http断点续传简单实现（java)

/* vVL@K,q  
**SiteFileFetch.java a')|1DnR  
*/ ZY:[ekm%4Z  
package NetFox; @^uH`mc  
import java.io.*; ['ksP-=  
import java.net.*; .;&# )l
 
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public class SiteFileFetch extends Thread { GtwT  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 8Dvazg}4  
long[] nStartPos; //开始位置 IJ/sX_k  
long[] nEndPos; //结束位置 5Vi>%5A>l  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 BATG FS&  
long nFileLength; //文件长度 _!|/ ;Nk  
boolean bFirst = true; //是否第一次取文件 nJ" '  
boolean bStop = false; //停止标志 M?;y\vS?.  
File tmpFile; //文件下载的临时信息 sdS^e`S  
DataOutputStream output; //输出到文件的输出流 ~xoF6CF  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） n#=o?!_4  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1 `KN]Nt  
{ ]%!
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siteInfoBean = bean; &hk-1y9QS  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^gFqRbuS  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1@lJonlF  
if(tmpFile.exists ()) |`;54_f  
{ O-4C+?V  
bFirst = false; /6_|]ijc  
read_nPos(); M|] "W  
} L;od6<.*m  
else kkK kf'  
{ v 36%Pj`  
nStartPos = new long[bean.getNSplitter()]; @'=Uq  
nEndPos = new long[bean.getNSplitter()]; TFuR@KaBR  
} EKp@9\XBC  
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} Zo{$  
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public void run() BAO|)~1Pd  
{ $O^v]>h  
//获得文件长度 #
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//分割文件 |$7vI&m  
//实例FileSplitterFetch vaon{2/I  
//启动FileSplitterFetch线程 $u/E\l  
//等待子线程返回 @ps1Dr4s  
try{ MJ=)v]a  
if(bFirst) !|<=ZF2  
{ R CkaJ3  
nFileLength = getFileSize(); 95<EN(oUD  
if(nFileLength == -1) *]i!fzI']  
{  RDtU43  
System.err.println("File Length is not known!"); W14Vm(`N  
} >s`J5I!  
else if(nFileLength == -2) ^`<w&I@  
{ !cGDy/|  
System.err.println("File is not access!"); 2c/Ys4/H4]  
} |7#[ (%D!  
else ?3O9eZY@  
{ 4H+Ked&Oq  
for(int i=0;i<nStartPos.length;i++) !p1qJ
[  
{ zB? V_aT  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Qeu\&%C!<  
} >><.3  
for(int i=0;i<nEndPos.length-1;i++) \a+(=s(;  
{ VACiVKk  
nEndPos = nStartPos[i+1]; .IJ_jt-^d  
} 7u[j/l,  
nEndPos[nEndPos.length-1] = nFileLength; ;=? ~ -_  
} FW"^99mrnb  
} s :`8ZBz~  

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//启动子线程 F:#J:x'  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; =YG _z^'  
for(int i=0;i<nStartPos.length;i++) 7#<c>~   
{ %okzOKKX  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), CU7F5@+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), VxzkQ}o  
nStartPos,nEndPos,i); e:AHVepj{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ez{MU@Fk  
fileSplitterFetch.start(); StI1){Wf  
} K 0hu:1l)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [Ei1~n)o  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); GjB]KA^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Kq.:G%  
nEndPos = " + nFileLength);
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// fileSplitterFetch[nPos.length-1].start(); 5b/ojr7  
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//等待子线程结束 ,^8MB.  
//int count = 0; k-*Mzm]kb  
//是否结束while循环 ouHu8)q'r  
boolean breakWhile = false; ^2]LV
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while(!bStop) ~m*,mz  
{ ]xd^%q*  
write_nPos(); _8G>&K3T<  
Utility.sleep(500); 6bBdIqGb}  
breakWhile = true; D7"p}PD>~  
+%\oO/4Fs  
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for(int i=0;i<nStartPos.length;i++) gK|R =J  
{ -=698h*  
if(!fileSplitterFetch.bDownOver) h.K
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{
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breakWhile = false; H6aM&r9}  
break; A-CUv[pM  
} $j)hNWI  
}  BGzI  
if(breakWhile) r.0oxH']  
break; _y .]3JNm  
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//count++; Ri>?KrQF%  
//if(count>4) H(Ms^8Vs~:  
// siteStop(); +CM7C%U   
} ~YCuO0t  
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System.err.println("文件下载结束！"); g<\z=H  
} b]gY~cbI8  
catch(Exception e){e.printStackTrace ();} )R{UXk3q}  
} .]Mn^2#j  
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//获得文件长度 z2/!m[U  
public long getFileSize() ;LJ3c7$@lf  
{ \Btk;ivg  
int nFileLength = -1; > 8]j   
try{ (foBp  
URL url = new URL(siteInfoBean.getSSiteURL()); UBO
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :6;e\
UE  
httpConnection.setRequestProperty("User-Agent","NetFox"); !F!3Q4  
!d9AG|  
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int responseCode=httpConnection.getResponseCode(); +
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if(responseCode>=400) TA}UY7v  
{ rVAL|0;3  
processErrorCode(responseCode); :XT?jdg  
return -2; //-2 represent access is error POU}/e!Ua  
} nq`q[KV:  
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String sHeader; g8pm2o@S  
%6 =\5>  
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for(int i=1;;i++) h5@j`{  
{ #w3ru6*W  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); r>qA $zD^  
//Utility.log(in.readLine()); Jme%  
sHeader=httpConnection.getHeaderFieldKey(i); )wf\F6jN  
if(sHeader!=null) V"d=.Hb>  
{
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if(sHeader.equals("Content-Length")) P6?0r_Y  
{ W$\X~Q'0  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (N U0Tw  
break; &^ I+s^\=  
} ^GXEJU7U  
} dhR(_  
else )bWrd$X  
break; _C+DBA  
} C*wdtEGq  
} h$h]%y  
catch(IOException e){e.printStackTrace ();} t;Wotfc[#0  
catch(Exception e){e.printStackTrace ();} x%XT2+  
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Utility.log(nFileLength); _Dq Qfc%  
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return nFileLength; {fG|_+tl3o  
} cgNt_8qC  
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//保存下载信息（文件指针位置） Tt6{WDscZ  
private void write_nPos() IrO+5w  
{ wA0eG@xi)  
try{ (UW6F4:$  
output = new DataOutputStream(new FileOutputStream(tmpFile)); m
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output.writeInt(nStartPos.length); uZ[/%GTX{)  
for(int i=0;i<nStartPos.length;i++) dIK{MA  
{ mmN|F
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// output.writeLong(nPos); )<LI%dQ:'l  
output.writeLong(fileSplitterFetch.nStartPos); Nu. (viQ}  
output.writeLong(fileSplitterFetch.nEndPos); rUFFF'm\*a  
} .;%q/hP  
output.close(); ?cBO6^  
} PdM*5g4  
catch(IOException e){e.printStackTrace ();} /W9 &Ke  
catch(Exception e){e.printStackTrace ();} rU*q@y Px  
} t,?,F4j
 
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//读取保存的下载信息（文件指针位置） #O6 EP#B  
private void read_nPos() nhT;b,G.Z  
{ Gx;xj0-"  
try{ Okoo(dfM
 
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,7I},sZj  
int nCount = input.readInt(); 4zX=3iBt  
nStartPos = new long[nCount]; \A
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nEndPos = new long[nCount]; y*(_\\
 
for(int i=0;i<nStartPos.length;i++) wEK%T P4  
{ z1}1*F"  
nStartPos = input.readLong(); )DRkS,I  
nEndPos = input.readLong(); R%W@~o\p]  
} ,M{Q}:$+4  
input.close(); W1<.OO\J  
} p~FQcW'a~  
catch(IOException e){e.printStackTrace ();} #hZQ>zcF  
catch(Exception e){e.printStackTrace ();} A~XOK;sB  
} m
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private void processErrorCode(int nErrorCode) \{:%v#ZZ  
{ !+=Zjm4L  
System.err.println("Error Code : " + nErrorCode); g?gq
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} Q;Q%SI`yT  
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n{L:MT9TD  
//停止文件下载 NA=#>f+U%  
public void siteStop() ]ZDTn  
{ /=q.tDH=I  
bStop = true; ]
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for(int i=0;i<nStartPos.length;i++) **.:)  
fileSplitterFetch.splitterStop(); <_>.!9q  
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} ?Q;kZmQl  
} %N>\:85?  
//负责部分文件的抓取 qP&byEs"  
**FileSplitterFetch.java kq>GMUl~@  
*/ ,%[LwmET  
package NetFox; C`3V=BB  
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import java.io.*; n}0za#G  
import java.net.*; _O"L1Let  
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public class FileSplitterFetch extends Thread { D DQs42[  
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String sURL; //File URL Q,D0kS P  
long nStartPos; //File Snippet Start Position lxo.,n)  
long nEndPos; //File Snippet End Position kkT3wP  
int nThreadID; //Thread's ID sfyBw  
boolean bDownOver = false; //Downing is over 7AI3|Ts]p  
boolean bStop = false; //Stop identical ]/LWrQD
  
FileAccessI fileAccessI = null; //File Access interface ,GP!fs
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException =Na/3\^WP  
{ {a]pF.^kf  
this.sURL = sURL; S|~i>  
this.nStartPos = nStart; {5U1`
>  
this.nEndPos = nEnd; O;UiYrXU  
nThreadID = id; PP!l  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &}>|5>cJu  
} anK[P'Y  
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public void run() Y_$^:LG  
{ y>@v>S  
while(nStartPos < nEndPos && !bStop) be&6kG  
{ Rl y jOf{0  
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try{ 6lN?)<uQ  
URL url = new URL(sURL); |)28=Z|Z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); W8Ke1(ws&  
httpConnection.setRequestProperty("User-Agent","NetFox"); uG2Xkj  
String sProperty = "bytes="+nStartPos+"-"; jAA'hA  
httpConnection.setRequestProperty("RANGE",sProperty); sVE>=0TVP  
Utility.log(sProperty); <+<)xwOQ ]  
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InputStream input = httpConnection.getInputStream(); enPzy:C  
//logResponseHead(httpConnection); M7`UoTc+>d  
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byte[] b = new byte[1024]; (xucZ  
int nRead; ;~}-AI-  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) CHQ{+?#  
{ t9-_a5>E\}  
nStartPos += fileAccessI.write(b,0,nRead); C*"Rd   
//if(nThreadID == 1) $~ pr+Ei  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Rg%R/p)C  
} ~z\pI|DQ  
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Utility.log("Thread " + nThreadID + " is over!"); e7Yb=/F  
bDownOver = true; [37f#p  
//nPos = fileAccessI.write (b,0,nRead); 7yY1
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} Zr
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catch(Exception e){e.printStackTrace ();} >g5T;NgH9  
} &>d:ewM\  
} ,m #@%fa  
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//打印回应的头信息 )OARO  
public void logResponseHead(HttpURLConnection con) X;K8,A7`  
{ B|$\

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for(int i=1;;i++) 8r7/IGFg  
{ [i,5>YIk
 
String header=con.getHeaderFieldKey(i); Up]VU9z  
if(header!=null) }0k"SwX  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); x]yHBc  
Utility.log(header+" : "+con.getHeaderField(header)); r?Ev.m  
else X}65\6  
break; S&4w`hdD>~  
} PO=ZxG
  
} ~N
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public void splitterStop() %xH
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{ ~2, wI<Nz  
bStop = true; 4YU1Kr4  
} 30gZ_8C>}  
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} 7|{%CckN  
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/* % @^VrhS  
**FileAccess.java ;GSfN  
*//文件访问(定位，写) {ra Esb-X  
package NetFox; @BB,i /  
import java.io.*; X*p:&=o  
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public class FileAccessI implements Serializable{ U_zpLpm^  
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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 iz,q8}/(  
RandomAccessFile oSavedFile; -*]9Ma<wa  
long nPos; ^/5E773  
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public FileAccessI() throws IOException `P)64So-1  
{ w4&v( m  
this("",0); |'l* 
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} N;Gf,pE  
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public FileAccessI(String sName,long nPos) throws IOException (WU~e!}  
{ A$Jn3Xd~!  
oSavedFile = new RandomAccessFile(sName,"rw"); N?u2,h-  
this.nPos = nPos; Pq_ApUZa  
oSavedFile.seek(nPos); s-YV_  
} ",,qFM!  
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public synchronized int write(byte[] b,int nStart,int nLen) b ffml  
{ & /FA>  
int n = -1; [4(A458H  
try{ -:1Gr8  
oSavedFile.write(b,nStart,nLen); $@ #G+QQ_  
n = nLen; 6`PGV+3j  
} q~A|R  
catch(IOException e) ~'YSVx& )  
{ looPO:bo^  
e.printStackTrace (); zw;(:fgY#  
} ]r{#268  
z%-"'Y]  
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return n; [}g5Z=l  
} *{n,4d\..  

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} ,Y/>*,J  
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/* dodz|5o%  
**SiteInfoBean.java i3\oy`GJ  
*/ UgBY ){<  
package NetFox; Q0cf]  
<@2?2l+`X  
J+Y|# U  
public class SiteInfoBean { ToCfLJ?{  
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private String sSiteURL; //Site's URL p{_O*bo  
private String sFilePath; //Saved File's Path 2FtEt+A+'  
private String sFileName; //Saved File's Name +hY
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private int nSplitter; //Count of Splited Downloading File t5[JN:an  
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public SiteInfoBean()  
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{//nSplitter的缺省值为5 k$m
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//default value of nSplitter is 5 Lgw@y!Llij  
this("","","",5); D.JVEKLkU  
} 5_T>HHR6  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) CHSD8D  
{ y")>"8H  
sSiteURL= sURL; [
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sFilePath = sPath; %Y[/Ucdm  
sFileName = sName; Rf$6}F  
this.nSplitter = nSpiltter; w'j]Y%  
v\T1,Z@N^  
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} um4zLsd#v  
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public String getSSiteURL() 0([jD25J!  
{ eJdQ7g[>  
return sSiteURL; .=<pU k 3G  
} "TCbO`mg  
!I  P*  
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public void setSSiteURL(String value) 1Vvx@1  
{ B(NL3WJ  
sSiteURL = value; Y&%0 eI!  
} X0L{#U  
JG$J,!.\  
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public String getSFilePath() /v<8x?=  
{ ZPFTNwf  
return sFilePath; l0o_C#"<S  
} e;\c=J,eE  
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public void setSFilePath(String value) 4H'&5  
{ G*V 7*KC  
sFilePath = value; dg<fUQ  
} SpQ6A]M gm  
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public String getSFileName() EPf
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{ wEqCuhZ  
return sFileName; Z0^do  
} j(N9%/4u  
G(e?]{(  


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public void setSFileName(String value) Nzt1JHRS  
{ Wb$bCR#?<  
sFileName = value; 1Tkz!  
} ".=EAXVU  
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public int getNSplitter() AG%aH=TKp  
{ X[}%iEWzT  
return nSplitter; P@ u%{  
} B(U`Zd  
[sRQd;+  
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public void setNSplitter(int nCount) pj`-T"Q  
{ =<icHt6s  
nSplitter = nCount; stScz#!  
} =XB)sC%  
} bv0 %{u&  
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/* h !1c(UR  
**Utility.java dE~ns ,+  
*/ a;sZNUSn  
package NetFox; >F v8 -  
nEYJ?_55  
5;*C0m2%i  
public class Utility { xUUp?]9y  
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public Utility() $Z4p$o dk  
{ ]Yy S
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} }Z|a?J@CZm  
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//线程睡眠 ()Z$j,2  
public static void sleep(int nSecond) $A,=z  
{ l`k3!EZDS  
try{ n9%rjS$  
Thread.sleep(nSecond); cVMTT]cj1  
} \[BnAgsF  
catch(Exception e) sq%f%?(V  
{ *,(`%b[  
e.printStackTrace (); S/4kfsN  
} Kt-@a%O0  
} $FoNEr&q  
\Z$*8z=  
//日志 eP)RP6ON{  
public static void log(String sMsg) ZO,]h9?4  
{ @RC_Ie=#)  
System.err.println(sMsg); eNNK;xXe#  
} `?)i/jko"  
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public static void log(int sMsg) j<c_*^/'9  
{ 8L#sg^1V  
System.err.println(sMsg); {0|^F!1z  
} "}n]0 >J  
} *]LM2
J  
[W2k#-%G  
#q\C"N5ip  
/* g {00
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**TestMethod.java i}!CY@sW  
*/ nPKj%g3h  
package NetFox; U@9n7F  
c9Cp!.#*E  
*+b[v7  
public class TestMethod { j9Lc2'  
<_D+'[  
_^KD&t%!+y  
public TestMethod() @=$;^}JS|  
{ ///xx/weblogic60b2_win.exe Eq|_>f@@8  
try{ Agl[Z>Q  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); t({:TQ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); GR"Jk[W9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); G,J$lTX  
fileFetch.start(); /V,:gLpQ  
} V< J~:b1V  
catch(Exception e){e.printStackTrace ();} spJB6n(  
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} $Q62 7  
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rt f}4.  
public static void main(String[] args) K(hqDif*6  
{ mp}ZHufG  
new TestMethod(); !bQ5CB  
} *C$ W^u5h  
} <CeDIX t  
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