http断点续传简单实现（java)

/* %\PnsnJ9Q  
**SiteFileFetch.java c7T9kV8hS  
*/ x'*,~u  
package NetFox; eA9U|&o  
import java.io.*; <Ur(< WTV  
import java.net.*; E< nXkqD  
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public class SiteFileFetch extends Thread { %||}WT-wv  
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SiteInfoBean siteInfoBean = null; //文件信息Bean :Z(?Ct&8  
long[] nStartPos; //开始位置 |5)~WoV/G  
long[] nEndPos; //结束位置 r*]0PQ{?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 86O"w*9  
long nFileLength; //文件长度 s mub> V  
boolean bFirst = true; //是否第一次取文件 ;;'b;,/  
boolean bStop = false; //停止标志 f%9EZ+OP  
File tmpFile; //文件下载的临时信息 8>a/x,  
DataOutputStream output; //输出到文件的输出流 OD<0,r0f,  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） /9dV!u!;  
public SiteFileFetch(SiteInfoBean bean) throws IOException I7b(fc-r  
{ ZxkX\gl91  
siteInfoBean = bean; ,t5X'sY L  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *9)7.}uY  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");
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if(tmpFile.exists ()) k7P~*ll$  
{ aVvi_cau  
bFirst = false; l=*^FK]L`  
read_nPos(); |sz`w^#  
} Ib.`2@o&  
else 'JY*K:-  
{ Zzr+p.  
nStartPos = new long[bean.getNSplitter()]; w] LN(o:  
nEndPos = new long[bean.getNSplitter()]; f"Yj'`6  
} j{N;2#.u  
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} c/ %5IhX?  
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public void run() U~Aw=h5SD  
{ ^zkTV_,cRp  
//获得文件长度 , RfU1R  
//分割文件 &3v{~Xg)  
//实例FileSplitterFetch L^rtypkJ  
//启动FileSplitterFetch线程 {L
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//等待子线程返回 Qfo'w%px  
try{ k9UmTvX  
if(bFirst) pWH
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{ %lNWaA  
nFileLength = getFileSize(); E }|g3  
if(nFileLength == -1) w=\Lw+X  
{ "T5?<c  
System.err.println("File Length is not known!"); :/ns/~5xa:  
} OO_{o  
else if(nFileLength == -2) 3P Twpq1  
{ 0K7]<\)  
System.err.println("File is not access!"); zNR
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} lqAU5K{wQ  
else K1uN(T.Ju  
{ 6,M>'s,N  
for(int i=0;i<nStartPos.length;i++) ==(9P`\  
{ ,$5;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); uxk&5RY  
} =]oBBokV  
for(int i=0;i<nEndPos.length-1;i++) _
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nEndPos = nStartPos[i+1]; L5%~H?K(  
} >`= '~y8  
nEndPos[nEndPos.length-1] = nFileLength; M]!\X6<_  
} w<j6ln+nM  
} ;+K:^*oJ  
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@;_r`AT7  
//启动子线程 DU$]e1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; &w:"e'FG`  
for(int i=0;i<nStartPos.length;i++) 0:Js{$ZL4  
{ kM]:~
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,0[8/)$M  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), xr!FDfM.K  
nStartPos,nEndPos,i); is{I5IR\/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1JgnuBX"  
fileSplitterFetch.start(); mB;W9[  
} <oV _EZ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), i:OD)l  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); lT$Vv=M  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", tr7FV1p  
nEndPos = " + nFileLength); z_!P0`  
// fileSplitterFetch[nPos.length-1].start(); hd9fD[5  
AM##:4   
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//等待子线程结束 TJ7on
.;  
//int count = 0; lE08UEk1i  
//是否结束while循环 }txHuq1Q.  
boolean breakWhile = false; K"eR6_k  
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while(!bStop) 2i', e  
{ #^<7VS!x  
write_nPos(); h0Acpd2  
Utility.sleep(500); nXK"BYe  
breakWhile = true; 5ej
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for(int i=0;i<nStartPos.length;i++) JO5~Vj_"  
{ ]eb9Fq:N7  
if(!fileSplitterFetch.bDownOver) Lcplc"C  
{ 9C[3w[G~C  
breakWhile = false; Zp@p9][C  
break; Rb<aCX  
} 3s\2 9gq  
} hnL"f[p@gC  
if(breakWhile) LYGFEjS[  
break; V!c
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//count++; G9z Q{E  
//if(count>4) 0KnlomuH2  
// siteStop(); g6Qzkvw)  
} ko im@B  
1 dz&J\|E#  
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System.err.println("文件下载结束！"); tbAN{pX  
} !OPK?7  
catch(Exception e){e.printStackTrace ();} $q DH  
} Gw!jYnU  
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//获得文件长度 @`k!7? Sq  
public long getFileSize() Ee9u7TFT  
{ s?=f,I  
int nFileLength = -1; ,bmiIW%  
try{ #g4X`AHB  
URL url = new URL(siteInfoBean.getSSiteURL()); nfy"M),et  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8
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httpConnection.setRequestProperty("User-Agent","NetFox"); dSsMa3X[n  
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int responseCode=httpConnection.getResponseCode(); Vj0`*nC)/  
if(responseCode>=400) >~TLgq*  
{ XIJ>\ RF  
processErrorCode(responseCode); -:pLlN-f  
return -2; //-2 represent access is error + R])u5c'  
} 4xT(Uj  
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String sHeader; [@#P3g\:>W  
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for(int i=1;;i++) 7 -gt V#  
{ qB3 SQ:y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); J.?6a:#bU/  
//Utility.log(in.readLine()); tLS5yT/  
sHeader=httpConnection.getHeaderFieldKey(i); DB:Ia5|*i  
if(sHeader!=null) DDN#w<#  
{ LEc%BQx  
if(sHeader.equals("Content-Length")) cc.zC3Hs3  
{ q3T'rw%Eh  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ocAoqjlT[  
break; AmRppbj/wO  
} Z)|*mJ  
} j9) Z'L  
else <2diO=  
break; `t{aN|3V[  
} vov"60K  
} -2K`:}\y&  
catch(IOException e){e.printStackTrace ();} 4tCyd5u a8  
catch(Exception e){e.printStackTrace ();} 7>wSbAR<  
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Utility.log(nFileLength); IBQmm(+v  
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return nFileLength; Xko[Z;4v8'  
} K)sO  
opjrU$<]N  
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//保存下载信息（文件指针位置） op"RrZAZBT  
private void write_nPos() My:wA;#  
{ 1r\? uD  
try{ N#6&t8;kTC  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2y,NT|jp  
output.writeInt(nStartPos.length); mj%Iow.  
for(int i=0;i<nStartPos.length;i++) }Wn6r_:  
{ ?#rDoYt/Sx  
// output.writeLong(nPos); $wdIOfaH  
output.writeLong(fileSplitterFetch.nStartPos); :a0qm.EN  
output.writeLong(fileSplitterFetch.nEndPos); c3`X19'%fM  
} ka[]pY  
output.close(); zRD{"uqi  
} z4&|~-m,  
catch(IOException e){e.printStackTrace ();} (JL{X`gs#  
catch(Exception e){e.printStackTrace ();} y2TJDb1  
} P
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//读取保存的下载信息（文件指针位置） g
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private void read_nPos() jQj`GnN|  
{ d
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try{ (m-(5 CaJ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); D5]T.8kX(7  
int nCount = input.readInt(); My5h;N@C  
nStartPos = new long[nCount]; BQ)zm  
nEndPos = new long[nCount]; pI( OI>~3  
for(int i=0;i<nStartPos.length;i++) L@ql)Lc);  
{ H--(zxK  
nStartPos = input.readLong(); ,-vbR&  
nEndPos = input.readLong(); ZxwI< T:&  
} +'N?`l6<  
input.close(); Z81]>  
} i?A4uyYwS  
catch(IOException e){e.printStackTrace ();} :jT1=PfL  
catch(Exception e){e.printStackTrace ();} U9y[b82  
} ](aXZ<,  
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private void processErrorCode(int nErrorCode) `CUTb*{`  
{ -nV]%vJ$R}  
System.err.println("Error Code : " + nErrorCode); :&/'rMi<T  
} 3*/y<Z'H  
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=CFO
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//停止文件下载 eXc`"T,C.  
public void siteStop() :,fs'!  
{ }<[@)g.h.  
bStop = true; ;xN4L  
for(int i=0;i<nStartPos.length;i++) f-k%P$"X&  
fileSplitterFetch.splitterStop(); lN<v
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} q#xoM1  
} >j4;{r+eQw  
//负责部分文件的抓取 MQG(n+c  
**FileSplitterFetch.java H]H*Ouu["e  
*/ _<+!  
package NetFox; .Lr;{B  
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import java.io.*; D2#3fM6  
import java.net.*; &_x:+{06  
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public class FileSplitterFetch extends Thread { MXh0a@*]  
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String sURL; //File URL c/jU+,_g  
long nStartPos; //File Snippet Start Position "iMuA  
long nEndPos; //File Snippet End Position %d c=QSL  
int nThreadID; //Thread's ID +g(>]!swb  
boolean bDownOver = false; //Downing is over [d`J2^z}  
boolean bStop = false; //Stop identical @>}!g9c  
FileAccessI fileAccessI = null; //File Access interface l:-$ulAx  
3,8<5)ds*  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %?Yf!)owh  
{ w<!F& kQB  
this.sURL = sURL; V8@VR`!'  
this.nStartPos = nStart; fZw/kjx@  
this.nEndPos = nEnd; p9 <XaJ}  
nThreadID = id; 1Mn=m w  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 DI{VJ&n66  
} E z?O gE{  
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public void run() )"/.2
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{ v-B{7 ~=#Z  
while(nStartPos < nEndPos && !bStop) mSm:>hBd  
{ 8oK*NB29  
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try{ oCg|* c|+  
URL url = new URL(sURL); Y``50{7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -GJ~xcf0  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~2PD%+e7]  
String sProperty = "bytes="+nStartPos+"-"; s;Q0  
httpConnection.setRequestProperty("RANGE",sProperty); `|)V]<  
Utility.log(sProperty); {$-lXw4  
(HbA?Aja  
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InputStream input = httpConnection.getInputStream(); -N $4\yp  
//logResponseHead(httpConnection); :[xFp}w{  
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byte[] b = new byte[1024]; ?l/VCEZP  
int nRead; [1nfSW  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) $ @g\wz  
{ d0``:  
nStartPos += fileAccessI.write(b,0,nRead); S3 12#X(%  
//if(nThreadID == 1) (yA`h@@WS  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \e+h">`WgX  
} /*Iq,"kGz  
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Utility.log("Thread " + nThreadID + " is over!"); vX1 8 ]  
bDownOver = true; >!sxX = <  
//nPos = fileAccessI.write (b,0,nRead); h*d1G9%Q1  
} KG<. s<  
catch(Exception e){e.printStackTrace ();} yw
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} S9RH&/^H  
} yhm
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//打印回应的头信息 \GYrPf$  
public void logResponseHead(HttpURLConnection con) gr
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{ O:%s;p 5  
for(int i=1;;i++) !-rG1VI_S*  
{ mO<1&{qMZ  
String header=con.getHeaderFieldKey(i); y/i{6P2`,D  
if(header!=null) B0E`C  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); c(W
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Utility.log(header+" : "+con.getHeaderField(header)); H j [!F%  
else _Ns/#Xe/  
break; lldNIL6B%  
} M5 \flE2  
} C- 5QhD  
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public void splitterStop() gZq_BY_U  
{ h'lqj0  
bStop = true; K}|zKTh:?  
} 59Lc-JJ  
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} W{A4*{  
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/* 6mV-+CnYC  
**FileAccess.java w1Txz4JqB  
*//文件访问(定位，写) )iX2r{  
package NetFox; U}T{r%9  
import java.io.*; moS0y?N  
9]C%2!Ur,  
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public class FileAccessI implements Serializable{ "w&IO}j;=  
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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 a\-AGG{2/X  
RandomAccessFile oSavedFile; :A7\eN5  
long nPos; dJv2tVm&'  
?}RPnf  
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public FileAccessI() throws IOException t =V| '  
{ 3c%_RI.  
this("",0); m^%@bu,  
} e&nE  
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)
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public FileAccessI(String sName,long nPos) throws IOException y0f:N U  
{ R_W6}  
oSavedFile = new RandomAccessFile(sName,"rw"); :W^\ }UX4  
this.nPos = nPos; | |"W=E  
oSavedFile.seek(nPos); 1-V"uLy@gC  
} D*&#}c,*  
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public synchronized int write(byte[] b,int nStart,int nLen) `L LS|S]  
{ \VpN:RI  
int n = -1; BItH0r7  
try{ RDfvD|}VN  
oSavedFile.write(b,nStart,nLen); )x+P9|  
n = nLen; '8Cg2v5&w  
} =kTHfdin&  
catch(IOException e) [*C%u_h  
{  WD55(  
e.printStackTrace (); /:tzSKq}  
} fUMjLA|*I<  
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return n; W_L*S4 ~  
} w_h{6Kc<  
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} 3xk_ZK82  
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/* EXMW,  
**SiteInfoBean.java !9.k%B:  
*/ QJ&]4*>a  
package NetFox; STl8h}C  
-Ew>3Q  
E
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public class SiteInfoBean { b(oe^jeGz  
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private String sSiteURL; //Site's URL :i4AkBNK  
private String sFilePath; //Saved File's Path 0K'{w]Q  
private String sFileName; //Saved File's Name 5vFM0  
private int nSplitter; //Count of Splited Downloading File  zo1T`"Y  
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public SiteInfoBean() D6~KLSKm  
{//nSplitter的缺省值为5 Wv|CJN
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//default value of nSplitter is 5 LC4VlfU  
this("","","",5); r?itd)WC<X  
} =+
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) AR!v%Z49i  
{ NE.h/+4  
sSiteURL= sURL; v%$l(  
sFilePath = sPath; OK)>QGl  
sFileName = sName; wz1nV}  
this.nSplitter = nSpiltter; oi m7=I0  
p5jR;nOZ%l  
~/X8Hy!-  
} Siq]Ii0F;>  
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>?1GJ5]\s  
public String getSSiteURL() udT0`6l;  
{ fF(AvMsO  
return sSiteURL; O=t~.]))  
} ~5&B#Sm[G  
\6
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public void setSSiteURL(String value) tA^+RO4  
{ T$`m!mQ4  
sSiteURL = value; S{?l/*Il*_  
} aGBd~y@e  
1d~d1Rd  
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public String getSFilePath() (a0(ZOKH  
{ Mk~U/oq  
return sFilePath; e]nP
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} oKYa?  
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'Kk/ J+6U  
public void setSFilePath(String value) >;XtJJS  
{ [ :)
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sFilePath = value; CuK>1_Dq  
} hP8w3gl
_  
0r_~LN^|[  
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public String getSFileName() ]h
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{ i9Beap/t$  
return sFileName; 0J^Z)U>j  
} H#7=s{u  
*Lxt{z`9  
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public void setSFileName(String value) wm^1Fn--  
{ 
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sFileName = value; SOE-Kio=B  
} SHs [te[  
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public int getNSplitter() z:Tj0<A'  
{ n-2!<`UFX  
return nSplitter; tH&eKM4
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} [<5/s$,i  
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public void setNSplitter(int nCount) 
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{ w_o+;B|I  
nSplitter = nCount; bl
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} YhNrg?nS  
}
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:!l.ze{F  
/* $W=)-X\>  
**Utility.java vs$h&o>|  
*/ qLN\>Z,3;  
package NetFox; h^_^)P+;  
hSxK*.W*3  
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public class Utility { R<_VWPlj  
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public Utility() n-SO201[*  
{ BriL^]  
#'O9Hn({  
:%33m'EV}  
} @GD $KR9  
?*$uj(  
//线程睡眠 lz6CK  
public static void sleep(int nSecond) n|?sNM<J3  
{ zRmVV}b  
try{ H;NAS/OhS  
Thread.sleep(nSecond); ?]bx]Y;
 
} ZbVn"he  
catch(Exception e) )X," NJG  
{ y`8U0TE3R  
e.printStackTrace (); Ym"^Ds}  
} I L7kpH+y  
} Du +_dr^4  
QHja4/
 
//日志 WF*j^ %5  
public static void log(String sMsg) ?$ov9U_  
{ Dq%}({+  
System.err.println(sMsg); )7!,_r  
} %QrOEs  
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x^c,cV+*  
public static void log(int sMsg) E
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{ a#+$.e5  
System.err.println(sMsg); KztQT9kY  
} Sh5)36  
} h5T~dGRlR  
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j~S=kYrGM  
/* g"Hl 30o  
**TestMethod.java 3?<A]"X.  
*/ }6pr.-J  
package NetFox; h4itXJy52B  
5(\/ b<#  
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public class TestMethod { zt9A-% \R  
g18zo~LZ  
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public TestMethod() g~,iWoY  
{ ///xx/weblogic60b2_win.exe t'J4zV  
try{ 82+2PE{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 'LuxF1>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _a9oHg  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %-$ :/N  
fileFetch.start(); 5M9o(Z\AF  
} kG9aHWw  
catch(Exception e){e.printStackTrace ();} >EA\KrjW  
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} LttA8hf5q?  
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,4
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public static void main(String[] args) ,Xn%0]  
{ p ^TCr<=  
new TestMethod(); ^~TE$i<  
} 7JuHa /Mv  
} kREFh4QO,  
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