http断点续传简单实现（java)

/* ;O1jf4y  
**SiteFileFetch.java A@Q6}ESD  
*/ >yr;Y4y7K  
package NetFox; :2H]DDg(  
import java.io.*; K\wu9z8M  
import java.net.*; T;5VNRgpI  
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public class SiteFileFetch extends Thread { yUWc8]9\W  
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SiteInfoBean siteInfoBean = null; //文件信息Bean KTt+}-vP^  
long[] nStartPos; //开始位置 !zt
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long[] nEndPos; //结束位置 `-%dHvB^R  
FileSplitterFetch[] fileSplitterFetch; //子线程对象  Cu5_OJ  
long nFileLength; //文件长度 cpl Ny?UIC  
boolean bFirst = true; //是否第一次取文件 Ux1j+}y  
boolean bStop = false; //停止标志 '$Z@oCY#  
File tmpFile; //文件下载的临时信息 [) 0JI6  
DataOutputStream output; //输出到文件的输出流 VH4wsEH]  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ZJW8S  
public SiteFileFetch(SiteInfoBean bean) throws IOException uB^"A ;0v  
{ %19~9Tw  
siteInfoBean = bean;  pdm(7^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,}\LC;31,  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); n-2!<`UFX  
if(tmpFile.exists ()) tH&eKM4
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{ [<5/s$,i  
bFirst = false; yZ7)|j  
read_nPos(); b1>]?.  
} 
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else A9N8Hav  
{ oexTz[  
nStartPos = new long[bean.getNSplitter()]; R(pQu! K4  
nEndPos = new long[bean.getNSplitter()]; P>u2""c  
} fPHV]8Ft|  
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} ,"5HJA4  
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public void run() T59FRX  
{ ]KEE+o  
//获得文件长度 Q|P M6ta  
//分割文件 4W|cIcU W  
//实例FileSplitterFetch @{#'y4\>  
//启动FileSplitterFetch线程 P=1Ku|k  
//等待子线程返回 WY QVe_<z:  
try{ iDX<`)  
if(bFirst) 50|nQ:u,  
{ (tq);m&  
nFileLength = getFileSize(); \a7m!v  
if(nFileLength == -1) IJKdVb~   
{ c~/poFj  
System.err.println("File Length is not known!"); n$N
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} S"@6,  
else if(nFileLength == -2) 3 ^x&G?)  
{ :CezkD&  
System.err.println("File is not access!"); QHja4/
 
} WF*j^ %5  
else xjF>AAM_Px  
{ ~:k r;n2  
for(int i=0;i<nStartPos.length;i++) )7!,_r  
{ %QrOEs  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ^!C  
} 4YI6&  
for(int i=0;i<nEndPos.length-1;i++) c%O97J.5b  
{ }"nm3\Df  
nEndPos = nStartPos[i+1]; )MSCyPp5  
} A$7K5  
nEndPos[nEndPos.length-1] = nFileLength; J"< h#@`  
} k"%JyO8Y
 
} Nt]nwae>A  
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//启动子线程 Ct?xTFb  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; [O'aka Q  
for(int i=0;i<nStartPos.length;i++) Y@k=m )zE  
{ _-H,S)kI`  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Vt \g9-[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ?Fl O,|   
nStartPos,nEndPos,i); 9{geU9&Z  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nh0gT>a>@  
fileSplitterFetch.start(); <+r~?X_  
} p5OoDo  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `Ix`/k}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !5h-$;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 'AWWdz  
nEndPos = " + nFileLength); i;/;zG^=_  
// fileSplitterFetch[nPos.length-1].start(); 9=6BQ`u  
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//等待子线程结束 t'J4zV  
//int count = 0; ,SIGfd  
//是否结束while循环 |:4W5>sfg  
boolean breakWhile = false; (pM&eow}  
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while(!bStop) -DJ,<f*$  
{ z79oj\&[  
write_nPos(); x!W5'DO  
Utility.sleep(500); /&G|.Cx  
breakWhile = true; ltU{P|7!E  
+:jv )4^O  
6Y6t.j0vN.  
for(int i=0;i<nStartPos.length;i++) Y1>OhHuN  
{ RTbV!I  
if(!fileSplitterFetch.bDownOver) _*g
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{ Z8/
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breakWhile = false; ^V9|uHOJoq  
break; AB0}6g^O  
} ~.J*_0~Ze  
} -R1;(n)  
if(breakWhile) gaNe\  
break; _,v?rFLE  
B 5qy4MFWs  
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//count++; pRxVsOb  
//if(count>4) FIAmAZH}_  
// siteStop(); Isvb;VT9L  
} pbqk  
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4JXvP1`  
System.err.println("文件下载结束！"); w'_|X&@H  
} fWWB]h  
catch(Exception e){e.printStackTrace ();} m+7%]$  
}
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!
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K
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//获得文件长度 {*g{9`   
public long getFileSize() P_mP ^L  
{ `-cw[@uD  
int nFileLength = -1; bQ 0Ab"+D  
try{ sUR5Q/Q  
URL url = new URL(siteInfoBean.getSSiteURL()); FqGMHM\J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )MTf  
httpConnection.setRequestProperty("User-Agent","NetFox"); yP}
|8x  
_ MB
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int responseCode=httpConnection.getResponseCode(); 50A\Y)i_mZ  
if(responseCode>=400) 0wSy[z4V  
{ f-H"|9  
processErrorCode(responseCode); v@2@9/  
return -2; //-2 represent access is error %qE"A6j  
} @}waZ?'  
+>2.O2)%q  
  </5  
String sHeader; wL]#]DiE  
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2?:OsA}  
for(int i=1;;i++) (d,OLng  
{ 8yDsl  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^r(]S%  
//Utility.log(in.readLine()); 8KkN "4'  
sHeader=httpConnection.getHeaderFieldKey(i); PA*k|  
if(sHeader!=null) ?UIW&*h}  
{ Z5P4 H  
if(sHeader.equals("Content-Length")) l=Jw6F+5  
{ pV\>?  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); N7}3?wS  
break; 7B5b +  
} PBEi"`i  
} -bSM]86  
else Pf?&ys6  
break; CK|AXz+EN  
} ^5?|Dj  
} #cW:04  
catch(IOException e){e.printStackTrace ();} xX{Zh;M&[  
catch(Exception e){e.printStackTrace ();} ]mNsG0r6  
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m!^$_d\%~  
Utility.log(nFileLength); Uugq.'>  
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return nFileLength; aMkuyqPf{  
} ySDo(EI4  
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//保存下载信息（文件指针位置） Rg46V-"d,@  
private void write_nPos() (JjxrZ+L  
{ #D?w,<_8,  
try{ tu{paQ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); aTvLQ@MQ  
output.writeInt(nStartPos.length); P\{s C6E  
for(int i=0;i<nStartPos.length;i++) ^'Rs`e  
{ 9jx>&MnWs  
// output.writeLong(nPos); 9&C8c\Y  
output.writeLong(fileSplitterFetch.nStartPos); z?kE((Ey  
output.writeLong(fileSplitterFetch.nEndPos); ]:T:cO0_n  
} y@2"[fo3~  
output.close(); KyP@ hhj  
} ''!j:49  
catch(IOException e){e.printStackTrace ();} q@VIFmqY!  
catch(Exception e){e.printStackTrace ();} nox-)e  
} saQo]6#  
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//读取保存的下载信息（文件指针位置） )$a6l8  
private void read_nPos() EKN<KnU%  
{ K&gE4;>  
try{ $83Qd  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,VUOsNN4\  
int nCount = input.readInt(); KIWHn_ :  
nStartPos = new long[nCount]; -*ZQ=nomN  
nEndPos = new long[nCount]; xdaq` ^Bbt  
for(int i=0;i<nStartPos.length;i++) d|~'#:y@  
{ @;{ZnRv14  
nStartPos = input.readLong(); x{So  
nEndPos = input.readLong(); '0_W<lGB  
} $rbr&TJ  
input.close(); T?jN/}qg  
} tO1k2<Z"Y&  
catch(IOException e){e.printStackTrace ();} 4 CiRh  
catch(Exception e){e.printStackTrace ();} Hv:~)h$  
} ^u0y<kItX  
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private void processErrorCode(int nErrorCode) Yb[)ETf^  
{ pa?AKj]  
System.err.println("Error Code : " + nErrorCode); rTJqw@]#WH  
} H+gB|  
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3KkJQ5a  
//停止文件下载 3|)cT1ej  
public void siteStop() \S?-[v*{  
{ fT?m~W^  
bStop = true; 6e5A8e8"]  
for(int i=0;i<nStartPos.length;i++) w_~tY*IwB  
fileSplitterFetch.splitterStop(); =1)9>=}  
asy:[r"  
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} 1E4`&?  
} GN5*  
//负责部分文件的抓取 %=s2>vv9  
**FileSplitterFetch.java E6T=lwOZ  
*/ 2pSp(@N3  
package NetFox; VtU2&  
M-+!z5q~d  
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import java.io.*; C+t
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import java.net.*; Z3u6m0!  
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public class FileSplitterFetch extends Thread { Y[rCF=ZVH  
od,,2pwK+  
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String sURL; //File URL ,LL
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long nStartPos; //File Snippet Start Position &Akw V-  
long nEndPos; //File Snippet End Position =W"T=p*j  
int nThreadID; //Thread's ID !kh:zTP  
boolean bDownOver = false; //Downing is over <9$Pl%:  
boolean bStop = false; //Stop identical qzZ;{>_f  
FileAccessI fileAccessI = null; //File Access interface oGbh*  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <@4V G
 
{ ).Iifu|
ks  
this.sURL = sURL; >*+n`"6  
this.nStartPos = nStart; ~Xr[d07bC  
this.nEndPos = nEnd; pMAFZfte!x  
nThreadID = id; >,)U46  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *lheF>^  
} NNJQDkO-I  
+OSSgY$  
j!0-3YKv  
public void run() x%W~@_  
{ mr]~(]B?r  
while(nStartPos < nEndPos && !bStop) l6MBnvi  
{ a%an={  
5~#oQ&  
!# xi^I  
try{ u,`V%J?vW  
URL url = new URL(sURL); Aaz:C5dtU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D&],.N  
httpConnection.setRequestProperty("User-Agent","NetFox"); c% ?@3d  
String sProperty = "bytes="+nStartPos+"-"; P/k#([:2  
httpConnection.setRequestProperty("RANGE",sProperty); G \$x.  
Utility.log(sProperty); =4!m]*y  
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4JH^R^O<n  
InputStream input = httpConnection.getInputStream(); U:PtRSdn!b  
//logResponseHead(httpConnection); e%9zY{ABR%  
l Yj$3  
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byte[] b = new byte[1024]; 2@N-#x'  
int nRead; Dj0D.}`~  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) oXVx9dZ  
{ QV#HN"F/K  
nStartPos += fileAccessI.write(b,0,nRead); uFvR(LDb&g  
//if(nThreadID == 1) 3?!c<^"e  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]&='E.f  
} e_S,N0  
jF#Dc[*  
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Utility.log("Thread " + nThreadID + " is over!"); eG
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bDownOver = true; "412w^5[T  
//nPos = fileAccessI.write (b,0,nRead); Tg=P*HY6  
}  Tx'anP  
catch(Exception e){e.printStackTrace ();} x69RQ+Vw  
} l @E {K|
 
} fP\*5|7%R  
-BwZ  
,~Lx7 5{  
//打印回应的头信息 (H]NL  
public void logResponseHead(HttpURLConnection con) DW)81*~g  
{ 9R[PpE''  
for(int i=1;;i++) f]Rh<N$  
{ >LVGNicQ  
String header=con.getHeaderFieldKey(i); 3A! |M5  
if(header!=null) xxC2 h
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); p@@*F+  
Utility.log(header+" : "+con.getHeaderField(header)); <?Z]h]C^o  
else I&% Z*H  
break; =&: |a$C  
} uj)f
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} idjk uB(6  
v++&%  
{~'Iu8TvZ  
public void splitterStop() O`9vEovjs  
{ 1V,DcolRY  
bStop = true; Jgq#m~M6  
} 1T4#+kW&  
b |ijkys  
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} *qr>x8OGp  
*c(YlfeZ#  
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/* E$v!Z;A  
**FileAccess.java r#J_;P{U  
*//文件访问(定位，写) pMf ?'l  
package NetFox; ]#'&x%m  
import java.io.*; 5'|W
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~L_1&q^4!i  
public class FileAccessI implements Serializable{ $h >rs  
~bw=;xF{3  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 wF*9%K'E  
RandomAccessFile oSavedFile; "9NWsy}<c  
long nPos; K}Q:L(SSr\  
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{_Fh3gjb/  
public FileAccessI() throws IOException Ia[<;":U  
{ mPo.Z"uy7  
this("",0); gzDfx&.0  
} 1q|iw  
?YF2Uc8z%2  
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public FileAccessI(String sName,long nPos) throws IOException E!=Iz5
 
{ Ns\};j?TU*  
oSavedFile = new RandomAccessFile(sName,"rw"); (543`dqAmC  
this.nPos = nPos; 0~Xt_rN](  
oSavedFile.seek(nPos); 1c*;Lr.K  
} u Vo"_c w  

Q&w"!N  
l.BiE<&  
public synchronized int write(byte[] b,int nStart,int nLen) c^z)[  
{ qu;$I'Ul%  
int n = -1; C4 -y%W"P  
try{ `yC[Fn"E^  
oSavedFile.write(b,nStart,nLen); HNLr} Yj  
n = nLen; Dnd  
} MieO1l  
catch(IOException e) x-b}S1@  
{ @yF>=5z:  
e.printStackTrace (); blkPsp)m"  
} bicbCC6kC  
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/RWD\u<l  
return n; 4rpry@1  
} Fv:x>qZr@  
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} b&RsxW7  
9!ARr@ ;  
O.{
  
/* 6lUC$B Y  
**SiteInfoBean.java 7/)0{B4U'  
*/ =JxEM7r  
package NetFox; t~":'le`zr  
8=g~+<A  
p ^9o*k`u  
public class SiteInfoBean { ZWKvz3W
t  
(&X/n=UI  
KWM}VZY:Z  
private String sSiteURL; //Site's URL Af}o/g  
private String sFilePath; //Saved File's Path |<uBJ-5  
private String sFileName; //Saved File's Name g@Rs.Zq  
private int nSplitter; //Count of Splited Downloading File 7JBr{3;eS  
v<mSd2B*  
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public SiteInfoBean() 4E+8kz'  
{//nSplitter的缺省值为5 C 1)+^{7ef  
//default value of nSplitter is 5 2#s8Dxt  
this("","","",5); $UpWlYwG  
} 5tEkQ(Ei8  
 SWyJ`  
n$E$@  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 3Zwhv+CP[  
{ _9?v?mL5;  
sSiteURL= sURL; 5f2=`C0_  
sFilePath = sPath; }'Ph^ %ox  
sFileName = sName; x{/-&`F  
this.nSplitter = nSpiltter; /)<kG(Z  
.kJu17!  
>;%LW} %  
} J|VDZ# c7  
Y' 5X4Ks|  
ja(ZJ[<`  
public String getSSiteURL() Y=y 0`?K  
{ QP>F *A  
return sSiteURL; 8~g~XUl  
} Rm~8n;7oOr  
?8;WP&  
<;cch6Z  
public void setSSiteURL(String value) fUZCP*7>  
{ D}UgC\u  
sSiteURL = value; 1K'cT\aFm  
} "~Zdv}^xS  
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public String getSFilePath() uO1^nK  
{ ZP-9KA$"  
return sFilePath; ]cWQ9  
} D%6
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H}(WL+7  
public void setSFilePath(String value) r
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{ '2rSX[$tf  
sFilePath = value; u`Kc\BSn  
} ft0tRv(s:  
12Fnv/[n'K  
7uOtdH+  
public String getSFileName() fJe5 i6`(  
{ ^ (J%)&_\3  
return sFileName; T7l,}G  
} p4kK" \ln  
7Q,<h8N\5  
u#Bj#y!  
public void setSFileName(String value) ]I]G3 e  
{ CZ%KC$l.5  
sFileName = value; uLNOhgSUf  
} 4w]<1V  
gADqIPu]  
fgHsg@33N  
public int getNSplitter() Cv p#=x0  
{ #Yy5@A}`o  
return nSplitter; 3_T'0x\FP  
} u=E &jL5U  
Ec}9R3 m  
, 10+Sh  
public void setNSplitter(int nCount) iTF%}(  
{ yA7O<p+  
nSplitter = nCount; \Rha7O  
} llCE}Vdh  
} (&, E}{p9  
x}x)h3e  
)*7{%Ilq  
/* 4`7~~:W!M5  
**Utility.java $XKUw"%  
*/ `V.tqZF  
package NetFox; ?DnQU"_$  
~
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public class Utility { >:0N)Pj  
auM1k]  
7 Rc/<,X  
public Utility() ?q0a^c?A^  
{ uwt29  
M
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ZvK3Su)f1  
} @(."[O:  
TT){15T;"  
//线程睡眠 qR , 5  
public static void sleep(int nSecond) dkg+_V!  
{ @9
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try{ h,K&R8S  
Thread.sleep(nSecond); pTJ_DH  
} ?wjk=h
M2  
catch(Exception e) +LF=oM<  
{ PI8ag  
e.printStackTrace (); h-o;
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} e"Z,!Q^-L  
} CM`Q((  
+.$:ZzH#  
//日志 2Ns<lh   
public static void log(String sMsg) $0]5b{i]  
{ 9N|JI3*41  
System.err.println(sMsg); Eh"Y<]$  
} ?pA_/wwp  
e`5:46k|  
=Hj3o_g-  
public static void log(int sMsg) -ilhC Y@M  
{ vJW`aN1<I3  
System.err.println(sMsg); h}S2b@e|  
} 4&6cDig7*2  
} P)ne^_   
-'i[/{  
h[C XH"  
/* 5Iv"  
**TestMethod.java ]0{,P !  
*/
=E~_F>SD  
package NetFox; *6v5JH&K  
cc"<H}g>`  
\`8F.oZ^)  
public class TestMethod { {4%ddJn[.)  
E>"SC\#7  
"`w*-O  
public TestMethod() viVn  
{ ///xx/weblogic60b2_win.exe = @FT$GQ  
try{ u4[JDB7t
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Fo]]j=  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); bnE&-N*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); LI"N^K'z  
fileFetch.start(); /4+*!X  
} YT@H^=  
catch(Exception e){e.printStackTrace ();} va.Ve# N  
)P.,h&h/  
[c99m:*+  
} sr:hRQ27  
rj<-sfs  
>waA\C}  
public static void main(String[] args) _G)x\K]N  
{ -1R7 8(1  
new TestMethod(); 2%]#rZ  
} `Cu9y+t  
} .;D'  
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