http断点续传简单实现（java)

/* UHgW-N"  
**SiteFileFetch.java I~GHx5Dk  
*/ -TMg9M4  
package NetFox; 9m.MGJbQ_f  
import java.io.*; Wn{MY=5Y  
import java.net.*; v|
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public class SiteFileFetch extends Thread { 6p9 {z42  
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SiteInfoBean siteInfoBean = null; //文件信息Bean '#C5m#v  
long[] nStartPos; //开始位置 ce[ Maw  
long[] nEndPos; //结束位置 |xF!3GGms  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Gs\D`|3=  
long nFileLength; //文件长度 (tyky&$!  
boolean bFirst = true; //是否第一次取文件 GExr] 2r  
boolean bStop = false; //停止标志 kl1/(  
File tmpFile; //文件下载的临时信息 34QW^{dgE  
DataOutputStream output; //输出到文件的输出流 I7W`\d)  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） R^mkQb>m.  
public SiteFileFetch(SiteInfoBean bean) throws IOException Ob{Tn@  
{ 3Vbt(K  
siteInfoBean = bean; ({zWyl  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); UxxX8N  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); j#U,zsv:  
if(tmpFile.exists ()) @+0dgkJ  
{ Cmp5or6d  
bFirst = false; b!e0pFS;  
read_nPos(); LJ6l3)tpD  
} M0g=gmau  
else *+XiBho  
{ -u7NBtgUh  
nStartPos = new long[bean.getNSplitter()]; q
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nEndPos = new long[bean.getNSplitter()]; dBwoAq`'  
} mMvAA;  
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} ;%Px~g  
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public void run() ^ir)z@P?V  
{ O c.fvP^ZD  
//获得文件长度 O._\l?m  
//分割文件 R
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//实例FileSplitterFetch %ZcS"/gf  
//启动FileSplitterFetch线程 -k@1#c+z  
//等待子线程返回 W/3sJc9  
try{ vvG"rU  
if(bFirst) ExQ\qp3  
{  +hKs  
nFileLength = getFileSize(); Y9gw ('\w  
if(nFileLength == -1) p/88mMr  
{ 8rx|7  
System.err.println("File Length is not known!"); N:CQ$7T{ j  
} j0j!oj)7I  
else if(nFileLength == -2) c%WO#}r|  
{ xXc>YTK'  
System.err.println("File is not access!"); g*(z.  
} LuHRB}W  
else ;aj;(Z.p)  
{  WzoI0E`  
for(int i=0;i<nStartPos.length;i++) pF7N = mO  
{ <f`n[QD2z  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); }#-@5["-X  
} `qYii
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for(int i=0;i<nEndPos.length-1;i++) $2,tT;50g  
{ e&2,cQRFV  
nEndPos = nStartPos[i+1]; Te[v+jgLY,  
} E .28G2&  
nEndPos[nEndPos.length-1] = nFileLength; [& Z- *a  
} 1r};cY6  
} @?3^Ks_  
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_5H~1G%q  
//启动子线程 (~%NRH<\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3tCTPZy  
for(int i=0;i<nStartPos.length;i++) tjwnFqI  
{ D(;+my2  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), C #iZAR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2Wu`Dp;&l  
nStartPos,nEndPos,i); [\#ANA"  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Vfga%K%l F  
fileSplitterFetch.start(); y631;dU  
} 934j5D  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +7o1&D*v  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); P3]K'*Dyd  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", t0jE\6r  
nEndPos = " + nFileLength); IG# wY  
// fileSplitterFetch[nPos.length-1].start(); s9a`2Wm  
h=,hYz?]  
%#rtNDi  
//等待子线程结束 7K "1^  
//int count = 0; Lui6;NY  
//是否结束while循环 {lH'T1^m  
boolean breakWhile = false; rAAx]nQ@  
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while(!bStop) {hJCn*m_   
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write_nPos(); s+v9H10R
 
Utility.sleep(500); /&
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breakWhile = true; 1U#W=Fg'  
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for(int i=0;i<nStartPos.length;i++) B1J,4  
{ yf0v,]v[  
if(!fileSplitterFetch.bDownOver) pi~5}bF!a  
{ as]M%|/-I  
breakWhile = false; #O!2
 
break; b@&uwSv  
} f|M^UHt8*  
} K}cA%Y  
if(breakWhile) g-wE(L  
break; ,*U-o}{8C?  

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//count++; E"_{S.Wc  
//if(count>4) 1HKA`]D"p  
// siteStop(); 0?8>{!I  
} R[
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System.err.println("文件下载结束！"); )I3E  
} >;1w-n  
catch(Exception e){e.printStackTrace ();} pP1DR'  
} o-Dfud@  
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XVt;hO  
//获得文件长度 Y @'do)  
public long getFileSize() ]T'8O`  
{ "i(f+N,)  
int nFileLength = -1; \t1#5  
try{ 'DVn /3?X  
URL url = new URL(siteInfoBean.getSSiteURL()); MymsDdQ]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); nvf5a-C+q  
httpConnection.setRequestProperty("User-Agent","NetFox"); & ;.rPU  
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5I2 h(Td  
int responseCode=httpConnection.getResponseCode(); '%t$mf!nV  
if(responseCode>=400) %;ED}X  
{ HBR/" m  
processErrorCode(responseCode); gEsD7]o(=  
return -2; //-2 represent access is error 8
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} s=-?kcoJ2d  
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String sHeader; L`K)mCr  
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for(int i=1;;i++) 6Aqv*<1=62  
{ -XL
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); SF*mY=1  
//Utility.log(in.readLine()); KTT
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sHeader=httpConnection.getHeaderFieldKey(i); YToG'#qs  
if(sHeader!=null) d*Su c  
{ 9&=%shOc+x  
if(sHeader.equals("Content-Length")) AZhI~QWo  
{ {'A
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); yN{**?b  
break; jZqa+nG51  
}  *\xRNgEQ  
} ]~dB|WB  
else 9 c9$
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break; xj
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} hz;SDaBA  
} `Zo5!"'  
catch(IOException e){e.printStackTrace ();} jrN 5l1np  
catch(Exception e){e.printStackTrace ();} *!y04'p`<  
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Utility.log(nFileLength); *vRHF1)L  
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return nFileLength; uc!6?+0h  
} ,B/TqPP
  
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//保存下载信息（文件指针位置） ~m=Z>4M  
private void write_nPos() I:=!,4S;  
{
|>U<EtA"  
try{ ;:[P/eg  
output = new DataOutputStream(new FileOutputStream(tmpFile)); {`2 0'  
output.writeInt(nStartPos.length); U= 
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for(int i=0;i<nStartPos.length;i++) Q$.CtECo  
{ 8M!9gvcaO  
// output.writeLong(nPos); $<Gt^3e  
output.writeLong(fileSplitterFetch.nStartPos); EB+4]MsD  
output.writeLong(fileSplitterFetch.nEndPos); u"v$[8  
} "[["naa  
output.close(); '!Va9m*w7  
} B &Z0ZWx  
catch(IOException e){e.printStackTrace ();} n~`jUML2d  
catch(Exception e){e.printStackTrace ();} oSMIWwg7G  
} F'{T[MA  
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//读取保存的下载信息（文件指针位置） ;_< Yzl  
private void read_nPos() 502(CO>  
{ ,:}VbQ:3I  
try{ md{1Jn"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); cqh1,h$sG  
int nCount = input.readInt(); =u9e5n  
nStartPos = new long[nCount]; U/q"F<?.c  
nEndPos = new long[nCount]; X%*BiI  
for(int i=0;i<nStartPos.length;i++) fvTp9T\f3  
{ ~rOvVi&4  
nStartPos = input.readLong(); J^` pE^S  
nEndPos = input.readLong(); )06. dZq\  
} C;ha2UV0H  
input.close(); .ejC#vB{KM  
} t9W*N\  
catch(IOException e){e.printStackTrace ();} 2g)q (  
catch(Exception e){e.printStackTrace ();} p,8:(|(  
} O>X!78]#K  
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private void processErrorCode(int nErrorCode) I %1P:-  
{ :Oj!J&A  
System.err.println("Error Code : " + nErrorCode); Us&~d"n  
} vy5{Vm".4  
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//停止文件下载 'zt}\ Dt  
public void siteStop() o~:({  
{ &{M-<M  
bStop = true; \3U.;}0_X  
for(int i=0;i<nStartPos.length;i++) 9ys[xOh WM  
fileSplitterFetch.splitterStop(); >>-{AR0  
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} sV~|9/r  
} M _Lj
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//负责部分文件的抓取 S
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**FileSplitterFetch.java 2rP!]  
*/ =snJ+yn!  
package NetFox; bb/A}< zD  
G @L`[Wu  
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import java.io.*; P]4u`&  
import java.net.*; z*^vdi0  
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public class FileSplitterFetch extends Thread { A sf]sU..  
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c&L|e$C]  
String sURL; //File URL +{e2TY  
long nStartPos; //File Snippet Start Position G"<} s mB  
long nEndPos; //File Snippet End Position ~|wh/]{b9  
int nThreadID; //Thread's ID ` NvJ  
boolean bDownOver = false; //Downing is over ''EFh&F  
boolean bStop = false; //Stop identical UUgc>  
FileAccessI fileAccessI = null; //File Access interface ;2eZa|M*q  
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bb`DyUy ^+  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException QN~9O^  
{ Z=s]@r  
this.sURL = sURL; #k)J);&ZA  
this.nStartPos = nStart; pvqbk2BO  
this.nEndPos = nEnd; 98l-  
nThreadID = id;
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 7tT L,Nxe  
} .)=j~}\  
[ 3SbWwg  
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public void run() P<xCg  
{ /(ArA=#  
while(nStartPos < nEndPos && !bStop) Mg^3Y'{o  
{ 7}e{&\0=l  
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try{ =G/`r!r*0I  
URL url = new URL(sURL); /{X2:g{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *3Ci4\Ew  
httpConnection.setRequestProperty("User-Agent","NetFox"); pB]+c%\  
String sProperty = "bytes="+nStartPos+"-"; '%A*Z,f  
httpConnection.setRequestProperty("RANGE",sProperty); V)r6bb{^  
Utility.log(sProperty); #>\8m+h 9  
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InputStream input = httpConnection.getInputStream(); )VR/a  
//logResponseHead(httpConnection); IY9##&c3>  
9"k^:}8.  
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byte[] b = new byte[1024]; \>XkK<ye  
int nRead; Z0%Qy+%  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 7(= 09z  
{ K~>ESMZ5  
nStartPos += fileAccessI.write(b,0,nRead); 3/((7O
[  
//if(nThreadID == 1) < G:G/  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ob.=QQQs  
} w!^{Q'/,Q  
-r"h[UV)  
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Utility.log("Thread " + nThreadID + " is over!"); 5PCKBevV  
bDownOver = true; gkDlh{  
//nPos = fileAccessI.write (b,0,nRead); _"%-=^_  
} `~3y[j]kO  
catch(Exception e){e.printStackTrace ();} rwou[QU  
} sv?Lk4_  
} js\|xfDxP  
/F6=iHK(l  
h/n&&J  
//打印回应的头信息 |d8x55dk  
public void logResponseHead(HttpURLConnection con) :s OsG&y  
{ 9i+SU|;j  
for(int i=1;;i++) 2f$6}m'Ad  
{ RBzBR)@5  
String header=con.getHeaderFieldKey(i); U: Q&sq8U  
if(header!=null) VlQaT7Q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); n~NOqvT <  
Utility.log(header+" : "+con.getHeaderField(header)); U#!f^@&AB  
else `[Xff24(eb  
break; A5> ,e|  
} VBK9te,A  
} ${F]N }  
/!Ng"^.e  
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public void splitterStop() H#;-(`F  
{ 1tQl^>r16  
bStop = true; <);Nc1  
} $R[ggH&  
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} u`vOKajpH$  
7 a}qnk%  
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/* dLMKfh/4Q  
**FileAccess.java 2,X~a;+  
*//文件访问(定位，写) eD481r  
package NetFox; L(2KC>GvA  
import java.io.*; %kJ_o*"  
pkL&j<{  
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public class FileAccessI implements Serializable{ ,!s;o6|*y  
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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 8 3wa{m:  
RandomAccessFile oSavedFile; ]%PQ3MT.  
long nPos; (E*eq-8  
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public FileAccessI() throws IOException 
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{ @;we4G5  
this("",0); Sp=6%3fZ]m  
} [l2ds:  
*3A[C-1~.  
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public FileAccessI(String sName,long nPos) throws IOException 67/&.d!  
{ OA_Bz"  
oSavedFile = new RandomAccessFile(sName,"rw"); 5:ZM-kZT  
this.nPos = nPos; '
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oSavedFile.seek(nPos);  Wb/q&o  
} Ty21-0F  
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public synchronized int write(byte[] b,int nStart,int nLen) n%>c4*t  
{ (gv1f  
int n = -1; A@X&dy  
try{ ^$7Lmd.qI  
oSavedFile.write(b,nStart,nLen); ~EVD NnHEr  
n = nLen; a;Q.R  
} q.l"Y#d  
catch(IOException e) Fx.hti  
{ +d0&(b  
e.printStackTrace (); \WnI&nu  
} J<<0U;  
<= xmJx-V  
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return n; ,[l
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} ix<sorR H  
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} JwNG`MGc  
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/* 8v},&rhPQq  
**SiteInfoBean.java rTiW&#  
*/ 4|Dxyb>pS  
package NetFox; a3wTcp "r  
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]}_@!F)  
public class SiteInfoBean { J?WT  
Z^w}: {  
p#9.lFSX  
private String sSiteURL; //Site's URL w a!g/\  
private String sFilePath; //Saved File's Path `
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private String sFileName; //Saved File's Name I-E}D"F;p[  
private int nSplitter; //Count of Splited Downloading File "(6]K}k@  
#-ioLt%  
/hPgOaB  
public SiteInfoBean() V=pg9KR!T  
{//nSplitter的缺省值为5 T>l=0a #  
//default value of nSplitter is 5 W2VH?-Gw  
this("","","",5); xr uQ=Q  
} tK3.HvD  
4}FuoQL  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]wg+zOJu]+  
{ E>tlY&0[$  
sSiteURL= sURL; e~C^*wL  
sFilePath = sPath; 9Z,vpTE
 
sFileName = sName; HL;y5o?  
this.nSplitter = nSpiltter; b]v.jgD  
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} @'.(62v  
M^\#(0^2@  
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public String getSSiteURL() 8}3dwr;-  
{ c7mIwMhl~  
return sSiteURL; n&Q{ [E  
} 3%?01$k  
%(GWR@mfC  
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public void setSSiteURL(String value) ?lJm}0>  
{ KLW#+vZ  
sSiteURL = value; G3HmLz  
} :yN;_bC!b%  
\$
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public String getSFilePath() fRp+-QvE  
{ uXiAN#1  
return sFilePath; <StyO[  
} G992{B  
!/W[6'M#p  
*ip2|2G$  
public void setSFilePath(String value) 8=rD'*  
{ e_Na_l]  
sFilePath = value; EQDsbG0x  
} c"w}<8  
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public String getSFileName() [:
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{ pp$WM\r  
return sFileName; 5;wA7@  
} !424K-nW  
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\|\Dc0p}  
public void setSFileName(String value) " (c#H  
{ hqW4.|&\c  
sFileName = value; V
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} 8<UD#i@:C  
l
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public int getNSplitter() \_pP:e  
{ Tbl~6P  
return nSplitter; aqq7u5O1
r  
} w=.w*?>  
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public void setNSplitter(int nCount) |~b.rKQt[  
{ 1Wd?AyTY,  
nSplitter = nCount; USLG G}R  
} 6/`$Y!.ub  
} H79XP.TtE  
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:_;9&[H9ha  
/* +cQGX5 K  
**Utility.java iHoQNog-!  
*/ hsIC5@s3  
package NetFox; X~ n=U4s}O  
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public class Utility { <[O8{9j  
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public Utility() 7`;55Se  
{ ~kUdHne(  
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} aIV(&7KT4  
tZlz0BY!  
//线程睡眠 *RugVH4  
public static void sleep(int nSecond) M)td%<_  
{ T|o[! @:,  
try{ +b_g,RNs!  
Thread.sleep(nSecond); 7=yC*]BH-=  
} @/i;/$\
 
catch(Exception e) %N 8/g]`7  
{ Rg3 Lo ?  
e.printStackTrace (); o<@b]ukl&  
} #L[-WC]1y  
} 0PIiG-o9  
f`w$KVZ1!w  
//日志 1"J\iwN3  
public static void log(String sMsg) aa:Oh^AJy  
{ `2X~3im  
System.err.println(sMsg); c e`3&  
} Mf)0Y~_:R#  
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K7 >Z)21  
public static void log(int sMsg) +JoE[;  
{ fx@Hd!nO~"  
System.err.println(sMsg); "L^Klk?Vn  
} Ipo?>To  
} V?U->0>Z4  
"Sp+Q&2U  
| k"?I  
/* d&K2\n  
**TestMethod.java )SG+9!AbMZ  
*/ @
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package NetFox; b~?FV>gl  
m
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:A%|'HxH3  
public class TestMethod { G0p|44_~t  
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public TestMethod() k$`~,LJp  
{ ///xx/weblogic60b2_win.exe '51DdT
U  
try{ hhjT{>je  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Dohq@+] O  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 8 1;QF_C  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8z&7wO  
fileFetch.start(); b e[KNrO  
} ~_C[~-  
catch(Exception e){e.printStackTrace ();} S#+Dfa`8X  
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o.yuz+  
} fY3^L"R  
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public static void main(String[] args) mY9^W2:  
{ t,$4J6  
new TestMethod(); c>+l3&`  
} .nCF`5T!  
} 7\*_/[
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