http断点续传简单实现（java)

/* SnE(o)Q  
**SiteFileFetch.java R%Q@  
*/ b~'"^ Bts*  
package NetFox; V,q](bg  
import java.io.*; Pa{%\dsv  
import java.net.*; Sx?ua<`:d  
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public class SiteFileFetch extends Thread { <\NY<QIwFw  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 'NX```U0  
long[] nStartPos; //开始位置 .q9 $\wM/  
long[] nEndPos; //结束位置 /LO-HnJ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 o Z%9_$Z  
long nFileLength; //文件长度 a
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boolean bFirst = true; //是否第一次取文件 D+>4AqG  
boolean bStop = false; //停止标志 R
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File tmpFile; //文件下载的临时信息 W#KpPDgZE  
DataOutputStream output; //输出到文件的输出流 JBJhG<J  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） kPVO?u
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public SiteFileFetch(SiteInfoBean bean) throws IOException LL2=&VK  
{ 8g&? Cc  
siteInfoBean = bean; -amBB7g  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Zrvz;p@~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !q9+9 *6  
if(tmpFile.exists ()) 2 dAB-d:k  
{ ~kZ G{  
bFirst = false; ~ vJ,`?  
read_nPos(); W7 Cc  
} c2&q*]?l;  
else <)u`~$n2  
{ R $&o*K`?  
nStartPos = new long[bean.getNSplitter()]; *Eo?k<:zPm  
nEndPos = new long[bean.getNSplitter()]; Pb?$t  
} Olh<,p+x  
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} c&AygqN  
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public void run() huJ&
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{ *QLI3B9V  
//获得文件长度 b*`lk2oMa/  
//分割文件 #7MUJY+ 9  
//实例FileSplitterFetch KTP8?Q"n0  
//启动FileSplitterFetch线程 c
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//等待子线程返回 `-3Ow[  
try{ %d?cP}V  
if(bFirst) .7l&1C)i  
{ a{R%#e\n  
nFileLength = getFileSize(); P%#<I}0C  
if(nFileLength == -1) EJsM(iG]~M  
{ vJ'2@f$  
System.err.println("File Length is not known!"); s;3={e.  
} QKr,g  
else if(nFileLength == -2) ^~3SSLS4"  
{ K?BOvDW"`  
System.err.println("File is not access!"); B]uc<`f  
} `[W[H(AjQ  
else P*I}yPeb  
{ h"_MA_]~  
for(int i=0;i<nStartPos.length;i++) dHv68*^\'  
{ BDR.AZ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8xccp4  
} i(>4wK!!  
for(int i=0;i<nEndPos.length-1;i++) ;*:Pw?'  
{ y#q?A,C@n
 
nEndPos = nStartPos[i+1]; b)=[
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} /+@p7FqlE  
nEndPos[nEndPos.length-1] = nFileLength; }Q=!Y>Tc  
} eA#;AQm  
} T3k#VNH  
4A_[PM  

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//启动子线程
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; b/C`Jp  
for(int i=0;i<nStartPos.length;i++) ~c %hWt  
{ kic/*v\6@  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), YgUvOyaQXf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4`!Z$kt  
nStartPos,nEndPos,i); Jo@|"cE=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); no< ^f]33  
fileSplitterFetch.start(); OH">b6>\  
} ?XA
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z yE `/J'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [3{W^WSOz  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]Bjyi[#bg  
nEndPos = " + nFileLength); bdQ_?S(  
// fileSplitterFetch[nPos.length-1].start(); d` jjGEj  
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//等待子线程结束 tE]
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//int count = 0; ">y%iE  
//是否结束while循环 cp#JBHO  
boolean breakWhile = false; A?-oL='  
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while(!bStop) bO'Sgc[]  
{ i`dCG[  
write_nPos(); =8; {\  
Utility.sleep(500); aC%m-m  
breakWhile = true; aVK3?y2  
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for(int i=0;i<nStartPos.length;i++) E ,|xJjh  
{ qoj$]   
if(!fileSplitterFetch.bDownOver) p;t
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{ 5[* qi?w=  
breakWhile = false; }Rz3<eON  
break; eC[$B99\  
} kH
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} Q4f/Z  
if(breakWhile) Hhari!RXC  
break; YN!>}  
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[&&1j@LQ*  
//count++; m0cP(  
//if(count>4) \H=&`?  
// siteStop(); !+L/Khw/C  
} iy14mh\ ~  
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System.err.println("文件下载结束！"); f"u%J/e&  
} k;w- E  
catch(Exception e){e.printStackTrace ();} .)<(Oj|4  
} j}~86JO+Cw  
$+>M{fg?  
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//获得文件长度 o[cV1G  
public long getFileSize() l,,>& F  
{ pBETA'fY  
int nFileLength = -1; }RwSp!}C  
try{ S%yd5<%_  
URL url = new URL(siteInfoBean.getSSiteURL()); DRc)iE>@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ; =X P&  
httpConnection.setRequestProperty("User-Agent","NetFox"); yjhf   
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int responseCode=httpConnection.getResponseCode(); .h>8@5/s  
if(responseCode>=400) IuNi
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{ )tl.
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processErrorCode(responseCode); +TQ47Zc  
return -2; //-2 represent access is error yp66{o  
} {3.r6ZwCn  
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String sHeader; brdmz}  
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for(int i=1;;i++) n(L\||#+  
{ ,=|ZB4HA  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); + j
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//Utility.log(in.readLine()); QoG cWJ  
sHeader=httpConnection.getHeaderFieldKey(i); 1;mW,l'`  
if(sHeader!=null) 8[J}CdS  
{ /ig:9R  
if(sHeader.equals("Content-Length")) []A%<EI7  
{ /k<WNZM  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 4Rvf  
break; #@"<:!?z  
} %7gkNa  
} ,{LG4qvP  
else av$/Om:  
break; h3Q21D'f  
} [&nh5|f  
} DBCK2PlJ  
catch(IOException e){e.printStackTrace ();} "Q?k'^@  
catch(Exception e){e.printStackTrace ();} l"2OP6d  
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Utility.log(nFileLength); I;Bjfv5  
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return nFileLength; JM\m)RH0  
} ^1L>l9F  
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//保存下载信息（文件指针位置） E[bd@[N 8  
private void write_nPos() Q~j`YmR|  
{ XLH+C ]pfr  
try{ vsr[ur[eP  
output = new DataOutputStream(new FileOutputStream(tmpFile)); tc!wLnhG  
output.writeInt(nStartPos.length); m/qbRk68s  
for(int i=0;i<nStartPos.length;i++) YJl("MZ  
{ 61jI  
// output.writeLong(nPos); ")!,ZD  
output.writeLong(fileSplitterFetch.nStartPos); #*g5u{k'P  
output.writeLong(fileSplitterFetch.nEndPos); I<8sI%,s  
} |7}CQU  
output.close(); ZG du|  
} >+ 4huRb  
catch(IOException e){e.printStackTrace ();} gF5a5T,  
catch(Exception e){e.printStackTrace ();} Tp9-niW  
} %
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//读取保存的下载信息（文件指针位置） bLd#xXl  
private void read_nPos() X0M1(BJgGo  
{ <1.A=_ M  
try{ ulER1\W  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _Jt 2YZdA  
int nCount = input.readInt(); hwIMn33  
nStartPos = new long[nCount]; A6pj
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nEndPos = new long[nCount]; LI6hEcM=  
for(int i=0;i<nStartPos.length;i++) Wf&W^Q  
{ sPb=82~z  
nStartPos = input.readLong(); `QUy;%+  
nEndPos = input.readLong(); 4)<~4 '  
} Zt&6Ua[Y}  
input.close(); @bnG:np  
} !DI{:I_h(  
catch(IOException e){e.printStackTrace ();} z ly unJD(  
catch(Exception e){e.printStackTrace ();} wj1{M.EF\  
} pIKSs<IP  
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private void processErrorCode(int nErrorCode) $
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{ zBP>jM(8  
System.err.println("Error Code : " + nErrorCode); |-CnT:|o  
} "/nNM{^  
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//停止文件下载 $Tb G+Eb8  
public void siteStop() )5.C]4jol  
{ L:k9#6  
bStop = true; &%_& 8DkG  
for(int i=0;i<nStartPos.length;i++) @j4U^"_QB  
fileSplitterFetch.splitterStop(); T1r3=Y4  
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} k~|-gfFP  
} D K
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//负责部分文件的抓取 (}
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**FileSplitterFetch.java F|HJH"2*&q  
*/
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package NetFox; I6s3+x;O  
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import java.io.*; Y2[A2Uy$ef  
import java.net.*; ?*oKX  
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public class FileSplitterFetch extends Thread { C(id=F  
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String sURL; //File URL j}AFE  
long nStartPos; //File Snippet Start Position 'vbc#_;  
long nEndPos; //File Snippet End Position Dr~=o%  
int nThreadID; //Thread's ID zP;cTF(C  
boolean bDownOver = false; //Downing is over R i'L  
boolean bStop = false; //Stop identical ZJjTzEV%^B  
FileAccessI fileAccessI = null; //File Access interface hHPs&EA.p  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException LjH*rjS4  
{ 033T>qY  
this.sURL = sURL; N<L`c/  
this.nStartPos = nStart; !gmH$1w  
this.nEndPos = nEnd; 7HHysNB"w  
nThreadID = id; B<~U3b  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 DS-fjH\  
} P\&! ]  
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public void run() )kJH5/  
{ & ``d  
while(nStartPos < nEndPos && !bStop) 4W#
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{ D)brPMS:o  
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try{ jkF8\dR  
URL url = new URL(sURL); :EtMH(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '>v^6iS  
httpConnection.setRequestProperty("User-Agent","NetFox"); )!Bd6-  
String sProperty = "bytes="+nStartPos+"-"; D5an\gE  
httpConnection.setRequestProperty("RANGE",sProperty); X{g%kf,D=  
Utility.log(sProperty); 2F8|I7R  

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InputStream input = httpConnection.getInputStream(); '?Jxt:<  
//logResponseHead(httpConnection); f2,1<^{  
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byte[] b = new byte[1024]; o_Si mJFK  
int nRead; ?K@t0a
 
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) dtAbc7
 
{ SxjCwX">  
nStartPos += fileAccessI.write(b,0,nRead); M- 0i7%  
//if(nThreadID == 1) )=
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &-1.
/?  
} @wq#>bm  
S }>n1F_
 
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Utility.log("Thread " + nThreadID + " is over!"); 9Z6C8Jv  
bDownOver = true; dP>w/$C}  
//nPos = fileAccessI.write (b,0,nRead); IF@HzT;Q  
} Lz\UZeq  
catch(Exception e){e.printStackTrace ();} L;QY<b  
} G5tday~3  
} !?[oIQ)h  
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//打印回应的头信息 M3z
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public void logResponseHead(HttpURLConnection con) D^Ys)- d  
{ t!_x(u  
for(int i=1;;i++) Be}$I_95\P  
{ o/
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String header=con.getHeaderFieldKey(i); > 4oY3wk8  
if(header!=null) 1zktU.SZ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); {?{U,&  
Utility.log(header+" : "+con.getHeaderField(header)); -n*;W9  
else c0 WFlj9b  
break; @1R8-aa-r  
} w.N,)]h  
} }xlKonk  
+@VYs*&&  
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public void splitterStop() :o"8MZp  
{ dZGbC9  
bStop = true; MF[z-7  
} jK8'T_Pah  
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} d \>2  
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/* '9J|=z9.  
**FileAccess.java Xev54!619  
*//文件访问(定位，写) 2@vj!U8  
package NetFox; W>spz~w%j  
import java.io.*; eFTX6XB:i  
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@<_`2eW'/R  
public class FileAccessI implements Serializable{ =z:U~D  
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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 NE"jh_m-
 
RandomAccessFile oSavedFile; oj}"H>tTp  
long nPos; eSl-9 ^  
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public FileAccessI() throws IOException (OQ?<'Qa  
{ sXl ??UGe  
this("",0); 'nK~'P
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} l9{#sas  
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public FileAccessI(String sName,long nPos) throws IOException  d^39
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{ ]Qi,j#X  
oSavedFile = new RandomAccessFile(sName,"rw"); =:h3w#_c  
this.nPos = nPos; R V!o4"\]  
oSavedFile.seek(nPos); 2w?G.pO#  
} dmR3Y.\jd  
] mj v;C  
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public synchronized int write(byte[] b,int nStart,int nLen) "E*8h/4u  
{  }sMW3'V  
int n = -1; i#,1iVSG  
try{ Q2C
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oSavedFile.write(b,nStart,nLen); !Y;<:zx5  
n = nLen; "+iAd.qd  
} {Iy7.c8S  
catch(IOException e) ^i<}]c_|f  
{ ;mO,3dV  
e.printStackTrace (); L(WOet('  
} _g6m=N4  
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return n; Ugi5OKdj7)  
} RT"O;P  
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} i+~QDo(Pi  
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/* 
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**SiteInfoBean.java ;]&-MFv#  
*/ =|y|P80w  
package NetFox; bNvAyKc-  
?^3B3qqh9  
'TEyP56  
public class SiteInfoBean { R}J-nJlb  
'yNPhI  
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private String sSiteURL; //Site's URL 0|2%# E  
private String sFilePath; //Saved File's Path i X/tt  
private String sFileName; //Saved File's Name ",Wf uz  
private int nSplitter; //Count of Splited Downloading File Pi%tsKk%  
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public SiteInfoBean() +)-d_K.(k  
{//nSplitter的缺省值为5 -Uf4v6A  
//default value of nSplitter is 5 Tcs3>lJ}  
this("","","",5); v_-ls"l  
} >5i?JUZ  
+-HE'4mo  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 3#9M2O\T  
{ ~'f8L#[M  
sSiteURL= sURL; 3@X|Gs'_S  
sFilePath = sPath; %)IrXz>Zh  
sFileName = sName; mcMb*?]  
this.nSplitter = nSpiltter; Z90Fcp:R  
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} u'@Ely  
9}whWh  
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public String getSSiteURL() wU0K3qZL
 
{ Ak|b0l>^  
return sSiteURL; =n }Yqny  
} f)tc4iV  
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public void setSSiteURL(String value) w?;b7i  
{ 1OPfRDn.bk  
sSiteURL = value; 8g5.7{ky  
} !'PlDGD  
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public String getSFilePath() Qy%xL9  
{ sVD([`Nmc  
return sFilePath; j}RM.C\7  
} akrCs&Kka5  
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public void setSFilePath(String value) 5|m9:Hv[#  
{ gDc]^K4>  
sFilePath = value; %9YA^ri  
} (lWKy9eTy`  
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2_Jb9:/X  
public String getSFileName() DD6'M U4  
{ %((cFQ9  
return sFileName; T=yCN#cqQ`  
} i\Q":4  
@YrGyq  
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public void setSFileName(String value) j~$)c)h"  
{ c8tP+O9  
sFileName = value; p(7c33SyF  
} x[a'(5PwY  
lzI/\%  
" xxXZGUp  
public int getNSplitter() 4= $!_,.  
{ tpz=}q  
return nSplitter; ^X(_zinN"  
} [sptU3,2U  
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public void setNSplitter(int nCount) `bi k/o=%  
{ 2q$X>ImI$  
nSplitter = nCount; :!hk~#yvJ9  
} DMRs}Yz6  
} vy:
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/* ^zkd{ov  
**Utility.java `O jvt-5}E  
*/ I@c0N*(  
package NetFox; X[Y#+z4  
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public class Utility { ~JT lPU'  
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public Utility() rcpvH}N:  
{ /.f!  
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]#+5)[N$>  
} ;
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M`q#,Y?3^I  
//线程睡眠 uJ7,rq  
public static void sleep(int nSecond) :nTkg[49pJ  
{ )/i4YL
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try{ mr
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Thread.sleep(nSecond); [29$~.m$Y  
} CcbWW4 )  
catch(Exception e) !/[AQ{**T!  
{ .Pqj6Ko9  
e.printStackTrace (); Iy-u`S  
} \y<+Fac1S  
} pq@$&G  
UYlJO{|a  
//日志 ]IL3$eR  
public static void log(String sMsg) "P9wT)J_  
{ xU:PhhS  
System.err.println(sMsg); :s
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} FP0<-9DO  
Y'\3ux0]4'  
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public static void log(int sMsg) mq>*W'M  
{ -_:
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System.err.println(sMsg); YL_!#<k@  
} 5Xla_@WLW  
} oM m/!Dc  
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/* }P7xdQ6  
**TestMethod.java +*]SP@|IYI  
*/ R?i-"JhW  
package NetFox; 8'>.#vyMGv  

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public class TestMethod { t%ou1&SO  
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public TestMethod() *T1L)Cp  
{ ///xx/weblogic60b2_win.exe P1vF{e  
try{ k B$lkl\C  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); WllCcD1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Zm?G'06  
SiteFileFetch fileFetch = new SiteFileFetch(bean); JT}dor  
fileFetch.start(); OqUE4.vIP  
} GhaAvyN  
catch(Exception e){e.printStackTrace ();} K.c6Rg  
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o
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} ,5%aP%  
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public static void main(String[] args) rQAbN
6  
{ ]&; G\9$y  
new TestMethod(); (*c`<|)  
} t2`X!`  
} xNkwTDN5  
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