http断点续传简单实现（java)

/* XtdLKYET  
**SiteFileFetch.java 7g+]  
*/ #SNI dc>9\  
package NetFox; Fg_s'G,`  
import java.io.*; *PU,Rc()6  
import java.net.*; w[YbL2p  
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public class SiteFileFetch extends Thread { 4LJ}>e  
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SiteInfoBean siteInfoBean = null; //文件信息Bean tta0sJ8i  
long[] nStartPos; //开始位置 tdF[2@?+  
long[] nEndPos; //结束位置 aZ`agsofk  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;@~*z4U  
long nFileLength; //文件长度 :Xh`.*{EX  
boolean bFirst = true; //是否第一次取文件 |9$'?4F  
boolean bStop = false; //停止标志 5V8C+k)  
File tmpFile; //文件下载的临时信息 :9#{p^:o  
DataOutputStream output; //输出到文件的输出流 Fxx2vTV4ag  
/+O8A}  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） B?Sfcq-  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1R9?[RE  
{ w{x(YVSH  
siteInfoBean = bean; Nj&%xe>].  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^|(4j_.(e  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); pY#EXZ#   
if(tmpFile.exists ()) ;XQ lj?:  
{ X>8?p'*  
bFirst = false; Q9tE^d+%  
read_nPos();
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} )0MshgM  
else w1(06A}/
 
{ v};qMceJ  
nStartPos = new long[bean.getNSplitter()]; G<6grd5PP  
nEndPos = new long[bean.getNSplitter()]; $50"3g!Y  
} _5 tqO5'  
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} Jd"s~n<>K  
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public void run() )Hm[j)YI  
{ X`QW(rq  
//获得文件长度 NVWeJ+w  
//分割文件 bMOM`At>z  
//实例FileSplitterFetch rGGepd  
//启动FileSplitterFetch线程 HKN"$(Q  
//等待子线程返回 qpqz. {\  
try{ 810<1NP  
if(bFirst) 3N0X?* (x|  
{ kS#DKo  
nFileLength = getFileSize(); q)xl$*g
 
if(nFileLength == -1) v|2q2bz  
{ T&"dBoUq>G  
System.err.println("File Length is not known!"); _D,f4.R  
} mX.3R+t  
else if(nFileLength == -2)
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{ %7d@+ .  
System.err.println("File is not access!"); fB,1s}3Hn  
} |aAWWd5  
else b\j&!_   
{ U3+_'"  
for(int i=0;i<nStartPos.length;i++) VN-#R=D  
{ aevG<|qP  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3]OP9!\6  
} BI.k On=  
for(int i=0;i<nEndPos.length-1;i++) D6)Cjc>a  
{ S*m`'  
nEndPos = nStartPos[i+1]; ^~<Rzq!  
} n!eqzr{  
nEndPos[nEndPos.length-1] = nFileLength; [aZ v?Z  
} &DQ4=/Z  
} pkN:D+gS  
eGe[sv"k  
6#x)W  
//启动子线程 jvc?hUcLKT  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; '}pgUh_  
for(int i=0;i<nStartPos.length;i++) OG^WZ.YU  
{ ;(0(8G  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^HlLj#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), OWXye4`*  
nStartPos,nEndPos,i); %X,B-h^  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m9<%v0r  
fileSplitterFetch.start(); #+Yp^6zg  
} Ma=6kX]  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }vUlTH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); M?~<w)L}  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ncJFB,4  
nEndPos = " + nFileLength); feI[M;7u  
// fileSplitterFetch[nPos.length-1].start(); Z~phOv  
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7?!Z+r  
//等待子线程结束 -Xxu/U})%  
//int count = 0; k4F"UG-`  
//是否结束while循环 IgiF,{KE,  
boolean breakWhile = false; 1u"*09yZd  
2~&hstd%  
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while(!bStop) AXh3LA  
{ M o"JV  
write_nPos(); Jm(&G  
Utility.sleep(500); hLytKPgt  
breakWhile = true; :ONuWNY N  
lO2T/1iMTW  
2
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for(int i=0;i<nStartPos.length;i++) <{NYD.  
{ ',H$
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if(!fileSplitterFetch.bDownOver) 42J';\)oP  
{ 1ntkM?  
breakWhile = false; BU]WN7]D$  
break; Y=:KM~2hv  
} o!=lBfI  
} OSa
}8rlr'  
if(breakWhile) 4Ay`rG  
break; j.;  
^#BGA|j  
% L >#  
//count++; lsB9;I^+x  
//if(count>4) 1] %W\RHxo  
// siteStop(); /K,|k EE'n  
} JIP+ !2  
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'Uko^R)(  
System.err.println("文件下载结束！"); zD)IU_GWa  
} T}tE/  
catch(Exception e){e.printStackTrace ();} o4/I1Mq  
}  z _O,Y  
$W/+nmb)@K  
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//获得文件长度 ~3'RW0  
public long getFileSize() z#{0;t  
{ $h 08Z  
int nFileLength = -1; Gin_E&%g  
try{ q[)q|R|  
URL url = new URL(siteInfoBean.getSSiteURL()); f8LrDR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); H}
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httpConnection.setRequestProperty("User-Agent","NetFox"); Q&Z4r9+Z  
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so!w!O@@  
int responseCode=httpConnection.getResponseCode(); 1tc]rC4h  
if(responseCode>=400) h6\3vfj^f  
{ C(V[wvL  
processErrorCode(responseCode); ~[|V3h4v  
return -2; //-2 represent access is error L$29L:  
} BKC7kDK3H  
<?LfOSdMs^  
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String sHeader; `dv}a-Q)c  
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&2io^AP  
for(int i=1;;i++) TvunjTpaj  
{ [lNqT1%]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); n5Nan  
//Utility.log(in.readLine()); D!bKm[T  
sHeader=httpConnection.getHeaderFieldKey(i); n+{HNr  
if(sHeader!=null) ~K~b`|1  
{ ?$|uT  
if(sHeader.equals("Content-Length"))  <+AIt  
{ 9Z,*h-o  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {W5ydHXy  
break; eg"=H50  
} aho'|%y)  
} cO
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else H96BqNoO  
break; V~(EVF{h  
} K*R)V/B/l  
} `fBG~NDw  
catch(IOException e){e.printStackTrace ();} <w0NPrS]  
catch(Exception e){e.printStackTrace ();} \{c,,th  
_tWJXv~;  
I1Hw"G"&  
Utility.log(nFileLength); FI
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1~}m.ER  
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return nFileLength; (^sh  
} L`9TB"0R+  
UL86-R!  
]2Sfkl0  
//保存下载信息（文件指针位置） Guk.,}9  
private void write_nPos() Qq#Ff\|4u(  
{ [YC=d1F5  
try{ 9$7&URwSDI  
output = new DataOutputStream(new FileOutputStream(tmpFile)); QS3U)ZO$@  
output.writeInt(nStartPos.length); ]43alf F#  
for(int i=0;i<nStartPos.length;i++) g%`i=s&N%  
{ d"#gO,H0  
// output.writeLong(nPos); Y,k(#=wg  
output.writeLong(fileSplitterFetch.nStartPos); -Y*VgoK%  
output.writeLong(fileSplitterFetch.nEndPos); u~s Sk  
} iO!27y  
output.close(); weNzYMf%  
} "pt+Fe|@c;  
catch(IOException e){e.printStackTrace ();} Dt.0YKF  
catch(Exception e){e.printStackTrace ();} aSc{Ft/O  
} 6!P`XTTE  
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//读取保存的下载信息（文件指针位置） &J8Z@^  
private void read_nPos() hf;S]8|F  
{ Q*]$)D3n  
try{ QL2Nz@|k  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));  )|v^9  
int nCount = input.readInt();
8RVS)D''  
nStartPos = new long[nCount]; "mP&8y9F  
nEndPos = new long[nCount];
h}<0/  
for(int i=0;i<nStartPos.length;i++) Aj[?aL  
{ sU\c#|BSC"  
nStartPos = input.readLong(); z5x _fAT(  
nEndPos = input.readLong(); >A-<ZS*N  
} b9!.-^<8y  
input.close(); <3d;1o  
} Mr-DGLJ  
catch(IOException e){e.printStackTrace ();} 6yY.!HRkr  
catch(Exception e){e.printStackTrace ();} ~@{w\%(AK]  
} >DHp*$y  
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))!Bg?t-  
private void processErrorCode(int nErrorCode) ).LTts7c  
{ fX_#S|DlSG  
System.err.println("Error Code : " + nErrorCode); !)N|J$FU  
} dd]?9  
{jjSJIV1  
MhNFW'_  
//停止文件下载 j`O7=-  
public void siteStop() :M06 ;:e  
{ (ab{F5  
bStop = true; !BDUv(  
for(int i=0;i<nStartPos.length;i++) 2K;#Evn'j  
fileSplitterFetch.splitterStop(); Z1M>-[j
)  
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} BPqk"HG]T  
} cB#nsu>  
//负责部分文件的抓取 'Y.Vn P&H  
**FileSplitterFetch.java []|;qHhC~(  
*/ Y$g}XN*)E  
package NetFox; -D^L}b  
EFAGP${F  
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import java.io.*; h{k_6ym  
import java.net.*; h4/X 0@l`  
d6`OXTD  
3\AM=`  
public class FileSplitterFetch extends Thread { 4[TR0bM%  
9Y/L?km_(  
b;#\~(a  
String sURL; //File URL ZPHXzi3j  
long nStartPos; //File Snippet Start Position b
tH _HE
 
long nEndPos; //File Snippet End Position IS BV%^la|  
int nThreadID; //Thread's ID } VEq:^o.  
boolean bDownOver = false; //Downing is over RsW9:*R  
boolean bStop = false; //Stop identical Rs*vm  
FileAccessI fileAccessI = null; //File Access interface -?<4Og[^  
V >Hf9sZ  
;#TaZN  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException
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{ \?DR s  
this.sURL = sURL; k6!4Zz_8  
this.nStartPos = nStart; T$KF< =  
this.nEndPos = nEnd; C)Jn[/BD  
nThreadID = id; k;I &.H  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 EATu KLP\  
} 3$VxRz)  
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public void run() B
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{ H2
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while(nStartPos < nEndPos && !bStop) 3xNMPm  
{ Q$ri=uB;+  
>`'O7.R  
/R
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try{ p_{("zQ  
URL url = new URL(sURL); O oSb>Y/4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]"F5;p;y  
httpConnection.setRequestProperty("User-Agent","NetFox"); /qU>5;  
String sProperty = "bytes="+nStartPos+"-"; k%P;w1  
httpConnection.setRequestProperty("RANGE",sProperty); ~9=aT1S|  
Utility.log(sProperty); w8iR|TV  
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InputStream input = httpConnection.getInputStream(); b.F^vv"]]  
//logResponseHead(httpConnection); :?Y$bX}a  
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*1{S*`|cJy  
byte[] b = new byte[1024]; &<5+!cV=  
int nRead; AW,OHSXh6  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) K-eY|n  
{ "&~ 0T#  
nStartPos += fileAccessI.write(b,0,nRead); ~]'pY  
//if(nThreadID == 1) U7iuY~L  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I]nHbghcW  
} %O%=rUD  
\}_Yd8  
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Utility.log("Thread " + nThreadID + " is over!"); }LP!)|E  
bDownOver = true; zf[`~g  
//nPos = fileAccessI.write (b,0,nRead); Vp}
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} &v!WVa?  
catch(Exception e){e.printStackTrace ();} pV(lhDNoQ  
} KCuGu}  
} B*1W`f  
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//打印回应的头信息 =Z G:x<Hg  
public void logResponseHead(HttpURLConnection con) S/[E8T"  
{ *[+)7  
for(int i=1;;i++) #~L h#  
{ 9\;|x  
String header=con.getHeaderFieldKey(i); 7^*"O&y_al  
if(header!=null) awewYf$li  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /`npQg-  
Utility.log(header+" : "+con.getHeaderField(header)); 8|Y.|\  
else "YU{Fkl#j  
break; |=a}iU8  
} J#2!ZQE 3  
} BxK^?b[E8  
N#C1-*[C  
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public void splitterStop() _7T@5\b:;  
{ up'  
bStop = true; $ (=~r`O+1  
} }!>=|1fY  
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} [&?8,Q(  
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,m=4@ofX  
/* HO)/dZNU  
**FileAccess.java p&-'|'![l  
*//文件访问(定位，写) A"5z6A4WB  
package NetFox; $,>@o=)_  
import java.io.*; b6(p  
]iNEw9  
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public class FileAccessI implements Serializable{ %ir:ASk  
Va V
N  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 in`aGFQO  
RandomAccessFile oSavedFile; &sXRN&Fp  
long nPos; <#GB[kQa  
6[E|
 
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public FileAccessI() throws IOException '_k+WH&  
{ :!a2]-D}  
this("",0); '})0!g<Y  
} P|tNL}2`;  
`+:.L>5([  
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public FileAccessI(String sName,long nPos) throws IOException G`fC/Le  
{  7R#+Le)  
oSavedFile = new RandomAccessFile(sName,"rw"); *+'2?*  
this.nPos = nPos; (+<1*5BEkT  
oSavedFile.seek(nPos); E37<"(;  
} @+F4YJmB?l  
S [h];eM  
%?^6).aEK  
public synchronized int write(byte[] b,int nStart,int nLen) W!!S!JF  
{ obrl#(\P  
int n = -1; vDl- "!G1  
try{ \#-
W <  
oSavedFile.write(b,nStart,nLen); :0)3K7Q  
n = nLen; {j5e9pg1L|  
} @~c6qh  
catch(IOException e) ]ul$*  
{ x_Jwd^`t!  
e.printStackTrace (); R" )bDy?  
} uEyH2QO  
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return n; Ofm%:}LV  
} n+lOb  
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}  z@|GC_L  
;,i]w"*  
i wxVl)QL  
/* )[mwP.T=  
**SiteInfoBean.java 5zFR7/p{  
*/ dVB~Smsr  
package NetFox; ]?x: Qm'yo  
<<=WY_m}  
#P]#9Ty:  
public class SiteInfoBean { D`J6h,=2l/  
J_Ltuso  
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private String sSiteURL; //Site's URL 8]4U`\k4  
private String sFilePath; //Saved File's Path A;\7|'4  
private String sFileName; //Saved File's Name V-n&oCS+f  
private int nSplitter; //Count of Splited Downloading File &B! o,qp  
+w@M~?>  
2C{H$ A,pW  
public SiteInfoBean() U9D!GKVp  
{//nSplitter的缺省值为5 ?(*t@ {k  
//default value of nSplitter is 5 &E xYXI  
this("","","",5); x+f2GA$  
} 5JEbe   
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`n$5+a+  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) lWBb4 !l  
{ '47P|t  
sSiteURL= sURL; 2I*;A5$N1  
sFilePath = sPath; fDG0BNLY  
sFileName = sName; lds-T  
this.nSplitter = nSpiltter; 8-y{a.,u.  
x(<(t:?o  
%IC73?  
} O6IB. >T  
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public String getSSiteURL() >^XBa*4;Y  
{ 6[OzU2nB  
return sSiteURL; 3~nnCR[R  
} Fu&EhGm6  
L\y;LSTU  
6#IU*  
public void setSSiteURL(String value) /axIIfx-  
{ 3%.#}O,(  
sSiteURL = value; Or !+._3i  
} \:'%9 x  
8]&i-VFof  
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public String getSFilePath() |9~GM  
{ H[DUZ,J  
return sFilePath; >A@Y$.  
} fN'HE#W1Xa  
#j *d^j&  
PJ='tJDj  
public void setSFilePath(String value) 5/po2V9)  
{ ?nP*\8  
sFilePath = value; ]E]2o  
} 1"pw  
`,Ph/oM  
*N{emwIq  
public String getSFileName() H\XP\4#u  
{ x3PD1JUf  
return sFileName; gY@N~'f;"  
} J>u
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{uGP&c
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public void setSFileName(String value) s}N#n(  
{ * S=\
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sFileName = value; Ur*6Gi6  
} %/9 EORdeH  
v@e~k-
#  
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public int getNSplitter() 'uq#ai[5I  
{ 4.IU!.Uo  
return nSplitter; L[=a/|)TBV  
} 5Hcf;P7  
#!)n {
h+  
>
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public void setNSplitter(int nCount) ss5m/i7  
{ da (km+  
nSplitter = nCount; ?JL:CBvCp  
} C-iK$/U  
} yRo-EP  
:O(^w}sle  
jg?x&'u\)  
/* {J^lX/D  
**Utility.java d6W SL;$  
*/ c+
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package NetFox; WJ_IuX51'  
:]J Ye*  
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public class Utility { JGuN:c$  
I_A@BnM{I  
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public Utility() _Gu- uuy  
{ n5{Xj:}  
Uh][@35 p  
n_'s=]~  
} =C~/7N,lW]  
b!)<-|IK  
//线程睡眠 TC<@e<-%Sq  
public static void sleep(int nSecond) C:H
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{ Zfy
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try{ qG<$Ajiin  
Thread.sleep(nSecond); &gjF4~W]  
} qbv#I;  
catch(Exception e) < P`u}  
{ 4Z/f@ZD  
e.printStackTrace (); YX`7Hm,  
} P{u0ftyX}  
} '3?\K3S4i  
6H'HxB4  
//日志 gCxAG  
public static void log(String sMsg) 6C-z=s)P&  
{ Ox@sI:CT  
System.err.println(sMsg); 1bH;!J  
} D:Zy  
X$yN_7|+  
3"O>&Q0c  
public static void log(int sMsg) U4cY_p?  
{ z@wMc EH  
System.err.println(sMsg); hEw- O;T0  
} og0*Nt+  
} *W kIq>  
,u/aT5\_  
aJcf`<p  
/* 95z]9U
L  
**TestMethod.java ca>Z7qT!  
*/ 0X^Ke(/89  
package NetFox; ;g~TWy^o  
#y%!\1M/:A  
<A# l 35  
public class TestMethod { KG=
h&  
ezMI\r6  
?]x|Zy  
public TestMethod() k2AJXw  
{ ///xx/weblogic60b2_win.exe e/^=U7:io  
try{ #es9d3~\  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); SXy=<%ed  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >$ e9igwe  
SiteFileFetch fileFetch = new SiteFileFetch(bean); C?2'+K  
fileFetch.start(); $_
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} mVR P~:+  
catch(Exception e){e.printStackTrace ();} bP^Je&nS*  
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} YJo["Q  
E>}4$q[r  
t1%_DPD%W  
public static void main(String[] args) qs QNjt  
{ +Xemf?  
new TestMethod(); OD5m9XS  
} DS'n  
} ~}+Hgi  
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