http断点续传简单实现（java)

/* PX3  
**SiteFileFetch.java Z%v6xP.  
*/ A'"-m)1P  
package NetFox; T#iU+)-\%  
import java.io.*; }#b %"I0  
import java.net.*; MtG_9-  
LC'2q*:'  
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public class SiteFileFetch extends Thread { _IYY08&(r  
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SiteInfoBean siteInfoBean = null; //文件信息Bean -fux2?8M  
long[] nStartPos; //开始位置 /
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long[] nEndPos; //结束位置 H%Y%fQ~^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 PqhlXqX9  
long nFileLength; //文件长度 5V|tXsy:  
boolean bFirst = true; //是否第一次取文件 *:QXz<_x+  
boolean bStop = false; //停止标志 g
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File tmpFile; //文件下载的临时信息 yH(V&Tv  
DataOutputStream output; //输出到文件的输出流 #K`B<2+T  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） fSV5  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3zb)"\(R  
{ z^~U]S3  
siteInfoBean = bean; R]=SWE}U  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); FT_k
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); lS3 _Ild  
if(tmpFile.exists ()) p#M!S2&z  
{ K.h]JD]o  
bFirst = false; #KJZR{  
read_nPos(); ;qT5faKB3J  
} 3*\8p6G  
else O<a3DyUa;  
{ *eoq=,O  
nStartPos = new long[bean.getNSplitter()]; -wIM0YJ  
nEndPos = new long[bean.getNSplitter()]; F`D9Zfd  
} W^ClHQ"Iy  
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} *cy.*@d  
T]X{@_  
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public void run() \#_@qHAG  
{ Znq(R8BMW  
//获得文件长度 Q^q=!/qQ  
//分割文件 I tgH>L'  
//实例FileSplitterFetch |3|wdzV  
//启动FileSplitterFetch线程 (
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//等待子线程返回 6DO0zNTY  
try{ zCM^r <Kr  
if(bFirst) ^s.oZj q  
{ &{hc   
nFileLength = getFileSize(); I &cX8Tw  
if(nFileLength == -1) TwwIt5_fN  
{ ;HT0w_,  
System.err.println("File Length is not known!"); ;_wMWl0F  
} PgqECd)f  
else if(nFileLength == -2) HWOek"}Z[  
{ yvS^2+jW  
System.err.println("File is not access!"); 78^Y;2 P]W  
} >5df@_'  
else I@+lFG  
{ F1/6&u9I  
for(int i=0;i<nStartPos.length;i++) frk7^5  
{ 6O%=G3I
 
nStartPos = (long)(i*(nFileLength/nStartPos.length)); }1@n(#|c  
} %pd5w~VP  
for(int i=0;i<nEndPos.length-1;i++) _82<|NN:  
{ }[ 7Nb90v  
nEndPos = nStartPos[i+1]; [3GKPX:OA/  
} $To4dJb  
nEndPos[nEndPos.length-1] = nFileLength; 1k0^6gE|  
} |F3vRt@  
} EP/&m|o|G  
Xk 5oybDI  
T27:"LVw  
//启动子线程 S|s3}]g9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 1g+LF[*-~  
for(int i=0;i<nStartPos.length;i++) 5X0_+DdeL  
{ NEZH<#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), v4X_v!CQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ]w5ji  
nStartPos,nEndPos,i); nm<L&11  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &f$a1#O}dx  
fileSplitterFetch.start(); LqM
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} L;L2j&i%v)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +k#mvPq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9)1P+c--  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", p!. /  
nEndPos = " + nFileLength); E `?S!*jm  
// fileSplitterFetch[nPos.length-1].start(); &3!i@2d;3f  
 gvvFU,2  
 pb,{$A  
//等待子线程结束 ke{DFqh  
//int count = 0; $%lHj+(  
//是否结束while循环 VGq{y{(  
boolean breakWhile = false; d#x8O4S%i2  
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&Z;Eu'ia  
while(!bStop) Pcdi  
{ 7Y|Wy Oq  
write_nPos(); (gs`=H*d;  
Utility.sleep(500); s|Imz<IE  
breakWhile = true; Lh8#I&x  
#c8"  
;,[EJR^CI  
for(int i=0;i<nStartPos.length;i++) q>Dr)x)  
{ Udb0&Y1^  
if(!fileSplitterFetch.bDownOver) N^nDWK  
{ {&6l\|  
breakWhile = false; ee__3>H"/  
break; 7`j|tb-  
}
+bt
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} *X"F:7  
if(breakWhile) 1tuator  
break; /i7>&ND.r  
#,Fx@3y\a  
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//count++; )
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//if(count>4) zmrX%!CW  
// siteStop(); 'Gm!Jblo@  
} ~a0d.dU  
1{Sx V  
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System.err.println("文件下载结束！"); -v/?>  
} Hf`&&  
catch(Exception e){e.printStackTrace ();} Rwi5+;N  
} ~h~r]tV*+  
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//获得文件长度 .5$V7t.t$\  
public long getFileSize() {Bw
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{ eN7yjd'Y6  
int nFileLength = -1; f{oxF?|89  
try{ )gm\e?^
 
URL url = new URL(siteInfoBean.getSSiteURL()); ~"hAb2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0[3tW[j  
httpConnection.setRequestProperty("User-Agent","NetFox"); Sd/d [  
hKH Q!`&v  
GO&RR}  
int responseCode=httpConnection.getResponseCode(); tL 9e~>,`  
if(responseCode>=400) r>D[5B  
{ \&|w;  
processErrorCode(responseCode); .(.G`aKnF  
return -2; //-2 represent access is error  4
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} 374_G?t&  
34&$_0zn  
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String sHeader; RdpQJ)3F  
(Nve5  
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for(int i=1;;i++) Wg3WE1V  
{ I.n{ "=$B@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); trNK9@wT)  
//Utility.log(in.readLine()); aWi]
t'_  
sHeader=httpConnection.getHeaderFieldKey(i); \c`r9H^v{  
if(sHeader!=null) F$pd]F!#  
{ -V)5Tr=  
if(sHeader.equals("Content-Length")) eWt>^]H~  
{ 0yEyt7 ~@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); mZ.6Njb  
break; & ;x1Rx  
} K,T]Fuy  
} T;vPR,]rz  
else ?.'oxW   
break; LZ<(:S  
} `oI/;&  
} #esu@kMU`  
catch(IOException e){e.printStackTrace ();} H@bm
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catch(Exception e){e.printStackTrace ();} )#TJw@dNf^  
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Utility.log(nFileLength); %)@(Tye -  
3lEU$)QA3  
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return nFileLength; }u$aPS<$!  
} ${H&Q*  
a5g{.:NfO  
XhkL))FcG  
//保存下载信息（文件指针位置） aLo>Yi  
private void write_nPos() |
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{ |gxB; GG  
try{ D&lXi~Z%.  
output = new DataOutputStream(new FileOutputStream(tmpFile)); <'yC:HeAwD  
output.writeInt(nStartPos.length); BY2txLLB  
for(int i=0;i<nStartPos.length;i++) z Clm'X/  
{ YuW\GSV00  
// output.writeLong(nPos); E MbI\=>yS  
output.writeLong(fileSplitterFetch.nStartPos); -2~yc2:>A  
output.writeLong(fileSplitterFetch.nEndPos); N=q29JU  
} zEL[%(fnc  
output.close(); 4'e8VI0  
} tQ<2K*3]  
catch(IOException e){e.printStackTrace ();} vX)Y%I  
catch(Exception e){e.printStackTrace ();} V0&QEul  
} S6:gow(wU  
d-2I_ )9  
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//读取保存的下载信息（文件指针位置） ZuV  
private void read_nPos() s,q!(\{Pv  
{ 545xs`Q_  
try{ F?4'>ZW  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); eEFT(e5.>3  
int nCount = input.readInt(); yc}t(*A5  
nStartPos = new long[nCount]; *wx^mB9  
nEndPos = new long[nCount]; nUu|}11(  
for(int i=0;i<nStartPos.length;i++) yUlQPrNX  
{ akoKx)(<  
nStartPos = input.readLong(); C#c
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nEndPos = input.readLong(); (G;*B<|A  
} `-\JjMSQ1  
input.close(); +\m!#CSA  
} 9~af\G  
catch(IOException e){e.printStackTrace ();} $h f\ #'J  
catch(Exception e){e.printStackTrace ();} ~1!kU4  
} ~hX'FV  
2}#PDhn  
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private void processErrorCode(int nErrorCode) 0pz X!f1~  
{ . 2Q/D?a  
System.err.println("Error Code : " + nErrorCode); 
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} 3xY]Lqwv  
(9%%^s]uPT  
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//停止文件下载 o%7yhCY  
public void siteStop() XcneH jpR  
{ ] lTfi0}g_  
bStop = true; \`x'g)z(i  
for(int i=0;i<nStartPos.length;i++) r}bKVne  
fileSplitterFetch.splitterStop(); ;c}];ZU3G  
k$/].P*!  
8tk`1E8!j  
} C I0^eaFs  
} p^!p7B`qe.  
//负责部分文件的抓取 WDR!e2G  
**FileSplitterFetch.java gd*?kXpt   
*/ X'<xw  
package NetFox; }% *g\%L  
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,vj^AXU  
import java.io.*; 1g+<`1=KT  
import java.net.*; \8ZNXCP  
}z#8vE;  
WDq3K/7\  
public class FileSplitterFetch extends Thread { We2=|AB  
*yx:nwmo  
+Gko[<  
String sURL; //File URL 2NM}u\%c/  
long nStartPos; //File Snippet Start Position B=7L+6  
long nEndPos; //File Snippet End Position nYHk~<a  
int nThreadID; //Thread's ID ]Az >W*Y  
boolean bDownOver = false; //Downing is over x,
+zw9  
boolean bStop = false; //Stop identical ~JJv 2  
FileAccessI fileAccessI = null; //File Access interface  <_~`)t  
dj#<,e\  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Jx]`!dP3  
{ G(>a LF  
this.sURL = sURL; 827N?pU$)  
this.nStartPos = nStart; R0>L[1o  
this.nEndPos = nEnd; uB BE!w_  
nThreadID = id; WG,{:|!E  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 <Ip}uy[Y  
} @({65gJ*  
c!c!;(  
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public void run() y=CemJ[
~  
{ ;rX4${h  
while(nStartPos < nEndPos && !bStop) F9hCT)  
{ <m!\Ma  
+q1@,LxN  
UX6-{ RP  
try{ KM6r}CDHs  
URL url = new URL(sURL); C..O_Zn{g  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &\A$Rj)  
httpConnection.setRequestProperty("User-Agent","NetFox"); \6o ~ i  
String sProperty = "bytes="+nStartPos+"-"; &wJ"9pQ~6E  
httpConnection.setRequestProperty("RANGE",sProperty); IzG7!K  
Utility.log(sProperty); rei<{woX  
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n`6vM4rM)  
InputStream input = httpConnection.getInputStream(); W!{uEH{%l  
//logResponseHead(httpConnection); qVf~\H@  
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byte[] b = new byte[1024]; iS"rMgq  
int nRead; >o@WT kF]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2a{eJ89f  
{ +m"iJW0  
nStartPos += fileAccessI.write(b,0,nRead); "*UHit;"+{  
//if(nThreadID == 1) ?wmr~j  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  `=oN&!  
} SQ@@79A  
JI.ad_IR
 
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Utility.log("Thread " + nThreadID + " is over!"); &.d~ M
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bDownOver = true; .; :[sv)  
//nPos = fileAccessI.write (b,0,nRead); [Ga9^e$Zv  
} mFT[[Z#  
catch(Exception e){e.printStackTrace ();} DJ
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} ]R0^ }sI  
} (HY|0Bgr  
yHCBf)N7\  
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//打印回应的头信息 tvI~?\Ylj  
public void logResponseHead(HttpURLConnection con) 4rv3D@E  
{ o#G7gzw)  
for(int i=1;;i++) F`'e/  
{ 8%Pjx7'<  
String header=con.getHeaderFieldKey(i); #qHo+M$"  
if(header!=null) X|X6^}  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &AC-?R|Dp  
Utility.log(header+" : "+con.getHeaderField(header)); 7|\[ipVX:3  
else <vOljo  
break; s(F^P  
} r'-)@|  
} R|`}z"4C  
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public void splitterStop() WC0@g5;1[  
{ ,0;E_i7  
bStop = true; Qr$uFh/y  
} }Z"<KF  
%=%jy  
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} DtR-NzjB  
DM"`If%3j  
Jy{A1i@4~s  
/* CZt)Q4  
**FileAccess.java yD(0:g#  
*//文件访问(定位，写) e$fxC-sZ  
package NetFox; yD$rls:v<  
import java.io.*; USfOc  
Y<I/y  
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public class FileAccessI implements Serializable{ =&< s*-l[  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 pu=Q;E_f[  
RandomAccessFile oSavedFile; gs7H
9%j{U  
long nPos; 5,|^4 ZA  
9co1+y=i{  
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public FileAccessI() throws IOException \&n]W\  
{ 8!'#B^  
this("",0); ~W_m<#K(  
} ;a[56W  
!i2=zlpb[  
y/
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public FileAccessI(String sName,long nPos) throws IOException 7_?:R2]n  
{ [}N?'foLb  
oSavedFile = new RandomAccessFile(sName,"rw");
Ul)2A  
this.nPos = nPos; [j`It4^nC  
oSavedFile.seek(nPos); O sbY}*S  
} {|O8)bW'  
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GTyS8`5E*  
public synchronized int write(byte[] b,int nStart,int nLen) T4F}MVK  
{ ^8a,gA
8.  
int n = -1; ![18+Q\  
try{ P*BA  
oSavedFile.write(b,nStart,nLen); '(7]jug  
n = nLen; x}?y@.sn8  
} kS%FV;9>(  
catch(IOException e) @(,k%84z  
{ ;oH17  
e.printStackTrace (); {Nuwz|Ci  
} *RD9gIze  
wm}6$n?Za  
FVPhk2  
return n; xa[<k>r3  
} !k)}p_e  
5?&k? v@  
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} cZuZfM
DM  
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@F]6[  
/* <UQaRI[55  
**SiteInfoBean.java iW(HOsA  
*/ fIu5d6;'  
package NetFox; 3k`"%R.H  
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Z3<>Z\6D  
public class SiteInfoBean { &^Zo}F2V  
8p,q9Ey  
s^TF+d?B  
private String sSiteURL; //Site's URL #oSQWC=T  
private String sFilePath; //Saved File's Path OmQSNU.our  
private String sFileName; //Saved File's Name H$>D_WeJ  
private int nSplitter; //Count of Splited Downloading File ({zt=}r,  
p+SFeUp  
 kj~)#KDN  
public SiteInfoBean() "^u  
{//nSplitter的缺省值为5 j#S>8: G  
//default value of nSplitter is 5 B q+RFo  
this("","","",5); 7h?PVobe  
} y44FejH(v  
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=unMgX]$  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 1k6f|Al-  
{ nud,ag  
sSiteURL= sURL; VI,z7 \  
sFilePath = sPath; y:WRpCZoa  
sFileName = sName; AR\>P   
this.nSplitter = nSpiltter; &Y%Kr`.h  
M8
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3Q*K+(`{  
} WCA`34(  
8+{WH/}y8  
M7^PWC  
public String getSSiteURL() [7q~rcf,Z  
{ WY_}D!O  
return sSiteURL; 9a9<I  
} >gM|:FG  
ny%-u&1k  
FiMP_ y*S  
public void setSSiteURL(String value) &>\E >mJ  
{ kD dY i7g>  
sSiteURL = value; 3.U5Each-  
} }WS%
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3GUO  
htk5\^(X  
public String getSFilePath() 9#{?*c6  
{ &1YAPxX  
return sFilePath; RKFj6u  
} Pwf2dm$,+  
7].
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_?#}@?  
public void setSFilePath(String value) YqX/7b+  
{ XFeHkU`C  
sFilePath = value; KGdL1~  
} ,pE{N&p9  
zm4Okg)w@  
^]o]'  
public String getSFileName() -1d2Qed  
{ e#JJd=  
return sFileName; EL$l . v  
} Uq `B#JI  
}+G6`Zd  
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}  
public void setSFileName(String value) G/>upnA{w  
{ KZUB{
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sFileName = value; \&ra&3o  
} e84[B.  
U1G"T(;s:  
bDVz+*bU}  
public int getNSplitter() \E1[ /  
{ +pp|Qgr 3  
return nSplitter; wZ/Zc} .  
} dPgN*Bdv  
)w_0lm'v{r  
*>,8+S33r{  
public void setNSplitter(int nCount) ,<s'/8Ik  
{ p9rnhqH6  
nSplitter = nCount; ce-5XqzY@  
} `K37&b;`[  
} 8gWifx #N  
'1{co/Y  
SVWtKc<  
/* H!mNHY_fA  
**Utility.java 2iC7c6hc  
*/ KR4X&d6  
package NetFox; Lpd q^X  
hbdq'2!Qr  
|pxM8g1w  
public class Utility { ?CIMez(h  
Hh`x>{,|S  
78&(>8@m  
public Utility() a[d6@!  
{ k)j,~JH  
$?RxmWsP  
`%_yRJd|;  
} +EG?8L,z  
|^p7:)cy  
//线程睡眠 W(U:D?e  
public static void sleep(int nSecond) NT+%u-  
{ 5%M '
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try{ 1}nrVn[B9  
Thread.sleep(nSecond); "cSH[/  
} kU^*hd]  
catch(Exception e) }jTCzqHW]  
{ 1KwUp0%&  
e.printStackTrace (); 40,u(4.m*  
} d7
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} ;s{k32e  
}4G/x;D  
//日志 \yDr  
public static void log(String sMsg) =(\ /+ 0-[  
{ $OEhdz&Fi  
System.err.println(sMsg); $M%<i~VXe&  
} qQ\&]  
4rkj$  
>a;0<Ui&Q  
public static void log(int sMsg) ,m ^q>  
{ ^f][;>c  
System.err.println(sMsg); sXe=4`O  
} +M@p)pyu  
} ErZYPl  
2^Y@e=^A  
P]V/<8o.53  
/* ,EhQTVJ  
**TestMethod.java $TU)O^c  
*/ Z*r;"WHB  
package NetFox;
|S0]qt?  
& !0[T   
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public class TestMethod { 79}voDFd  
lJZ-*"9V  
W>jgsR79M  
public TestMethod() B_Qi  
{ ///xx/weblogic60b2_win.exe +-8u09-F  
try{ o0SQJ1.a$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); IC5[:UZ5]
 
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [Ol}GvzJ7  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *c"tW8uR  
fileFetch.start();  -w7g}  
} Y<1]{4Wt  
catch(Exception e){e.printStackTrace ();} HI+87f_Q  
gie.K1@|  
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} |n9q4*dN  
G3 h&nH,>  
6:PQkr  
public static void main(String[] args) Ed&;d+NM  
{ p~X=<JM  
new TestMethod(); D)0pm?*5A  
} 'ju  
} L H>oG$a  
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