http断点续传简单实现（java)

/* WB2An7i@"{  
**SiteFileFetch.java k !S0-/h  
*/ S`oADy  
package NetFox; O\h*?, )  
import java.io.*; /Q4TQ\:  
import java.net.*; (j^Qa~{mG4  
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public class SiteFileFetch extends Thread { Jhclg0q  
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SiteInfoBean siteInfoBean = null; //文件信息Bean g]IRv(gDh  
long[] nStartPos; //开始位置 la7VeFT  
long[] nEndPos; //结束位置 }Fd4; ]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7~@9=e8G  
long nFileLength; //文件长度 #V[j Q Vl  
boolean bFirst = true; //是否第一次取文件 d{cd+An  
boolean bStop = false; //停止标志 Bb5|+bP  
File tmpFile; //文件下载的临时信息 B? $9M9  
DataOutputStream output; //输出到文件的输出流 *C81DQ  
9 )1 8  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 2lVJ"jg  
public SiteFileFetch(SiteInfoBean bean) throws IOException /;7\HZ$@/  
{ ~c&ygL3  
siteInfoBean = bean; 3;@/`Z_\lt  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 'OIOl  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !}Sf?nP#  
if(tmpFile.exists ()) >wz&{9ni  
{ G%{J.J41F  
bFirst = false;  |,*N>e  
read_nPos(); u^DfRd&P0  
} LU
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else DJxe3<  
{ :DI``]Si\  
nStartPos = new long[bean.getNSplitter()]; KMO(f!?  
nEndPos = new long[bean.getNSplitter()]; i6L>,^Dg  
} `nAR/Ye  
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} m0}Pq{g  
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public void run() OAoTsqj6  
{ f)`_su U  
//获得文件长度 \J*~AT~5q  
//分割文件 (twwDI  
//实例FileSplitterFetch p
"A2N+  
//启动FileSplitterFetch线程 sw<mmayN  
//等待子线程返回 rI/;L<c  
try{ ~#z8Q{!O  
if(bFirst) b@G
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{ bXVH7Fy  
nFileLength = getFileSize(); /.54r/FN')  
if(nFileLength == -1) ZY_aE  
{ F E`4%X  
System.err.println("File Length is not known!"); v2OK/W,0  
} (x;Uy  
else if(nFileLength == -2) :
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{ -~ w5yd  
System.err.println("File is not access!"); 8+HXGqcv  
} Q"o* \I  
else
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{ &J>XKO nl  
for(int i=0;i<nStartPos.length;i++) lD`@{A  
{ O*
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); >3{#S:  
} q1rBSlzN  
for(int i=0;i<nEndPos.length-1;i++) DRp h?V\  
{ Mnj\t3:  
nEndPos = nStartPos[i+1]; 9|kc$+(+6  
} L#t^:%  
nEndPos[nEndPos.length-1] = nFileLength; 0:NCIsIm<  
} RKIBFP8.  
} &hTe-Es  
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nK95v}p}Y  
//启动子线程 Gi=sJV  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Ue:LKK1Gsr  
for(int i=0;i<nStartPos.length;i++) vBFMne1h  
{ y {&"g  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /wt!c?wR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), vy:-a G  
nStartPos,nEndPos,i); GSHJ?}U,  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %pikt7,Z~  
fileSplitterFetch.start(); (8JL/S;Z$  
} K1
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), g
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Ge'[AhA  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", c@eQSy  
nEndPos = " + nFileLength); $N !l-lu=  
// fileSplitterFetch[nPos.length-1].start(); @u@N&{b5"  
\`ya08DP(  
8i epG  
//等待子线程结束 )JNUfauyT  
//int count = 0; m`;dFL7"E  
//是否结束while循环 rI'kGqU  
boolean breakWhile = false; ^bD)Tg5K  
*Z9Rl>  
DGc5Lol~  
while(!bStop) 9Dat oi  
{ !^[i"F:G  
write_nPos(); AVn?86ri  
Utility.sleep(500); 0mt lM(  
breakWhile = true; UFE# J  
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for(int i=0;i<nStartPos.length;i++) +'-i(]@!'  
{ 6dH> 0
l  
if(!fileSplitterFetch.bDownOver) 1{fu  
{ [Re.sX}$Y  
breakWhile = false; _nUvDdEs,  
break; =pT}]  
} `@_jDo  
} buj*L&  
if(breakWhile) K~chOX  
break; a^#\"c  
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O:%,.??<%  
//count++; q0m>NA   
//if(count>4) b] EC+.  
// siteStop(); {)CN.z:O  
} [=EmDP:@  
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5~R1KjjvA  
System.err.println("文件下载结束！"); oCxh[U@*D  
} ,J@A5/B,AA  
catch(Exception e){e.printStackTrace ();} \kR:GZ`{UV  
} kd=|Iip;(  
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//获得文件长度 y/.I<5+Bu  
public long getFileSize() -:V0pb  
{ hifC.guK  
int nFileLength = -1; E"'4=_  
try{ a_T3<  
URL url = new URL(siteInfoBean.getSSiteURL()); J<vVsz+7:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'kBq@>  
httpConnection.setRequestProperty("User-Agent","NetFox"); dzbFUDJ  
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BJDSk#!J!{  
int responseCode=httpConnection.getResponseCode(); 7l+:gD  
if(responseCode>=400) +Oafo|%  
{ G m~2s;/  
processErrorCode(responseCode); DtFzT>$^F  
return -2; //-2 represent access is error } %bP9  
} _SQQS67fu"  
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 Z,"f2UJ  
String sHeader; #dj,=^1_14  
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for(int i=1;;i++) N51e.;  
{ xf7_|l  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); nB9(y4  
//Utility.log(in.readLine()); FoX,({*Ko~  
sHeader=httpConnection.getHeaderFieldKey(i); AxAbU7m  
if(sHeader!=null) %E"dha JY  
{ PR2;+i3  
if(sHeader.equals("Content-Length")) )JXlPU  
{ c}G\F$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =M],5<2;  
break; >(\Z-I&YQ  
} Q`zW[Y&]  
} >Tp`Kri  
else 0F-%C>&g  
break; bjr()NM1  
} 4(%LG)a4S  
} ~7$jW[i  
catch(IOException e){e.printStackTrace ();} 4>NmJrh  
catch(Exception e){e.printStackTrace ();} oXgi#(y  
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Utility.log(nFileLength); CeINODcT  
o:
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return nFileLength; \"|7o8  
} vUR@P -  
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TMG|"|  
//保存下载信息（文件指针位置） 8D&yFal  
private void write_nPos() SH5a&OVZhn  
{ 1~
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try{ yt{?+|tXU  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )1E#'v12"  
output.writeInt(nStartPos.length); Ca}V5O  
for(int i=0;i<nStartPos.length;i++) l_i&8*=Px  
{ >*h3u7t  
// output.writeLong(nPos); |0nt u+  
output.writeLong(fileSplitterFetch.nStartPos); %
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output.writeLong(fileSplitterFetch.nEndPos); $)Ty@@7C  
} 'pHxO,vo  
output.close(); y4N2gBTKu  
} il[waUfmD  
catch(IOException e){e.printStackTrace ();} +lhnc{;WJv  
catch(Exception e){e.printStackTrace ();} /
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} y1bo28  
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:I(d-,C  
//读取保存的下载信息（文件指针位置） sEHA?UP$<F  
private void read_nPos() X!|K 4Z!k  
{ >9Z7l63+}  
try{ zI$'D|A  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); YZZog6%  
int nCount = input.readInt(); jL0=a.;  
nStartPos = new long[nCount]; vEc<|t  
nEndPos = new long[nCount]; c+ukVn`r  
for(int i=0;i<nStartPos.length;i++) Y(;u)uN_  
{
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nStartPos = input.readLong(); c@x6<S%*  
nEndPos = input.readLong(); mCSt.n~  
} F
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input.close(); 
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} dYZB> OS  
catch(IOException e){e.printStackTrace ();} i}/Het+(  
catch(Exception e){e.printStackTrace ();} jk{m8YP)E  
} C#@-uo2  
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private void processErrorCode(int nErrorCode) jGEmf<q&u  
{ |F49<7XB[~  
System.err.println("Error Code : " + nErrorCode); fS]Z`U"
 
} /kV5~i<1S  
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//停止文件下载 ,!QtViA7  
public void siteStop() Huc|HL#C  
{ Vx%!j&  
bStop = true; I_is3y0  
for(int i=0;i<nStartPos.length;i++) 3oM&#a  
fileSplitterFetch.splitterStop(); tR<L9h  
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} fF^A9{{BS  
} ;{1
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//负责部分文件的抓取 :KI0j%>2y  
**FileSplitterFetch.java ;umbld0  
*/ 4ah5}9{g  
package NetFox; vRLWs`1j  
5s:g(gy3BR  
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import java.io.*; [tkP2%1  
import java.net.*; BFQ`Ab+  
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public class FileSplitterFetch extends Thread { (!%w  
,[[Xo;q  
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String sURL; //File URL B:6VD /qC  
long nStartPos; //File Snippet Start Position 0,wmEV!)  
long nEndPos; //File Snippet End Position 1"No~/_  
int nThreadID; //Thread's ID co*XW  
boolean bDownOver = false; //Downing is over %=)%$n3=-M  
boolean bStop = false; //Stop identical W#foVAi .  
FileAccessI fileAccessI = null; //File Access interface QPX3a8w*  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException w01u~"E  
{ (^$SMuC
 
this.sURL = sURL; @@& ?,3  
this.nStartPos = nStart; ,"f2-KC4h  
this.nEndPos = nEnd; >2mV{i&  
nThreadID = id; fJ;1ii~  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 pg3h>)$/  
} ^TT_BAI  
>g,i"Kg  
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public void run() $$eBr8  
{ vvP]tRZ  
while(nStartPos < nEndPos && !bStop) Bkdt[qDn5P  
{ -H$C3V3]  
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#@<L$"L  
try{ pDt45   
URL url = new URL(sURL);  g:?p/L  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -*;JUSGh  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5}:`CC2,S~  
String sProperty = "bytes="+nStartPos+"-"; Qb@i_SX(fs  
httpConnection.setRequestProperty("RANGE",sProperty); ^4=%~Yx  
Utility.log(sProperty); Asli<L(?`  
}^azj>p5  
1SG^X-(GM/  
InputStream input = httpConnection.getInputStream(); :`Xg0J+P  
//logResponseHead(httpConnection); ~T9wx  
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byte[] b = new byte[1024]; cG5u$B  
int nRead; Hu"TEhW(2  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) I[P_j`aE  
{ $ZRvvm!f  
nStartPos += fileAccessI.write(b,0,nRead); *mkL>v &  
//if(nThreadID == 1) gaR~K  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y)b=7sU  
} v_,'NA0  
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Utility.log("Thread " + nThreadID + " is over!"); |)%;B%  
bDownOver = true; V(0V$&qipc  
//nPos = fileAccessI.write (b,0,nRead); N^zFKDJG  
} TH*}Ja^/  
catch(Exception e){e.printStackTrace ();} vvF]g.,  
} lMe+.P|  
} S^nI=H
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>~})O&t  
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//打印回应的头信息 0lS=-am  
public void logResponseHead(HttpURLConnection con) Nq#B4Zx  
{ {tUxRX  
for(int i=1;;i++) =$#=w?~%  
{ rVB\\  
String header=con.getHeaderFieldKey(i); N;* wd<  
if(header!=null) ->2m/d4a  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); r?HbApV P  
Utility.log(header+" : "+con.getHeaderField(header)); GxA[N

 
else QFIYnxY9  
break; 6b\JD.r*{  
} 4oN*J +"=+  
} RAFdo  
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2!GyQ@&[W  
public void splitterStop() |A#\5u  
{ Ym 1; /'  
bStop = true; V:2{LR<R8  
} 3y y
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} a6 w'.]m  
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/* f'OcW*t  
**FileAccess.java ov,[F<GT  
*//文件访问(定位，写) &)!4rABn  
package NetFox; _J>!K'Dz  
import java.io.*; .Xk#Cwm'  
a$$aM2.2  
r+,JM L
 
public class FileAccessI implements Serializable{ ;jFUtG  
:\~YbA  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8BX9JoDi  
RandomAccessFile oSavedFile; vo^2k13  
long nPos; U$LI~XZM  
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public FileAccessI() throws IOException ebhV;Q.  
{ -AwkP  
this("",0); ^>#@qMw  
} xPzBbe  

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public FileAccessI(String sName,long nPos) throws IOException dlBr2 9  
{ N[kl3h%q  
oSavedFile = new RandomAccessFile(sName,"rw"); lCGEd  3  
this.nPos = nPos; %:\GY
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oSavedFile.seek(nPos); A}_0iwG  
} VbX$\Cs:  
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public synchronized int write(byte[] b,int nStart,int nLen) ;:'ABfs  
{ j9&x#U  
int n = -1; @
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try{ AU<A\   
oSavedFile.write(b,nStart,nLen); yv\ j&B|  
n = nLen; \6;b.&%w2  
} %XH%.Ps/  
catch(IOException e) I$*LMzve  
{
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e.printStackTrace (); petq6)g?  
} =h[;'v{  
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return n; n7hjYNJ  
} ](>YjE0  
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} zin'&G>l  
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/* '}E"Mdb  
**SiteInfoBean.java s"x(i  
*/ OZ}o||/Rc  
package NetFox; \omfWW
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public class SiteInfoBean { [#+klP$  
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cX|(/h,W/  
private String sSiteURL; //Site's URL R_b)2FU1y  
private String sFilePath; //Saved File's Path ZV$!dHW/  
private String sFileName; //Saved File's Name -*W\$P  
private int nSplitter; //Count of Splited Downloading File '3 JVUHn  
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public SiteInfoBean() 2tZ\/6G<  
{//nSplitter的缺省值为5 g&X X@I8+v  
//default value of nSplitter is 5 =m U</F)  
this("","","",5); `Wp y6o  
} Nl9
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"MgTfUIiyD  

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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) )npvy>C'(  
{ UDV6 ##$
 
sSiteURL= sURL; fcw/l,k9  
sFilePath = sPath; '3TfW61]  
sFileName = sName; 51`*VR]`K  
this.nSplitter = nSpiltter; M7//*Q'?  
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} q1Ehl S  
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7e6; |?  
public String getSSiteURL() 8^hbS%s!  
{ QPKY9.Rvv  
return sSiteURL; *OHaqe(*  
} u>[hLXuB  
'[Bok=$B)  
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public void setSSiteURL(String value) VF g"AJf  
{ 3<}r+,j  
sSiteURL = value; _A6e|(.ll  
} }ssL
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+7j7zpw  
public String getSFilePath() WTwur
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{ M^0^l9w  
return sFilePath; q=
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} `]5t'Ps  
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public void setSFilePath(String value) YeB)]$'?u`  
{ HA~BXxa/  
sFilePath = value; ~--F?KUnL  
} `ex>q  
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||'A9  
public String getSFileName() "(vm0@8><  
{ h:4F
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return sFileName; wPr!.:MF  
} 2xt$w%  

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public void setSFileName(String value) fPab%>/T{  
{ @MfZP~T+  
sFileName = value; ML:H\  
} APqYf<W  
(gb vInZ  
W!)B%.Q  
public int getNSplitter() &cT@MV5  
{ `bjPOA(g  
return nSplitter; Zn]!*}  
} Y#rd' 8  
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public void setNSplitter(int nCount) 5
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{ IV|})[n*  
nSplitter = nCount; YeV
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} >?r8D48`  
} $uYfy<  
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!^qpV7./l  
/* HA3d9`  
**Utility.java ~jMfm~  
*/ E/3<8cV  
package NetFox; dd!Q[]$ }  
C$^WW}S  
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public class Utility { KWH:tFL.  
8P*wt'Q$  
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public Utility() ~~{+?v6B]  
{ Gr
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)m>Y[)8!  
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} s@pIcNvx  
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//线程睡眠 9bu1Ax1M  
public static void sleep(int nSecond) pRFlmg@/}  
{ ,`ju(ac!  
try{ zc5>)v LH=  
Thread.sleep(nSecond); %KW NY(m  
} b2UqN]{  
catch(Exception e) JjnWv7W3$  
{ k:*vD"  
e.printStackTrace (); (dAE  
} rz.`$  
} ;!pJ%p0Sc  
#oxP
,LR  
//日志 "eR-(c1  
public static void log(String sMsg) !t|2&R$IQ  
{ pu Z0_1uN  
System.err.println(sMsg); :zsMkdU  
} `f\+aD'u  
,*g.?q@W2  
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public static void log(int sMsg) #EIcP=1m4  
{ fU^5Dl  
System.err.println(sMsg); @~`:sa+H  
} 0 1:(QJ  
} <&iLMb:%  
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-5<G^AS  
/* ?T_bjALW  
**TestMethod.java +"JQ5~7  
*/ |!uC [=  
package NetFox; :\"g}A
X  
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=$
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public class TestMethod { 7x)32f"  
X oh@(%  
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public TestMethod() =7Sw29u<  
{ ///xx/weblogic60b2_win.exe 5~=wia  
try{ gwN y
]!  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); !b'!7p  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !s47A"O&B  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 6yhRcvJ}  
fileFetch.start(); `{'h+v`  
} *2r(!fJP=^  
catch(Exception e){e.printStackTrace ();} tS6r4d%~=  
aIklAj)=  
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} jP"yG#  
Zl{DqC^  
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public static void main(String[] args) Sbjc8V ut  
{ PAs.T4Av^  
new TestMethod(); R6qC0@*  
} BaOPtBYA:  
} 1JF>0ijU@  
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