http断点续传简单实现（java)

/* \w`Il"}V  
**SiteFileFetch.java R4qS,2E  
*/ cvc.-7IO  
package NetFox; 'MC)%N,  
import java.io.*; j[=f;&1  
import java.net.*; q 2=^l  
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public class SiteFileFetch extends Thread { UkeW
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SiteInfoBean siteInfoBean = null; //文件信息Bean c.d*DM}W  
long[] nStartPos; //开始位置 \WZ00Y,*  
long[] nEndPos; //结束位置 Be}Cj(C  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 HK ;C*;vC%  
long nFileLength; //文件长度 >r{,$)H0  
boolean bFirst = true; //是否第一次取文件 1_<'S34  
boolean bStop = false; //停止标志 zzPgLE55  
File tmpFile; //文件下载的临时信息 ..n-&(c32  
DataOutputStream output; //输出到文件的输出流 N-vr_4{g  
#>!!#e!*  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） EV~_-YC   
public SiteFileFetch(SiteInfoBean bean) throws IOException WlG/7$  
{ Zb}=?fcL;@  
siteInfoBean = bean; n1!u aUC  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Yz{UP)TC  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); R=PjLH&)  
if(tmpFile.exists ()) i%-c/ lop  
{ Q@l3XNH|c  
bFirst = false; ^>]p4Q3 6  
read_nPos(); bD49$N?>  
} u6|7P<HUfb  
else "esV#%:#J  
{ iUSs)[]H>  
nStartPos = new long[bean.getNSplitter()]; *UEo&B2+  
nEndPos = new long[bean.getNSplitter()]; hX[hR  
} :a`l_RMU  
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} oBIKtS*L  
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public void run() UG1^G07s  
{ u*PN1E
 
//获得文件长度 =1LrU$\  
//分割文件 F#W'>WB
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//实例FileSplitterFetch ]k>S0  
//启动FileSplitterFetch线程 6B|IbQ^  
//等待子线程返回 wn|Sdp  
try{ , gz:2UY#  
if(bFirst) =Ermh7,  
{ x+^iEj`gk  
nFileLength = getFileSize(); /SP^fB*y  
if(nFileLength == -1) B;_M52-B  
{ .K:>`~<)  
System.err.println("File Length is not known!"); G$`/86A)  
} 4.R >mN[  
else if(nFileLength == -2) &~uzu{  
{ LVO`+:  
System.err.println("File is not access!"); -w^E~J0*L  
} wYNh0QlBH  
else ].`i`.T  
{ N"FQMxqm  
for(int i=0;i<nStartPos.length;i++) &K|CH? D  
{ Qs</.PO  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); opdi5e)jK  
}
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for(int i=0;i<nEndPos.length-1;i++) .y[=0K:  
{ QiB:K Pz[  
nEndPos = nStartPos[i+1]; Z\`uI+`  
} K]Ed-Tz8QZ  
nEndPos[nEndPos.length-1] = nFileLength; =j}]-!  
} kg9ZSkJr  
} qfG`H#cA<  
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}6ec2I%`o  
//启动子线程 keCM}V`?"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :8\z 0  
for(int i=0;i<nStartPos.length;i++) 6fQQKM@a|  
{ vvdC.4O  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7e>n{rl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), r!j_KiUy  
nStartPos,nEndPos,i); ~eE2!/%9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); z l@ <X0q  
fileSplitterFetch.start(); y\V!OY@  
} =][[TH  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f~8Xue,l"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 1j3mTP  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", v(]\o;/O  
nEndPos = " + nFileLength); '}]w=2Lf  
// fileSplitterFetch[nPos.length-1].start(); mI?AI7DqK  
57rc|]C  
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//等待子线程结束 yj"+!g  
//int count = 0; 8@Y]dzgjj  
//是否结束while循环 `3\5&Bf  
boolean breakWhile = false; s#64NG  
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while(!bStop) 29 ')Y|$,  
{ Lk=f^qJ ]  
write_nPos(); <.+hV4,3  
Utility.sleep(500); lc#su$xR>  
breakWhile = true; FL"7u2rh,  
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for(int i=0;i<nStartPos.length;i++) ^Jsx^?  
{ gQ/-.1Pz$  
if(!fileSplitterFetch.bDownOver) q>o1kTI  
{ 1i^
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breakWhile = false; R\ <HR9r  
break; ~ex1,J*}t  
} 6# ,2  
} UC\CCDV#^  
if(breakWhile) ?0Z?Z3)%w4  
break; fPa FL}&  
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//count++; \:%e 6M  
//if(count>4) " :@5|4qK  
// siteStop(); @=isN'>]O  
} |^8l8u  
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>  
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System.err.println("文件下载结束！"); xW!2[.O5H  
} ,*wa#[  
catch(Exception e){e.printStackTrace ();} Ae;> @k/|=  
} mfg{% .1  
o.*8$$  
rAM{<  
//获得文件长度 MCjf$pZN]  
public long getFileSize() _cQTQ  
{ @y2{LUJe  
int nFileLength = -1; >5'C<jc C  
try{ 9jCn|+  
URL url = new URL(siteInfoBean.getSSiteURL()); d[6[3B  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); q`{crY30  
httpConnection.setRequestProperty("User-Agent","NetFox"); pmv;M`_|R  
iQ~;to;Y  
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int responseCode=httpConnection.getResponseCode(); 'n6D3Vse  
if(responseCode>=400) )C|[j@MD  
{ Fr`"XH  
processErrorCode(responseCode); PsjSL8]  
return -2; //-2 represent access is error ,W'`rCxJ  
} !c4pFQB  
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String sHeader; ~Uz,%zU#3  
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for(int i=1;;i++) j(AN]g:  
{ " ;8H;U`  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]p:s5Q  
//Utility.log(in.readLine()); mG*[5?=r  
sHeader=httpConnection.getHeaderFieldKey(i); F\^9=}b_i  
if(sHeader!=null) :D\M.A  
{ xKi: 2  
if(sHeader.equals("Content-Length")) q@1b{q#C5  
{ rF'_YYpr>  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); z'z_6]5  
break; K-cRNt  
} Y`eU
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} (J I4ibP  
else 2f2Vy:&O_  
break; \fj*.[,  
} ANR?An  
} |08b=aR6ro  
catch(IOException e){e.printStackTrace ();} 1MkQ$v7m  
catch(Exception e){e.printStackTrace ();} wJ,l"bnq  
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Utility.log(nFileLength); "j#;MOK  
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return nFileLength; &FHzd/  
} 8b\XC%k  
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//保存下载信息（文件指针位置） 5 Sm9m*/  
private void write_nPos() c5Fl:=h  
{ >NwS0j$j@  
try{ 
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output = new DataOutputStream(new FileOutputStream(tmpFile)); lgWEB3f .  
output.writeInt(nStartPos.length); {]-AuC2E/0  
for(int i=0;i<nStartPos.length;i++) ' 5`w5swbc  
{ Ac{"$P`  
// output.writeLong(nPos); jrJ!A(<)  
output.writeLong(fileSplitterFetch.nStartPos); u*u3<YQ  
output.writeLong(fileSplitterFetch.nEndPos); 6b`3AAGU"  
} X` r~cc  
output.close(); |>X5@
 
} A/:^l%y,GZ  
catch(IOException e){e.printStackTrace ();} =]i[gs)B  
catch(Exception e){e.printStackTrace ();} %P@V7n  
} qtlXDgppO  
`>'%!E9G  
:E`/z@I  
//读取保存的下载信息（文件指针位置） 4}-{sS}MP  
private void read_nPos() +||y/}1  
{ <~s{&cL!%#  
try{ *f<+yF{=A  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); `#J0@ -  
int nCount = input.readInt(); Y=0D[o8  
nStartPos = new long[nCount]; #2 Gy=GvV  
nEndPos = new long[nCount]; 7-S?\:J  
for(int i=0;i<nStartPos.length;i++) b{4@~>i  
{ +OEqDXR+_  
nStartPos = input.readLong(); 2E7vuFH4c  
nEndPos = input.readLong(); Ilf;Q(*$>>  
} w1>uD]  
input.close(); X$mCn#8m  
} QAN :  
catch(IOException e){e.printStackTrace ();} V&e9?5@  
catch(Exception e){e.printStackTrace ();} .l1uqCuB  
} "L ,)4v/J  
% \N52  
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private void processErrorCode(int nErrorCode) l5
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{ TQhu$z<  
System.err.println("Error Code : " + nErrorCode); P)D2PVD  
} jgpSFb<9F  
5 1&||.  
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//停止文件下载 q%&JAX=  
public void siteStop() X"hdCY%  
{ pb8sx1.j;  
bStop = true; +hiskV@
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for(int i=0;i<nStartPos.length;i++) 
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fileSplitterFetch.splitterStop(); zH)M,+P  
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} R"Ff(1m  
} T- ~l2u|s  
//负责部分文件的抓取 Pk{eGG<F$  
**FileSplitterFetch.java 2&b?NqEeZ  
*/ %m
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package NetFox; L'A9TW2  
}Zuk}Og9+  
+wPXDN#R  
import java.io.*; ;zF3e&e(  
import java.net.*; JJE?!Yvc  
<A~a|A-QFR  
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public class FileSplitterFetch extends Thread { A  [c1E[  
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-6KNMk  
String sURL; //File URL r%=}e++^%  
long nStartPos; //File Snippet Start Position T5<851rH  
long nEndPos; //File Snippet End Position ,y>Sq +  
int nThreadID; //Thread's ID u$M,&Om  
boolean bDownOver = false; //Downing is over qnc?&f  
boolean bStop = false; //Stop identical oeKVcVP|'&  
FileAccessI fileAccessI = null; //File Access interface v~.nP} E^  
?Sj>b  
7oWT6Qa5  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 8GN_3pT  
{ sV']p#HK0  
this.sURL = sURL; (8Ptuh6\\2  
this.nStartPos = nStart; IoAG!cS  
this.nEndPos = nEnd; /8Wfs5N  
nThreadID = id; u2 a#qU5*  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 `W=3_  
} 6<hE]B)  
5 *R{N ~>  
6,~Y(#  
public void run() MrU0Jrk4+  
{ VY1&YR}Y  
while(nStartPos < nEndPos && !bStop) ,h<xL-  
{ :z-UnC||j  
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try{ .D8|_B  
URL url = new URL(sURL); [C-4*qOaa2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .91@T.  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1SK|4Am  
String sProperty = "bytes="+nStartPos+"-"; .Ld{QPa  
httpConnection.setRequestProperty("RANGE",sProperty); _GbwyfA n#  
Utility.log(sProperty); cfZ$V^xM  
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InputStream input = httpConnection.getInputStream(); '$q=r x  
//logResponseHead(httpConnection); kfW"vI+d  
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je#OV,uHM  
byte[] b = new byte[1024]; !E@4^A80\W  
int nRead; uB@~xQ_V  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) v? Ufx  
{ &#< M o  
nStartPos += fileAccessI.write(b,0,nRead); G^%FP!'D?  
//if(nThreadID == 1) 0d|DIT#>?  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
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} 6k9cvMs%H  
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YQ-!>3/)-  
Utility.log("Thread " + nThreadID + " is over!"); 8\BGL  
bDownOver = true; @{q:179w^  
//nPos = fileAccessI.write (b,0,nRead); cF V[k'F  
} +Y! P VMF  
catch(Exception e){e.printStackTrace ();} V] 0T P#  
} UTS.o#d  
} nl)l:A+q8  
"p@EY|Zv%I  
"xduh3/~=  
//打印回应的头信息 fMm.V=/+  
public void logResponseHead(HttpURLConnection con) =pk5'hBAi  
{ <zWMTVaC  
for(int i=1;;i++) W/@-i|v  
{ Kt5k_9
 
String header=con.getHeaderFieldKey(i); , G2(l  
if(header!=null) /$'|`jKsB  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 5Y4#aq   
Utility.log(header+" : "+con.getHeaderField(header)); %y|L'C,ge"  
else 1=L5=uz1d:  
break; MUW&m2  
} =kP|TR!o-  
} Liv.i;-qE  
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public void splitterStop() 90Bn}@t=Q  
{ *8Kx y@  
bStop = true; vdaG?+_o  
} s9rKXY',:l  
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} 8G )O,F7z  
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/* wx*03(|j;  
**FileAccess.java /<VR-yr  
*//文件访问(定位，写)  SH6+'7  
package NetFox; 5V*R
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import java.io.*; hX)PdRk#  
^xX1G_{  
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public class FileAccessI implements Serializable{ 7h#*djef  
2DNB?,uP,'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 A}4 ",  
RandomAccessFile oSavedFile; x8!uI)#tS  
long nPos; lj /IN[U/  
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POI|#[-V  
public FileAccessI() throws IOException c5(4rT{(m  
{ rrP_7D  
this("",0); -q30tO.  
} 3}2;*:p4Y  
lBzfBmEB  
'Px}#f0IR  
public FileAccessI(String sName,long nPos) throws IOException L\zyBfK}  
{ [NoOA  
oSavedFile = new RandomAccessFile(sName,"rw"); (Xl+Zi>\{  
this.nPos = nPos; $1y8X K7r  
oSavedFile.seek(nPos); 9]%2Yb8SC  
} 1]a\uq}  
1t/mq?z:  
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public synchronized int write(byte[] b,int nStart,int nLen) ]^53Qbrv  
{ tGJJ|mle>  
int n = -1; |OiM(E(  
try{ 5)C`W]JE  
oSavedFile.write(b,nStart,nLen); TSTkMlCG  
n = nLen; &3$FkU^F6  
} |Ae7wXOs  
catch(IOException e) m.68ctaa  
{ 8ly6CP+^B  
e.printStackTrace (); @|:yK|6O  
} muMd
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return n; Vg(FF"  
} 9qkJ<  
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} y!c<P,Lt3f  
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/* [jR>.H'  
**SiteInfoBean.java jqlfypU  
*/ u7SC_3R  
package NetFox; Rn*@)5  
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pQi|PQq  
public class SiteInfoBean { .I0M'L~!/L  
mu2|%$C;$  
!l5@L\  
private String sSiteURL; //Site's URL E9\u^"GVO  
private String sFilePath; //Saved File's Path v7/k0D .  
private String sFileName; //Saved File's Name ! u@JH`  
private int nSplitter; //Count of Splited Downloading File ZypK''&oc  
A=sz8?K+`  
[!#}#  
public SiteInfoBean() OX7a72z  
{//nSplitter的缺省值为5 WmOu#5*;  
//default value of nSplitter is 5 D?FmlDTr[  
this("","","",5); pVM1%n:#  
} *v$j n  
_*cKu>,O  
[A'e7Do%'  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) vdh[%T,&  
{ V4&a+MJ@  
sSiteURL= sURL; =zTpDL  
sFilePath = sPath; 6rM{r>  
sFileName = sName; vVZ+u4y  
this.nSplitter = nSpiltter; U|<>xe*|%  
;ojJXH~$}  
8)>4ZNXz  
} BOD!0CR5  
y;%\w-.\  
YU XxQ|  
public String getSSiteURL() x*p'm[Tdtm  
{ /9,y+"0SQz  
return sSiteURL; rk47$36X  
} ~iPXn1  
T7|=`~  
\]g51U!'  
public void setSSiteURL(String value) "
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{ p,tkVedR  
sSiteURL = value; \E'z+0  
} 9 e|[9  
uPC(|U%  
}:Y)DH%u  
public String getSFilePath() yMD3h$w3a  
{ 9fWR8iV  
return sFilePath; h;@>E:4Tg  
} '#>Fe`[  
\;iOQqv0&  
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public void setSFilePath(String value) P4LiU2C  
{ DXFDs=u  
sFilePath = value; 2PSkLS&IM  
} ~Kl"V%>  
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public String getSFileName() JmeE}:5lpj  
{ b|*+!v:I>T  
return sFileName; )3O#T$h  
} ^Nu j/  
 vY"I  
Z|fi$2k0!  
public void setSFileName(String value) KdD~;Ap$  
{  FLZ9Rg  
sFileName = value; n]7rHV}G  
} t1~k+  
A-d<[@d0  
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public int getNSplitter() p8"C`bCf  
{ 2b
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return nSplitter; FS!9 j8  
} _z1Qr?cY  
L@jpid95  
TaaCl#g$?  
public void setNSplitter(int nCount) cvf?ID84  
{ I+ 3qu=  
nSplitter = nCount; 6xY6EC  
} }eI9me@Aa  
}  j=G  
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>e(@!\ x  
/* 7]Hf3]e>/  
**Utility.java LNrM`3%2-  
*/ |`kkmq  
package NetFox; ;8f)p9vE  
k {vd1,HZ  
4E}Q<?UYSt  
public class Utility { b|G~0[g  
:7X{s4AU6  
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public Utility() N})vrB;1  
{ I 9?X  
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'66nqJb*  
} &U CtyCz  
n5efHJU  
//线程睡眠 L?P[{Ohh/  
public static void sleep(int nSecond) ^|vP").aQm  
{ Fp"c {  
try{ 9b&;4Yq!f  
Thread.sleep(nSecond); &j/,8 Z*  
} &~x|w6M]J  
catch(Exception e) xRO9o3  
{ Snn4RB<(  
e.printStackTrace (); wuxOFlrg  
} r+6 DlT a  
} @3 +   
q4'
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//日志 ??|,wIRz  
public static void log(String sMsg) A[`c+&  
{ ~(NFjCUY?  
System.err.println(sMsg); 1K)9fMr]  
} ~BgYD)ov  
n{qVF#N_  
\}<J>R@  
public static void log(int sMsg) bE=[P}E  
{ Jk:ZO|'Z  
System.err.println(sMsg); ()$m9%x  
} [9}<N2,9z  
} ,J<+Wxz  
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M0e&GR8<z>  
/* kmlO}0  
**TestMethod.java u[4h|*'"|  
*/ [H9<JdUZ  
package NetFox; V$iA3)7W%  
/,j'Vr\"  
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public class TestMethod { \f VX<L  
^JY:$)4["  
.b!HEi<F  
public TestMethod() ti]8_vP}*  
{ ///xx/weblogic60b2_win.exe teLZplC=f  
try{ {K|ds($ 5  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); J-G)mvkv  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); cg_tJ^vrY  
SiteFileFetch fileFetch = new SiteFileFetch(bean); _{}^]ZB  
fileFetch.start(); ae2I,Qt%  
} e5lJ)_o  
catch(Exception e){e.printStackTrace ();} Jvj* z6/a  
Cv&>:k0V  
9KT85t1#  
} )(1tDQ`L>  
n$>_2v  
"]=XB0)  
public static void main(String[] args) EiDpy#f}  
{ V' i@N  
new TestMethod(); Dr(;A>?qG  
} Ra^c5hP:.E  
} ycEp,V;[Z  
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