http断点续传简单实现（java)

/* =|P &G~]  
**SiteFileFetch.java lcZ.}   
*/ DO80HS3ZD  
package NetFox; =|agW.l  
import java.io.*; #_35bg4h{  
import java.net.*; (|^m9v0:  
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public class SiteFileFetch extends Thread { 0mSP  
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SiteInfoBean siteInfoBean = null; //文件信息Bean S/5QK(XLC)  
long[] nStartPos; //开始位置 0h@FHw2d  
long[] nEndPos; //结束位置 z;S-Q,  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 3>1^$0iq  
long nFileLength; //文件长度 nf /*n  
boolean bFirst = true; //是否第一次取文件 p?Azn>qBa  
boolean bStop = false; //停止标志 *7Q6b 4~"  
File tmpFile; //文件下载的临时信息 EB*sd S  
DataOutputStream output; //输出到文件的输出流 iwJ_~  
2HFn\kjj.s  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） {o24A:M  
public SiteFileFetch(SiteInfoBean bean) throws IOException ^-Od*
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{ qazA,|L!  
siteInfoBean = bean; +\Vm t[v  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); RHC ZP  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 3{3@>8{w  
if(tmpFile.exists ()) gY~r{  
{ b4_0XmL  
bFirst = false; |[>@Kk4  
read_nPos(); \
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} [Iks8ZWr_  
else O6;"cUv  
{ tON>wmN  
nStartPos = new long[bean.getNSplitter()]; pIlEoG=[_  
nEndPos = new long[bean.getNSplitter()];
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} O{X~,Em=q  
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} C[^V\?3ly:  
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2 kDsIEA  
public void run() Z0Z6aZeb  
{ Xi&J%N'  
//获得文件长度 ?mg@zq8  
//分割文件 0\%g@j-aD  
//实例FileSplitterFetch &-ropY  
//启动FileSplitterFetch线程 |ri)-Bk ,  
//等待子线程返回 9wWBE<}>u  
try{ [%.v;+L  
if(bFirst) 3gi)QCsk  
{ MoIh=rw  
nFileLength = getFileSize(); :skR6J  
if(nFileLength == -1) ~skp}g]  
{ v=N?(6T  
System.err.println("File Length is not known!"); 3xChik{  
} =j,WQ66r3  
else if(nFileLength == -2) Nwi|>'\C  
{ yn62NyK  
System.err.println("File is not access!"); &P?2H66s  
} j<<d A[X  
else FO2e7p^Q  
{ PE%$g\#?  
for(int i=0;i<nStartPos.length;i++) 1)(>'pY  
{ I/dy^5@F  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); !ZBtXt#P  
} [C "\]LiX  
for(int i=0;i<nEndPos.length-1;i++) 3$\k=q3`#  
{ 9"P|Csj  
nEndPos = nStartPos[i+1]; bx3Q$|M?  
} X06Lr!-%  
nEndPos[nEndPos.length-1] = nFileLength; I_J&>}V'  
} ]Ox5F@  
} BR2Gb~#T  
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//启动子线程 r`O Yq  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0*$w(*  
for(int i=0;i<nStartPos.length;i++) ?%s>a8w  
{ x}] 56f  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), LIZB!S@V\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3 t,_{9  
nStartPos,nEndPos,i); ^dQ{vL@9b9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); REUxXaN>Z  
fileSplitterFetch.start(); )%7P?^>  
} 0xB2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Qz~uD'Rs/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); i>F=XE  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3P cVE\GN  
nEndPos = " + nFileLength); }|P3(*S  
// fileSplitterFetch[nPos.length-1].start(); @UD:zUT)F  
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//等待子线程结束 >@YefN
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//int count = 0; tEhg',2t(  
//是否结束while循环 qLN\%}69/  
boolean breakWhile = false; A]z*#+Sl  
&|hK79D  
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while(!bStop) 2c9?,Le/;  
{ ]b4WfIu  
write_nPos(); ?{ir$M  
Utility.sleep(500); 4%(Ji  
breakWhile = true; <)VgGjZ-H  
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for(int i=0;i<nStartPos.length;i++) q-F K=r 5  
{ y0* rY  
if(!fileSplitterFetch.bDownOver) d!,t_jM0  
{ P
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breakWhile = false; nr!N%Hi  
break; g52a vG  
} ^#/FkEt7bp  
} %MHb  
if(breakWhile) v4P"|vZ$&  
break; zCx4DN`  
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//count++; (j: ptQ2$  
//if(count>4) ^jdU4  
// siteStop(); ag=d6q  
} t'qYM5  
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?8b19DMK6  
System.err.println("文件下载结束！"); lPTx] =G  
} yeo&Qz2vU  
catch(Exception e){e.printStackTrace ();} oo5=5s6 3}  
} c`a(  
*r7vDc  
/R)wM#&  
//获得文件长度 >[}oH2oi  
public long getFileSize() YDt+1Kw}D  
{ y>^a~}Z
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int nFileLength = -1; G95,J/w  
try{ 0I&k_7_  
URL url = new URL(siteInfoBean.getSSiteURL()); OmYVJt_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V2MOD{Maat  
httpConnection.setRequestProperty("User-Agent","NetFox"); )-C3z  
0'QWa{dS\  
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int responseCode=httpConnection.getResponseCode(); qL(Q1O!  
if(responseCode>=400) RZ".?  
{ zZ5:)YiW-  
processErrorCode(responseCode); }lJ;|kx$  
return -2; //-2 represent access is error hp\&g2_S0W  
} YGp+[|'  
tK#R`AQ  
}U_ '7_JT  
String sHeader; UX 1 )((  
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for(int i=1;;i++) K2   
{ 'D\Q$q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); )Fw/Cu  
//Utility.log(in.readLine()); E~'mxx~i  
sHeader=httpConnection.getHeaderFieldKey(i); x(_[D08/TT  
if(sHeader!=null) *b~6 BM$  
{ p?@ %/!S  
if(sHeader.equals("Content-Length")) @mp`C}x"0&  
{ xmW~R*^  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); nwRltK  
break; 7e/+C{3v  
} 6cQgp]%  
}  4M'>oa  
else gq?:n.;TY  
break; U|(+-R8Z  
} d0cL9&~qW  
} EY}:aur  
catch(IOException e){e.printStackTrace ();} }aCa2%  
catch(Exception e){e.printStackTrace ();} #YUaM<O  
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Utility.log(nFileLength); gv#\}/->4  
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return nFileLength; ~E<2gMKjO  
} d:H'[l.F%  
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//保存下载信息（文件指针位置） .
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private void write_nPos() 6_LeP9s )  
{ bS.w<V Ew  
try{ ZzT
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output = new DataOutputStream(new FileOutputStream(tmpFile)); niVR!l  
output.writeInt(nStartPos.length); !xM5 A[f  
for(int i=0;i<nStartPos.length;i++) KWTV!Wxb=K  
{ 5=dL`  
// output.writeLong(nPos); B@,9Cx564  
output.writeLong(fileSplitterFetch.nStartPos); k$EVr([  
output.writeLong(fileSplitterFetch.nEndPos); K|& f5w  
} Z6jEj9?O  
output.close(); Mf}M/Fh  
} wBPo{  
catch(IOException e){e.printStackTrace ();} 8~sP{V%  
catch(Exception e){e.printStackTrace ();} )8Va%{j  
} ~6vz2DuB=  
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//读取保存的下载信息（文件指针位置） "L~(%Nx3  
private void read_nPos() uOxHa>h  
{ b}J%4Lx%m  
try{ }Q7y tE  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 4#U}bN  
int nCount = input.readInt(); 3Ob.OwA  
nStartPos = new long[nCount]; R[WiW RfD  
nEndPos = new long[nCount]; |"H 2'L$  
for(int i=0;i<nStartPos.length;i++) 2wf&jGHs  
{ 2[E wN!IZ  
nStartPos = input.readLong(); <v"o+  
nEndPos = input.readLong(); !e$gp(4  
} 3} A$+PX  
input.close(); / )0hsQs  
} +)]YvZ6%[,  
catch(IOException e){e.printStackTrace ();} $YYWpeW '  
catch(Exception e){e.printStackTrace ();} :Pud%}'  
} c:R?da  
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private void processErrorCode(int nErrorCode) |<%!9Z  
{ Bqx5N"  
System.err.println("Error Code : " + nErrorCode); %!|w(Povq  
} }
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//停止文件下载 S_}`'Z )  
public void siteStop() Cj5mM[:s  
{ Lu.zc='\  
bStop = true; UHBXq;?&q  
for(int i=0;i<nStartPos.length;i++) >rG>Bz^Pu  
fileSplitterFetch.splitterStop(); Io6/Fv>!  
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} 18g_v"6o  
} Hl*v
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//负责部分文件的抓取 Cu"Cpt[  
**FileSplitterFetch.java .nV2n@SR  
*/ >J"INI  
package NetFox; 5/H,UL  
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import java.io.*; 3"fDFR  
import java.net.*; A_9WSXR  
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public class FileSplitterFetch extends Thread { xm'9n?  
@sXFu[!U  
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String sURL; //File URL j;x()iZ<  
long nStartPos; //File Snippet Start Position ez4!5&TzRm  
long nEndPos; //File Snippet End Position L"_XWno  
int nThreadID; //Thread's ID #h5:b`fDF  
boolean bDownOver = false; //Downing is over A|A~$v("R  
boolean bStop = false; //Stop identical HDVimoOq  
FileAccessI fileAccessI = null; //File Access interface bMH~vR  
{@Wv@H+4  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?vXgHDs^T  
{ wjarQog5Y  
this.sURL = sURL; =u~nLL  
this.nStartPos = nStart; p6M9uu  
this.nEndPos = nEnd; q*!R4yE;C  
nThreadID = id; 'H1~Zhv  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %1z;l.c  
} MqmQ52HR  
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public void run() b UG,~\Z  
{ 0RR|!zEu  
while(nStartPos < nEndPos && !bStop) |OQ]F  
{ 8f@}-  
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try{ fv+]iK<{  
URL url = new URL(sURL); \ovs[&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); g?j)p y  
httpConnection.setRequestProperty("User-Agent","NetFox"); FaHOutP  
String sProperty = "bytes="+nStartPos+"-"; 5Rqdo\vE  
httpConnection.setRequestProperty("RANGE",sProperty); /Vlc8G  
Utility.log(sProperty); "k
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InputStream input = httpConnection.getInputStream(); ;Iu _*U9)  
//logResponseHead(httpConnection); ]4:QqdV  
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byte[] b = new byte[1024]; dwj?;  
int nRead; rYUIFPN  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) $H:!3-/  
{ :;?$5h*|`  
nStartPos += fileAccessI.write(b,0,nRead); 2a d|v]  
//if(nThreadID == 1) +NlnK6T/  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F>;Wbk&[|  
} U)}]Z@I-  
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Utility.log("Thread " + nThreadID + " is over!"); A#U! KX  
bDownOver = true; E^8|xT'h6  
//nPos = fileAccessI.write (b,0,nRead); xd Z$|{,  
} Z)!8a$M~  
catch(Exception e){e.printStackTrace ();} i'Y8-})  
} %ms%0%  
} U-|]A\`)I  
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;
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//打印回应的头信息 R'BB-  
public void logResponseHead(HttpURLConnection con) :e<jD_.X  
{ MU<(O}  
for(int i=1;;i++) 6?Ncgj &@  
{ Pz)lq2Zm9  
String header=con.getHeaderFieldKey(i); h nydH-;cz  
if(header!=null) g*k)
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); [ATJ! O  
Utility.log(header+" : "+con.getHeaderField(header)); /t5)&  
else "Eh=@?]S_  
break; \JLGw1F  
} !'f7;%7s  
} |)x7qy`  
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public void splitterStop() RhWQ:l]  
{ ==Gc%  
bStop = true; _p$/.~Xo9  
} Yf0 
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} +pd,gG?dW  
x $uhkP  

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/* A?R`~*Q5  
**FileAccess.java D4
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*//文件访问(定位，写) b6k`R4S3  
package NetFox; )uqzu%T  
import java.io.*; .*zN@y3  
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public class FileAccessI implements Serializable{ i/:L^SQAq  
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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 20Zxv!  
RandomAccessFile oSavedFile; 2A_1E\  
long nPos; 9f~qD&~  
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public FileAccessI() throws IOException zgD?e?yPO  
{ e=;A3S  
this("",0); Wf c/?{  
} B=A!hXNa  
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public FileAccessI(String sName,long nPos) throws IOException l";Yw]:^  
{ f' A$':Y  
oSavedFile = new RandomAccessFile(sName,"rw"); fHiL%]z  
this.nPos = nPos; ElO|6kOBYG  
oSavedFile.seek(nPos); ?G`m;S  
} _E'?U  
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public synchronized int write(byte[] b,int nStart,int nLen) 8
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{ /2
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int n = -1; M?l v  
try{ bjVk9XvH6  
oSavedFile.write(b,nStart,nLen); @a9.s  
n = nLen; UL[,A+X8D  
} 4cQP+n  
catch(IOException e) KV0*dB;  
{ k^ <]:B  
e.printStackTrace (); !wp1Df[  
} =$OGHc  
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return n; 7O1MC 8{  
} '$FF/|{  

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} } =OE.cf@  
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/* ;JxL>K(  
**SiteInfoBean.java "_/ih1z]
 
*/ fkI 5~Y|  
package NetFox; ^J]&($-  
}MaY:PMA  
!hVbx#bXl  
public class SiteInfoBean { 4iAF<|6s  
3\W/VBJJ  
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private String sSiteURL; //Site's URL "Z&.m..gc  
private String sFilePath; //Saved File's Path biHacm  
private String sFileName; //Saved File's Name 4Y(@ KUb  
private int nSplitter; //Count of Splited Downloading File 1.14tS-}[4  
}AS?q?4?  
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public SiteInfoBean() xhP~]akHN7  
{//nSplitter的缺省值为5 X['9;1Xr  
//default value of nSplitter is 5 '=0}2sF>  
this("","","",5); ZWkRoJXNi  
} (;#c[eKy  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) d?7?tL2  
{ K/W=r  
sSiteURL= sURL; $Ivjcs:  
sFilePath = sPath; ;M?)-dpZ  
sFileName = sName; u1/>)_U  
this.nSplitter = nSpiltter; G(t:s5:  
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nL 5tHz:e  
} -PV1x1|
 
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public String getSSiteURL() ZR!8hw8  
{ os5$(  
return sSiteURL; [NSslVr  
} WJq>%<#  
G[KjK$.Ts?  
2iNLm6"  
public void setSSiteURL(String value) W{;Qi&^ca  
{ (p2`ofj  
sSiteURL = value; :u4|6?  
} -m@c{&r  
 Qxz[  
h  /  
public String getSFilePath() LSta]81B4L  
{ $!O@Z8B  
return sFilePath; ?I?G+(bq  
} pX%:XpC!h  
n%3!)/$  
| In{5Ek  
public void setSFilePath(String value) l\Ozy  
{ egu{}5  
sFilePath = value; OD)X7PU  
} _^FC9  
S
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?("O.<
 
public String getSFileName() ^BF}wQb:j  
{ &ZD@-"@  
return sFileName; 8xB-cE  
} u[)X="-e#  
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public void setSFileName(String value) %DSr@IX  
{ hi,=" /9
 
sFileName = value; &>qUT]w  
} /MtmO$.  
m]?Z_*1  
cb_C2+%8NA  
public int getNSplitter() O=A R`r#u  
{ <ww D*t  
return nSplitter; :[<Y#EX.  
} 4.,EKw3  
e_b,{l#  
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public void setNSplitter(int nCount) [r`KoHwdm  
{ Ke4oLF2
 
nSplitter = nCount; wNi%u{T  
} "-f]d~P>  
} |!(8c>]Bo  
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/* M!6Fnj  
**Utility.java _4>DuklH,  
*/ k^oSG1F  
package NetFox; eP2Q2C8g  
!EIH"`>!  
r $S9/  
public class Utility { IGTO|sT"  
h.tj8O1  

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public Utility() )#AYb   
{ $+PioSq  
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} Q%O9DCi  
lB27Z}  
//线程睡眠 Mzg'$]N  
public static void sleep(int nSecond) |6d:k~p  
{ @zS/J,:v}  
try{ qtOuA  
Thread.sleep(nSecond); 4AhFE@  
} oRd{?I&NY  
catch(Exception e) +_:p8, 5o  
{ |!K&h(J|  
e.printStackTrace (); |6NvByc,  
} :vi %7  
} ]/!*^;cY(  
05ZYOs}  
//日志 HV!P]82Pa  
public static void log(String sMsg) Jha*BaD~N  
{ U+VJiz<!  
System.err.println(sMsg); <@`K^g;W  
} ]}SV%*{%  
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=3,<(F5Y[  
public static void log(int sMsg) pjO  
{ 5 n4/}s  
System.err.println(sMsg); NH/jkt&F[  
} mV]~}7*Y;  
} l&Q@+xb>  
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/* C|
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**TestMethod.java 'q9Ejig  
*/ ]Q^8 9?  
package NetFox; '_g&!
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lU|ltnU  
public class TestMethod { ?Zv5iI  
akw:3+`  
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public TestMethod() Ge$&k  
{ ///xx/weblogic60b2_win.exe _)-2h[  
try{ fo}@B&=4  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); N0fE*xo  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); j+<!4 0#  
SiteFileFetch fileFetch = new SiteFileFetch(bean); RW>F %P  
fileFetch.start(); )P1NX"A  
} >y+j!)\  
catch(Exception e){e.printStackTrace ();} Kc9)Lzu+  
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7({.kD6  
} \l6mXIn=>  
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public static void main(String[] args) /9y'UKl7[  
{ :+DAzjwO<  
new TestMethod(); [0+5 Gx  
} 43J8PMY  
} '\m\$ {  
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