http断点续传简单实现（java)

/* -ucR@P]  
**SiteFileFetch.java Gt!Hm(  
*/ )coA30YR  
package NetFox; Th~pju  
import java.io.*; (ueH@A"9;  
import java.net.*; }JT&lyO< b  
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public class SiteFileFetch extends Thread { X&K,,C  
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SiteInfoBean siteInfoBean = null; //文件信息Bean K:pG<oV|}  
long[] nStartPos; //开始位置 1'B=JyR~K  
long[] nEndPos; //结束位置 xelh!AtE  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7FP"]\x  
long nFileLength; //文件长度 ~$Z_#,|i?  
boolean bFirst = true; //是否第一次取文件 o i~,}E_  
boolean bStop = false; //停止标志 _tO2PIL@Z  
File tmpFile; //文件下载的临时信息 r&L1jT.  
DataOutputStream output; //输出到文件的输出流 Vr&v:8:wb  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） tfe'].uT  
public SiteFileFetch(SiteInfoBean bean) throws IOException Z@Qf0 c  
{ 2"Y=*s  
siteInfoBean = bean; 1fF\k#BE-%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;{n*F=%uC  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); G0ENk|wbbj  
if(tmpFile.exists ()) !A_KCM:Ym  
{ VrFI5_M/  
bFirst = false; mj y+_  
read_nPos(); o%Qn%gaX  
} wo^1%:@/2  
else F#efs6{  
{ !}xRwkN  
nStartPos = new long[bean.getNSplitter()]; D[Ld=e8t  
nEndPos = new long[bean.getNSplitter()]; Ax!fvcsN  
} O}7aX '  
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} MpJx>
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public void run() IRI<no  
{ uYc&Q$U  
//获得文件长度 Zo,]Dx  
//分割文件 a+\s0Qo<  
//实例FileSplitterFetch HMR!XF&JjC  
//启动FileSplitterFetch线程 8ZO~=e  
//等待子线程返回 Gv\fF;,R  
try{ nON
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if(bFirst) v/wR)9  
{ 061f  
nFileLength = getFileSize(); I,lzyxRP  
if(nFileLength == -1) An !i  
{ NW Pd~l+  
System.err.println("File Length is not known!"); .GPuKP|  
} h3A|nd>\  
else if(nFileLength == -2) j;*= ^s  
{ aK9zw  
System.err.println("File is not access!"); MK4CggoC  
} ;WL0  
else 5d82Ms  
{ f<3r;F7  
for(int i=0;i<nStartPos.length;i++) 0 f"M-x  
{ >[g'i+{  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 7jF2m'(  
} t]pJt  
for(int i=0;i<nEndPos.length-1;i++) &44?k:  
{ ]^l-k@  
nEndPos = nStartPos[i+1]; Xc]Q_70O  
} Qp>Q-+e0  
nEndPos[nEndPos.length-1] = nFileLength; H0mDs7  
} O,KlZf_B  
} =TXc- J  
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//启动子线程 UIw6~a3E  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];  eYRm:KC  
for(int i=0;i<nStartPos.length;i++) YA^g[,  
{ ,[Z;"wE  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `#N7ym;s@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), a^&3?3   
nStartPos,nEndPos,i); ia/_61%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {{_,YO^w  
fileSplitterFetch.start(); 4:v{\R  
} ' 9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), & |o V\L  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); -3:x(^|:K  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", YcBAW4B`  
nEndPos = " + nFileLength); fBt7#Tc=U  
// fileSplitterFetch[nPos.length-1].start(); j-etEWOTr  
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&rxR"^x\  
//等待子线程结束 aMjCqu05  
//int count = 0; jl4rEzVu  
//是否结束while循环 bjq2XP?LL  
boolean breakWhile = false; Mxe  
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while(!bStop) Q /\Hc  
{ K?+Rq  
write_nPos(); `{I-E5x  
Utility.sleep(500); .c.#V:XZ#U  
breakWhile = true; v|mZcAz  
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for(int i=0;i<nStartPos.length;i++) tI(co5 W  
{ lL:J:  
if(!fileSplitterFetch.bDownOver) c^8y/wfok  
{ n-_-
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breakWhile = false; ^KMZB  
break; U9B|u`72  
} _/!IjB:(70  
} c8jq.y v  
if(breakWhile) u5FlT3hY.  
break; = 8%+$vX  
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//count++; RA+k/2]y!  
//if(count>4) "$BWP  
// siteStop(); z<mU$<  
} [(N<E/m%B  
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System.err.println("文件下载结束！"); Wz7jB6AWA  
} "L" 6jT  
catch(Exception e){e.printStackTrace ();} W7"ks(  
} oFV>b  
)/9/p17:xu  
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//获得文件长度 ~(`iRxK  
public long getFileSize() kSw.Q2ao  
{ ~dK)U*Q  
int nFileLength = -1; IPnbR)[%  
try{ wy$9QN  
URL url = new URL(siteInfoBean.getSSiteURL()); lH^[b[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); R@r"a&{/  
httpConnection.setRequestProperty("User-Agent","NetFox"); r#pC0Yj!3  
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int responseCode=httpConnection.getResponseCode(); 7=8e|$K_  
if(responseCode>=400) ZWSYh>"  
{ I%whM~M1+  
processErrorCode(responseCode); 3s
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return -2; //-2 represent access is error LdA
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} "tbKKh66  
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String sHeader; !285=cxz  
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for(int i=1;;i++) v>71?te  
{ rr#&0`]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Khxl'qj  
//Utility.log(in.readLine()); ALiXT8q  
sHeader=httpConnection.getHeaderFieldKey(i); \5Jpr'mY5  
if(sHeader!=null) DxT8;`I%  
{ gX34
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if(sHeader.equals("Content-Length")) n-{G19?  
{ 7!`,P  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); snV,rZ  
break; s7<x~v+^  
} FHI`/  
} RI"A'/56  
else -lm\~VZT3  
break; 0p_/eWww-  
} g~Zel}h#  
} ,\f!e#d  
catch(IOException e){e.printStackTrace ();} `Q*L!/K+  
catch(Exception e){e.printStackTrace ();} nmVL%66K  
{ CkxUec  
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Utility.log(nFileLength); V3-5:z  
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return nFileLength; R$=UJ}>  
} w Maib3Q  
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//保存下载信息（文件指针位置） |jniI(  
private void write_nPos() Uax- z  
{ }Z-]m  
try{ qd
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output = new DataOutputStream(new FileOutputStream(tmpFile)); ]z,W1Zs?  
output.writeInt(nStartPos.length); &<-Sxjj  
for(int i=0;i<nStartPos.length;i++) <5A(rDij  
{ B8:_yAv o  
// output.writeLong(nPos); &'UYV>  
output.writeLong(fileSplitterFetch.nStartPos); aO?(ZL  
output.writeLong(fileSplitterFetch.nEndPos); e/EfWwqt  
}  tQB+_q z  
output.close(); %^g BDlR^  
} Y0=qn'`.  
catch(IOException e){e.printStackTrace ();} /z*?:*  
catch(Exception e){e.printStackTrace ();} ,K8O<Mw8  
} GH![rK  
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//读取保存的下载信息（文件指针位置） ` a5$VV%J  
private void read_nPos() !L+*.k:  
{ |Z<NM#1  
try{ `(?E-~#'  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); qIa|sV\w0  
int nCount = input.readInt(); H~1*`m  
nStartPos = new long[nCount]; -#H>kbs  
nEndPos = new long[nCount]; ^S'}RZ*>  
for(int i=0;i<nStartPos.length;i++) ;GO>#yg4Eh  
{ s2Ivd*=mT  
nStartPos = input.readLong(); veg\A+:'  
nEndPos = input.readLong(); !q! =VC  
} ~fn2B  
input.close(); %8tlJQ
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} vAi kd#C)  
catch(IOException e){e.printStackTrace ();} T@uY6))>F  
catch(Exception e){e.printStackTrace ();} Nrva?W_i  
} Iw8;",e2  
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private void processErrorCode(int nErrorCode) %lAJ]$m  
{ Zg%U4m:  
System.err.println("Error Code : " + nErrorCode); l~wx8 ,?G  
} P}y}IR{6  
^_r8R__S:  
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//停止文件下载 _) 2fXG!  
public void siteStop() l=[<gPE  
{ 8l0%:6XbI  
bStop = true; Ps(3X@  
for(int i=0;i<nStartPos.length;i++) CE:TQzg  
fileSplitterFetch.splitterStop(); B5aFt ;Vj  
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} $ckX H,l_  
} 9 W><m[O  
//负责部分文件的抓取 7\'vSHIL  
**FileSplitterFetch.java @;M( oFS9  
*/ 3Ln~"HwP  
package NetFox; V= U=  
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import java.io.*; Glcl7f"<^  
import java.net.*; &xM
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public class FileSplitterFetch extends Thread { h #Od tc1)  
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String sURL; //File URL ngj=w;7~+  
long nStartPos; //File Snippet Start Position I4ZL+a  
long nEndPos; //File Snippet End Position N\1!)b  
int nThreadID; //Thread's ID &/}]9 #  
boolean bDownOver = false; //Downing is over | Uf6k`  
boolean bStop = false; //Stop identical sptDzVM  
FileAccessI fileAccessI = null; //File Access interface _9wX8fh3D  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException }:7'C. ."  
{ >_(Xb%w  
this.sURL = sURL; "]Wrir?l  
this.nStartPos = nStart; rY_)N^B|nF  
this.nEndPos = nEnd; O E0w/{  
nThreadID = id; r4k=i
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 uOc:^  
} )uiYu3 I  
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public void run() VG^*?62  
{ r5> FU>7'  
while(nStartPos < nEndPos && !bStop) oE[wOq+  
{ p<*3mbgGO  
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try{ xGCW-YR9  
URL url = new URL(sURL); !*ct3{m  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 
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httpConnection.setRequestProperty("User-Agent","NetFox"); M.))UKSF  
String sProperty = "bytes="+nStartPos+"-"; $As;Tvw.  
httpConnection.setRequestProperty("RANGE",sProperty); @|v4B[/  
Utility.log(sProperty); u~7m
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InputStream input = httpConnection.getInputStream(); xQ9P'ru  
//logResponseHead(httpConnection); X:bv ?o>Y  
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byte[] b = new byte[1024]; 2%i_SX[  
int nRead; G=/a>{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Qyvn A|&  
{ C']TO/2q
 
nStartPos += fileAccessI.write(b,0,nRead); q,3_)ZOq  
//if(nThreadID == 1) |9T3" _MmJ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); '=K [3%U  
} bhDV U(%I6  
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Utility.log("Thread " + nThreadID + " is over!"); qPGpN0M`  
bDownOver = true; P&"8R  
//nPos = fileAccessI.write (b,0,nRead); $$ouqLu  
} Xptb4]  
catch(Exception e){e.printStackTrace ();} 6MQ+![fN  
} gR}>q4b  
} l{ja2brX  
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//打印回应的头信息 <0T5W#H`D  
public void logResponseHead(HttpURLConnection con) 4$.$j=Ct."  
{ GTL gj'B  
for(int i=1;;i++) "<uaG?:  
{ g"aWt% P  
String header=con.getHeaderFieldKey(i); ^F2OTz4n  
if(header!=null) jA_wOR7$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); L[o;@+32  
Utility.log(header+" : "+con.getHeaderField(header)); m}&cX
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else w
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break; e^2e[rp0  
} ya7PF~:E-  
} F5la:0fb  
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public void splitterStop() IlQNo 1  
{ ATx6YP@7~  
bStop = true; U$jw8I'.  
} D#Qfa
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} eD5:0;X2  
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/* W[Kv Qt3%  
**FileAccess.java )c|S)iJ7=z  
*//文件访问(定位，写) !-%fCg(B  
package NetFox; I3sH8/*  
import java.io.*; gwVfiXR4  
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public class FileAccessI implements Serializable{ {6H%4n  
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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 |m{Q_zAB  
RandomAccessFile oSavedFile; 8 Z|c!QIU  
long nPos; qYpuo D  
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public FileAccessI() throws IOException b^
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{ }xhat,9  
this("",0); 5'iJN$7  
} mBWE^  
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public FileAccessI(String sName,long nPos) throws IOException T.ZPpxY  
{ "
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oSavedFile = new RandomAccessFile(sName,"rw"); BCnf'0q  
this.nPos = nPos; T'YHV}b}vX  
oSavedFile.seek(nPos); kg@D?VqJP  
} x1H?e8  
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public synchronized int write(byte[] b,int nStart,int nLen) BC!n;IAe  
{ MV8Lk/zd?A  
int n = -1; WH:[Y7D  
try{ cfZG3"  
oSavedFile.write(b,nStart,nLen); KKMzhvf]#  
n = nLen; epz'GN]V  
} 85;hs  
catch(IOException e) J6m`XC  
{ -anLp8G*  
e.printStackTrace (); BPf;!.  
} Y)D~@|D,  
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return n; DGfhS`
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} ?Q$LIoR  
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} >y P`8Oq[  
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/* PqOy"HO  
**SiteInfoBean.java ,$;g'z!N  
*/ m]g"]U:  
package NetFox; oECM1'=Bf  
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public class SiteInfoBean { <9za!.(zu  
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private String sSiteURL; //Site's URL w8~J5XS  
private String sFilePath; //Saved File's Path g4n&k  
private String sFileName; //Saved File's Name F[aow$",+}  
private int nSplitter; //Count of Splited Downloading File
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public SiteInfoBean() {?a9>g-BW  
{//nSplitter的缺省值为5 G5^gwG+  
//default value of nSplitter is 5 WZ.d"EE"  
this("","","",5); 3F%Qq7v  
} j s(E-d/  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) , N:'Z  
{ ,gU%%>-_~w  
sSiteURL= sURL; | ?6
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sFilePath = sPath; Q:iW k6  
sFileName = sName; 4SG22$7W  
this.nSplitter = nSpiltter; C:tA|<b|  
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} Ru%: z>Y  
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public String getSSiteURL() vFfvvRda4x  
{ Z=: oIAe  
return sSiteURL; d6lhA
7  
} !g? ~<`  
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public void setSSiteURL(String value) //--r5Q  
{ {$iJYS\  
sSiteURL = value; (xU+Y1*g"%  
} k&nhF
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_ Ko
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public String getSFilePath() _/[n/"gn  
{ 'e6W$?z  
return sFilePath; C9-9cdW H  
} MDkIaz\U  
}9C5U>?  
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public void setSFilePath(String value) 9X&Xs/B  
{ >/"XX,3  
sFilePath = value; H*QN/{|RU  
} ~qNpPIrGr  
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=#XsY,r  
public String getSFileName() A!v-[AI[  
{ CiP-Zh[gZ  
return sFileName; SwQ.tK1p  
} zIbl[[M&  
/,v:!*  
#
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public void setSFileName(String value) X7kJ
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{ ;>=hQC{f>  
sFileName = value; |Sg *j-.  
} K*J8(/WkD  
a@@!Eg A  
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public int getNSplitter() 8G
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{ RCt)qh+  
return nSplitter; @"9y\1u  
} e,E;\x &  
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public void setNSplitter(int nCount) /3%]Ggwe  
{ /2u;w!oi.  
nSplitter = nCount; ilK8V4k<T)  
} |PN-,f{-  
} |xzqYu?o  
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/* ~4}m'#!  
**Utility.java [[D}
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*/ P's<M  
package NetFox; )ymF:]QC  
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public class Utility { Oe9
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public Utility() KHr8\qLH  
{ 1jmhh!,  
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| 7>1)  
} RA[` Cp"  
r"fu{4aX  
//线程睡眠 va8:QHdU  
public static void sleep(int nSecond) uMsKF%m  
{ 7k6rhf7H  
try{ mQ%kGqs  
Thread.sleep(nSecond); 9+QLcb  
} NtTLvO6  
catch(Exception e) o\]e}+1[o  
{ J=K3S9:n]g  
e.printStackTrace (); z,rWj][P  
} ~73"AWlp  
} #`"'  
*ep!gT*4  
//日志 4BEVG&Ks  
public static void log(String sMsg) >K\ 79<x|  
{ cDs#5,  
System.err.println(sMsg); SATZ!  
} 8gC(N3/E"  
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public static void log(int sMsg) 2L<TqC{,-  
{ ]VJcV.7`  
System.err.println(sMsg); 4d]  
} 6%S>~L66  
} ;8 M
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/* wuYo@DDU#  
**TestMethod.java q/OraPAB  
*/ cJ8*[H<NV  
package NetFox; xC;$/u%'  
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tW=0AtZl]  
public class TestMethod { Kg](kP  
95]%j\  
R&xD|w8UjM  
public TestMethod() Jy|Mfl%d  
{ ///xx/weblogic60b2_win.exe .j&jf^a5  
try{ 2:DpnLU5  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); C)C;U&Qd  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Kv#daAU  
SiteFileFetch fileFetch = new SiteFileFetch(bean); aRG[F*BY  
fileFetch.start(); *znCe(dd  
} %Vt@7SwRJ  
catch(Exception e){e.printStackTrace ();} t1Jz?Ix6%  
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|9\Lv$
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} D[tGbk  
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public static void main(String[] args) 4|+ |L_  
{ qw, >~  
new TestMethod(); _^'k_a  
} ;%k%
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} t#pY2!/T3  
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