http断点续传简单实现（java)

/* oVY_|UujG  
**SiteFileFetch.java `Af5%m
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*/ LKYcE;n  
package NetFox; N[kl3h%q  
import java.io.*; l4\!J/df  
import java.net.*; A}_0iwG  
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public class SiteFileFetch extends Thread { .@@&q4=&  
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SiteInfoBean siteInfoBean = null; //文件信息Bean (1)b> 6  
long[] nStartPos; //开始位置 .7> g8  
long[] nEndPos; //结束位置 B]:?4Ov  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~9c jc  
long nFileLength; //文件长度 lf_q6y  
boolean bFirst = true; //是否第一次取文件 R{q<V uN  
boolean bStop = false; //停止标志 yZ,S$tSR  
File tmpFile; //文件下载的临时信息 `_(N(dm  
DataOutputStream output; //输出到文件的输出流 rAS2qt  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） >Y;[+#
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public SiteFileFetch(SiteInfoBean bean) throws IOException spma\,o  
{ =4K:l}}  
siteInfoBean = bean; p+16*f9,^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); QG5)mIJ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); [uFv_G{H  
if(tmpFile.exists ()) + De-U.  
{ jm,:jkr  
bFirst = false; v-}B T+  
read_nPos(); 6o~g3{O
w  
} n\u3$nGL1`  
else n1rJ^q-G  
{ ;TboS-Y  
nStartPos = new long[bean.getNSplitter()]; Xuj=V?5  
nEndPos = new long[bean.getNSplitter()]; 6yXN7L==x  
} +5H1n(6)  
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} ;Ngu(es6  
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public void run() :xC1Ka%~  
{ 4_ kg/  
//获得文件长度 #xt-65^  
//分割文件 4\m#:fj %  
//实例FileSplitterFetch +d=8/3O%  
//启动FileSplitterFetch线程 hlFvm$P`M  
//等待子线程返回 nS]Ih0(K  
try{ O@-(fyG  
if(bFirst) OD).kP}s^  
{ e]D TK*W~  
nFileLength = getFileSize(); x,#?  
if(nFileLength == -1) T5>'q;jM  
{ ,AyQCUz{*?  
System.err.println("File Length is not known!"); bkIQ?cl<at  
} (~]0)J  
else if(nFileLength == -2) sNsWz.DLT#  
{ `$ZBIe/u  
System.err.println("File is not access!"); OVEQ^\Q5D  
} s\q m  
else _"lW  
{ \{a 64  
for(int i=0;i<nStartPos.length;i++) @MfZP~T+  
{ f# sDG  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); )J1xO^tE  
} "/{H=X3was  
for(int i=0;i<nEndPos.length-1;i++) I?KGb:]|  
{ ]".SW5b_  
nEndPos = nStartPos[i+1]; NH!x6p]n  
} 3W55m@w  
nEndPos[nEndPos.length-1] = nFileLength; 0E/16@6=  
} kNv/L$oG  
} YeV
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//启动子线程 eI=:z/p
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; PPj%
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for(int i=0;i<nStartPos.length;i++) u*8x.UE8C0  
{ >5j&Q#Bu  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V~S(cO[vj  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 1_5]3+r_U-  
nStartPos,nEndPos,i); M+Eg{^ q`  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @K}Bll.E  
fileSplitterFetch.start(); IAb-O  
} RpU.v `
 
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), vec4R )S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); qw}. QwPT  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", [
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nEndPos = " + nFileLength); Lo5CVl
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// fileSplitterFetch[nPos.length-1].start(); Sj
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}/}eZCa
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//等待子线程结束 ~o8x3`CoF  
//int count = 0; jl,
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//是否结束while循环 $B?IE#7S4  
boolean breakWhile = false; =|
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#EIcP=1m4  
while(!bStop) V7$-4%NL  
{ =iE)vY,?"}  
write_nPos(); jF|LPWl  
Utility.sleep(500); )*Rr5l /l  
breakWhile = true; /H :Bu  
~A,(D-  
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for(int i=0;i<nStartPos.length;i++) +p0Y*.  
{ -e_B  
if(!fileSplitterFetch.bDownOver) QHw{@*  
{ #hh7fE'9  
breakWhile = false; xH{V.n&v  
break; BD&AtOj[,  
} #-K,,"  
} NU.YL1  
if(breakWhile) =[IKwmCX  
break; LqoH]AcN  

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//count++; RgLkAHA  
//if(count>4) 1owe'7\J  
// siteStop(); r,cK#!<%  
} R6qC0@*  
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System.err.println("文件下载结束！"); 2>Sr04Pt  
} uEDvdd#V.  
catch(Exception e){e.printStackTrace ();} q.v_?X<_  
} )/uCdSDIc  
HQ`A.E2  
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//获得文件长度 MTeCmFe0;  
public long getFileSize() 4/E>k <MA  
{ jn#Ok@tZ  
int nFileLength = -1; x}H%NzR  
try{ zH1ChgF=}  
URL url = new URL(siteInfoBean.getSSiteURL());  b~Oc:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F/0x`l  
httpConnection.setRequestProperty("User-Agent","NetFox"); H?)?(t7@  
@po|07  
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int responseCode=httpConnection.getResponseCode(); l8By2{pN  
if(responseCode>=400) tk'3Q1L  
{ ~A-VgBbU>_  
processErrorCode(responseCode); VMV~K7%0  
return -2; //-2 represent access is error _`q ei0  
} Nj;G%KAP  
J)_IfbY  
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String sHeader; @4%x7%+[c  
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for(int i=1;;i++) XOd  
{ `&qeSEs\  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); BZ>,Qh!J  
//Utility.log(in.readLine()); y2NVx!?n  
sHeader=httpConnection.getHeaderFieldKey(i); K 6HH_T  
if(sHeader!=null) pQOT\- bD  
{ R*z:+p}oHy  
if(sHeader.equals("Content-Length")) \C;F5AO  
{ ulxy 4] h  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =1h> N/VJ  
break; h|Udw3N1L  
} j#JE4(&  
} Gt5'-Hyo  
else yB,{:kq7D  
break; "xY]&  
} %eLf6|1x  
} ">NPp\t>/Z  
catch(IOException e){e.printStackTrace ();} Nlfz'_0M  
catch(Exception e){e.printStackTrace ();} a0[Mx 4  
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Utility.log(nFileLength); ?&GV~DYxA  
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return nFileLength; x\2N @*I:  
} 6o^sQ(]  
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//保存下载信息（文件指针位置） pxi/ ]6pw  
private void write_nPos() TWAt
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{ 
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try{ 3tIno!|  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )#_:5^1  
output.writeInt(nStartPos.length); &Eqa y'  
for(int i=0;i<nStartPos.length;i++) u+/1ryp  
{ |FrZ,(
\  
// output.writeLong(nPos); &[iunJv:eq  
output.writeLong(fileSplitterFetch.nStartPos); 1>e%(k2w%  
output.writeLong(fileSplitterFetch.nEndPos); A%
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} g_F-PT>($  
output.close(); Ci?A4q$.  
} q'~F6$kv5  
catch(IOException e){e.printStackTrace ();} Bfz]PN78.G  
catch(Exception e){e.printStackTrace ();} e#jkp'  
} ww(.   
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//读取保存的下载信息（文件指针位置） Af%#&r7W  
private void read_nPos() |<Gq^3 2  
{ y
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try{ TB  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); L-\o zp  
int nCount = input.readInt(); {s/u[T_D2  
nStartPos = new long[nCount]; E A8>{}Z*  
nEndPos = new long[nCount]; 5EqC.g.  
for(int i=0;i<nStartPos.length;i++) Jg\1(ix  
{ `tb@x ^  
nStartPos = input.readLong(); +rA:/!b)Y  
nEndPos = input.readLong(); 'z.: e+Q_  
} DeTD.)pS  
input.close(); Kc[Y .CH  
} tQ > IJ  
catch(IOException e){e.printStackTrace ();} !tL&Ktoj  
catch(Exception e){e.printStackTrace ();} 7w]NG`7  
} h-`*S&mZ  
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private void processErrorCode(int nErrorCode) 31@m36? X  
{ Mm'q4DV^  
System.err.println("Error Code : " + nErrorCode); ?6[X=GeUs  
} 5QoU&Hv  
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//停止文件下载 DoYzTSWx  
public void siteStop() ,{_;q:  
{ wK[Xm'QTPJ  
bStop = true; DKGZm<G>  
for(int i=0;i<nStartPos.length;i++) B1C"F-2d  
fileSplitterFetch.splitterStop(); zu8l2(N  
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} )]?"
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} :',Q6j(s  
//负责部分文件的抓取 EFYyr f@  
**FileSplitterFetch.java
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*/ V9"?}cR/W;  
package NetFox; />i~No#Xm  
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-#ta/*TT:  
import java.io.*; Vu`O%[Q/  
import java.net.*; -'9sn/  
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public class FileSplitterFetch extends Thread { jPjFp35;zb  
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String sURL; //File URL A]FjV~PB  
long nStartPos; //File Snippet Start Position G2{.Ew  
long nEndPos; //File Snippet End Position =n}+p>\s  
int nThreadID; //Thread's ID w53+k\.  
boolean bDownOver = false; //Downing is over Cy~Pfty  
boolean bStop = false; //Stop identical P}El#y#&  
FileAccessI fileAccessI = null; //File Access interface :&/b}b!)AX  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException q i27:oJ  
{ )ww#dJn  
this.sURL = sURL; \Q5Jg  
this.nStartPos = nStart; }4; \sY  
this.nEndPos = nEnd; MMI7FlfY  
nThreadID = id; iA^GA8dn  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 `V;vvHP A  
} >c~Fgs  
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public void run() d`_X$P4y  
{ z8
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while(nStartPos < nEndPos && !bStop) jNIZ!/K  
{ lP!`lhc-^  
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try{ fFHT`"bD:  
URL url = new URL(sURL); 
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Rr#vv  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7%-+7O3ud  
String sProperty = "bytes="+nStartPos+"-"; 5F8sigr/h  
httpConnection.setRequestProperty("RANGE",sProperty); d@:4se-q+  
Utility.log(sProperty); hY?x14m$3  
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InputStream input = httpConnection.getInputStream(); &wlSOC')j  
//logResponseHead(httpConnection); @y (9LSs  
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byte[] b = new byte[1024]; \&&jzU2  
int nRead; 6NO_S  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) fR=B/`  
{ BCE}Er&  
nStartPos += fileAccessI.write(b,0,nRead); _VeZlk7k  
//if(nThreadID == 1) _$+lyea   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Yxa
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} `dH[&=S  
;xnJ+$//U  
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Utility.log("Thread " + nThreadID + " is over!"); PQmgv&!DP  
bDownOver = true; "]%.%
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//nPos = fileAccessI.write (b,0,nRead); PXZZPW/  
} `YDe<@6'  
catch(Exception e){e.printStackTrace ();} 3w=OvafT:  
} M>CW(X  
} L}bS"=B[&W  
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//打印回应的头信息 AXV+8$ :R  
public void logResponseHead(HttpURLConnection con) PKoB~wLH  
{ QMGMXa  
for(int i=1;;i++) %)7HBj(*J  
{ &ACM:&Ob  
String header=con.getHeaderFieldKey(i); dF$Fd{\4^  
if(header!=null) :nuMakZZ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ]j.??'+rg  
Utility.log(header+" : "+con.getHeaderField(header)); sLE@Cm]k  
else k_rtsN  
break; o}XbFLn  
} ':kj\$U  
} #tyHjk  
(UDR=7w)  
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public void splitterStop() Zh?1+Sz&  
{ [vuqH:Ln  
bStop = true; Mf0XQ3n`H  
} Sri,sZv  
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k T$yHB #  
} IfHB+H   
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/* f n9[Li  
**FileAccess.java :eQ?gM!,  
*//文件访问(定位，写) ;<Dou7=  
package NetFox; 4qtjP8Zv[  
import java.io.*; "]}+QK_  
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;m{*iKL6{  
public class FileAccessI implements Serializable{ %k8} IBL  
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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 3%Jg' Tr+  
RandomAccessFile oSavedFile; ^ q]BCOfJ(  
long nPos; ,5jE9  
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public FileAccessI() throws IOException OczVObbS  
{ .@
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this("",0); "R-1G/  
} m|<j9.iJ  
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public FileAccessI(String sName,long nPos) throws IOException * iW>i^  
{ KQ<pQkhv  
oSavedFile = new RandomAccessFile(sName,"rw"); <lh+mrXm  
this.nPos = nPos; RG=!,#X  
oSavedFile.seek(nPos); /g3U,?qP  
} "WOY`su>  
*9}2Bmojv  
:_YpSw<Q  
public synchronized int write(byte[] b,int nStart,int nLen) 1_uq46  
{ 'ypJGm  
int n = -1; is`Eqcj`dr  
try{ 0}]k>ndT  
oSavedFile.write(b,nStart,nLen); {.2A+JT,  
n = nLen; h
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} ckRWVw   
catch(IOException e) 0IoS|P}6a  
{ /X)fWO S6  
e.printStackTrace (); HXF5fs  
} IbAGnl{  
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return n; az3rK4g  
} Oa=0d;_
 
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} V}ZF\SG(K  
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/* D^P_3 B+  
**SiteInfoBean.java i[)H!%RV*  
*/ ZiodJ"r  
package NetFox; +~RiCZt  
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L}CjC>R!  
public class SiteInfoBean { :~BY[")  
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private String sSiteURL; //Site's URL ,dK<2XP  
private String sFilePath; //Saved File's Path bY7d  
private String sFileName; //Saved File's Name "Q;n-fqf  
private int nSplitter; //Count of Splited Downloading File YuXq  
W>036  
::N'tcZ^2  
public SiteInfoBean() SUxz &xH  
{//nSplitter的缺省值为5 /,A:HM>B  
//default value of nSplitter is 5 <<K GS  
this("","","",5); ~7T]l1]W%  
} Ub
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FS30RP3 `/  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) !Z2?dhS  
{ WjtmV2b<7  
sSiteURL= sURL; dX-Xzg  
sFilePath = sPath; 4vcUHa|4  
sFileName = sName; yhg^1l|t,  
this.nSplitter = nSpiltter; hSE\RX 9  
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} -kT *gIJ}  
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@#$5_uU8\(  
public String getSSiteURL() i/`N~r  
{ &wr0HrE\  
return sSiteURL; pq$`T|6^  
} > !k  
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public void setSSiteURL(String value) -bT1Qh X  
{ JSCe86a7<E  
sSiteURL = value;  Ew1> m'  
} |u{NM1,  
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public String getSFilePath() CEjMHP$=  
{ +c!v%uX  
return sFilePath; .XQ_,  
} ^%tmHDNL.  
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public void setSFilePath(String value) 8TIc;'b
RM  
{ v {E~R  
sFilePath = value; &|'k)6Rx  
} R@Ch3l@  
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public String getSFileName() M:i;;)cq  
{ $|-joY  
return sFileName; R:8\z0"L*  
} kX!TOlk3  
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public void setSFileName(String value) J+tpBPmb  
{ w4w[q
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sFileName = value; x%HX0= (  
} AdV&w: ^yf  
$2N)m:X0  
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public int getNSplitter() Q@zD'G>  
{ ;G!JKg  
return nSplitter; ,kiyxh^  
} . AJ(nJ)  
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public void setNSplitter(int nCount) [k qx%4q)  
{ \D Oqx  
nSplitter = nCount; 8{QN$Qkn  
} +zM
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} hfzmv~*  
>6xZF'4  
"SGq$3D  
/* -js:R+C528  
**Utility.java i> }P V  
*/ ?Ybgzb  
package NetFox; K1i@.`na/$  
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public class Utility { yb{ud  
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public Utility() KY}c}*0  
{ 3.[ fTrzJ  
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} \v|nRn,`-  
r57CyO  
//线程睡眠 {,V.IDs8[  
public static void sleep(int nSecond) UEkn@^&bg  
{ s#phs`v  
try{ B{x`^3qR  
Thread.sleep(nSecond); M1UabqQ  
} SxyXz8+e[  
catch(Exception e) s @AGU/v  
{ +hoZW R  
e.printStackTrace (); HP/f`8  
} :!',o]"4,k  
} _c[Bjip  
H]i.\2z  
//日志 c*fMWtPp  
public static void log(String sMsg) g7Xjo )  
{ a| w.G "W  
System.err.println(sMsg); $@WqM$  
} ;^fGQ]`4  
-
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HhZlHL  
public static void log(int sMsg) mI$<+S1!  
{ c~,OU7[  
System.err.println(sMsg); _f^JXd,7v  
} '+%<\.$  
} cD&QN9  
}M
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8
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/* {nr}C4]o  
**TestMethod.java  SK6?;_  
*/ ]x;*Z&  
package NetFox; QB3vp4pBg@  
pv3SAO4  
#Qir%\*V  
public class TestMethod { p'@|Oq&  
9n\b
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[m*E[0Hu  
public TestMethod() (vO\h8  
{ ///xx/weblogic60b2_win.exe lla?;^,  
try{ G@.TE7a2Z  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); f*(W%#*|  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); V?yTJJ21X  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 'MWu2L!F  
fileFetch.start();  _klT  
} w# iezo. 0  
catch(Exception e){e.printStackTrace ();} gG?sLgL:  
%I`%N2ss  
xE{PsN1 X;  
} r2h{#2  
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public static void main(String[] args) >GV(\In  
{ G(Ky7SZ  
new TestMethod(); KscugX*x  
} eH0^d5bH  
} ;z Qrree#  
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