http断点续传简单实现（java)

/* 5$L=l  
**SiteFileFetch.java 8iwqy0<  
*/ tJ!s/|u(  
package NetFox; NU$?BiB?R  
import java.io.*; 8^6
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import java.net.*; ^K n{L  
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public class SiteFileFetch extends Thread { ![4<6/2gy  
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SiteInfoBean siteInfoBean = null; //文件信息Bean \-~TW4dYe  
long[] nStartPos; //开始位置 eNw9"X}g  
long[] nEndPos; //结束位置 @XFy^?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 r__Y{&IO  
long nFileLength; //文件长度 =dTsGNz  
boolean bFirst = true; //是否第一次取文件 %vFoTu)2  
boolean bStop = false; //停止标志 i$!-mYi+Q!  
File tmpFile; //文件下载的临时信息 Kn+m9  
DataOutputStream output; //输出到文件的输出流 J
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） {P@OV1  
public SiteFileFetch(SiteInfoBean bean) throws IOException COk;z.Kn  
{ 1Ydym2  
siteInfoBean = bean; 6`Af2Y_  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [<p7'n3x  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); DKxzk~sOM  
if(tmpFile.exists ()) XKt">W  
{ ts3BmfR?  
bFirst = false; Km9Y_`?  
read_nPos(); W_ hckq.  
} #^~[\8v>  
else N++jI(  
{ (:2,Rr1"  
nStartPos = new long[bean.getNSplitter()]; `cBV+00YS  
nEndPos = new long[bean.getNSplitter()]; m?Qr)F_M
 
} J}UG{RttI  
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} o:irwfArv  
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public void run() 7$&3(#!N  
{ }^np  
//获得文件长度 UBy< vwnU  
//分割文件 PtT=HvP!k  
//实例FileSplitterFetch W{!GL  
//启动FileSplitterFetch线程 Eax^1 |6  
//等待子线程返回 ni$S@0  
try{ _H+|Ic  
if(bFirst) $<(FZb=  
{ CZL:&~l1  
nFileLength = getFileSize(); ;>duY\$<  
if(nFileLength == -1) !$i*u-%4  
{ &58+-jzW  
System.err.println("File Length is not known!"); !K~:crUV|S  
} tuF hPqe {  
else if(nFileLength == -2) %@jL?u  
{ `Z:5E  
System.err.println("File is not access!"); <cn{S`  
} b=Y:`&o=[  
else ~:\QC  
{ dE[nPtstb  
for(int i=0;i<nStartPos.length;i++) &eHhj9  
{ W%xg;uzp  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); I*Q^$YnM  
} N5%zbfKM  
for(int i=0;i<nEndPos.length-1;i++) 9j;L-  
{ ~
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nEndPos = nStartPos[i+1]; SXW8p>1Jw  
} <[eE5X(  
nEndPos[nEndPos.length-1] = nFileLength; oS/cS)N20  
} N=QeeAI}}m  
} l12_&o"C~  
9$u'2TV  
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//启动子线程 z"@yE*6  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 9svnB@  
for(int i=0;i<nStartPos.length;i++) y.l`NTT]<  
{ "#a_--"k9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1b,,uI_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ?{OB+f}Mo  
nStartPos,nEndPos,i); A@kp`-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u
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fileSplitterFetch.start(); "XEKoeG{  
} 1UHStR  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 61W ms@D%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); < c}cgD4  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", v&NC` dVR  
nEndPos = " + nFileLength); PsLMV:O9S  
// fileSplitterFetch[nPos.length-1].start(); v;q<h  
8Q%rBl.  
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//等待子线程结束 ;;9W/m~]  
//int count = 0; >Bj+!)96q  
//是否结束while循环 %ifq4'?Z   
boolean breakWhile = false; '<A:`V9M}v  
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while(!bStop) py9HUyr5eZ  
{ 'ow`ej  
write_nPos(); B4yC"55  
Utility.sleep(500); /~49.}yt  
breakWhile = true; me+F0:L  
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for(int i=0;i<nStartPos.length;i++) @o[C Xrz  
{ /a?*Ap5"  
if(!fileSplitterFetch.bDownOver) l 4zl|6%  
{ \m3;<A/3n  
breakWhile = false; L@"1d.k_  
break; 0<8pG:BQ  
} +$hqwNh@Z@  
} 5w\>Whbd  
if(breakWhile) ;<JyA3i^V,  
break; nty^De%  
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//count++; =,/08Cs  
//if(count>4) D{]t50a.  
// siteStop(); &vf%E@<  
} +wAH?q8f  
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System.err.println("文件下载结束！"); WW'8&:x  
} k}5Sz  
catch(Exception e){e.printStackTrace ();} 5ayM}u%\~  
} ^r u1QDT  
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//获得文件长度 MT8BP)C  
public long getFileSize() x-Kq=LFy.  
{ [Ch)6p  
int nFileLength = -1; ^ di[J^  
try{ ;\F3~rl  
URL url = new URL(siteInfoBean.getSSiteURL()); CnJrJ>l  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t8Sblgq  
httpConnection.setRequestProperty("User-Agent","NetFox"); DriJn`vtzq  
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int responseCode=httpConnection.getResponseCode(); 3HU_~%l  
if(responseCode>=400) vPm&0,R*y:  
{ c~@Z  
processErrorCode(responseCode); s~@4  
return -2; //-2 represent access is error ~w&P]L\dB  
} 7IrbwAGZ3  
}=1#ANM1  
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String sHeader; qno8qF*  
#}/YnVk  
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for(int i=1;;i++) x
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{ "ooq1 0P  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ionFP
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//Utility.log(in.readLine()); Sn I-dXNF  
sHeader=httpConnection.getHeaderFieldKey(i); 1@&i ju5  
if(sHeader!=null) ?onaJ=mT  
{ 8X6F6RK6,1  
if(sHeader.equals("Content-Length")) xz-z" 8d  
{ uQwKnD?F+e  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Xknp*(9  
break; MZyzc{c,  
} ,t`u3yk
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} 5'JONw'\  
else Qi 3di  
break; or?@Ti;  
} Vv"JN?dHi  
} f^P:eBgpx  
catch(IOException e){e.printStackTrace ();} Uxla,CCp-  
catch(Exception e){e.printStackTrace ();} ~ .}  
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Utility.log(nFileLength); y4%u</  
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return nFileLength; -^C't_Q o  
} pzX684  
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k 8C[fRev  
//保存下载信息（文件指针位置） O5:?nD  
private void write_nPos() 5pJ)OX  
{ n"[VM=YGI  
try{ ra="4T$va  
output = new DataOutputStream(new FileOutputStream(tmpFile)); DB1GW,  
output.writeInt(nStartPos.length); 0q|.]:][Eo  
for(int i=0;i<nStartPos.length;i++) fOE8{O^W  
{ So&an !  
// output.writeLong(nPos); zh5$$*\  
output.writeLong(fileSplitterFetch.nStartPos); ]g#ur@Y%  
output.writeLong(fileSplitterFetch.nEndPos); |'w_5?|4  
} K4]42#
  
output.close(); Rgb1B3gu  
} PNm WZW*  
catch(IOException e){e.printStackTrace ();} >EVlMt27'  
catch(Exception e){e.printStackTrace ();} H3$~S '  
} "A_,Ga  
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\E9Hk{V:6  
//读取保存的下载信息（文件指针位置） +Dg%ec  
private void read_nPos() XCQS_'D  
{  U>0' K3_  
try{ 80PlbUBb!  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9.<dS  
int nCount = input.readInt(); c$X0C&m  
nStartPos = new long[nCount]; yZ {H  
nEndPos = new long[nCount]; Ee&A5~  
for(int i=0;i<nStartPos.length;i++) / v";u)  
{ ls5s
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nStartPos = input.readLong(); L0v& m  
nEndPos = input.readLong(); \,:3bY_d  
} ^%)H;  
input.close(); JfJUOaL  
} L@ ,-V  
catch(IOException e){e.printStackTrace ();} fZoV\a6Kj  
catch(Exception e){e.printStackTrace ();}
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} 
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private void processErrorCode(int nErrorCode) t;[L-|^  
{ d2b L_  
System.err.println("Error Code : " + nErrorCode); +UzFHiGy#  
} PQla-  
Mx?{[zT"  
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//停止文件下载 O>zPWVwa  
public void siteStop() F
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{ #+mt}w/  
bStop = true; w28!Yj1Q  
for(int i=0;i<nStartPos.length;i++) NGl/F{<  
fileSplitterFetch.splitterStop(); ,2Y PD4  
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+!  

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} %bM^/7  
} rlj @'  
//负责部分文件的抓取 ;]ojfR=?%  
**FileSplitterFetch.java ]B;GU  
*/ r 5!ie!5gE  
package NetFox; (TufvHC  
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import java.io.*; 4::>C
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import java.net.*; @Y/PvS8!  
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public class FileSplitterFetch extends Thread { U.7;:W}c  
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String sURL; //File URL /*5t@_0fe  
long nStartPos; //File Snippet Start Position t;P%&:"@M  
long nEndPos; //File Snippet End Position DNsDE
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int nThreadID; //Thread's ID ]~my<3j}or  
boolean bDownOver = false; //Downing is over gu+c7qe  
boolean bStop = false; //Stop identical =NyN.^bwT  
FileAccessI fileAccessI = null; //File Access interface uzf@49m]m  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _pu G?p  
{ L2s)B  
this.sURL = sURL; }}a<!L,{  
this.nStartPos = nStart; <8UqV.&  
this.nEndPos = nEnd; VGbuEC[Y  
nThreadID = id; _Je k;N  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;p~&G"-C`  
} eySV -f{  
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#"}Z'|X*  
public void run() s: c  
{ yZf+*j/a7  
while(nStartPos < nEndPos && !bStop) s>Eu[uA  
{ M8Y\1
#~  
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try{ b6Jv|1w'  
URL url = new URL(sURL); #u8|cs!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 
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httpConnection.setRequestProperty("User-Agent","NetFox"); #JAU5d  
String sProperty = "bytes="+nStartPos+"-"; (bfHxk
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httpConnection.setRequestProperty("RANGE",sProperty); D#>+]}5@x  
Utility.log(sProperty); pdnkHR$  
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InputStream input = httpConnection.getInputStream(); 3c5=>'^F  
//logResponseHead(httpConnection); ZyE2=w7n  
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byte[] b = new byte[1024]; wH&Rjn  
int nRead; _vA\j  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) '</  
{ &I8,<(`  
nStartPos += fileAccessI.write(b,0,nRead); ,|?-\?I  
//if(nThreadID == 1) 5.J$0wK'6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }8E//$J  
} ?}*A/-Hx0U  
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Utility.log("Thread " + nThreadID + " is over!"); VFN\ Ryd  
bDownOver = true; `r"euO r\  
//nPos = fileAccessI.write (b,0,nRead); @
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} uHdrHP  
catch(Exception e){e.printStackTrace ();} 4;;F(yk8  
} ybBLBJb  
} XcJ'w  
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?9qA"5  
//打印回应的头信息 J~z;sTR  
public void logResponseHead(HttpURLConnection con) EUdu"'=4a  
{ 7+aTrE{  
for(int i=1;;i++) "rz|sbj  
{ y}jX/Ln  
String header=con.getHeaderFieldKey(i); Ba/Z<1)  
if(header!=null) H2
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); zuOx@T^  
Utility.log(header+" : "+con.getHeaderField(header)); ?'H);ou-p  
else 41%B%K*  
break; ^n5[pF}Gw  
} M70Xdn  
} ;$W/le"Xr  
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x  
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public void splitterStop() fRo_rj _  
{ T:Dp+m!\{  
bStop = true; ]saf<?fzr  
} mLM$dk3  
7*5$=z4,1  
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} 620y[iiK$  
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)%8oE3O#  
/* VXvr`U\  
**FileAccess.java c }>:>^  
*//文件访问(定位，写)  N7j  
package NetFox; VHX&#vm*  
import java.io.*; gP.Q_/V  
T{M~*5$  
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public class FileAccessI implements Serializable{ v%3mhk#  
r@+IDW.=9  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @L|X('i  
RandomAccessFile oSavedFile; ,)A^3Q*  
long nPos; jh.W$.Oq  
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public FileAccessI() throws IOException "H>L!v  
{ ;J pdnV  
this("",0); q4vu r>m6  
} 10dVV[=  
+F ~;Q$T  
.:,RoK1  
public FileAccessI(String sName,long nPos) throws IOException lpkg(J#&  
{ 0j%@P[zQ  
oSavedFile = new RandomAccessFile(sName,"rw"); dwks"5l  
this.nPos = nPos; LH..8nfl  
oSavedFile.seek(nPos); e47JLW&b  
} le`&VdE^  
((rk)Q+;v  
/=4P<&J  
public synchronized int write(byte[] b,int nStart,int nLen) +v%V1lf^~  
{ z^9Yoqog  
int n = -1; MJ[#Gq\0R  
try{ th8f  
oSavedFile.write(b,nStart,nLen); P%>? O :a  
n = nLen; 4R\bU"+jZ_  
} y|b|_eE?{  
catch(IOException e) B+|E|8"  
{ p8y_uNQE  
e.printStackTrace (); /zn|?Y[  
} PPT"?lt*&  
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return n; !o &+  
} k%#`{#ni  
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} m` cw:  
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9Qp39(l:  
/* O z%K*  
**SiteInfoBean.java .z+?b8Q\  
*/ 1&c>v3 $2  
package NetFox; zLXmjrC  
%JDG aG'  
CFqoD l  
public class SiteInfoBean { -yeQQ4b  
0m,A`*o  
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private String sSiteURL; //Site's URL *Id$%O  
private String sFilePath; //Saved File's Path "s2?cQv{#  
private String sFileName; //Saved File's Name i^sK+v  
private int nSplitter; //Count of Splited Downloading File zvL&V .>  
~\/>b}^uf'  
0CI?[R\  
public SiteInfoBean() I})la!9  
{//nSplitter的缺省值为5 ?HVsIAU  
//default value of nSplitter is 5 ]CH@T9d5V  
this("","","",5); v vlfL*f  
} {6)fZpd)@  
?ECmPS1  
RH ow%2D  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 3tI=?E#  
{ 8rXq-V_u  
sSiteURL= sURL; &/R@cS6}'  
sFilePath = sPath; C.s{&  
sFileName = sName; @/yRE^c  
this.nSplitter = nSpiltter; lDV8<  
g^8dDY[%  
%([$v6y  
} OYC4iI  
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public String getSSiteURL() cO<]%L0  
{ 57Ir
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return sSiteURL; \v]}  
} wRb%-s  
y&9S+  
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public void setSSiteURL(String value) zc]
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{
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sSiteURL = value; QL}5vSl  
} R B.j@*  
u#%Ig3  
|8&AsQd  
public String getSFilePath() O;f^'N  
{ 4C[,S|J  
return sFilePath; fOJk+? c  
} Rp A76ug  
Nv*x^y]  
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public void setSFilePath(String value) qLKyr@
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{ u_@%}zo?5*  
sFilePath = value; yk#yrxM
 
} jd l1Q<Z  
n<8$_?-
 
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public String getSFileName() H#k"[eZ  
{ Ol9U^  
return sFileName; f1=BBQY >  
} x`PIJE  
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v6oPAqj,r  
public void setSFileName(String value) CB_(9T72H  
{ :tdx:  
sFileName = value; VbM5]UT/  
} /}2 bsiJT  
0NfO|l7P  
)]J I Q"rR  
public int getNSplitter() 5h1!E  
{ Y:^ =jV7  
return nSplitter; !W^2?pqN  
} _4o2AS:j  
aen(Mcd3bg  
nX5*pTfjL3  
public void setNSplitter(int nCount) @5 kKMz  
{ Yp 6;Y7^  
nSplitter = nCount; :m5& i&  
} )oTEB#J  
} Qat%<;P2  
FvG9PPd  
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/* z:u`W#Rf  
**Utility.java $2]1 3j  
*/ MGc=TQ.  
package NetFox; @EfCNOy  
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z(.$>O&6H  
public class Utility { L)8+/+  
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@EO#Ms  
public Utility() 1a_;[.s  
{ 7b+
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H!F'I)1  
{N)\It  
} :1_hQeq  
=e$ #m;  
//线程睡眠 zIF &ZYP  
public static void sleep(int nSecond) [w=x0J&  
{ bQXxb(^  
try{ 6$ IXER  
Thread.sleep(nSecond); C$*`c6R  
} [7<X&Q  
catch(Exception e) zmr=iK  
{ ^+`vh0TPQ  
e.printStackTrace (); t)cG_+rJ  
} G]P4[#5  
} :U)e 8  
bcM#KA  
//日志 32~Tf,  
public static void log(String sMsg) e"r}I!.  
{ /lr RbZ  
System.err.println(sMsg); KG>.7xVWV7  
} !Q.c8GRUQ  
Z6D4VZVF  

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public static void log(int sMsg) FT|*~_@  
{ iM8hGQ`  
System.err.println(sMsg); zNE!m:s  
} /4_}wi\  
} *N>Qj-KAM_  
=7e8N&-nv  
^]U2Jd  
/* !-N!80  
**TestMethod.java iS=T/<|?  
*/ 30DpIkf  
package NetFox; /;OJ=x3i  
N"r ;d+LTL  
'/sc `(`:0  
public class TestMethod { m9L+|r  
H~ks"D1  
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public TestMethod() l$zNsf.  
{ ///xx/weblogic60b2_win.exe ,1~Zqprn  
try{ //J:p,AF  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ]G1j\wnF  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); uFok'3!g7%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @J
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fileFetch.start(); DVB:8"Bu  
} (S2<6Nm8  
catch(Exception e){e.printStackTrace ();} kk~{2  
Lvp/} /H/  
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} OW-+23)sj  
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public static void main(String[] args) 5Q%#Z L/'  
{ Y\op9Fw  
new TestMethod(); E_H1X'|qS4  
} qL'3MY.!  
} ?0?'  
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