http断点续传简单实现（java)

/* r&ex<(I{  
**SiteFileFetch.java }mw31=2bD  
*/ 3AD^B\<gB  
package NetFox; tpi63<N  
import java.io.*; "n@=.
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import java.net.*; iPJZ%  
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public class SiteFileFetch extends Thread { fKAG+t  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Lw.N3!e[  
long[] nStartPos; //开始位置 '4qi^$|\  
long[] nEndPos; //结束位置 E8Wgm 8  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )f0t"l
k  
long nFileLength; //文件长度 !Hr +|HKQ?  
boolean bFirst = true; //是否第一次取文件 -3c?Yaf"  
boolean bStop = false; //停止标志 5fBW#6N/  
File tmpFile; //文件下载的临时信息 z|SLH<~  
DataOutputStream output; //输出到文件的输出流 R3$
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2$? )
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） +x0-hRD  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]E)gMf   
{ 2FS,B\d  
siteInfoBean = bean; ;wz YZ5=Di  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); l$Y7CIH  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %-:6#bz  
if(tmpFile.exists ()) l>M&S^/s j  
{ @Tr8.4  
bFirst = false; ZUMzWK5Th  
read_nPos(); T{j&w%(z  
} _>*$%R  
else #sEbu^  
{ LE!3'^Zq  
nStartPos = new long[bean.getNSplitter()]; i5*sG^<$H  
nEndPos = new long[bean.getNSplitter()]; @hWt.qO3s  
} {j E}mzi  
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} Ydu=Jg5u7  
*,o)`  
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public void run() ]#[R^t  
{ 6?ylSQ]1  
//获得文件长度 m`-{ V<(M  
//分割文件 d7tH~9GX8  
//实例FileSplitterFetch H6*d#!  
//启动FileSplitterFetch线程 C sn"sf  
//等待子线程返回 I/MYS5}
 
try{ K$\]\qG6  
if(bFirst) VHB5
 
{ pXCmyLQ  
nFileLength = getFileSize(); jzu1>*ok  
if(nFileLength == -1) ?!~CX`eMZ  
{ ueYZM<],  
System.err.println("File Length is not known!"); t*^Q`V wQ  
} +B
%ZB9  
else if(nFileLength == -2) [*#ms=Zdc  
{ aBT|Q@Y.  
System.err.println("File is not access!"); -2mm 5E~N  
} QE$sXP7&u  
else Ry0n_J:7  
{ zrG&p Z  
for(int i=0;i<nStartPos.length;i++) H{`S/>)[   
{ m>?OjA!  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5+'1 :Sa(i  
} Rg,pC.7;  
for(int i=0;i<nEndPos.length-1;i++) qv=i eU  
{ "wTA9\  
nEndPos = nStartPos[i+1]; $v+Q~\'  
} L*1C2EL/q  
nEndPos[nEndPos.length-1] = nFileLength; `(EY/EsY  
}  &jf:7y  
} ~k4S~!(U0  
Y:/z)"u,C  
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//启动子线程 zN {'@B  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; gz-}nCSi  
for(int i=0;i<nStartPos.length;i++) < ppg$;  
{ >c?Z.of  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +EJIYvkFm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), y'pAhdF  
nStartPos,nEndPos,i); vWcU+GBZI  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); TB4|dj-%  
fileSplitterFetch.start(); `TOm.YZG  
} @%fNB,H`
 
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), gyJ$Jp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &mKtW$K` q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Q\Fgc ;.U  
nEndPos = " + nFileLength); \;}F6g  
// fileSplitterFetch[nPos.length-1].start(); [&y{z-D>  
o4,W!^n2  
:03w k)  
//等待子线程结束 ^N _kiSr  
//int count = 0; noC]&4b  
//是否结束while循环 E=3<F_3W  
boolean breakWhile = false; ,[%KSyH  
|#Bz&T  
M;,Q8z%  
while(!bStop) ]i)m   
{ (u+3{Eb  
write_nPos(); 5vxJ|Hse@  
Utility.sleep(500); Oj6-  
breakWhile = true; YgCJ s;  
x-+Hy\^@|  
1RZhy_$\.  
for(int i=0;i<nStartPos.length;i++) %vDN{%h8  
{ aRdzXq#x  
if(!fileSplitterFetch.bDownOver) f+j\,LJ  
{ &aqF||v%)  
breakWhile = false; K 38e,O  
break; )'KkO$^&  
} iVLfAN @  
} 0~Z>}(  
if(breakWhile) &p%0cjg"Q  
break; yf*^Y74  
hW6og)x  
,8nu%zcVn  
//count++; |?hNl2m  
//if(count>4) u;GS[E4  
// siteStop(); i<l_z&  
} V<Q''%k  
LWuciHfd+  
Ly0^ L-~|  
System.err.println("文件下载结束！"); ) RS*MEgA  
} k*d0ws#<l  
catch(Exception e){e.printStackTrace ();} @k>}h\w  
} %{WS7(si  
Pk!RgoWF  
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//获得文件长度 [QEV6S]  
public long getFileSize() F~2bCy[Z  
{ ) gbns'Z<  
int nFileLength = -1; z^j7wMQ  
try{ _8Cw_  
URL url = new URL(siteInfoBean.getSSiteURL()); z'Atw"kA  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t<wjS|4  
httpConnection.setRequestProperty("User-Agent","NetFox"); I !=ew |  
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int responseCode=httpConnection.getResponseCode(); bfcQ(m5  
if(responseCode>=400) N"1o> !  
{ y_boJ  
processErrorCode(responseCode); Jw3VWc ]]  
return -2; //-2 represent access is error UKV0xl  
} m r"b/oM{  
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String sHeader; {Z0(V"Q  
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for(int i=1;;i++) ^)oBa=jL4  
{ Cp4 U`]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ix2V?\  
//Utility.log(in.readLine()); *;cvG?V  
sHeader=httpConnection.getHeaderFieldKey(i); :}'5'oVG  
if(sHeader!=null) @6\Id7`Ea  
{ KT$Za
  
if(sHeader.equals("Content-Length")) /9T.]H~  
{ ,Ta k',  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); B;x5os  
break; ybNo`:8A;  
} WxLbf+0o  
} Od_xH
 
else ""$vaqt  
break; oGt,^!V1  
} 1T&NU  
} \PReQ|[ah  
catch(IOException e){e.printStackTrace ();} {Tx"G9  
catch(Exception e){e.printStackTrace ();} 'u@,,FFz[K  
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yp}J+/PX}  
Utility.log(nFileLength); QS7<7+  
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return nFileLength; J5dwd,FQ  
} skrdL.5  
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//保存下载信息（文件指针位置） (;\" K?  
private void write_nPos() [$\KS_,Mn  
{ #+CH0Z  
try{ sgYPR  
output = new DataOutputStream(new FileOutputStream(tmpFile)); s
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output.writeInt(nStartPos.length); Uh[MBwK  
for(int i=0;i<nStartPos.length;i++) tb$I8T  
{ XZ%3PMq  
// output.writeLong(nPos); nA owFdCD  
output.writeLong(fileSplitterFetch.nStartPos); g0({$2Q7R  
output.writeLong(fileSplitterFetch.nEndPos); ;wGoEN  
} #aI(fQZe  
output.close(); rhff8C//'  
} xER-TT#S  
catch(IOException e){e.printStackTrace ();} |"]#jx*8KC  
catch(Exception e){e.printStackTrace ();} an q1zH  
} 9w3KAca  
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//读取保存的下载信息（文件指针位置） BD.&K_AW  
private void read_nPos() arK(dg~S  
{ UHyGW$B  
try{ qa-%j+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); &t)$5\r  
int nCount = input.readInt(); jVlXB6[-  
nStartPos = new long[nCount]; &{4KymB:  
nEndPos = new long[nCount]; >]{{5oOQ>  
for(int i=0;i<nStartPos.length;i++) /]U),Lb
N  
{ {L'uuG\9U  
nStartPos = input.readLong(); 3~q#P  
nEndPos = input.readLong(); /1@py
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} !NqLBrcv0  
input.close(); cr,fyAvX  
} Qg6tJ
B   
catch(IOException e){e.printStackTrace ();} &/m0N\n?  
catch(Exception e){e.printStackTrace ();} "+XF'ZO  
} kz0pX-@b  
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private void processErrorCode(int nErrorCode) g"{`g6(+  
{ mzO5&h7  
System.err.println("Error Code : " + nErrorCode); @`mr|-Rp@  
} J]W? Vvv  
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_  
//停止文件下载 Y{KN:|i.!  
public void siteStop() QLxe1[qI  
{ *""iX
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bStop = true; hKVb#|$  
for(int i=0;i<nStartPos.length;i++) Cl6P,C  
fileSplitterFetch.splitterStop(); `y
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} C5,\DdCX,  
} HXm
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//负责部分文件的抓取 _|r/*(hh  
**FileSplitterFetch.java "]T1DG"  
*/ a#D \8;  
package NetFox;  sWyx_  
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import java.io.*; 0VnRtLnqI  
import java.net.*; ZAJ~Tbm[f  
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public class FileSplitterFetch extends Thread { :]icW^%  
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String sURL; //File URL 7aS%;EU  
long nStartPos; //File Snippet Start Position Xv+!)j<  
long nEndPos; //File Snippet End Position QVF561Yz  
int nThreadID; //Thread's ID yi8AzUW cW  
boolean bDownOver = false; //Downing is over A(9$!%#+L  
boolean bStop = false; //Stop identical /&Hl62Ak  
FileAccessI fileAccessI = null; //File Access interface Py`7)S
 
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException o)wOXF  
{ }0Q T5  
this.sURL = sURL; |J"\~%8  
this.nStartPos = nStart; B='(0Uxy-  
this.nEndPos = nEnd; rR4?*90vjj  
nThreadID = id; ?7#{#sj  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Xz?7x0)Z  
} !q~f;&rg  
fh*7VuAc  
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public void run() "#:h#uRUb  
{ ~tLvD[n[  
while(nStartPos < nEndPos && !bStop) x"7PnN|~  
{ !
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n5 <B*  
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try{ 4d_Az'7`4  
URL url = new URL(sURL); Sim$:5
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); R2==<"gq  
httpConnection.setRequestProperty("User-Agent","NetFox"); dy~M5,zn  
String sProperty = "bytes="+nStartPos+"-"; q>s`G  
httpConnection.setRequestProperty("RANGE",sProperty); >}bkX 6c5  
Utility.log(sProperty); (&=3Y8  
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i# fvF)  
InputStream input = httpConnection.getInputStream(); bN&DotG  
//logResponseHead(httpConnection); :*vSC:q  
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[x%8l,O #l  
byte[] b = new byte[1024]; ]|N"jr?7H  
int nRead; RA!8AS?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) (Z0.H3  
{ KGf@d*ZOMz  
nStartPos += fileAccessI.write(b,0,nRead); k$.l^H u  
//if(nThreadID == 1) og1Cj{0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
L'$({  
} 8PqlbLo1  
&k`/jl;u  
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Utility.log("Thread " + nThreadID + " is over!"); cpPS8V  
bDownOver = true; m2l0`l~T8  
//nPos = fileAccessI.write (b,0,nRead); 9&HaEAme  
} "u'dd3!  
catch(Exception e){e.printStackTrace ();} _7R6%^  
} S"fqE%  
} R2qz>kyyB  
#'m#Q6`  
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//打印回应的头信息
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public void logResponseHead(HttpURLConnection con) A9WOu*G1O  
{ &?I3xzvK  
for(int i=1;;i++) BwYR"  
{ H? %I((+  
String header=con.getHeaderFieldKey(i); bo??91B^7  
if(header!=null) "HLh3L~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 5>:p'zI  
Utility.log(header+" : "+con.getHeaderField(header)); Va4AE)[/*  
else -j^G4J  
break; _QtW)\)5\  
} o9v.]tb  
} wuhL r(  
{)4@rM  
+3pfBE|  
public void splitterStop() MnQ 6 !1Z  
{ k#2b3}(,  
bStop = true; H:t2;Z'  
} t4p-pH'9b  
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} >`n)-8  
9?|m ^  
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/* q#0yu"<  
**FileAccess.java pW&8 =Ew  
*//文件访问(定位，写) vX*kvEG  
package NetFox; C?rb}(m  
import java.io.*; ']sIU;h3  
ZV!*ZpTe~  
0 d2to5 (  
public class FileAccessI implements Serializable{ "9RW<+  
Zf?jnDA  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 '1lz`CAB+  
RandomAccessFile oSavedFile; /pp;3JPf  
long nPos; R;w1& Z  
s="cg0PD  
j[w5#]&%  
public FileAccessI() throws IOException nB |fw"
 
{ WhL"-f  
this("",0); jYh.$g<`0+  
} .Zx7+`i  
!)OA7%3m  
i,/Q.XL  
public FileAccessI(String sName,long nPos) throws IOException 2yV{y#\  
{ V
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oSavedFile = new RandomAccessFile(sName,"rw"); UQ2;Dg G%  
this.nPos = nPos; mW."lzIl  
oSavedFile.seek(nPos); \U?{m)N  
} HmpV; <t3  
(Jy >,~O  
*%dWNvN4X  
public synchronized int write(byte[] b,int nStart,int nLen) }& 01=nY  
{ Z?'?+48xv4  
int n = -1; Wp=:|J  
try{ 0urM@/j+  
oSavedFile.write(b,nStart,nLen); P'k`H  
n = nLen; +B O
uU#  
} Z15b'^)?9  
catch(IOException e) 4hV~ ir  
{ i^/D_L.  
e.printStackTrace (); zQx7qx  
} WtbOm  
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return n; I\VC2U  
} T(bFn?  
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} (a8oI)~  
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{qBbzBG  
/* o(5 (]bJ  
**SiteInfoBean.java mvBUm-X  
*/ H{*R(S<I  
package NetFox; ;gW?Fnry;  
nB ,&m&  
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public class SiteInfoBean { 9/50+2F  
 TGozoPV  
@RS|}M^4  
private String sSiteURL; //Site's URL CA ,0Fe3  
private String sFilePath; //Saved File's Path J_ `\}55n  
private String sFileName; //Saved File's Name B ? D|B  
private int nSplitter; //Count of Splited Downloading File t/:]\|]WB  
51x)fZQ  
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public SiteInfoBean() !CuLXuM  
{//nSplitter的缺省值为5 W_G'wU
3R  
//default value of nSplitter is 5 5I@2UvV8  
this("","","",5); RLbxNn  
} $.r:  
.cm$*>LW:x  
v]BMET[w  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) )WazbT@  
{ XDq*nA8#5B  
sSiteURL= sURL; l050n9#9p  
sFilePath = sPath; $Z^HI  
sFileName = sName; . vQCX1V(  
this.nSplitter = nSpiltter; S%m$LM]NCg  
(SYSw%
v$A  
s:#\U!>0`  
} Sf*b{6lcC  
Mi_/ ^  
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public String getSSiteURL() Sj<WiQ%<  
{ m%km@G$  
return sSiteURL; {QTnVS't 0  
} V3$Yr"rZ;  
9;u&,R  
/__@a&9t  
public void setSSiteURL(String value) <;Bv6.Z  
{ k),.  
sSiteURL = value; (-U6woB6o  
} T#e ;$\  
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public String getSFilePath() <)\  
{ wR=WS',  
return sFilePath; 11(:#4Y,  
} 8%wu:;*]%  
/2e&fxxD  
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public void setSFilePath(String value) 9vZD?6D,n  
{ Q-}
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sFilePath = value; {"uLV{d  
} Q5H! ^RQm  
iFy_D  
/!mF,oR!  
public String getSFileName() CQx#Xp>=s  
{ >3a<#s{%  
return sFileName; (}u2) 9  
} ]l WEdf+  
_c4kj  
93*MY7j}  
public void setSFileName(String value) (/r l\I  
{ lU[" ZFP  
sFileName = value; O+^l>+ZGj?  
} Gd8FXk,.!  
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"NgfdLz  
public int getNSplitter() %cl=n!T  
{ j%m9y_rg}  
return nSplitter; `'Af`u\R  
} )E.!jL:g  
rVE!mi]%  
Pn*+g!`  
public void setNSplitter(int nCount) ROyG+dUy  
{ As;@T$G  
nSplitter = nCount; 5QR=$?K  
} U2u\Q1  
} Gb\Nqx(  
Is $I;`  
^T#bla893  
/* #ONad0T;  
**Utility.java .W#
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*/ 5DEK`#*  
package NetFox; 0 xUw}T6  
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public class Utility {
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?W*{%my  
public Utility() N
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{ ke sg]K  
:QGd/JX$n`  
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} V kA$T8  
[!ghI%VK  
//线程睡眠 LK}Ih@f  
public static void sleep(int nSecond) &G)I|mv  
{ ?~vVSY  
try{ 0GtL6M@pP  
Thread.sleep(nSecond); ^}+qd1r  
} iz&$q]P8  
catch(Exception e) avmuI^LLs  
{ S4m??B  
e.printStackTrace (); ,F,\bp}  
} ' DZYN {}  
} ;wi}6rF%[i  
zq=X;}qYj  
//日志 a5/6DK>  
public static void log(String sMsg) b1(7<o  
{ D`?=]Ysz(  
System.err.println(sMsg); J3F-Yl|  
} i|]Kw9  
!\ IgTt,  
QUPZe~G>L  
public static void log(int sMsg) Nq`@ >Ml  
{ eD4qh4|u.  
System.err.println(sMsg); (h}5*u%h  
} Q M#1
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} L9|55z  
Ho}"8YEXNV  
Rr'#OxF  
/* yMU>vr  
**TestMethod.java A{[joo  
*/ NtuO&{}i  
package NetFox; dr|>P*  
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"$-
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public class TestMethod { 3D"2yTM(  
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Rqi=AQ  
public TestMethod() 1G0U}-6RH  
{ ///xx/weblogic60b2_win.exe n9 LTrhLqp  
try{ x)Y?kVw21"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); iP7 Cku}l  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); #JmVq-)  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 9Q~9C9{+  
fileFetch.start(); Mbj{C  
} q#{.8H-X'  
catch(Exception e){e.printStackTrace ();} vD=>AAvG  
mv5=>Xc6  
+VJS/  
} ! :[`>=!  
:bh#,]'  
J**-q(>  
public static void main(String[] args) qc(R /[  
{ C 2f=9n/  
new TestMethod(); qO;.{f  
} aC\O'KcH  
} y /$Q5P+o  
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