http断点续传简单实现（java)

/* V?O%kd  
**SiteFileFetch.java EIYM0vls(  
*/ jo(Q`oxm!>  
package NetFox; C5WCRg5&  
import java.io.*; GY",AL8f  
import java.net.*; kI
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public class SiteFileFetch extends Thread { *3ne(c
 
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SiteInfoBean siteInfoBean = null; //文件信息Bean dq8 /^1P  
long[] nStartPos; //开始位置 p;7 4+q  
long[] nEndPos; //结束位置 kR6 t .  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 PPqTmx5S  
long nFileLength; //文件长度 j^ _I{  
boolean bFirst = true; //是否第一次取文件 3N bn|_`(  
boolean bStop = false; //停止标志 !Q(xOc9>Ug  
File tmpFile; //文件下载的临时信息 }g*-Ty  
DataOutputStream output; //输出到文件的输出流 @*uX[)  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） {''|iwLr  
public SiteFileFetch(SiteInfoBean bean) throws IOException B![5+  
{ 'iVo,m[yKU  
siteInfoBean = bean; BH-[q9pf  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *QG3Jz
 
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); YMi(Cyja&  
if(tmpFile.exists ()) r~}}o o4K  
{ )*A,L%  
bFirst = false; '<0q"juXE  
read_nPos(); 6|KX8\,A@  
} TN %"RL  
else bSr 'ji  
{ r9M={jC  
nStartPos = new long[bean.getNSplitter()]; Z M+Hb_6f  
nEndPos = new long[bean.getNSplitter()]; {a3kn\6H0  
} ZmULy;{<)  
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} VRX" @uCD  
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public void run() qp W#!Vbx  
{ 2ZO'X9  
//获得文件长度 [)3 U])w/  
//分割文件 B (1,Rq[  
//实例FileSplitterFetch <]'"e]  
//启动FileSplitterFetch线程 p0rwiBC=q  
//等待子线程返回 @1F'V'  
try{ >$mSFJz5S  
if(bFirst) $&8h=e~]-  
{ (J*w./  
nFileLength = getFileSize(); )zXyV]xe  
if(nFileLength == -1) 7rSUSra  
{ (oXN>^-D  
System.err.println("File Length is not known!"); VWshFI  
} DVhTb  
else if(nFileLength == -2) 1qC:3 ;P  
{ ~+#--BhV  
System.err.println("File is not access!"); Uxemlp%%*  
} 5b#6 Y
 
else qP"JNswI_  
{ X[Ek'=}  
for(int i=0;i<nStartPos.length;i++) be:phS4vz  
{ -L9R&r#_e  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8'lhp2#h  
} <KwK tgzs  
for(int i=0;i<nEndPos.length-1;i++) Uk:.2%S2  
{ 16QbB;  
nEndPos = nStartPos[i+1]; z`/.v&<>V  
} #Q3PzDfj  
nEndPos[nEndPos.length-1] = nFileLength; Fd[h9 G  
} %?f:"  
} nuQ6X5>.=  
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//启动子线程 g`OOVaB  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; R*@[Pg*  
for(int i=0;i<nStartPos.length;i++) jBv$^L  
{ EB>B,#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]zyX@=mM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), L)lQ&z?  
nStartPos,nEndPos,i); OF&h=1De,  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V->%)d3i  
fileSplitterFetch.start(); b!]0mXU  
} ^W"Q(sh  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %kx ^/DH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !&`\ LJ=j  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", D4q>R;  
nEndPos = " + nFileLength); YvruK:I  
// fileSplitterFetch[nPos.length-1].start(); `OP>(bU0  
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6B''9V:s  
//等待子线程结束 PDIclIMS'F  
//int count = 0; m*!f%}T  
//是否结束while循环 4C1FPrh  
boolean breakWhile = false; 14D7U/zer  
*w/WHQ`xI  
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while(!bStop) 8rwYNb.P  
{ R|1xXDLm*E  
write_nPos(); ~pevU`}Uqc  
Utility.sleep(500); ^5]uBOv  
breakWhile = true; gKN}Of@^1  
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for(int i=0;i<nStartPos.length;i++) Vd+Q:L  
{ 5!AV!A_Jp  
if(!fileSplitterFetch.bDownOver) d;~ 3P   
{ rer|k<k;]G  
breakWhile = false; voV:H[RD9  
break; -+}5ma  
} jJVT_8J  
} &$c5~9p\B  
if(breakWhile) i<m$#6<Z  
break; +~d1;0l|  
|qlS6Aln  
x=5P+_  
//count++; e8WEz 4r_  
//if(count>4) L}W1*L$;<  
// siteStop(); ku9@&W+  
} wn+j39y?ZY  
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System.err.println("文件下载结束！"); t<
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} 3@)obb  
catch(Exception e){e.printStackTrace ();} :)p)=c8%  
} JoCA{Fa}  
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//获得文件长度 {pDTy7!Hs  
public long getFileSize() UP;Q=t  
{ A XBkJ'jd  
int nFileLength = -1; hOPe^e"  
try{ l(%k6  
URL url = new URL(siteInfoBean.getSSiteURL()); >BNw
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b]*X<,p  
httpConnection.setRequestProperty("User-Agent","NetFox"); cJ(BiL-uF  
M XZq  
_BV`,`8}  
int responseCode=httpConnection.getResponseCode(); 8xF)_UV  
if(responseCode>=400) Wp5]Uk  
{ B6bOEPQ  
processErrorCode(responseCode); H`m:X,6}
 
return -2; //-2 represent access is error oYz!O]j;a  
} TZ_rsj/t  
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String sHeader; gYatsFyL  
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for(int i=1;;i++) )O3jQ_q=  
{ QjA&IZEC  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); b~_B [cf  
//Utility.log(in.readLine()); 4:vTxNs&S  
sHeader=httpConnection.getHeaderFieldKey(i); z)lM2x>|*  
if(sHeader!=null) ]@X{dc  
{ 47IY|Jdz  
if(sHeader.equals("Content-Length")) r6`\d
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{ o+<29o  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); upypxC  
break; <jeh`g  
} XOrcygb2  
} akT|Y4KxD  
else Lt1U+o[ot  
break; =<{h^-j;a  
} Ic'Q5kfM  
} R]u (l+`  
catch(IOException e){e.printStackTrace ();} lv4(4$T  
catch(Exception e){e.printStackTrace ();} 90~*dN
k  
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Utility.log(nFileLength); &p5&=zV}  
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return nFileLength; @(-yrU  
} +?;j&p  
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//保存下载信息（文件指针位置） {FWyu5.  
private void write_nPos() s~^*+kq  
{ tBseqS3<  
try{ `(!NYx  
output = new DataOutputStream(new FileOutputStream(tmpFile)); j 1(T )T  
output.writeInt(nStartPos.length); *>k!hq;
j  
for(int i=0;i<nStartPos.length;i++) $A`xhh[  
{ EX:{EmaT  
// output.writeLong(nPos); W,3zL.qH"  
output.writeLong(fileSplitterFetch.nStartPos); o(qEkR:4kd  
output.writeLong(fileSplitterFetch.nEndPos); c3] C:t+  
} 3 >|uF  
output.close(); -Q$b7*"z(  
} -#aZF2z  
catch(IOException e){e.printStackTrace ();} 'M8aW!~  
catch(Exception e){e.printStackTrace ();} Wr5Q5s)c  
} EJLQ&oH[  
vU!8`x)  
Z:@6Lv?CN  
//读取保存的下载信息（文件指针位置） _gW{gLYyJ  
private void read_nPos() |5,<jyp  
{ tMFsA`ng  
try{ &~#iIk~%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); DLi?'K3t  
int nCount = input.readInt(); XJSa]P^B1  
nStartPos = new long[nCount]; EMlIxpCn:  
nEndPos = new long[nCount]; "jR]MZ  
for(int i=0;i<nStartPos.length;i++) >,"sHm}l%  
{ ,=|4:F9
  
nStartPos = input.readLong(); ` W4dx&  
nEndPos = input.readLong(); ne4c%?>t  
} CWi8Fv  
input.close(); < Dd%  
} W"Q!|#;l.  
catch(IOException e){e.printStackTrace ();} E-fr}R}  
catch(Exception e){e.printStackTrace ();} ',ZF5T5z@  
} 2n|CD|V$ux  
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private void processErrorCode(int nErrorCode) :p>hW!~  
{ Ma6W@S
 
System.err.println("Error Code : " + nErrorCode); ZenPw1-  
} S`iR9{+&  
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//停止文件下载 M
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public void siteStop() )K
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{ g9KTn4  
bStop = true; #cU^U#;=r  
for(int i=0;i<nStartPos.length;i++) AW~"yI<  
fileSplitterFetch.splitterStop(); }ptMjT{9  
.!RavEg+  
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} ,l HLH  
} {)@D`{$  
//负责部分文件的抓取 PKf:O  
**FileSplitterFetch.java exDkq0u]  
*/ Hi7y(h?wj  
package NetFox; 81F,Y)x.  
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import java.io.*; $^_|j1z#i  
import java.net.*; xWE8Wm  
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public class FileSplitterFetch extends Thread { &yIGr`;  
s-rfS7;  
%=Tr^{i  
String sURL; //File URL ;..o7I  
long nStartPos; //File Snippet Start Position 1] #9  
long nEndPos; //File Snippet End Position *Zbuq8>  
int nThreadID; //Thread's ID G[Tl
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boolean bDownOver = false; //Downing is over kl}Xmw{tJ  
boolean bStop = false; //Stop identical _xrwu;o0}  
FileAccessI fileAccessI = null; //File Access interface ,9of(T(~  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException wLJ]&puwm  
{ tous#(&pK  
this.sURL = sURL; S8vV!xO  
this.nStartPos = nStart; E m{aM  
this.nEndPos = nEnd; XOy2lJ/  
nThreadID = id; }Ln@R~[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~/-eyxLTm  
} -rSIBc:$8  
#0"~G][#  
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public void run() UBZ9A  
{ >#(n"RCHf  
while(nStartPos < nEndPos && !bStop) g|%L"-%gJ  
{ C#Bz>2;#  
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try{ L":bI&V?:  
URL url = new URL(sURL); _P7tnXww  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1S:|3W  
httpConnection.setRequestProperty("User-Agent","NetFox"); CN&  
String sProperty = "bytes="+nStartPos+"-"; *>q/WLR  
httpConnection.setRequestProperty("RANGE",sProperty); sZhMa>  
Utility.log(sProperty); 'Ot,H_pE  
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InputStream input = httpConnection.getInputStream(); @jy41eIo  
//logResponseHead(httpConnection); K#mOSY;}  
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byte[] b = new byte[1024]; uQqWew8l+  
int nRead; Pbu{'y3J  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) v?:: |{  
{ oPQtGl p  
nStartPos += fileAccessI.write(b,0,nRead); [xZU!=  
//if(nThreadID == 1) OMrc_)he\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $V>yXhTh  
} r[txlQI9  
+T{'V^  
#{J,kcxS  
Utility.log("Thread " + nThreadID + " is over!"); $_;e>*+x  
bDownOver = true; 1wj:aD?g  
//nPos = fileAccessI.write (b,0,nRead); If-_?wZe  
} <skajQQ  
catch(Exception e){e.printStackTrace ();} Vw
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} K>/%X!RW  
} \2C`<h$fN  
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//打印回应的头信息 R^#@lI~  
public void logResponseHead(HttpURLConnection con)
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{ =aG xg57  
for(int i=1;;i++) -yAQ  
{ vH[47CvG5  
String header=con.getHeaderFieldKey(i); s)J(/  
if(header!=null) #qBr/+b  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); nY%5cJ`"  
Utility.log(header+" : "+con.getHeaderField(header)); p#P~Q/;  
else /=?x{(B>  
break; q2aYEuu,  
} N)2f7j4C&  
} Z.PBu|Kx  
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public void splitterStop() ?~e
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{ fwR_OB:$  
bStop = true; 7- d.ZG  
} <O<LYN+(  
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} &[Xu!LP  
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k?B[>aQn.0  
/* dihjpI_  
**FileAccess.java Uz7oL8  
*//文件访问(定位，写) %r\n%$@_  
package NetFox; '9p@vi{\  
import java.io.*; eV^d6T$  
"r4AY  
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public class FileAccessI implements Serializable{ y&~w2{a  
\>. LW9  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 1/+C5Bp*  
RandomAccessFile oSavedFile; {$D,?V@%_  
long nPos; >SF Uy\3  
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public FileAccessI() throws IOException f"[J"j8  
{ *D}0[|O  
this("",0); f5*k7fg  
} 4S"\~><  
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public FileAccessI(String sName,long nPos) throws IOException +j_;(Gw7  
{ |y;}zQB-dH  
oSavedFile = new RandomAccessFile(sName,"rw"); 3981
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this.nPos = nPos; VZr>U*J[:  
oSavedFile.seek(nPos); {Bs~lC$  
} ia&AW  
(_kp{0r#  
e~%  ;K4  
public synchronized int write(byte[] b,int nStart,int nLen) (/d5UIM{&  
{ 94uNI8  
int n = -1; }"vW4   
try{ vy2Q g  
oSavedFile.write(b,nStart,nLen); Y`7~Am/r;&  
n = nLen; j`'`)3f  
} T3UMCqc=  
catch(IOException e) QZp6YSz.4  
{ : JzI>/  
e.printStackTrace (); ,j
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} )UgX3+@  
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return n; 5,qj7HZF  
} _R'Fco  
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} ?&G`{Ey  
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/* Xp\/YJOibd  
**SiteInfoBean.java OMhef,,H  
*/ w{[=l6L m  
package NetFox; 4%4avEa"w  
(fNUj4[  
v 8T$ &-HJ  
public class SiteInfoBean { '
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#/"8F O%~p  
mpAR7AG6  
private String sSiteURL; //Site's URL W>r#RXmh  
private String sFilePath; //Saved File's Path ?]fF3SJk  
private String sFileName; //Saved File's Name 2XTPBZNe  
private int nSplitter; //Count of Splited Downloading File bmNq[}  
7{e{9QbJ4  
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public SiteInfoBean() 3!Sp0P  
{//nSplitter的缺省值为5 :q8b;*:  
//default value of nSplitter is 5 3czeT
j  
this("","","",5); [U}+sTQ  
} =PRx?q`d  
S)QAXjH  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) +4[^!q* H  
{ s2?T5oWU  
sSiteURL= sURL; b KTcZG  
sFilePath = sPath; tQZs.1=z  
sFileName = sName; &PkLp4mQ  
this.nSplitter = nSpiltter; p raaY}}  
@L.82p{h  
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} M02uO`Y9  
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public String getSSiteURL() ]
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{ mNmLyU=d  
return sSiteURL; q@b|F-  
} \V9Z#>  
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public void setSSiteURL(String value) RoCfJ65  
{ 0|R#Tb;Y  
sSiteURL = value; ;a-$D]Db  
} <0yE 5Mrf  
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public String getSFilePath() ??n*2s@t  
{ /Q,{?';~  
return sFilePath; W@yJAQ  
} c/B'jPt  
66^ycZCH  
&1+X\c+tb  
public void setSFilePath(String value) '9c2Q/  
{ jiF?fX@  
sFilePath = value; 4iW'kuK  
} D:Q 21Ch  
Ib
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>^Se'SE]  
public String getSFileName() Hm+ODv9  
{ D")_;NLE1  
return sFileName; Lh.`C7]
  
} sp@E8G%xO  
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public void setSFileName(String value) kId n6 Wx,  
{ A AHt218  
sFileName = value; J8Yd1.Qj  
} `
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mhW-J6u*  
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public int getNSplitter() &$`yo`  
{ DGevE~  
return nSplitter; _fZZ_0\Q  
} Oy 2+b1{  
j5 g# 
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public void setNSplitter(int nCount) )K'N(w  
{ aZEn6*0B  
nSplitter = nCount; zG e'*Qei  
} /r12h|  
} v)2M1  
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b)9'bJRvU  
/* S(\9T1DVe  
**Utility.java -=.V '  
*/ ?<6CFH]  
package NetFox; l4TpH|k  
'ejvH;V3i  
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public class Utility { 0flg=U9  
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public Utility() &Q}*+Y]G  
{ Xn~I=Ml d  
$.Q$`/dF  
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} Isx#9C  
 BUwONF  
//线程睡眠 RxMH!^  
public static void sleep(int nSecond) ORu2V#
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{ -{`@=U  
try{ |Yq$sU  
Thread.sleep(nSecond); c{[q>@y pK  
} A>{p2?`+!  
catch(Exception e) Fq9Q+RNMZL  
{ zD3mX<sw  
e.printStackTrace (); 9<Kj6t_  
} +:3*  
} gIA@l`
"  
sBV4)xM  
//日志 1Z{ZV.!  
public static void log(String sMsg) lC=~$c:  
{ ;(
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System.err.println(sMsg); au,t%8AC  
} ^<X@s1^#  
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.(Qx{r$  
public static void log(int sMsg) ,RN:^5 p  
{ "QvmqI>  
System.err.println(sMsg); QMEcQV
>  
} (|wz7AY2  
} R0oKbs{  
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G|\^{5  
/* f<A5?eKw  
**TestMethod.java .Vq)zi1<  
*/ ]tY ^0a  
package NetFox; Dde]I_f
}  
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public class TestMethod { #M A4  
#[#KL/i)$  
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public TestMethod() b*e
f);  
{ ///xx/weblogic60b2_win.exe ':R,53tjl  
try{ 7mm1P9Z  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); f-nz{U  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); g R nOd  
SiteFileFetch fileFetch = new SiteFileFetch(bean); t#!yrQ..'G  
fileFetch.start();  ["}rk  
} @,XSs  
catch(Exception e){e.printStackTrace ();} 2 1PFR:lP7  
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/t-fjB{=G  
} vd6l7"0/  
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6=N`wi  
public static void main(String[] args) hVUP4 A  
{ oq*N_mP0  
new TestMethod(); UJs$q\#RO  
} gl&5l1&  
} h~wi6^{&Y  
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