http断点续传简单实现（java)

/* 0`A~HH}  
**SiteFileFetch.java S^<g_q  
*/ |7pR)KH3  
package NetFox; \Z/)Y;|mi0  
import java.io.*; { e5/+W  
import java.net.*; tP%{P"g
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public class SiteFileFetch extends Thread { -,{-bi  
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SiteInfoBean siteInfoBean = null; //文件信息Bean j$Je6zq0x  
long[] nStartPos; //开始位置 ,SiY;(b=\  
long[] nEndPos; //结束位置 U*P. :BvG  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *(>}Y  
long nFileLength; //文件长度 dG71*)<)t  
boolean bFirst = true; //是否第一次取文件 }sFm9j7yR  
boolean bStop = false; //停止标志 Iu*^xn  
File tmpFile; //文件下载的临时信息 C2w2252T  
DataOutputStream output; //输出到文件的输出流 5W@jfh)  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） D.6,VY H  
public SiteFileFetch(SiteInfoBean bean) throws IOException -+em!g'  
{ 'EfR|7m  
siteInfoBean = bean; 4r0b)Y&I  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Yl$
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); g@Qgxsyk>  
if(tmpFile.exists ()) b(I2m  
{ PeE/iZ.  
bFirst = false; .*JA!B  
read_nPos(); F5qFYL;  
} AkT<2H|4  
else A &9(mB  
{ okFvn;  
nStartPos = new long[bean.getNSplitter()]; T'aec]u  
nEndPos = new long[bean.getNSplitter()]; @(i!YL  
} {?}*1,I  
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} "h7tnMS  
) (Tom9^  
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public void run() S"hTE7`  
{ S$^
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//获得文件长度 GzTq5uU&  
//分割文件 X*7\lf2  
//实例FileSplitterFetch E|$Oha[  
//启动FileSplitterFetch线程 )CS.F=  
//等待子线程返回 `K >?j
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try{ oo$MWN8a>r  
if(bFirst) o(Cey7  
{ 02k4N%  
nFileLength = getFileSize(); xlR2|4|8  
if(nFileLength == -1) 35x 0T/8  
{ hwDbs[:  
System.err.println("File Length is not known!"); X5*C+ I=2  
} Y}DonF  
else if(nFileLength == -2) =0'q!}._!  
{ ]k8/#@19  
System.err.println("File is not access!"); irZFV  
} Kw`VrcwjT  
else eb8w~  
{ s$*'^:  
for(int i=0;i<nStartPos.length;i++) h`}3h< 8  
{ m%8qZzqk  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ;!T{%-tP  
} ?n\*,{9  
for(int i=0;i<nEndPos.length-1;i++) .~gl19#:
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{ nB ".'=  
nEndPos = nStartPos[i+1]; Jj^GWZRu  
} w_iamqe,  
nEndPos[nEndPos.length-1] = nFileLength; (:+>#V)pZ  
} T^}  
} X+n`qiwq  
*}):<nB$^  
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//启动子线程 N|2y"5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; l~Lb!;,dN  
for(int i=0;i<nStartPos.length;i++) )2E%b+"  
{ 7a$G@  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), b( ^^m:(w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), swc@34ei\  
nStartPos,nEndPos,i); oAZh~~tp  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); te4= S  
fileSplitterFetch.start(); VRW]a  
} AP\ofLmq  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), v1.q$ f^(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Us~ X9n_F  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !z zW2>  
nEndPos = " + nFileLength); BXUF^Hj%  
// fileSplitterFetch[nPos.length-1].start(); mEuHl>  
kDz>r#%  
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//等待子线程结束 2PSTGG8JV  
//int count = 0; 7> Pgc
 
//是否结束while循环 K$REZe  
boolean breakWhile = false; )DUL)S  
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while(!bStop) (a6?s{(  
{ m^{ xd2  
write_nPos(); )-/gLZsx  
Utility.sleep(500); cub<G!K  
breakWhile = true; ^`qPs/b  
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for(int i=0;i<nStartPos.length;i++) WO,xM
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{ [ev-^[  
if(!fileSplitterFetch.bDownOver) cVq}c?  
{ ZZ)G5ji  
breakWhile = false;  9|S`ub'  
break; a1MFjmq  
} 2#_38=K=@  
} 5`E))?*"Pe  
if(breakWhile) \T-~JQVj  
break; `HX3|w6W;  
/CT(k1>  
*[kxF*^  
//count++; [B?z1z8l  
//if(count>4) ?Cci:Lin  
// siteStop(); O(OmGu4%  
} n!N\zx8  
LN!W(n(  
/b.oEGqZX  
System.err.println("文件下载结束！"); 8t.dPy<  
} N)43
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catch(Exception e){e.printStackTrace ();} =V^@%YIn  
} ur2!#bU9  
xKJ>gr"w#  
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//获得文件长度 En9R>A;`  
public long getFileSize() %3a|<6  
{ (clU$m+oXX  
int nFileLength = -1; Ls:=A6AGM  
try{ "'eWn6O(  
URL url = new URL(siteInfoBean.getSSiteURL()); <4D%v"zRP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); hr U :Wr  
httpConnection.setRequestProperty("User-Agent","NetFox"); Vf{2dZZ{1  
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int responseCode=httpConnection.getResponseCode(); h}=M^SL  
if(responseCode>=400) \OHv|8!EI@  
{ Z|`fHO3j  
processErrorCode(responseCode); =%h~/,  
return -2; //-2 represent access is error
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} [a8+(  
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String sHeader; FWTx&Ip  
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for(int i=1;;i++) 2;N@aZX  
{ /= ^L iP  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9!t4>  
//Utility.log(in.readLine()); !O\X+#j  
sHeader=httpConnection.getHeaderFieldKey(i); t>U!Zal"  
if(sHeader!=null) gEKO128  
{ qB JRS'6'9  
if(sHeader.equals("Content-Length")) sA_X<>vAKJ  
{ kQ}s/*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); +?e}<#vd'?  
break; &LU'.jY  
} jpO38H0)  
} dB`b9)Tk0z  
else YMAQ+A!  
break; <-|SIF  
} SLA#= K  
} L<@&nx  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} R|t;p!T  
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Utility.log(nFileLength); @Qo,p  
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return nFileLength; #'NY}6cb$  
} KF$%q((  
Cj$H[K}>  
d[U1.SNL  
//保存下载信息（文件指针位置） 5<r)+?!n  
private void write_nPos() ]hUKuef  
{ ?-{IsF^  
try{ 6{^*JC5nj  
output = new DataOutputStream(new FileOutputStream(tmpFile)); cMtJy"kK  
output.writeInt(nStartPos.length); B&nw#saz.  
for(int i=0;i<nStartPos.length;i++) v@,XinB[  
{ N<bD  
// output.writeLong(nPos); 3"B+xbe=  
output.writeLong(fileSplitterFetch.nStartPos); ' C6:e?R  
output.writeLong(fileSplitterFetch.nEndPos); U$$3'n  
} 8DT@h8tA  
output.close(); U]j&cFbn5_  
} u<q)SQ1  
catch(IOException e){e.printStackTrace ();} jf7pl8gv  
catch(Exception e){e.printStackTrace ();} Vw?P.4  
} Ty}R^cy{d  
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//读取保存的下载信息（文件指针位置） x9\J1\  
private void read_nPos() J=L`]XE  
{ GG>Y/;^  
try{ ./)j5M  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); J/gQQ.s  
int nCount = input.readInt(); (lb`#TTGx  
nStartPos = new long[nCount]; &U0WkW  
nEndPos = new long[nCount]; r1hD %a  
for(int i=0;i<nStartPos.length;i++) ZE ^u.>5  
{ G,/Gq+WX  
nStartPos = input.readLong(); eu=|t&FKk  
nEndPos = input.readLong(); 'Ix5,^M}B  
} g$gVm:=  
input.close(); V*kznm  
} j%GbgJ  
catch(IOException e){e.printStackTrace ();} {"\q(R0  
catch(Exception e){e.printStackTrace ();} 2q|_Dma  
} _"v~"k 90^  
4Qhx[Hv>(  
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private void processErrorCode(int nErrorCode) T/5nu?v  
{ *<CxFy;|  
System.err.println("Error Code : " + nErrorCode); Obg@YIwn  
} }*ODM6  
Z c<]^QR  
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//停止文件下载 I &cX8Tw  
public void siteStop() 9`,,%vdj  
{ C*]AL/  
bStop = true; ,FS?"Ni  
for(int i=0;i<nStartPos.length;i++) T*p|'Q`  
fileSplitterFetch.splitterStop(); ;_wMWl0F  
],$6&Cm  
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} {z-NlH  
} ]uJM6QuQ  
//负责部分文件的抓取 mf#fA2[  
**FileSplitterFetch.java &8juS,b  
*/ 78^Y;2 P]W  
package NetFox; 4=UI3 2v3  
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import java.io.*; -D$3!ccX  
import java.net.*; O<Jwaap  
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public class FileSplitterFetch extends Thread { dkf}),Z F  
@<
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String sURL; //File URL [6tR&D#K  
long nStartPos; //File Snippet Start Position .k p$oAL  
long nEndPos; //File Snippet End Position ^]KIgGv\  
int nThreadID; //Thread's ID 8R BDJ  
boolean bDownOver = false; //Downing is over enWF7`  
boolean bStop = false; //Stop identical yi&?d&rK  
FileAccessI fileAccessI = null; //File Access interface _y|[Z;  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Ml8E50t>;  
{ y}CkzD  
this.sURL = sURL; 3s#|Y,{?6R  
this.nStartPos = nStart; !Q[;5Lqt  
this.nEndPos = nEnd; W&WB@)ie  
nThreadID = id; m]E o(P4+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ,&-S?|  
} BllDWKb  
<r@bNx@T  
R A*(|n>  
public void run() ]cS&8{ ^2  
{ IQo]9Lx  
while(nStartPos < nEndPos && !bStop) =H L9Z  
{ iM4mkCdOO  
@F>[DW]O  
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try{ qT 5WaO)  
URL url = new URL(sURL); #}nBS-+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); J!ln=h  
httpConnection.setRequestProperty("User-Agent","NetFox"); /IrKpmbq  
String sProperty = "bytes="+nStartPos+"-"; L;L2j&i%v)  
httpConnection.setRequestProperty("RANGE",sProperty); U$MWsDn   
Utility.log(sProperty); ?<-wHj)  
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InputStream input = httpConnection.getInputStream(); L; @aE[#z  
//logResponseHead(httpConnection); F%w\D9+P  
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byte[] b = new byte[1024]; JkRGtYq  
int nRead; <m-Ni  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) hB?U5J  
{ wn&[1gBxM  
nStartPos += fileAccessI.write(b,0,nRead); kO /~i  
//if(nThreadID == 1) H0 {Mlu9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bWhJ^LD  
} s{b0#[  
>1_Dk7E0D  
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Utility.log("Thread " + nThreadID + " is over!"); :-W$PIBe  
bDownOver = true; JDIz28Ww  
//nPos = fileAccessI.write (b,0,nRead); VGq{y{(  
} pT|./ Fe  
catch(Exception e){e.printStackTrace ();} H&"_}  
} (or =f`  
} qpH j4  
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]W89.><%14  
//打印回应的头信息 n=lggBRx  
public void logResponseHead(HttpURLConnection con) c80"8r  
{ 11nO<WH  
for(int i=1;;i++) C@l +\M(  
{ Zw3hp,P]  
String header=con.getHeaderFieldKey(i); tyBg7dP  
if(header!=null) {X{01j};8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %Z-Tb
OX  
Utility.log(header+" : "+con.getHeaderField(header)); Yj|c+&Ng  
else z:@d@\$?  
break; +]aD^N9['  
} w*]_FqE  
} bQ${8ZO  
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public void splitterStop() gDUoc*+h  
{ s (l+{b &  
bStop = true; tSw~_s_V  
} >2!^ dT^D  
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}
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/* L%=BCmMx  
**FileAccess.java ?dATMmT-  
*//文件访问(定位，写) NK*:w *SOI  
package NetFox; VLl&>Pbe-  
import java.io.*; 3RY|l?n>  
J:M<9
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public class FileAccessI implements Serializable{ see'!CjVo2  
"N=&
4<]I5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 :6HiP&<  
RandomAccessFile oSavedFile; z^SN#v$  
long nPos; 'Gm!Jblo@  
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public FileAccessI() throws IOException r(`8A:#d  
{ jHUz`.8B  
this("",0); :Kt mSY  
} }J4BxBuV8  
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public FileAccessI(String sName,long nPos) throws IOException tL|L"t_5x  
{ \f<thd*bC  
oSavedFile = new RandomAccessFile(sName,"rw"); *1;L,*J"|  
this.nPos = nPos; d3\l9R
{}  
oSavedFile.seek(nPos);  t}*
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} )Uoe~\  
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public synchronized int write(byte[] b,int nStart,int nLen)
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{ ek_i{'hFd  
int n = -1; Jg?pW:}R  
try{ J>&dWKM3  
oSavedFile.write(b,nStart,nLen); u]++&~i  
n = nLen; Vo58Nz:%  
} K;(|v3g6  
catch(IOException e) p%i .(A  
{ aO;Q%]VL'  
e.printStackTrace (); lj%;d'  
} [s& y_[S  
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return n; u6CMRZ$  
} 22H=!.DJ  
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} Zzzi\5&gU  
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/* ;/]c^y  
**SiteInfoBean.java u9[w~U#  
*/ |Z +E(F  
package NetFox; \H'CFAuF  
~wQ WWRk  
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public class SiteInfoBean { }j5@\c48  
I(r5\A=  
~(L<uFU V  
private String sSiteURL; //Site's URL Fb`7aFIf  
private String sFilePath; //Saved File's Path aWi]
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private String sFileName; //Saved File's Name IBsO  
private int nSplitter; //Count of Splited Downloading File ob()+p.kK  
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public SiteInfoBean() P^W
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{//nSplitter的缺省值为5 we@En .>f  
//default value of nSplitter is 5 (Su2\x  
this("","","",5); x[,wJzp\6  
} Y3F.hk}O  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7G #e~,M5  
{ '}[L sU  
sSiteURL= sURL; c^/?VmCQ}  
sFilePath = sPath; nV6g]#~@  
sFileName = sName; g960;waz3  
this.nSplitter = nSpiltter; ri_6wbPp  
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} 'jO-e^qT  
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public String getSSiteURL() j~<iTLM  
{ iPi'5g(a   
return sSiteURL; "r(pK@h  
} Vste$V  
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public void setSSiteURL(String value) Hw-oh?=  
{ < $/Yw   
sSiteURL = value; sA7K ;J})  
} tfU3 6PR  
/3HWP`<x  
[T&y5"@  
public String getSFilePath() UyfIAC$S  
{ ~\(>m=|C:H  
return sFilePath; ~k_zMU-1  
} C4K&flk]  
9YsO+7[  
|
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public void setSFilePath(String value)
#1lS\!  
{ ;eSf4_~  
sFilePath = value; 761"S@tf$}  
} )ejqE6'[  
#]hkQo  
:JG}%  
public String getSFileName() ~8 a>D<b  
{ @G-k]IWi  
return sFileName; xRZT
 
} tqk6m# @(  
"S} hcAL/  
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public void setSFileName(String value) aD`e]K ^L  
{ zU=[Kc=$  
sFileName = value; m<HjL  
} L&k$4,Z9  
%Q4w9d  
w%u[~T7OI  
public int getNSplitter() PqeQe5  
{ 2PW3S{Dt  
return nSplitter; .aRxqFi_  
} xqZ%c/I3q  
|?b"my$g$  
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public void setNSplitter(int nCount) F4l6PGxF&\  
{ ~a|Q[tiV]  
nSplitter = nCount; !f2>6}hE  
} K#yH\fn8  
} r_CN/a  
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87*[o  
/* `Wt~6D e  
**Utility.java Z ' 96d  
*/ Q%h o[KU  
package NetFox; /{} ]Hu  
I!#^F1p1  
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public class Utility { N8Q{4c  
=!Cvu.~},  
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public Utility() `Hu;Gdj=  
{ M|u5Vs1  
?5M2DLh~  
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} \Vq;j 1  
`215Llzk;  
//线程睡眠 he6) L6T  
public static void sleep(int nSecond) Ct33S+y  
{ '0?E|B]Cp%  
try{ bHG>SW\]`?  
Thread.sleep(nSecond); ?':'zT  
} t;6/bT-  
catch(Exception e) >b
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{ c
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e.printStackTrace (); >QPS0Vx[  
} \'b-;exH  
} D(GHkS*0q  
>FhBl\oIi  
//日志  X;g|-<  
public static void log(String sMsg) v2g+oKO]  
{ Y5pNKL
 
System.err.println(sMsg); {1ceF  
} (9%%^s]uPT  
0:S)2"I58p  
j+_75t`AZ  
public static void log(int sMsg) *mtv[  
{ r4zS,J;,  
System.err.println(sMsg); GT0'bge  
} +?'acn  
} ?Fw/c0  
\`x'g)z(i  
a#$%xw  
/* 'IszS!kY  
**TestMethod.java mY9K
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*/ } 4^UVdz  
package NetFox; >{8H==P  
3 g&mND  
rKq]zHgpo  
public class TestMethod { zD|W3hL2&  
4'*K\Ul).H  
[Xg"B|FD0  
public TestMethod() ~:Nyv+g,$  
{ ///xx/weblogic60b2_win.exe 3~'F^=T.Y  
try{ XCoOs<O:@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); vZsVxx99  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); <Z[R08 k  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 4[wP$  
fileFetch.start(); :r=_\?  
} 'Mtu-\  
catch(Exception e){e.printStackTrace ();} BO|Jrr>  
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} XjNu|H/  
$x*GvI1D  
3dLz=.=)'  
public static void main(String[] args) }+1oD{  
{ x.Y,]wis  
new TestMethod(); 03T.Owd  
} $Tza<nA  
} sjGZ ,
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