http断点续传简单实现（java)

/* W
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**SiteFileFetch.java A9l})_~i  
*/ {_XrZ(y/  
package NetFox; o;4e)tK  
import java.io.*; BT#=Xh  
import java.net.*; k3>ur>aW  
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public class SiteFileFetch extends Thread { AOlt,MNpQ  
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SiteInfoBean siteInfoBean = null; //文件信息Bean hQ}7Z&O  
long[] nStartPos; //开始位置 c\)&yGE  
long[] nEndPos; //结束位置 Xvj=*wg\Y  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 f UF;SqT  
long nFileLength; //文件长度 ?(/j<,m^  
boolean bFirst = true; //是否第一次取文件 mDF"&.(j  
boolean bStop = false; //停止标志 seuN,jpt  
File tmpFile; //文件下载的临时信息 ]a6O(]  
DataOutputStream output; //输出到文件的输出流 FfxX
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） GtM( Y  
public SiteFileFetch(SiteInfoBean bean) throws IOException 7}'A)C>J;  
{ Vv
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siteInfoBean = bean; 33<fN:J]f  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); e@:P2(WWl  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?l, X!o6  
if(tmpFile.exists ()) qH h'l;.  
{ q]N?@l]  
bFirst = false; }>;ht5/i/  
read_nPos(); wHOlj)CZ  
} o\]:!#r{T  
else cF_;hD|YZ  
{ FS
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nStartPos = new long[bean.getNSplitter()]; \7t5U7v8U  
nEndPos = new long[bean.getNSplitter()]; `?]rr0.}hp  
} uojh%@.4  
! nCjA\$  
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} %]chL.s  
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public void run() xz"Z3B  
{ ke}Y
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//获得文件长度 ,ykPQzO  
//分割文件 4FIV  
//实例FileSplitterFetch 3"'# |6O9  
//启动FileSplitterFetch线程 bvipbf[m<  
//等待子线程返回 QOT)x4!)  
try{ Ns.3s7&  
if(bFirst) r*6"'W>c6  
{ ;V(H7 ZM  
nFileLength = getFileSize(); BEXQTM3])I  
if(nFileLength == -1) h"u<E\g  
{ 9U|<q  
System.err.println("File Length is not known!"); y8w0eq94  
} msc 1^2  
else if(nFileLength == -2)  's>#8;X  
{ ,C{^`Bk-W  
System.err.println("File is not access!"); ~JwpNJs  
} ShWHHU(QQ  
else Jt2,LL:G  
{ /lLov.  
for(int i=0;i<nStartPos.length;i++) ` URSv,(  
{ 8"km_[JE e  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); c$Xe.:QY  
} (VYR
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for(int i=0;i<nEndPos.length-1;i++) 9Hf*cQ  
{ cW)Oi^q%o2  
nEndPos = nStartPos[i+1]; h_&4p=SQ  
} L
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nEndPos[nEndPos.length-1] = nFileLength; U@.u-)oX  
} ;RWW+x8IB  
} 8%o~4u3  
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//启动子线程  2Vp>"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; X,RT<GNNb  
for(int i=0;i<nStartPos.length;i++) (
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{ 87^:<\pp  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \npz.g^c_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), W\it+/  
nStartPos,nEndPos,i); ;".z[l*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); k
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fileSplitterFetch.start(); 9?uqQ  
} :O9P(X*  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), koOyZ>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); jrm0@K+<IA  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", H<`^w)?  
nEndPos = " + nFileLength); 2X|CuL{]  
// fileSplitterFetch[nPos.length-1].start(); O.*jR`
l  
{ EA2  
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//等待子线程结束 ~TYbP  
//int count = 0; o"
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//是否结束while循环 .aNO( /kO  
boolean breakWhile = false; j#N(1}r=1  
}*iAE>;  
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while(!bStop) luW <V>  
{ h ZoC _\  
write_nPos(); (E!%v`_0
 
Utility.sleep(500);
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breakWhile = true; xME(B@j  
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for(int i=0;i<nStartPos.length;i++) o;3j:#3 |  
{ fO*)LPen.z  
if(!fileSplitterFetch.bDownOver) " Wp   
{ <O;&qT*b  
breakWhile = false; qh%i5Mu  
break; oG!6}5  
} ~6p5H}'H1  
} 6|QTS|!  
if(breakWhile) P,(9cyS{  
break; ~\2;i]|  
ucw`;<d8  
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//count++; t-_#Q bzE{  
//if(count>4) XmP;L(wa  
// siteStop(); avlqDi1l  
} F y b[{"  
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System.err.println("文件下载结束！"); <BSSa`N`  
} rB,ld
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catch(Exception e){e.printStackTrace ();} >gr<^$
 
} O{~KR/  
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^Sw2xT$p{j  
//获得文件长度 Q*gnAi&.#  
public long getFileSize() D>P;Izb  
{ }@wVW))6$  
int nFileLength = -1; #+$ zE#je  
try{ ?fV?|ZGZ
I  
URL url = new URL(siteInfoBean.getSSiteURL()); {o( * f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G(3;;F7"  
httpConnection.setRequestProperty("User-Agent","NetFox"); /^Y[*5  
GjEqU;XBi  
012Lwd  
int responseCode=httpConnection.getResponseCode(); 6;gLwOeOHY  
if(responseCode>=400) 1t.R+1[c  
{ 6Z Xu,ks}  
processErrorCode(responseCode); x.b
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return -2; //-2 represent access is error
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} z?)He)d  
^CUSlnB\(  
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String sHeader; 7SaiS_{:  
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0Q7MM6  
for(int i=1;;i++) sdrWOq  
{ )AI?x@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); "TfI+QgLF  
//Utility.log(in.readLine()); !~)90Z!  
sHeader=httpConnection.getHeaderFieldKey(i); u\f3qc,]F  
if(sHeader!=null) B_hPcmB  
{ d.p'pGL  
if(sHeader.equals("Content-Length"))  c-5Ysg  
{ =5?.'XMk  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `%Q&</X  
break; wqP2Gw7jh6  
} >VP5vkv=  
} z|I0-1tAK  
else dq(E&`SzK  
break; i3P9sdTD  
} Hs$'0:  
} `^x9(i/NE  
catch(IOException e){e.printStackTrace ();} H'Nq#K  
catch(Exception e){e.printStackTrace ();} Jld\8=  
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Utility.log(nFileLength); >k;p.Pay%  
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return nFileLength; KzNm^^#/$A  
} { D+Ym%n  
Z|I
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DHv2&zH  
//保存下载信息（文件指针位置） ^^U%cuKg  
private void write_nPos() !>3LGu,  
{ ;}K62LSR  
try{ 6J\fF tB@V  
output = new DataOutputStream(new FileOutputStream(tmpFile)); RU|X*3";T  
output.writeInt(nStartPos.length); i'=2Y9S}  
for(int i=0;i<nStartPos.length;i++) ,:UX<6l R  
{ q_sEw~~@!  
// output.writeLong(nPos); a.q;_
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output.writeLong(fileSplitterFetch.nStartPos); x#r<,uNn,  
output.writeLong(fileSplitterFetch.nEndPos); nR[^|CAR  
} rEM#D]k  
output.close(); at| \FOKj  
} H:
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catch(IOException e){e.printStackTrace ();} [1SMg$@<  
catch(Exception e){e.printStackTrace ();} |cgui  
} cS(;Qs]Q  
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//读取保存的下载信息（文件指针位置） 8
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private void read_nPos() hF>u)%J/S  
{ @PX\{6&  
try{ 2"X~ju  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); id?E)Jy  
int nCount = input.readInt(); 2.nE k  
nStartPos = new long[nCount]; <*wM=aq  
nEndPos = new long[nCount]; 8{ gXToK  
for(int i=0;i<nStartPos.length;i++) psUE!~9,  
{ nZ E)_  
nStartPos = input.readLong(); %j5ywr:  
nEndPos = input.readLong();  to>  
}
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input.close(); v+6e;xl8  
}  z)w-N  
catch(IOException e){e.printStackTrace ();} Dpv
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catch(Exception e){e.printStackTrace ();} <#*.}w~  
} 3{ "O,h  
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private void processErrorCode(int nErrorCode) u-:Ic.ZV  
{ j_GBH8`  
System.err.println("Error Code : " + nErrorCode); >;9NtoE  
} IZrk1fh  
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5JSrrpGr
 
//停止文件下载 y vI<4F  
public void siteStop() "@yyXS r  
{ X{Zm9T  
bStop = true; J'Sm
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for(int i=0;i<nStartPos.length;i++) :mZYS4L~  
fileSplitterFetch.splitterStop(); Bm/
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r,;\/^u*  
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} i=rH7k  
} .<YcSG  
//负责部分文件的抓取 BJy;-(JP  
**FileSplitterFetch.java +>tUz D  
*/ g7n"  
package NetFox; ?fK1  
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import java.io.*; U(,.D}PG  
import java.net.*; :_HF j.JW  
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public class FileSplitterFetch extends Thread {
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String sURL; //File URL MKg,!TELe  
long nStartPos; //File Snippet Start Position t'(1I|7  
long nEndPos; //File Snippet End Position 7x k|+!  
int nThreadID; //Thread's ID /+[63
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boolean bDownOver = false; //Downing is over 1@qgF  
boolean bStop = false; //Stop identical +B"0{>n}F  
FileAccessI fileAccessI = null; //File Access interface ;rR/5d1!  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ar^i|`D  
{ $k%Z$NSN=  
this.sURL = sURL; :YO@_  
this.nStartPos = nStart; RE"^ )-  
this.nEndPos = nEnd; -d=WV:G%e  
nThreadID = id; eUBrzoCO  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 @S3f:s0~D
 
} Yj3I5RG  
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public void run() )^x K   
{ vhgLcrn  
while(nStartPos < nEndPos && !bStop) {C3Y7<  
{ 3yO=S0`  
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try{ ~Xv=9@,h  
URL url = new URL(sURL); qJv[MBjk3B  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); r'4:)~]s  
httpConnection.setRequestProperty("User-Agent","NetFox"); eJ@~o{,?>  
String sProperty = "bytes="+nStartPos+"-"; GbZ;#^S  
httpConnection.setRequestProperty("RANGE",sProperty); K=\O5#F?3  
Utility.log(sProperty);  jNyoN1M  
#&8rcu;/  
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InputStream input = httpConnection.getInputStream(); iK;opA"  
//logResponseHead(httpConnection); \R
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9A$m$  
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byte[] b = new byte[1024]; h<l1U'Bn7  
int nRead; %,q.),F  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) anN#5jt  
{ <48<86TP  
nStartPos += fileAccessI.write(b,0,nRead); \}"m'(\c  
//if(nThreadID == 1) 0C$vS`s&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); cP>o+-)  
} m$2<`C=  
q1{H~VSn"  
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Utility.log("Thread " + nThreadID + " is over!"); nk=$B(h  
bDownOver = true; \2e0|)aF6  
//nPos = fileAccessI.write (b,0,nRead); zGlZ!t:  
} L}k/9F.5  
catch(Exception e){e.printStackTrace ();} K_&MoyJJ9f  
} 9S7A!AKE  
} h2q/mi5{  
>Aq:K^D/3F  
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//打印回应的头信息 pPro }@@  
public void logResponseHead(HttpURLConnection con) L^`}J7r  
{ |oFAGP1  
for(int i=1;;i++) 2N [=  
{ CI7A# 6-  
String header=con.getHeaderFieldKey(i); b/("Y.r=  
if(header!=null) 6W2hr2Zy9  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4'>1HW  
Utility.log(header+" : "+con.getHeaderField(header)); _lxco=qd=%  
else j?i#L}.I  
break; S?0$?w?  
} l.=p8-/$'7  
} g=8un`]7  
!q"cpL'4  
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public void splitterStop() !cX[-}Q  
{ YT
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bStop = true; R^&q-M=O[  
} 8Cx^0  
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} "&+3#D >  
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/* +0$/y]k  
**FileAccess.java r%]Qlt~K  
*//文件访问(定位，写) Jh/ E@}'  
package NetFox; X` YwP/D  
import java.io.*; ]+Ixi o  
iJh!KEy~A5  
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public class FileAccessI implements Serializable{ 5TKJWO.  
OjE`1h\  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 wIvo"|%  
RandomAccessFile oSavedFile; Vm1-C<V9  
long nPos; A<MtKb  
`)$_YZq|SR  
VR?^HA9  
public FileAccessI() throws IOException 19e
8
 
{ 7Ke&0eAw  
this("",0); Jf;?XP]z  
} ){;02^tX  
kL*0M<0 (  
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public FileAccessI(String sName,long nPos) throws IOException N@T.T=r  
{ ed!>)Cb  
oSavedFile = new RandomAccessFile(sName,"rw"); V A^l+Z,d  
this.nPos = nPos; pW\'ZRj  
oSavedFile.seek(nPos); )X+mV  
} [5d2D,)  
 a*dQ _  
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public synchronized int write(byte[] b,int nStart,int nLen) ^%T7.1'x  
{ io2)1cE&f  
int n = -1; R!\EKH  
try{ .p` pG3  
oSavedFile.write(b,nStart,nLen); u'~;Y.@i'  
n = nLen; 5`+5{p  
} ~%k?L4%  
catch(IOException e) ~p1EF;4#  
{ X@2-*so<
 
e.printStackTrace (); _"a=8a06G  
} pJIv+  
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"f.Z}AbP  
return n; IZ,oM!Y  
} |,C#:"z;  
}WLh8i?_  
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} JH,/jR  
sYSLmUZ{  
RzKb{> ;A  
/* NPnHH:\;  
**SiteInfoBean.java %:v`EjRD0  
*/ =qVP] 9  
package NetFox; ~#K@ADYr  
gk0.zz([  
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public class SiteInfoBean { g2cVZ!GIj  
xb
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private String sSiteURL; //Site's URL T.e.{yO  
private String sFilePath; //Saved File's Path 7j<e)"  
private String sFileName; //Saved File's Name Dr3n+Q  
private int nSplitter; //Count of Splited Downloading File m|tC24  
DbI!l`Vn4  

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public SiteInfoBean() {lG@h
N'
 
{//nSplitter的缺省值为5 E$s/]wnr[  
//default value of nSplitter is 5 M)-6T{[IT  
this("","","",5); >pyj]y^3  
} Njc%_&r  
dhPKHrS  

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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) NcS.49  
{ ;Y9=!.Ak0y  
sSiteURL= sURL; ff?t[GS  
sFilePath = sPath; Rg&-0b  
sFileName = sName; )}v3q6?_  
this.nSplitter = nSpiltter; R9vT[{!i  
$"JpFT  
NR%Y+8^M  
} ,Z9>h[JF  
iOw3MfO  
gbBy/_b  
public String getSSiteURL() unl1*4e+  
{ K]oM8H1  
return sSiteURL; E`\8TqO  
} C2U~=q>>  
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0Wvq>R.(]7  
public void setSSiteURL(String value) B0}~G(t(  
{ -XK0KYhgW  
sSiteURL = value; F4#g?R::U  
} YB))S!;Ok  
^WYQ]@rh3  
QWnndI_4p  
public String getSFilePath() R@Y=o].2  
{ MZv]s  
return sFilePath; `|O yRU"EK  
} 3k$[r$+"  
0X|_^"!  
GV|9H]_,I  
public void setSFilePath(String value) AnsjmR:Jv  
{ _;9!  
sFilePath = value; Xt/Ksw"wn  
} |
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BG`s6aC|z<  
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public String getSFileName() =s97Z-  
{ VL+C&k v]  
return sFileName; $& ~;@*[  
} 4Cb9%Q0  
,<,:8B  
&a)eJF]:!  
public void setSFileName(String value) E|EgB33S  
{  NW9n  
sFileName = value; ?8@>6IXn  
} u0)7i.!M  
p0p4Xh1e  
'X
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public int getNSplitter() 8iQ[9  
{ mABe'"8  
return nSplitter; _W!p8cB  
} b4 #R!  
h[tix:  
-<_$m6x"A  
public void setNSplitter(int nCount) a~LC+8|JW  
{ A1Y7
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nSplitter = nCount; <G8w[hs  
} KU9Z"9#  
} Rf %HIAVE  
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NtGn88='{  
/* Y
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**Utility.java er.L7  
*/ |aToUi.Q%  
package NetFox; x<i}_@Sn_+  
{U!St@  
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public class Utility { U!5)5c}G  
neF]=uCWnT  
bF}V4"d,B3  
public Utility() `<"m%>  
{ Rhzn/\
)|  
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} 1t[j"CG(o  
pY8q=Kl  
//线程睡眠 KGHq rc  
public static void sleep(int nSecond) =ziwxIo6  
{ U!w1AY|  
try{ nQK|n^AU/  
Thread.sleep(nSecond); hv$yV%.`  
} E .6HpIx  
catch(Exception e) 4A`NJ  
{ -|yb[~3  
e.printStackTrace (); Tsb{25`+  
} ,"}Rg1\4t  
} yI{5m^s{  
_A_ A$N~9  
//日志 p\vMc\  
public static void log(String sMsg)
Q-TV*FD.  
{ s Wjy6;  
System.err.println(sMsg); c8 K3.&P6  
} ewsKH\#  
]LPQYL  
cFd >oDS  
public static void log(int sMsg) X*oMFQgP  
{
*DI)?  
System.err.println(sMsg); v`q\6i[-  
} 2i#Sn'1  
} (kBP(2V  
?|;yVew
 
0Sl]!PZR1  
/* 72TI  
**TestMethod.java 3+7^uR$/I4  
*/ =;~I_)Pg1  
package NetFox; 1{"ll
D  
?z-}>$I;  
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public class TestMethod { OvL\u{(<F  
5wtTP ;P  
']6VB,c`  
public TestMethod() JHn*->m  
{ ///xx/weblogic60b2_win.exe R614#yn-+  
try{ >"X\>M`"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); s'P( ,!f  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); bJr[I  
SiteFileFetch fileFetch = new SiteFileFetch(bean); u?+bW-D'd  
fileFetch.start();  Wa/g`}  
} 3M*Bwt;F_  
catch(Exception e){e.printStackTrace ();} }w-
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} !v#xb3"/  
fg%&N2/(.B  
8U2dcx:G3  
public static void main(String[] args) VU|dV\>  
{ j|.} I  
new TestMethod(); V)o,1  
}   \J^  
} 1,y&d}GW  
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