http断点续传简单实现（java)

/* "wc<B4"  
**SiteFileFetch.java o !7va"  
*/ 8cQ'dL`(  
package NetFox; 6w77YTJ  
import java.io.*; q cno^8R  
import java.net.*; ~QVH<`sn  

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public class SiteFileFetch extends Thread { fc@A0Hf  
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SiteInfoBean siteInfoBean = null; //文件信息Bean )`}:8y?  
long[] nStartPos; //开始位置 $od7;%  
long[] nEndPos; //结束位置 !!ya  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 =\d?'dII:  
long nFileLength; //文件长度 i mM_H;-X  
boolean bFirst = true; //是否第一次取文件 ']oQ]Yx0  
boolean bStop = false; //停止标志 D`AsRd  
File tmpFile; //文件下载的临时信息 L0]_X#s>#  
DataOutputStream output; //输出到文件的输出流 ItCv.yv35  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ?fS9J  
public SiteFileFetch(SiteInfoBean bean) throws IOException |7Kbpj  
{ QCJM&  
siteInfoBean = bean; C*lJrFpB  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ?1".;foZ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); A\;U3Zu  
if(tmpFile.exists ()) -^wl>}#*T3  
{ hzC>~Ub5  
bFirst = false; Rva$IX^]  
read_nPos(); Vz[C=_m  
} 9ll~~zF99|  
else t>sE x:  
{ 6zn5UW#q  
nStartPos = new long[bean.getNSplitter()]; Er[A X.3  
nEndPos = new long[bean.getNSplitter()]; -{_PuJ "  
} 1nOCQ\$l  
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} \C1nZk?3  
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public void run() fn!KQ`,#  
{ Xry47a )  
//获得文件长度 .[ mRM  
//分割文件 $mB;K]m  
//实例FileSplitterFetch ]:\dPw
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//启动FileSplitterFetch线程 v.ui
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//等待子线程返回 E~:x(5'%d  
try{ &VcV$8k  
if(bFirst) Q
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{ Tb-F]lg$  
nFileLength = getFileSize(); 8x{'@WCG%  
if(nFileLength == -1) i 3SHg\~Z  
{ .>nRzgo  
System.err.println("File Length is not known!"); &t-kpA|EG  
} {}Za_(Y,]  
else if(nFileLength == -2) nNU2([  
{ xP,hTE  
System.err.println("File is not access!"); #5j\C+P}|  
} n-OL0$Xu  
else \^%}M!tan  
{ eR"<33{  
for(int i=0;i<nStartPos.length;i++) I!?}jo3  
{ SZ$Kz n  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); PiYxk+N  
} C>w|a  
for(int i=0;i<nEndPos.length-1;i++) NN`uI6=  
{ Tu7QCr5*  
nEndPos = nStartPos[i+1]; Ub!(H^zu  
} C2Tyoza  
nEndPos[nEndPos.length-1] = nFileLength; ?K\axf>F  
} mdgi5v  
} #lW`{i  
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g  
.VzT:4-<Q"  
//启动子线程 e)O4^#i  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; # 4PVVu<  
for(int i=0;i<nStartPos.length;i++) ^ovR7+V  
{  ][h}  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), e@OX_t_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), (*)hD(C5  
nStartPos,nEndPos,i); $ DSZO!pB  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {,~3.5u   
fileSplitterFetch.start(); }~e%J(  
} /Mu@,)''  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Hg$lXtn]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]wG{!0pl  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", v oj^pzZ  
nEndPos = " + nFileLength); "!%l/_p?  
// fileSplitterFetch[nPos.length-1].start(); 'CkIz"Wd  
.xWC{}7[  
n#OB%@]<V  
//等待子线程结束 %Qdn  
//int count = 0; DZPPJ2}  
//是否结束while循环 5,6"&vU,  
boolean breakWhile = false; 3x'|]Ns  
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xx%j.zDI]  
while(!bStop) 1Z~FCJz  
{ lv+TD!b   
write_nPos(); b7?hI  
Utility.sleep(500); (c &mCJN  
breakWhile = true; 8C9-_Ng`  
DX K?Cv71z  
<;Zmjeb+#  
for(int i=0;i<nStartPos.length;i++) (rm?jDm   
{ I75DUJqy]  
if(!fileSplitterFetch.bDownOver) o="M  
{ -fHy-Oh  
breakWhile = false; 8&`LYdzt  
break; u frL<]A  
} pohp&Tcm  
} }oGA-Qc}B  
if(breakWhile) y ~!Zg}o  
break; 'Xq|Kf (  
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 DwE[D]7o  
//count++; 8i#2d1O  
//if(count>4) {:$>t~=D  
// siteStop(); f5VLw`m}.8  
} ]*[ 2$  
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System.err.println("文件下载结束！"); S8j{V5R'  
} GM f `A,>  
catch(Exception e){e.printStackTrace ();} A!WKnb_`  
} Lh
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//获得文件长度 }.m<  
public long getFileSize() mQ26K~  
{ V_}"+&W9  
int nFileLength = -1; Mc_YPR:
C  
try{ ARwD~Tr  
URL url = new URL(siteInfoBean.getSSiteURL()); hxd`OG<gF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c"V"zg22  
httpConnection.setRequestProperty("User-Agent","NetFox"); EPM
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int responseCode=httpConnection.getResponseCode(); Nk VK  
if(responseCode>=400) -g Sa_8R  
{ 9YQb&  
processErrorCode(responseCode); }DfshZ0QM  
return -2; //-2 represent access is error ?2{Gn-{  
} j8{i#;s!"  
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A,hJIe  
String sHeader; Jg\zdi:t  
1&evG-#<:  
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for(int i=1;;i++) BBRR
)  
{ yyRiP|hJ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >#~& -3  
//Utility.log(in.readLine()); cr?Q[8%t1  
sHeader=httpConnection.getHeaderFieldKey(i); (X1e5j>Ru  
if(sHeader!=null) 5Y'qaIFR  
{ (%e.:W${  
if(sHeader.equals("Content-Length")) ukfQe }I  
{ *
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); R_ ,UMt  
break; K'Tm_"[u  
} eH3JyzzP,  
} x?p1 HUK  
else [.'|_l  
break; +]A:M6P:{v  
} +N9X/QFKV  
} \y)rt )  
catch(IOException e){e.printStackTrace ();} zRl3KjET  
catch(Exception e){e.printStackTrace ();} eJVjuG  
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Utility.log(nFileLength); #ASz;$P  
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return nFileLength; EXw
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} udF~5w H  
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//保存下载信息（文件指针位置） ^f &XQQY  
private void write_nPos() .hP D$o  
{ `PdQX.wN  
try{ [vK^Um  
output = new DataOutputStream(new FileOutputStream(tmpFile)); _AYK435>N  
output.writeInt(nStartPos.length); Xy&A~F  
for(int i=0;i<nStartPos.length;i++) dvx#q5f_S  
{ G<8/F<m/  
// output.writeLong(nPos); fue(UMF~  
output.writeLong(fileSplitterFetch.nStartPos); }6}l7x  
output.writeLong(fileSplitterFetch.nEndPos); )!Z*.?  
} dulI&_x  
output.close(); kr5">"7  
} uaGk6S  
catch(IOException e){e.printStackTrace ();} ]^n7  
catch(Exception e){e.printStackTrace ();} vq0Tk bzs  
} qIE9$7*X  
<8i//HOE  
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//读取保存的下载信息（文件指针位置） o>i4CCU+  
private void read_nPos() 4*#18<u5  
{ <QAFL uey  
try{ >`mVY=Hi  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); gHEu/8E  
int nCount = input.readInt(); f:,DWw`B  
nStartPos = new long[nCount]; _|\~q[ep  
nEndPos = new long[nCount]; LTCb@L{^i  
for(int i=0;i<nStartPos.length;i++) x8\?}UnB  
{ fLD,5SN  
nStartPos = input.readLong(); TG?brgW  
nEndPos = input.readLong(); ]BZA:dd.G  
} G1tY)_-8[  
input.close(); T#Z^s~7&I  
} A_ZY=jP   
catch(IOException e){e.printStackTrace ();} 7\[@m3s  
catch(Exception e){e.printStackTrace ();} =
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} oj<gD  
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private void processErrorCode(int nErrorCode) NiK4d{E&  
{ I@~QV@U  
System.err.println("Error Code : " + nErrorCode); Tc:)- z[o  
} 6=/F$|  
V>LwqS~`  
7#a-u<HF"  
//停止文件下载 gp?uHKsM  
public void siteStop() SmH=e@y~Lx  
{ qkY:3O
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bStop = true; EjR9JUu  
for(int i=0;i<nStartPos.length;i++) k FD;i  
fileSplitterFetch.splitterStop(); 'ya{9EdlT  
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} g2ixx+`?|:  
} XFpjYwn  
//负责部分文件的抓取
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**FileSplitterFetch.java 69Ne
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*/ Y=I'czg  
package NetFox; fOGFq1
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import java.io.*; Eyqa?$R  
import java.net.*; aFm_;\  
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public class FileSplitterFetch extends Thread { ..5CC;B  
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String sURL; //File URL 1n8/r}q'H  
long nStartPos; //File Snippet Start Position 9;u@q%;!k  
long nEndPos; //File Snippet End Position Iyn(?w  
int nThreadID; //Thread's ID bsli0FJSh'  
boolean bDownOver = false; //Downing is over yx[/|nZDC4  
boolean bStop = false; //Stop identical Q&tG4f<  
FileAccessI fileAccessI = null; //File Access interface :eCwY  
3;9^  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException {}n^cq  
{ |YWD8 +  
this.sURL = sURL; [|$h*YK  
this.nStartPos = nStart; JXQO~zj  
this.nEndPos = nEnd; >Cp0.A:UC#  
nThreadID = id; jB2[(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 g:@#@1rB6  
} c)85=T6*aA  
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public void run() ;[DU%f  
{ M7~2iU<#  
while(nStartPos < nEndPos && !bStop) H*R"ntI?w  
{ IEi^kJflU  
KV *#T20T  
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try{ bAqA1y3=  
URL url = new URL(sURL); f8dB-FlMm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _V6ukd"B~  
httpConnection.setRequestProperty("User-Agent","NetFox"); <%eG:n,#  
String sProperty = "bytes="+nStartPos+"-"; (L&d!$,Dv  
httpConnection.setRequestProperty("RANGE",sProperty); {!L~@r  
Utility.log(sProperty); ;)*eo_tQ  
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InputStream input = httpConnection.getInputStream(); a;+9mDXx:  
//logResponseHead(httpConnection); *g2x%aZWbG  
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byte[] b = new byte[1024]; ^09,"<@k  
int nRead; >y3=|  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) PJH&  
{ /U9"wvg  
nStartPos += fileAccessI.write(b,0,nRead); h:|qC`}  
//if(nThreadID == 1) F]&*ow  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); UCjld  
} `|q(h Ow2  
~9@UjQ^)F  
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Utility.log("Thread " + nThreadID + " is over!"); b\2 ds,  
bDownOver = true; /\n-P'}  
//nPos = fileAccessI.write (b,0,nRead); evmeqQG=  
} G 3ptx! D  
catch(Exception e){e.printStackTrace ();} bk[!8-b/a  
} |+9&rAg  
} :V||c5B+  
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//打印回应的头信息 cr;da)  
public void logResponseHead(HttpURLConnection con) +ZP7{%  
{ f/?P514h  
for(int i=1;;i++) ECmW`#Otb)  
{ 'I;zJ`Trd  
String header=con.getHeaderFieldKey(i); OjA,]Gv6  
if(header!=null) 9\(| D#  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Q7CsJzk~)  
Utility.log(header+" : "+con.getHeaderField(header)); t]G:L}AOl  
else @H8EWTZ  
break; _+MJ%'>S
 
} _Fg5A7or  
} FS1z`wYP  
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public void splitterStop() \i&<s;  
{ 'J|_2*  
bStop = true; )+Pus~w  
} N'=gep0
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} mX|ojZ  
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/* 69.NPy@  
**FileAccess.java L}NSR  
*//文件访问(定位，写) 93hxSRw  
package NetFox; ddR>7d}N  
import java.io.*; -s/ea~=R  
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`  
public class FileAccessI implements Serializable{ RG`1en  
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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 !|>"o7  
RandomAccessFile oSavedFile; :BTq!>s  
long nPos; TS5Q1+hWHV  
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public FileAccessI() throws IOException HpnWoDM  
{ "zy7C*)>r  
this("",0); LreP4dRe  
} lw5`p,`  
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public FileAccessI(String sName,long nPos) throws IOException hR|MEn6KC  
{ 8dyg1F  
oSavedFile = new RandomAccessFile(sName,"rw"); S21,VpW\  
this.nPos = nPos; POR\e|hRT]  
oSavedFile.seek(nPos); !{41!O,K#  
} 7=, ;h  
lb1Xsgm{  
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public synchronized int write(byte[] b,int nStart,int nLen) Ecx
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{ kO-(~];  
int n = -1; /H+a0`/  
try{ M& CqSd  
oSavedFile.write(b,nStart,nLen); n{SJ_S#a.a  
n = nLen; 2)~>
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} '[O;zJN;  
catch(IOException e) y18Y:)DkL  
{ Pr,q*_Yy  
e.printStackTrace (); &]-DqK7  
} s(roJbJ_;  
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return n; IdxzE_@  
} G<;*SYAb  
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} _n\GNUA  
dcWD(-  
##4HYQ%E  
/* Y:)e(c"A  
**SiteInfoBean.java fa2kG&, _  
*/ U|j`e5)  
package NetFox; 5.J.RE"M  
01(AK%e  
-+-_I*(  
public class SiteInfoBean { &XU
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>~+ELVB&  
U\!X,a*ts{  
private String sSiteURL; //Site's URL eO[b1]WLP  
private String sFilePath; //Saved File's Path @2v_pJy^  
private String sFileName; //Saved File's Name 2SR:FUV/  
private int nSplitter; //Count of Splited Downloading File !m?-!:  
.Rf_Cl  
P J[`|  
public SiteInfoBean() K@w{"7}  
{//nSplitter的缺省值为5 4tmAzD  
//default value of nSplitter is 5 gt w Q-  
this("","","",5); r^ ZEImjc  
} ~gRf:VXX=_  
q?/a
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SGlNKA},A  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [0D.K}7|  
{ fZA4q0  
sSiteURL= sURL; c6]D-YNFG  
sFilePath = sPath; &W6^sj*k5U  
sFileName = sName; "AGLVp.zT  
this.nSplitter = nSpiltter; ]~hk6kS8Q  
"OnGE$  
s.NGA.]$  
} 85xR2<:  
/J6rv((  
EG |A_m85  
public String getSSiteURL() ^eYVWQ'  
{ tT?cBg{  
return sSiteURL; 7o5BXF  
} fMyti$1~  
@@%.t|=  
pr UM-u8  
public void setSSiteURL(String value) xAMW-eF?d  
{ LOV)3{m  
sSiteURL = value; Jz *;q
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} x0w4)Ic5  
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public String getSFilePath() s>n)B^64W  
{ ax5<#3__  
return sFilePath; G?/DrnK:  
} L.0mk_&  
v9O~@v{=  
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public void setSFilePath(String value) 8k1Dj1@0z  
{ +-CtjhoS  
sFilePath = value; N7 $I^?<  
} )*x6 FfTUd  
Jd^,]  
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public String getSFileName() G..aiA  
{ r/6o \-  
return sFileName; ILShd)]Rw  
} XtSkh] #z!  
74k dsgQf  
@>>~CZ`l  
public void setSFileName(String value) M>ruKHipFE  
{ x!58c
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sFileName = value; .j<]mUY  
} "v({,  
KRMQtgahc  
$jqq `n_  
public int getNSplitter() WQL\y3f5  
{ x$Oq0d{
T  
return nSplitter; 3e;^/kf<9  
} mtmjZP(w   
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qUGC"<W  
public void setNSplitter(int nCount) .ndC
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{ aYS!xh206  
nSplitter = nCount; 4\u1TYR  
} 27O|).yKX  
} jun_QiU:2  
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T)TfB(  
/* |G,tlchprs  
**Utility.java y8!4q  
*/ mmEYup(l0;  
package NetFox; Za3]d+qm  
vZ&T}H~8  
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public class Utility { Hmd] FC,_  
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-
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public Utility() #W'HR
 
{ rrqR}}l  
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} >x+6{^}Q>  
aM2l2  
//线程睡眠 ?Exv|e  
public static void sleep(int nSecond) qx8fRIK%  
{ MgOR2,cR  
try{ +"cq(Y@  
Thread.sleep(nSecond); 6)-X  
} */|lJm'R  
catch(Exception e) (\a]"g,]v  
{ /!Wu D\B  
e.printStackTrace (); Hh-+/sO~"  
} c5l.B#-lY  
} &7b|4a8B%  
v'qG26
  
//日志 hMUs" <.  
public static void log(String sMsg) ') gi%  
{ v!Pb`LCqK  
System.err.println(sMsg); 8x8uo  
} =aj/,Q]  
feNdMR7eM  
7_Z#m (  
public static void log(int sMsg) &nkW1Ner9  
{ LbG_z =A  
System.err.println(sMsg); qg!|l7e  
} |8=nL$u  
} jJY"{foWV  
\ 3?LqJ  
]dk8lZ;bo  
/* kc @[9eV  
**TestMethod.java n;U`m$vL%  
*/ 5ish\"  
package NetFox; PSVc+s[Q+V  
Xn,v]$M!  
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public class TestMethod { g'=B%eO$j:  
x.zbD8l/9  
: G`hm{  
public TestMethod() )m{Ye0!RD  
{ ///xx/weblogic60b2_win.exe {h2TD P  
try{ 'XofD}dm  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %4 XJn@J  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); J9Ou+6u(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ,FMx5$  
fileFetch.start(); :ORR_f`>  
} 6,LubZFD  
catch(Exception e){e.printStackTrace ();} QgD g}\P  
]%Nlv(  

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} ]f: v,a  
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!{.#  
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public static void main(String[] args) U uM$~qf/K  
{ a9Z%JS]  
new TestMethod(); ;?~$h-9)  
} R:AA,^Z  
} ^/=#UQ*k  
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