http断点续传简单实现（java)

/* h~(D@/tB  
**SiteFileFetch.java Vg>( Y,  
*/ #Ap;_XcKw  
package NetFox; K"0PTWt  
import java.io.*; ph_4q@  
import java.net.*; KrXdnY8  
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public class SiteFileFetch extends Thread { Qhw^S*  
/MF!GM  
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SiteInfoBean siteInfoBean = null; //文件信息Bean PZm:T+5H  
long[] nStartPos; //开始位置 Da v PYg  
long[] nEndPos; //结束位置 V%_4%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 jC3Vbm&ZZ  
long nFileLength; //文件长度 !p[9{U->o;  
boolean bFirst = true; //是否第一次取文件 =r.mlc``W  
boolean bStop = false; //停止标志 `c69?/5  
File tmpFile; //文件下载的临时信息 E%'~'[Q
 
DataOutputStream output; //输出到文件的输出流 0V{(Ru.O  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） S<L.c  
public SiteFileFetch(SiteInfoBean bean) throws IOException tU^kQR!  
{
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siteInfoBean = bean; 8NU`^L:1  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #CnHf  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 8srBHslI  
if(tmpFile.exists ()) g >'p>}t  
{ Bcjx>#3?L  
bFirst = false; 90# ;?#  
read_nPos(); LT~YFS  
} _6k*'aT~FK  
else `g_"GE  
{ c=[O `/f  
nStartPos = new long[bean.getNSplitter()]; {66fG53x  
nEndPos = new long[bean.getNSplitter()]; N,J9Wu ZJ\  
} ;),BW
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} i,nm`Z>u  
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public void run() a6h>=uT [  
{ 97,rE$bC  
//获得文件长度 <|*'O5B  
//分割文件 lg}HGG  
//实例FileSplitterFetch |T4kqW{  
//启动FileSplitterFetch线程 gUAxyV  
//等待子线程返回 tURc bwV  
try{ jhGlG-^  
if(bFirst) {3Y )rY!z  
{ 1 Vy,&[c~"  
nFileLength = getFileSize(); '>k{tPi.  
if(nFileLength == -1) 2T)sXBu  
{ zD)pF1,7:8  
System.err.println("File Length is not known!"); /:\3 \{?0m  
} OI0B:()  
else if(nFileLength == -2) vZ#!uU^a:  
{ -.<k~71  
System.err.println("File is not access!"); $>R(W=Q  
} }K(o9$V ^!  
else ` r']^ ,  
{ `aqrSH5^h  
for(int i=0;i<nStartPos.length;i++) GOSI3RRn  
{ 8yWoPm<A  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Qpt&3_   
} +q''y  
for(int i=0;i<nEndPos.length-1;i++) r,N[)@  
{ 3"UsZyN:  
nEndPos = nStartPos[i+1]; ^# A.@  
} (X6sSO  
nEndPos[nEndPos.length-1] = nFileLength; n^hocGH*  
} (vJ2z =z  
} X['2b78k  
]Y.deVw3i  
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//启动子线程 CiL94Nkd9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; S^f:`9ab9  
for(int i=0;i<nStartPos.length;i++) a}d6o;li  
{ m_!U}!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0ZC,BS`D^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), p8,0lo  
nStartPos,nEndPos,i); W3Ulewa  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]v5-~E!  
fileSplitterFetch.start(); BN@,/m9OQ%  
} Sd:.KRTu.  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), q2_`v5t  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,vG<*|pn  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", @ERu>nSP  
nEndPos = " + nFileLength); b0a}ME&1  
// fileSplitterFetch[nPos.length-1].start(); EX?h0Uy  
}.:d#]g8  
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//等待子线程结束 djT. 1(  
//int count = 0; zH'2s-.bi  
//是否结束while循环 oA~4p(  
boolean breakWhile = false; y,<$X.>QO|  
[U_[</L7  
4w{-'M.B  
while(!bStop) 98*x 'Wp  
{ wq4nMY:#  
write_nPos(); 00M`%c/  
Utility.sleep(500); 4^Ow^7N?  
breakWhile = true; D{AFL.r{  
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/#yA%0=w  
for(int i=0;i<nStartPos.length;i++) :HW>9nD
.  
{ FD6
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if(!fileSplitterFetch.bDownOver) ;aK.%-s-Z  
{ `)[dVfxA  
breakWhile = false; -3mgza  
break; /84bv=  
} 7C5pAb:  
} 3cu9[~K  
if(breakWhile) h#{T}[  
break; m4gU*?  
<F=Dj*]  
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//count++; } gkP  
//if(count>4) >I-g[*  
// siteStop(); wZv-b*4  
} lcig7%  
6+8mV8{-8  
>Zdi5') 5  
System.err.println("文件下载结束！"); *mV&K\_  
} /p$=Cg[K  
catch(Exception e){e.printStackTrace ();} bm}+}CJ@#0  
} _j 5N=I{U  
.&chdVcxyS  
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//获得文件长度 qG^_c;l6
a  
public long getFileSize() cqk]NL`'  
{ Y*\6o7  
int nFileLength = -1; cDO:'-  
try{ ]-KV0H  
URL url = new URL(siteInfoBean.getSSiteURL()); ! o^Ic`FhS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +\U]p_Fo3  
httpConnection.setRequestProperty("User-Agent","NetFox"); M@~o6^  
P/`m3aSzX.  
i7f%^7!  
int responseCode=httpConnection.getResponseCode(); >i`8R  
if(responseCode>=400) l% |cB93  
{ 1uC;$Aj6:  
processErrorCode(responseCode); 8{@`kyy|  
return -2; //-2 represent access is error q\U4n[Zk  
} <p)Z/  
|>@-grs  
7&px+155  
String sHeader; p6[#f96^u  
5&G 5eA  
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for(int i=1;;i++) 2)?  
{ \2Xx%SX  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); lY->ucS %P  
//Utility.log(in.readLine()); 55,=[  
sHeader=httpConnection.getHeaderFieldKey(i); Lb^(E-  
if(sHeader!=null) u x#.:C|  
{ f^u^-l  
if(sHeader.equals("Content-Length")) jPpRsw>  
{ E\_
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); EFwL.'Fh  
break; RZe#|k+ 8  
} vi<X3G6Xh  
} 4XD)E&  
else H):-!?:  
break; *i%.{ YH  
} =tNzGaWJ  
} =Iy/cHK  
catch(IOException e){e.printStackTrace ();} 7:h<`_HT(X  
catch(Exception e){e.printStackTrace ();} ^~, ndH{  
 :4{Qh  
XL&hs+Y  
Utility.log(nFileLength); 2q/nAQ+  
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return nFileLength; tnN'V  
} )F
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2|$lk8/,  
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//保存下载信息（文件指针位置） z2.*#xTZn  
private void write_nPos() Uld_X\;Q4  
{ ([[)Ub$U  
try{ ^g70AqUc  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Q6eN+i2 ;  
output.writeInt(nStartPos.length); Y:rJK|m  
for(int i=0;i<nStartPos.length;i++) c%jsu"  
{ g)X7FxS,z  
// output.writeLong(nPos); pn|p
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output.writeLong(fileSplitterFetch.nStartPos); Sy4 mZ}:  
output.writeLong(fileSplitterFetch.nEndPos); ~."!l'a  
} T=^jCH &  
output.close(); nG!&u1*  
} k\nH&nb  
catch(IOException e){e.printStackTrace ();} >'eB2  
catch(Exception e){e.printStackTrace ();} =d}gv6v2S  
} P8"6"}B;T  
1V-=$Q3 V7  
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//读取保存的下载信息（文件指针位置） MRjH40"2  
private void read_nPos() w'!ECm>*`  
{ .4H_Zt[2  
try{ fS5GIC
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); +ylxez
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int nCount = input.readInt(); N[0 xqQ  
nStartPos = new long[nCount]; N$C{f;xV  
nEndPos = new long[nCount]; qUifw @  
for(int i=0;i<nStartPos.length;i++) &/
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{ ".Lhte R?  
nStartPos = input.readLong(); j#7wyi5q  
nEndPos = input.readLong(); D/gd  
} f-vZ2+HP  
input.close(); `l+ >iM  
} \d `dV0X  
catch(IOException e){e.printStackTrace ();} l.XknF  
catch(Exception e){e.printStackTrace ();} o9_(DJ<{  
} M4zX*&w.T  
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private void processErrorCode(int nErrorCode) kyy0&L  
{ =$^Wkau  
System.err.println("Error Code : " + nErrorCode); {z.[tvE8h  
} >r;ABz/  
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//停止文件下载 qgwv=5|  
public void siteStop() o}WB(WsG  
{ ^zvA?'s  
bStop = true; jz|Wj  
for(int i=0;i<nStartPos.length;i++) AeNyZ[40T  
fileSplitterFetch.splitterStop(); C>.]Bvg  
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>v^2^$^u  
} ."~7 \E> t  
} ExNj|*  
//负责部分文件的抓取 cxtLy&C  
**FileSplitterFetch.java BengRG[  
*/ ?R|fS*e2EB  
package NetFox; JK@izI  
:SpG&\+  
S% JNxT7'  
import java.io.*; 2uvQf&,  
import java.net.*; ^m6k@VM  
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public class FileSplitterFetch extends Thread { Jo6~r-  
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String sURL; //File URL 3R)cbwL  
long nStartPos; //File Snippet Start Position .\z|Fr  
long nEndPos; //File Snippet End Position zznPD%#Sc  
int nThreadID; //Thread's ID J{nyo1A  
boolean bDownOver = false; //Downing is over +zFV~]b  
boolean bStop = false; //Stop identical pRQfx^On  
FileAccessI fileAccessI = null; //File Access interface *kX3sG$8  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException  At`1)  
{ ?=;e.qK=71  
this.sURL = sURL; K#9(|2J%  
this.nStartPos = nStart;
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this.nEndPos = nEnd; 2a._?(k_y  
nThreadID = id; XEf&Yd  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 aBqe+FXp4  
} {V]Qwz)1  
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public void run() F:*[  
{ T3u5al  
while(nStartPos < nEndPos && !bStop)
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{ }#\;np  
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try{ Z30z<d,j  
URL url = new URL(sURL); /XWPN(JC?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); SQ~N X)  
httpConnection.setRequestProperty("User-Agent","NetFox"); C0t+Q  
String sProperty = "bytes="+nStartPos+"-"; *f0.=?  
httpConnection.setRequestProperty("RANGE",sProperty); v GR \GFm  
Utility.log(sProperty); E]u'MX  

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InputStream input = httpConnection.getInputStream(); )
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//logResponseHead(httpConnection); /c_kj2& ]9  
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byte[] b = new byte[1024]; UALg!M#  
int nRead; Ry8WNVO}R  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) DmXDg7y7s  
{ r3c\;Ra7  
nStartPos += fileAccessI.write(b,0,nRead); MUCJ/GF*  
//if(nThreadID == 1) 7+D'W7Yx  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); aCUV[CPw  
} h-2E9Z  
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Utility.log("Thread " + nThreadID + " is over!"); +QXYU8bYZ  
bDownOver = true; qa0JQ_?o]  
//nPos = fileAccessI.write (b,0,nRead); 9p[W :)P4d  
} WB=<W#?w7%  
catch(Exception e){e.printStackTrace ();} [KimY  
} *xv/b=  
} XD+cs.{5  
$@u^Jt, ?  
6XOpB^@  
//打印回应的头信息 +}(B856+  
public void logResponseHead(HttpURLConnection con) 3Q*RR"3  
{ l9ifUhe  
for(int i=1;;i++) +4:+qGAJ{  
{ LKqog%,c  
String header=con.getHeaderFieldKey(i); }lNufu  
if(header!=null) 4M0
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); #a'x)$2;R|  
Utility.log(header+" : "+con.getHeaderField(header)); 2uc
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else #hE3~+i  
break; V&,<,iNN  
}
:WfB!4%!  
} e@2Vn? 5  
]!tYrSM!  
@rK>yPhf  
public void splitterStop() O 44IH`SI  
{ X,!OWz:[  
bStop = true; L1Cn  
} ^pQ;0[9Y0  
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} qT<qu(V:  

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/* WlQ&Yau  
**FileAccess.java xwH|ryfs,Z  
*//文件访问(定位，写) VrGb;L'[  
package NetFox; #g`cih=QL  
import java.io.*; oIL+@}u7  
U*R~w5W.[  
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public class FileAccessI implements Serializable{ iJaNP%N  
!,JT91  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @#--dOWYR  
RandomAccessFile oSavedFile; ^a#&wW  
long nPos; p:Ld)U*  
q(ET)xCeD  
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public FileAccessI() throws IOException zm3MOH^a  
{ f_P+qm  
this("",0); -IsdU7}  
} 7F9g:r/^  
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public FileAccessI(String sName,long nPos) throws IOException I^\bS  
{ .6Lhy3x  
oSavedFile = new RandomAccessFile(sName,"rw"); |XdrO
  
this.nPos = nPos; 0)Xue9A
S  
oSavedFile.seek(nPos); ^s2-jkK  
} `# M.t);^  
1>@|  
[qD<U%Hi  
public synchronized int write(byte[] b,int nStart,int nLen) 4C9"Q,o%&  
{ |&RX>UW$W  
int n = -1; 8YLZ)k'  
try{ w@$o  
oSavedFile.write(b,nStart,nLen); %b%<g%@i  
n = nLen; |VR5Q(d  
} =qR7-Q8B  
catch(IOException e) k+GK1Yl  
{ AXv;r<  
e.printStackTrace (); ?gMrcc/{  
} D&6Qk&>  
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return n; v4a4*rBI"  
} e}yu<~v_  
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} Y+`-~ 88  
*P\_:>bV(  
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/* DCzPm/#b  
**SiteInfoBean.java +C;#Qf  
*/ {1U*:@j  
package NetFox; glX2L~  
+|)#yE$aMh  
4m(>"dHP  
public class SiteInfoBean { 3[i!2iL.  
?BvI/H5d  
~dr1Qi#j?  
private String sSiteURL; //Site's URL E0A|+P '?  
private String sFilePath; //Saved File's Path Vd>.fb\U2  
private String sFileName; //Saved File's Name +9F#~{v`4a  
private int nSplitter; //Count of Splited Downloading File 4_0/]:~5  
TaO;r=2  
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public SiteInfoBean() J9c3d~YW  
{//nSplitter的缺省值为5 {,2_K6
#  
//default value of nSplitter is 5 |ylTy B
 
this("","","",5); 4 Wd5Goe:  
} LA%al @  
^&/&I9z  
CvWEXY_P2  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) XJ/kB8  
{ zP'pfBgbJW  
sSiteURL= sURL; lBZ*G  
sFilePath = sPath; yzR=:0J  
sFileName = sName; 4lUE(#kUM  
this.nSplitter = nSpiltter; Cwf$`?|W  
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} wggHUr(g,  
cB=u;$k@*  
n$Fm~iPo,  
public String getSSiteURL() 8'Bl=C|0X  
{ ^Es)?>eah  
return sSiteURL; c} ET#2,  
} iB`]Z@ZC  
(w B[ ]O$@  
x%ag.g2I  
public void setSSiteURL(String value) o xu9
v/  
{ =,G(1#  
sSiteURL = value; rL3Vogw'e  
} DC7}Xly(  
\9zC?Cw  
:.df(1(RL  
public String getSFilePath() (k.7q~:  
{ iquGLwJ  
return sFilePath; yS3s5C{C  
} =Fl4tY#X  
(HKm2JuFG  
G
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public void setSFilePath(String value) 7N=VVD~!b  
{ =@XR$Uud6  
sFilePath = value; 0\*<k`dY  
} mLA$F4/K  
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gg_(%.>  
public String getSFileName() $Ws2g*i  
{ 4jro4B`  
return sFileName; :''0z  
} W78-'c  
L$Z_j()2  
HbVm O]#$D  
public void setSFileName(String value) 7}.(EZ0  
{ *.l=>#qF  
sFileName = value; (@
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} z# B) b5  
4q8%!\A+  
3$;v# P$%N  
public int getNSplitter() dUSuhT  
{ R.;59s  
return nSplitter; epm|pA*  
} y&]D2"I  
>UH=]$0N  
,1L^#?Q~  
public void setNSplitter(int nCount) !!%F$qUd\  
{ ABGL9;.8  
nSplitter = nCount;  sOmYQ{R  
} &>{L"{  
} XW:(FzF  
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VEm[F/'  
/* !<ucwWY,  
**Utility.java b\mN^P~>A  
*/ ly+7klQ;.  
package NetFox; 0@;E8^pa  
,0xN#&?Ohh  
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public class Utility { *L_wRhhk  
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public Utility() HtlXbzN%)  
{ ><HXd+- sd  
nor`w,2VF  
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} ;$]R#1i44  
Emo]I[<&q  
//线程睡眠 EIAT*l:NW  
public static void sleep(int nSecond) k9 E?5  
{ 2J$Uz,@  
try{ V-57BKeDz  
Thread.sleep(nSecond); %' Fc%3  
}
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catch(Exception e) =n!8>8d  
{ APya&TG  
e.printStackTrace (); p/:L;5F  
} @EvnV.  
} =`")\?z}  
$!t!=  
//日志 [z?XVl<  
public static void log(String sMsg) R?k1)n   
{ <GC:aG  
System.err.println(sMsg); M II]sF  
} hH~Z hB  
azSS:=A  
rmhB!Lo  
public static void log(int sMsg) Wo%&,>]<H  
{ : f
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System.err.println(sMsg); ^,50]uX_  
} DvGtO)5._  
} |Ia46YS  
2w%1\TcB$  
_\"?:~rUN  
/* $W)FpN;CW/  
**TestMethod.java [}Nfs3IlBw  
*/ *+iWB_  
package NetFox; ky*-_  
E+_}8J .  
G$q=WM!%#s  
public class TestMethod { 5p750`n  
b'G4KNW  
m{' q(w}  
public TestMethod() jtA Yp3M-$  
{ ///xx/weblogic60b2_win.exe 1}N5WBp  
try{ ?x:\RNB/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }[1I_)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); tTY(I1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 4Hu.o7  
fileFetch.start(); +Q{jV^IT9  
} UO</4WJ  
catch(Exception e){e.printStackTrace ();} .NabK  
1=s%.0  
atYm.qb  
} R+5x:mpHy  
^ c:(HUo#  
K }r%OOn0  
public static void main(String[] args) o rEo$e<  
{ >XA#/K  
new TestMethod(); RS$e^_W  
} .L8S_Mz  
} a7ZPV1k  
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