for(int i=1;;i++) ^$6EO)<  
{ )C<c{mjk(  
String header=con.getHeaderFieldKey(i); qI) Yzc/  
if(header!=null) T,!?+#  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); JyjS#BWi  
Utility.log(header+" : "+con.getHeaderField(header)); S$=])^dur  
else 7-'!XD!  
break; b9%hzD,MR  
} A>bo Xcr  
} UCa(3p^V_  
3!Gnc0%c  
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public void splitterStop() mPi4.p)  
{ ES(b#BlrP/  
bStop = true; bs kG!w  
} -nV]%vJ$R}  
:&/'rMi<T  
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} (m|p|rL  
"/(J*)%{  
|/
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/* (VI4kRj  
**FileAccess.java *A@~!@XE4  
*//文件访问(定位，写) }{n[_:[7  
package NetFox; <JuP+\JAm  
import java.io.*; ,l_"%xYx  
nkG1&wiX  
\{\*h/m  
public class FileAccessI implements Serializable{ MIsjTKE  
q#xoM1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 'Wn'BRXq3  
RandomAccessFile oSavedFile; \@N8[  
long nPos; Y#=0C*FS  
\uc]+nV!o  
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public FileAccessI() throws IOException ^r?ZrbS
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{ }Cvf[
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this("",0); 7ykpDl^@  
} Z_zN:BJ8L  
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public FileAccessI(String sName,long nPos) throws IOException A%-*M 'J  
{ z|Q)^  
oSavedFile = new RandomAccessFile(sName,"rw"); }G]6Rip3  
this.nPos = nPos; #e}Q|pF  
oSavedFile.seek(nPos); $>hPB[[  
} 4[44Eku\  
Kyq/'9`  
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public synchronized int write(byte[] b,int nStart,int nLen) /vYuwaWG=  
{ l:-$ulAx  
int n = -1; 3,8<5)ds*  
try{ ]]Sz|6P  
oSavedFile.write(b,nStart,nLen); j_H9l,V  
n = nLen; )>QpR8 G-  
} ^RAst1q7  
catch(IOException e) <'>c`80@\*  
{ v,I4ozDx  
e.printStackTrace (); ve49m%NQ  
} zVKbM3(^  
_D1Uc|  
7?9QlUO  
return n; >gRb.-{ux  
} zR_ "  
s!:'3[7+  
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} i882r=TE3  
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/* Za_w@o  
**SiteInfoBean.java _ I"}3*  
*/ v*iD)k:|t  
package NetFox; K|%.mcs4  
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public class SiteInfoBean { &b'IYoe  
Lp.dF)C\  
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private String sSiteURL; //Site's URL w<#/ngI2  
private String sFilePath; //Saved File's Path <'N"GLJ  
private String sFileName; //Saved File's Name ^SM>bJ1Z_  
private int nSplitter; //Count of Splited Downloading File f^Sl(^f  
~Ap.#VIc'  
\5M1;  
public SiteInfoBean() Q=9Ce@[  
{//nSplitter的缺省值为5 fUx;_GX?  
//default value of nSplitter is 5
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this("","","",5); U2<8U  
} `v?XFwnV`  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]s_,;PGU  
{ iga.B  
sSiteURL= sURL; ~ES6Qw`Oe  
sFilePath = sPath; yw
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sFileName = sName; S9RH&/^H  
this.nSplitter = nSpiltter; yhm
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} =\~<##sRJ  
u#!Q
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tf[)Q:|  
public String getSSiteURL() a;bmZh  
{ ZDny=&>#  
return sSiteURL; K93L-K^J  
} %4'<0  
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;$,b w5  
public void setSSiteURL(String value) n=Ze p{^  
{ JOwm|%>3a  
sSiteURL = value; D[/h7Ha  
} X'FDQoH  
,/2&HZd  
9`y@2/!Y  
public String getSFilePath() M`V<`  
{ Z<D8{&AjS  
return sFilePath; Xna58KF/  
} g$f+X~Q  
R*0]*\C z  
7<GC{/^T  
public void setSFilePath(String value) | KtI:n4d  
{ IVSOSl|  
sFilePath = value; C(CwsdlP  
} UOIB}ut V  
56w uk [)  
W{A4*{  
public String getSFileName() J4?i\wD:  
{ Mh"X9-Ot  
return sFileName; 6mV-+CnYC  
} w1Txz4JqB  
qXqGhHoe;  
2ieyU5q7#  
public void setSFileName(String value) @cB7tY*Ski  
{ w.VjGPp  
sFileName = value; "hid3"G  
} AjVX  
e dTFk$0  
a\-AGG{2/X  
public int getNSplitter() :A7\eN5  
{ dJv2tVm&'  
return nSplitter; ?}RPnf  
} %lq[,6?>5  
9Js+*,t  
w)N~u%  
public void setNSplitter(int nCount) 9U>OeTh(  
{ )Cu2xRr^`  
nSplitter = nCount; y%Rq6P=4Q  
} Ie4\d2tQ;  
} wKU9I[]  
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/* p0rmcP1Ln  
**Utility.java  LXoZ.3S  
*/ mq}V @H5  
package NetFox; n g%~mt  

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@AtJO>w  
public class Utility { (^oN, 7  
`=V p 0tPI  
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public Utility() 7Q^p|;~a  
{ brCXimG&jo  
'Zs3b4n8  
{oSdVRI  
} p$=Z0p4%LL  
KFgq3snH  
//线程睡眠 $J8g)cS  
public static void sleep(int nSecond) / 3eGt7x#  
{ f$76p!pDa  
try{ W_L*S4 ~  
Thread.sleep(nSecond); w_h{6Kc<  
} cgnMoBIc  
catch(Exception e) dbJ3E)rF  
{ Q.?(h! )9  
e.printStackTrace (); "1$
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} 0qINa:Ori  
} EXMW,  
!9.k%B:  
//日志 QJ&]4*>a  
public static void log(String sMsg) STl8h}C  
{ -Ew>3Q  
System.err.println(sMsg); E
.%V0}  
} b(oe^jeGz  
N5c*#lHI  
jG~
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public static void log(int sMsg) :i4AkBNK  
{ 0K'{w]Q  
System.err.println(sMsg); 5vFM0  
}  zo1T`"Y  
} inY_cn?  
0W0GSDx  
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/* ;>uB$8<_7  
**TestMethod.java B}S+/V` Y5  
*/ r?itd)WC<X  
package NetFox; =+
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 svx7  
public class TestMethod { AR!v%Z49i  
NE.h/+4  
v%$l(  
public TestMethod() OK)>QGl  
{ ///xx/weblogic60b2_win.exe wz1nV}  
try{ -oUGmV_  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); @0]w!q  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 0C;Js\>3]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8 :WN@  
fileFetch.start(); w$IUm_~waa  
} 4#{f8  
catch(Exception e){e.printStackTrace ();} 
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^KdT,
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} (/2rj[F&  
t{>#)5Pqv  
\6
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public static void main(String[] args) )!kt9lK  
{ tA^+RO4  
new TestMethod(); T$`m!mQ4  
} S{?l/*Il*_  
} aGBd~y@e  
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