http断点续传简单实现（java)

/* /'Q2TLy=  
**SiteFileFetch.java jRNDi_u?Wb  
*/ G2!J`}  
package NetFox; eD?f|b
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import java.io.*; &AhkP=Yw  
import java.net.*; zHk7!|%Y  
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public class SiteFileFetch extends Thread { B):hm  
{`=k$1
  
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SiteInfoBean siteInfoBean = null; //文件信息Bean FgTWym_  
long[] nStartPos; //开始位置 ]Ofs,U^  
long[] nEndPos; //结束位置 Pj{Y  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 #D|n6[Y'.t  
long nFileLength; //文件长度 E>Lgf&R#W  
boolean bFirst = true; //是否第一次取文件 mk]8}+^.  
boolean bStop = false; //停止标志 raCgctYVq  
File tmpFile; //文件下载的临时信息 D%!GY1wdn  
DataOutputStream output; //输出到文件的输出流 !FHm.E_>  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） [ %6(1$Ih  
public SiteFileFetch(SiteInfoBean bean) throws IOException D2MWrX  
{ O7lFg;9c`  
siteInfoBean = bean; a+PVi  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); K| '`w.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 
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if(tmpFile.exists ()) j6DI$tV~  
{ p^*A&7d:P  
bFirst = false; 2C"[0*.[N  
read_nPos(); 1AAOg+Y@U"  
} Sgq?r-Q.  
else K410.o/=-  
{ 6Eyinv  
nStartPos = new long[bean.getNSplitter()]; aKC,{}f$m  
nEndPos = new long[bean.getNSplitter()]; vk.P| Y-;  
} NNw0 G&  
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} d34BJ<  
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public void run() }0~X)Vgm(  
{ 2VaKt4+`  
//获得文件长度 qA5 Ug  
//分割文件 ^/fasl$#  
//实例FileSplitterFetch Er@OmNT  
//启动FileSplitterFetch线程 M3Oqto
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//等待子线程返回 ,yH\nqEz  
try{ 'T(@5%Db  
if(bFirst) !Z<=PdI1Ys  
{ z#^;'nnw  
nFileLength = getFileSize(); w:07_`cH=  
if(nFileLength == -1) +l<l3uBNS  
{ B
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System.err.println("File Length is not known!"); 2(H-q(  
} 1:22y:^j  
else if(nFileLength == -2) ';;X{a  
{ cUC!'+L  
System.err.println("File is not access!"); s"B2Whe  
} e\r%"~v  
else -rlCE-S  
{ ^]MLEr!S  
for(int i=0;i<nStartPos.length;i++) 'wni.E&  
{ h&2l0|8k  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); fs0EbVDF  
} vX|
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for(int i=0;i<nEndPos.length-1;i++) \gR%PN  
{ v"-K-AQjB  
nEndPos = nStartPos[i+1]; -{A*`.[v  
} +aOQ'*g  
nEndPos[nEndPos.length-1] = nFileLength; p} {H%L  
} (!%9#  
} 9PdD=9HH  
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//启动子线程 B}0!b7!  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; q5{h@}|M  
for(int i=0;i<nStartPos.length;i++) + f,Kt9Cy  
{ 2]=`^r
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), n+S&[Y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), bX>R9i$  
nStartPos,nEndPos,i); ZdgzPs"  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xSq{pxX  
fileSplitterFetch.start(); Z):Nd9  
} '^M.;Giz  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), g cb6*@u!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); tE,& G-jU  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", EYA=fU  
nEndPos = " + nFileLength); '}$$0S.DC  
// fileSplitterFetch[nPos.length-1].start(); yt<h!k$ _P  
+`tk LvM  
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//等待子线程结束 |enb5b78  
//int count = 0; bE?X?[K  
//是否结束while循环 =YY 7V!  
boolean breakWhile = false; -\n%K
  
.FG%QFF~  
us+z8Mz  
while(!bStop) JJK-+a6cX  
{ Rqr
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write_nPos(); bvS6xU- J  
Utility.sleep(500); 3~:9ZWQ/  
breakWhile = true; N-W>tng_x  
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for(int i=0;i<nStartPos.length;i++) 0o!mlaU#  
{ nJ h)iQu  
if(!fileSplitterFetch.bDownOver) 3S" /l
  
{ ,B'fOJ.2  
breakWhile = false; c(aykIVOo  
break; 6V*,nocL_+  
} yK-DzAv  
}  { &Vt]9  
if(breakWhile) F^81?Fi.  
break; 1)5$,+~lL  
tAsap}(  
8OiCldw:HN  
//count++; S%aup(wu6  
//if(count>4) Ph8@V}80"Y  
// siteStop(); "6 ~5RCZ  
} <w`EU[y_  
;cB3D3fR.  
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System.err.println("文件下载结束！"); -Aojk8tc  
} Y&H<8ez  
catch(Exception e){e.printStackTrace ();} =#=}|Q}  
} #p"$%f5Q_  
FzNj':D  
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//获得文件长度 *2pf>UzL  
public long getFileSize() 4:-x!lt  
{ 7ug"SV6Hb  
int nFileLength = -1; )/)[}wN;j  
try{ x"!`JDsS  
URL url = new URL(siteInfoBean.getSSiteURL()); BoxtP<C"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Jy\0
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httpConnection.setRequestProperty("User-Agent","NetFox"); 6%}`!_N<Mc  
U
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int responseCode=httpConnection.getResponseCode(); @T:J<,  
if(responseCode>=400) i&?\Pp;5-j  
{ c g)>A  
processErrorCode(responseCode); 9p{n7.  
return -2; //-2 represent access is error z%#-2&i  
} L^*f$Balz  
,J,Rup">h  
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String sHeader; =fJU+N+<  
&,yF{9$G  
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for(int i=1;;i++) -+Ot'^  
{ tDRo)z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); d%.|MAE  
//Utility.log(in.readLine()); E- [Eg  
sHeader=httpConnection.getHeaderFieldKey(i); V:>r6  
if(sHeader!=null) 0N~kq-6.\  
{ ?|98Y"w  
if(sHeader.equals("Content-Length")) ul#y'iY]  
{ +80bG(I_  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); P;o{t  
break; JsNj!aeU%  
} qS9<_if2  
} D'vaK89\  
else 7B=VH r  
break; zjh:jrv~  
} W
MC\J(@.  
} T0Xm}i  
catch(IOException e){e.printStackTrace ();} ;i\N!T{>  
catch(Exception e){e.printStackTrace ();} /(*Ucv2i}T  
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3E^qh03(  
Utility.log(nFileLength); n}_}#(a  
2Z%n "z68  
-gm5Eqi  
return nFileLength; -fXQ62:S  
} 9!(%Vf>  
yo/;@}g}  
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//保存下载信息（文件指针位置） K4jHha  
private void write_nPos() &a=78Z  
{ R?{xs  
try{ kmX9)TMVO  
output = new DataOutputStream(new FileOutputStream(tmpFile)); sOlnc6  
output.writeInt(nStartPos.length); &l3(+4Sh  
for(int i=0;i<nStartPos.length;i++) ?_d6;  
{ r7oF
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// output.writeLong(nPos); }8" |q3k  
output.writeLong(fileSplitterFetch.nStartPos); f}"eN/T  
output.writeLong(fileSplitterFetch.nEndPos); ]J'TebP=L5  
} i@.Tv.NZ  
output.close(); 8toOdh  
} sv?Fx;d  
catch(IOException e){e.printStackTrace ();} HE-5e): k  
catch(Exception e){e.printStackTrace ();} Ak,JPzT  
} a#"orc j  
'~Cn+xf4]  
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//读取保存的下载信息（文件指针位置）
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private void read_nPos() %4),P(4N  
{ YI ?P@y  
try{
:;.^r,QAI  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); D\b$$z]q  
int nCount = input.readInt(); 51b%uz  
nStartPos = new long[nCount]; Y|><Ls6Q  
nEndPos = new long[nCount]; hPSMPbI  
for(int i=0;i<nStartPos.length;i++) `_)H aF>/  
{ vQyY %  
nStartPos = input.readLong(); Vx2/^MiXy  
nEndPos = input.readLong(); Yi?bY  
} @;`'s  
input.close(); +/Y2\s  
} S'8+jY  
catch(IOException e){e.printStackTrace ();} +^+'.xQ  
catch(Exception e){e.printStackTrace ();} \c4jGJ  
} s{R,- \_  
vhbHt_!u&  
^;<d<V}*  
private void processErrorCode(int nErrorCode) QMz=e  
{ c0'ryS_Z9  
System.err.println("Error Code : " + nErrorCode); D<d,9S,)  
} .FHk1~\%z^  
4qp|g'uXT  
n 5R9<A^  
//停止文件下载 '"E!av>  
public void siteStop() $uDgBZA\  
{ 'z5jnI  
bStop = true; H" `'d  
for(int i=0;i<nStartPos.length;i++) G~8BND[."  
fileSplitterFetch.splitterStop(); lbda/Zx  
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} \hgd&H0UU  
} uAeo&|&  
//负责部分文件的抓取 Zh;wQCDj  
**FileSplitterFetch.java x)Bbo9J  
*/ 9
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package NetFox; (cOe*>L;  

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import java.io.*; >-I <`y-H  
import java.net.*; K<*6E@+i  
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public class FileSplitterFetch extends Thread { mG\QF0h  
o13jd NQ-  
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String sURL; //File URL W
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long nStartPos; //File Snippet Start Position ?I6rW JcQ6  
long nEndPos; //File Snippet End Position \,G9'c 'u  
int nThreadID; //Thread's ID &~P4yI;,  
boolean bDownOver = false; //Downing is over [[IMf-]  
boolean bStop = false; //Stop identical cZxY,UvYa  
FileAccessI fileAccessI = null; //File Access interface vd[7Pxe  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _M`ZF*o=c  
{ z9ADF(J?0'  
this.sURL = sURL; adP :{j  
this.nStartPos = nStart; UA8hYWRP  
this.nEndPos = nEnd; losqc *|  
nThreadID = id; [ @eA o>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 pz /[${X  
} 7?=^0?a  
XG.[C>  
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public void run() '%rT]u3U  
{ pr#%VM[':R  
while(nStartPos < nEndPos && !bStop) }CBQdH&g;  
{ r& a[
?  
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try{ tr<fii3<  
URL url = new URL(sURL); `HRL .uX  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); e%JIqKS  
httpConnection.setRequestProperty("User-Agent","NetFox"); eT".psRiC  
String sProperty = "bytes="+nStartPos+"-"; K|Sq_/#+U  
httpConnection.setRequestProperty("RANGE",sProperty); *,$5EN  
Utility.log(sProperty); >8(i;)(3  
4]U=Y>\Sr  
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InputStream input = httpConnection.getInputStream(); T o["o!(;z  
//logResponseHead(httpConnection); }d?;kt  
GJ*IH9YR  
O%T?+1E  
byte[] b = new byte[1024]; " !EnQB=  
int nRead; M_ukG~/  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) o0R?vnA=  
{ ur}'Y^0iR  
nStartPos += fileAccessI.write(b,0,nRead);
 B(;MI`  
//if(nThreadID == 1) ?@G s7'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); oFU:]+.+D  
} f#!+l1GV  
z^QrIl/<c2  
n?@
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Utility.log("Thread " + nThreadID + " is over!"); s=n4'`y1  
bDownOver = true; ^w^e~0 S  
//nPos = fileAccessI.write (b,0,nRead); <!sLfz?  
} @Ul3J )=m  
catch(Exception e){e.printStackTrace ();} MQ!4"E5"j  
} epiviCYC  
} B"&-) (  
:8)Jnh\5  
Nu"v .]Y2  
//打印回应的头信息 |eu8;~A  
public void logResponseHead(HttpURLConnection con) yt
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{ oVpZR$  
for(int i=1;;i++) wb.yGfJ  
{ _aFe9+y  
String header=con.getHeaderFieldKey(i); {cs>Sy 4  
if(header!=null) M~2Us{
`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); kg^0%-F  
Utility.log(header+" : "+con.getHeaderField(header)); hU$o^ICH  
else |0i{z(B  
break; [MpWvLP"x  
} 7 XxZF43  
} E5^\]`9P  
>N|?>M*  
D m0)%#  
public void splitterStop() e(8hSVcl4  
{ 5
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bStop = true; xT+_JT65  
} iM<$ n2t  
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} f`hZb  
=VD],R)  
>_2~uF@pb  
/* s:tX3X  
**FileAccess.java Z<.&fZ^jS  
*//文件访问(定位，写) \\dUp>1=  
package NetFox; `7=$I~`  
import java.io.*; AmF[#)90P  
vu+g65"  
B"_O!  
public class FileAccessI implements Serializable{ 2GptK"MrD  
PMytk`<`zw  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节  cHvm
 
RandomAccessFile oSavedFile; JUr t%2  
long nPos; \78E>(`'  
qYA~Os1e  
ZHNL~=r}  
public FileAccessI() throws IOException !.6n=r8d  
{ F{ %*(U  
this("",0); @U_CnhPQq  
} ef`_ n+`  
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public FileAccessI(String sName,long nPos) throws IOException @}4aF|  
{ P2'N4?2  
oSavedFile = new RandomAccessFile(sName,"rw"); (mIjG)4t  
this.nPos = nPos; p]mN)  
oSavedFile.seek(nPos); vIRT$W' O}  
} fxd+0R;f  
'[WL8,.Q  
9f! M1  
public synchronized int write(byte[] b,int nStart,int nLen) ~$u9  
{ }:2##<"\t  
int n = -1; _qa]T'8  
try{ lKsn6c,]  
oSavedFile.write(b,nStart,nLen); F^.A~{&L  
n = nLen; fbh,V%t7  
} NT+.E[J6  
catch(IOException e) =^KgNQ   
{ |6Q5bV  
e.printStackTrace (); CGi;M=xr  
} >/A]C$?3  
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return n; *a Z1 4  
} 76!LMNf  
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} 4k225~GQ:C  
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/* O^cC+@l!4  
**SiteInfoBean.java +cH>'OXoB  
*/ UH MJ(.Wa-  
package NetFox; KUJLx  
-$:;en?  
(,h2qP-;ud  
public class SiteInfoBean { w1tM !4r  
zP44 Xhz  

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private String sSiteURL; //Site's URL 5mZ2CDV  
private String sFilePath; //Saved File's Path TLsF c^X  
private String sFileName; //Saved File's Name {5Bj*m5  
private int nSplitter; //Count of Splited Downloading File q}t]lD %C  
@:?[R&`  
d^=)n-!T  
public SiteInfoBean() tu}!:5xi  
{//nSplitter的缺省值为5 xE8?%N U  
//default value of nSplitter is 5 "K(cDVQ  
this("","","",5); ^s{Ff+]W  
} *:n7B\.  
c-k3<|H`  
P*6m~`"5  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) !.'D"Me>  
{ xqX3uq  
sSiteURL= sURL; V*@aE  
sFilePath = sPath; )NZH{G  
sFileName = sName; v Z9OJrF  
this.nSplitter = nSpiltter; WK6,K92  
-zFJ)!/?  
6Hnez@d  
} ?z.?(xZ 6  
!`e`4y*N  
5!?5S$>  
public String getSSiteURL() e6taQz@}  
{ "B{3q`(  
return sSiteURL; Onq^|r's&  
} `PbY(6CF  
DO
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public void setSSiteURL(String value) A;L ]=J  
{ N~,Ipf  
sSiteURL = value; O]tR~a  
} )jOa!E
"  
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Kzrd<h]`)  
public String getSFilePath() uP* kvi:e  
{ RxqNgun@  
return sFilePath; vQ}ZfP  
} x#`p.sfVo  
:xr^E]  
7GO9z<m)  
public void setSFilePath(String value) [_JdV(]$  
{ vi}16V84l  
sFilePath = value; Ca'BE#q  
} 44u)F@)  
&{? M} 2I  
sbmtx/%U  
public String getSFileName() +bE{g@%@+  
{ %4LoEm=U  
return sFileName; KyNu8s
k  
} p9)YRLOh.  
Q/SO%E`E  
)Dz]Pv]H'  
public void setSFileName(String value) VZt%cq  
{ Wo "s;Z  
sFileName = value; S' $;  
} CK[8y&  
[P+kQBLpL  

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public int getNSplitter() 3Rb#!tx9  
{ 4MPy}yT*  
return nSplitter; ^y@ W\  
} $U?]^  
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public void setNSplitter(int nCount) ``CM7|)>`  
{ 7"'RE95  
nSplitter = nCount; ~-k,$J?7  
} #//xOL3J  
} ]R""L<K%HF  
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JH\:9B+:L  
/* IVPN=jg?  
**Utility.java r<ww%2HTS
 
*/ LL e*|:  
package NetFox; p/(Z2N"  
#$Zx].[lc  
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public class Utility { (e'8>Pv  
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public Utility() hZ1enej)  
{ , ~ 1+MZ=  
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} inU5eronuj  
x\Q}fk?{t  
//线程睡眠 =p4n@C  
public static void sleep(int nSecond) ]t)N3n6Bc  
{ <KX9>e
 
try{ LY0f`RX*&  
Thread.sleep(nSecond); 9HJYrzf{%  
} oH w!~c7  
catch(Exception e) |^-D&C(Eu  
{ 7nT|yL?  
e.printStackTrace (); `+n0a@BVB  
} &j:e<{@  
} vCi`htm%  
/ ]8e[t>!f  
//日志 ?TpjU*Cxy  
public static void log(String sMsg) 2FuV%\p  
{ =W7-;&  
System.err.println(sMsg); gfK_g)'2U  
} +\Vw:
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:j`f%Vg~x  
h"ZIh= j@  
public static void log(int sMsg) `R2Iw I&  
{ ?+EAp"{j  
System.err.println(sMsg); =J1V?x=l@  
} pK-tj  
} }ex4dhx2M  
(W h)Ov"  
{Lal5E4-  
/* ?w(hPUd!2  
**TestMethod.java D\5+2 G  
*/ 7R6B}B?/  
package NetFox; n5C
,Z!)z  
R*pPUw\yn  
kFE9}0-  
public class TestMethod { *{VC<<`  
cRs.@U\{R\  
</;e$fh`  
public TestMethod() .hH_1Mo
8  
{ ///xx/weblogic60b2_win.exe l1T`[2  
try{ Y0g]-B  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); oIO@#   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); b\JU%89  
SiteFileFetch fileFetch = new SiteFileFetch(bean); F?'  
fileFetch.start(); .bY>++CAPA  
} vQCb?+X&  
catch(Exception e){e.printStackTrace ();} I8!>7`L  
zI[<uvxzW`  
D4c'6WGb@  
} 8a*&,W  
1av#u:jy~>  
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public static void main(String[] args) C:No ^nH>  
{ zV}:~;w  
new TestMethod(); ?<jWEz=  
} [q%`q`EG  
} 60|PVsmDm  
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