http断点续传简单实现（java)

/* 8t--#sDy{0  
**SiteFileFetch.java [ArO$X3\  
*/ (,d/JnP  
package NetFox; JgxA^>|9;  
import java.io.*; VEr 6uvB  
import java.net.*; kkHTbn=!  
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public class SiteFileFetch extends Thread { QQSH +  
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SiteInfoBean siteInfoBean = null; //文件信息Bean n8 GF8a  
long[] nStartPos; //开始位置 3[,wM
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long[] nEndPos; //结束位置 K]%N-F>r  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 rS=tcBO  
long nFileLength; //文件长度 okVp\RC  
boolean bFirst = true; //是否第一次取文件 %zRiLcAT  
boolean bStop = false; //停止标志 }=xI3;7  
File tmpFile; //文件下载的临时信息 #%:`p9p.S  
DataOutputStream output; //输出到文件的输出流 KuU3DTS85Z  
.wM:YX'[G  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 65;|cmjv  
public SiteFileFetch(SiteInfoBean bean) throws IOException 4LJ]l:m  
{ 8Yo-~,Gb  
siteInfoBean = bean; Q*,6X*W!~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); u~ VswXc4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); zZ<ns+h  
if(tmpFile.exists ()) D l4d'&!  
{ 0P3j+? N%  
bFirst = false; wK2yt?  
read_nPos(); <[/PyNYK  
} ]VzqQ=U%  
else HDa~7wE  
{ xcAF  
nStartPos = new long[bean.getNSplitter()]; V@LN 1|  
nEndPos = new long[bean.getNSplitter()]; `WP@ZSC6  
} 0,;E.Py?.  
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} **Qe`}E:  
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public void run() Xs{:[vRW  
{ =W;
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//获得文件长度 TEH*@~P"  
//分割文件 )RpqZe/h4  
//实例FileSplitterFetch oqm  
//启动FileSplitterFetch线程 v@F|O8t:s  
//等待子线程返回 E_ o{c5N  
try{ J
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if(bFirst) Qx9>,e6+  
{ E`A<]dAoK  
nFileLength = getFileSize(); L"Qh_+  
if(nFileLength == -1) i5ajM,i/K  
{ P@^z:RS*{  
System.err.println("File Length is not known!"); ~uP r]#  
} ~ >&I^4  
else if(nFileLength == -2) E.
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{ :;" aUHU'  
System.err.println("File is not access!"); Ib_n'$5#z  
}  #a|6Q
8  
else []GthF  
{ Xtu:  
for(int i=0;i<nStartPos.length;i++) _)HD4,`  
{ c
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); [0mFy)6  
} ;zfQ3$@9  
for(int i=0;i<nEndPos.length-1;i++) i6meY$l  
{ N
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nEndPos = nStartPos[i+1]; O;"*_Xq(`  
} g:G%Ei~sF  
nEndPos[nEndPos.length-1] = nFileLength; "N?%mCPI  
} vjOG?-  
} %igFHh?  
lM@<_
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aF;]7i@  
//启动子线程 lWu9/r 1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; TnbGO;  
for(int i=0;i<nStartPos.length;i++) f:x9Y{Y  
{ <3i4NXnL2  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), I_"Hgx<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), -13P 2<i+  
nStartPos,nEndPos,i); WHpUjyBP  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); PK:o}IWn~x  
fileSplitterFetch.start(); 3p?<iVE  
} =j'J !M  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r`&2-]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); vF*^xhh  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0?J|C6XM#4  
nEndPos = " + nFileLength); ? 6yF{!F*  
// fileSplitterFetch[nPos.length-1].start(); 0)6i~MglY  
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Z@>=&  
//等待子线程结束 7G<KrKal  
//int count = 0; I]uOMWZs  
//是否结束while循环 + d+hvwEM  
boolean breakWhile = false; 5
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while(!bStop) Z1)jRE2dl  
{ v&[X&Hu[  
write_nPos(); F#!@}K8  
Utility.sleep(500); gL[1wM%?  
breakWhile = true; XEvGhy#  
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for(int i=0;i<nStartPos.length;i++) v -|P_O&z  
{ %-1BA*J`|  
if(!fileSplitterFetch.bDownOver) t?du+:  
{ hX>VVeIZ  
breakWhile = false; ${E[pT  
break; 0gwm gc/#  
} %h/#^esi  
}
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if(breakWhile) 2$SofG6D}  
break; ]2aYi9)  
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g "K#&  
//count++; ~7,2N.vO2  
//if(count>4) azR;*j8Q'  
// siteStop(); QKUBh-QFK  
} uK4'n+_>\  
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System.err.println("文件下载结束！");
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} M<#)D  
catch(Exception e){e.printStackTrace ();} q5'yD;[hE  
} `lu"yF  
8XS{6<  
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//获得文件长度 E1{
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public long getFileSize() H/p-YtY  
{ 3j=%De  
int nFileLength = -1; \CJx=[3(  
try{ =jV%O$Fx  
URL url = new URL(siteInfoBean.getSSiteURL()); f'zU^/$rf  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); R[>;_}5">  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7q2"b?|h  
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int responseCode=httpConnection.getResponseCode(); ]9KQP-p'  
if(responseCode>=400) cAKoPU>U  
{ v0hfY   
processErrorCode(responseCode); w.T=Lzp  
return -2; //-2 represent access is error .j:.WnW  
} @ (u?=x;  
},Y; (n'  
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=  
String sHeader; )v!lPpe8  
%!HnGwv-  
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for(int i=1;;i++) "`W1yk5x  
{ |U#w?eE=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); RaM#@D7  
//Utility.log(in.readLine()); 3w<j:\i  
sHeader=httpConnection.getHeaderFieldKey(i); ,SJK  
if(sHeader!=null) zI2KIXcc  
{ yhkQFB%gv  
if(sHeader.equals("Content-Length")) @aiLGwh  
{ rs 1*H  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); "k6IV&0 3x  
break; R26tQbwE  
} "$V8y  
} &x0TnW"g  
else x@ s`;qz  
break; n6!Ihip$  
} ssr)f8R#,#  
} X!+Mgh6  
catch(IOException e){e.printStackTrace ();} 5%Fn^u:  
catch(Exception e){e.printStackTrace ();} ,5A>:2 zs  
"{ QHWZ  
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Utility.log(nFileLength); N>}K+M>  
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return nFileLength; YqY6\mo  
} jC Kt;lj  
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i[t=@^|  
//保存下载信息（文件指针位置） @+CSY-g$  
private void write_nPos() kO3k|6f=  
{ E_'n4@}Cx  
try{ 3@cJ=  
output = new DataOutputStream(new FileOutputStream(tmpFile)); M%5$-;6~_  
output.writeInt(nStartPos.length); g7U:A0Z  
for(int i=0;i<nStartPos.length;i++) o4[2`mT  
{ :{xN33@6\X  
// output.writeLong(nPos); MMA@J  
output.writeLong(fileSplitterFetch.nStartPos); ;\*Od?1  
output.writeLong(fileSplitterFetch.nEndPos); ,@>rubUz  
} HsgTHe  
output.close(); ^9*|_\3N  
} 9-E>n)  
catch(IOException e){e.printStackTrace ();} UQf>5g  
catch(Exception e){e.printStackTrace ();} QV H'06"{  
} *UL|{_)c
 
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//读取保存的下载信息（文件指针位置） kzVI:  
private void read_nPos() U_{JM`JY  
{ ge {4;,0=  
try{ U)w|GrxX  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 5G]#yb74  
int nCount = input.readInt(); /L|}Y242  
nStartPos = new long[nCount]; <9@]|  
nEndPos = new long[nCount]; +#JhhW Zj(  
for(int i=0;i<nStartPos.length;i++) vBn=bb'W  
{ SQKY;p  
nStartPos = input.readLong(); &G,o guo  
nEndPos = input.readLong(); 6% y)  
} / ?[gB:s  
input.close(); wCTR-pL^  
} iBiA0 W  
catch(IOException e){e.printStackTrace ();} ;?lM|kK  
catch(Exception e){e.printStackTrace ();} F",abp!  
} 9MzkG87J  
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private void processErrorCode(int nErrorCode)
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{ ^R'!\m|FR  
System.err.println("Error Code : " + nErrorCode); XsN#<"f;i  
} ccR
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//停止文件下载 6-X?uaY)os  
public void siteStop() 
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{ Dw ;vDK  
bStop = true; oplA'Jgnv  
for(int i=0;i<nStartPos.length;i++) "A1yqK  
fileSplitterFetch.splitterStop(); U}wq~fD  
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} v|RaB  
} hic$13KuP  
//负责部分文件的抓取 5GFnfc}  
**FileSplitterFetch.java XK/@!ud"`  
*/ \\G6c4fC  
package NetFox; ,M h/3DPgE  
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import java.io.*; Sy
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import java.net.*; LLHOWD C(2  
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public class FileSplitterFetch extends Thread { +\M
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String sURL; //File URL Mh.eAM8_  
long nStartPos; //File Snippet Start Position P~ZV:Of  
long nEndPos; //File Snippet End Position Jo(}#_y?  
int nThreadID; //Thread's ID wX
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boolean bDownOver = false; //Downing is over KC-aLq/  
boolean bStop = false; //Stop identical kGqf@ I+  
FileAccessI fileAccessI = null; //File Access interface WI!z92qq[  
[k=9 +0p  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Tc(v\|F,  
{ r=||sZs  
this.sURL = sURL; BBJ]>lQ  
this.nStartPos = nStart; :::f,aCAu  
this.nEndPos = nEnd; o4f9EJY  
nThreadID = id; molowPI  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 hJ*E"{xs  
} ~S>ba']  
![!b^:f  
#R PB;#{  
public void run() L0V

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{ wP':B AQ4U  
while(nStartPos < nEndPos && !bStop) 2^ZPO4|  
{ a[cH@7W.#  
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try{ =pOY+S|  
URL url = new URL(sURL); *K.7Zf0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); KR(ftG'  
httpConnection.setRequestProperty("User-Agent","NetFox"); d>98 E9  
String sProperty = "bytes="+nStartPos+"-"; BF[?* b  
httpConnection.setRequestProperty("RANGE",sProperty); <\~#\A=;  
Utility.log(sProperty); B@vH1T  
,:4w$!;  
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InputStream input = httpConnection.getInputStream(); knzED~v@(  
//logResponseHead(httpConnection);
)-"L4TC)  
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byte[] b = new byte[1024]; :{uUc  
int nRead; RX\O'Zwlj  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @N{Ht)1r  
{ |+~2sbM  
nStartPos += fileAccessI.write(b,0,nRead); 3i}B\ {  
//if(nThreadID == 1) |3@Pt>Ikl  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _-\{k
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}
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T2; 
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Utility.log("Thread " + nThreadID + " is over!"); B"zg85 e  
bDownOver = true; 3 v$
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//nPos = fileAccessI.write (b,0,nRead); #7T={mh  
} J5IJy3d  
catch(Exception e){e.printStackTrace ();} u.Yb#?  
} s?#lhI  
} X(z-?6N4  
L/LNX{|  
l>?vjy65  
//打印回应的头信息 EoCwS  
public void logResponseHead(HttpURLConnection con) }B/xQsTx-  
{ {*$J&{6V  
for(int i=1;;i++) HKw:fGt/o^  
{ M':.b+xN  
String header=con.getHeaderFieldKey(i); ZSt ww{Z
 
if(header!=null) B8Zd#.6]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *
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Utility.log(header+" : "+con.getHeaderField(header)); ~At.V+  
else 'oL[rO~j  
break; Li^!OHro.  
} c6)zx b  
} o:\a  
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/k"P4\P`+Q  
public void splitterStop() K!gFD
  
{ ^v|!(h\ZC  
bStop = true; Hv*O9!cC  
} 'Pu;]sC  
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} b
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/* hI{Yg$H1  
**FileAccess.java 
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*//文件访问(定位，写) xyz86r ^u  
package NetFox; v72 dE  
import java.io.*; 7Z3qaXPH  
:|3C-+[  
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public class FileAccessI implements Serializable{ r1a
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1dsxqN(:  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 V%=t2+  
RandomAccessFile oSavedFile;  B4ze$#  
long nPos; n#/m7  
our5k
 
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public FileAccessI() throws IOException 9V\`{(R  
{ 0O4mA&&!oK  
this("",0); iNSJO
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} V'/%)oU\"  
kyB]fmS  
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public FileAccessI(String sName,long nPos) throws IOException ^]gl#&"D  
{ {'kL]qLg  
oSavedFile = new RandomAccessFile(sName,"rw"); pBkPn+@  
this.nPos = nPos; =^vUb  
oSavedFile.seek(nPos); 3)\qts5  
} _4Pi>  
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public synchronized int write(byte[] b,int nStart,int nLen) U$bM:d  
{ )wd~639U  
int n = -1; +ETw:i9!?  
try{ C\D4C]/8  
oSavedFile.write(b,nStart,nLen); 0fU>L^P_?  
n = nLen; =x>k:l~s  
} a@J:*W  
catch(IOException e) B.#0kjA}  
{ u*`GIRfWT  
e.printStackTrace (); 9t1_"{'N1  
} 74#@F{w  
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return n; {*9i}w|2  
} $*R9LPpk+  
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} t+ ]+Gn  
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/* &ii =$4"R  
**SiteInfoBean.java ^pa).B.`T  
*/ =`H(`2  
package NetFox; jN0v<_PJED  
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public class SiteInfoBean { "o^zOU  
5H5Kt9DoW  
]3'd/v@fT  
private String sSiteURL; //Site's URL M(f'qFY=K  
private String sFilePath; //Saved File's Path QNFrkel  
private String sFileName; //Saved File's Name VuW19-G  
private int nSplitter; //Count of Splited Downloading File ~Y[1Me  
QCw<* Id+  
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public SiteInfoBean() U"]i.J1  
{//nSplitter的缺省值为5 [-ecKPx  
//default value of nSplitter is 5 v( B4Bz2  
this("","","",5); o++Hdvai  
} C7PiuL?  
C
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 6"(&l
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{ ~@;7}Aag  
sSiteURL= sURL; +6*I9R  
sFilePath = sPath; IYPLitT  
sFileName = sName; w=$_',5#Z  
this.nSplitter = nSpiltter; RI=B(0A  
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}f}&|Vap  
} l-rnDl  
Jo0x/+?,+  
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public String getSSiteURL() &Is%I<'o  
{ vI@8DWs  
return sSiteURL; we9AB_y  
} I1,?qr"Zr  
79DC]48M  
rIb{=';  
public void setSSiteURL(String value) yS""*8/  
{ '4rgIs3=x"  
sSiteURL = value; +#no$m.bH  
} 5`Bb0=j  
;D:v@I$I  
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public String getSFilePath() 4]GyuY  
{ ZSNg^)cN  
return sFilePath; Z"jo xZ  
} N.?Wev{  
~nQb;Bdh%  
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public void setSFilePath(String value) ,J
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{ :lAR;[WFS  
sFilePath = value; (hoqLL\}k  
} xjYFTb}!  
;z68`P-  
<#UvLll  
public String getSFileName() `t -3(>P  
{ 7o<RvM  
return sFileName; ;/
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} ~U|te_l  
@WmB0cc_  
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public void setSFileName(String value) X {$gdz8S9  
{ 1X5\VY>S`h  
sFileName = value; cQny)2k*x  
} /[O
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OX"`VE  
>&R|t_ypw  
public int getNSplitter() .JqIAC~  
{ .o>QBYpTw/  
return nSplitter;
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} \0$?r4A  
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public void setNSplitter(int nCount) H4N==o  
{ = U5)m  
nSplitter = nCount; ?2M15Q  
} d={}a,3?  
} V;!D:N8<  
^6`U0|5mRX  
e|I5Nx2)  
/* ,RZktWW_  
**Utility.java R?W8l5CIk  
*/ j{vzCRa>8  
package NetFox; Q|>y2g!  
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public class Utility { mXr)lA  
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public Utility() 'BC-'Ot  
{ Y9WH%  
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} ()rDM@  
| 8AH_Fk  
//线程睡眠 AA66^/t  
public static void sleep(int nSecond) p7*\]HyE)  
{ vq{:=:5'P  
try{ R1nctA:  
Thread.sleep(nSecond); 8wBns)wy@  
} |^1eL I  
catch(Exception e) qRUz;M4  
{ yoH6g?!O  
e.printStackTrace (); 4avM:h  
} X#J[Nn>  
} eRGip2^cq+  
cX*^PSM  
//日志 ,YoIn  
public static void log(String sMsg) NYCkYI  
{ ."R 2^`  
System.err.println(sMsg); W46sKD;\^W  
}
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k: {$M yK  
public static void log(int sMsg) ''Hq-Ng  
{ 6ul34\;  
System.err.println(sMsg); pY2nv/  
} MG~^>  
}  I{E10;  
y]Y)?])  
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/* y]/{W}D  
**TestMethod.java ]`MRH[{  
*/ { "/@,!9rJ  
package NetFox; )P$
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!u^(<.xJ   
public class TestMethod { k8h$#@^  
?0%lB=qQ  
39OZZaWL  
public TestMethod() *P_TG"^{W  
{ ///xx/weblogic60b2_win.exe -X |G  
try{ 43/|[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); x>t:&Y M  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `0sa94H1[  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ;a68>5Lm*  
fileFetch.start(); 4Q$\hO3b  
} F Hv|6zUX  
catch(Exception e){e.printStackTrace ();} BqR8%F  
xbIxtZm  
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} }C)  
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public static void main(String[] args) -8-Aqh8|  
{ ^7(zoUn:  
new TestMethod(); aeSXHd?+(  
} 4Jw0m#UN1  
} t.]oLG22r  
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