http断点续传简单实现（java)

/* Ins`l  
**SiteFileFetch.java *:YiimOY"  
*/ *1 ]uH e  
package NetFox; EXw
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import java.io.*; oMD>Ywc-
 
import java.net.*; D},>mfzF  
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public class SiteFileFetch extends Thread {  |`f$tj  
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7 60Y$/Wz  
SiteInfoBean siteInfoBean = null; //文件信息Bean ?m=N]!n  
long[] nStartPos; //开始位置 #*uL)2nR  
long[] nEndPos; //结束位置 +p_CN*10H  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 pb?c$n$u*  
long nFileLength; //文件长度 .b&t;4q  
boolean bFirst = true; //是否第一次取文件 *_{j=sd  
boolean bStop = false; //停止标志 yAs>{6%-  
File tmpFile; //文件下载的临时信息 *{@Nq=fE  
DataOutputStream output; //输出到文件的输出流 u\x}8pn  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） *@r/5pM2}  
public SiteFileFetch(SiteInfoBean bean) throws IOException }bpQq6ZF  
{ +L|?~p`
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siteInfoBean = bean; M~#gRAUJ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); %@ODs6 R0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); mpEK (p  
if(tmpFile.exists ()) nFg~< $d  
{ !/*\}\'4  
bFirst = false; r CHl?J  
read_nPos(); )!Z*.?  
} -M~:lK]n  
else OU(8V^.  
{ GR.^glG?6  
nStartPos = new long[bean.getNSplitter()]; u+e{Mim  
nEndPos = new long[bean.getNSplitter()]; Z{Qu<vy_  
} Y3cMC)  
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} TnOggpQ6X  
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public void run() HTcb_a  
{ 2K6qY)/_  
//获得文件长度 o>i4CCU+  
//分割文件 A5RN5`}  
//实例FileSplitterFetch ]G=L=D^cK  
//启动FileSplitterFetch线程 W$;,CU.v  
//等待子线程返回 J+DDh=%  
try{ V`d,qn)i  
if(bFirst) Bz-c$me1  
{ S_4?K)n #  
nFileLength = getFileSize(); ,~$p,ALwN7  
if(nFileLength == -1) ~'H]jN  
{ n;C :0  
System.err.println("File Length is not known!"); _|\~q[ep  
} GPv1fearl  
else if(nFileLength == -2) 82qoGSD.  
{ EHIF>@TZ  
System.err.println("File is not access!"); wn, KY$/  
} DE8n+Rm  
else #PW9:_BE  
{ #ut  
for(int i=0;i<nStartPos.length;i++) ]e^&aR5f"  
{ Jk11fn;\>  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); JT7nG.9  
} G1tY)_-8[  
for(int i=0;i<nEndPos.length-1;i++) rjAn@!|:+  
{ T#Z^s~7&I  
nEndPos = nStartPos[i+1]; t?&|8SId  
} \gGW8Q;  
nEndPos[nEndPos.length-1] = nFileLength; Z'W=\rl  
} KVaiugQ  
} [z\$?VJspQ  
2'\H\|  
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//启动子线程 ^4hO  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 1~`fVg  
for(int i=0;i<nStartPos.length;i++) HTS0s\R$  
{ uc\Kg1{  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9c'xHO`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 
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nStartPos,nEndPos,i); CL;}IBd a  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OU.6bmWy|  
fileSplitterFetch.start(); JPUW6e07o  
} ,0Hr2*p  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mh#a#<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4G0m\[Du  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", (Q!}9K3  
nEndPos = " + nFileLength); |O+H[;TB6  
// fileSplitterFetch[nPos.length-1].start(); On.{!:"I/  
rJTa  
2tEkj=fA-  
//等待子线程结束 fu ,}1Mq#  
//int count = 0; 1{.|+S Z!  
//是否结束while循环 `?
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boolean breakWhile = false; u@M,qo`  
]Sz:|%JP1  
MYvY]Jx3  
while(!bStop) n\'4  
{ yYYSeH  
write_nPos(); EGS)b  
Utility.sleep(500); (gU!=F?#m  
breakWhile = true; T/~f~Zz  
Bahm]2  
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for(int i=0;i<nStartPos.length;i++) KqJs?Won  
{ 50wulGJud  
if(!fileSplitterFetch.bDownOver) 9>/4W.  
{ #x60xz  
breakWhile = false; {duz\k2  
break; 3M7/?TMw{6  
} H@>
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} i$#;Kpb`^  
if(breakWhile) 5H9z4-i x?  
break; gPO}d  
KYI/  
TDjm2R~9FS  
//count++; "m8^zg hL  
//if(count>4) P4'Q/Sj  
// siteStop(); I6av6t}  
} p)-^;=<B3  
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System.err.println("文件下载结束！"); ()?(I?I
I  
} `UaD6Mc<Mz  
catch(Exception e){e.printStackTrace ();} +GN(Ug'R  
} `HSKQ52  
_<V)-Y  
I;(L%TT `  
//获得文件长度 1n8/r}q'H  
public long getFileSize() [l??A
3G  
{ H$t_Xw==  
int nFileLength = -1; ?e4YGOe.  
try{ -@2iaQ(5a2  
URL url = new URL(siteInfoBean.getSSiteURL()); ltSU fI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); k]|~>9eY]  
httpConnection.setRequestProperty("User-Agent","NetFox"); $8h%a 8I  
o5PO=AN  
9Q.Yl&A  
int responseCode=httpConnection.getResponseCode(); vn8aFA  
if(responseCode>=400) my1@41 H  
{ l|[N42+  
processErrorCode(responseCode); *:7rdzn  
return -2; //-2 represent access is error O8r|8]
o  
} f'RX6$}\1X  
`
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};zFJ6I8  
String sHeader; _;
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for(int i=1;;i++) Bkc4TO  
{ >Cp0.A:UC#  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); uH^-R_tQ  
//Utility.log(in.readLine());  8dA~\a  
sHeader=httpConnection.getHeaderFieldKey(i); v{4$D~I  
if(sHeader!=null) K5h  
{ t=iIY`Md%  
if(sHeader.equals("Content-Length"))
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{ (%6P0*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); g$-PR37(  
break; 9.-S(ZO  
} C{rcs'  
} ~ .g@hS8>  
else zC!t;*8a  
break; $h"\N$iSq  
} 9cF[seE"0  
} ]%H`_8<gc  
catch(IOException e){e.printStackTrace ();} >tr}|>  
catch(Exception e){e.printStackTrace ();} cuITY^6  
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Utility.log(nFileLength); (?c"$|^J  
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return nFileLength; UI0VtR]   
} +O{*M9B  
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6nvz8f3*r]  
//保存下载信息（文件指针位置） b8UO,fY q  
private void write_nPos() wn%A4-%{  
{ p6V0`5@t  
try{ g3y~bf  
output = new DataOutputStream(new FileOutputStream(tmpFile)); "KpGlY?^  
output.writeInt(nStartPos.length); H7n>Vx:L-  
for(int i=0;i<nStartPos.length;i++) 0{D'n@veP  
{ C1)!f j=  
// output.writeLong(nPos); J ZS:MFA  
output.writeLong(fileSplitterFetch.nStartPos); r#a=@  
output.writeLong(fileSplitterFetch.nEndPos); oG\Vxg*  
} SqpaFWr  
output.close(); 
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} 8nV+e~-w  
catch(IOException e){e.printStackTrace ();} bY:x8fl  
catch(Exception e){e.printStackTrace ();} XRi8Gpg  
} Q197mN+0  
73;GW4,  
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//读取保存的下载信息（文件指针位置） Xx:"4l.w.  
private void read_nPos() L="}ErmK  
{ $U~]=.n  
try{ )Aqtew+A&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); h2R::/2.  
int nCount = input.readInt(); 7{*>agQh  
nStartPos = new long[nCount]; gM:".Ee  
nEndPos = new long[nCount]; q2E_A  
for(int i=0;i<nStartPos.length;i++) f ;n3&e0eC  
{ Fx.=#bVX7  
nStartPos = input.readLong(); #_p\Ie*rd  
nEndPos = input.readLong(); sO@Tf\d  
} UaeXY+O  
input.close(); :vbW  
} O\r0bUPE  
catch(IOException e){e.printStackTrace ();} ~9@UjQ^)F  
catch(Exception e){e.printStackTrace ();} kxv1Hn"`{E  
} .ioEIsg  
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\4fQMG  
private void processErrorCode(int nErrorCode) rey!{3U  
{ j#ab_3xH  
System.err.println("Error Code : " + nErrorCode); ^1];S^nD  
} G 3ptx! D  
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//停止文件下载 +M/%+l  
public void siteStop() f@!.mDm]  
{ i/Zd8+.n$  
bStop = true; P*j|.63  
for(int i=0;i<nStartPos.length;i++) 3Y$GsN4ln  
fileSplitterFetch.splitterStop(); #H~64/  
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;2QP7PrSY  
} T>W,'H  
} ]Y&VT7+Z  
//负责部分文件的抓取 +ZP7{%  
**FileSplitterFetch.java i83OOV$1J  
*/ f/?P514h  
package NetFox; (tW`=]z-<  
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import java.io.*; dR]m8mdqc1  
import java.net.*; pQB."[n  
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public class FileSplitterFetch extends Thread { Ny/MJ#Lq  
*vMn$,^0h9  
)^hbsMhO  
String sURL; //File URL ?S=mybp  
long nStartPos; //File Snippet Start Position (TM,V!G+U~  
long nEndPos; //File Snippet End Position C0Z=~Q%  
int nThreadID; //Thread's ID >vsqG=x  
boolean bDownOver = false; //Downing is over _+MJ%'>S
 
boolean bStop = false; //Stop identical ]ZS OM\}  
FileAccessI fileAccessI = null; //File Access interface mt.))#1  
Y'X%Aw;`  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >H,*H;6  
{ BiBOr}ZQ  
this.sURL = sURL; 9Mcae31  
this.nStartPos = nStart; _yR^*}xJb  
this.nEndPos = nEnd; K3uRs{l|  
nThreadID = id; u*9V&>o  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 a 1*p*dM#  
} ,a? oaPH  
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4
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public void run() tZo} ;|~'  
{ u ^RxD^=L  
while(nStartPos < nEndPos && !bStop) LDa1X2N  
{ GC'O[q+  
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try{ _@/8gPT*i  
URL url = new URL(sURL); ^LLzZnkcZ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); k9F=8q  
httpConnection.setRequestProperty("User-Agent","NetFox"); wy2 D;;  
String sProperty = "bytes="+nStartPos+"-"; Eh4=ZEX  
httpConnection.setRequestProperty("RANGE",sProperty); ?aMOZn?  
Utility.log(sProperty); d/@,@8:  
<OPArht  
<#HYqR',  
InputStream input = httpConnection.getInputStream(); hE-M$LmN@  
//logResponseHead(httpConnection); /qw.p#  

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byte[] b = new byte[1024]; =Fl^`*n  
int nRead; T51 `oZ`  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) > Nr#O  
{ Rf1x`wml  
nStartPos += fileAccessI.write(b,0,nRead); akQ7K  
//if(nThreadID == 1) Oow2>F%
_#  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BDVtSs<7  
} 8dhUBJ0_  
v &+R^iLE  
i}?>g-(  
Utility.log("Thread " + nThreadID + " is over!"); QmIBaMI#  
bDownOver = true; Z?z.?ar  
//nPos = fileAccessI.write (b,0,nRead); U/BR*Zn]*  
} Tm?#M&'  
catch(Exception e){e.printStackTrace ();} {(}By/_  
} Y <qm{e  
} 9_s`{(0?  
?bu>r=oIO]  
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//打印回应的头信息 rVsJ`+L  
public void logResponseHead(HttpURLConnection con) E4xa[iZ  
{ LreP4dRe  
for(int i=1;;i++) NaCy@  
{ <0?W{3NqI  
String header=con.getHeaderFieldKey(i); DlNX 3  
if(header!=null) igAtRX%Qx  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;*&-C9b  
Utility.log(header+" : "+con.getHeaderField(header)); Wv/=
O}  
else ete.!*=  
break; RpYERAgT  
} cCc(fF*^  
} )\^-2[;  
$,'*f?d  
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public void splitterStop() *uvQ\.  
{ )
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bStop = true; FC"8#*x  
} :eLVC7'  
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} 5*D/%]YsD  
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/* 01o4Th m  
**FileAccess.java >-{Hyx  
*//文件访问(定位，写) <rSF*  
package NetFox; ws^ np  
import java.io.*; 7J&4akT{9  
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.: Q5:  
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public class FileAccessI implements Serializable{ n{SJ_S#a.a  
A.w:h;7  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 5E_YEBO/  
RandomAccessFile oSavedFile; 2dgd~   
long nPos; 4nz35BLr  

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2)  
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public FileAccessI() throws IOException C"]^Q)aJN  
{ sUm'  
this("",0); 7T'B6`-Ox  
} r!{Up7uL  
FU<Jp3<%  
7vj2 `+r.  
public FileAccessI(String sName,long nPos) throws IOException dGTsc/$  
{ :p6M=  
oSavedFile = new RandomAccessFile(sName,"rw"); gKCX|cULY  
this.nPos = nPos; FNId;  
oSavedFile.seek(nPos); K'I#W lg  
} pFz`}?c0  
8sK9G` k  
e<q?e}>?  
public synchronized int write(byte[] b,int nStart,int nLen) eKqk= (  
{ EAby?51+  
int n = -1; F1Bq$*'N$w  
try{ y L~W.H  
oSavedFile.write(b,nStart,nLen); -1@<=jX3_  
n = nLen; $ o#V#  
} b\+`e
b8_  
catch(IOException e) [;sRV<  
{ HiJE}V;Vq  
e.printStackTrace (); $7A8/#  
} B^jc3 VsR  
J!7MZLb  
|IUWF%~^$+  
return n; U|j`e5)  
} "8zDbdK  
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, SnSW-P  
} "Os_vlapHo  
p
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;mKb]  
/* &XU
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**SiteInfoBean.java Yp2eBgo"  
*/ >~+ELVB&  
package NetFox; L\z~uo3:  
K)k<Rh[<  
VTHH&$ZNq  
public class SiteInfoBean { s=/v';5J2!  
57'4ljvYi  
2jCfT>`3  
private String sSiteURL; //Site's URL DkAAV9*  
private String sFilePath; //Saved File's Path yyy|Pw4:Z  
private String sFileName; //Saved File's Name I[X772K  
private int nSplitter; //Count of Splited Downloading File &~U ]~;@  
N_q|\S>t/  
%3''}Y5  
public SiteInfoBean() P J[`|  
{//nSplitter的缺省值为5 'a.qu9PJ  
//default value of nSplitter is 5 2Q:+
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this("","","",5); c_!cv":s  
} l0i^uMS  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ! #2{hQRu  
{ ayF\nk4b  
sSiteURL= sURL; t}/( b/VD  
sFilePath = sPath; x`)&J B  
sFileName = sName; =kG@a(-  
this.nSplitter = nSpiltter; Q>1[JW{$}  
KL Xq\{X  
[0D.K}7|  
} CF5`-wj/#  
@cB$iP=Z4  
~z;FP$U  
public String getSSiteURL() O463I.XAP  
{ -v|qZ
'  
return sSiteURL; zjoq6  
} e6RPIg  
C8i^P}y  
G+\GaY[  
public void setSSiteURL(String value) 0'?L#K  
{ UN<]N76!  
sSiteURL = value; Gjo`&#  
} u!qP  
h>OfOx/{q9  
85xR2<:  
public String getSFilePath() f^XOUh  
{ {%6`!WW[  
return sFilePath; Ck7uJI<x  
} pBA7,z"`mP  
~Vjl7G\7i  
q.`NtsW!\+  
public void setSFilePath(String value) k7A-J\  
{ h2;F
 
sFilePath = value; Bh]P{H%  
} '$zIbQ:  
RQu(Wu|m.  
$[=%R`~w  
public String getSFileName() ,]c 1A$Sr0  
{ 3 xp)a%=7  
return sFileName; pr UM-u8  
}  t[ C/  
x>`%DwoRI  
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public void setSFileName(String value) _MX>#!l  
{ .];=Pu^  
sFileName = value; (n9gkO&8"  
}
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HJYScwjQ;`  
161xAig  
public int getNSplitter() >]5P 3\AQV  
{ W#WVfr  
return nSplitter; Sa;qW3dt3E  
} tS8u  
?o#%Xs  
?zHPJLv|Y  
public void setNSplitter(int nCount) L<{i,'M  
{ ThbGQ"/  
nSplitter = nCount; zi*R`;_`,  
} naznayy  
} .
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7,9=uk>0\  
/* M,mvys$  
**Utility.java L"Olwwmk  
*/ 8k1Dj1@0z  
package NetFox; mk+B9?;cF-  
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public class Utility { { W{
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 0$fpIz  
hJ~Uf5Q  
public Utility() e|WJQd4+S  
{ ;&-k#PE]/H  
; _1 at  
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} =CVBBuVy  
}"!I[Ek> y  
//线程睡眠 q\p:X"j|  
public static void sleep(int nSecond) tQYM&6g  
{ +@k+2?] FO  
try{ eu|;eP-+d  
Thread.sleep(nSecond); 6wECo  
} !.(P~j][  
catch(Exception e) T&o(N3lW  
{ G.dTvLv  
e.printStackTrace (); /?F/9hL  
} (tw)nF  
} &/]Fc{]^$f  
{v
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//日志 )6,=f.%  
public static void log(String sMsg) '|p$)yx2  
{ HqD^B[
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System.err.println(sMsg); Pax|x15  
} MC:@U~}6  
rJbf_]^  
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public static void log(int sMsg) >!bJslWA  
{ FOy|F-j  
System.err.println(sMsg); 8=uu8-l8g  
} x$Oq0d{
T  
} n!xt5=xP{  
/Uy"M:|V1  
9}F*P669f  
/* e:n<EnT  
**TestMethod.java T@&K-UQ  
*/ Rww{:R  
package NetFox; w\i\Wp,FP  
(w/T-*  
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public class TestMethod { 8sTp`}54J  
9V@V6TvW>&  
G5aieD.#  
public TestMethod() Ne{?:h.!  
{ ///xx/weblogic60b2_win.exe '2nhv,|.U  
try{ *XbEiMJ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ]<rkxgMW>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }Nm#q@o$P  
SiteFileFetch fileFetch = new SiteFileFetch(bean); jiS_G%G  
fileFetch.start();  fc-iAj  
} ]J$eDbaEjT  
catch(Exception e){e.printStackTrace ();} >\=3:gb:  
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} 5l2 ?  
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public static void main(String[] args) Cdu4U}^H  
{ Za3]d+qm  
new TestMethod(); Zrk4*/ VY  
} :xv!N*Le  
} vK\%%H  
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