http断点续传简单实现（java)

/* nGqD{!i<  
**SiteFileFetch.java i:coNK)4  
*/ qP}187Q
1  
package NetFox; +%%Ef]  
import java.io.*; %gb4(~E+N  
import java.net.*; 1K`7  
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public class SiteFileFetch extends Thread { ..5rW0lr  
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SiteInfoBean siteInfoBean = null; //文件信息Bean c :{#
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long[] nStartPos; //开始位置 _3'FX#xc  
long[] nEndPos; //结束位置 =>kE`"{!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >Yf)]e-  
long nFileLength; //文件长度 G'M;]R9EP  
boolean bFirst = true; //是否第一次取文件 (5Z*m<]c  
boolean bStop = false; //停止标志 ~7$4w# of0  
File tmpFile; //文件下载的临时信息 ~Gz b^  
DataOutputStream output; //输出到文件的输出流 Uf ?._&:  
&I|\AG"X}  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） J:!m49fF  
public SiteFileFetch(SiteInfoBean bean) throws IOException Hv~&RZpe  
{  KDX1_r=Y  
siteInfoBean = bean; q|}%6ztv-  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); fUg<+|v*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `v|w&ty*  
if(tmpFile.exists ()) 1ab_^P  
{ 0S%xm'|N  
bFirst = false; z3bRV{{YqN  
read_nPos(); iW #|N^
 
} !d)Vr5x  
else rEF0A&5  
{ a^ __Z3g,  
nStartPos = new long[bean.getNSplitter()]; '=Z]mi/aw  
nEndPos = new long[bean.getNSplitter()]; C2[* $ 1U  
} .EF(<JC?  
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} 6Kbc:wlR  
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public void run() ^]cl:m=*  
{ '<JNS8h  
//获得文件长度 D["~G v  
//分割文件 ye-EJDZN  
//实例FileSplitterFetch U $2"ZyFii  
//启动FileSplitterFetch线程 
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//等待子线程返回 'BiR ,M$mY  
try{ 4
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if(bFirst) r
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{ <Pm!#)-g9  
nFileLength = getFileSize(); Ki,SFww8r  
if(nFileLength == -1) zJ=lNb?q  
{ wOLDHg_  
System.err.println("File Length is not known!"); VbG#)>"F  
} S <Rb
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else if(nFileLength == -2) ]VCVV!G_=n  
{ 9Ev<t\B  
System.err.println("File is not access!"); 5Qh$>R4!"  
} Z"pCDW)  
else [B,w\PLub  
{ l+vD`aJ3  
for(int i=0;i<nStartPos.length;i++) vh/&KTe?:  
{ ^c-8~r|y,  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); <l.l6okp  
} Pss$[ %  
for(int i=0;i<nEndPos.length-1;i++) V`WSZ  
{ y v58~w*"  
nEndPos = nStartPos[i+1]; F{*h~7D-|  
} s;ivoGe}  
nEndPos[nEndPos.length-1] = nFileLength; 6L!/#d0  
} sy]hMGH:3W  
} x_+-TC4IXn  
1o8C4?T&  
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//启动子线程 !S3^{l-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; "M!]t,?S  
for(int i=0;i<nStartPos.length;i++)  =] +owl2  
{ N8E  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), E^`-:L(_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ]wZlJK`K  
nStartPos,nEndPos,i); {M^BY,%*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [KMNMg  
fileSplitterFetch.start(); */6lyODf  
} TFAd  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +e87/\5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $VxKv7:  
nEndPos = " + nFileLength); nf0]<x2  
// fileSplitterFetch[nPos.length-1].start(); \V_Tc`  
VrIR!9%:  
r6QshCA"  
//等待子线程结束 N;q)r  
//int count = 0; ) w1`<7L  
//是否结束while循环 Iysp)  
boolean breakWhile = false; lS96Z3k"SB  
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while(!bStop) II'"Nkxd  
{ SYd6D@^2j  
write_nPos(); xjy(f~'  
Utility.sleep(500); xep8CimP'  
breakWhile = true; W;T5[
 
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for(int i=0;i<nStartPos.length;i++) &~aS24c  
{ kRb %:*  
if(!fileSplitterFetch.bDownOver) *6bO2LO"  
{ /os,s[w  
breakWhile = false; L"tzUYxg  
break; 'N3)>!Y:8  
} b]b+PK*h  
} ~JS B
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if(breakWhile) `tPVNO,l  
break; 6Qk[TL)t  
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//count++; RuGG3"|  
//if(count>4) 3c=>;g  
// siteStop(); 6]sP"  
} WS ^,@>A  
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System.err.println("文件下载结束！"); .%EYof  
} NZ"nG<;5  
catch(Exception e){e.printStackTrace ();} r])V6 ^U  
} +'$5Jtz  
SU5O+;{`'  
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//获得文件长度 ka_(8  
public long getFileSize() +# 3e<+!F  
{ '.wb= C  
int nFileLength = -1; q-s(2C  
try{ `=$p!H8  
URL url = new URL(siteInfoBean.getSSiteURL()); i IM\_<?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I.[Lv7U-  
httpConnection.setRequestProperty("User-Agent","NetFox"); }/lyrj
V  
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int responseCode=httpConnection.getResponseCode(); P~M[i9 V  
if(responseCode>=400) +#Wwah$  
{ v5\5:b{/  
processErrorCode(responseCode); V}Ee1C  
return -2; //-2 represent access is error 6f:uAFwG  
} );zLgNx,  
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String sHeader; <aLS4  
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for(int i=1;;i++) GC~nr-O  
{ >xXC=z+g]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); KM+[1Ze$  
//Utility.log(in.readLine()); %
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sHeader=httpConnection.getHeaderFieldKey(i); |\W53,n9  
if(sHeader!=null) r
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{ /9=r.Vxh  
if(sHeader.equals("Content-Length")) oY+p;&H  
{ guG&3{&\s  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); TuEM  
break; =I aWf  
} c5_/i7  
} iu?gZVyka  
else Bi2 c5[3  
break; shR|  
} K3Bw3j 9  
} e#)NYcr6  
catch(IOException e){e.printStackTrace ();}  wX5q=I  
catch(Exception e){e.printStackTrace ();} d N$,AOT  
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Utility.log(nFileLength);
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return nFileLength; Ze[,0Y!u&  
} p|(SR~;6  
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//保存下载信息（文件指针位置） !,dp/5 V  
private void write_nPos() XF+4*),  
{ O}w%$ mq  
try{ I tb_ H  
output = new DataOutputStream(new FileOutputStream(tmpFile)); YS#*#!ZMn?  
output.writeInt(nStartPos.length); )Gm9x]SVl  
for(int i=0;i<nStartPos.length;i++) j XH9Pq4  
{ 3FtL<7B'.  
// output.writeLong(nPos); 
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output.writeLong(fileSplitterFetch.nStartPos); 9;'#,b*(  
output.writeLong(fileSplitterFetch.nEndPos); IJ~j(.W  
} |RXQ_|  
output.close(); l2kGFgc  
} DJ DQH\&  
catch(IOException e){e.printStackTrace ();} #N"u 0  
catch(Exception e){e.printStackTrace ();} |j-ng;  
} $_iE^zZaU^  
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//读取保存的下载信息（文件指针位置）  DR{O.TX  
private void read_nPos() x.#E3xI  
{ m^0vux  
try{ F(#?-MCs  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); NYr)=&)Ke.  
int nCount = input.readInt(); *FktI\tS  
nStartPos = new long[nCount]; EK5$z>k>m  
nEndPos = new long[nCount]; yQ$]`hr;  
for(int i=0;i<nStartPos.length;i++) uorX;yekC  
{ %S"85#R5E  
nStartPos = input.readLong(); tRpY+s~Fq  
nEndPos = input.readLong(); araXE~Ac  
} 7f}uRXBV$A  
input.close(); 14"57Jt8  
} J jm={+@+  
catch(IOException e){e.printStackTrace ();} 3LT~-SvL
 
catch(Exception e){e.printStackTrace ();} w|6/i/X  
} <gFa@at  
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private void processErrorCode(int nErrorCode) swxX3GR  
{ 2QRO$NieV  
System.err.println("Error Code : " + nErrorCode); 8}m J)9<7  
} p<{P#?4 g  
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//停止文件下载 SAdE9L =d  
public void siteStop() N<8\.z5:<  
{ ,f2oO?L}  
bStop = true; D*ZjoU  
for(int i=0;i<nStartPos.length;i++) Ku%tM7ad  
fileSplitterFetch.splitterStop(); yKoZj   
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rHTZM,zM=H  
} 4`,7tj  
} `hZh}K^  
//负责部分文件的抓取 9xO@_pkX  
**FileSplitterFetch.java K^U=
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*/ H7GI`3o  
package NetFox; ZX` \so,&,  
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import java.io.*; fj;ZGbg-O  
import java.net.*; )\#*~73  
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public class FileSplitterFetch extends Thread { V:GypY)  
A4!X{qUT-  
6{buel(|e  
String sURL; //File URL *{vH9TO  
long nStartPos; //File Snippet Start Position X2@Ef2EkM  
long nEndPos; //File Snippet End Position 3fhY+$tq  
int nThreadID; //Thread's ID Ba@~:  
boolean bDownOver = false; //Downing is over UuWIT3W>%  
boolean bStop = false; //Stop identical  ce9P-}d  
FileAccessI fileAccessI = null; //File Access interface } Xo#/9  
["<Xh0_  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException zPa2fS8  
{ LNWS  
this.sURL = sURL; "t&=~eOe3  
this.nStartPos = nStart; -0d9,,c  
this.nEndPos = nEnd; <7VLUk}  
nThreadID = id; xeSch?}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 W|m(Jh[w]  
} 46}U+>  
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public void run() x[)-h/&Fh  
{ RJ'[m~yl5X  
while(nStartPos < nEndPos && !bStop) } +}nrJv  
{ xqzeBLU  
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try{ 1~c\J0h)d  
URL url = new URL(sURL); 7K\
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C '( Y  
httpConnection.setRequestProperty("User-Agent","NetFox"); PGJh>[s  
String sProperty = "bytes="+nStartPos+"-"; 0[l}@K?  
httpConnection.setRequestProperty("RANGE",sProperty); TQT3]h6  
Utility.log(sProperty); bO\++zOF  
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InputStream input = httpConnection.getInputStream(); |CDM(g
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//logResponseHead(httpConnection); V|MHDMD=  
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byte[] b = new byte[1024]; &SE}5
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int nRead; bgi_QB#k\  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) KVa{;zBwl  
{ E2'Wzrovlo  
nStartPos += fileAccessI.write(b,0,nRead); -U/)y:k!%  
//if(nThreadID == 1) PaI\y!f  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); TRGpE9i  
} ChTq!W  
CW+kKN  
Vc(4d-d5  
Utility.log("Thread " + nThreadID + " is over!"); .D 4G;=Q  
bDownOver = true; x"Ky_P~  
//nPos = fileAccessI.write (b,0,nRead); 8M*+ |  
} ~a([e\~  
catch(Exception e){e.printStackTrace ();} ed,A'S=d  
} T/3LJGnY  
} vTK%4=|1}!  
}ssV"5M  
`q-+r1u  
//打印回应的头信息 LeL
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public void logResponseHead(HttpURLConnection con) 
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{ l<+[l$0#  
for(int i=1;;i++) ]eKuR"ob0  
{ CM_hN>%w[  
String header=con.getHeaderFieldKey(i); 4=^_VDlpd  
if(header!=null) ~S/
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); bFG~08Z ,d  
Utility.log(header+" : "+con.getHeaderField(header)); idYB.]Y(  
else ?:\/-y)Sp  
break; F0<)8{s  
} zWEPwOlI1P  
} O`@Nl  
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Ab@G^SLX  
public void splitterStop() irAXXg  
{ \ASt&'E  
bStop = true; fkZHy|m  
} I_r@Y:5{  
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} $X#y9<bW  
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/* IEh
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**FileAccess.java |8k1Bap`z  
*//文件访问(定位，写) Kv| x -_7  
package NetFox; /Q;wz!V$  
import java.io.*; q6>eb  
+K1M&(  
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public class FileAccessI implements Serializable{ ai_ve[A  
o]<Z
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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 ;ek*2Lh  
RandomAccessFile oSavedFile; ,&_H  
long nPos; X<%D@$  
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[[$CtqLg  
public FileAccessI() throws IOException ;:6\w!fc  
{ |`LH|6/  
this("",0); N{v)pu.  
} TF8#I28AD  
^p3GT6  
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public FileAccessI(String sName,long nPos) throws IOException WWu
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{ `dZ|Ko%k  
oSavedFile = new RandomAccessFile(sName,"rw"); .TGw+E1k  
this.nPos = nPos; (DiduSJ  
oSavedFile.seek(nPos); ?@'&<o0p#  
} 4CM'I~  
RCWmdR#}V  
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public synchronized int write(byte[] b,int nStart,int nLen) >jI.$%L$  
{ |n26[=\B  
int n = -1; VRd7H.f,A6  
try{ 3k1e  
oSavedFile.write(b,nStart,nLen); dVbFMQ&  
n = nLen; 1@|+l!rYF  
} j.q}OK  
catch(IOException e) 3uuIISK  
{ m{Q #f\<  
e.printStackTrace (); @"7S$@cO  
} bT,_=7F  
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return n; cwmS4^zt8  
} ME)Tx3d  
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>bW=oTFz  
} T-] {gc  
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/* :F:1(FDP  
**SiteInfoBean.java h1_Z&VJ  
*/ }-oba_  
package NetFox; \|,| )  
I8bM-k):9R  
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public class SiteInfoBean { U,#~9  
2z-Nw <bA  
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private String sSiteURL; //Site's URL {'IO  
private String sFilePath; //Saved File's Path 11oNlgY&  
private String sFileName; //Saved File's Name `s7pM  
private int nSplitter; //Count of Splited Downloading File aw*]b.f  
flmQNrC.8  
\FsA-W\X  
public SiteInfoBean() 0/GBs~P  
{//nSplitter的缺省值为5 @lN\.O  
//default value of nSplitter is 5 \W*L9azr  
this("","","",5); ?EFRf~7JP  
} G[k3`  
yNI0Do 2  
,6>3aD1w~q  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) =z'(FP5!0  
{ c""&He4zp  
sSiteURL= sURL; mh3S?Uc  
sFilePath = sPath; \bARp z?a  
sFileName = sName; JWb +  
this.nSplitter = nSpiltter; b G:\*1T  
U`(=iyWP=  
99=~vNn  
} 23?u_?+4i  
c>LP}PGk  
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public String getSSiteURL() a3yNd  
{ 1/97_:M0~F  
return sSiteURL; <st<oR'  
} Jpapl%7v  
oP,*H6)i  
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public void setSSiteURL(String value) A)U"F&tvm  
{ v5M4Rs&t  
sSiteURL = value; h*fN]k6  
} M/W"M9u  
o|@0.H|  
=o9s?vOJ  
public String getSFilePath() s;vt2>;q+e  
{ =Kkqk  
return sFilePath; AX v q
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} uyYV_Q0~;  
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tp  
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public void setSFilePath(String value) uMQI Aapb  
{ dL0Q8d\^T  
sFilePath = value; 6&$.E! z  
} $'V^_|EL7  
0b{jox\!B  
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public String getSFileName() .)tv'V/  
{ 0f@+o}i=)  
return sFileName; uY5|Nmiu  
} JK!(\Ae.  
!)]/?&uo  
n#P>E(K  
public void setSFileName(String value) 9)VAEyv  
{ a/V,iCiH  
sFileName = value; hi"C<b.  
} 6$b=Tr=0  
;U(]#pW!t  
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public int getNSplitter() .
b";7}9{  
{ MN<LZC%$  
return nSplitter; eke[{%L  
} + +L7*1t  
i6#*y!3{  
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public void setNSplitter(int nCount) 1X)#iY  
{ Tksv7*5$  
nSplitter = nCount; ZH Q?{
"  
} ')q0VaohC  
} Wr[
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q1VKoKb6\:  
/* T~xVHk1  
**Utility.java |qX?F`  
*/ a[K&;)  
package NetFox; L/u|90)L  
+ayC0  
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public class Utility { >>{):r Z  
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@(#vg\UH  
public Utility() U,U=udsi  
{ *O$
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A"7YkOfwH  
WR #XPbk  
} lR %#R  
A$wC!P|;  
//线程睡眠 =aVvv+T
 
public static void sleep(int nSecond) 7]rIq\bM  
{ nFlN{_/  
try{ p7YYAh@x\  
Thread.sleep(nSecond); k1z`92"  
} @K]`
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catch(Exception e) EGD{nE  
{ bD,21,*z  
e.printStackTrace (); v\w*VCjoV  
} xdO3koE:  
} 7g*!6-W[  
HAH\#WE  
//日志 *<^C0:i(  
public static void log(String sMsg) b]u=Iza  
{ r%;|gIky  
System.err.println(sMsg); Y7S1^'E 3  
} dz@+ jEV  
nq_$!aB_K  
9fX0?POG  
public static void log(int sMsg) 5mAb9F8@  
{ +k6` tl~*  
System.err.println(sMsg);  C O6}D  
} 4S42h_9  
} $'\kK,=  
7Q!ksp  
&W>\Vl1  
/* f hK<P_}  
**TestMethod.java ;SXkPs3q  
*/ QuS=^,]  
package NetFox; 9po=[{Bp  
{e&fBX6;  
B9"d7E#wHF  
public class TestMethod { Sv#Ml
S>  
N-l`U(Z~P  
;y-JR$M  
public TestMethod() J0Yb_(w  
{ ///xx/weblogic60b2_win.exe rTR$\ [C  
try{ _7N?R0j^9N  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {U-
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//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); UovN"8W+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); YAXd   
fileFetch.start(); F(1E@xs  
} S<(i/5Z+  
catch(Exception e){e.printStackTrace ();} d
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.+>fD0fW7Y  
} fmYx  
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i?B<&'G  
public static void main(String[] args) T ?Om]:j  
{ 7s%D(;W_Mo  
new TestMethod(); uyEk1)HC  
} QV."ZhL5=  
} KF&8l/f  
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