http断点续传简单实现（java)

/* #JL&]Z+X6  
**SiteFileFetch.java `'xQ6Sy  
*/ yD3bl%uZ
 
package NetFox; -uv 9(r\P  
import java.io.*; BaWQ<T8p8  
import java.net.*; Q? <-`7  
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i
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public class SiteFileFetch extends Thread { 9?u9wuH  
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SiteInfoBean siteInfoBean = null; //文件信息Bean BKE\SWu  
long[] nStartPos; //开始位置 <=;H[} e  
long[] nEndPos; //结束位置 hFsA_x+L;  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 D'7A2f  
long nFileLength; //文件长度 C6K|:IK{  
boolean bFirst = true; //是否第一次取文件 z>cIiprX  
boolean bStop = false; //停止标志 Y%78>-2L  
File tmpFile; //文件下载的临时信息 V*6l6-y~Ih  
DataOutputStream output; //输出到文件的输出流 tt+>8rxF:;  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） "%{,T  
public SiteFileFetch(SiteInfoBean bean) throws IOException D ?Nd;[  
{ FjD,8^SQW  
siteInfoBean = bean; +dqk6RE  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); J"%8:pL  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~A^E  
if(tmpFile.exists ()) !OPSSP]-  
{ W3D
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bFirst = false; 7V~ "x&Eu  
read_nPos(); Ap11b|v  
} tlDYk  
else Yuwc$Qp)  
{ f"vk# 3  
nStartPos = new long[bean.getNSplitter()]; {/-y>sm  
nEndPos = new long[bean.getNSplitter()]; +J"'  'cZ  
} LMAmpVo  
X.s*>'  
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} X6Un;UL  
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public void run() Y^QKp"  
{ tC^ 1}  
//获得文件长度 ypH8QfxLTr  
//分割文件 zm3-C%:Bw  
//实例FileSplitterFetch w'A tf  
//启动FileSplitterFetch线程 -^yXLa;D  
//等待子线程返回 +fM&su=wl  
try{ P^"R4T  
if(bFirst) uM<|@`&b  
{ gc##V]OD  
nFileLength = getFileSize(); 7skljw(  
if(nFileLength == -1) bMsECA&  
{ W]_g4,T>  
System.err.println("File Length is not known!"); !K[/L< Kv  
} {-HDkG' 8  
else if(nFileLength == -2) f27)v(EJ  
{ IhE9snJ[  
System.err.println("File is not access!"); |k6Ox*  
} RAV^D.  
else FqwIJ|ct  
{ w
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for(int i=0;i<nStartPos.length;i++) z$|;-u|  
{ X]!D;7^  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); gXt O*Rfqk  
} ?KB@Zm+#~  
for(int i=0;i<nEndPos.length-1;i++) fJ
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{ Nt~x&s  
nEndPos = nStartPos[i+1]; +%XnMl  
} X'x3esw w  
nEndPos[nEndPos.length-1] = nFileLength; 3CM^j<9  
} 0 _A23.Y  
} L+.H z&*@  
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//启动子线程 q jz3<`7-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; W pN.]x  
for(int i=0;i<nStartPos.length;i++) `*aBRwvK~  
{ PO o%^'(  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uE`r/=4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), d2~l4IL)~  
nStartPos,nEndPos,i); OPuj|%Wgw  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); X?/Lz;,&  
fileSplitterFetch.start(); Jf_%<\ O  
} Ie@Jb{x  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), % 5z gd>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); (.?ZKL  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", GoIQ>n
 
nEndPos = " + nFileLength); : @6mFTV  
// fileSplitterFetch[nPos.length-1].start(); ?:igumeYX  
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//等待子线程结束 ~
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//int count = 0; ',)7GY/n~  
//是否结束while循环 %;|
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boolean breakWhile = false; h5GU9M  
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while(!bStop) BzN@gQo  
{ y=Q!-~5|fF  
write_nPos(); C6jR=@42Q  
Utility.sleep(500); A@$kLex  
breakWhile = true; EzpFOqJG  
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for(int i=0;i<nStartPos.length;i++) (D7$$!}  
{ 2K{6iw"h  
if(!fileSplitterFetch.bDownOver) tFM$#JN  
{ <9eu1^g  
breakWhile = false; Vrkf(E3_V  
break; 42+#<U7T  
} [6tSYUZs  
} )T|L,Lp  
if(breakWhile) XP
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break; l]6%lud8_  
t ls60h  
T .n4TmF  
//count++; :/N+;- 18  
//if(count>4) T!|=El>  
// siteStop(); t ^SzqB  
} =,V|OfW  
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j !H^-d}q  
System.err.println("文件下载结束！"); iG<Som  
} W+=o&V  
catch(Exception e){e.printStackTrace ();} D Ml?o:l  
} 'T8
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//获得文件长度 >I"V],d!6  
public long getFileSize() kg97S  
{ PnYBy| yl  
int nFileLength = -1; g(E"4M@t!  
try{ /)3Lnn
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URL url = new URL(siteInfoBean.getSSiteURL()); r'7LR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]9 w76Z  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5*-3? <)e  
, X{>  
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int responseCode=httpConnection.getResponseCode(); h*i9m o  
if(responseCode>=400) p{$p $/A  
{ ca<"  
processErrorCode(responseCode); jM)C4ii.-$  
return -2; //-2 represent access is error '@nbqM  
} 4,p;Km&  
*# {z3{+  
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String sHeader; zbkMFD.{y  
l@Z6do  
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for(int i=1;;i++) 5s{j=.O  
{ _QOZsEe  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); "/{RhY<  
//Utility.log(in.readLine()); !~i' -4]  
sHeader=httpConnection.getHeaderFieldKey(i); (5L-G{4  
if(sHeader!=null) OX]V)QHVZ  
{ a?h*eAAc.  
if(sHeader.equals("Content-Length")) nk"NmIf  
{ rh*sbZ68>E  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); dq;|?ESP  
break; nuQ]8-,  
} g`^X#-!(  
} HvwYm.$zE  
else 2-*V=El  
break; ,8'>R@o  
} W*DVi_\$y  
} Fzlozx1y[  
catch(IOException e){e.printStackTrace ();} ;h=*!7:  
catch(Exception e){e.printStackTrace ();} BimjQ;jtI  
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Utility.log(nFileLength); NH<gU_s8{9  
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return nFileLength; :,12")N  
} d$ACDX
2  
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//保存下载信息（文件指针位置） ~[o4a
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private void write_nPos() }T^cEfX  
{ '7Nr8D4L  
try{ moj]j`P5a  
output = new DataOutputStream(new FileOutputStream(tmpFile)); WF&[HKOy/  
output.writeInt(nStartPos.length); +6$g!S5{  
for(int i=0;i<nStartPos.length;i++) {#P`^g  
{ MTER(L  
// output.writeLong(nPos); JCcZuwu[  
output.writeLong(fileSplitterFetch.nStartPos); 3ya1'qUC  
output.writeLong(fileSplitterFetch.nEndPos); >Iewx G
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} G|w=ez  
output.close(); up
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} z{"2S="  
catch(IOException e){e.printStackTrace ();} .o1^O
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catch(Exception e){e.printStackTrace ();} r"2V  
} \I-#1M  
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//读取保存的下载信息（文件指针位置） 8[CB>-9  
private void read_nPos() aV o;~h~  
{ jN-vY<?h]  
try{ u<q :$  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); [XRCLi}  
int nCount = input.readInt(); ?&LZB}1R  
nStartPos = new long[nCount]; $WYbm}j  
nEndPos = new long[nCount]; 9=w|)p )  
for(int i=0;i<nStartPos.length;i++) {8,<ZZ_  
{ jV#ahNq;  
nStartPos = input.readLong(); My
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nEndPos = input.readLong(); \T]EZ'+O  
} F/m^?{==~*  
input.close();  nVu&/  
} gj\)CBOv  
catch(IOException e){e.printStackTrace ();} ;Sd\VR  
catch(Exception e){e.printStackTrace ();} 2)#K+O3c  
} ~^
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private void processErrorCode(int nErrorCode) 2oa#0`{  
{ JGC=(;  
System.err.println("Error Code : " + nErrorCode); Am8x74?  
} I -Xlx<  
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//停止文件下载 j-CnT)W<  
public void siteStop() Lb{e,JH  
{ RH}A  
bStop = true; d!KsNkk  
for(int i=0;i<nStartPos.length;i++)
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fileSplitterFetch.splitterStop(); ^qCkt1C-M  
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} T081G`li  
} TF2>
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//负责部分文件的抓取 2=?tJ2E  
**FileSplitterFetch.java |AlR^N  
*/ Lokl2o`  
package NetFox; x^"ES%*  
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import java.io.*; ,>t69 Ad  
import java.net.*; 7?B.0>$3>V  
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public class FileSplitterFetch extends Thread { A2}Rl%+X]6  
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String sURL; //File URL SXao|{?O  
long nStartPos; //File Snippet Start Position SuZ&vqS  
long nEndPos; //File Snippet End Position xEuN   
int nThreadID; //Thread's ID SI:U0gUc  
boolean bDownOver = false; //Downing is over b3wM;jv  
boolean bStop = false; //Stop identical E;21?`x5  
FileAccessI fileAccessI = null; //File Access interface IVlf=k  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException RE.r4uOJg  
{ RzhWD^bB  
this.sURL = sURL; 2oJb)CB  
this.nStartPos = nStart; |[9?ma  
this.nEndPos = nEnd; 65ly2gl  
nThreadID = id; GJX4KA8J  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Y~az!8j;Z  
} yIOLs}!SF  
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public void run() ^|aNG`|O  
{ NgHpIonC  
while(nStartPos < nEndPos && !bStop) ,>u=gA&}  
{ VpSEVd:n  
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try{ PPa^o8jd  
URL url = new URL(sURL); +e'X;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7IW> >RBF  
httpConnection.setRequestProperty("User-Agent","NetFox"); 71O3O7  
String sProperty = "bytes="+nStartPos+"-"; E:FO_R(Xq  
httpConnection.setRequestProperty("RANGE",sProperty); 8Y#bN*!  
Utility.log(sProperty); %w7m\nw@  
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InputStream input = httpConnection.getInputStream(); ^n9a" qz  
//logResponseHead(httpConnection); ,-@5NY1q  
7UKYmJk.  
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byte[] b = new byte[1024]; x5OC;OQc  
int nRead; 1kmQX+f
  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) L,~MicgV  
{ w>qCg XU3  
nStartPos += fileAccessI.write(b,0,nRead); (S oo<.9~  
//if(nThreadID == 1) Y
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /BpxKh2p  
} 1TjZ#yP%1  
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Utility.log("Thread " + nThreadID + " is over!"); }E;F)=E  
bDownOver = true; S5_t1wqBJ  
//nPos = fileAccessI.write (b,0,nRead); $}R$t-  
} YsP/p-  
catch(Exception e){e.printStackTrace ();} !8*McOI  
} 'L{p,  
} gDCOLDM  
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//打印回应的头信息 5h8o4  
public void logResponseHead(HttpURLConnection con) -(>qu.[8=  
{ xhw-2dl*H  
for(int i=1;;i++) xMI+5b8  
{ 0Q~@F3N-\>  
String header=con.getHeaderFieldKey(i); O"*`'D|hK  
if(header!=null) ni6r{eS
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); 
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Utility.log(header+" : "+con.getHeaderField(header)); $%PVJs  
else \cQ .|S  
break; R#(G%66   
} 4DLq}v  
} n|i
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public void splitterStop() lJ{V
  
{ dB;3.<S=  
bStop = true; "&lN\&:  
} Z0ReWrl;`  
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} J!h^egP  
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/* 9vI]LfP  
**FileAccess.java ^bUxLa[.  
*//文件访问(定位，写)
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package NetFox; 7>i2OBkAhB  
import java.io.*; ;GsQR+en
 
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public class FileAccessI implements Serializable{ aMK~1]Cx  
5HlWfD  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ksWSMxm  
RandomAccessFile oSavedFile; [vTMS2  
long nPos; C+%K6/J(  
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public FileAccessI() throws IOException @Bs0Avj.  
{ v27Ja .tA  
this("",0); 7@~tVxB;  
} R1ktj  
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&~-~5B|3"  
public FileAccessI(String sName,long nPos) throws IOException 1S$h<RIPAc  
{ 2cf' ,cv@8  
oSavedFile = new RandomAccessFile(sName,"rw"); 2~c~{ jl\  
this.nPos = nPos; ?Zz'|.l@  
oSavedFile.seek(nPos); ]gEhE  
} $-vo}k%M  
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public synchronized int write(byte[] b,int nStart,int nLen) K`k'}(vj  
{ nWWM2v  
int n = -1; 8`v$liH  
try{ H?yE3w  
oSavedFile.write(b,nStart,nLen); %<Q*Jf  
n = nLen; 27 GhE  
} cA;js;x@  
catch(IOException e) )`HA::  
{ Vhg1/EgUr  
e.printStackTrace (); mBk5+KyT  
} !/I0i8T  
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return n; Llz['"m  
} HDIk9WC^  
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} q'S =Eav8  
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/* .36^[Jsz":  
**SiteInfoBean.java &ak6zM  
*/ gPEqjj  
package NetFox; y,m2(V  
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6)*xU|fU  
public class SiteInfoBean { $=aI"(3&  
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private String sSiteURL; //Site's URL $L}aQlA1JM  
private String sFilePath; //Saved File's Path &ITuyGmF  
private String sFileName; //Saved File's Name g9mG`f  
private int nSplitter; //Count of Splited Downloading File l]#!+@  
c^.l2Q!  
=-jD~rN4;P  
public SiteInfoBean() N$alUx*  
{//nSplitter的缺省值为5 O/OiQ^T  
//default value of nSplitter is 5 wH6u5*$p  
this("","","",5); ]=&L_(34  
} z,f=}t[.Y  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) (ku5WWJ  
{ ;vp\YIeX1  
sSiteURL= sURL; SUdm 0y  
sFilePath = sPath; >Da~Q WW|  
sFileName = sName; rVryt<2:@r  
this.nSplitter = nSpiltter; ZX.TqvK/r  
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} V1bh|+o9  
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public String getSSiteURL() 8X7{vN_3K  
{ #hxyOq,  
return sSiteURL; &0v.E"0<
 
} M}F~_S0h  
}ot"Sx\.  
d@kc[WLD^  
public void setSSiteURL(String value) FJS'G^  
{ pP/@  
sSiteURL = value;  <!'M} s  
} x:z0EYL  
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public String getSFilePath() .p@N:)W6  
{ cCdX0@hY  
return sFilePath; }NmNanW^  
} |X(2Zv^O  
tIZ~^*'  
:@.
;  
public void setSFilePath(String value) WS0JS'  
{ TT}]wZ  
sFilePath = value; p2pAvlNoF  
} JWHSnu!  
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public String getSFileName() |:q/Dt@  
{ r6.N4eW.L  
return sFileName; 4\2V9F{s  
} vzR=>0#  
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public void setSFileName(String value) j4.&l3  
{ wD9a#AgEd  
sFileName = value; KS<Jv;  
} xAdq+$><  
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public int getNSplitter() Wk7WK` >i  
{ #G;X' BN  
return nSplitter; q~Jq/E"f  
} d/
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p+w8$8)  
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public void setNSplitter(int nCount) O.+9,4A(  
{ $RO$}!  
nSplitter = nCount; trYTs,KV  
} z'MS#6|}  
} _"N\b%CkO  
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/* "QY1.:o<(  
**Utility.java 9]yW_]P  
*/ >S#ul?  
package NetFox;  tFh|V pB  
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public class Utility { N}Vn;29  
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public Utility() >L>+2z  
{ Y7Gs7  
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')TPF{\#  
} *gqSWQ  
3Sh+u>w  
//线程睡眠 _<Dt z  
public static void sleep(int nSecond) 2
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1  
{ GjQfi'vCk  
try{ %}qbkkZ  
Thread.sleep(nSecond); 8l)  
} j6>tH"i  
catch(Exception e) %xlpB75N4N  
{ 1y[B[\  
e.printStackTrace (); HOPqxI(k  
} !: us!s  
} 5K.+CO<  
Wmz`&nsn[  
//日志 Fdt}..H%  
public static void log(String sMsg) )"u:ytK{  
{ V2 `> ]/|  
System.err.println(sMsg); n9oR)&:o  
} b|?;h21rG  
]PS\#I}  
 (_+;R  
public static void log(int sMsg) &8?`<   
{ Spj9H?m  
System.err.println(sMsg); kQIw/@WC  
} IN!02`H  
} OyVm(%Z   
b X,Siz:F  
[.cq{6-
  
/* O%JSViPw  
**TestMethod.java t4K56H.L?  
*/ C0m\SNR  
package NetFox; x ^vt; $  
<r\I"z$  
p:[LnL  
public class TestMethod { DeQDH5X"  
MCy~@)-IN  
4rp6 C/i  
public TestMethod() ]VjLKFb~U  
{ ///xx/weblogic60b2_win.exe _z"o1`{w  
try{ <G
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); L;)v&a7[P  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); jD9lz-Y@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); uxDLDA$;  
fileFetch.start(); a$}6:E  
} #PAU'u 3{/  
catch(Exception e){e.printStackTrace ();} (!</%^ZI  
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} uiMIz?+  
=5s$qb?#  
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public static void main(String[] args) nCaLdj?  
{ 5*j:K&R-.K  
new TestMethod(); NMXM[Ukb
 
} ]w22@s  
} r{ @
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