http断点续传简单实现（java)

/* P(N$U^pj  
**SiteFileFetch.java ]A*v\Qy  
*/ G4Y]fzC  
package NetFox; b.jxkx\nt  
import java.io.*; ,XmTKO
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import java.net.*; NNUm
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public class SiteFileFetch extends Thread { C`|'+  
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SiteInfoBean siteInfoBean = null; //文件信息Bean NG!~<Kx  
long[] nStartPos; //开始位置 !
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long[] nEndPos; //结束位置 )KvQaC  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 m*VM1kV  
long nFileLength; //文件长度 1EW-%GQO  
boolean bFirst = true; //是否第一次取文件 S&BJR!FQ  
boolean bStop = false; //停止标志 3e)3t`  
File tmpFile; //文件下载的临时信息 v6{qKpU#  
DataOutputStream output; //输出到文件的输出流 gHS;RF9  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） -QaS/WO_  
public SiteFileFetch(SiteInfoBean bean) throws IOException Q+4
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{ E3N4(V\*  
siteInfoBean = bean; =\IcUY,4
 
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); VU>s{_|{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); mtEE,O!+  
if(tmpFile.exists ()) *.ffyBI*~  
{ ^FLuhLS\*  
bFirst = false; .F
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read_nPos(); Y4PU~l  
} Q7PqN1jTE  
else %;,D:Tv=&  
{ |0Kj0u8T  
nStartPos = new long[bean.getNSplitter()]; Q!DQ!;Br6  
nEndPos = new long[bean.getNSplitter()]; m4:b?[  
} F8 4LMk?U  
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} /wIev1Z!Y  
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public void run() 3mWd?!+m=  
{ #mqz*=L3  
//获得文件长度 NJ-cP m  
//分割文件 7{oG4X!  
//实例FileSplitterFetch SZ}t_w `  
//启动FileSplitterFetch线程 \IQP`JR  
//等待子线程返回 rnxO2   
try{ -0| '{  
if(bFirst) ;FYiXK%  
{ luZqW`?Bt  
nFileLength = getFileSize(); Yyl2J#$!  
if(nFileLength == -1) VHsNz WI  
{ %^RlE@l9  
System.err.println("File Length is not known!"); r]1|I6:&)  
} g<~[k?~J  
else if(nFileLength == -2) Tr}@fa  
{ Rkfr4  
System.err.println("File is not access!"); _:om(gL  
} zk]6|i$!I  
else (,\`?g  
{ uC G^,BQ  
for(int i=0;i<nStartPos.length;i++) %j=E}J<H5*  
{ cXcn}gKV  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8}p5MG  
} yS/ovd  
for(int i=0;i<nEndPos.length-1;i++) T8YqCT"EA<  
{ ,)+O.Lf7&.  
nEndPos = nStartPos[i+1]; j#%*@]>Tg  
} ->vfQwBFd  
nEndPos[nEndPos.length-1] = nFileLength; &Qghm o  
} 6m21Y8N  
} lfR"22t  
/B!"\0G/,  
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//启动子线程 GpF,=:  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >fo &H_a  
for(int i=0;i<nStartPos.length;i++) VIbm%b$~  
{ 9a)D
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Dbyy H_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), b]6;:Q!d  
nStartPos,nEndPos,i); />\.zuAr&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); J.
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fileSplitterFetch.start();  6" 3!9JC  
} HkxFDU-K  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;,*U,eV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); w`1qx;/!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", BU:s&+LYUv  
nEndPos = " + nFileLength); 451
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// fileSplitterFetch[nPos.length-1].start(); L~V 63K  
2!dIW5I  
UR-e'Z&]  
//等待子线程结束 7 pg8kq@  
//int count = 0; Uy ;oJY  
//是否结束while循环 =]7|*-  
boolean breakWhile = false; ]5td,2E
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while(!bStop) #eE:hiu<v  
{ u4o%qK  
write_nPos(); oB3>0Pm*a.  
Utility.sleep(500); 2ok>z$Y  
breakWhile = true; V0JoUyZ  
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for(int i=0;i<nStartPos.length;i++) aqs']  
{ x#dJH9NR[  
if(!fileSplitterFetch.bDownOver) @R}L 4  
{ $K<jmEC@<  
breakWhile = false; $yaE!.Kc  
break; r~nrP=-%  
} $.
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} }9P)<
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if(breakWhile) U$VT
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break; ;?inf`t  
f{ S)wE>;  
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//count++; 2T?t[;-  
//if(count>4) u[2R>=  
// siteStop(); #_7}O0?c3  
} {yVi/*;f^  
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System.err.println("文件下载结束！"); "hog A5
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} g;]2'Rj  
catch(Exception e){e.printStackTrace ();} pS%,wjb&P  
} )Y?Hf2']  
"@`
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,\
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//获得文件长度 Ev0V\tl>0  
public long getFileSize() =NJb9
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{ `!m+g0  
int nFileLength = -1; ['-ln)96.
 
try{ 
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URL url = new URL(siteInfoBean.getSSiteURL()); 7SAu">lI
l  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); L1)?5D  
httpConnection.setRequestProperty("User-Agent","NetFox"); >R!^aJ  
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int responseCode=httpConnection.getResponseCode(); >wcsJ{I  
if(responseCode>=400) F w{8MQ2  
{ Zb2 B5(0  
processErrorCode(responseCode); SCxzT}#J  
return -2; //-2 represent access is error <;9vwSH>  
} Vg[U4,  
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String sHeader; %t+V8A  
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for(int i=1;;i++) o]Vx6  
{ W97Ka}Y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); nsgNIE{>gO  
//Utility.log(in.readLine()); Vp5qul%  
sHeader=httpConnection.getHeaderFieldKey(i); s?%1/&.~  
if(sHeader!=null) YVW!u6W'[6  
{ vgE5(fJh  
if(sHeader.equals("Content-Length")) PI0/=kS  
{ fvNGGn!  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9MM4C  
break; yMz@-B  
} U7x}p^B9\N  
} "t_]Qu6  
else A;kAAM  
break; )_bXKYUX*0  
} ;ejC:3yO  
} yx/:<^"-$  
catch(IOException e){e.printStackTrace ();} NmtBn^t  
catch(Exception e){e.printStackTrace ();} 7^Onq0ym T  
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Utility.log(nFileLength); de ](l687I  
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return nFileLength; 'inWV* P*g  
} SKG_P)TnO  
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//保存下载信息（文件指针位置） |y'q`cY  
private void write_nPos() VCc4nn#  
{ U}Hmzb  
try{ c yN_Sg  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5jjJQ'  
output.writeInt(nStartPos.length); CtSAo\F  
for(int i=0;i<nStartPos.length;i++) F1Z20)8K  
{ A0[flIl  
// output.writeLong(nPos); yobi$mnsy!  
output.writeLong(fileSplitterFetch.nStartPos); U_I'Nz!^t  
output.writeLong(fileSplitterFetch.nEndPos); CB|z{(&N  
} FP9ZOoog  
output.close(); l_f"}l  
} oN _%oc  
catch(IOException e){e.printStackTrace ();} _r,#
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catch(Exception e){e.printStackTrace ();} kc"U)>  
} \*_a#4a  
![Jxh,f  
*2@q=R-1  
//读取保存的下载信息（文件指针位置） <,cDEN7  
private void read_nPos()  ;\iQZ~   
{ lXz<jt@5  
try{ $\P!
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .)W8 U [  
int nCount = input.readInt(); DDkOg]  
nStartPos = new long[nCount]; u-k*[!JU  
nEndPos = new long[nCount]; sHEISNj/^  
for(int i=0;i<nStartPos.length;i++) g" M1HxlV  
{ yr;oq(&N  
nStartPos = input.readLong(); ;wv
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nEndPos = input.readLong(); O9>/WmLe  
} Vx#xq#wK  
input.close(); H-UMsT=g]  
} e@Mm4&f[p  
catch(IOException e){e.printStackTrace ();} 
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catch(Exception e){e.printStackTrace ();} 14^t{  
} o^AK@\e:^Z  
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private void processErrorCode(int nErrorCode) t~bjDV^`  
{ \{~x<<qFd  
System.err.println("Error Code : " + nErrorCode); +w}5-8mH&>  
} a{u)~:/G  
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]
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//停止文件下载 1P[!B[;c  
public void siteStop() 2&Efqy8}DZ  
{ ~^3B(feQ]  
bStop = true; s'K0C8'U  
for(int i=0;i<nStartPos.length;i++) ^R2:Z&Iv%  
fileSplitterFetch.splitterStop(); 4QDF%#~q^  
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} .Wa6?r<g  
} n ~ =]/  
//负责部分文件的抓取 n$~RgCf  
**FileSplitterFetch.java _|s{G  
*/ @w|~:>/g  
package NetFox; k
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import java.io.*; u37+B  
import java.net.*; ;xj
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public class FileSplitterFetch extends Thread { 2 K` hH  
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String sURL; //File URL u/,m2N9cL  
long nStartPos; //File Snippet Start Position jNB-FVaT  
long nEndPos; //File Snippet End Position ZB%7Sr0  
int nThreadID; //Thread's ID w1iQ#.4K_  
boolean bDownOver = false; //Downing is over 9RAN$\AKy  
boolean bStop = false; //Stop identical 8~
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FileAccessI fileAccessI = null; //File Access interface 7W 4[1  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?N`W,  
{ EW YpYMkm  
this.sURL = sURL; YgVZq\AV"  
this.nStartPos = nStart; Y%Saz+  
this.nEndPos = nEnd; =k&'ft  
nThreadID = id; ,{]>U'-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 cvAkP2  
} %7hYl'83  
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public void run() \bfNki  
{ XV!P8n  
while(nStartPos < nEndPos && !bStop) :]?I|.a  
{ 7@06x+!  
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try{ 7<X_
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URL url = new URL(sURL); kkh#VGh"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `qUmOFl  
httpConnection.setRequestProperty("User-Agent","NetFox"); `A?/Ww>;  
String sProperty = "bytes="+nStartPos+"-"; Plt~l3_  
httpConnection.setRequestProperty("RANGE",sProperty); /J5wwQ (:  
Utility.log(sProperty); LnM+,cBz  
,.DU)Wi?}  
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InputStream input = httpConnection.getInputStream(); `@eQL[Z9x  
//logResponseHead(httpConnection); [x9eamJ,H  
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byte[] b = new byte[1024]; NO;+:0n  
int nRead; B6|=kl2C  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Vbz$dpT  
{ *n}{)Ef  
nStartPos += fileAccessI.write(b,0,nRead); [{'` |  
//if(nThreadID == 1)  X&(1DE  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]BX|G`CCc  
} I)n%aTfo8  
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Utility.log("Thread " + nThreadID + " is over!"); f`vB$r>  
bDownOver = true; ])vM# f  
//nPos = fileAccessI.write (b,0,nRead); z,$^|'pP  
} Dy0RZF4_  
catch(Exception e){e.printStackTrace ();} i?||R|>;"'  
} 5Vf#
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} na>UF
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//打印回应的头信息 n{=vP`V_  
public void logResponseHead(HttpURLConnection con) ~#OnA1)  
{ +.gZILw  
for(int i=1;;i++) !$Nh:(>:  
{ | [P!9e  
String header=con.getHeaderFieldKey(i); C+jlIT+  
if(header!=null) N9idk}T  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); O*T(aM3r  
Utility.log(header+" : "+con.getHeaderField(header)); ,D;d#fJ  
else Pe~[qETv  
break; X`#vH8  
} REc69Y.k  
} THkg,*;:  
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public void splitterStop() j%Usui<DL  
{ +<&_1%5+  
bStop = true; g \&Z_  
} `l'z#\  
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} |!,;IoZ  
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/
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/* <0T|RhbY  
**FileAccess.java 6 -N 442  
*//文件访问(定位，写) (gQP_Oa(  
package NetFox; Rcc9Tx(zvQ  
import java.io.*; xo a1='  
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public class FileAccessI implements Serializable{ ~5q1zr)E  
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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 F}wy7s2i  
RandomAccessFile oSavedFile; Z8%?ej`8  
long nPos; pE,2pT2>  
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9$$dSN\&  
public FileAccessI() throws IOException ]{s0/(EA  
{ lK 5@qG#  
this("",0); Qzt'ZK  
} ~}pc&jz>q  
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public FileAccessI(String sName,long nPos) throws IOException %|AebxB'o  
{ jmPnUn  
oSavedFile = new RandomAccessFile(sName,"rw"); |Bz1u|uc  
this.nPos = nPos; [;t-XC?[nk  
oSavedFile.seek(nPos); J2adG+=  
} \|&KD  
N?`V;`[  
>J*x` a3Q  
public synchronized int write(byte[] b,int nStart,int nLen) ct`j7[  
{ rP|~d}+I  
int n = -1; #9zpJ
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try{ y)vK=,"  
oSavedFile.write(b,nStart,nLen); /#jH#f[  
n = nLen; 6I2`oag  
} eu={6/O
 
catch(IOException e) `Y O(C<r-  
{ & 6'Rc#\P  
e.printStackTrace (); sPX&XqWx  
} ,.9k)\/V  
}C4wED.  
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return n; 6~c#G{kc  
} ,_iq$I;  
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} Co>e<be%S  
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/* f7YBhF  
**SiteInfoBean.java h4Wt oE>i  
*/ d|?Xo\+  
package NetFox; UodBK7y  
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public class SiteInfoBean { $vrkxn  
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private String sSiteURL; //Site's URL L4,b
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private String sFilePath; //Saved File's Path 'X<4";$mU  
private String sFileName; //Saved File's Name m8@&-,T   
private int nSplitter; //Count of Splited Downloading File ] # VHx  
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@}=(4%  
public SiteInfoBean() Nv=78O1  
{//nSplitter的缺省值为5 &1(- 8z*  
//default value of nSplitter is 5 nv0\On7wd  
this("","","",5); /~MH]Gh  
} o^XDG^35`  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) KL3Z(  
{ > vdmN]  
sSiteURL= sURL; >H^#!eaqw  
sFilePath = sPath; gk6UV2nE?  
sFileName = sName; v3#,Z!  
this.nSplitter = nSpiltter; {j=`  
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} N_IKH)  
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public String getSSiteURL() lD[
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{ _0(%^5
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return sSiteURL; om`T/@_,  
} V"m S$MN  
y~fKLIoz"  
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public void setSSiteURL(String value) fqhL"Ah   
{ P0e-v0  
sSiteURL = value; jMgXIK\  
} GlnO8cAB  
s bj/d~$N  
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public String getSFilePath() Keozn*fzI  
{ 'C/yQvJ  
return sFilePath; <XIIT-b[  
} qT48Y  
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public void setSFilePath(String value) MC* Hl`C  
{ ^cm] [9  
sFilePath = value; ZUHRATT-  
} T9C_=0(hn  
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public String getSFileName() 6Q^~O*cw  
{ +{1.kb Zq  
return sFileName; I|U'@E  
} .E<nQWz8  
;$QC_l''b  
L-T,[;bl  
public void setSFileName(String value) DcW?L^Mst  
{ <.Ws; HN}  
sFileName = value; 1Y|a:){G  
} j-":>}oW2.  
` y\)X C7  
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public int getNSplitter() 8.i4QaU  
{ uMJ\  
return nSplitter; /]_t->  
} <7M-?g:vj  
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L5-|-PP|;  
public void setNSplitter(int nCount) MKl0 d  
{ TxX=(7V  
nSplitter = nCount; s_'&_>D  
}
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} 3 r&  
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/* %GHGd'KO&  
**Utility.java T#))
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*/ 7;s#QqG`I  
package NetFox; Y()"2CCV  
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public class Utility { 8R,<S-+v  
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public Utility() ~SnUnNDm`  
{ J
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ilA45
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} 0NXH449I=  
5% 2A[B  
//线程睡眠 }yz>(Pq  
public static void sleep(int nSecond) V ~C$|+>e  
{ ffZ~r%25{  
try{ ;2p+i/sVj  
Thread.sleep(nSecond); tAdE<).!  
} _)M,p@!?=h  
catch(Exception e) F$C6( C?  
{ |eqBCZn  
e.printStackTrace (); \D7bTn  
} qqrjI.  
} V'Gal`  
'X^auyL  
//日志 Y`;}w}EcgR  
public static void log(String sMsg) Y%pab/Y  
{ CKYg!\g(:  
System.err.println(sMsg); +0'F@l  
} fw%`[(hK  
CSO'``16  
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public static void log(int sMsg) jJy:/!i  
{ EB~]6.1  
System.err.println(sMsg); ?sf<cFF  
} 1E+12{~m"i  
} g!'R}y  
>|$]=e,Z  
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/* @(3F4Z.i%.  
**TestMethod.java CXa[%{[n  
*/ eb62(:=N6  
package NetFox; ?=VvFfv%  
(_T{Z>C/J  
6':iW~iI  
public class TestMethod { WYP;s7_  
;<[X\;|'  
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public TestMethod() ,T$ts  
{ ///xx/weblogic60b2_win.exe qJhsMo2
IH  
try{ 1Kg0y71"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); f7Gn$E|/r;  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ag-A}k>v  
SiteFileFetch fileFetch = new SiteFileFetch(bean); X8nos  
fileFetch.start(); o NtFYY  
} #9vC]Gm  
catch(Exception e){e.printStackTrace ();} Nwvlv{k'  
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} au
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public static void main(String[] args) YR%iZ"`*+O  
{ +r:g}iR  
new TestMethod(); oQ!M+sRmF  
} N[%u>!  
} T$4{fhV \  
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