http断点续传简单实现（java)

/* 0\QYf0o   
**SiteFileFetch.java ]C+eJ0"A  
*/ E#8J+7  
package NetFox; .!!79 6hS  
import java.io.*; q^u6f?B  
import java.net.*; -.^@9 a>  
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public class SiteFileFetch extends Thread { 'wegipK~R  
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SiteInfoBean siteInfoBean = null; //文件信息Bean KhLg*EL  
long[] nStartPos; //开始位置 Mi_[9ku>%  
long[] nEndPos; //结束位置 9#s,K! !3{  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 nz}]C04:-  
long nFileLength; //文件长度 J: L-15  
boolean bFirst = true; //是否第一次取文件 5X0_+DdeL  
boolean bStop = false; //停止标志 u2f `|+1^y  
File tmpFile; //文件下载的临时信息 4p*?7g_WVH  
DataOutputStream output; //输出到文件的输出流 32TP Mk  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） BW+qp3k\  
public SiteFileFetch(SiteInfoBean bean) throws IOException p.qrf7N$  
{ 9 J$Y,Z  
siteInfoBean = bean; &f$a1#O}dx  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); lF)0aDk'h  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ojiM2QT}m  
if(tmpFile.exists ()) YNuewD  
{ 1VRqz5  
bFirst = false; [B.W1 GL!  
read_nPos(); pq%t@j(X  
} wEZqkV  
else p!. /  
{ F%w\D9+P  
nStartPos = new long[bean.getNSplitter()]; E `?S!*jm  
nEndPos = new long[bean.getNSplitter()]; &;'w8_K"^  
} W,0KBkkp  
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} hnH)Jy;>  
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 pb,{$A  
public void run() 4Sd+"3M  
{ 1Kp?bwh"u  
//获得文件长度 0V{>)w!Fo  
//分割文件 TG""eC!E  
//实例FileSplitterFetch >\N$>"~a  
//启动FileSplitterFetch线程 wY."Lw> 6  
//等待子线程返回 Ubn
 
try{ @G^j8Nl+J}  
if(bFirst) :YkDn~@  
{ M'pY-/.  
nFileLength = getFileSize(); 7{?lEQ&UE  
if(nFileLength == -1) BBaHMsr  
{ 54, Ju'r  
System.err.println("File Length is not known!"); BA`kxL
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} }W^V^i)  
else if(nFileLength == -2) 0Og/47dO.2  
{ 3JwSgcb  
System.err.println("File is not access!"); t[L2'J.5  
} s?1-$|*  
else iPRJA{$b_  
{ U"jUMOMZ;  
for(int i=0;i<nStartPos.length;i++) <m|FccvQ  
{ Vs2v j  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); krnvFZRTQ  
} N^nDWK  
for(int i=0;i<nEndPos.length-1;i++) EBN]>zz  
{ C.B8 J"T-  
nEndPos = nStartPos[i+1]; ;jpw"-J`  
} zIX}[l4EW~  
nEndPos[nEndPos.length-1] = nFileLength; 8' WLm  
}  |V*e2w  
} )wyu+_:  
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//启动子线程 [kU[}FT  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; gwkZk-f\p  
for(int i=0;i<nStartPos.length;i++) uWM4O@Qn)d  
{ g[uE@Gaj&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), x_>"Rnv:K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), see'!CjVo2  
nStartPos,nEndPos,i); "N=&
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R[
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fileSplitterFetch.start(); 'Gm!Jblo@  
} K~9 jin  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), am)J'i,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); j$JV(fz  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", G5X|JTzpu<  
nEndPos = " + nFileLength); g/J^K*3]  
// fileSplitterFetch[nPos.length-1].start(); <3J=;.\6  
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//等待子线程结束 "X!_37kQ  
//int count = 0; -&HoR!af  
//是否结束while循环 ~h~r]tV*+  
boolean breakWhile = false; ZFd{q)qe   
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while(!bStop) +eH=;8  
{
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write_nPos(); iIC9rso"Q1  
Utility.sleep(500); U iPVZ@?  
breakWhile = true; f/|a?n2\hm  
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for(int i=0;i<nStartPos.length;i++) rkER`  
{ jw6ng>9  
if(!fileSplitterFetch.bDownOver) j2C^1:s@m  
{ ^{:[^$f:l  
breakWhile = false; aNh1e^j  
break; <jg wdbT"6  
} jAK`96+D~b  
} \)s 3]/"7  
if(breakWhile) r]K
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break; 0v,`P4_k  
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//count++; ]mDsUZf<  
//if(count>4) #|2g{7g*  
// siteStop(); qoyGs}/I8  
} 4$#ia F  
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System.err.println("文件下载结束！"); d#$i/&gE  
} FCw VVF0y  
catch(Exception e){e.printStackTrace ();} 2*cKFv{  
} FnU{C=P  
I "+|cFq.  
19.!$;  
//获得文件长度 ,L;c{[*
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public long getFileSize() N'W>pU  
{ Ij,?G*  
int nFileLength = -1; 9dhFQWz"  
try{ YfYL?G  
URL url = new URL(siteInfoBean.getSSiteURL()); u8)r W  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;z=C^'  
httpConnection.setRequestProperty("User-Agent","NetFox"); :8/M6-EK  
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int responseCode=httpConnection.getResponseCode(); Z6HkQ=A64  
if(responseCode>=400) . KSr@Gz  
{ _jI)!
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processErrorCode(responseCode); x[h<3V"  
return -2; //-2 represent access is error S7~l%G>]b  
} nD{;4$x
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String sHeader; d%|#m)  
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for(int i=1;;i++) c^/?VmCQ}  
{ ?.'oxW   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); rD)v%vvr&`  
//Utility.log(in.readLine()); ?VHwYD.B  
sHeader=httpConnection.getHeaderFieldKey(i); 5v03<m0`y  
if(sHeader!=null) AhFI, x  
{ B7^n30+L  
if(sHeader.equals("Content-Length")) h4xf%vA(;  
{ %EhU!K#[  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^bg
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break; ROiX=i  
} !wufoK  
}
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else ;$&
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break; 2SCf]&  
} {?M*ZRO'  
} '/)_{Ly  
catch(IOException e){e.printStackTrace ();} +,w|
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catch(Exception e){e.printStackTrace ();} iZqFVr&JF  
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Utility.log(nFileLength); loVvr"&g  
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return nFileLength; ,lGwW8$R  
} ?;kc%Rz  
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//保存下载信息（文件指针位置） ~5?n&pF  
private void write_nPos() D&lXi~Z%.  
{ ,Onm!LI=  
try{ lfG&V +S1  
output = new DataOutputStream(new FileOutputStream(tmpFile)); gKH"f%lK  
output.writeInt(nStartPos.length); GHrT?zEX  
for(int i=0;i<nStartPos.length;i++) ,oVBgCf  
{ S:T>oFUot  
// output.writeLong(nPos); n`2"(7Wj  
output.writeLong(fileSplitterFetch.nStartPos); 5/VB'N#7s  
output.writeLong(fileSplitterFetch.nEndPos); `v+O5  
} {Q3#]Vu  
output.close(); 5m;wMW<  
} zEL[%(fnc  
catch(IOException e){e.printStackTrace ();} ?ew]i'9(  
catch(Exception e){e.printStackTrace ();} N=Yi:+  
} ^bw~$*"j
#  
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//读取保存的下载信息（文件指针位置） ^x#RUv  
private void read_nPos() KTREOOu .t  
{ ^mb*w)-p?  
try{ JO$]t|I  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); |
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VFF  
int nCount = input.readInt(); #j5^/*XW  
nStartPos = new long[nCount]; 5?Ao9Q]@  
nEndPos = new long[nCount]; AxQ/  
for(int i=0;i<nStartPos.length;i++) yodrX&"  
{ q\=[
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nStartPos = input.readLong(); 5~6y.S  
nEndPos = input.readLong(); 9Qd'=JQl  
} *qOCo_=P8  
input.close(); ;a77YLTQ  
} &3/H P)*<]  
catch(IOException e){e.printStackTrace ();} jWCC`0 T  
catch(Exception e){e.printStackTrace ();} <qiap2  
} enepAu-="p  
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private void processErrorCode(int nErrorCode) N8Q{4c  
{ =!Cvu.~},  
System.err.println("Error Code : " + nErrorCode); 7!r`DZ"yF  
} `Hu;Gdj=  
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//停止文件下载 `-\JjMSQ1  
public void siteStop() )[Cm*Xxa$  
{ $e\R5Lu  
bStop = true; 0]W/88ut*u  
for(int i=0;i<nStartPos.length;i++) 4s2ex{$+MA  
fileSplitterFetch.splitterStop(); hkc_>F]Hx  
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} =jHy6)6w  
} NP/2gjp  
//负责部分文件的抓取 51usiOq  
**FileSplitterFetch.java PUo&>  
*/ . 2Q/D?a  
package NetFox; q+Q)IVaU81  
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import java.io.*; k9?+9bExXA  
import java.net.*; 40ZB;j$l  
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public class FileSplitterFetch extends Thread { Un+Jz ?Y  
(\ %y)  
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String sURL; //File URL +?'acn  
long nStartPos; //File Snippet Start Position v#G ^W  
long nEndPos; //File Snippet End Position $cCB%}  
int nThreadID; //Thread's ID a#$%xw  
boolean bDownOver = false; //Downing is over 'IszS!kY  
boolean bStop = false; //Stop identical mY9K
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FileAccessI fileAccessI = null; //File Access interface } 4^UVdz  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6dlPS{H#U  
{ zD|W3hL2&  
this.sURL = sURL; =jh:0Q<43+  
this.nStartPos = nStart; upKrr  
this.nEndPos = nEnd; aPgG+tu  
nThreadID = id;
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 RT9@&5>il  
} @e/dQ:Fb  
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06 1=pV$CJ  
public void run() QI<3N  
{ WDR!e2G  
while(nStartPos < nEndPos && !bStop) nrS_t y  
{ G}*B`m  
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try{ egvWPht'_  
URL url = new URL(sURL); 9IV WbJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I'h
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httpConnection.setRequestProperty("User-Agent","NetFox"); `$HO`d@0*R  
String sProperty = "bytes="+nStartPos+"-"; <NO~TBHF  
httpConnection.setRequestProperty("RANGE",sProperty);
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Utility.log(sProperty); /0(KKZ)  
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InputStream input = httpConnection.getInputStream(); K<(RVh  
//logResponseHead(httpConnection); [OSUARm v  
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byte[] b = new byte[1024]; ?0X.Ith^.  
int nRead; 9OBPFF  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &rubA  
{ d8I/7 ;F X  
nStartPos += fileAccessI.write(b,0,nRead); }z#8vE;  
//if(nThreadID == 1) 'cv/"26#  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \;<Y/sg  
} DSp@  
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Utility.log("Thread " + nThreadID + " is over!"); 3-5lO#&#  
bDownOver = true; oxZ(qfjS  
//nPos = fileAccessI.write (b,0,nRead); ~c"c9s+o  
} y-mmc}B>N  
catch(Exception e){e.printStackTrace ();} xC(PH?_  
} ^8)d8?}  
} *k -UQLJ  
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$9/r*@bu8d  
//打印回应的头信息 $}@ll^  
public void logResponseHead(HttpURLConnection con) Yc}b&  
{ v.MWO]L  
for(int i=1;;i++) 4
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{ vbp)/I-h  
String header=con.getHeaderFieldKey(i); )C[8#Q-:  
if(header!=null) ]Az >W*Y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); QG.FW;/L,  
Utility.log(header+" : "+con.getHeaderField(header)); HO>uS>+  
else !*;)]j  
break; AF !_!qc;  
} sXTO`W/  
} a/1{tDA  
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public void splitterStop() l;
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{ .?qS8:yA  
bStop = true; c<=1,TB"-_  
} 'JydaF~>  
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} Tym!7H2  
: SNp"|  
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/* y< 84Gw_  
**FileAccess.java 5o
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*//文件访问(定位，写) /dAIg1ra  
package NetFox; YL]x>7T~4t  
import java.io.*; /D12N'VaE  
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public class FileAccessI implements Serializable{ dFlx6H+R!0  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 &AzA0r&,  
RandomAccessFile oSavedFile; t0Uax-E(  
long nPos; Q["}U7j  
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public FileAccessI() throws IOException :Vg,[\I{  
{ +.=a R<Q  
this("",0); UX6-{ RP  
} 28-@Ga4  
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public FileAccessI(String sName,long nPos) throws IOException Lt)t}0  
{ vCJjZ%eO%D  
oSavedFile = new RandomAccessFile(sName,"rw"); :mij%nQ>$  
this.nPos = nPos; j$,`EBf`:<  
oSavedFile.seek(nPos); &wJ"9pQ~6E  
}
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public synchronized int write(byte[] b,int nStart,int nLen) MxYCMe4S[  
{ qz 'a.]{=  
int n = -1; Wl1%BN0>  
try{ 2axH8ONMu  
oSavedFile.write(b,nStart,nLen); c7'Pzb)'  
n = nLen; qhogcAvE  
} 9T\:ID=h  
catch(IOException e) SpkD  
{ 9%x[z%06  
e.printStackTrace (); \ZA%"F){  
} pJqayzV  
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return n; (+_Amw!W  
} 2a{eJ89f  
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} `H\^#Zu  
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: "UBeo<Z  
/* Cu}Rq!9i  
**SiteInfoBean.java TOQvZ?_
 
*/ SQ@@79A  
package NetFox; ]LD@I;(_  
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P
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public class SiteInfoBean { ex-
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private String sSiteURL; //Site's URL ~q<UE\H  
private String sFilePath; //Saved File's Path TygRG+G-  
private String sFileName; //Saved File's Name >8ePx,+!  
private int nSplitter; //Count of Splited Downloading File KNV$9&Z  
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x.'O_7c0:  
public SiteInfoBean() oYu5]ry  
{//nSplitter的缺省值为5 JMoWA0f  
//default value of nSplitter is 5 /0zk&g  
this("","","",5); ^K3{6}]  
} *'Ch(c:rtH  
7-)Y\D  
)=~1m85+5B  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) !x>P]j7A}Y  
{ TK'(\[E  
sSiteURL= sURL; t&ngOF  
sFilePath = sPath; E_FseR6  
sFileName = sName; TN&1C8xr  
this.nSplitter = nSpiltter; *NDzU%X8  
^58'*13ZL  
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} <MY_
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x}-rAr  
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public String getSSiteURL() t0/fF'GZD  
{ "xw2@jGpG  
return sSiteURL; Z[|(}9v?~  
} !IP[C?(nB  
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public void setSSiteURL(String value) /+%1Kq.hP  
{ Kg9REL@,s  
sSiteURL = value; k0%4&pU  
} O0wD"V^W  
}nuhLt1  
\07 s'W U  
public String getSFilePath() 8eL[,uw  
{ V"gnG](2l  
return sFilePath; &AC-?R|Dp  
} ;[&g`%-H<  
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7|\[ipVX:3  
public void setSFilePath(String value) `XQM)A  
{ 74QWGw`,  
sFilePath = value; n ,`!yw  
} iz>a0~(K  
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public String getSFileName() G.1pg]P!  
{ M++*AZ  
return sFileName; A-uEZj_RD=  
} r'-)@|  
Jo_h?{"L{  
?:~ `?  
public void setSFileName(String value) wC;N*0Th  
{ ]e 81O#t3  
sFileName = value; R:zjEhH)  
} R/U"]Rc  
tPc'#.  
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public int getNSplitter() ,Epg&)wC]  
{ mq>Ag  
return nSplitter; "@DCQ  
} W.{#Pg1Da  
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public void setNSplitter(int nCount) b>?X8)f2e  
{ 
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nSplitter = nCount; 76(&O  
} G ?H`9*y  
} OP{ d(~+  
-&y{8<bu4H  
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/* a'rN&*P  
**Utility.java ^!!@O91T  
*/ RR*<txdN  
package NetFox; n"$D/XJO  
0~Z2$`(  
=#SKN\4  
public class Utility { YB.r-c"Y  
ZmUS}  
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public Utility() =k'3rm*ld  
{ |&o%c/  
{])F%Q_#cD  
>?'cZTNk]  
} ~"iCx+pr  
/EA4-#uw  
//线程睡眠 =&< s*-l[  
public static void sleep(int nSecond) &CG3_s<2  
{ \@3i=!  
try{ +kmPQdO;*/  
Thread.sleep(nSecond); x/R|i%u-s  
} l0 rZril  
catch(Exception e) {eMu"<  
{ ma?$@]`k  
e.printStackTrace (); r. =_=V/t  
} lmgMR|v  
} T[*=7jnJQ  
7JQ5OC3  
//日志 UXnd~DA  
public static void log(String sMsg) z{7&=$  
{ *4dA(N\k"  
System.err.println(sMsg); p(:\)HP)R  
} 8(\Az5%  
[89#8|+  
rX)PN3TD  
public static void log(int sMsg) :DCj2"  
{ pTX{j=n!  
System.err.println(sMsg); o'?Y0Wt  
} 7_?:R2]n  
} HFB2ep7N  
ZOi8)Y~  
(G*--+Gn  
/* bBb$0HOF  
**TestMethod.java O sbY}*S  
*/ AM#VRRTU  
package NetFox; h)~KD%  
Yy@;
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public class TestMethod { VX2KE@  
1.4]T, `  
/#GX4&z  
public TestMethod() JnlM0jc]`  
{ ///xx/weblogic60b2_win.exe &>ii2% 4  
try{ !LVWggk1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Eo!1 WRruF  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); a]Bm0gdrO  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !=_:*U)-'  
fileFetch.start(); x}?y@.sn8  
} cO.U*UTmX  
catch(Exception e){e.printStackTrace ();} ~ b!mKyrZ  
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W7c(] tg.  
} J$%mG*Y(  
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+^iUY%pm  
public static void main(String[] args) By]XD~gcP  
{ kOmTji7  
new TestMethod(); U@@#f;&  
} Nq/,41  
} ,2qJXMg"=$  
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