http断点续传简单实现（java)

/* 8`Q8Mct$<  
**SiteFileFetch.java oJK1~;:  
*/ y-m<&{q  
package NetFox; c}kZx1  
import java.io.*; 'e_^s+l)a  
import java.net.*; fWhwI+  
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public class SiteFileFetch extends Thread { A6v02WG_1T  
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SiteInfoBean siteInfoBean = null; //文件信息Bean *kY\,r&!P  
long[] nStartPos; //开始位置 W(Z_ac^e[  
long[] nEndPos; //结束位置 RMUR@o5N  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 bq/m?;  
long nFileLength; //文件长度 TCYjj:/  
boolean bFirst = true; //是否第一次取文件 |6'(yn  
boolean bStop = false; //停止标志 X1?7}VO  
File tmpFile; //文件下载的临时信息 ZgQ4~s  
DataOutputStream output; //输出到文件的输出流 qqA(Swe)T  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） j9)P3=s  
public SiteFileFetch(SiteInfoBean bean) throws IOException q4'szDYO2  
{ fDt#<f 4;  
siteInfoBean = bean; }R4%%)j(Vj  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); CG*eo!Nw  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); nd*9vxM  
if(tmpFile.exists ()) c ]M!4.  
{ Aw9se"d  
bFirst = false; <aR9,:  
read_nPos(); JwG$lGNJ  
} T;K@3]FbX  
else @[h)M3DFd  
{ GEj/Z};;[b  
nStartPos = new long[bean.getNSplitter()]; 1;?n]L`T  
nEndPos = new long[bean.getNSplitter()]; iU"jV*P]  
} Aq674  
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} 11t+ a,fM  
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public void run() Xg
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{ "#1KO1@G  
//获得文件长度 2f
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//分割文件 2yZ/'}Mw  
//实例FileSplitterFetch ,l/~epx4v)  
//启动FileSplitterFetch线程 \) DJo  
//等待子线程返回 .<&o,D  
try{ g(Q
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if(bFirst) Lt`d {s  
{ `/?XvF\  
nFileLength = getFileSize(); /$ Gp<.z  
if(nFileLength == -1) Bh3N6j+$d  
{ &/QdG= r+  
System.err.println("File Length is not known!"); ,dn6z#pb+  
} >%Rb}Ki4  
else if(nFileLength == -2) kS_oj  
{ p1~u5BE7O  
System.err.println("File is not access!"); KFQ4vavNh  
} v:/+OzY  
else LpRl!\FY$  
{ 1eQfc{[g  
for(int i=0;i<nStartPos.length;i++) CB
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{ Mn$w_Z?  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1^&
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} 8 KDF*%7'  
for(int i=0;i<nEndPos.length-1;i++) eh4`a
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{ Cka
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nEndPos = nStartPos[i+1]; Jv_KZDOdk  
} NQBa+N  
nEndPos[nEndPos.length-1] = nFileLength; q8&2
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} > mI1wV[  
} X}"Ic@8  
":=\ci]e%  
4}0DEH.Vx  
//启动子线程 z}Y23W&sX  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 9Q\CJ9  
for(int i=0;i<nStartPos.length;i++) h
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{ w=e_@^Fkx  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [/Q .MmnL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), RWyDX_z#<  
nStartPos,nEndPos,i); </xz V<Pi  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); etnq{tE5  
fileSplitterFetch.start(); M1nH!A~o  
} 9Yu63s ia  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9)c{L<o}T  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); WY>r9+A?W  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", *[VO03  
nEndPos = " + nFileLength); n8h1SlK08  
// fileSplitterFetch[nPos.length-1].start(); C8^h`B9z&I  
kHWW\?O  
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//等待子线程结束 PhUG}94  
//int count = 0; ojmF:hR"  
//是否结束while循环 6YErF|  
boolean breakWhile = false; hk5[ N=  
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while(!bStop) bQ%6z}r  
{
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write_nPos(); "+0Yhr?  
Utility.sleep(500); Gy;>.:n  
breakWhile = true; #'5C*RO  
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for(int i=0;i<nStartPos.length;i++) d#tqa`@~  
{ ,(&p"O":  
if(!fileSplitterFetch.bDownOver) |_6V+/?"?`  
{ UO1WtQyu,H  
breakWhile = false; 9#;GG3  
break; sn!E$ls3O  
} %#_"Ie  
} y 4 wV]1  
if(breakWhile) lRk
)  
break; "_
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//count++; _YK66cS3E/  
//if(count>4) X[SdDYMY  
// siteStop(); $q$G  
} @sr~&YhA  
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ia9=&Hy])  
System.err.println("文件下载结束！"); 7^oO N+=d  
} h&|S*  
catch(Exception e){e.printStackTrace ();} DXa!"ZU
 
} o){\qhLp  
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4\_~B{kzZ  
//获得文件长度 B
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public long getFileSize() hEh` cBO  
{ _'*Vcu`Y  
int nFileLength = -1; o*t4zF&n  
try{ L-9AJk>V  
URL url = new URL(siteInfoBean.getSSiteURL()); S
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  5(\H:g\z  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5r` x\  
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int responseCode=httpConnection.getResponseCode(); &}rmDx  
if(responseCode>=400) %TeH#%[g>\  
{ %Q080Ltet  
processErrorCode(responseCode); t?(fDWd|-  
return -2; //-2 represent access is error yno X=#`  
} *'n L[]  
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String sHeader; 4c]=kbGW  
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for(int i=1;;i++) _u9bZ'  
{ 
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());  X@Bg_9\i  
//Utility.log(in.readLine()); )tv~N7  
sHeader=httpConnection.getHeaderFieldKey(i); ^4~?]5Y\  
if(sHeader!=null) 7NMy1'-q  
{ 6W/uoH=;  
if(sHeader.equals("Content-Length")) MAcjWb~f  
{ 4g)$(5jI}  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); emMk*l,  
break; _)Ad%LPsd7  
} )E*-  
} 2@Zw#2|
]  
else ;3\'}2^|l  
break; hiEosI C  
} T`2a)  
} Rjn%<R2nW  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} b=kY9!GN,v  
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Utility.log(nFileLength); |,T"_R_K  
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return nFileLength; -HvJ&O.V$  
} JYnyo$m/  
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//保存下载信息（文件指针位置） a5/r|BiBK  
private void write_nPos() i(YR-vYK  
{ g:YUuZ  
try{ sWKv>bx  
output = new DataOutputStream(new FileOutputStream(tmpFile));  ;!j/t3#a  
output.writeInt(nStartPos.length); I9h{fB  
for(int i=0;i<nStartPos.length;i++) rX22%~1  
{ "iJAM`Hi  
// output.writeLong(nPos); L>pSE'}  
output.writeLong(fileSplitterFetch.nStartPos); AZ SaI  
output.writeLong(fileSplitterFetch.nEndPos); k- exqM2x=  
} l-2lb&n  
output.close(); f\z9?Z(~  
} _6->D[dB  
catch(IOException e){e.printStackTrace ();} X=? \A{Y  
catch(Exception e){e.printStackTrace ();} _ucixM#  
} ; hU9_e  
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//读取保存的下载信息（文件指针位置） _8 l=65GW  
private void read_nPos() ?4t~z 1.f  
{ = gcZRoL  
try{ GuF-HP}xM  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ]''tuo2g8  
int nCount = input.readInt(); t&-c?&FO\;  
nStartPos = new long[nCount]; qnzNJ_ `R  
nEndPos = new long[nCount]; ie/QSte  
for(int i=0;i<nStartPos.length;i++) I#xhmsF  
{ a?)g>e HN  
nStartPos = input.readLong(); n65fT+;  
nEndPos = input.readLong(); .:/X~{  
} UJ`%uLR~  
input.close(); @^`5;JiUk  
} xzRC %  
catch(IOException e){e.printStackTrace ();} \\/ !I   
catch(Exception e){e.printStackTrace ();} w_YY~Af  
} w$749jGx  
s%
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9  
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private void processErrorCode(int nErrorCode) 7A  
{ ">s0B5F7  
System.err.println("Error Code : " + nErrorCode); Q8
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} G+iJS!=  
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vf`]  
//停止文件下载 R xWD>:  
public void siteStop() ;e~K<vMm;y  
{ *gI9CVfQl  
bStop = true; -Q!?=JNtQ  
for(int i=0;i<nStartPos.length;i++) *JaFt@ x  
fileSplitterFetch.splitterStop(); _xdttO^N  
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 *8 ]  
} 1xwq:vFC.  
} W*D*\E  
//负责部分文件的抓取 <zu)=W'R]  
**FileSplitterFetch.java ,0$b8lb;x/  
*/ r3.v^  
package NetFox; 1z[blNs&  
fVBRP[,  
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import java.io.*; S[uHPYhlA  
import java.net.*; &S#bLE  
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public class FileSplitterFetch extends Thread { WTh|7&  
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String sURL; //File URL lc0ZfC  
long nStartPos; //File Snippet Start Position Eb9M;u  
long nEndPos; //File Snippet End Position j8p'B-yS  
int nThreadID; //Thread's ID #D!3a%u0  
boolean bDownOver = false; //Downing is over =j~}];I  
boolean bStop = false; //Stop identical kC[nY  
FileAccessI fileAccessI = null; //File Access interface e3>k"  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException gM3gc;  
{ ^SRa!8z$W  
this.sURL = sURL; %x7l`.)N  
this.nStartPos = nStart; N:/$N@"Ge  
this.nEndPos = nEnd; ( ]o6Pi  
nThreadID = id; -.WVuc`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 P^LOrLmo8  
} `o*g2fW!  
-nT+!3A8  
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public void run() Bf88f<Z  
{ 7+u%]D!  
while(nStartPos < nEndPos && !bStop) 5cQBqH]   
{ _>:g&pS/  
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try{ @kwD$%*0  
URL url = new URL(sURL);  )Bk?"q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); z_l3=7R  
httpConnection.setRequestProperty("User-Agent","NetFox"); Lou4M  
String sProperty = "bytes="+nStartPos+"-"; T[q-$8U  
httpConnection.setRequestProperty("RANGE",sProperty); +;[`fSi  
Utility.log(sProperty); KwQO,($,]  
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InputStream input = httpConnection.getInputStream();

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//logResponseHead(httpConnection); e#HP+b$  
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byte[] b = new byte[1024]; Dfhs@ z  
int nRead; HIa$0g0J  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5!ReW39c;  
{ fF[g%?w  
nStartPos += fileAccessI.write(b,0,nRead); lIFU7g  
//if(nThreadID == 1) )#ujF~w>  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nG%j4r ;  
} 'qd")  
"^D6%I#T  
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Utility.log("Thread " + nThreadID + " is over!"); N~ozyIP,  
bDownOver = true; #*]= %-A  
//nPos = fileAccessI.write (b,0,nRead); *-Yw0Y[E  
} 3CHte*NL=  
catch(Exception e){e.printStackTrace ();} ^c7L!F  
} anwn!Eqk"  
} 3z#;0n
}  
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9,c>H6R7  
//打印回应的头信息 Q8~
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public void logResponseHead(HttpURLConnection con) >PJ-Z~O'   
{ DJW1kR  
for(int i=1;;i++) tj&A@\/  
{ A{o{o++  
String header=con.getHeaderFieldKey(i); -?'CUm*Od  
if(header!=null) FTenXJ/c  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `3:%F>  
Utility.log(header+" : "+con.getHeaderField(header)); _#F'rl6'  
else .eAC!R  
break; e4b~s  
} ,'673PR  
} 
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!jW32$YTR  
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public void splitterStop() F1=+<]!  
{ )pLq^j  
bStop = true; W<L6,  
} HKkf+)%)x  
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} kt#W~n  
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/* [s2V-'2  
**FileAccess.java u3:Qt2^S  
*//文件访问(定位，写) TfVD'HAN;l  
package NetFox; }(K6 YL  
import java.io.*; \G@6jn1G(  
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public class FileAccessI implements Serializable{ ,9qB}HG  
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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 7]j-zv  
RandomAccessFile oSavedFile; PuJ{!S\T7  
long nPos; |mmG s  
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public FileAccessI() throws IOException }YP7x|  
{ Zbh]OCN  
this("",0); ] <3?=$  
} 1>VS/H`  
gj,J3x4TK/  
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public FileAccessI(String sName,long nPos) throws IOException 5]l7Z35  
{ E$Pjp oQTf  
oSavedFile = new RandomAccessFile(sName,"rw"); b6vYM_ Q  
this.nPos = nPos; TrU@mYnE  
oSavedFile.seek(nPos); d$rUxqB.  
} KBR0p&MN  
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public synchronized int write(byte[] b,int nStart,int nLen) y32++b!  
{ IWo~s  
int n = -1; aSkx#mV  
try{ j& iL5J;  
oSavedFile.write(b,nStart,nLen); 0"psKf'  
n = nLen; -5v.1y=!L  
}  7EP|X.  
catch(IOException e) G+ v, Hi1  
{ `u\z!x'  
e.printStackTrace (); hdtnC29$  
} ;c- ]bhBB  
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return n; M:Y*Tb6w  
} uy _i{Y|  
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} Kq 4<l  
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)d(0Y<e@  
/* (vAv^A*i}  
**SiteInfoBean.java n R\n\
  
*/ XMEK5Z9Dd  
package NetFox; 'uf2 nUo  
n!ZP?]FR  
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public class SiteInfoBean { HKiVEg  
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private String sSiteURL; //Site's URL P,/13tZ#3  
private String sFilePath; //Saved File's Path J[!x%8m  
private String sFileName; //Saved File's Name J7ktfyQ0W  
private int nSplitter; //Count of Splited Downloading File 974eY  
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public SiteInfoBean() j!S1Y0CV  
{//nSplitter的缺省值为5 nR o=J5tY  
//default value of nSplitter is 5 L8:]`MQ0  
this("","","",5);
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} gj[ >p=Wn  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &gWMl`3^*!  
{ L{2
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sSiteURL= sURL; |I}A>XG  
sFilePath = sPath;
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sFileName = sName; (F,(]71Z+  
this.nSplitter = nSpiltter; /[Bl  
E
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} ~>#LOT `  
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public String getSSiteURL() (|g").L  
{ _x\-!&[p  
return sSiteURL; $R%+*  
} j6tP)f^tD  
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@A [)hk&(R  
public void setSSiteURL(String value) a
9#W9
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{ u?q&K|  
sSiteURL = value; N@cMM1  
} W[R]^2QAG  
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Lzh9DYU6  
public String getSFilePath() OM20-KDc5  
{ _Fy4DVCg  
return sFilePath; I:F'S#  
} G%2P  
4@
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public void setSFilePath(String value) [urH a  
{ ,3:QB_  
sFilePath = value; 4dW3'"R"L  
} 7'_nc!ME  
':,>eL#+uV  
3hc#FmLr2b  
public String getSFileName() uyL72($  
{  ;e&
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return sFileName; HjV\lcK:v  
} jo_o`j  
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"3@KRb4f  
public void setSFileName(String value) :tKbz nd/  
{ PPN q:,  
sFileName = value; kfVZ=`p}  
} ^[en3aQ  
7.%f01/i  
5+`=t07^et  
public int getNSplitter() ?#4+r_dP  
{ 0HjJaML  
return nSplitter; j\
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} /[0F6  
F\JLbY{x]  

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public void setNSplitter(int nCount) O8gfiQqF&  
{ 2.]~*7   
nSplitter = nCount; . /Y&\<  
} o5>/}wIf  
} "s% 686Vz  
658\#x8|  
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/* g+.0c=G(  
**Utility.java 9-b 8`|s  
*/ (JWv *p  
package NetFox; C]/&vh7ta  
rrAqI$6  
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public class Utility { =m~ruZ/  
E&'#=K[  
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public Utility() |IAW{_9)U  
{ {b2 aL7  
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b]w[*<f?  
} `T=1<Twc  
aF!WIvir  
//线程睡眠 _@
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public static void sleep(int nSecond) Z&A0hI4d  
{ I :@|^PYw  
try{ l/M[am  
Thread.sleep(nSecond); ]9s\_A9  
} 9l#gMFknI  
catch(Exception e) l**3%cTb  
{ 2Q}7fht  
e.printStackTrace (); D!S8oKW  
} T
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} \TZ|S,FS  
$
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//日志 FJ}gUs{m  
public static void log(String sMsg) |WBZN1W)  
{ Wa<-AZn
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System.err.println(sMsg); nn'Af,ko/  
} u3ST;  
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@gEr+O1K(  
public static void log(int sMsg) AC'lS >7s  
{ 0X#+#[W  
System.err.println(sMsg); 6m@0;Ht  
} 'mJ1
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} Bh,Q8%\6  
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/* {pC\\}  
**TestMethod.java cl_TF[n?  
*/ G1/Gq.<  
package NetFox; *{4 ETr7  
S}b~_}  
o[oqPN3$Y  
public class TestMethod { ]);NnsG  
c})wD+1  
_N@(Y:  
public TestMethod() w,/6B&|  
{ ///xx/weblogic60b2_win.exe E<k^S{  
try{ Qh8C,"a  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =9<$eLE0  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ]VDn'@uM  
SiteFileFetch fileFetch = new SiteFileFetch(bean); N8QH*FX/F1  
fileFetch.start(); ,_bp)-OG  
} qX?[mdCHZ  
catch(Exception e){e.printStackTrace ();} \OY}GR
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} x)5LT}p  
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public static void main(String[] args) "&<~UiI  
{ =Epq%,4nG  
new TestMethod(); He<;4?:  
} Yt*vqm[WV  
} ST% T =_q  
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