http断点续传简单实现（java)

/* 
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**SiteFileFetch.java .Kz
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*/ |$.`4h?  
package NetFox; tFYod#  
import java.io.*; Kv>P+I'|r  
import java.net.*; v?qU/  
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public class SiteFileFetch extends Thread { `\#J&N  
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SiteInfoBean siteInfoBean = null; //文件信息Bean rIZ^ix-N  
long[] nStartPos; //开始位置 ).9m6.%Uk  
long[] nEndPos; //结束位置 ^|ln q.j  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4 .d~u@=  
long nFileLength; //文件长度 EnnE@BJ"  
boolean bFirst = true; //是否第一次取文件 u40<>A  
boolean bStop = false; //停止标志 f"g-Hbl5  
File tmpFile; //文件下载的临时信息 ?'r=>'6D  
DataOutputStream output; //输出到文件的输出流 |$a!Zx94^  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） d{G*1l(X  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1;N5@0%p  
{ E [b6k&A  
siteInfoBean = bean; 1|/]bffg!c  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); iF'qaqHWY4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !1cVg ls|  
if(tmpFile.exists ()) tg'2v/  
{ `78)|a*R.  
bFirst = false; U%E364;F  
read_nPos(); SK G!DKQ  
}  ]pP:  
else UKBaGX:v  
{ QO(P_az3mg  
nStartPos = new long[bean.getNSplitter()]; !f!HVna  
nEndPos = new long[bean.getNSplitter()]; >7I"_#x1:  
} A/w7(  
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} lzup! `g  
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public void run() af<wUxM0  
{ m6^n8%  
//获得文件长度 <maYS2  
//分割文件 TW5Pt{X=f  
//实例FileSplitterFetch N9=1<{Z  
//启动FileSplitterFetch线程 f?|cQ[#t!\  
//等待子线程返回 z*B-`i.  
try{ F>/"If#  
if(bFirst) b'$fr6"O1  
{ p`2w\P3;)  
nFileLength = getFileSize(); oVYW'~OID  
if(nFileLength == -1) S1D=' k]  
{ WXX)_L$2  
System.err.println("File Length is not known!"); y
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} U9eb&nd  
else if(nFileLength == -2) aokV'6  
{ &yN/AY
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System.err.println("File is not access!"); CFyu9Al  
} akB+4?+s)  
else yTwtGo&  
{ $Y9Wzv3Ra  
for(int i=0;i<nStartPos.length;i++) 
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{ ?'I pR  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); mcqLN5  
} r}Ec_0_lt  
for(int i=0;i<nEndPos.length-1;i++) S@[B?sNj  
{ 6 r}R%{  
nEndPos = nStartPos[i+1]; /<-@8CC<  
} @dx$&;w  
nEndPos[nEndPos.length-1] = nFileLength; C])b 3tM,7  
} m6 @,J?X  
} z6>Rv9f  
J.^%VnrFO9  
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//启动子线程 @^UnrKSd  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ipdGAG  
for(int i=0;i<nStartPos.length;i++) C|
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{ L92vb zP  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), k1HVvMD<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), dD.;P=AP  
nStartPos,nEndPos,i); "Q
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); FhVoN}  
fileSplitterFetch.start(); lbUUf}   
} nOj0"c  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;N;['xcx;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ('Doy1L  
nEndPos = " + nFileLength); nkii0YB!  
// fileSplitterFetch[nPos.length-1].start(); K! I]0!:  
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9~ JeI/  
//等待子线程结束 7ts`uI<E@7  
//int count = 0; oW\kJ>!  
//是否结束while循环 Kp)H>~cL  
boolean breakWhile = false; R-lpsvDDL2  
u
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vnOl-`Z ~  
while(!bStop) WO]9\"|y  
{ .&2Nm&y$K  
write_nPos(); .5K}R<  
Utility.sleep(500); ;r.0=Uo9]  
breakWhile = true; x}B_;&>&"_  
>3&Oe  
 L$Yg*]\  
for(int i=0;i<nStartPos.length;i++) CS|al(?~  
{ nXFPoR)T  
if(!fileSplitterFetch.bDownOver) (`me}8  
{ "B3&v%b  
breakWhile = false; \~~y1.,U.  
break; i}E&mv'  
} +fRABY5C  
} 3]cW08"c  
if(breakWhile) t
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break; vn5O8sD  
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//count++; wJ Qm7n-+  
//if(count>4) h5^qo ^;g7  
// siteStop(); FBGe s[,  
} o7=#ye&P  
aTU[H~dTU  
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System.err.println("文件下载结束！"); ` 5lW  
} uZhY)o*]@  
catch(Exception e){e.printStackTrace ();} cf`g.9pjlx  
} _ISaO C{2-  
B57MzIZi]  
#WqpU.
  
//获得文件长度 }eq*dr1`  
public long getFileSize() 'Tbdo >y  
{ 3[;fO_R  
int nFileLength = -1; ScCA8JgY  
try{ G%FLt[  
URL url = new URL(siteInfoBean.getSSiteURL()); S\"#E:A  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]21`x  
httpConnection.setRequestProperty("User-Agent","NetFox"); DqN<bu2  
" .<>(bE  
s=[T
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int responseCode=httpConnection.getResponseCode(); $LOwuvu>  
if(responseCode>=400) AJ"a  
{ unD.t  
processErrorCode(responseCode); Ygs:Ox"[-G  
return -2; //-2 represent access is error  up==g  
} d$qi.%<kh  
7
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String sHeader; "OWW -m  
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for(int i=1;;i++) VqL#w<A%  
{ "J"RH:$v  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); H9%[! RF  
//Utility.log(in.readLine()); Mfinh@K,  
sHeader=httpConnection.getHeaderFieldKey(i); l?<DY$H 0  
if(sHeader!=null) 'dvi@Jx  
{ _MLbJ  
if(sHeader.equals("Content-Length")) v9 *WM3  
{ ?R":"*eu  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )\RG NJMC  
break; M'|?*aNK  
} )j\9IdkU;y  
} W87kE?,  
else 4H*M^?h\#  
break; h-+vNhH  
} FaQz03N\  
} z0T9tN!(  
catch(IOException e){e.printStackTrace ();} >QSlH]M  
catch(Exception e){e.printStackTrace ();} >1  %|T  
7xh91EU:4  

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Utility.log(nFileLength); !%Bhg?  
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return nFileLength; 51gSbkVX  
} 8T5W6Zs1  

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//保存下载信息（文件指针位置） Pe/8=+qO  
private void write_nPos() K,5_{pj  
{ ^I:f4RWo  
try{ Dp-j(
F  
output = new DataOutputStream(new FileOutputStream(tmpFile)); q#PMQR"C  
output.writeInt(nStartPos.length); u9u'!hAGH  
for(int i=0;i<nStartPos.length;i++) j.kv!;Rj=  
{ nq qqP  
// output.writeLong(nPos); !S#K6:  
output.writeLong(fileSplitterFetch.nStartPos); L};P*{q2Z  
output.writeLong(fileSplitterFetch.nEndPos); 3g87ir  
} LZ}m;  
output.close(); p\22_m_wd  
} ;pt.)5  
catch(IOException e){e.printStackTrace ();} hV}C.- 6h  
catch(Exception e){e.printStackTrace ();} C8
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}  {HbSty  
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//读取保存的下载信息（文件指针位置） UK5u"@T  
private void read_nPos() k2/t~|5  
{ h{T{3  
try{ R5N~%Dg)3  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ^Eif~v  
int nCount = input.readInt(); dR!x)oO=  
nStartPos = new long[nCount]; SZD7"m4  
nEndPos = new long[nCount]; B|ctauJ  
for(int i=0;i<nStartPos.length;i++) vD76IG jm  
{ 3$4
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nStartPos = input.readLong(); 3w}ul~>
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nEndPos = input.readLong(); G * =>  
} w*\JA+  
input.close(); 2sYz$ZGC"#  
} &mkL4jXG  
catch(IOException e){e.printStackTrace ();} wGgeK,*_  
catch(Exception e){e.printStackTrace ();} a[jNT$8  
} z:oi@q  
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private void processErrorCode(int nErrorCode) <9
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{ [&pMU)   
System.err.println("Error Code : " + nErrorCode); 1EWskmp  
} #xh M&X  
cb }OjM F  
A [_T~+-G  
//停止文件下载 xg;vQKS6  
public void siteStop() ;sAe#b  
{ ?OFfU  4  
bStop = true; Y^b}~t  
for(int i=0;i<nStartPos.length;i++) |]eWO#vs  
fileSplitterFetch.splitterStop(); >{[  
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l p
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} qNWSDZQ  
} K0|:+s@u  
//负责部分文件的抓取 =klfCFwP  
**FileSplitterFetch.java :A+}fBIN  
*/ 7LsVlT[  
package NetFox; ]F3fO5Z  
VNwOD-b/]  
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z  
import java.io.*; hcoZ5!LvT  
import java.net.*; ?Kg_bvoR  
xAr&sGMA  
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public class FileSplitterFetch extends Thread { $!^C|,CS  
+5Ju `Z  
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String sURL; //File URL U6#9W}CE  
long nStartPos; //File Snippet Start Position %WPyc%I  
long nEndPos; //File Snippet End Position [Pl''[  
int nThreadID; //Thread's ID B & ]GGy  
boolean bDownOver = false; //Downing is over 5|Oj\L{  
boolean bStop = false; //Stop identical f^lhdZ\  
FileAccessI fileAccessI = null; //File Access interface q+ `QiPj  
N%9?8X[5  
#
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException {a
]u  
{ EUW>8kw0  
this.sURL = sURL; ~-UO^$M-  
this.nStartPos = nStart; wli H3vA_  
this.nEndPos = nEnd; /4;Sxx-  
nThreadID = id; G +AP."M?  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 4m6/ba  
} 6!H,(Z]j  
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\f7R^;`_<R  
public void run() K{:[0oIHc  
{ x,HD,VQR/  
while(nStartPos < nEndPos && !bStop) 55/)2B2J  
{  r}}2Kl  
!6hV|2aJy  
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try{ K^P&3H*(/n  
URL url = new URL(sURL); :i|Bz6Ht4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <fHN^O0TS  
httpConnection.setRequestProperty("User-Agent","NetFox"); Rm`P.;%  
String sProperty = "bytes="+nStartPos+"-"; F`1J&S;C  
httpConnection.setRequestProperty("RANGE",sProperty); 39L_O RMH  
Utility.log(sProperty);
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InputStream input = httpConnection.getInputStream(); 7rG+)kHG  
//logResponseHead(httpConnection); iUs_)1  
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byte[] b = new byte[1024]; R ^ZOcONd-  
int nRead; mY]o_\`  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) cPkP/3I]h  
{ S VypR LVB  
nStartPos += fileAccessI.write(b,0,nRead); G8'  
//if(nThreadID == 1) ab`9MJc;  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5!aI~(3<  
}  FL b  
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Utility.log("Thread " + nThreadID + " is over!"); 0`
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bDownOver = true; =Y*@8=V  
//nPos = fileAccessI.write (b,0,nRead); "{Hl! Zq/  
} pu_?)U  
catch(Exception e){e.printStackTrace ();} ]x(6^:D5  
} Dl,sl>{  
} NKTy!zWh  
w`v`aw]  
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//打印回应的头信息 V+r&Z<&  
public void logResponseHead(HttpURLConnection con) |T]&8Q)S  
{ y`z4S,  
for(int i=1;;i++) ,L4zhhl!_  
{ Yhjv[9  
String header=con.getHeaderFieldKey(i); wd3OuDrU  
if(header!=null)  FjMKb  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ti7 @{7>  
Utility.log(header+" : "+con.getHeaderField(header)); PPh<9$1\g  
else =RZPDu  
break; |oSqy  
} gyegdky3  
} ryqu2>(   
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public void splitterStop() h50]%tp\  
{ x U"g~hT  
bStop = true; Pz\ByD  
} 4iZg2"[D  
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} I8c:U2D  
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/* Ikw.L  
**FileAccess.java d[ _@l  
*//文件访问(定位，写) 0gHV(L?  
package NetFox; 'z{
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import java.io.*; w#ZzmO  
sLFZ61rT  
j-VwY/X  
public class FileAccessI implements Serializable{ UZ "!lpg  
sbhzER  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 [rW];H8:~  
RandomAccessFile oSavedFile; x-W~&`UU  
long nPos; EhW"s%Q  
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d
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public FileAccessI() throws IOException Zz+v3
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{ U| ?68B3  
this("",0); mU"Am0Bdjq  
} <P
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public FileAccessI(String sName,long nPos) throws IOException X|G[Ma?   
{ E" >`  
oSavedFile = new RandomAccessFile(sName,"rw"); oE6`]^^  
this.nPos = nPos; 7WY~v2SDF  
oSavedFile.seek(nPos); 1Kr$JIcd  
} z30 mk  
DuT6Od/f  
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public synchronized int write(byte[] b,int nStart,int nLen) ?k($Tc&Q  
{ =F}qT|K  
int n = -1; sI h5cT  
try{ Ul6|LTY  
oSavedFile.write(b,nStart,nLen); [zXC\)&!  
n = nLen; q2'}S A/  
} !^s -~`'\~  
catch(IOException e) cP\z*\dS  
{ !Q5,Zhgr  
e.printStackTrace (); 
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} U@
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ob'" ^LO\  
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return n; TU58  
} WRwx[[e6z  
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} +\;Ro18?  
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{QaO\{J=  
/* 4; 0#Z^p  
**SiteInfoBean.java !]E]Xd<  
*/ $ZZ?*I  
package NetFox; )?7/fF)@|  
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public class SiteInfoBean { WPAUY<6f  
;\6@s3  
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private String sSiteURL; //Site's URL mEu2@3^E }  
private String sFilePath; //Saved File's Path N
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private String sFileName; //Saved File's Name ULBEe@s  
private int nSplitter; //Count of Splited Downloading File jT< I`K*  
|=0w_)Fa]  
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public SiteInfoBean() x DNu'  
{//nSplitter的缺省值为5 j@^zK!mO  
//default value of nSplitter is 5 c q[nqjC=  
this("","","",5); $Dx*[.M3>  
} zi_$roq=)  
ARt{ 2|  
!8T04988j  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) B|yz~wuS  
{ _+nk3-yQw  
sSiteURL= sURL; Tx
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sFilePath = sPath; w{|`F>f9  
sFileName = sName; *s-s1v  
this.nSplitter = nSpiltter; UN
F\k1[  
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U<Qi`uoj!  
} +N7<[hE;  
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public String getSSiteURL() u\= 05N6G  
{ Otx>S' 5  
return sSiteURL; <[-{:dH,5  
} I)vR  
Z 4i5,f  
5Phsh  
public void setSSiteURL(String value) =Ul"{T<  
{  S.B?l_d^  
sSiteURL = value; ::'Y07  
} 7l/lY-zO  
0Z]HH+Z;  
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public String getSFilePath() C
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{  s!
  
return sFilePath; &A.0(s  
} wB'!@>db  
wIR"!C>LE  
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public void setSFilePath(String value) !iNwJ|0  
{ ]!P8{xmb@  
sFilePath = value; On~KTt3Mp  
} WcS`T?Xa  
)8rF'pxI  
o _l_Yi  
public String getSFileName() 3 yb]d5:U  
{ M%Rr=  
return sFileName; ]+m2pEO  
} U1Fo #L  
>i  >|]  
8#tuB8>  
public void setSFileName(String value) _yR_u+
5  
{ )g^qgxnnV  
sFileName = value; oqysfLJ  
} q+oc^FD?@  
8!!h6dQgI  
)*XWe|H_  
public int getNSplitter() ?PTXgIC  
{ ILl~f\xG)  
return nSplitter; !l0"nPM=  
} nK+ke)'Zv=  
,ayJgAD  
2gkN
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public void setNSplitter(int nCount) r-!Qw1  
{ \,X)!%6kZ  
nSplitter = nCount; !9YCuHj!p  
} $ (xdF  
} 1n&%L8]  
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/3^XJb$Sa  
/* iymN|KdpaZ  
**Utility.java :aaX Y:<  
*/ |4 \2,M
#  
package NetFox; 4r~K`)/S'  
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public class Utility { ^VG].6  
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|39,n~"o&  
public Utility() -P|claO0  
{ W^xO/xu1/  
[xrsa!$   
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} [ 't.x=  
yhbU;qEG9  
//线程睡眠 Jq(;BJ90R  
public static void sleep(int nSecond) 5Rs#{9YE  
{ Z
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try{ $57Q g1v  
Thread.sleep(nSecond); -ZSN0Xk  
} N6u>V~i  
catch(Exception e) S2Ez}*plp  
{ ,.V<
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e.printStackTrace (); ]dJ"_  
} ~&RrlFh  
} ?<W|Ya  
!vJ$$o6#  
//日志 rb4;@
&  
public static void log(String sMsg) `o }+2Cb  
{ PM
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System.err.println(sMsg); oOvQAW8`  
} un~`|  
u*I'c2m  
Q8h0.(#-  
public static void log(int sMsg) =. \hCgq  
{ %dW;P[0  
System.err.println(sMsg); uQx/o^  
} B|"i`{>  
} ! M CV@5$  
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/* 4TPdq&';C:  
**TestMethod.java Op]*wwI*h  
*/ n~\; +U  
package NetFox; FNF`Z  
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wf]?:'}  
public class TestMethod { ]4[%Sv6]G  
2#^g] o-N  
`JiWS
 
public TestMethod() Q Kr/  
{ ///xx/weblogic60b2_win.exe ^JMG'@x  
try{ |,oLZCNa  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); T!y 9v5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); yn]Sc<uK  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Lhux~,EH  
fileFetch.start(); pKq[F*Lut  
} 4XER7c  
catch(Exception e){e.printStackTrace ();} 1?|"33\03R  
u=v-,Tw  
>FOCdlJ#  
} Ot\[Ya''  
i?(cp["7  
Q"{Dijc%  
public static void main(String[] args) .(cpYKFX  
{ &}P#<"Fo8Q  
new TestMethod(); vw3[(_MV3_  
} PpG;5  
} uyk;]EYjHZ  
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