http断点续传简单实现（java)

/* ~id6^#&>  
**SiteFileFetch.java r"H::A  
*/ 7Sdo*z  
package NetFox; A U~DbU0O  
import java.io.*; ( eV,f  
import java.net.*; *&U~Io"U  
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*^>" h@J  
public class SiteFileFetch extends Thread { +VwQ=[y]  
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SiteInfoBean siteInfoBean = null; //文件信息Bean K3&xe(  
long[] nStartPos; //开始位置 U}92%W?  
long[] nEndPos; //结束位置 vPkLG*d8  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Z|$#  
long nFileLength; //文件长度 v^"\e&XL  
boolean bFirst = true; //是否第一次取文件 ]#
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boolean bStop = false; //停止标志 +eVYy_bL-  
File tmpFile; //文件下载的临时信息 1tuvJ+`{  
DataOutputStream output; //输出到文件的输出流
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8SRR)O[)}  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） n 0!8)Sth  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5es t  
{ W"\~O"a  
siteInfoBean = bean; 5xH=w:  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "*vrrY  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 6w.E Sm  
if(tmpFile.exists ()) vCa8`
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{ 3%v)!dTa<^  
bFirst = false; *l5?_tF  
read_nPos(); #W\}v(Ke  
} ;i@S}LwL  
else Yf0 
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{ DrRK Sc(u9  
nStartPos = new long[bean.getNSplitter()]; +n^M+ea;  
nEndPos = new long[bean.getNSplitter()]; JCWTB`EB>  
} 0`/G(ukO  
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} b]u$!W  
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C% -Tw]T$_  
public void run() v l"8Oi*r^  
{ GRZz@bAO?$  
//获得文件长度 \`Hp/D1  
//分割文件 ?N kKDvv  
//实例FileSplitterFetch Ny^ 1#R  
//启动FileSplitterFetch线程 !73y(Y%TE  
//等待子线程返回 *g5bdQ:Av~  
try{ &ALnE:F  
if(bFirst) hHJiGVJ=V  
{ 
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nFileLength = getFileSize(); 0O3O^ 0  
if(nFileLength == -1) Q-x>yau"  
{ #XQ/y}(  
System.err.println("File Length is not known!"); gL<n?FG4b  
} qu B[S)2}  
else if(nFileLength == -2) 5 -i,Tx&:  
{ !h?HfpYv  
System.err.println("File is not access!"); ~J\qkQ  
} _8G w Mj  
else 9xA4;)36  
{ Hf4_zd  
for(int i=0;i<nStartPos.length;i++) {Y~>&B5  
{ W3:j Z:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); aoy Be|H~=  
} {4_s:+v0  
for(int i=0;i<nEndPos.length-1;i++) i6Z7
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{ i'fw>-0  
nEndPos = nStartPos[i+1]; M CC4'  
} 3.W[]zH/u  
nEndPos[nEndPos.length-1] = nFileLength; @CNJpQ ujn  
} pg{VKrT`  
} - 2)k!5X=  
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TV{GHB!p"  
//启动子线程 BTAbDyH5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^4=#,K  
for(int i=0;i<nStartPos.length;i++) 7@@g|l]  
{ t/ \S9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^ITF*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 're:_;lG  
nStartPos,nEndPos,i);  L<FXtBJ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  IuY9Q8  
fileSplitterFetch.start(); nDnJ}`k  
} luP;P&  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uV:R3#^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); wra0bS)4  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", k4Q>J,k  
nEndPos = " + nFileLength); HV%/baX]  
// fileSplitterFetch[nPos.length-1].start(); xPZ>vCg  
{aAd (~YZ  
1ksFxpE  
//等待子线程结束 UZ<K'H,q  
//int count = 0; ;JxL>K(  
//是否结束while循环 "_/ih1z]
 
boolean breakWhile = false; HH*y$  
fd[N]I3  
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while(!bStop) Q`F1t  
{ k;\gYb%L  
write_nPos(); \2@J^O1,  
Utility.sleep(500); .wNXvnWr  
breakWhile = true; pU_3Z3CeE  
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for(int i=0;i<nStartPos.length;i++) um%_kX  
{
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if(!fileSplitterFetch.bDownOver) }y6)d.   
{ @43psq1  
breakWhile = false; <,CrE5Pl  
break; U:8[%a  
} t7byOMC  
} "$(+M t^  
if(breakWhile) mx^Ga=: ?  
break; hywcj\[  
=~ Uhr6Q  
I|rb"bG  
//count++; SIp)&  
//if(count>4) #*bmwb*i  
// siteStop(); y#'hOSR2  
} )$]lf }  
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System.err.println("文件下载结束！"); \Th<7WbR6#  
} y,5qY}P+  
catch(Exception e){e.printStackTrace ();} wPg/.N9H  
} /\%<VBx ?q  
rZ?:$],U!  
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//获得文件长度 7^><Vh"qV  
public long getFileSize() 6]v}  
{ ~5,^CTAM  
int nFileLength = -1; MZG
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try{ l5-[a  
URL url = new URL(siteInfoBean.getSSiteURL()); !<M eWo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )JzY%a SP  
httpConnection.setRequestProperty("User-Agent","NetFox"); uzdPA'u  
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int responseCode=httpConnection.getResponseCode(); g-qXS]y7  
if(responseCode>=400) >NUbk9}J4  
{ u%C oo  
processErrorCode(responseCode); f\_RW;y|m  
return -2; //-2 represent access is error c|/HX%Y  
} <UGaIb  
@jn&Wf?  
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String sHeader; BAQ-1kSz  
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for(int i=1;;i++) )9H5'Wh#  
{ dk&e EDvfd  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ny{C,1QG  
//Utility.log(in.readLine()); Om*QN]lGq  
sHeader=httpConnection.getHeaderFieldKey(i); CY o m  
if(sHeader!=null) 7I;kh`H$(f  
{ 8 #4K@nm5  
if(sHeader.equals("Content-Length")) V|u2(*  
{
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); yX!u&  
break; I/7!5
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} brA#p>4]Wf  
} F'XQoZ* 1  
else M">v4f&K1!  
break; jz8u'y[n7  
} cUq]PC$|  
} 8R*;8y_  
catch(IOException e){e.printStackTrace ();} -m@c{&r  
catch(Exception e){e.printStackTrace ();}  Qxz[  
h  /  
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Utility.log(nFileLength);  w*`:v$  
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return nFileLength; tz):$1X_  
} ZeV@ X  
S
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//保存下载信息（文件指针位置） # `=Zc7gf  
private void write_nPos() TipH}  
{ X9| Z?jJ  
try{ `bQ_eRw}  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?("O.<
 
output.writeInt(nStartPos.length); ^$Y9.IH"  
for(int i=0;i<nStartPos.length;i++) =d8Rij-  
{ +0Q   
// output.writeLong(nPos); :^y!z1\2(7  
output.writeLong(fileSplitterFetch.nStartPos); lgews"  
output.writeLong(fileSplitterFetch.nEndPos); WX4sTxJK  
} TOHz3=  
output.close(); >SXSrXyYX  
} k>ErDv
8  
catch(IOException e){e.printStackTrace ();} b/_Zw^DPC  
catch(Exception e){e.printStackTrace ();}
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} \9[vi +T  
m]?Z_*1  
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//读取保存的下载信息（文件指针位置） +;W%v7%<  
private void read_nPos() Gj?Zbl <  
{ =n,;S W  
try{ llZU: bs  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {($bzT7c  
int nCount = input.readInt(); {
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nStartPos = new long[nCount]; ;VLDXvGd  
nEndPos = new long[nCount]; ^/#+0/Bn  
for(int i=0;i<nStartPos.length;i++) 5[;[Te9=S  
{ %gmx47  
nStartPos = input.readLong(); Bj7*2}  
nEndPos = input.readLong(); XH%pV  
} /[TOy2/;%b  
input.close(); UIEvwQ  
} c~U0&V_`j  
catch(IOException e){e.printStackTrace ();} GQt5GOt  
catch(Exception e){e.printStackTrace ();}  ]~;*9`:  
} LtB5;ByeQ0  
?d%)R*3IX  
pwN2Nzski  
private void processErrorCode(int nErrorCode) Yh95W  
{ d.f0OhQ  
System.err.println("Error Code : " + nErrorCode); =b%f@x_U1  
} s:_hsmc"  
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IBNg2Y  
//停止文件下载 GXZ="3W |  
public void siteStop() Qm[((6}  
{ i$y=tJehi  
bStop = true; QD.5o
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for(int i=0;i<nStartPos.length;i++) =OK#5r[UV  
fileSplitterFetch.splitterStop(); k5< n:
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}
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} \ZRII<k5)  
//负责部分文件的抓取 ()6%1zCO  
**FileSplitterFetch.java A'w+Lc.2  
*/ tEL;,1  
package NetFox; L<V20d9
  
b=Nsz$[  
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import java.io.*; oVw4M2!"K  
import java.net.*; 21OfTV-+3  
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public class FileSplitterFetch extends Thread { }!^h2)'7  
W $D 34(  
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String sURL; //File URL SLuQv?R}9  
long nStartPos; //File Snippet Start Position .Vt|;P}  
long nEndPos; //File Snippet End Position K21Xx`XK  
int nThreadID; //Thread's ID 1le9YL1_g  
boolean bDownOver = false; //Downing is over ;,-)Z|W  
boolean bStop = false; //Stop identical |Kd6.Mx  
FileAccessI fileAccessI = null; //File Access interface @ fMlbJq  
vE9"1M  
b#I,Z+0ry  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException '\{ OQH  
{ 6Y[&1c8  
this.sURL = sURL; s>;"bzzq  
this.nStartPos = nStart; oRd{?I&NY  
this.nEndPos = nEnd; >*!T`P}p  
nThreadID = id; @Xoh@:j\  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~jw:4sG  
} No\#N/1@P  
*4~7p4[  
)%jS9e{d  
public void run() L\ysy2E0  
{ q[/g3D\G  
while(nStartPos < nEndPos && !bStop) _dd_Z40R  
{ KdR\a&[MA  
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try{ ]}SV%*{%  
URL url = new URL(sURL); R{}_Qb  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !& c%!*  
httpConnection.setRequestProperty("User-Agent","NetFox"); > X AB#  
String sProperty = "bytes="+nStartPos+"-"; (NUX
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httpConnection.setRequestProperty("RANGE",sProperty); f]1 $`  
Utility.log(sProperty); >kAJS??  
1%M^MT%&  
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InputStream input = httpConnection.getInputStream(); IO#)r[JZ  
//logResponseHead(httpConnection); {$N\@q@v~  
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byte[] b = new byte[1024]; JK)|a@BtOT  
int nRead; j 1'H|4  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) NHZMH!=4:n  
{ crd|r."
 
nStartPos += fileAccessI.write(b,0,nRead); yYOV:3!"  
//if(nThreadID == 1) 6AD&%v  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); VFV8ik)  
} w8o?wx*  
I-.?qcy~  
VII`qbxT  
Utility.log("Thread " + nThreadID + " is over!"); P
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bDownOver = true;  qjfv9sU  
//nPos = fileAccessI.write (b,0,nRead); ^ &KH|qRrO  
} h<m>S
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catch(Exception e){e.printStackTrace ();} :%Z)u:~':  
} N0fE*xo  
} ed,+Slg  
,,XHw;{  
w;
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//打印回应的头信息 m";8 nm  
public void logResponseHead(HttpURLConnection con) z=k*D^X  
{ ZbH6$2r  
for(int i=1;;i++) D622:Y886  
{ Zo-Au  
String header=con.getHeaderFieldKey(i); zh !/24p9  
if(header!=null) JmF`5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); -GgV&%'a  
Utility.log(header+" : "+con.getHeaderField(header)); oi3Ix7  
else pfim*\'  
break; dkEnc  
} ]H:K$nmX  
} i\36 s$\  
[u3^R]  
UIQ=b;J9  
public void splitterStop() *|+ ~V/#  
{ kGq<Zmy|  
bStop = true; VAxk?P0j6  
} _}Gs9sHr0K  
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} cNN_KA  
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RmN\;G?}  
/* "2"*3R<Y  
**FileAccess.java )fZ5.W8UE]  
*//文件访问(定位，写) JvUHoc$sI  
package NetFox; Us9$,(3  
import java.io.*; ,@gDY9Q3r/  
.>zkS*oX4z  
b!37:V\#}  
public class FileAccessI implements Serializable{ ]  )x z  
Iq": U  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9aqFdlbY  
RandomAccessFile oSavedFile; ~?A,GalS  
long nPos; cmh/a~vYaY  
#iGz&S3iN$  
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public FileAccessI() throws IOException ^_ZQf  
{ :kI x?cc  
this("",0); .uagD[${  
} d>4e9M"  
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public FileAccessI(String sName,long nPos) throws IOException HNoh B4vt  
{ Ip0@Q}^
 
oSavedFile = new RandomAccessFile(sName,"rw"); b_Ky@kp  
this.nPos = nPos; eEe8T=mD  
oSavedFile.seek(nPos); ]i]sgg[  
} ?t.?f`(|  
Hp> J,m(*  
L{CHAVkV  
public synchronized int write(byte[] b,int nStart,int nLen) g?o$:>c  
{ /[#{#:lo2  
int n = -1; L@R%*-a  
try{ <^ )0M  
oSavedFile.write(b,nStart,nLen); 1}q[8q  
n = nLen; vrW9<{  
} z8"=W,2  
catch(IOException e) |V~P6o(/  
{ &akMj@4;R  
e.printStackTrace (); s9:2aLZ{  
} Y.*lO  
Q}Vho.N@=  
!%M-w0vC9  
return n; S(-=I!.G{  
} iii$)4V  
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't_=%^q  
} c!\y\r  
$BBfsaJPT  
/s*
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/* \T]"pE+8l  
**SiteInfoBean.java UZX)1?U  
*/ >qUO_>  
package NetFox; 8"*$e I5  
GRV9s9^  
j1iC1=`ZM  
public class SiteInfoBean { Q6W)rJ[|  
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private String sSiteURL; //Site's URL ;^8^L'7cr  
private String sFilePath; //Saved File's Path f"0H9  
private String sFileName; //Saved File's Name Yh%wf3 UEO  
private int nSplitter; //Count of Splited Downloading File Tk2kis(n  
xNqQbkF  
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public SiteInfoBean() B# H  
{//nSplitter的缺省值为5 IFTW,9hh  
//default value of nSplitter is 5 YXg uw7%\  
this("","","",5); M2EN(Y_k0  
} ?Ru`ma\;  
^{K8uN7  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) I!<v$  
{ Qy/bzO  
sSiteURL= sURL; c_
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sFilePath = sPath; +l/j6)O`(m  
sFileName = sName; S'JeA>L  
this.nSplitter = nSpiltter; KE&}*Nf[  
qtH&]Suu,  
pz IMj_  
} yl 8v&e{  
omA*XXUx=8  
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public String getSSiteURL() Fi/G, [q  
{ |O9=C`G_  
return sSiteURL; # |I@`#O  
} 8W[]#~77b  
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public void setSSiteURL(String value) B
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{ _Lb& 2PAG  
sSiteURL = value; EDQJ>c  
} r"[T9  
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|YFD|  
public String getSFilePath() `j<tI6[e  
{ ?^vZ{B)&0E  
return sFilePath; f,a %@WT  
} Lb{D5k*XU  
y&Hh8|'mC  
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public void setSFilePath(String value) 19u?^w  
{ Aii[=x8  
sFilePath = value; ] zY  
} WO9/rF_  
bC{8yV=)  
 :Y
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public String getSFileName() m'B6qy!}6  
{ MX0B$yc$  
return sFileName; T!a[@,)_  
} RGLA}|  
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public void setSFileName(String value) 6v#G'M#r  
{ !v L:P2  
sFileName = value; `@D4?8_  
} !gf3%!%  
UVJ(iNK"  
VC(|t} L4  
public int getNSplitter() sEN@q  
{ 3Q}Y?rkJ5  
return nSplitter; *$$V,6O.  
} >[@d&28b%  
pb Ie)nK  
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public void setNSplitter(int nCount) (`+Z'Y  
{ xlO2jSSAt  
nSplitter = nCount; <6~;-ZQY  
} \pGO}{3e*  
} Z5[:Zf?h7J  
sK?-@  
j2M(W/_
 
/*
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**Utility.java 6w;|-/:`  
*/ )x&@j4,  
package NetFox; OF/)-}!  
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|=T<WU1$  
public class Utility { q*nz4QTOE  
W@dY:N}  
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public Utility() T6roz  
{ p&mtKLv  
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np^<HfYV  
} p'k+0=  
7~nCK  
//线程睡眠 E0]h|/A]  
public static void sleep(int nSecond) 34kd|!e,  
{ [B @j@&  
try{ veg!mY2&  
Thread.sleep(nSecond); CZRo{2!?U  
} \Egc5{   
catch(Exception e) (v:ek_  
{ !F#aodM1N  
e.printStackTrace (); qjzW9yV+  
} wP0+Xv,  
} :&)/vq  
ld}$Tsy0  
//日志 A i){,nh`0  
public static void log(String sMsg) >wO$Vu `t  
{ ]GPJ(+5  
System.err.println(sMsg); otD?J= B  
} *yq]  
zn1Rou]6  
~C7<a48x  
public static void log(int sMsg) ;OU>AnWr(&  
{ ;;hyjFGq%  
System.err.println(sMsg); ]NV ]@*`tO  
} zf>^2t*\  
} XuoEAu8]  
|;m`874  
0DVZRB  
/*  &Z!K]OSY  
**TestMethod.java H&Y{jqua  
*/ Y*cJ4hQ  
package NetFox; >-5Gt  
SuH.lCF-g  
M6iO8vY  
public class TestMethod { yL x .#kx6  
vSC0D7BlG  
OrEuQ-,i@  
public TestMethod() k5;Vl0Ho  
{ ///xx/weblogic60b2_win.exe KI@    
try{ xf"5<PTW</  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6.h  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); k+#l;<\2  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5vX8mPR_  
fileFetch.start(); _
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}  L|lmStwe  
catch(Exception e){e.printStackTrace ();} o?mXxL)  
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"E)++\JL  
} AYA&&b  
W#jZRviyq!  
tWSvxGCzn%  
public static void main(String[] args) R
=9~*9  
{ u@_!mjXQ  
new TestMethod(); =Cy>$/H64  
} tK|9qs<%  
} t)gi.Ed1"L  
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