http断点续传简单实现（java)

/* )a`kL,  
**SiteFileFetch.java 6BEDk!  
*/ MIWc @.i2  
package NetFox; k5+ Fxf  
import java.io.*; t'.:"H8BI  
import java.net.*; }9;mtMR$  
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public class SiteFileFetch extends Thread { :QXKG8^  
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SiteInfoBean siteInfoBean = null; //文件信息Bean W%o! m,zFM  
long[] nStartPos; //开始位置 A0v@L6m-O  
long[] nEndPos; //结束位置 ];N/KHeZ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 PpF`0w=1%l  
long nFileLength; //文件长度 |)*!&\Ch  
boolean bFirst = true; //是否第一次取文件 hFhC&2HN  
boolean bStop = false; //停止标志 [kqO6U  
File tmpFile; //文件下载的临时信息 <i`s)L  
DataOutputStream output; //输出到文件的输出流 X;#Ni}af  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ~d ~oC$=TC  
public SiteFileFetch(SiteInfoBean bean) throws IOException B7oUS}M  
{ 2=1qmQE  
siteInfoBean = bean; kqq1;K
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); s
;]"LD@  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); gi)C5J4  
if(tmpFile.exists ()) :7(d6gEL  
{ 7|
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bFirst = false; w"O;: `|n  
read_nPos(); |tTcJ\bG  
} &4l!2  
else [MKt\(  
{ 3Ljj|5.q
  
nStartPos = new long[bean.getNSplitter()]; Lc "{eP
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nEndPos = new long[bean.getNSplitter()]; wgq=9\+&  
} ejbtdU8N<  
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} -_]Ceq/  
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public void run() |W&K@g$  
{ EZhk(LE  
//获得文件长度 mGoC8t}iP  
//分割文件
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//实例FileSplitterFetch P4c}@Mq3  
//启动FileSplitterFetch线程 !FB2\hiM  
//等待子线程返回 1CV?  
try{ 9[`\ZGWD  
if(bFirst) f2v~
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{ N4{g[[ T  
nFileLength = getFileSize(); v3kT~uv  
if(nFileLength == -1) m2ph8KC  
{ O(_f&a  
System.err.println("File Length is not known!"); fWF!%|L  
} s!Iinc^p  
else if(nFileLength == -2) (/t{z=  
{ vy>(?[  
System.err.println("File is not access!"); h96<9L  
} r]wy-GT  
else y S<&d#:"  
{ q 1u_r  
for(int i=0;i<nStartPos.length;i++) >N}+O<Fc  
{ <xH! Yskc  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); s9fEx-!y  
} C/ ]Bx  
for(int i=0;i<nEndPos.length-1;i++) ;$qc@)Uwp  
{ AU9:Gu@M/  
nEndPos = nStartPos[i+1];
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} H$ :BJ$x@  
nEndPos[nEndPos.length-1] = nFileLength; (dV7N  
} *)HVK&'  
} F`+S(APT8  
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//启动子线程 !9j6l0  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; l SuNZYaO  
for(int i=0;i<nStartPos.length;i++) DLe>EU;vS  
{ th0>u.hJ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >km$zfM2-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), pNu?DF{ 3  
nStartPos,nEndPos,i); ,I,Zl.5  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [g+WL\1  
fileSplitterFetch.start(); G,(Xz"`,  
} i"E_nN"V  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); xZloEfv.B  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", b8$%=Xp  
nEndPos = " + nFileLength); C?6q]k]r  
// fileSplitterFetch[nPos.length-1].start(); -:b<~S[  
2t=&h|6EW  
2{g&9  
//等待子线程结束 {WeRFiQ?-  
//int count = 0; jX t5.9 t  
//是否结束while循环 \oP  
boolean breakWhile = false; i9peQ61{  
+hlR  
4(,X.GVY/  
while(!bStop) >F/E,U ]  
{ hWX4 P  
write_nPos(); gDX\ p>7  
Utility.sleep(500); .l,NmF9  
breakWhile = true; *_ajb:  
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^{E_fQJX  
for(int i=0;i<nStartPos.length;i++) f uH3C~u7<  
{ nGTqW/k[+s  
if(!fileSplitterFetch.bDownOver) Fg2/rC:_  
{ cn9=wm\\  
breakWhile = false; E6-~  
break; &G3$q,`H  
} }UG<_bE|  
} (YYwn@NGj  
if(breakWhile) W)Yo-%  
break; V<KjKa+sG  
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<  
//count++; ^[2siG  
//if(count>4) ]Rmu+N|  
// siteStop(); :/}=s5aQl/  
} =knBwjeD  
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System.err.println("文件下载结束！"); :"+3Uk2  
} *kJa$3*r  
catch(Exception e){e.printStackTrace ();} |Y(  
} ,%y!F3m  
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//获得文件长度 2k`Q+[?{q>  
public long getFileSize() ~k ]$J|}za  
{ 8,B#W#*{  
int nFileLength = -1; G/KTF2wl7  
try{ X8XE_VtP  
URL url = new URL(siteInfoBean.getSSiteURL()); 2nSz0 .  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @,pn/[  
httpConnection.setRequestProperty("User-Agent","NetFox"); H\|H]:CE  
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int responseCode=httpConnection.getResponseCode(); }</"~Kw!  
if(responseCode>=400) !zfV(&  
{ j<L!(6B  
processErrorCode(responseCode); O%Qz6R  
return -2; //-2 represent access is error sWP_fb1  
} |j$$0N  
8: VRq  
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String sHeader; N,ZmGzNP)  
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for(int i=1;;i++) u>2opI
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{ pq
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); m2F+6G  
//Utility.log(in.readLine()); 2o0WS~}5  
sHeader=httpConnection.getHeaderFieldKey(i); SFqq(K2u  
if(sHeader!=null) 9['>$ON  
{ 70nBC  
if(sHeader.equals("Content-Length")) 2j[;M-3  
{ 2(Nf$?U@0  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); cvV8;  
break; d ?,wEfwp  
} <!?ZH"F0  
} ,u.A[{@py  
else !\q'{x5C  
break; Acb %)Y  
} ;]%Syrzp  
} 4uv*F:eo  
catch(IOException e){e.printStackTrace ();} 74KR.ABd  
catch(Exception e){e.printStackTrace ();} Dh9C9<Ta:  
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Utility.log(nFileLength); KhyGz"I!@$  
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return nFileLength; #| m*
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} #-g2p?+i&  
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8oP"?ew#  
//保存下载信息（文件指针位置） MAgoxq~;V  
private void write_nPos() -qB{TA-.\  
{ W)u9VbPk[  
try{ }DkdF  
output = new DataOutputStream(new FileOutputStream(tmpFile)); fvoPV&:  
output.writeInt(nStartPos.length); WAGU|t#."  
for(int i=0;i<nStartPos.length;i++) ET~^P  
{ q&: t$tSS  
// output.writeLong(nPos); q>VvXUyK,  
output.writeLong(fileSplitterFetch.nStartPos); 3O?[Yhk`.  
output.writeLong(fileSplitterFetch.nEndPos); 51!#m|  
} <+ckE2j  
output.close(); 5Ja[p~^
L  
} G2FD'Sf  
catch(IOException e){e.printStackTrace ();} 2L7ogyrU/A  
catch(Exception e){e.printStackTrace ();} -qDL':  
} W_|7hwr  
k FE<M6a9@  
J-~:W~Qx4N  
//读取保存的下载信息（文件指针位置） h.aXW]]}(P  
private void read_nPos() r59BBW)M  
{ g|x*sZR~Y  
try{ #lx(F3  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Pb/[945  
int nCount = input.readInt(); PkDh[i9Z|  
nStartPos = new long[nCount]; |`@7G`x  
nEndPos = new long[nCount]; lD?]D&  
for(int i=0;i<nStartPos.length;i++) UphZRgT!N  
{ ":01M},RA  
nStartPos = input.readLong(); Yr 1k\q  
nEndPos = input.readLong();
?4lEHef  
} bU_P@GKB  
input.close(); S| l%JM^  
} :n$?wp  
catch(IOException e){e.printStackTrace ();} $Q56~AP  
catch(Exception e){e.printStackTrace ();} %Yny/O\e%  
} UAtdRVi]M  
r-c1_ [Q#  
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private void processErrorCode(int nErrorCode) Zex`n:Wl?j  
{ Uy{ZK*c8i  
System.err.println("Error Code : " + nErrorCode); jGOE CKP  
} 4Kn)5>  
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)<^G]a
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//停止文件下载 gqACIXR  
public void siteStop() 3qwSm<  
{ _S6SCSFc  
bStop = true; L7$1rO<  
for(int i=0;i<nStartPos.length;i++) 2<^eVpNJR  
fileSplitterFetch.splitterStop(); cK1RmL"3  
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} r$;u4FR  
} MK, $#  
//负责部分文件的抓取 kr5'a:F)  
**FileSplitterFetch.java %CG=mTP  
*/ *&rV}vVP^  
package NetFox; Mt(;7q@1c  
8
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import java.io.*; 4>te>[  
import java.net.*; NpF)|Ppb{  
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5t[7taLX\  
public class FileSplitterFetch extends Thread { ^ &VN=Y6z  
 uE3xzF  
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String sURL; //File URL zirnur1  
long nStartPos; //File Snippet Start Position _qq>-{-Ym  
long nEndPos; //File Snippet End Position L ^{C4}x=  
int nThreadID; //Thread's ID NPE7AdB8  
boolean bDownOver = false; //Downing is over K7]IAV  
boolean bStop = false; //Stop identical lX%e  
FileAccessI fileAccessI = null; //File Access interface {#}?-X  
S)G*+)  
<+e&E9;>6  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException q|N4d9/b  
{ ,PZ[CX;H@  
this.sURL = sURL; ]gB:ht  
this.nStartPos = nStart; q%8Ck)xz  
this.nEndPos = nEnd; \Gz 79VW  
nThreadID = id; rZG6}<Hx  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 qwHP8GU  
} _:?b-44  
?E.MP7Y#V  
A>QAR)YP  
public void run() -bQi4  
{ Zi ;7.PqL  
while(nStartPos < nEndPos && !bStop) VyxX5Lrj  
{ F=~LVaF/_  
g9:V00^<  
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try{ bDM;7fFp$  
URL url = new URL(sURL); UViWejA/*u  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ln&CB!u  
httpConnection.setRequestProperty("User-Agent","NetFox"); #F6!x3Z  
String sProperty = "bytes="+nStartPos+"-"; (c1Kg
  
httpConnection.setRequestProperty("RANGE",sProperty); I8{ohFFo  
Utility.log(sProperty); |NXe{q7{  
='\E+*[$I  
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InputStream input = httpConnection.getInputStream(); h&:6S  
//logResponseHead(httpConnection); .Sjg  
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byte[] b = new byte[1024]; h9WyQl7  
int nRead; ed4`n
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) %2EHYBQjN  
{ LFPYnK  
nStartPos += fileAccessI.write(b,0,nRead); i$S*5+  
//if(nThreadID == 1) t Ai?Bjo  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); SoL"M[O  
} {xJ<)^fD8  
=z +iI;  

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? {|7:  
Utility.log("Thread " + nThreadID + " is over!"); gWHjI3;  
bDownOver = true; q;H5S<]/  
//nPos = fileAccessI.write (b,0,nRead); }X^CH2,R  
} O(YvE  
catch(Exception e){e.printStackTrace ();} [,|;rt\o>  
} `& }C*i"  
} vON1\$bu`  
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3pI)  
//打印回应的头信息 U~YjTjbd  
public void logResponseHead(HttpURLConnection con) yh"48@L'D  
{ pl5Q2zq%  
for(int i=1;;i++) @rt}z+JF  
{ ]{PJ  
String header=con.getHeaderFieldKey(i); H5?H{  
if(header!=null) \:`-"Ou(*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ^U0)iz  
Utility.log(header+" : "+con.getHeaderField(header)); L<H6AzR+  
else EGJrnz8  
break; m005*>IY  
} /faP@Q3kR  
} y`p(}X`>  
&U0Y#11Cx  
5qQ\H}  
public void splitterStop() F
@Cxjz  
{ "IKbb7x  
bStop = true; l\1_v7s  
} &1,{.:@e  
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} (ixlFGvEq  
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/* >`u/#mrd  
**FileAccess.java g,d'&r"JWt  
*//文件访问(定位，写) b{hdEb  
package NetFox; i@hW" [A  
import java.io.*; C{P:1ELYXH  
oiNt'HQ2/  
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public class FileAccessI implements Serializable{ `]4bH,%~  
7Hzv-s  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 7=[/J*-m  
RandomAccessFile oSavedFile; R?H[{AX  
long nPos; &(YNz9L  
5Int,SX  
t6a$ZN;  
public FileAccessI() throws IOException 7/GL@H  
{ vK,.P:n  
this("",0); O t1:z:Pl  
} zTS#o#`!\  
6`U]%qx_I  
vDp|9VY?  
public FileAccessI(String sName,long nPos) throws IOException {'1e?  
{ e.?;mD  
oSavedFile = new RandomAccessFile(sName,"rw"); p|o?nI  
this.nPos = nPos;  T6N~L~J  
oSavedFile.seek(nPos); XD$;K$_7  
} ?N(opggiD  
L|
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hT?|:!ED.F  
public synchronized int write(byte[] b,int nStart,int nLen) i.G"21M  
{ !+Us)'L  
int n = -1; e]@R'oM?#`  
try{ w^wh|'u^_@  
oSavedFile.write(b,nStart,nLen); J^)=8cy  
n = nLen; "=vH,_"Ql  
} y?.l9  
catch(IOException e) ;P!x/Ct  
{ r>3y8
7  
e.printStackTrace (); ]gG&X3jaKq  
} (H-}z`sy/@  
~e#QAaXD#5  
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return n; "6zf-++%  
} ry!0~ir  
zaMKwv}BR  

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} YH/3N(],  
y(h"0A1lW  
R"V^%z;8o  
/* '5 kSr(  
**SiteInfoBean.java 't<hhjPqY  
*/ #AUV&pI[  
package NetFox; CwQRHi  
S^*ME*DDz  
3KN>t)A#  
public class SiteInfoBean { g]Fm%iy  

8KyF0r?  
5;_&C=[  
private String sSiteURL; //Site's URL !R@s+5P)U  
private String sFilePath; //Saved File's Path 2JX@#vQ4  
private String sFileName; //Saved File's Name D~LU3#n  
private int nSplitter; //Count of Splited Downloading File KG9FR*"  
8xQjJ  
%% A==_b  
public SiteInfoBean() *e}1KcJ  
{//nSplitter的缺省值为5 -G@:uxB  
//default value of nSplitter is 5 _rjB.  
this("","","",5); X>kW)c4{b  
} kb2M3%6V  
?2i\ERG?  
j#[%-nOT  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) YqNI:znm-  
{ 5BsfbLKC  
sSiteURL= sURL; T f;:C]  
sFilePath = sPath; 3}25=%;[  
sFileName = sName; n+%tu"e  
this.nSplitter = nSpiltter; +#MQ8d  
fZF.eRP'  
`(Ij@84  
} 7zEpuw  
NQqq\h  
Q3|I.I e  
public String getSSiteURL() p4M7BK:nf  
{ 0D:eP``  
return sSiteURL; L qdzqq  
} WuUT>omH  
sad[(|  
qS}pv  
public void setSSiteURL(String value) )3A%Un#B  
{ 6Z7J<0  
sSiteURL = value; VH2/  
} =]<JkWSk  
L$4nbOu\~  
\bzT=^Z;2  
public String getSFilePath() }Asp=<kCc  
{ 5B,HJax  
return sFilePath; [>wvVv  
} :Yy8Ie#  
(043G[H'.  
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public void setSFilePath(String value) Dh~Z8!*  
{ tj;<EaM  
sFilePath = value; '
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} >S=,ype~G  
9d1 Gu"  
7UA|G2Zr  
public String getSFileName() j3yz"-53e  
{ QB|D_?]  
return sFileName; rN5;W  
} JwMFu5@  
k:k!4  
BLQD=?Q
  
public void setSFileName(String value) ^":Dk5gl  
{ +K
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sFileName = value; M+Jcgb]  
} 9&p;2/H  
~sUWXw7~  
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public int getNSplitter() gg}^@h&?  
{ Z5%TpAu[  
return nSplitter; r(ufyC&  
} elzKtVw  
2-!n+#Cdf  
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public void setNSplitter(int nCount) |y~u
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{ qs'ggF1  
nSplitter = nCount; b"QeCw#v`>  
} ]53'\TH  
} AiE\PMF~{P  
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# 5C)k5  
/* Yiy|^j  
**Utility.java sg!*%*XQ  
*/ LJII7<k  
package NetFox; |`i.8  
:U$U:e  
wM#BQe3t#  
public class Utility { X=d;WT4,,  
<<:a>)6\  
#ZS8}X*S  
public Utility() TSCc=c  
{ u{"@ 4  
":upo/xN  
Wy.Xx-3W  
}  T24?1  
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//线程睡眠 #m<<]L(o8W  
public static void sleep(int nSecond) (!9ybH;T  
{ &$ /}HND  
try{ z`Cq,Sz/  
Thread.sleep(nSecond); "-;l{tL  
} EFKOElG(k  
catch(Exception e) zu-
1|XX  
{ WJN}d-S=^  
e.printStackTrace (); h]z>H~.<*  
} Jxy94y*  
} 7/$s!pV  
={a_?l%  
//日志 m;]glAtt  
public static void log(String sMsg) :5M7*s)e16  
{ xHMbtY  
System.err.println(sMsg); K@PQLL#yJp  
} z}[qk:  
x3>PM]r(V  
1~#2AdG  
public static void log(int sMsg) o>'1ct  
{ 8x J]K  
System.err.println(sMsg); +5BhC9=b  
} 0{GpO6!  
} C*I~14  
3h|:ew[  
bkgJz+u  
/* P5*~Wi`  
**TestMethod.java Ydr
/ T/1  
*/ xE4iey@\}  
package NetFox; *4tJ|m6"Y6  
CNiUHUD  
i@C$O.m(  
public class TestMethod { D/&^Y'|T  
iS"(  
01nbR+e  
public TestMethod() "7k 82dw  
{ ///xx/weblogic60b2_win.exe ~e!b81  
try{ u0(PWCi2
 
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ZAG iaq  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); JM@}+pX  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Vp'Zm:
 
fileFetch.start(); :2KLziO2  
} UA
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catch(Exception e){e.printStackTrace ();} x1}7c9nK  
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ZE*m;  
} PmGW\E[ni  
z|
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a3<.F&c+c  
public static void main(String[] args) lo*)%fy  
{ ?1?zmaS  
new TestMethod(); D{{ME8  
} %`P6a38j  
} eL-9fld/n  
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