http断点续传简单实现（java)

/* poJ7q (  
**SiteFileFetch.java >q W_%  
*/ c6 O1Z\M@\  
package NetFox; kmfz=
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import java.io.*; J<K-Yeph  
import java.net.*; <{$0mUn;s|  
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public class SiteFileFetch extends Thread { !~X[qT  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ahezDDR-.i  
long[] nStartPos; //开始位置 e,j2#wjor  
long[] nEndPos; //结束位置 5R^e  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )ro3yq4??  
long nFileLength; //文件长度 ~W?F.  
boolean bFirst = true; //是否第一次取文件 o}EipTL  
boolean bStop = false; //停止标志 >%qk2h>  
File tmpFile; //文件下载的临时信息 "9mVBa|Q  
DataOutputStream output; //输出到文件的输出流 DeqTr:  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） +7yirp~`K  
public SiteFileFetch(SiteInfoBean bean) throws IOException y2"PKBK\_  
{ Xx.4K>j+j  
siteInfoBean = bean; :exgdm;N  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); c?@
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); +rT%C&ze  
if(tmpFile.exists ()) 82w;}(!  
{ lr>:S  
bFirst = false; _hM #*?}v  
read_nPos(); wUUDq?!k\  
} $bf&ct*$h  
else )C?bb$ G  
{ VD=}GY33=  
nStartPos = new long[bean.getNSplitter()]; z"cF\F  
nEndPos = new long[bean.getNSplitter()]; R$[nYw  
} XwI~ 0  
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} Cxn<#Kf\-<  
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public void run() ;3\oU$'  
{ E;$;
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//获得文件长度 +sN'Y/-  
//分割文件 aT9+] Ig  
//实例FileSplitterFetch qN5 ru2  
//启动FileSplitterFetch线程 ^]x%z*6  
//等待子线程返回 <Mdyz!  
try{ i}fAjS:W  
if(bFirst) t r)[6o#  
{ (#|CL/&  
nFileLength = getFileSize(); f9+J}  
if(nFileLength == -1) M4%u~Z:4h+  
{ B8XW+U  
System.err.println("File Length is not known!"); A`|Z2  
} s& INcjC  
else if(nFileLength == -2) X#625h  
{ " Bz\<e&u  
System.err.println("File is not access!"); u%TZ),ny-  
} <F>^ffwGH-  
else bn$('  
{ z
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for(int i=0;i<nStartPos.length;i++) n*'i{P]  
{ ]4{ )VXod  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Y]zy=8q  
} @D?KS;#  
for(int i=0;i<nEndPos.length-1;i++) c"nowbf  
{ h
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nEndPos = nStartPos[i+1]; |2i=oX(r|  
} 0_!')+  
nEndPos[nEndPos.length-1] = nFileLength; 2sezZeMV  
} {6_M$"e.  
} 7WEh'(`  
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//启动子线程 zm
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ~}lYp^~:J  
for(int i=0;i<nStartPos.length;i++) ,M4G_U[  
{ lpjeEawo4  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -<g&U*/E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), i6S5 4&^!  
nStartPos,nEndPos,i); n!Dr:$  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \wJ2>Q  
fileSplitterFetch.start(); iMT[sb  
} "aU) [  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fwkklg^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); >yZe1CP  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #9(0.!v  
nEndPos = " + nFileLength); @3^D[  
// fileSplitterFetch[nPos.length-1].start(); \ oY/hT_  
~wtK(U  
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//等待子线程结束 uwL^Tq}Yh  
//int count = 0; KF4D)NM|  
//是否结束while循环 ax.;IU  
boolean breakWhile = false; xj ?#
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6#J>b[Q  
while(!bStop) yt5Sy  
{ N$!aP/b  
write_nPos(); *
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Utility.sleep(500); 1Fg*--8[r  
breakWhile = true; "jUM}@q5  
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for(int i=0;i<nStartPos.length;i++) 6>yfm4o  
{ ~nVO%IxM4J  
if(!fileSplitterFetch.bDownOver) azs lNL  
{ a-cLy*W,~  
breakWhile = false; Lhts4D/V7  
break; bwC~  
} &H4Y`xV^=  
} s|`ZV^R  
if(breakWhile) yd}1Mx  
break; =O1py_m  
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//count++; bQvhBa?  
//if(count>4) D<QE?:#  
// siteStop(); <dD)>Y.  
} %W(/W9B$/F  
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System.err.println("文件下载结束！"); {^T_m)|n  
} j;MQ_?"iN  
catch(Exception e){e.printStackTrace ();} L0Ycf|[s,  
} iwXMe(k  
*el~sor;S  
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//获得文件长度 NimW=X;c  
public long getFileSize() N^TE ;BM  
{ @Y&UP  
int nFileLength = -1; XkEJ_;:  
try{ ^vY[d]R _\  
URL url = new URL(siteInfoBean.getSSiteURL()); +%~/~1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 61@;3yV  
httpConnection.setRequestProperty("User-Agent","NetFox"); S;8gX1Uf  
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int responseCode=httpConnection.getResponseCode(); 4Zn"K}q  
if(responseCode>=400) Mb^E  
{ ,J4rKGG  
processErrorCode(responseCode); ubQbEv{(,  
return -2; //-2 represent access is error WAUgbImc{  
} Xl %ax!/  
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String sHeader; '@{Mq%`  
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for(int i=1;;i++) #]kO/Mr  
{ RYyM;<9F  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); p.|M:C\xL  
//Utility.log(in.readLine()); q2e=(]rKE{  
sHeader=httpConnection.getHeaderFieldKey(i); 9 S4bg7  
if(sHeader!=null) $X_A74(  
{ 2X,`t%o  
if(sHeader.equals("Content-Length")) KNG7$icG  
{ NVX@1}  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); IZs NMY  
break; T^DJ/uhd  
} m#,AD,s  
} E;bv;RUio  
else u Wxl\+_i  
break; wj2z?0}o  
} ;i,3KJ[L  
} O%)Wo?)HM  
catch(IOException e){e.printStackTrace ();} ["1Iz{  
catch(Exception e){e.printStackTrace ();} m>9j dsqB  
9SQcChG~j  
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Utility.log(nFileLength); P^57a?[`  
' 4.T1i,  
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return nFileLength; ?p'DgL{  
} w(oi6kg  
})yB2Q0  
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//保存下载信息（文件指针位置） V0G"Z6  
private void write_nPos() ( u^`3=%n  
{ x(+H1D\W  
try{ bV&"
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output = new DataOutputStream(new FileOutputStream(tmpFile)); 6qd?&.=r  
output.writeInt(nStartPos.length); 'w8p[h (,  
for(int i=0;i<nStartPos.length;i++) VCX^D)[-  
{ Y[rRz6.*(  
// output.writeLong(nPos); f;=<$Y>i  
output.writeLong(fileSplitterFetch.nStartPos); ,92wW&2  
output.writeLong(fileSplitterFetch.nEndPos); 
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} yi;pn Z  
output.close(); *6aIDFNl  
} (b8ZADI*  
catch(IOException e){e.printStackTrace ();} :pdl2#5H^  
catch(Exception e){e.printStackTrace ();} 85_Qb2<'r  
} 0fog/c#q(  
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>zo_}A!  
//读取保存的下载信息（文件指针位置） Z</57w#-7  
private void read_nPos() wE3fKG.  
{ LUzn7FZk  
try{ hjq@.5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *t300`x
  
int nCount = input.readInt(); 0=k  
nStartPos = new long[nCount]; 6E{(_i  
nEndPos = new long[nCount]; 2&zklXuo:  
for(int i=0;i<nStartPos.length;i++) 9/JBn
 
{ V~sfR^FQ'  
nStartPos = input.readLong(); ]@uuB\u  
nEndPos = input.readLong(); C@3UsD\s(  
} mRIBE9K+&  
input.close(); im@QJ:  
} 97k}{tG  
catch(IOException e){e.printStackTrace ();} X?.tj Z,  
catch(Exception e){e.printStackTrace ();} w/e?K4  
} x c|1?AFj  
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`>&K=C?  
private void processErrorCode(int nErrorCode) 8`z  
{ DJb9] ,=a  
System.err.println("Error Code : " + nErrorCode); snYyxi

  
} [nf5<  
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//停止文件下载 xEg@Y"NQ  
public void siteStop() t 7D~JAx6  
{ .q<5O
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bStop = true; SQJ+C%   
for(int i=0;i<nStartPos.length;i++) Mq='|0,  
fileSplitterFetch.splitterStop(); dVSQG947i:  
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} V8rS~'{\  
} =~TPrO^  
//负责部分文件的抓取 ?&=JGk^eJ  
**FileSplitterFetch.java `<-/e%8  
*/ <k 'zz:[c!  
package NetFox; 4BZ7R,m#.  
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import java.io.*; Nw '$r  
import java.net.*; owx0J,,G  
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public class FileSplitterFetch extends Thread { ZgfhNI\
 
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String sURL; //File URL [Z^26/5a  
long nStartPos; //File Snippet Start Position 7Vuf4Z5  
long nEndPos; //File Snippet End Position ~gaWZQXyu  
int nThreadID; //Thread's ID nrR2U`  
boolean bDownOver = false; //Downing is over 6mqp`x`  
boolean bStop = false; //Stop identical K >Q6  
FileAccessI fileAccessI = null; //File Access interface OAaLCpRp  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <cxe   
{ <cO `jK  
this.sURL = sURL; cRE6/qrXGg  
this.nStartPos = nStart;  kGAB'  
this.nEndPos = nEnd; -O\fy!  
nThreadID = id; b&6lu4D  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 R$`%<Y3)  
} xDNXI01o  
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<{j;']V;  
public void run() ,/&|:PkS  
{ JNo[<SZb  
while(nStartPos < nEndPos && !bStop) ^<_rE-k  
{ CjEzsjqe<I  
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try{ UW1i%u k  
URL url = new URL(sURL); P`avn  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -f*5lk
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httpConnection.setRequestProperty("User-Agent","NetFox"); |;\pAZ2  
String sProperty = "bytes="+nStartPos+"-"; y&/bp<Z  
httpConnection.setRequestProperty("RANGE",sProperty); [hV}$0#E[O  
Utility.log(sProperty); ]WK~`-3C^  
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InputStream input = httpConnection.getInputStream(); hcM9Sx"!  
//logResponseHead(httpConnection); B4*uS (  
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byte[] b = new byte[1024]; {9* l  
int nRead; T-h[$fxR_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) +F.@n_}p-I  
{ jrpki<D  
nStartPos += fileAccessI.write(b,0,nRead); 8n["/5,  
//if(nThreadID == 1) ^\[c][fo  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); N,UUM|?9_  
} m6'9Id-:L  
b7'l3mQjk  
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Utility.log("Thread " + nThreadID + " is over!"); SYh>FF"  
bDownOver = true; @urZ  
//nPos = fileAccessI.write (b,0,nRead); 
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} SAdo9m'  
catch(Exception e){e.printStackTrace ();} -q8l"i>h=  
} ^j2ve's:  
} 9{e/ V)  
o'Fyo4Qd  
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//打印回应的头信息 l%xTF@4e  
public void logResponseHead(HttpURLConnection con) ?op;#/Q(  
{ \4>w17qng  
for(int i=1;;i++) 1CR\!?  
{ <Mu T7x-  
String header=con.getHeaderFieldKey(i); xel|,|*Yq  
if(header!=null) 5V~vND* s  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 'h^Ya?g  
Utility.log(header+" : "+con.getHeaderField(header)); *3
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else Kz
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break; l-Ha*>gX[j  
} UFLx'VXd  
} l*{Bz5hc  
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/ !y~Q|<|=  
public void splitterStop() 6=Wevb5YJ  
{ JH u>\{8V  
bStop = true; e"*1l>g  
} 'nq~1 >i  
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} ;Qi!~VsP;  
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/* sSc~q+xz  
**FileAccess.java 'p78^4'PL  
*//文件访问(定位，写) )Gk?x$pY@  
package NetFox; vexF|'!}0#  
import java.io.*; EZzR"W/  
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public class FileAccessI implements Serializable{ 8TG
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UG_PrZd  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 D?UURURf  
RandomAccessFile oSavedFile; W /*?y&  
long nPos; 2(x| %  
X @pm!c#  
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public FileAccessI() throws IOException t: oQHhO?  
{ Ujlbcv6+  
this("",0); 9HPmJ`b  
} "q1S.3V;  
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public FileAccessI(String sName,long nPos) throws IOException wt;`_}g  
{ pQ!lY  
oSavedFile = new RandomAccessFile(sName,"rw"); Q2)(tB= )  
this.nPos = nPos; $06('
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oSavedFile.seek(nPos); 'U*#71S  
} %Ofw"W  
.t8hTlV?<B  
/I1n${{5  
public synchronized int write(byte[] b,int nStart,int nLen) 'rS\9T  
{ zb4{nzX=  
int n = -1; j%D{z5,nKm  
try{ iq?T&44&  
oSavedFile.write(b,nStart,nLen); ~wF3$H.@;  
n = nLen; |z"$^|@d?  
} [b&V^41W  
catch(IOException e) 4mKH |\g  
{ SSTn|  
e.printStackTrace (); *M*WjEOA  
} xWqV~NnE  
:475FPy]  
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return n; Aqz $WTHW+  
} $}0!dR2  
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} T31F8K3x  
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/* 3 {hUp81>  
**SiteInfoBean.java Fw{68ggk  
*/ 8SLE*c^8  
package NetFox; n*' :,m  
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public class SiteInfoBean { UjLq[,_!  
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private String sSiteURL; //Site's URL K"|~D0Qgo  
private String sFilePath; //Saved File's Path #_`p 0wY  
private String sFileName; //Saved File's Name 
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private int nSplitter; //Count of Splited Downloading File :VWN/m  
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public SiteInfoBean() 3TLym&  
{//nSplitter的缺省值为5 J]zhwM  
//default value of nSplitter is 5 @o*~\E<T  
this("","","",5); M(:bM1AD`u  
} 9Iq<*\V 4  
+'iqGg-  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) oM^vJ3  
{ F
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sSiteURL= sURL; -!mtL
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sFilePath = sPath; Gc*=n*@^K  
sFileName = sName; DfU= i'R  
this.nSplitter = nSpiltter; !fd>wvJ,:  
64'QTF{D  
=
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} bA2[=6  
v _:KqdmO]  
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public String getSSiteURL() ;&f(7 Q+T_  
{ -5]lHw}  
return sSiteURL; %.wR@
9?  
} BzH0"xq^  
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public void setSSiteURL(String value) iR PE0  
{ W1Fhx`  
sSiteURL = value; y`5 ?  
} 2~7*jA+Ab  
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public String getSFilePath() [\ Sd*-  
{ e-UWbn'~  
return sFilePath; m8x?`Gw~jw  
} %K8YZc(&  
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public void setSFilePath(String value) q4Bw5
~n  
{ *?C8,;=2r  
sFilePath = value; 4M|C>My  
} {06ClI  
8.^`~ta  
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public String getSFileName() Zn40NKYc  
{ t2.jg?`k
 
return sFileName; Z+EZ</'(a  
}
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public void setSFileName(String value) Wd(|w8J{a  
{ =jpRv<
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sFileName = value; /X0<2&v  
} bA$ElKT  
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public int getNSplitter()  P s|[  
{ H8B.c%_|U  
return nSplitter; 'qo(GGC M  
} zL50|U0H  
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public void setNSplitter(int nCount) `WxGU  
{ tQyQ+
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nSplitter = nCount; 8'fF{C  
} ygm6(+  
} s(s_v ?k  
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*!Gb_!98  
/* cFJZ|Ld  
**Utility.java p<Tg}fg  
*/ 'Cz]p~oF  
package NetFox; eYjF"Aq
 
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public class Utility { sT<h+[2d  
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public Utility() -sle7k  
{ zH~g5xgh  
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} fHI@' '0  
=M4wP3V/  
//线程睡眠 K&dc< 4DC  
public static void sleep(int nSecond) u8<Fk !  
{ &@2`_%QtA  
try{ +, rm  
Thread.sleep(nSecond); 1. Q"<[M  
} RJN LcIm  
catch(Exception e) u+jx3aP:  
{ ~+RrL,t#  
e.printStackTrace (); xB
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} t)(>E'X x  
} s <$*A;t  
qe0ZM-C_  
//日志 '=(yh{W  
public static void log(String sMsg) )D]LPCd[  
{ T0\[": A  
System.err.println(sMsg); #\z"k<{*  
} &mA{_|>  
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public static void log(int sMsg) !+
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{ ry* 9  
System.err.println(sMsg); q'biTn]2  
} 1gYvp9Ma  
} tf9a- s  
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/* 1py>[II@  
**TestMethod.java %.{xo.`a[  
*/ |l?*' =  
package NetFox; :{Iv ]d  
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public class TestMethod { o
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#N\<(SD/  
public TestMethod() #q?:Act  
{ ///xx/weblogic60b2_win.exe T=pKen/  
try{ 2&F  H8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); uv7tbI"r  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ).$kp
2IN  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 2QIo|$  
fileFetch.start(); <<1_rRL]  
}
"fd'~e$S#  
catch(Exception e){e.printStackTrace ();} kAoh#8=  
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} \3j4=K'nE  
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_eaK:EW  
public static void main(String[] args) 3HX-lg`0  
{ hXn@vK6  
new TestMethod(); T@N)BfkB  
} 6uWPIM;  
} #j"N5e}U  
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