http断点续传简单实现（java)

/* )zAATBb4.  
**SiteFileFetch.java 9r=yfc!cS  
*/ 34:Y_*  
package NetFox; !t!'  
import java.io.*; mTBSntZx  
import java.net.*; #7Jvk_r9Y  
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public class SiteFileFetch extends Thread { pF<KhE*V  
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SiteInfoBean siteInfoBean = null; //文件信息Bean {xu~Dx  
long[] nStartPos; //开始位置 o7kQ&w  
long[] nEndPos; //结束位置 #ja6nt8GC  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 J*D3=5&  
long nFileLength; //文件长度 s)~Wcp'+M:  
boolean bFirst = true; //是否第一次取文件 $J9/AFzO"  
boolean bStop = false; //停止标志 4Hq6nT/  
File tmpFile; //文件下载的临时信息 bPA1>p7  
DataOutputStream output; //输出到文件的输出流 BT|n+Y[  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &xE+PfX  
public SiteFileFetch(SiteInfoBean bean) throws IOException s8+{##"1 q  
{ EYR%u'&7'  
siteInfoBean = bean; bltZQI|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9S/X,|i  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); x\b+B  
if(tmpFile.exists ()) siz:YRur  
{ (sp{.bU  
bFirst = false; ;7U"wI_~c  
read_nPos(); 4vyJ<b  
} )^7- qy  
else _#y=T20'3  
{ <,</ Ge  
nStartPos = new long[bean.getNSplitter()]; 0)Q*u  
nEndPos = new long[bean.getNSplitter()]; &I7T?  
} H,Yrk(O-  
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} iJb-F*_y  
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public void run() (".WJXB\  
{ 8V@\$4@b!#  
//获得文件长度 
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//分割文件 [[
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//实例FileSplitterFetch UUEbtZH;  
//启动FileSplitterFetch线程 j"9Zaq_  
//等待子线程返回 1O+$"5H  
try{ l 9bg  
if(bFirst) PBb'`PV  
{ \OVw  
nFileLength = getFileSize(); :~\ y
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if(nFileLength == -1) p!7(ayu  
{ S4D~`"4$/  
System.err.println("File Length is not known!"); 8X)1bNGqhe  
} ,lQfsntk'  
else if(nFileLength == -2) cB_3~=fV  
{ 9 =D13s(C  
System.err.println("File is not access!"); 9d8U
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} fKNDl\SD  
else N >k,"=N/  
{ MrhJk  
for(int i=0;i<nStartPos.length;i++) Hh'o:j(^  
{ vPM2cc/o  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); -5Aqf\  
} +t}<e(  
for(int i=0;i<nEndPos.length-1;i++) <5npVm  
{ T#ehJq 5  
nEndPos = nStartPos[i+1]; [='<K  
} F32U;fp3  
nEndPos[nEndPos.length-1] = nFileLength; 0pA>w8mh  
} B+lnxr0t  
} gsVm)mkd  

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//启动子线程 $o^N_`l  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; v2}>/b)  
for(int i=0;i<nStartPos.length;i++) <zp|i#~  
{ H;Gd
  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bix}#M  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), SO
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nStartPos,nEndPos,i); ZqfoO!Ta  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~"22X`;h[G  
fileSplitterFetch.start(); Eg0qY\'  
} e89IT*  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6&L8{P  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7vEZb.~4z  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 79}Qj7  
nEndPos = " + nFileLength); .`+N+B(4  
// fileSplitterFetch[nPos.length-1].start(); {oRR]>  
Gt;U9k|i  
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//等待子线程结束 yD(v_J*  
//int count = 0; _Sult;y"u  
//是否结束while循环 J" U!j  
boolean breakWhile = false; o_?A^u  
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while(!bStop) V?4G~~F  
{ V#\iO  
write_nPos(); g42f*~l  
Utility.sleep(500); uEdeA'*^  
breakWhile = true; /^b=| +Do  
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for(int i=0;i<nStartPos.length;i++) R![1\Yv&
 
{ MXynv";<H  
if(!fileSplitterFetch.bDownOver) z5 :53,`D'  
{ xB,(!0{`  
breakWhile = false; $<d3g:  
break; WGI4DzKa  
} )Qc>NF0  
} v Yw$m#@  
if(breakWhile) #&&  
break; Kr74|W=  
rB.LG'GG]  
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//count++; ])mYE }g  
//if(count>4) 5j#XNc)"  
// siteStop(); dPyZzMes=  
} G$CI~0Se:  
C%;J9(r  
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System.err.println("文件下载结束！"); }+BbwBm&  
} )X5en=[)O  
catch(Exception e){e.printStackTrace ();} (
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} fC!+"g55  
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u;=a=>05IR  
//获得文件长度 _A=Pr_kN  
public long getFileSize() !KmSLr7xU  
{ g:fzf>oQ>p  
int nFileLength = -1; H(ds  
try{ ~19&s
~  
URL url = new URL(siteInfoBean.getSSiteURL()); 9X
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?V(h@T  
httpConnection.setRequestProperty("User-Agent","NetFox"); $s!2D"wl n  
>l(|c9OWM  
8aa`0X/6  
int responseCode=httpConnection.getResponseCode(); #H&`wMZZ:  
if(responseCode>=400) j4!oBSp  
{ k{.`=j  
processErrorCode(responseCode); >kG: MJj  
return -2; //-2 represent access is error zM++Z*  
} Ap9 %5:]  
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String sHeader; p|VgtQ/)%  
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for(int i=1;;i++) m7NrS?7  
{ p^?]xD(  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); jt4c*0z  
//Utility.log(in.readLine()); <hmRr  
sHeader=httpConnection.getHeaderFieldKey(i); KcF#c_f   
if(sHeader!=null) =Vi>?fWpn=  
{ AJR`ohh  
if(sHeader.equals("Content-Length")) cj9<!"6  
{ FdMxw*}  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )L%[(iI,x  
break; 1bpjj'2%x  
} wsyAq'%L  
} b%D}mxbS  
else ky|Py  
break; h-=lZ~W~  
} t.= 1<Ed  
}
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catch(IOException e){e.printStackTrace ();} 'I1^70bB  
catch(Exception e){e.printStackTrace ();} fv?vfI+m  
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Utility.log(nFileLength); SKrkB~%z  
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return nFileLength; /GMT  
} Mh*^@_h?  
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//保存下载信息（文件指针位置） rT{+ h}vO  
private void write_nPos() Z{spo=  
{ [{cMEV&  
try{ =#sr4T  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Uh8c!CA8:\  
output.writeInt(nStartPos.length); "[p-I
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for(int i=0;i<nStartPos.length;i++) \1cJ?/$_Of  
{ ?(P3ZTk?.  
// output.writeLong(nPos); :igURr
  
output.writeLong(fileSplitterFetch.nStartPos); V j"B/@  
output.writeLong(fileSplitterFetch.nEndPos); j SXVLyz  
} y%=t((.Z  
output.close(); Cz]NSG5  
} )%=oJ!)  
catch(IOException e){e.printStackTrace ();} 8sGaq [  
catch(Exception e){e.printStackTrace ();} *:hHlH* t1  
} .Pi8c[  
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YQ#o3sjs  
//读取保存的下载信息（文件指针位置） TEt+At`]  
private void read_nPos() %W:]OPURK  
{ 8^ezqd`  
try{ \oc*  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); l8Ks{(wh
 
int nCount = input.readInt(); QeZK&^W  
nStartPos = new long[nCount]; v35=4>Y  
nEndPos = new long[nCount]; Ht!]%  
for(int i=0;i<nStartPos.length;i++) S1oP_A[|  
{ Qfd4")zhG  
nStartPos = input.readLong(); 13KfI  
nEndPos = input.readLong(); Jx_BjkF  
} s6| S#  
input.close(); y?*4SLy
 
} MH=;[| N  
catch(IOException e){e.printStackTrace ();} ^i!6q9<{e  
catch(Exception e){e.printStackTrace ();} o2#_CdU  
} 1Xj>kE:  
*aT\V64  

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private void processErrorCode(int nErrorCode) vS_Ji<W~E  
{ v"N%w1`.e  
System.err.println("Error Code : " + nErrorCode); qL?`l;+  
} |H7f@b]Sk  
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y o |"-  
//停止文件下载 sAec*Q(R  
public void siteStop() }Uc)i
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{ >p|tIST  
bStop = true; eod-N}o  
for(int i=0;i<nStartPos.length;i++) % A8dO+W  
fileSplitterFetch.splitterStop(); xgV(0H}Mf  
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} QKt[Kte  
} EvQMt0[?EW  
//负责部分文件的抓取 zUCtH*  
**FileSplitterFetch.java c^s%t:)K  
*/ Wz]ny3K[.  
package NetFox; 896oz>  
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#`(-Oj2hH  
import java.io.*; MX\v2["FoV  
import java.net.*; zv}3Sl@  
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:kz"Wya.  
public class FileSplitterFetch extends Thread { (h3f$  
krI@N}OU  
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String sURL; //File URL EmO{lCENk  
long nStartPos; //File Snippet Start Position @0{vA\  
long nEndPos; //File Snippet End Position =2rkaBFC  
int nThreadID; //Thread's ID 1?}5.*j<  
boolean bDownOver = false; //Downing is over |}Wm,J  
boolean bStop = false; //Stop identical _cw~N p  
FileAccessI fileAccessI = null; //File Access interface /3mt=1/~{B  
aH!2zC\:T  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ZN `D!e6  
{ 9C_Vb39::$  
this.sURL = sURL; ;#jE??E/:  
this.nStartPos = nStart; {i09e1  
this.nEndPos = nEnd; R%\K<#^\  
nThreadID = id; ^< o"3?  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 z;#]xCV  
} y6C3u5`  
#'&&&_Hu3  
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public void run() 1U(P0$C  
{ 8+yCP_Y4  
while(nStartPos < nEndPos && !bStop) 1x8zub B  
{ "0ZBPp1q  
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try{ EFqYEDXW  
URL url = new URL(sURL); )W1tBi  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D`e6#1DbJ  
httpConnection.setRequestProperty("User-Agent","NetFox"); Svun RUE-f  
String sProperty = "bytes="+nStartPos+"-"; Ga M:/.  
httpConnection.setRequestProperty("RANGE",sProperty); Je1'0h9d  
Utility.log(sProperty); f%2>pQTq@)  
xh)
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InputStream input = httpConnection.getInputStream(); ,VdNP  
//logResponseHead(httpConnection); e[ 9  
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byte[] b = new byte[1024]; Pv#>j\OR&  
int nRead; (+w>hCI  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) h.%)RW?  
{ ^^FqN;  
nStartPos += fileAccessI.write(b,0,nRead); I"5VkeIx  
//if(nThreadID == 1) ZqK1|/\ rh  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {dF_=`.  
} p}:"@6
  

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Utility.log("Thread " + nThreadID + " is over!"); 3
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bDownOver = true; KdTDBC  
//nPos = fileAccessI.write (b,0,nRead); t<DZW#  
} (- QvlpZ  
catch(Exception e){e.printStackTrace ();} |h6u%t2AY  
} {
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} 8v V<A*`  
$(=0J*ND"  
}JlrWJRi  
//打印回应的头信息 L$ki>._i\  
public void logResponseHead(HttpURLConnection con) d09qZj>  
{ r;C BA'Z  
for(int i=1;;i++) W~i599!v  
{ |q+dTy_n  
String header=con.getHeaderFieldKey(i); |[B JZ  
if(header!=null) 8uD%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |iLf;8_:  
Utility.log(header+" : "+con.getHeaderField(header)); 7~2c"WE  
else E-?@9!2 &  
break; ~qu}<u)P  
} /ho7O/aAa  
} ;T,`m^@zf  
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6 #m:=  
public void splitterStop() ^2}p%j>  
{ 4Y `=`{Q  
bStop = true; WLkfo6Nw  
} `vc?*"  
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>= VCKN2'j  
} nSR<(-j!  
1 LUvs~Qu  
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/* mDX UF~G[  
**FileAccess.java *:tfz*FG$G  
*//文件访问(定位，写) tB/'3#o  
package NetFox; 2[QyH'"^E  
import java.io.*;
,JONc9  
3U
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public class FileAccessI implements Serializable{ {wwkbc*  
/)/>/4O  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 &(/QJ`*8  
RandomAccessFile oSavedFile; l`(pV ;{W  
long nPos; \F5d p  
8=Aoj%l#  
U%u%_{
-  
public FileAccessI() throws IOException Fsi;[be$A  
{ 3"HX':8x  
this("",0); \s^4f#  
} jk9/EmV*r  
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public FileAccessI(String sName,long nPos) throws IOException A=bBI>GEYP  
{ {O"N2W  
oSavedFile = new RandomAccessFile(sName,"rw"); oF {
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this.nPos = nPos; RQQ\y`h`  
oSavedFile.seek(nPos); hreG5g9{  
}  Ds@nuQ  
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public synchronized int write(byte[] b,int nStart,int nLen) gt|:K)[,6  
{ q
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int n = -1; RM6*c .  
try{ _sX@BE  
oSavedFile.write(b,nStart,nLen); 8L
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n = nLen; M%"{OHj!o  
} ^\3r}kJ0Lp  
catch(IOException e) Uf\,U8UB  
{ \@F~4,VT  
e.printStackTrace (); u81@vEK:_  
} rfHAz  
1|/-Ff"1@  
F|! ib5  
return n; F7lzc)
  
} 56 [+;*  
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} .X;DI<K  
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/* (y!V0iy]  
**SiteInfoBean.java L7OFZ|gUz  
*/ kS1?%E,)q  
package NetFox;
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>`o;hTS  
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public class SiteInfoBean { klxNGxWAX  
MR}h}JEx0  
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private String sSiteURL; //Site's URL cTu"T
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private String sFilePath; //Saved File's Path wNQhg  
private String sFileName; //Saved File's Name @D+2dT0[M  
private int nSplitter; //Count of Splited Downloading File ~tB#Q6`nB  
~d"9?K^#  
kmur={IR  
public SiteInfoBean() aM!%EaT  
{//nSplitter的缺省值为5 )m<CmYr2  
//default value of nSplitter is 5 =)IV^6~b  
this("","","",5); DtglPo_(  
} [/GCy0jk  
n?}7vz;  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)  @s7wKk  
{ Qa@] sWcM  
sSiteURL= sURL; m ^'!  
sFilePath = sPath; B*&HQW *u  
sFileName = sName; (Q[(]dfc  
this.nSplitter = nSpiltter; A?4s+A@Eg  
1;"DIsz@d  
zY2o;-d|4  
} _0h)O  
L.Tu7+M4  
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public String getSSiteURL() {N'<_%cu  
{ >eucQ]  
return sSiteURL; HJ0Rcw%  
} (Q F-=o  
#j4jZBOTM  
G^2%F5@  
public void setSSiteURL(String value) ^ RIWW0  
{ S:{`eDk\A_  
sSiteURL = value; kj/v$m  
} z#Db~  
|"i"8~/@<  
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public String getSFilePath() rq![a};~  
{ mIah[~G  
return sFilePath; c
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} -s&7zqW  
^k5#{?I  
fx*Q,}t  
public void setSFilePath(String value) O\q-Ai  
{ ,u^%[ejH  
sFilePath = value; @r3,|tkrz  
} y7U?nP ')+  
g[ O6WZ!F_  
 4
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public String getSFileName() \fSo9$  
{ tNC;CP#R+  
return sFileName; ^7iP!-w/  
} ES ?6  
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G0b##-.'^  
public void setSFileName(String value) ,iMdv+  
{ p@[n(?duC.  
sFileName = value; h)h%y)1  
} 4MPR
  
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public int getNSplitter() 6ac_AsFK  
{ {ug*  
return nSplitter; 3"LT''  
} "w{$d&+?ag  
D8\9nHUD`  
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public void setNSplitter(int nCount) ;YYnIb(  
{ sfzDE&>'  
nSplitter = nCount; 0`$fs.4c  
} L!0}&i;u~5  
} r;@"s g  
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/* iH>I
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**Utility.java =?[:Nj636  
*/ (CrP6]=  
package NetFox; ?yKG\tPhM  
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public class Utility { VYnB&3%DF  
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k|3hs('y|  
public Utility() cQrXrij;!  
{ l0=VE#rFl  
NfND@m{/  
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} [E)&dl_k  
[i8Ju  
//线程睡眠 0.0r?T  
public static void sleep(int nSecond) 6 jU?~  
{ <$Djags,F  
try{ w}0rDWuR[  
Thread.sleep(nSecond); @YbZ"Jb  
} 
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catch(Exception e) =}'7}0M_=  
{ N*SUA4bnuM  
e.printStackTrace (); D*t[5,~j  
} gdkHaLL"  
}
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p<c1$O*  
//日志 &"d :+!4h  
public static void log(String sMsg) vDC
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{ bKk7w#y  
System.err.println(sMsg); iz3Hoj  
} uLr-!T  
8\rAx P}=  
k,LaFe`W  
public static void log(int sMsg) 7ea%mg\  
{ &(h@]F!  
System.err.println(sMsg); 9F7}1cH7g@  
} XwDt8TxL  
} 8@r>`c  
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wU-Cb<^  
/* eN0lJ~  
**TestMethod.java ?;GXFKy  
*/
\-D[C+1(  
package NetFox; jJAr #|  
J|CCTXT  
3{M0iNc1  
public class TestMethod { .p%V]Ka  
O)c3Lm-w  
o.wXaS8  
public TestMethod() z`sW5K(A  
{ ///xx/weblogic60b2_win.exe wcW7k(+0  
try{ s){R/2O3F  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); q+ka}@  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); T;v^BVn  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Se|h]+G  
fileFetch.start(); &?# YjU"  
} #>2cfZ`6'J  
catch(Exception e){e.printStackTrace ();} JPpNCC.b  
\`W8#fob  
]L?WC  
} |Elz{i-  
^ #3,*(S  
M$e$%kPShE  
public static void main(String[] args) #M<u^$Jz  
{ |nY+Nen7  
new TestMethod(); j-v/;7s/B  
} Sg1,9[pb  
} m}t`43}QE  
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