http断点续传简单实现（java)

/* Y3(MKq  
**SiteFileFetch.java -OU{99$aS  
*/ j3N d4#  
package NetFox; N|>JLZ>  
import java.io.*; xfI0P0+  
import java.net.*; i4h`jFS  
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public class SiteFileFetch extends Thread { hAc|a9 o  

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SiteInfoBean siteInfoBean = null; //文件信息Bean X/vy
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long[] nStartPos; //开始位置 $\/^O94-l  
long[] nEndPos; //结束位置 5G(dvM-n  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Yo'Y-h#  
long nFileLength; //文件长度 p=E#!cn3  
boolean bFirst = true; //是否第一次取文件 P2aFn=f  
boolean bStop = false; //停止标志 k0ai#3iJ  
File tmpFile; //文件下载的临时信息 {7]maOg>7J  
DataOutputStream output; //输出到文件的输出流 pmWy:0R  
/J/V1dC}]D  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ]d7A|)q  
public SiteFileFetch(SiteInfoBean bean) throws IOException 8Yf*vp>T/x  
{ (s&]V49  
siteInfoBean = bean; qhcx\eD:?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); |&W4Dkn  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); e`LkCy[_  
if(tmpFile.exists ()) 4Otq3s34FT  
{ 4'*.3f'bp  
bFirst = false; _xm<zy{`S  
read_nPos(); Do\j_  
} .Tq8Qdl  
else MusUgBQy  
{ \9` ~9#P  
nStartPos = new long[bean.getNSplitter()]; ?a% F3B  
nEndPos = new long[bean.getNSplitter()]; cHT\sJo`l  
} y {Bajil  
 +PADy8  
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} qGMU>J.;c  
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public void run() UQ;2g\([  
{ ty"L&$bf  
//获得文件长度 {J,"iJKop  
//分割文件 ^0}wmxDq  
//实例FileSplitterFetch js Z"T  
//启动FileSplitterFetch线程 RN[x\",  
//等待子线程返回 lMu-,Z="  
try{ ,tg]Gt  
if(bFirst) $MwBt  
{ fmQif]J;;  
nFileLength = getFileSize(); FGyrDRDwC  
if(nFileLength == -1) -=gI_wLbM  
{ %W7%]Z@j  
System.err.println("File Length is not known!"); \zFCph
4  
}
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else if(nFileLength == -2) \mJR^t  
{ ~1}fL 1~5  
System.err.println("File is not access!"); h4 9q(085V  
} eWex/ m  
else fiA8W  
{ XxdD)I  
for(int i=0;i<nStartPos.length;i++) 6Y,&q|K  
{ MaY_*[  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); j nSZ@u  
} H'/V<
%  
for(int i=0;i<nEndPos.length-1;i++) /j$pV  
{ x"RF[d  
nEndPos = nStartPos[i+1]; 6|f8DX%3V  
} C R?}*  
nEndPos[nEndPos.length-1] = nFileLength; YLA(hg|  
} !^98o:"x  
} ;}U]^LT=  
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L xIKH G  
//启动子线程 biS[GyQ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @d|Sv1d%  
for(int i=0;i<nStartPos.length;i++) 0n`Temb/  
{ 5WRqeSGh  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uuF~+=.|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Vh?vD:|  
nStartPos,nEndPos,i); |zP~/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ank_;jo  
fileSplitterFetch.start(); dz/fSA  
} Cu24xP`  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m,q)lbRl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); N5=}0s]e  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^mFsrw  
nEndPos = " + nFileLength); +MaEet
 
// fileSplitterFetch[nPos.length-1].start(); GeB&S!F  
 ?f'`b<o  
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//等待子线程结束 Y:m8UnT  
//int count = 0; z2,NWmP|w  
//是否结束while循环 o~9*J)X5i  
boolean breakWhile = false; i>CR{q  
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while(!bStop) K,|3?CjS  
{ GIpYx`mHi  
write_nPos(); y&8`NS#_p?  
Utility.sleep(500); -@#],s7  
breakWhile = true; PX&}g-M9  
1(# H%  
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for(int i=0;i<nStartPos.length;i++) #`%S[)RT  
{ A=|a!N/  
if(!fileSplitterFetch.bDownOver) P(8 uL|^  
{ G,Eh8HboK  
breakWhile = false; F^!O\8PFd  
break; l?J[K  
} g +gcH  
} xele;)Y  
if(breakWhile) aCQ[Uc<B:  
break; /`aPV"$M  
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//count++; m zoH$@  
//if(count>4) =X[?
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// siteStop(); !XI9evJw  
} s!D2s2b9e  
jR\!2!  
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System.err.println("文件下载结束！"); udr|6EjD.  
} s/11TgJ  
catch(Exception e){e.printStackTrace ();} w?nSQBz$  
} w;AbJCv2  
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//获得文件长度 Bt$,=k  
public long getFileSize() _<c}iZv@  
{ .:Wp9M  
int nFileLength = -1; `<<9A\Y-f  
try{  ;ud"1wH  
URL url = new URL(siteInfoBean.getSSiteURL()); b|kL*{;
  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `uusUw-Gf  
httpConnection.setRequestProperty("User-Agent","NetFox"); z+wegF  
c>/7E-T  
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int responseCode=httpConnection.getResponseCode(); |+sAqx1IF  
if(responseCode>=400) p}gA8o  
{ B|9XqQ EI  
processErrorCode(responseCode); xmC5uT6L3M  
return -2; //-2 represent access is error N z=P1&G'  
} v<l]K$5J&  
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String sHeader; NhF"%  
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for(int i=1;;i++) if\`M'3Xx  
{ Em{;l:;(W  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 3bo [34  
//Utility.log(in.readLine()); ;KmrBNF  
sHeader=httpConnection.getHeaderFieldKey(i); wCv9VvF`  
if(sHeader!=null) *nHMQ/uf  
{ FoZI0p?L)9  
if(sHeader.equals("Content-Length")) l>s@&%;Mg  
{ |90/tNe  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /6y{?0S  
break; $1zWQJd[-  
} !SGRK01  
} x=x%F;  
else +s`cXTlFrk  
break; T4ugG?B*  
} 5K$<Ad4$b  
} L %ifl:K  
catch(IOException e){e.printStackTrace ();} ^4\0,>  
catch(Exception e){e.printStackTrace ();} e(b$L
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Utility.log(nFileLength); D88IU9V&n  
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return nFileLength; TMsCl6dB  
} tBl(E  
^x^(Rk}|  
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//保存下载信息（文件指针位置） [fvjvN`  
private void write_nPos() r5(efTgAd+  
{ s+&0Z3+  
try{ sP%b?6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); %i?v)EW  
output.writeInt(nStartPos.length); gCVOm-*:  
for(int i=0;i<nStartPos.length;i++) $cm9xW&  
{ F1M:"-bda  
// output.writeLong(nPos); pbWjTI$  
output.writeLong(fileSplitterFetch.nStartPos); jt*B0'Sa  
output.writeLong(fileSplitterFetch.nEndPos); q3K}2g  
} mC(YO y  
output.close(); [[';Hi^  
} aZtM _  
catch(IOException e){e.printStackTrace ();} Pl`Nniy  
catch(Exception e){e.printStackTrace ();} UL%a^' hR  
} {9XNh[NbP  
"}-S%v`)z  
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//读取保存的下载信息（文件指针位置） 7;Q4k"h  
private void read_nPos() fuF{8-ua  
{ (#z6w#CU(  
try{ ^7;s4q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $2}%3{<j  
int nCount = input.readInt(); EUV8H}d5  
nStartPos = new long[nCount]; x1E;dbOZ  
nEndPos = new long[nCount]; 0XqxW\8_l  
for(int i=0;i<nStartPos.length;i++) pNmWBp|ER  
{ Xi\c>eALO  
nStartPos = input.readLong(); =WZ@{z9J  
nEndPos = input.readLong(); !3DY#  
} $ O[Y  
input.close(); I-Ut7W   
}
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catch(IOException e){e.printStackTrace ();} _
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catch(Exception e){e.printStackTrace ();} $ye>;
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} x_C0=Q|K3  
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private void processErrorCode(int nErrorCode)  tL<.B  
{ w $`w
 
System.err.println("Error Code : " + nErrorCode); ^7=7V0>,:  
} -g|ji.  
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//停止文件下载 P46Q3EE  
public void siteStop() ?gjx7TQ?  
{ v#X#F9C  
bStop = true; .`v%9-5v  
for(int i=0;i<nStartPos.length;i++) ja&m-CFK  
fileSplitterFetch.splitterStop(); N0NFgW;  
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} ?0+g.,9  
} e:C4f  
//负责部分文件的抓取 nf1 `)tXG  
**FileSplitterFetch.java P$*Ngt  
*/ Sw5-^2x0'  
package NetFox; /5j5\F:33  
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import java.io.*; s2 :Vm\  
import java.net.*; x.] t
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public class FileSplitterFetch extends Thread { dB0 UZirb  
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String sURL; //File URL lNWP9?X  
long nStartPos; //File Snippet Start Position b>k2@  
long nEndPos; //File Snippet End Position C4|OsC7J  
int nThreadID; //Thread's ID {B6ywTK\`  
boolean bDownOver = false; //Downing is over ~(GNY5  
boolean bStop = false; //Stop identical x',6VTz^  
FileAccessI fileAccessI = null; //File Access interface &`tAQN*Z  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException J1~E*t^
  
{ f:J-X~T_f  
this.sURL = sURL; ~<s =yjTu+  
this.nStartPos = nStart; BNI)y@E^X  
this.nEndPos = nEnd; `r~3Pf).4  
nThreadID = id; 9 Qa_3+.B  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ZrZDyXL  
} 257$ !  
7\R"RH-  
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public void run() V{A`?Jl6{  
{ Qf}.=(  
while(nStartPos < nEndPos && !bStop) 8Gnf_lkI  
{ \[^! ys  
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try{ $60`Hh 4/  
URL url = new URL(sURL); %2g<zdab  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1<_/Qu>V  
httpConnection.setRequestProperty("User-Agent","NetFox"); AYNdV(  
String sProperty = "bytes="+nStartPos+"-"; |5X[/Q*K`W  
httpConnection.setRequestProperty("RANGE",sProperty); [;sTl~gC  
Utility.log(sProperty); < *;GJ{  
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InputStream input = httpConnection.getInputStream(); 5$cjCjY  
//logResponseHead(httpConnection); w-LENdw  
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byte[] b = new byte[1024]; /S1/ZI  
int nRead; 5s`r&2 w  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )7o?}"I  
{ h,]VWG  
nStartPos += fileAccessI.write(b,0,nRead);  [)~1Lu  
//if(nThreadID == 1) kw]?/s`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Z[ (d7  
} NVsaV;u  
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'=#fELMW  
Utility.log("Thread " + nThreadID + " is over!"); U"+W)rUd  
bDownOver = true; x|G :;{"+6  
//nPos = fileAccessI.write (b,0,nRead); C1UU v=|  
} ugE!EEy[^  
catch(Exception e){e.printStackTrace ();} ctLNzJes%  
} f% )9!qeW  
} BK6 X)1R  
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//打印回应的头信息 ov;^ev,(  
public void logResponseHead(HttpURLConnection con) +jF2{"  
{ $/;K<*O$  
for(int i=1;;i++) Yv@n$W`:  
{ m|c[C\)By  
String header=con.getHeaderFieldKey(i); vgD
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if(header!=null) ::$W .!Uv  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Y_!+Y<x7v  
Utility.log(header+" : "+con.getHeaderField(header)); PM#3N2?|E  
else "`4ky]  
break; Rb&9!z  
} g
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} ; teM^zyI  
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public void splitterStop() F4==a
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{ ThI}~$Y  
bStop = true; 9 i/ (  
} bp=r]nO  
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} 2%`= LGQC  
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/* |vl~B|",  
**FileAccess.java f5Gn!xF  
*//文件访问(定位，写) xUsL{24  
package NetFox; % ym};7'&b  
import java.io.*; 'o#oRK{#  
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public class FileAccessI implements Serializable{
2tpuv(H;  
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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 v x/YWZ  
RandomAccessFile oSavedFile; /3~L#
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long nPos; xn503,5G*7  
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public FileAccessI() throws IOException 4dPTrBQ?  
{ d9;&Y?fp  
this("",0); "YgpgW  
} kodd7 AD  
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public FileAccessI(String sName,long nPos) throws IOException 3J &Ros  
{ dVEs^ZtI  
oSavedFile = new RandomAccessFile(sName,"rw"); eDZ8F^0  
this.nPos = nPos; <a @7's  
oSavedFile.seek(nPos); V@k+RniEO  
} qfE0J;e   
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public synchronized int write(byte[] b,int nStart,int nLen) 5 k3m"*  
{ /u4RZ|&as  
int n = -1; J~]@#=,v  
try{ ?1JY6v]h4  
oSavedFile.write(b,nStart,nLen); NF6xKwRU]_  
n = nLen; {Fw"y %a^  
} Si?s69  
catch(IOException e) -GPJ,S V>  
{ Nyy&'\`!  
e.printStackTrace (); l X+~;94  
} i`r`Fj}-S-  
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4F#H$`:[  
return n; 
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} 9Sxr9FLW~  
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} _90D4kGU  
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/* (is',4^b  
**SiteInfoBean.java [StnKQ?"wz  
*/ HdqB B
  
package NetFox; Bc"MOSV0  
qsep9z.  
VRQ`-#  
public class SiteInfoBean { c.IUqin  
@9HRGxJ=}  
: "|/  
private String sSiteURL; //Site's URL Ul_Zn  
private String sFilePath; //Saved File's Path OlRXgJ  
private String sFileName; //Saved File's Name y%i9 b&gDd  
private int nSplitter; //Count of Splited Downloading File Qq`S=:}~x  
}h45j84)  
<WZ{<'ajI  
public SiteInfoBean() 2lpPN[~d  
{//nSplitter的缺省值为5 ))|d~m  
//default value of nSplitter is 5 T:@6(_Z  
this("","","",5); xX%ppD7  
} vF$( Y/  
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-K=.A*}  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \DQu!l@1U  
{ < bC'.m  
sSiteURL= sURL; {wz)^A sy  
sFilePath = sPath; ,^?g\&f(  
sFileName = sName; -a)1L'R  
this.nSplitter = nSpiltter; A r]*?:4y[  
>fXtu:C-!J  
<!Cjq,Sk7  
} h$'6."I  
6U*CR=4  
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public String getSSiteURL() %(W&
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{ I2$DlEke  
return sSiteURL; \ T#|<=  
} K`Kv.4  
vYV!8o.I  
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public void setSSiteURL(String value) Ux=~-}<-w  
{ #("M4}~  
sSiteURL = value; ,yGbMOV  
} +s}&'V^  
q!:dZES  
[n[dr@J7v  
public String getSFilePath() (uvQ/!  
{ }( F:U#  
return sFilePath; 9Y.(xp &vw  
} p [C 9g  
0 MK}  
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public void setSFilePath(String value)  W94:%  
{ %jjPs.  
sFilePath = value; ^\ x'4!W  
} fY&TI}Y  
#!F>cez  
"++\6H<  
public String getSFileName() w&L~+Z<  
{ O.B9w+G=  
return sFileName; 2/4zg  
} t<` As6}  
Nj4CkMM[3  
v ^h:E  
public void setSFileName(String value) g9" wX?*  
{ F9o7=5WAb  
sFileName = value; / rc[HbNg.  
} }dzdx"  
@.-S(MNR  
* |,N/e  
public int getNSplitter() ^yPZ$Q  
{ !{^kH;
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return nSplitter; IADHe\.  
} 3T
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;|vP|X
i  
3Q
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public void setNSplitter(int nCount) P'qBqx[  
{ L6_%SGY_iE  
nSplitter = nCount; s<{ Hu0K$  
} V gMgeja  
} ]_h3  
m:h6J''<Z*  
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/* %!nI]|  
**Utility.java !vf:mMo  
*/ 8+[Vo_]  
package NetFox; %N-aLw\  
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public class Utility { )9`HO?   
$b|LZE\bU.  
\~*<[.8~  
public Utility() <{cY2cx~3  
{ 6 ^3RfF^W  
3
2 i6j  
7{}E{/  
} Xeq9Vs zg  
=T9h7c R  
//线程睡眠 j<~Wp$\i7>  
public static void sleep(int nSecond) YjDQ`f/  
{ gFp3=s0~  
try{ {ze69 h  
Thread.sleep(nSecond); a5#G48'X  
} hP+4{F*}-  
catch(Exception e) |s! _;6  
{ ^Q`5+  
e.printStackTrace (); aPelt`  
} gw"cX
ny  
} Cy?]o?_?  
1]:,Xa+|S  
//日志 {KHI(*r;  
public static void log(String sMsg) M3-lL;!n  
{ /iO"4%v  
System.err.println(sMsg); o5s6$\"  
} vm|u~Yd,s  
+H3~Infr4f  
`;}`>!8j  
public static void log(int sMsg) A:(|"<lA  
{ Vbv^@Kp  
System.err.println(sMsg); 89:nF#  
} cIwX sx  
} w317]-n  
rQ*w3F?:  
iXm&\.%  
/* 68z#9}  
**TestMethod.java U*a#{C7"  
*/ {%3WHGr%L  
package NetFox; "y
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 <)TIj6  
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public class TestMethod { s8,YQ5-  
o)5zvnu7  
twr{jdY9  
public TestMethod() /^xv1F{  
{ ///xx/weblogic60b2_win.exe ~JT2el2W7p  
try{ I]eeV+U8W  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); IaeO0\ 4E  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); t[q2W"#.  
SiteFileFetch fileFetch = new SiteFileFetch(bean); y7UU'k`  
fileFetch.start(); 8j>V?'Szk  
} R7Qj<,  
catch(Exception e){e.printStackTrace ();} ~}b0zL  
n3$=&  
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} }BM`4/  
VvW4!1Dl  
\YzKEYx+  
public static void main(String[] args) : 2%eh  
{ bQ>wyA+G&E  
new TestMethod(); %EU_OS(u.{  
} F8?,}5j  
} f0g/`j@Up  
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