http断点续传简单实现（java)

/* "0CjP+1k  
**SiteFileFetch.java #]E(N~  
*/ @*>Sw>oet  
package NetFox; Y ya`&V  
import java.io.*;
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import java.net.*; cK@jmGj+  
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public class SiteFileFetch extends Thread { krB'9r<wa`  
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SiteInfoBean siteInfoBean = null; //文件信息Bean -F\qnsZ2  
long[] nStartPos; //开始位置 ;apzAF  
long[] nEndPos; //结束位置 2-'Opu  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 $s\UL}Gc  
long nFileLength; //文件长度 ;@3FF  
boolean bFirst = true; //是否第一次取文件 e5?PkFV^a1  
boolean bStop = false; //停止标志 a.@qGsIH  
File tmpFile; //文件下载的临时信息 ~Rpm-^  
DataOutputStream output; //输出到文件的输出流 T6#CK  
`.%JjsD<  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） !ABiy6d  
public SiteFileFetch(SiteInfoBean bean) throws IOException rJJ[X4$  
{ vUA0FoOp  
siteInfoBean = bean; cXnKCzSxZq  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); -|S]oJy  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); G8Z4J7^  
if(tmpFile.exists ()) i3VW1~.8  
{ S'LZk9E  
bFirst = false; *\uM.m0$
 
read_nPos(); K_/zuTy  
} DgHaOAdU  
else 3;[DJ5  
{ b:J(b?  
nStartPos = new long[bean.getNSplitter()]; MZ>6o5K|  
nEndPos = new long[bean.getNSplitter()]; p(F" /  
} /9pM>Cd*Z  
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} S4^N^lQ]  
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public void run() ZR0r>@M3v<  
{ Iu@y(wyg  
//获得文件长度 -r7]S  
//分割文件 Z8#Gwyinx  
//实例FileSplitterFetch S8d8%R~1=h  
//启动FileSplitterFetch线程 5kypMHJm  
//等待子线程返回 ~EzaC?fQ  
try{ :1ecx$  
if(bFirst) !y:%0{l  
{ cO2& VC  
nFileLength = getFileSize(); ~PWSo%W8  
if(nFileLength == -1) U69u'G:  
{ fBn"kr;  
System.err.println("File Length is not known!"); 4Y> Yi*n  
} (-77[+2  
else if(nFileLength == -2) Ny- [9S-<  
{ YevyN\,}V!  
System.err.println("File is not access!"); M:KbD|  
} g7V8D  
else l_'[27
 
{ )d\j I  
for(int i=0;i<nStartPos.length;i++) (>4aibA'P  
{ :~Q!SL N  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); }R[#?ty;]  
} $?G"GQ!.  
for(int i=0;i<nEndPos.length-1;i++) g
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{ m([(:.X/IX  
nEndPos = nStartPos[i+1]; oX@ya3!Pz  
} )tHaB,  
nEndPos[nEndPos.length-1] = nFileLength; LVJI_O{fH  
} 7hW+T7u?  
} ._w8J"E5  
=L|tp%!  
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//启动子线程 w%AcG~`j!B  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; /M;#_+VK<  
for(int i=0;i<nStartPos.length;i++) aI(7nJ=R  
{ NcOPL\  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o%{'UG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), )n49lr6X  
nStartPos,nEndPos,i); :A %^^F%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5!YA o\S  
fileSplitterFetch.start(); %J:SO_6  
} gWABY%!}  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =gfI!w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?"#%SKm  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", QxuhGA  
nEndPos = " + nFileLength); p.I.iAk%G^  
// fileSplitterFetch[nPos.length-1].start(); 7(M(7}EKA  
w=]Ks'C]  
%W,D;?lEo>  
//等待子线程结束 X"gCRn%tn  
//int count = 0; pLa[}=  
//是否结束while循环 '{I_\~*  
boolean breakWhile = false; =deMd`=J  
fDE%R={!n5  
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while(!bStop) CQ`=V2:"ON  
{ _=ua6}Xp  
write_nPos(); ^;,M}|<h  
Utility.sleep(500); a?|vQ*W  
breakWhile = true; *<N3_tx"  
>3 yk#U|7}  
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for(int i=0;i<nStartPos.length;i++) ~DRmON5 M  
{ F' U 50usV  
if(!fileSplitterFetch.bDownOver) |@,|F:h<M  
{ NK|?
y  
breakWhile = false; /525w^'pd  
break; f/WQ[\<!I  
} iGB_{F~t4}  
} T=hhoGn  
if(breakWhile) v_e9}yI  
break; J"=1/,AS  
} VJfJ/  
J q{7R  
//count++; xtPLR/Z  
//if(count>4) L9pvG(R%  
// siteStop(); lis/`B\x  
} WN(ymcdYB  
h)~=Dm  
 Qk!;M|
 
System.err.println("文件下载结束！");  +`7KSwa  
}
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catch(Exception e){e.printStackTrace ();} N#lDW~e'  
} 'r(1N
j  
-a*K$rnB  
DD" $1o"  
//获得文件长度 1/p*tZP8i  
public long getFileSize() {G <kA(Lm  
{ syU9O&<  
int nFileLength = -1; y/e2l  
try{ dz~coZ9  
URL url = new URL(siteInfoBean.getSSiteURL()); vR0];{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bjAnaya  
httpConnection.setRequestProperty("User-Agent","NetFox"); ThPE 0V  
>!_Xgw  
< >UPD02  
int responseCode=httpConnection.getResponseCode();  h:lt<y  
if(responseCode>=400) ]Jh+'RK\#  
{ y_xnai  
processErrorCode(responseCode); aP'"G^F  
return -2; //-2 represent access is error ARcv;H 5  
} 8|E'>+ D_-  
JS}{%(B  
XLMb=T~S  
String sHeader; s1|/S\
  
q+B&orp  
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for(int i=1;;i++) ==i[w|  
{ XqM3<~$  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); cYXM__  
//Utility.log(in.readLine()); /1?R?N2>0  
sHeader=httpConnection.getHeaderFieldKey(i); @HZKc\1  
if(sHeader!=null) cRX~z  
{ >0p$(>N]  
if(sHeader.equals("Content-Length")) }j,[ 1@S  
{ L[5=h  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); d #jK=:eK  
break; Z|RY2P>E  
} Xf)|Pu  
} 099sN"kf  
else -,K!  
break; q80S[au  
} ]*7Y~dO  
} EUsI%p  
catch(IOException e){e.printStackTrace ();} oK{ V7  
catch(Exception e){e.printStackTrace ();} UT}i0I9  
1-RIN}CSd  
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Utility.log(nFileLength); EGl^!.'  
"UwH\T4I  
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return nFileLength; 1s1=rZ!  
} 5U_H>oD  
<0S=,!  
5>AX*]c  
//保存下载信息（文件指针位置） T{wuj[Q#:  
private void write_nPos() u&wiGwF[  
{ j5@:a  
try{ K'#E3={tt  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 
+
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output.writeInt(nStartPos.length); =IAsH85Q  
for(int i=0;i<nStartPos.length;i++) \QU^>23  
{ Xl74@wq   
// output.writeLong(nPos); Ts~L:3oaQ  
output.writeLong(fileSplitterFetch.nStartPos); $ cj>2.  
output.writeLong(fileSplitterFetch.nEndPos); `K,1K  
} G\NPV
'  
output.close(); 
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} ^&g=u5 d0  
catch(IOException e){e.printStackTrace ();} wcDRH)AW.  
catch(Exception e){e.printStackTrace ();} !bV5Sr^  
} ]({~,8s  
43V}#DA@  
VY)s+Bx  
//读取保存的下载信息（文件指针位置） q\\gpCgp  
private void read_nPos() v
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{ /  g 2b  
try{ IHRGw  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); kA7mLrON  
int nCount = input.readInt(); IKie1!ZU{"  
nStartPos = new long[nCount]; cyJG8f  
nEndPos = new long[nCount]; bTQNb!&  
for(int i=0;i<nStartPos.length;i++) Ytg
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{ aZbw]0q@o  
nStartPos = input.readLong(); l3 DYg  
nEndPos = input.readLong(); 1#1 riM -  
} u+{a8=  
input.close(); /PsnD_s]5  
} }jill+]  
catch(IOException e){e.printStackTrace ();} A=Ss6-Je  
catch(Exception e){e.printStackTrace ();} %c[V  
} #pcP!  
:T9<der,  
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private void processErrorCode(int nErrorCode) Pb*5eXk  
{ GKcv<G208  
System.err.println("Error Code : " + nErrorCode); a'\o7_  
} Mfv1Os:ST  
t|m=J`a{q;  
q{+_ <2U|  
//停止文件下载 10H)^p%3+  
public void siteStop() <oz!H[!  
{ zRPeNdX  
bStop = true; vB+ '  
for(int i=0;i<nStartPos.length;i++) Zdn~`Q{  
fileSplitterFetch.splitterStop(); "1,pHR-+R  
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;qBu4'C)T  
} T9s2bC.z55  
} @gG<le6  
//负责部分文件的抓取 \rPbK+G.  
**FileSplitterFetch.java O(_[ayE  
*/ &5:tn=E  
package NetFox; B-l'
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import java.io.*; B2ec@]uD`  
import java.net.*; 36am-G  
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public class FileSplitterFetch extends Thread { h>Hb`G<  
-1J[n0O.  
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String sURL; //File URL )Y)pmjZaG  
long nStartPos; //File Snippet Start Position xpOg8u5  
long nEndPos; //File Snippet End Position  }K3x  
int nThreadID; //Thread's ID >a}f{\Q  
boolean bDownOver = false; //Downing is over @/k@WhFZ  
boolean bStop = false; //Stop identical Onwp-!!.  
FileAccessI fileAccessI = null; //File Access interface @Pt="*g  
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~}<DG1!  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException H9CS*|q6r  
{ B,{K*-7)MX  
this.sURL = sURL; MR}Agu#LG  
this.nStartPos = nStart; +a*tO@HG  
this.nEndPos = nEnd; \G-KplKS  
nThreadID = id; &~W:xg(jN  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9*a=iL*Nw  
} h9eMcCU  
5ls6t{Ci  
-{ZWo:,r~q  
public void run() 0tU.(  
{ 4^URX>nx8  
while(nStartPos < nEndPos && !bStop) QVtQx>K`  
{ a1@Y3MQ;i  
%HJK;   
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try{ <n#DT  
URL url = new URL(sURL); *BR^U$,e  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1/"WD?a  
httpConnection.setRequestProperty("User-Agent","NetFox"); rdJR 2  
String sProperty = "bytes="+nStartPos+"-"; s-v  
httpConnection.setRequestProperty("RANGE",sProperty); &?(?vDFfZ  
Utility.log(sProperty); +>PX&F  
6:~v4W!k  
)P+7PhE{J  
InputStream input = httpConnection.getInputStream();
!50[z:  
//logResponseHead(httpConnection); & \f{E\A#  
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,{mCf^  
byte[] b = new byte[1024]; ?Ec7" hK  
int nRead; f`Fi#EKT  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) zE_i*c"`  
{ D gaMO,  
nStartPos += fileAccessI.write(b,0,nRead); YD7Oao4:o  
//if(nThreadID == 1) $ , u+4h  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); X*\J_  
} #{\%rWnCm  
JeE;V![  
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Utility.log("Thread " + nThreadID + " is over!"); E@b(1@  
bDownOver = true; )KAEt.  
//nPos = fileAccessI.write (b,0,nRead); rh^mJUh  
} r3PT1'P?L  
catch(Exception e){e.printStackTrace ();} cMOyo<F#^=  
} LSRk7'0  
} o !U 6?  
}B1!gz$YNO  
,l)^Ft`5  
//打印回应的头信息 1
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public void logResponseHead(HttpURLConnection con) .;N1N^  
{ (UxW;  
for(int i=1;;i++) _FWBUZ;N  
{ U-3i  
String header=con.getHeaderFieldKey(i); w.TuoWo>  
if(header!=null) =z /dcC$r  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); @!1x7%]G  
Utility.log(header+" : "+con.getHeaderField(header)); BSVx
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else c3CWRi`LE  
break; wY_)y  
} _/tHD]um  
} 9c("x%nLpB  
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~ (jKz}'~U  
public void splitterStop() T]c%!&^_  
{ lx7Q.su
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bStop = true; &:`U&06q  
} (P:<t6;+  
#n8IZ3+
  
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} Ug<#
en  
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/* q1KZ5G)6GJ  
**FileAccess.java \}|o1Xh2  
*//文件访问(定位，写) Sxh]R+Xb  
package NetFox; Iepsz  
import java.io.*; jJPGrkr  
4.5|2\[  
#*UN
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public class FileAccessI implements Serializable{ $[a8$VY^Cm  
0a XPPnuX  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]Yn_}Bq  
RandomAccessFile oSavedFile; SR|`!  
long nPos; @/ohg0  
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public FileAccessI() throws IOException 9eQxit7  
{ R1$:~p2m  
this("",0);   t!_<~  
} ElW~48  
1^}[&ar  
b?lD(fa&  
public FileAccessI(String sName,long nPos) throws IOException =h5H~G5AT  
{ ]z/8KL  
oSavedFile = new RandomAccessFile(sName,"rw"); oV|4V:G q  
this.nPos = nPos; \6Zr  
oSavedFile.seek(nPos); [rV>57`YD  
} 4p,EBn9(  
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GE%Z9#E  
public synchronized int write(byte[] b,int nStart,int nLen) P 'od`  
{ hFy;ffs.  
int n = -1; DrY:9[LP  
try{ ]Hefm?9*^  
oSavedFile.write(b,nStart,nLen); j~jV'f.:H  
n = nLen; =*c7i]@}  
} .7avpOfz  
catch(IOException e) #PH~1`vl  
{ IS&ZqE(`e  
e.printStackTrace (); NUWDc]@J*  
} =k^Y?.  

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return n; a C\MJ9  
} OX?\<),  
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} m!tbkZHQn0  
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/* LcTt)rs f  
**SiteInfoBean.java O @j} K4  
*/ ':3pq2{  
package NetFox; {YAJBIvHV  
jN;@

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public class SiteInfoBean { q=Sgk>NA  
%Q fO8P  
e]$}-i@#  
private String sSiteURL; //Site's URL 1Vrh4g.l  
private String sFilePath; //Saved File's Path QLvHQtzwX  
private String sFileName; //Saved File's Name J$GUB3 G  
private int nSplitter; //Count of Splited Downloading File 1VG4S){}\9  
ZQ%'`q\c  
 ~-_kM  
public SiteInfoBean() 2a`o &S  
{//nSplitter的缺省值为5 L\xk:j1[  
//default value of nSplitter is 5 Ez fN&8E  
this("","","",5); KyYMfC  
} gM u"2I5  
t!W(_8j  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)
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{ KWowN;  
sSiteURL= sURL; e478U$  
sFilePath = sPath; >>t@}F)  
sFileName = sName; Eg#K.5hJ  
this.nSplitter = nSpiltter; ~obqG!2m  
"$+Jnc!!  
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} |Mup8(gCk  
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public String getSSiteURL() 4ew" %Cs*  
{ bYpntV  
return sSiteURL; t^R][Ay&  
} bnq;)>&  
2Mc3|T4)U  
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public void setSSiteURL(String value) ~J wb`g.  
{ RKHyw08  
sSiteURL = value; &5fJPv &  
} c'>/  
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{\  
public String getSFilePath() XHK<AO^  
{ 4sF"6+%5d  
return sFilePath; 5cL83FQh  
} 1 d}Z(My  
u~7hWiY<2  
H]{v;;'~  
public void setSFilePath(String value) C*)3e*T
*  
{ GP!?^r:en  
sFilePath = value; |[<_GQl  
} U@_dm/;0&  
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, pDnRRJ!  
public String getSFileName() 5[k/s}g  
{ Xx."$l  
return sFileName; :DrWq{4  
} `w#Oih!6A|  
[R(`W#W  
Y!~49<;  
public void setSFileName(String value) $+8cc\fq  
{ Pk{_(ybaY  
sFileName = value; bv]`!g: C  
} LSa,1{  
p4.wh|n  
X@+{5%  
public int getNSplitter() n7B7m,@1  
{ $2oTkOA   
return nSplitter; "bF
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} u)X=Qm)  
r?
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public void setNSplitter(int nCount) >Ea8G,  
{ ~
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nSplitter = nCount; :~b3^xhc^  
} p `8s  
} 0bceI  
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/* 1n >X[! 8x  
**Utility.java AF;)#T<  
*/ rn/ /%  
package NetFox; 3m]4=  
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public class Utility { 5gH1.7i b  
,X[ktz  
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public Utility() 2#KJ asX  
{ "cE7 5  
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} q-[@$9AS  
.
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//线程睡眠 f/ ?_  
public static void sleep(int nSecond) 9_q#W'/X  
{ |4)>:d  
try{ HmiR.e%<b  
Thread.sleep(nSecond); ^1S!F-H4\  
} PlU*X8  
catch(Exception e) ?J%1#1L"/  
{ B-?6M6#  
e.printStackTrace (); yCd-9zb=  
} L"E7#}  
} <;9I@VYK  
0Iw
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//日志 ?Nup1!D  
public static void log(String sMsg) 2KB\1&N  
{ !*s?B L  
System.err.println(sMsg); iqC|G/  
} RY]#<9>M  
`>7;!  
chcbd y>C  
public static void log(int sMsg) PXK7b2fE.  
{ 6_J$UBT
 
System.err.println(sMsg); ^Ew]uN>,  
} 8UXjm_B^'  
} oiF}?:7Q7  
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lW+\j3?Z$  
/* ;+e}aER&9  
**TestMethod.java O!mvJD  
*/ 8>trS=;n  
package NetFox; (n*^4@"2
 
#^`4DhQ/ 1  
<>dT64R|  
public class TestMethod { -|J"s$yO4  
m4TE5q%3
 
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public TestMethod() NO~*T?&  
{ ///xx/weblogic60b2_win.exe T_i:}ul  
try{ $*SW8'],`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); HTVuStM8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); *i\Qo  
SiteFileFetch fileFetch = new SiteFileFetch(bean); D N'3QQn  
fileFetch.start(); ?^H `M|S  
} _g+JA3sIJ  
catch(Exception e){e.printStackTrace ();} Vu)4dD!  
|*oZ_gI  
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} q+Lr"&'Q  
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public static void main(String[] args) SFB~ ->db  
{ ^"VJd[Hn  
new TestMethod(); W}3.E "K  
} "8c@sHk(w  
} 1%EBd%`#  
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