http断点续传简单实现（java)

/* +!)_[ zo  
**SiteFileFetch.java avW33owb@  
*/ r9n:[A&HE  
package NetFox; h)Ol1[y`  
import java.io.*; (Ta(Y=!uq  
import java.net.*; hG>kx8h  
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public class SiteFileFetch extends Thread { 7m8(8$-
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}^2'@y!(  
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SiteInfoBean siteInfoBean = null; //文件信息Bean M2I*_pI  
long[] nStartPos; //开始位置 ]I\9S{?  
long[] nEndPos; //结束位置 i5gNk)D  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 (wf3HEb_  
long nFileLength; //文件长度 D9!$H!T _  
boolean bFirst = true; //是否第一次取文件 mDO! o  
boolean bStop = false; //停止标志 8`_tnARIX  
File tmpFile; //文件下载的临时信息 #3?}MC  
DataOutputStream output; //输出到文件的输出流 *Tr9pq%m  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Q 3/J@MC  
public SiteFileFetch(SiteInfoBean bean) throws IOException AF>t{rw=/  
{ u:H:N]  
siteInfoBean = bean; a%5/Oc[[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )KOIf{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \\;y W~  
if(tmpFile.exists ()) ] !n3j=*  
{ yW&ka3j
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bFirst = false; #7@
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read_nPos(); XSGBC:U)l  
} FH%M5RD  
else -b|"%e<'  
{ dWdD^>8Ef  
nStartPos = new long[bean.getNSplitter()]; :6]qr86  
nEndPos = new long[bean.getNSplitter()]; C[5dhFZ  
} =}YX I  
*%*Bo9a/  
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} ?!O4ia3nFk  
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public void run() -hc8IS
 
{ G#M0 C>n  
//获得文件长度 3gnO)"$  
//分割文件 _3.rPS,s  
//实例FileSplitterFetch 6b9J3~d\E  
//启动FileSplitterFetch线程 E^$8nqCL:  
//等待子线程返回 ".2d{B  
try{ 7D1$cmtH  
if(bFirst) %k~ezn  
{ 4c[/%e:\-  
nFileLength = getFileSize(); v\_\bT1  
if(nFileLength == -1) E^Q J50  
{ |* ^LsuFb  
System.err.println("File Length is not known!"); Cy*.pzCi  
} g>k?03;  
else if(nFileLength == -2) sG)aw`_j  
{ FBbaLqgVF{  
System.err.println("File is not access!"); sN2m?`?"G  
} `- (<Q;iO  
else 'GT^araz  
{ tP"6H-)X&  
for(int i=0;i<nStartPos.length;i++) v5@M 34  
{ r)OiiD"  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); A=IpP}7J  
} .FC+  
for(int i=0;i<nEndPos.length-1;i++) p|8ZHR+  
{ r7L.W
  
nEndPos = nStartPos[i+1]; ;8dffsyq  
} #9Ect@?N0  
nEndPos[nEndPos.length-1] = nFileLength; <i]0EE}%  
} R PoBF~>  
} :`Ut.E~.  
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u&^KrOM@#  
//启动子线程 AI|+*amTd  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; nj1o!+9>$  
for(int i=0;i<nStartPos.length;i++) @d^Z^H*Yv  
{ Y;%LwDC  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), P/.<sr=2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), miu?X!  
nStartPos,nEndPos,i); =&,T@5&-=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); MfHOn YV  
fileSplitterFetch.start(); `GdH ,:S>  
} {-8Nq`w  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8Znr1=1   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ft1#f@b.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", yCav;ZS_  
nEndPos = " + nFileLength); Wbei{3~$Y"  
// fileSplitterFetch[nPos.length-1].start(); y_}vVHT,  
~!qnKM>[  
IZ7o6Etti  
//等待子线程结束 VsAJ2g9L  
//int count = 0; [rWBVfm  
//是否结束while循环 Yj/o17  
boolean breakWhile = false; }7(+#ISK6  
!Q15qvRS  
jH
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while(!bStop) Nr~!5XO  
{ BDvkY  
write_nPos(); 6V%}2YE?X  
Utility.sleep(500); _,)_(R ,h  
breakWhile = true; GIH{tr1:<  
(${ #l  
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for(int i=0;i<nStartPos.length;i++) #UoFU{6tM  
{ ye9GBAj /  
if(!fileSplitterFetch.bDownOver) ;!A8A4~nu  
{ yRyXlZC  
breakWhile = false; gac31,gH  
break; ~`FRU/@r  
} @jm+TW
  
} ; F'IS/ttX  
if(breakWhile) T`":Q1n  
break; *3fl}l  
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hmGlGc,lf  
//count++; c-(RjQ~M5  
//if(count>4) e'A_4;~@s  
// siteStop(); PL{lYexJ  
} * @]wT'  
<<u]WsW{C  
M$%ON>Kq  
System.err.println("文件下载结束！"); LYECX  
} rIPfO'T?  
catch(Exception e){e.printStackTrace ();} ,HTwEq>-G  
} @i!+Z  
X
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v1~l=^4&  
//获得文件长度 6Q7=6  
public long getFileSize() e}yF2|0FD  
{ 7;q0'_G  
int nFileLength = -1; GqL&hbpi  
try{ p-{ 4 $W  
URL url = new URL(siteInfoBean.getSSiteURL()); =Pw{1m|k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T$"~Vu  
httpConnection.setRequestProperty("User-Agent","NetFox"); @[9  
gi,7X\`KQ  
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int responseCode=httpConnection.getResponseCode(); STjb2t,a  
if(responseCode>=400) z0/+P  
{ h<3b+*wYJC  
processErrorCode(responseCode); Jw}t~m3  
return -2; //-2 represent access is error 7V::P_aUY  
} NzyEsZ]$  
f|B\Y/*X  
i /[{xRXiR  
String sHeader; hbJy<e1W  
]^>Inh!  
vc|tp_M67  
for(int i=1;;i++) "KK}}$>  
{ 1q!k#Cliu  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 8Pa*d/5Y(  
//Utility.log(in.readLine()); eR5q3E/;G  
sHeader=httpConnection.getHeaderFieldKey(i); TxK v!-1  
if(sHeader!=null) ,jC~U s<  
{ {z_cczJ-  
if(sHeader.equals("Content-Length")) 4z5qXI/<m4  
{ W?zj^y[w  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); <tbs,lcw;  
break; YX,;z/Jw2  
} ;W5.g8  
} @4*eH\3  
else RyX11XU  
break; liPrxuP`  
} RP~67L  
} jbS@6 *_  
catch(IOException e){e.printStackTrace ();} yO7H!}y_  
catch(Exception e){e.printStackTrace ();} 8BAe6-*S8  
4K:Aqqhds  
Kn$E{F\  
Utility.log(nFileLength); >Vq07R  
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9'H:pb2  
return nFileLength; 
3n7>qZ.d  
} C<a&]dN/  
U`~L}w"  
tE-bHu370  
//保存下载信息（文件指针位置） J#wf`VR%  
private void write_nPos() -:_3N2U=+  
{ _X?_|!;J  
try{ [AFR \{  
output = new DataOutputStream(new FileOutputStream(tmpFile)); !U4YA1>>  
output.writeInt(nStartPos.length); )UU`uzU;u  
for(int i=0;i<nStartPos.length;i++) aj1g9y  
{ 3;z1Hp2X  
// output.writeLong(nPos); g; -3  
output.writeLong(fileSplitterFetch.nStartPos); ~u0<c:C^  
output.writeLong(fileSplitterFetch.nEndPos); 9wfE^E1  
} `*Wg&u  
output.close(); Es}`SIe/  
} #o~C0`8!B=  
catch(IOException e){e.printStackTrace ();} t;3).F  
catch(Exception e){e.printStackTrace ();} ~FAk4
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} `j
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9UteD@*  
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//读取保存的下载信息（文件指针位置） J=kf KQV  
private void read_nPos() [C-FJ>=S  
{ ^ux'-/  
try{ be-HF;lZe'  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {C]tS5$Z  
int nCount = input.readInt(); 7ieAd/:_  
nStartPos = new long[nCount]; Zr6.
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nEndPos = new long[nCount]; j7I?K :op=  
for(int i=0;i<nStartPos.length;i++) O`_, _  
{ hd/'>]  
nStartPos = input.readLong(); LrdE
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nEndPos = input.readLong(); 3e-E/6zH6  
} 4k{xo~+%,  
input.close(); %'. x vC
  
} QS4~":D/C  
catch(IOException e){e.printStackTrace ();} q3v5gz^t  
catch(Exception e){e.printStackTrace ();} l%0-W  
} fY=:geB  
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private void processErrorCode(int nErrorCode) Hv' OO@z  
{ 
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System.err.println("Error Code : " + nErrorCode); M.qv'zV`xG  
} 8ZjRMr}  
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gCRPaF6  
//停止文件下载 ]M"U 'Z  
public void siteStop() C^_m>H3b  
{ ;ioF'ov  
bStop = true; 'F/uD1;  
for(int i=0;i<nStartPos.length;i++) ~-sG&u>  
fileSplitterFetch.splitterStop(); PN J&{4wY  
Ed-3-vJej6  
5K&A2zC|  
} =l] lwA-  
} ;1_3E2E$  
//负责部分文件的抓取 5D7k[+6  
**FileSplitterFetch.java V+U89j1g  
*/ $Dv5TUKw  
package NetFox; ,j(E>g3  
^e\$g2)
.  
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import java.io.*; @a=jSB#B  
import java.net.*; y5^OD63s  
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public class FileSplitterFetch extends Thread { `q |
)_  
8B!QqLqK  
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String sURL; //File URL =jxy4`oF  
long nStartPos; //File Snippet Start Position &?xtmg<d  
long nEndPos; //File Snippet End Position /Q89y[  
int nThreadID; //Thread's ID t-}IKrbv  
boolean bDownOver = false; //Downing is over A|U0e`Iw  
boolean bStop = false; //Stop identical VKlC`k8L  
FileAccessI fileAccessI = null; //File Access interface M*Q}^<E*  
PAC=LQn&  
/m^G 99N  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 68<W6z  
{  %(K}1[  
this.sURL = sURL; *p\fb7Pu_3  
this.nStartPos = nStart; 7>0/$i#'Vl  
this.nEndPos = nEnd; F$:UvW@e1  
nThreadID = id; cc1M9kVi  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 sint":1FC  
} /3sX>Rj  
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public void run() (4C)] RHQ  
{ !\Cu J5U  
while(nStartPos < nEndPos && !bStop) c7WOcy@M  
{ _[l&{,  
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try{ ;K4uu<e\  
URL url = new URL(sURL); U.I7p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *Utx0Me  
httpConnection.setRequestProperty("User-Agent","NetFox"); ' eWG v  
String sProperty = "bytes="+nStartPos+"-"; ~,8#\]xR  
httpConnection.setRequestProperty("RANGE",sProperty); pbwOma2  
Utility.log(sProperty); mjk<FXW  
cbzS7q<)  
5'w&M{{9  
InputStream input = httpConnection.getInputStream(); W(-son~I  
//logResponseHead(httpConnection); DPmY_[OAE  
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byte[] b = new byte[1024]; OI6m>XH?  
int nRead; Q{miI N  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) =`CK`x  
{ G<`(d@g  
nStartPos += fileAccessI.write(b,0,nRead); o>&pj  
//if(nThreadID == 1) GyFA1%(o  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q
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} CalWJ  
\DD4=XGA  
A\E ))b9+  
Utility.log("Thread " + nThreadID + " is over!"); Z;0<k;#T(p  
bDownOver = true; ^bdXzj
f  
//nPos = fileAccessI.write (b,0,nRead); H_1&>@ 3  
} wCj)@3F  
catch(Exception e){e.printStackTrace ();} ?T|0"|\"'  
} +-5YmN'  
} iorQ/(  
E7B?G3|z3  
z|(<Co8#.  
//打印回应的头信息 #)S&Z><
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public void logResponseHead(HttpURLConnection con) z XUr34jF  
{ #nZPnc:  
for(int i=1;;i++) QWC C  
{ ;!3: 3;  
String header=con.getHeaderFieldKey(i); l=$?#^^ /  
if(header!=null) Ah
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); 'coY`B; 8  
Utility.log(header+" : "+con.getHeaderField(header)); 'jy
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else 2zX9c<S=5  
break; (>lH=&%zj  
} P1Iy>%3  
} FNo.#Z5+b  
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m  
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public void splitterStop() )6o%6$c  
{ :C={Z}t/F  
bStop = true; j|XL$Q  
} }-9 c1&m  
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s |o(~2j  
} $Ny:At  
nm%7e!{m  
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/* "2 :zWh7|  
**FileAccess.java y!q`o$nK  
*//文件访问(定位，写) GSfU*@L3  
package NetFox; f<'D?d)L^  
import java.io.*; {)Shc;Qh  
# 00?]6`z  
rQ&XHG>Q*  
public class FileAccessI implements Serializable{ \#F>R,  
s;sr(34  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Zv8_<>e  
RandomAccessFile oSavedFile; ni<\AF]`  
long nPos; :H:+XIgoR  
E#!.;AQ  
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public FileAccessI() throws IOException x]4>f[>*>  
{ N-45LS@  
this("",0); :0bjPQj  
} <5G4|l  
>Qg-dJt[  
E;q+u[$  
public FileAccessI(String sName,long nPos) throws IOException K;>9K'n  
{ [EK^0g
 
oSavedFile = new RandomAccessFile(sName,"rw"); I<Mb/!TQ  
this.nPos = nPos; 
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oSavedFile.seek(nPos); g(G$*#}o8A  
} 5s>>] .%  
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@![1W@J  
public synchronized int write(byte[] b,int nStart,int nLen) 6l2Os $  
{ +HgyM0LFg  
int n = -1; Mf7 [@#$  
try{ `_BmVms  
oSavedFile.write(b,nStart,nLen); r>sXvzv  
n = nLen; t oM+Bd:Y  
} :Smyk.B2!  
catch(IOException e) l j+p}dt  
{ ,4;'s  
e.printStackTrace (); Zb'a+8[  
} 46B'Ec  
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return n; A.RG8"  
} 8>
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} 7I;0%sVQ{  
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/* U r8JG&,  
**SiteInfoBean.java *r7%'K{C  
*/ /"^XrVi-  
package NetFox; o"kL,&  
{!!8 *ix  
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public class SiteInfoBean { }FX:sa?5  
%zhSSB=BJ  
Pu'NSNT  
private String sSiteURL; //Site's URL b'vIX< g  
private String sFilePath; //Saved File's Path j(M.7Z7^  
private String sFileName; //Saved File's Name  @l&{ j  
private int nSplitter; //Count of Splited Downloading File ZmJ<FF4  
R3.8Dr0f  
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public SiteInfoBean() A7T(p7pP  
{//nSplitter的缺省值为5 x&$8;2&.  
//default value of nSplitter is 5 LKZv#b[h  
this("","","",5); ^Cj3\G4,  
} m@)Ya*=<  
[fs.D /  
AtqsrYj  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) O(:/&`)  
{ J<&?Hb*|  
sSiteURL= sURL; Zq:c2/\c}  
sFilePath = sPath;  sHOBT,B  
sFileName = sName; f=Oj01Ut*  
this.nSplitter = nSpiltter; IBW-[lr7  
A-h[vP!v|  
K?yMy,9%Yw  
} BHU=TK@GR  
*@WBaN+  
R'oGsaPB2  
public String getSSiteURL() 08g2? 5w"  
{ j@4]0o  
return sSiteURL; Sae*VvT6  
} M} +s_h
9  
V}FH5z |  
CX; m8  
public void setSSiteURL(String value) (%9J(4  
{ ViUx^e\
  
sSiteURL = value; u]]mbER*t#  
} ET%F+  

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public String getSFilePath() *9`k$'  
{ *=Ma5J.  
return sFilePath; dki3(  
} 'L^M"f^I  
*g4Uo{  
{J/+KK  
public void setSFilePath(String value) Vw`%|x"Xz  
{ 3w/z$bj  
sFilePath = value; ;Q[E>j?w=  
} 9j5B(_J^  
"S>VqvH3  
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public String getSFileName() $MM[`^~  
{ rAD4}A_w  
return sFileName; ojVN-*5  
} >}d6)s|   
g O8~$Aj  
c57`mOe/b  
public void setSFileName(String value) },O7NSG<o  
{ OK z5;#S=  
sFileName = value; AU;Iif6  
} 6}*4co  
}T53y6J#  
]
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public int getNSplitter() -tp3qi  
{ 8 v da"  
return nSplitter; !HXyvyDN  
} e'fo^XQn[  
-:Q"aeC5  
dx.Jv/Mb  
public void setNSplitter(int nCount) BM87f:d  
{ D<[kbt5^7  
nSplitter = nCount; EV;"]lC9  
} `Y,Rk  
} M1*x47bN  
~b[5}_L=>  
MI`<U:-lP  
/* H8E#r*"-m  
**Utility.java <B+ WM  
*/ K'[kl'  
package NetFox; >=3oe.$)  
sjHcq5#U!  
]@l;;Sp  
public class Utility { ^ JU#_  
)1<GSr9  
1([?EfC  
public Utility() Io('kCOR;  
{ S=$ \S9  
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= jTC+0u  
} T|5uywA|  
MQX9BJ%  
//线程睡眠 `mquGk|)  
public static void sleep(int nSecond) ]oKHS$W9  
{ ];u nR<H  
try{ {k']nI.>  
Thread.sleep(nSecond); XMLl>w2z  
} NH'Q
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catch(Exception e) _V3}F1?W  
{ $;)A:*e  
e.printStackTrace (); LXRIo2ynuw  
} 98CS|NEe  
} )\{]4[9N  
i,l$1g-i  
//日志 C0&ZQvvy1:  
public static void log(String sMsg) mqiCn]8G  
{ 2HDWlUTNVO  
System.err.println(sMsg); ra1_XR}  
} )ZfbM|  
=r~ExW}+  
[`1@`5SL-  
public static void log(int sMsg) = @lM*  
{ VrJf g  
System.err.println(sMsg); VzWH9%w  
} Z5"5Ge-M  
} 9]g`VD6<v  
nMBF/75  
",S146Y+  
/* 4^ZbT  
**TestMethod.java D+Z2y1
  
*/ zTw<9Nf  
package NetFox; h<g2aL21?F  
"?'9\<>  
SjvSnb_3  
public class TestMethod { -CTLQyj)  
[u^~ND'  
Bsj^R\  
public TestMethod() )vGxF}I3  
{ ///xx/weblogic60b2_win.exe Lv>OBHD  
try{ 4!-/m7%eF  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); j$P`/-N  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 4UMOC_  
SiteFileFetch fileFetch = new SiteFileFetch(bean); zw0u|q;#  
fileFetch.start();
, Q
)  
} r>6FJ:Tx  
catch(Exception e){e.printStackTrace ();} 7Liy
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CxrsP.  
*b"aJ<+  
} m1RjD$fM
 
m~gcc  
/#[mV(k  
public static void main(String[] args) !^Q4ZL,-  
{ jPs{Mr<  
new TestMethod(); =0>[-:Z  
} n9V8A[QJ  
} 'N\nJz}  
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