http断点续传简单实现（java)

/*  f^b K=#  
**SiteFileFetch.java \TbVS8e^  
*/ J^ G  
package NetFox; Apfnx7Fv  
import java.io.*; ;Gd~YGW^#  
import java.net.*; [po "To  
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public class SiteFileFetch extends Thread { {x@|VuL=  
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SiteInfoBean siteInfoBean = null; //文件信息Bean |"Z{I3Umg  
long[] nStartPos; //开始位置 <+tD z(  
long[] nEndPos; //结束位置 q.V-LXM  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 $/Ov2z  
long nFileLength; //文件长度 VW<0Lt3  
boolean bFirst = true; //是否第一次取文件 (.23rVvnT@  
boolean bStop = false; //停止标志 j.|U=)E  
File tmpFile; //文件下载的临时信息 ,D=fFpn  
DataOutputStream output; //输出到文件的输出流 caq} &A]C  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） QG3&p<  
public SiteFileFetch(SiteInfoBean bean) throws IOException !mnUdR|>(  
{ D1T@R)j  
siteInfoBean = bean; #b)e4vwCq  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3yO=S0`  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 'i|rjW(  
if(tmpFile.exists ()) eV};9VJ$F  
{ {hdPhL  
bFirst = false; ~Xv=9@,h  
read_nPos(); `dW]4>`O  
} w0J|u'H  
else \".^K5Pm  
{ E>uVofhml
 
nStartPos = new long[bean.getNSplitter()]; 'Jj=RAV`  
nEndPos = new long[bean.getNSplitter()]; Q
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} >n*\bXf  
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} u8L$]vOg  
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public void run() V5mTu)tp5  
{ (6gK4__}]  
//获得文件长度 )"<8K}%!  
//分割文件 :d,^I@]  
//实例FileSplitterFetch ajH"Jy3A  
//启动FileSplitterFetch线程 Acm<-de  
//等待子线程返回 } cNW^4F  
try{ ~Y!kB:D5;~  
if(bFirst) MuI2?:~:*4  
{ .*/Fucr  
nFileLength = getFileSize(); nk=$B(h  
if(nFileLength == -1) 5.0e~zlM-  
{ elPE%'  
System.err.println("File Length is not known!"); S::>N.y  
} G}zZQy  
else if(nFileLength == -2) pdVQ*=c?M  
{ 3Ofc\  
System.err.println("File is not access!"); qUJ aeQ  
} &#
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else E-2eOT  
{ Y]g?2N=E  
for(int i=0;i<nStartPos.length;i++) G4-z3e,crr  
{ ,xi({{L*  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); I PCGt{B~  
} \XzM^K3  
for(int i=0;i<nEndPos.length-1;i++) _^ |2}
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{ [k%4eO2p"  
nEndPos = nStartPos[i+1]; 4=<*Vd`p  
} [.,>wo~  
nEndPos[nEndPos.length-1] = nFileLength; jLVl4h&  
} W;_E4  
} kUl  
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//启动子线程 42C<1@>zO  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !cX[-}Q  
for(int i=0;i<nStartPos.length;i++) YT
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{ R^&q-M=O[  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8Cx^0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 1Y
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nStartPos,nEndPos,i); gE7L L=x  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bn9;7`>.  
fileSplitterFetch.start(); t+Bf#:  
} 8?FueAM'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), GZ#aj|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]$iqa"{  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3lxc4@Zmd  
nEndPos = " + nFileLength); L"+
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// fileSplitterFetch[nPos.length-1].start(); 2f:^S/.A  
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//等待子线程结束 Q[4: xkU  
//int count = 0; fxQN+6;  
//是否结束while循环 $iw%
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boolean breakWhile = false; 6dqsFns}e  
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while(!bStop) G;iEo4\?  
{ y'C-[nk  
write_nPos(); Tny>D0Z#  
Utility.sleep(500); 
&:#h$`4  
breakWhile = true; =6nD sibf  
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for(int i=0;i<nStartPos.length;i++) L@Nu/(pB=  
{ LRb,VD:/Y  
if(!fileSplitterFetch.bDownOver) 4_?7&G0(  
{ 'fd1Pj9~$  
breakWhile = false; ib6^x:HGU  
break; AONDx3[   
} 2'0K WYM  
} uKr1Z2  
if(breakWhile) SI:ifR&T  
break; 2][DZl  
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 Ukz;0q  
//count++; V4w=/e_  
//if(count>4) Rd*[%)  
// siteStop(); oA-:zz>wL  
} #\rwLpC1u  
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System.err.println("文件下载结束！"); pJIv+  
} 3(E $I5  
catch(Exception e){e.printStackTrace ();} "f.Z}AbP  
} IZ,oM!Y  
|,C#:"z;  
}WLh8i?_  
//获得文件长度 Av J4\  
public long getFileSize() +~zXDBS9  
{ ~`MS~,,  
int nFileLength = -1; k"UO c=  
try{ l:B;zi`)oB  
URL url = new URL(siteInfoBean.getSSiteURL()); 1`0#HSO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #s-iy+/1oN  
httpConnection.setRequestProperty("User-Agent","NetFox"); Y-!YhWsS  
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int responseCode=httpConnection.getResponseCode(); L71!J0@a#  
if(responseCode>=400) nSx8E7 |V  
{ (t^n'V  
processErrorCode(responseCode); ~:4kU/]  
return -2; //-2 represent access is error -NGK@Yk22  
} ?i\;:<e4  
u
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String sHeader; fT\:V5-  
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} l667N  
for(int i=1;;i++) }=](p-]5  
{ 5f'DoT  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); /a9!Cf  
//Utility.log(in.readLine()); 1Nn@L2b 2  
sHeader=httpConnection.getHeaderFieldKey(i); Yf_6PGNzX  
if(sHeader!=null) ;r\(p|e  
{ Z4TL6]^R  
if(sHeader.equals("Content-Length")) w42OF7f  
{ zk_Eb?mhwV  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); :Sg&0Wj+#j  
break; .>g1$rj  
} ,$*IzL~  
} +\ _{x/u1  
else eP1nUy=T  
break; 5/><$06rq  
} ^?"\?M1  
} bp<^R  
catch(IOException e){e.printStackTrace ();} l(W[_ D  
catch(Exception e){e.printStackTrace ();} 4Aes#{R3v  
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Utility.log(nFileLength); gApoX0nrv  
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return nFileLength; jjs&`Fy,  
} G`h+l<  
~!iQ6N?PY  
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//保存下载信息（文件指针位置）  }alj[)  
private void write_nPos() <~emx'F|  
{ }3
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try{ [onqNp  
output = new DataOutputStream(new FileOutputStream(tmpFile)); BbOu/i|  
output.writeInt(nStartPos.length); or*HC&c7  
for(int i=0;i<nStartPos.length;i++) =v~1qWX  
{ AnsjmR:Jv  
// output.writeLong(nPos); _o6G6e,  
output.writeLong(fileSplitterFetch.nStartPos); &-l8n^  
output.writeLong(fileSplitterFetch.nEndPos); |
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} BG`s6aC|z<  
output.close(); 0>Z ;Ni  
} 
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catch(IOException e){e.printStackTrace ();} \{\MxXW  
catch(Exception e){e.printStackTrace ();} hn)a@  
} .9G<y 4  
4R%*Z~  
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//读取保存的下载信息（文件指针位置） 'm=*u SJK  
private void read_nPos() /TQ}} YVw  
{ <lxD}DH=  
try{ 4DWwbO  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); [dX`K`k  
int nCount = input.readInt(); z2c5m  
nStartPos = new long[nCount]; M(q'%XL^  
nEndPos = new long[nCount]; e&q?}Ho  
for(int i=0;i<nStartPos.length;i++)
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{ '(+<UpG_Q}  
nStartPos = input.readLong(); 8y';\(;  
nEndPos = input.readLong(); v`[Eb27W.  
} 's x\P[a  
input.close(); qOV[TP,  
} CG]Sj*SA~  
catch(IOException e){e.printStackTrace ();} :,pSWfK H  
catch(Exception e){e.printStackTrace ();} @ez Tbc3
 
} K ?$#ntp  
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private void processErrorCode(int nErrorCode) .0HZNWRtb  
{ ]uL+&(cr  
System.err.println("Error Code : " + nErrorCode); Y$8JM  
} t%1^Li  
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t=euE{c  
//停止文件下载 Kr`]_m  
public void siteStop() +V862R4,o  
{ D<{{ :7n  
bStop = true; !G5a*8]  
for(int i=0;i<nStartPos.length;i++) &F$:Q:* *  
fileSplitterFetch.splitterStop(); d5I f"8`@  
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} 8[%Ao/m  
} %bXtKhg5eJ  
//负责部分文件的抓取 Mn:/1eY  
**FileSplitterFetch.java 7cg*|E@  
*/ -ZOBAG*  
package NetFox; d^ ZMS~\*  

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import java.io.*; ra '  
import java.net.*; o`,Qku k  
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public class FileSplitterFetch extends Thread { Rs& @4_D  
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String sURL; //File URL 4pz|1Hw7  
long nStartPos; //File Snippet Start Position 8 (jUe  
long nEndPos; //File Snippet End Position ~=r^3nZR/J  
int nThreadID; //Thread's ID )wXuwdc[  
boolean bDownOver = false; //Downing is over R! s6% :Yg  
boolean bStop = false; //Stop identical
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FileAccessI fileAccessI = null; //File Access interface s$h] G[x  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException L}{`h  
{ ^ ?hA@{T/1  
this.sURL = sURL; "R #k~R  
this.nStartPos = nStart; =8G&3 R  
this.nEndPos = nEnd; o@>? *=  
nThreadID = id; qd@&59zSh  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :bU(S<%M  
} bJr[I  
#:fQ.WWO  
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public void run() zRl~^~sY  
{ /Wk9-uH  
while(nStartPos < nEndPos && !bStop) ri~<~oB2:  
{ =(AtfW^H  
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try{ 3cl9wWlJ_E  
URL url = new URL(sURL); V% TH7@y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '$|UwT`s  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5R MS(  
String sProperty = "bytes="+nStartPos+"-"; d4[(8} x$/  
httpConnection.setRequestProperty("RANGE",sProperty); u8
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Utility.log(sProperty); ^u)z{.z'H/  
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InputStream input = httpConnection.getInputStream(); RH)EB<PV  
//logResponseHead(httpConnection); wy1X\PJjH  
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byte[] b = new byte[1024]; _=6 rE  
int nRead; +WJ(QZEhD  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) HYr}wG  
{ 5,"l0nrk  
nStartPos += fileAccessI.write(b,0,nRead); kW3E =pr  
//if(nThreadID == 1) igf)Hb;5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !%mAh81{&/  
} $Byj}^;1  
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Utility.log("Thread " + nThreadID + " is over!"); Cz#Z<:  
bDownOver = true; T4e\0.If  
//nPos = fileAccessI.write (b,0,nRead); JF9y
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} \b8sG"G  
catch(Exception e){e.printStackTrace ();} !#ri5{od  
} =Yo1v=wxN  
} eS/B24;*  
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//打印回应的头信息 ".*x!l0y7  
public void logResponseHead(HttpURLConnection con) co4h*?q  
{ ;E2>Ovv  
for(int i=1;;i++) [a[/_Sf{  
{ D:\g,\Z  
String header=con.getHeaderFieldKey(i); /h2b;"  
if(header!=null) bte~c  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); {'+QH)w(  
Utility.log(header+" : "+con.getHeaderField(header)); z"4]5&3A  
else =`n]/L"Q  
break; cNpe_LvW  
} 4o:hyh   
} R$k
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2],_^XBvB  
public void splitterStop() p4>$z& _  
{ #h!*dj"  
bStop = true; \/7i-B]G7  
} 3CjL\pIC  
v ]Sl<%ry  
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} :m=m}3/:  
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/* D-imL;|  
**FileAccess.java j Ib  
*//文件访问(定位，写) gQSNU_o Z  
package NetFox; Ax3W2s  
import java.io.*; ,''cNV  
8?t"C_>*e  
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public class FileAccessI implements Serializable{ I:(m aMc  
ln*icaDqf  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 B (/U3}w-  
RandomAccessFile oSavedFile; 39U5jj7i  
long nPos; k@>\LR/v  
:Br5a34q  
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public FileAccessI() throws IOException gMWBu~;!  
{ 1PaUI#X"2F  
this("",0); 31^cz*V  
} wyx(FinIH  
O40+M)e]  
n6WY&1ZE~  
public FileAccessI(String sName,long nPos) throws IOException c;f!!3&  
{ \u-0v.+|  
oSavedFile = new RandomAccessFile(sName,"rw"); }g+;y  
this.nPos = nPos; -${DW^txMZ  
oSavedFile.seek(nPos); p]D]: Z}P  
} DVZdClAL  
-kz4
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public synchronized int write(byte[] b,int nStart,int nLen) E! /[gZ  
{ ;^ wd_  
int n = -1; H?1xjY9sl  
try{ \e=_ 2^v!_  
oSavedFile.write(b,nStart,nLen); zo{/'BnU  
n = nLen; A*h{Lsx;  
} )O+}T5c=  
catch(IOException e) iq#b#PYA  
{ %A1@&xrbl  
e.printStackTrace (); -Ue$T{;RoH  
} +'@+x'/{^  
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y
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return n; :nHKl  
} }K1 0Po'  
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} `J<*9dq%  
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/* 4EI7W,y  
**SiteInfoBean.java 'crlA~&#/  
*/ 5wB =>  
package NetFox; +cJy._pi!  
5*PYT=p}  
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public class SiteInfoBean { .Ig+Dj{)  
+h^jC9,m~{  
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private String sSiteURL; //Site's URL 8,D 2^Gg  
private String sFilePath; //Saved File's Path (@X~VACT  
private String sFileName; //Saved File's Name ~"pKe~h   
private int nSplitter; //Count of Splited Downloading File kh~'Cn "O  
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public SiteInfoBean() 7A\Cbu2tf  
{//nSplitter的缺省值为5 7g=2Z[o  
//default value of nSplitter is 5 k$5 s{q  
this("","","",5); Vt^3iX{!  
} 2 &/v]  
{^CT}\=>  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) nMDxH$O  
{ rWys'uc  
sSiteURL= sURL; &uP~rEJl+  
sFilePath = sPath; o)6pA^+  
sFileName = sName; h1 WT
  
this.nSplitter = nSpiltter; sAo& uZ  
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MUOa@O,  
} bQe^Px5 !.  
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public String getSSiteURL() ~/NKw:  
{ ZZQG?("S'  
return sSiteURL; YDC mI@  
} hLJM%on  
_AV1WS;^^8  
4?N8R$  
public void setSSiteURL(String value) }'r[m5T  
{ ]v[|B  
sSiteURL = value; b[z]CP  
} jVLA CWH  
2._X|~0a  
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public String getSFilePath() !8 &=y  
{ T5urZq*R  
return sFilePath; +% /s*EC'w  
} 0CSv10Tg  
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'65LKD  
public void setSFilePath(String value) ~HQ9i%exg  
{ Li*eGlId  
sFilePath = value; bo.(zAz  
} HM>lg`S  
 u66XN^  
Z*G(5SqUh"  
public String getSFileName() W\1i,ew>  
{ f%5zBYCgC  
return sFileName; XC{eX&,2x  
} \~P=U;l=pO  
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MO;X>D=  
public void setSFileName(String value) e1//4H::t  
{ A+@&"  
sFileName = value; rt JtK6t  
} H>r!i4l  
3_JCU05H}  
TW !&p"Us+  
public int getNSplitter() (&$VxuJ+6y  
{ t1E[uu,V8  
return nSplitter; 6c0>gUQx-  
} /0\ mx4u  
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#plY\0E@  
public void setNSplitter(int nCount) ~>9_(L  
{ q2HYiH^L  
nSplitter = nCount; 4k./(f2+  
} RN=` -*E1  
} R^{)D3  
=4d (b ;  
Z{?G.L*/  
/* q7u'_R,;  
**Utility.java UMX@7a,[3  
*/ (a9d
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package NetFox; \.M*lqI  
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@cU&n6C@  
public class Utility { 8enEA^  
:[;hu}!&  
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public Utility() \h8
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{ `y+tf?QN  
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} e<r,&U$  
F;^F+H  
//线程睡眠 e%W$*f  
public static void sleep(int nSecond) yCCrK@{oo  
{ r(gXoq_w  
try{ !?Wp+e6  
Thread.sleep(nSecond); I%urz!CNE*  
} B=|cS;bM$3  
catch(Exception e) X$/2[o#g  
{ dH
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e.printStackTrace (); NHlk|Y#6b  
} uslQ*7S[^  
} +}jJ&Z9)  
86nN"!{l:  
//日志 arf8xqR-U]  
public static void log(String sMsg) +^;JS3p@\  
{ <$JaWL  
System.err.println(sMsg); s(W|f|R  
} +{
/  
g}]t[}s1]  
# W"=ry3{  
public static void log(int sMsg) ?6'rBH/w  
{ rj!0GI  
System.err.println(sMsg); #c2ymQm  
} utr:J  
} Y))NK'B5  
^j7azn  
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/* ,0LU~AGe   
**TestMethod.java  T Q,?>6n  
*/ 4*$G & TX  
package NetFox; e1P"[|9>R  
7g3>jh  
}f2r!7:x  
public class TestMethod { U(x]O/m  
m8.U &0  
23gPbtq/  
public TestMethod() .9.2Be  
{ ///xx/weblogic60b2_win.exe y|wc,n%L>  
try{ ?,/U^rf^4  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~g.$|^,.O/  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); kBN+4Dr/$  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }V\N16f  
fileFetch.start(); m^qBxA  
} H= X|h)  
catch(Exception e){e.printStackTrace ();} 5 (A5Y-B  
cph:y  
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} ^Ox3XC  
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public static void main(String[] args) $
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{ q:g2Zc'Y~W  
new TestMethod(); f7}*X|_Y  
} Dl}$pN  
}
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