http断点续传简单实现（java)

/* 9)Fx;GxL  
**SiteFileFetch.java m
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*/ 'nmA!s  
package NetFox; |$RNY``J  
import java.io.*; 2KlQ[z4Ir  
import java.net.*; ~}Xus?e  
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<ql,@*Y  
public class SiteFileFetch extends Thread { #b/qR^2qW  
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SiteInfoBean siteInfoBean = null; //文件信息Bean w;z7vN~/O  
long[] nStartPos; //开始位置 =[6^NR(  
long[] nEndPos; //结束位置 a`xq h2P  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ,>GHR{7>(  
long nFileLength; //文件长度 ~b f\fPm  
boolean bFirst = true; //是否第一次取文件 J:xGEa t  
boolean bStop = false; //停止标志 Ql*zl  
File tmpFile; //文件下载的临时信息 dY*q[N/pO  
DataOutputStream output; //输出到文件的输出流 "mlQ z4D)5  
@60D@Y  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） sV\_DP/l  
public SiteFileFetch(SiteInfoBean bean) throws IOException C]`uC^6g  
{ $Ome]+0  
siteInfoBean = bean; c8l>OS5i3_  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *FlPGBjJ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); "6B7EH  
if(tmpFile.exists ()) fz&B$1;8  
{ -@orIwA&  
bFirst = false; %TB(E<p`  
read_nPos(); I6>J.6luF9  
} .iXN~*+g  
else z/@_?01T=  
{ }A#IBqf5  
nStartPos = new long[bean.getNSplitter()]; 7]ieBUfS  
nEndPos = new long[bean.getNSplitter()]; $[gN#QW%  
} Y'v[2s  
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/:{%X(8  
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} $ghZ<Y2}9  
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public void run() NYm"I`5w  
{ k6G
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//获得文件长度 ys[Li.s:  
//分割文件 oMh$:jR$
 
//实例FileSplitterFetch 0RUk^  
//启动FileSplitterFetch线程 $|K d<wv  
//等待子线程返回 K1& QAXyP  
try{ / f%mYL  
if(bFirst) yI0bSu<j-  
{ 55[ 4)*  
nFileLength = getFileSize(); _(W@FS  
if(nFileLength == -1) dG\wW@}J  
{ YeH!v, >  
System.err.println("File Length is not known!"); 1
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} y<)TYr  
else if(nFileLength == -2) f:c'j`  
{ 8|u
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System.err.println("File is not access!"); Z;BS@e  
} rIyH/=;  
else ;b~ S/  
{ _;lw,;ftA  
for(int i=0;i<nStartPos.length;i++) tFN >]`Z  
{ $] 6u#5  
nStartPos = (long)(i*(nFileLength/nStartPos.length));  @MW@mP)#  
} Zt=|q
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for(int i=0;i<nEndPos.length-1;i++) Q&9
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{ Zk3Pv0c  
nEndPos = nStartPos[i+1]; 20:F$d  
} lu8G$EQI  
nEndPos[nEndPos.length-1] = nFileLength; u9lZHh#V-  
} Fq9YhR  
} Y.:R-|W  
sI ,!+  
$Y/9SD  
//启动子线程 0;Z|:\P\=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <izQ]\kL  
for(int i=0;i<nStartPos.length;i++) /{M<FVXK+|  
{ YQVo7"`%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), G6SgVaM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), )rc!irac]  
nStartPos,nEndPos,i); <p@Cx
 
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); KA3
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fileSplitterFetch.start(); d} >Po%r:  
} 4l D$'`  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
q+P@2FL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .)Tj}Im2p  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", q"2QNF'  
nEndPos = " + nFileLength); v.0qE}' |  
// fileSplitterFetch[nPos.length-1].start(); g \mE  
Fs+tcr/\[  
O zAIz+`  
//等待子线程结束 4kOO3[r  
//int count = 0; )G[byBa  
//是否结束while循环 % rBzA<  
boolean breakWhile = false; 1S{Biqi+  
_e%D/}  
w.qtSW6M+  
while(!bStop) b)wcGBS  
{ 2u{~35  
write_nPos(); c*USA eP  
Utility.sleep(500); n<?U6~F&~  
breakWhile = true; qxL\G &~  
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for(int i=0;i<nStartPos.length;i++) STKL
 
{ 2TK \pfD  
if(!fileSplitterFetch.bDownOver) uvys>]+  
{ iP:i6U]  
breakWhile = false; C.j+Zb1Z(  
break; KE?t?p  
} W.wPy@yi  
} i~B?p[  
if(breakWhile) D9rQ%|}S  
break; h~dQ5%  
#w$Y
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{Jr1K,  
//count++; `Rq=:6U;3  
//if(count>4) 8|&,JdT  
// siteStop(); qGk+4 yC  
} #2R
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bM W|:rn  
F.s$Y+c!6  
System.err.println("文件下载结束！"); ]8G 'R-8}  
} }\_.Mg^y  
catch(Exception e){e.printStackTrace ();} K#"=*p,  
} ,p2UshOmd
 
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#  
#^FM~5KK  
//获得文件长度 b,!C8rJ  
public long getFileSize() !R{IEray  
{ kG^76dAQL  
int nFileLength = -1; \!KE_7HRu  
try{ B|`?hw@g+  
URL url = new URL(siteInfoBean.getSSiteURL()); a@}.96lStD  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); iTxWXij  
httpConnection.setRequestProperty("User-Agent","NetFox"); _"DC)  
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int responseCode=httpConnection.getResponseCode(); ct+F\:e  
if(responseCode>=400) $QbJT`,mr  
{ q~{) {t;  
processErrorCode(responseCode);
c r=Q39{  
return -2; //-2 represent access is error *)^6'4=  
} manw;`Q  
4P{|H  
c~|(j \FI  
String sHeader; !Vpi1N\  
;
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U32$9"  
for(int i=1;;i++) VZ]iep  
{ UB~K/r`.|
 
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); e02Hf{eOfw  
//Utility.log(in.readLine()); .ARYCTyG  
sHeader=httpConnection.getHeaderFieldKey(i); F
`=p/IAJK  
if(sHeader!=null) 0d2P   
{ S!K<kn`E3  
if(sHeader.equals("Content-Length")) U1\EwBK8*T  
{ jaS<*_~#R
 
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ammi4k/  
break; ~M~DH-aX   
} 5SFr E`  
} :s)cTq|3  
else If'q8G3]-  
break; 1UQ,V`y  
} xU'z>y4V$  
} 2H%9l@}u  
catch(IOException e){e.printStackTrace ();} 18$d-[hX  
catch(Exception e){e.printStackTrace ();} H3wJ5-q(  
q@.>eB'92P  
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Utility.log(nFileLength); VuLb9Kn  
\zd[A~!  
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return nFileLength; A}fm).Wp@  
} 7cc^
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FDoPW~+[  
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//保存下载信息（文件指针位置） PRfq_:xy  
private void write_nPos() .Ys e/oEo  
{ &%J{uRp  
try{ , ['}9:f9  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 4U2{1aN`  
output.writeInt(nStartPos.length); lpT&v;$`  
for(int i=0;i<nStartPos.length;i++) &M-vKc"d  
{ 8W3zrnc  
// output.writeLong(nPos); 5OM#_.p  
output.writeLong(fileSplitterFetch.nStartPos); le*+(aw  
output.writeLong(fileSplitterFetch.nEndPos); :N8n6)#1=  
} Bzz|
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output.close(); qrMED_(D  
} ~+.=  
catch(IOException e){e.printStackTrace ();} w_"d&eYdg0  
catch(Exception e){e.printStackTrace ();} `2>p#`  
} tSy 9v  
|JkfAnrN$I  
%9YY \a {  
//读取保存的下载信息（文件指针位置） "#)|WVa=BM  
private void read_nPos() u|KjoO   
{ Na@bXcz)  
try{ Kebr>t8^  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); hpf0fU  
int nCount = input.readInt(); ,
#;hI{E  
nStartPos = new long[nCount]; MkW=sD_  
nEndPos = new long[nCount]; V7,dx@J-  
for(int i=0;i<nStartPos.length;i++) Gf8^nfr  
{ 2: QT`e&  
nStartPos = input.readLong(); l]G iz&  
nEndPos = input.readLong(); 628iN%[-  
} #WjQ'c:  
input.close(); $:I{  
} T]wC?gQG  
catch(IOException e){e.printStackTrace ();} 'VVU-)(8  
catch(Exception e){e.printStackTrace ();} )qx;/=D  
} G]h_z|$K  
B=KrJ{&!  
;*?>w|t}w  
private void processErrorCode(int nErrorCode) SM~~:  
{ cfmLErkp  
System.err.println("Error Code : " + nErrorCode); ,h=a+ja8  
} aiPm.h>  
B}[CU='P*  
=!-}q  
//停止文件下载 zS:2?VXxq  
public void siteStop() J0V m&TY  
{ ILr=<j  
bStop = true; +-tFgXG  
for(int i=0;i<nStartPos.length;i++) +cfcr*  
fileSplitterFetch.splitterStop(); 8SpG/gl"  
{ 
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;PaU"z+Je~  
} -sJ1q^;f@  
} !aSj1 2J  
//负责部分文件的抓取 !4Aj#`)  
**FileSplitterFetch.java 7R:j^"I@  
*/ ezw*Lo!  
package NetFox; "R5G^-<hp  
YM`T"`f  
*zUK3&n~I  
import java.io.*; ?OW!D?  
import java.net.*; *AV%=  
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D>k(#vYKB  
public class FileSplitterFetch extends Thread { XQ~Xls%]   
z~2{`pET  
W=HvMD  
String sURL; //File URL lU 62$2  
long nStartPos; //File Snippet Start Position uxyj6(  
long nEndPos; //File Snippet End Position 7c"Csq/]I  
int nThreadID; //Thread's ID $'KQP8M+  
boolean bDownOver = false; //Downing is over c:7V..  
boolean bStop = false; //Stop identical e6MBy\*n  
FileAccessI fileAccessI = null; //File Access interface =?$~=1SL+  
(Y'cxwj%  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ]I)ofXu]  
{ L\UPM+tE  
this.sURL = sURL; Yuw:W:wY  
this.nStartPos = nStart; ?j8!3NCl}  
this.nEndPos = nEnd; 7j)ky2r#  
nThreadID = id; GXxI=,L8F  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "gy&eR>  
} hDi~{rbmc  
56JQ h  
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public void run() 6=n|Ha  
{ T1qbb*  
while(nStartPos < nEndPos && !bStop) .X%J}c$  
{ |&"aZ!Kn  
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FzEs1hpl  
try{ 9287&+,0r  
URL url = new URL(sURL); M6
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <y8oYe_!  
httpConnection.setRequestProperty("User-Agent","NetFox"); Tr_gc~  
String sProperty = "bytes="+nStartPos+"-"; $F^VtCx2&  
httpConnection.setRequestProperty("RANGE",sProperty); F%<*a,m6g  
Utility.log(sProperty); f2[R2sto@  
q{`1[R  
M?YNK]   
InputStream input = httpConnection.getInputStream(); ="78#Wfj2  
//logResponseHead(httpConnection); MO$yst?fK  
W:
8MqVm34  
)T"Aji-hy  
byte[] b = new byte[1024]; ;[;WEA  
int nRead; t@R[:n;+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) wxqX42v  
{ el`?:dY H  
nStartPos += fileAccessI.write(b,0,nRead); y>}r  
//if(nThreadID == 1) zHA::6OgPN  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nHm29{G0  
} l6#Y}<tq  
9vP;i= fr  
7)QZ<fme  
Utility.log("Thread " + nThreadID + " is over!"); Xuu&`U~%  
bDownOver = true; "LlQl3"=  
//nPos = fileAccessI.write (b,0,nRead); &
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} 4/~x+tdc  
catch(Exception e){e.printStackTrace ();} Jy/< {7j  
} lv=q( &  
} b5H}0<  
{Z k^J  
<qfAW?tF  
//打印回应的头信息 %W9R08
`  
public void logResponseHead(HttpURLConnection con) ~<!j]@.  
{ e1a\--  
for(int i=1;;i++) O6NH  
{ .Pj<Pe  
String header=con.getHeaderFieldKey(i); !O%!A<3  
if(header!=null) %:'G={G`QH  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); yVnG+R&  
Utility.log(header+" : "+con.getHeaderField(header)); aC`>~uX##V  
else k*?T^<c3  
break; D&pn@6bB  
} @Pk<3.S0  
} B>c$AS\5y  
{,JO}Dmu5  

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public void splitterStop() ;Tnid7:S  
{ `$Rgn3  
bStop = true; 1s(T#jh  
} g ptf*^s  
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} SI~jM:S}  
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vN^.MR+<  
/* V3ht:>c9qs  
**FileAccess.java ~D3S01ecM  
*//文件访问(定位，写) s>o#Ob@4'  
package NetFox; )KE  
import java.io.*; &*>.u8:r  
]O@iT= *3  
te(H6c#0  
public class FileAccessI implements Serializable{ uCr& `  
?D.+D(  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 _M/N_Fm  
RandomAccessFile oSavedFile; #?w07/~L  
long nPos; .2c/V  
I+H~ 5zq.  
sR1_L/.  
public FileAccessI() throws IOException 5?;<^J  
{ 7tlK'j'  
this("",0); k5E2{&wZ  
} 3
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public FileAccessI(String sName,long nPos) throws IOException J{b#X"i  
{ ,5v'hG  
oSavedFile = new RandomAccessFile(sName,"rw"); =xm7i#1  
this.nPos = nPos; P4Pc;8T@!  
oSavedFile.seek(nPos); g6%]uCFB  
} nC p/.]Y*  
#4mRMsW5"  
@CzFzVmF"  
public synchronized int write(byte[] b,int nStart,int nLen) \ji\r]k  
{ N_K9H1r  
int n = -1; 4&cQW)  
try{ I}bu  
oSavedFile.write(b,nStart,nLen); t9U6\ru  
n = nLen; :@i+yN cV  
} aI&~aezmN  
catch(IOException e) 4,LS08&gh  
{ _jG|kjFTc  
e.printStackTrace (); <VhmtT%7  
} J[:#(c&c!1  
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ISC>]`  
return n; &Tt7VYJfIV  
} -+@N/d5  
ij0I!ilG4  
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} pYQSn.`V~  
#aL.E(%  
@/kI;8  
/* ]:Ep1DIMl  
**SiteInfoBean.java K9EHT-  
*/ dP_QkO  
package NetFox; >hNSEWMY`  
CWkWW/ZI  
1rZ E2  
public class SiteInfoBean { KsOSPQDGE  
)!27=R/  
2*V%S/cck  
private String sSiteURL; //Site's URL dPu
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private String sFilePath; //Saved File's Path _MC',p&  
private String sFileName; //Saved File's Name Eh8GqFEM  
private int nSplitter; //Count of Splited Downloading File K>+ v" x  
uuEvH<1  
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public SiteInfoBean() =F_uK7W  
{//nSplitter的缺省值为5 s?}qi
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//default value of nSplitter is 5 5z0Sns  
this("","","",5); A^,ul>!  
} ,JdBVt  
EM@|^47$  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) r5s{t4 ;Ch  
{ -Ct+W;2  
sSiteURL= sURL; c9[{P~y  
sFilePath = sPath; 3iw3:1RZUZ  
sFileName = sName; e=VSO!(rY  
this.nSplitter = nSpiltter; <~uzHg%Y  
NxnRQS  
tZ[9qms^_  
} d[l8qaD  
pP.`+vPi  
(9]1p;  
public String getSSiteURL() $O\m~r4  
{ 1R@G7m  
return sSiteURL; #9TL5-1y  
} Se!w(Y&  
J'WzEgCnU  
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public void setSSiteURL(String value) D,.`mX  
{ ub8d]GZJ  
sSiteURL = value; R-zS7Jyox  
} ,Dv*<La`\  
\uHC9}0  
|Jx:#OM  
public String getSFilePath() ltNI+G  
{ W]Xwt'ABz  
return sFilePath; %R4 \[e  
} DtBvfYO8)>  
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public void setSFilePath(String value) !q$VnqFk
 
{ &w^9#L  
sFilePath = value; | t:UpP  
} l\L71|3"g  
392(N(  
UUz{Qm%  
public String getSFileName() ;V~x[J|x  
{ olQP>sa  
return sFileName; W>!:K^8]  
} dn'|~zf.  
K@n-#  
m#WXZr  
public void setSFileName(String value) ep
3VJ"^  
{ 6k@F?qHS  
sFileName = value; ]/h$6mrL  
} '['%b  
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nL^7t7mp  
public int getNSplitter() `%[m%Y9h  
{ c86?-u')  
return nSplitter; <=|^\r !}&  
} 1:<n(?5JI  
p}==aNZK  
"a;$uW@.6  
public void setNSplitter(int nCount) O6$,J12l  
{ S^~"#  
nSplitter = nCount; , SUx!o  
} F}mt *UcMG  
} b'^<0c  
E2}X[EoBF  
KJ/Gv#Kj  
/* &jEw(P&_  
**Utility.java
b&E"r*i|  
*/ M3UC9t9]  
package NetFox; J0k!&d8  
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public class Utility { 8)iI=,T*  
zytW3sTZA  
MA9E??p3\  
public Utility() +(Hp ".gU  
{ s w>B  
1Bs t|  
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} _T.`+0UV  
8[@Y`j8  
//线程睡眠 ~a V5  
public static void sleep(int nSecond) zE8_3UC  
{ 3s]o~I2x  
try{ tol-PJS}  
Thread.sleep(nSecond); q@S\R 7R  
} \5N\NN @J  
catch(Exception e) ,e 7 ~G  
{ }t(5n$go6  
e.printStackTrace (); ;K l'[~z  
} bRFZ:hu l  
} ~~WY?I-  
)RFY2}  
//日志 %! S
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public static void log(String sMsg) lhE]KdE
3  
{ "}0QxogYE  
System.err.println(sMsg); f[NxqNn
 
} G?~Yw'R^8  
#Q_Scxf  
!j #8zN  
public static void log(int sMsg) Qg1kF^=  
{ dw}ge,bBic  
System.err.println(sMsg);
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} vfT @;`  
} iX2exJto  
V
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3`3my=  
/* Su@V
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**TestMethod.java 8:I-?z;S  
*/ StNA(+rT  
package NetFox; &!:mL],  
u9q#L.Ij  
U7zd7O  
public class TestMethod { `|nJAW3  
v8\_6}*I  
b~ig$!N]  
public TestMethod() \ D>!&  
{ ///xx/weblogic60b2_win.exe m/g[9Y  
try{ USgO`l\}4  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /i!/)]*-  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); B|^=2 >8s  
SiteFileFetch fileFetch = new SiteFileFetch(bean); P"Q6wdm  
fileFetch.start(); dZkKAK:v  
} 1'&HmBfcb  
catch(Exception e){e.printStackTrace ();} ze8MFz'm  
~r})&`5  
y9i+EV  
} X+\=dhn69  
#Ph8?  
?` ebi|6  
public static void main(String[] args) "_rpErm }  
{ ^Kl<<pUaV
 
new TestMethod(); T.{]t6t$U  
} HD$r<bl  
} m=iKu(2xRq  
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