http断点续传简单实现（java)

/* T-cVM>u\D  
**SiteFileFetch.java x=r6vOj  
*/ uRcuy/CY  
package NetFox; .BTT*vL-  
import java.io.*; F"0jr7  
import java.net.*; =,;3z/k%  
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public class SiteFileFetch extends Thread { ',ybHW%D%i  
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SiteInfoBean siteInfoBean = null; //文件信息Bean MZF ;k$R  
long[] nStartPos; //开始位置 \z
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long[] nEndPos; //结束位置 QO^X
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 tKViM@T  
long nFileLength; //文件长度  2x J5  
boolean bFirst = true; //是否第一次取文件 >\Pj(,'  
boolean bStop = false; //停止标志 ]6 7wk  
File tmpFile; //文件下载的临时信息 |,~A9  
DataOutputStream output; //输出到文件的输出流 !7kOw65+0  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） n>+W]I&E  
public SiteFileFetch(SiteInfoBean bean) throws IOException `\uv+^x{  
{ pKlT.<X7  
siteInfoBean = bean; S|h  m  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `^h##WaXap  
if(tmpFile.exists ()) f6C+2L+Hr  
{ Re ur#K  
bFirst = false; bL[W.O0  
read_nPos(); Yx/~8K_%M?  
} +FK<j;}C7  
else  } R6h  
{ *\+'tFT6  
nStartPos = new long[bean.getNSplitter()]; ;lt;]7  
nEndPos = new long[bean.getNSplitter()]; %),O9*[9  
} pjn%CR`;  
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} 74OM tLL$  
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public void run() PKG ,4v=  
{ DKCy h`  
//获得文件长度 VqU:`?#"a  
//分割文件 u^[v{hv'H  
//实例FileSplitterFetch &y?B&4|hM  
//启动FileSplitterFetch线程 Om~C0  
//等待子线程返回 ikiy>W8  
try{ b=l}|)a  
if(bFirst) pQ\ [F  
{ fX|,s2-FW  
nFileLength = getFileSize(); /L Tyiiz6  
if(nFileLength == -1) 6K0*?j{;"  
{ jO.E#Ei}~  
System.err.println("File Length is not known!"); [uHI 6Q#  
} 5q>u }J  
else if(nFileLength == -2) RO8Ynm2 <  
{ U.x.gZRo[  
System.err.println("File is not access!"); I@+<[n2  
} s3^SjZb  
else %>z}P
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{ a{,t@G  
for(int i=0;i<nStartPos.length;i++) @jeV[N,0  
{ *?'T8yf^  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); B9-=.2.WU  
} s[bK
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for(int i=0;i<nEndPos.length-1;i++)  S_6;e|  
{ 2kve?/  
nEndPos = nStartPos[i+1]; \59hW%Di  
} jT0fF  
nEndPos[nEndPos.length-1] = nFileLength; OR{"9)I  
} M XQ7%G  
}
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`,"Jc<R7Z  
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//启动子线程 oPir]`re  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; fok#D>q  
for(int i=0;i<nStartPos.length;i++) K-5)Y+| >  
{ UW3F)  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ma~`&\xE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), "$Q Gifb  
nStartPos,nEndPos,i); H[Cn@XE  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @gz?T;EC  
fileSplitterFetch.start(); VGIc|Q=F  
} 7h~M&\M  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), us+adS.l&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); X}Fv*  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Y$^QH.h  
nEndPos = " + nFileLength); q?\D9aT9  
// fileSplitterFetch[nPos.length-1].start(); \266N;JrN  
w@We,FUJN  
j!dklQh0  
//等待子线程结束 yfrgYA  
//int count = 0; ,\7okf7H,-  
//是否结束while循环 N~(}?'y9S  
boolean breakWhile = false; F\;1:y~1  
tWuQKN`_  
;7hr8?M|  
while(!bStop) ?9"glzxr  
{ KhvCkQMI@  
write_nPos(); x1h!_^(QfF  
Utility.sleep(500); =JkSq J)?  
breakWhile = true; #s%$kYp 1  
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for(int i=0;i<nStartPos.length;i++)
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{ vvCGzOv  
if(!fileSplitterFetch.bDownOver) JAK*HA  
{ " B1' K8  
breakWhile = false; [cq>QMW  
break; b3H;Ea?^^<  
} DS yE   
} $fKWB5p|()  
if(breakWhile) kQ+5pFo3  
break; HZNX1aQ|Q#  
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//count++; ^.Q),{%Xo  
//if(count>4) Aj_}B.  
// siteStop(); dhbJ1/z^  
} CAO$Zt  
% |V:F.f  
6._):[_2  
System.err.println("文件下载结束！"); IkkrnG8  
} E_P]f%  
catch(Exception e){e.printStackTrace ();} jBM>Pe^`3  
} tq[C"| dH  
#@G2n@Hj  
= j -  
//获得文件长度 "q8wEu,z[  
public long getFileSize() [}D)73h`  
{ eYFCf;  
int nFileLength = -1; %?seX+ne  
try{ N~Gh>{N  
URL url = new URL(siteInfoBean.getSSiteURL()); jp|wc,]!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^H'#*b0u  
httpConnection.setRequestProperty("User-Agent","NetFox"); K^+B"  
{ib`mC^  
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int responseCode=httpConnection.getResponseCode(); Wo&i)S<i0F  
if(responseCode>=400) @)}U\=  
{ h!MT5B)r.  
processErrorCode(responseCode); ETtR*5Y 5  
return -2; //-2 represent access is error =S,^"D\Z:  
} |zf||ju  
b\?`721BG  
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String sHeader; $[d}g  
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@  
for(int i=1;;i++) Y:wds=lA  
{ a[/p(O  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); pw,.*N3P  
//Utility.log(in.readLine()); E_? M&  
sHeader=httpConnection.getHeaderFieldKey(i); <]<50  
if(sHeader!=null) m~v Ie c  
{
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if(sHeader.equals("Content-Length")) xnArYm  
{ x/ez=yd*l  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); xucV$[
f  
break; +{s^"M2`  
} aaBBI S  
} S"dQ@r9  
else C9fJLCufC  
break; 3jQ |C=  
} I^o^@C  
} JO$0Z  
catch(IOException e){e.printStackTrace ();} X@ss d  
catch(Exception e){e.printStackTrace ();} Y\rKw!u_!  
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Utility.log(nFileLength); 0Bll6Rd  
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return nFileLength; /w|YNDA]j  
} =<<\Uo  
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//保存下载信息（文件指针位置） zw0p}  
private void write_nPos() ka(xU#;  
{ EV}%D9:  
try{ Xd4~N:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); - na]P3 s  
output.writeInt(nStartPos.length); f~53:;L/  
for(int i=0;i<nStartPos.length;i++) bY`k`3v  
{ }"szL=s  
// output.writeLong(nPos); ,HkJ.6KF  
output.writeLong(fileSplitterFetch.nStartPos); |i|O9^*%  
output.writeLong(fileSplitterFetch.nEndPos); </fzBaTo  
} V3UEuA  
output.close(); n4ISHxM  
} m~}nM|m%  
catch(IOException e){e.printStackTrace ();} f}fM%0/5  
catch(Exception e){e.printStackTrace ();} bv+PbK]iO  
} n9#@ e}r  
;;2s{{(R  
<|{=O9
 
//读取保存的下载信息（文件指针位置） P\Ka'i  
private void read_nPos() Mqna0"IYx*  
{ ]WS 7l@  
try{ {P*RA'H3G  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); u+-}|  
int nCount = input.readInt(); 2nf{2edC  
nStartPos = new long[nCount]; Y,+$vj:y8  
nEndPos = new long[nCount]; CzwnmSv{.  
for(int i=0;i<nStartPos.length;i++) U+\\#5$  
{ uG
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nStartPos = input.readLong(); i6[Hu8  
nEndPos = input.readLong(); Ts.61Rx  
} oRCj]9I$  
input.close(); f>Ge Em~  
} + 505  
catch(IOException e){e.printStackTrace ();} G-Y8<mEh  
catch(Exception e){e.printStackTrace ();} |kjk{  
} Tfj%Sb,zM  
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private void processErrorCode(int nErrorCode) NpSS/rd $  
{ Hi )n]OE  
System.err.println("Error Code : " + nErrorCode); rK"x92P0  
} wz'D4B  
I
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//停止文件下载 tF
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public void siteStop() >1W)J3  
{ -(Yq$5Zc&  
bStop = true; \h:$q E7  
for(int i=0;i<nStartPos.length;i++) UF?qL1w  
fileSplitterFetch.splitterStop(); m'Ran3rp  
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} 59GS:  
} $~_TE\F1  
//负责部分文件的抓取 :X+7}!Wlo  
**FileSplitterFetch.java U1I2+;"#A  
*/ mzDbw-#  
package NetFox; @<h@d_8^k  
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tX)^$3A  
import java.io.*; }s? 9Hnqa  
import java.net.*; c!b4Y4eJ  
.|!Kv+yD  
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public class FileSplitterFetch extends Thread { Zhf+u r  
4v Ug:'DM  
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String sURL; //File URL u1rT:\G1  
long nStartPos; //File Snippet Start Position y4+Km*am,W  
long nEndPos; //File Snippet End Position $vx]\` ^  
int nThreadID; //Thread's ID L~>pSP^a  
boolean bDownOver = false; //Downing is over d7A vx  
boolean bStop = false; //Stop identical (V#5Cs,o:  
FileAccessI fileAccessI = null; //File Access interface ym^  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException }
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{ 6VW&An[6r  
this.sURL = sURL; +hGr2%*0f  
this.nStartPos = nStart; IvO#tI  
this.nEndPos = nEnd; Tw8$6KUW  
nThreadID = id; M/T ll]\|  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 BVU>M*k  
} q9|'!m5K  
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public void run() mSr(PIH{\  
{ s>ilxLSX]  
while(nStartPos < nEndPos && !bStop) n2cb,b/7  
{ '_>8_  
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try{ w6aq/m"'  
URL url = new URL(sURL); G?*)0`~W  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); FbhF45H  
httpConnection.setRequestProperty("User-Agent","NetFox"); <<4U:  
String sProperty = "bytes="+nStartPos+"-"; yJNQO'wcv  
httpConnection.setRequestProperty("RANGE",sProperty); $cflF@3  
Utility.log(sProperty); @#rF8;  
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InputStream input = httpConnection.getInputStream(); P9c!  
//logResponseHead(httpConnection); 2M@,g8O+B=  
~qT5F)$B-  
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byte[] b = new byte[1024]; Dn~c  
int nRead; yH/m@#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) _TEjB:9eY  
{ R.^ Y'TLyc  
nStartPos += fileAccessI.write(b,0,nRead); dg-nv]7  
//if(nThreadID == 1) b@`h]]~:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Bq@_/*'*Y  
} bi~1d"j  
}hRw{#*8  
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Utility.log("Thread " + nThreadID + " is over!"); [_PZdIN  
bDownOver = true; O%}?DiSl  
//nPos = fileAccessI.write (b,0,nRead); LD/NMb  
} lub_2Cb|j  
catch(Exception e){e.printStackTrace ();} Q #IlUo  
} ip8%9fG\>  
} fRh}n ^X  
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{
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//打印回应的头信息 |kGj}v3  
public void logResponseHead(HttpURLConnection con) z[|2od  
{ iC2``[m"  
for(int i=1;;i++) /0CS2mLC  
{ *!NxtB!LC  
String header=con.getHeaderFieldKey(i); ?sD4S   
if(header!=null) OGcq]u
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); 5v5)vv.kd  
Utility.log(header+" : "+con.getHeaderField(header)); p4-UW;Xu  
else n37P$0  
break; Q?xA))0  
} [3D*DyQt  
} v9*31Jx  
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public void splitterStop() w#}[=jy  
{ 'Y2ImSWj  
bStop = true; z;wOtKl5r  
} N2 4J!L  
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} k~Z;S QyN  
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uo9FLm  
/* {;5\#VFg  
**FileAccess.java Ahkq  
*//文件访问(定位，写) Y]VLouzl  
package NetFox; @B\$ me  
import java.io.*; ZSvU1T8  
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L9{y1'')  
public class FileAccessI implements Serializable{ o4U0kiI@  
CFXr=.yz  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 B@k2lHks(  
RandomAccessFile oSavedFile; 56o(gCj?y  
long nPos; Q2qT[aD,  
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public FileAccessI() throws IOException P](/5KrK  
{ .no<#l
 
this("",0); ULH<FDot  
} @)XR  
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public FileAccessI(String sName,long nPos) throws IOException U3u j`Oq  
{ (}m2}  
oSavedFile = new RandomAccessFile(sName,"rw"); (&MtK1;
;  
this.nPos = nPos; %/oeV;D  
oSavedFile.seek(nPos); (
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} nT :n>ja  
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X'{o/U.  
public synchronized int write(byte[] b,int nStart,int nLen) smKp3_r  
{ TXT!Ae  
int n = -1; _9yW; i-  
try{ 2q4-9vu  
oSavedFile.write(b,nStart,nLen); >N~orSw%  
n = nLen; s~06%QEG  
} `{%ImXQF  
catch(IOException e) &G!~@\tMg  
{ #(}'G*  
e.printStackTrace ();  oP~%7Jt  
} 5[LDG/{Tys  
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return n; ";jKTk7  
} n"w>Y)C(X)  
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} cHC1l  
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/* 
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**SiteInfoBean.java )>tT""yEl  
*/ %/2OP &1<  
package NetFox; l?A~^4(5a/  
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public class SiteInfoBean { &o]fBdn  
cJ\1ndBH  
,zEPdhTX  
private String sSiteURL; //Site's URL T_[5 ZYy  
private String sFilePath; //Saved File's Path [Lcy &+  
private String sFileName; //Saved File's Name VIaj])m  
private int nSplitter; //Count of Splited Downloading File dDA,Ps  
fu iTy72  
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public SiteInfoBean() t>P[Yld"  
{//nSplitter的缺省值为5 WMS~Bk+!  
//default value of nSplitter is 5 %GP`H/H(  
this("","","",5); !?" pnKb}  
} [e>2HIS,  
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L|8&9F\  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) %%9T-+T  
{ p7W9?b9  
sSiteURL= sURL; 0ybMI+*  
sFilePath = sPath; BoXPX2:  
sFileName = sName; =zR9^k  
this.nSplitter = nSpiltter; Yyw9IYB;  
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ydMhb367|  
} f\FqZ?w  
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{113B)  
public String getSSiteURL() `_sKR,LhB  
{ XqGa]/;}  
return sSiteURL; cSjX/%*!m  
} xt6%[)  
3L-$+j~u  
g'Wr+(A_  
public void setSSiteURL(String value) Z5g*'  
{ U] P{~
 
sSiteURL = value; <kJ`qbOU  
} |9Y~
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public String getSFilePath() 9VMk?   
{ &;RBG$t  
return sFilePath; pd|l&xvka  
} - _~\d+>w  
_C=01 %/  
_88X-~.  
public void setSFilePath(String value) WHqw=!G  
{ ps^["3e  
sFilePath = value; |n;5D,r0C  
} C)~%(< D  
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,&g-DCag  
public String getSFileName() `4e| I.`^r  
{ t>Yl=79,  
return sFileName; ix38|G9U  
} ol~ tfS  
~i.rk#{?D  
:QF`Orb!^  
public void setSFileName(String value) Zq'FOzs  
{ 0d$LUQ't  
sFileName = value; zcuz @  
} s`pdy
$  
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public int getNSplitter() ]z2x`P^oI  
{ F$'po#  
return nSplitter; KO/#
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} ^)o]hE|  
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public void setNSplitter(int nCount) [ {HTGz@(  
{ ;Aheeq746  
nSplitter = nCount; og_ylCh:  
} BjHp3-A'  
} nGsFt.  
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8w#4T:hsuN  
/* >p`i6_P0P/  
**Utility.java RjR+'<7E^  
*/ E>:#{%  
package NetFox; 'e6J&X  
xTqP`ljX  
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public class Utility { cEn|
Q  
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]AZCf`7/?  
public Utility() ~jzT;9:  
{ p@h<u!rL8  
7\X_%SM%  
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} s){VU2.ra  
'H"!%y{:i  
//线程睡眠 U lCw{:#F  
public static void sleep(int nSecond) Nr}O6IJ>Sg  
{ xZ* B}O{{H  
try{ b2RW
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Thread.sleep(nSecond); 9!0-~,o  
} vP_mS 4X  
catch(Exception e) ^W`RBrJay  
{ x_
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e.printStackTrace (); 3JD"* <zs  
} 9yu#G7  
} 'j?
H>'t{  
Hn/V*RzQ  
//日志 zm_8{Rta}  
public static void log(String sMsg) ZkdSgc')  
{ >.H}(!  
System.err.println(sMsg); ^)'D eP/  
} 4F<was/  
ScQ9p379  
uz:r'+v  
public static void log(int sMsg) |h&okR+
_,  
{ JUJrtKS  
System.err.println(sMsg); di]CYLf  
} b(adM3MP  
} L-m' #  
k4en/&  
n\$.6 _@x  
/* L+mHeS l  
**TestMethod.java #KuBEHr  
*/ H`yUSB IP  
package NetFox; T hVq5  
&V%faa1  
sp_19u  
public class TestMethod { 2_Zn?#G8dl  
z~i>GN_  
.4Mc4'  
public TestMethod() +(`.pa z@  
{ ///xx/weblogic60b2_win.exe %WqUZ+yy  
try{ vrh2}biCR  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); U.=TjCW  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); i3)7Qa[  
SiteFileFetch fileFetch = new SiteFileFetch(bean); |Qpd<L  
fileFetch.start(); g6$\i m  
} Moi>Dp  
catch(Exception e){e.printStackTrace ();} hVCxwTg^X  
e?\hz\^  
mZ0_^  
} 8M]QDgd.  
}0>\%C  
vq\L9$WJ  
public static void main(String[] args) ,,g: x  
{ m!(dk]  
new TestMethod(); &#9HV  
} )Ofwfypc  
} .$+,Y4q~(  
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