http断点续传简单实现（java)

/* v>y8s&/  
**SiteFileFetch.java 3w^J"O/T  
*/ Z!RRe]"y  
package NetFox; ghobu}wuF  
import java.io.*; )_Xxk_  
import java.net.*; wO_pcNYZ8  
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public class SiteFileFetch extends Thread { t=W$'*P0}  
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SiteInfoBean siteInfoBean = null; //文件信息Bean g"Q}h  
long[] nStartPos; //开始位置 g=oeS%>E  
long[] nEndPos; //结束位置 {
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 DNm7z[t{  
long nFileLength; //文件长度 C?/r}ly<\  
boolean bFirst = true; //是否第一次取文件 %KJhtd"q  
boolean bStop = false; //停止标志 m
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File tmpFile; //文件下载的临时信息 rtYb"-&  
DataOutputStream output; //输出到文件的输出流 K.#,O+-Kg`  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） liCCc;&B;  
public SiteFileFetch(SiteInfoBean bean) throws IOException @ yg|OA}  
{ c_-" Qo  
siteInfoBean = bean; 1%/ NL?8#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); XC7Ty'#"KX  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 6_9:Eb=^v!  
if(tmpFile.exists ()) O{")i;v@  
{ "9U+h2#]  
bFirst = false; Y>78h2AU  
read_nPos(); x  tYV"  
} Z/
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else i)@U.-*5m  
{ f74%YY  
nStartPos = new long[bean.getNSplitter()]; MAwC\7n+X  
nEndPos = new long[bean.getNSplitter()]; c#\ah}]Vo  
} "UhK]i*@l  

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{.aK{ V  
} [D<RV3x9  
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public void run() (<]\,pP0_  
{ _XY`UZ  
//获得文件长度 HsjELbH  
//分割文件 ]=?X*,'  
//实例FileSplitterFetch PmPyb>HK=P  
//启动FileSplitterFetch线程 Qm35{^p+  
//等待子线程返回 #sz]PZ\  
try{ pW*{Mx  
if(bFirst) ]^yV`Z8  
{ 3:]{(@J  
nFileLength = getFileSize(); 95.qAFB1  
if(nFileLength == -1) pgz:F#>  
{ 45Nv_4s  
System.err.println("File Length is not known!"); p|&ZJ@3  
} y'J:?!S,Yu  
else if(nFileLength == -2) rQu  
{ 1&X}1  
System.err.println("File is not access!"); N`,7FI}  
} 936Ff*%(l  
else d'N(w7-Y  
{ Gt^|+[gD  
for(int i=0;i<nStartPos.length;i++) .DgoOo%?"  
{ Nk lz_
]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ! 6p>P4TT  
} CTh1+&Pa  
for(int i=0;i<nEndPos.length-1;i++) & cM u/}  
{ 0OleO9Ua  
nEndPos = nStartPos[i+1]; WW@JVZxK  
} .+{nA}Bc  
nEndPos[nEndPos.length-1] = nFileLength; =8$|_  
} Zvd ;KGO(a  
} @Ufa-h5"(  
e+NWmu{<_  
:.C+?$iuX  
//启动子线程 @IEI%vH  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; R(M}0JRm  
for(int i=0;i<nStartPos.length;i++) ??|d=4g\  
{ AC9{*K[  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4^ c!_K&&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Jn@Z8%B@Z  
nStartPos,nEndPos,i); l%^h2 o  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <'r0r/0g?  
fileSplitterFetch.start(); ^
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} j`>?"1e@x  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8B}'\e4i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 17e=GL  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", e{v,x1Y_z(  
nEndPos = " + nFileLength); 4 hL`=[AB  
// fileSplitterFetch[nPos.length-1].start(); _L$)2sl1R  
~Y\QGuT  
$-m@KB  
//等待子线程结束 \9046An  
//int count = 0; /)sDnJ1r  
//是否结束while循环 PPUEkvH W  
boolean breakWhile = false; %GM>u2baw  
*6NO-T; -  
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while(!bStop) y:qx5Mi  
{ \eEds:Hg  
write_nPos(); VMaS;)0f@  
Utility.sleep(500); \M+MDT&  
breakWhile = true; smQ4CLJ  
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J cP~-cp  
for(int i=0;i<nStartPos.length;i++) ||R0U@F,  
{ #]@9qPyn  
if(!fileSplitterFetch.bDownOver) b2G2cL-(  
{ k69kv9v@J  
breakWhile = false; ' Q\@19  
break; ldK>HxM%Z  
} A_@I_V$  
} GaHA%  
if(breakWhile) {nTG~d  
break; !IN@i:m  
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//count++; Z*h43  
//if(count>4) +a #lofhv  
// siteStop(); j]>=1Rd0b(  
} Bw6L;Vu  
\WcB9  
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System.err.println("文件下载结束！"); Yhe+u\vGs\  
} %Mh Q  
catch(Exception e){e.printStackTrace ();} #^Ys{  
} `-o5&>'nf  
,6DD=w0r  
R'L?Xn}3  
//获得文件长度 vmvFBzLR  
public long getFileSize() !I~C0u  
{ V`by*s  
int nFileLength = -1; Vd21,~^>g  
try{ <>]1Y$^Y
 
URL url = new URL(siteInfoBean.getSSiteURL()); te)n{K",  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '[Xl>
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httpConnection.setRequestProperty("User-Agent","NetFox"); wrabyRjK  
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int responseCode=httpConnection.getResponseCode(); Vg{Zv4+t  
if(responseCode>=400) vu<#wW*9  
{ eH
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processErrorCode(responseCode); iTu0T!4F  
return -2; //-2 represent access is error 7D   
} l0Y?v 4  
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String sHeader; H'Ln P>@n#  
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for(int i=1;;i++) BRa{\R^I  
{ L%XXf3;c  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -TTs.O8P|<  
//Utility.log(in.readLine()); {OCJ(^8i  
sHeader=httpConnection.getHeaderFieldKey(i); vr4O8#  
if(sHeader!=null) doM?8C#`  
{ ddoFaQ8  
if(sHeader.equals("Content-Length")) 84^[/d;!  
{ p,;mYms  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); CU$)QH{  
break; 6{.J:S9n   
} B)6#Lp3  
} s/t
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else m2O&2[g  
break; 3cixQzb}u  
} 5ITq?%{M  
} Yb6q))Y  
catch(IOException e){e.printStackTrace ();} |1Hc&  
catch(Exception e){e.printStackTrace ();} ! Mo`^t  
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Utility.log(nFileLength); 6,+nRiZ  
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return nFileLength; @5E,:)T*wR  
} '$[Di'*;  
J633uH}}  
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//保存下载信息（文件指针位置） 9Ejyg*  
private void write_nPos() "Pj}E=!k  
{ wa ky<w,  
try{ 8TPN#"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); F
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output.writeInt(nStartPos.length);  D:JS)+]  
for(int i=0;i<nStartPos.length;i++) Y(r@v  
{ +EkW>$  
// output.writeLong(nPos); ]JMl|e  
output.writeLong(fileSplitterFetch.nStartPos); 1bSD,;$sQ  
output.writeLong(fileSplitterFetch.nEndPos); OipqoI2  
} "U8S81'  
output.close(); K9|7dvzC:  
} Im)EDTm$  
catch(IOException e){e.printStackTrace ();} < kP+eD  
catch(Exception e){e.printStackTrace ();} mQr0sI,o]  
} nIBFk?)6  
@;Y~frT  
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//读取保存的下载信息（文件指针位置） A,#2^dR  
private void read_nPos() ~xDw*AC-  
{ 61@EDIYPc  
try{ Lh ap4:  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); JE;+T[I  
int nCount = input.readInt(); F,T~\gO5,  
nStartPos = new long[nCount]; f$F*3  
nEndPos = new long[nCount]; &tE.6^F
 
for(int i=0;i<nStartPos.length;i++) LM"y\q ]  
{ Yc;ec9~  
nStartPos = input.readLong(); z-,VnhLx  
nEndPos = input.readLong(); |W7rr1]~S  
} GwLFL.Ke  
input.close(); p]ivf  
} ^Z}Ob= .G  
catch(IOException e){e.printStackTrace ();} RU&_j*U  
catch(Exception e){e.printStackTrace ();} D7?C  
} r;gP}H ?  
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L1#Ij#  
private void processErrorCode(int nErrorCode) AK-}V4C/A  
{ g/Wh,f3  
System.err.println("Error Code : " + nErrorCode); 0KvVw rWJ  
} Q8qz*v]{  
^b-18 ~s  
^^Jnv{)  
//停止文件下载 <@uOCRbV  
public void siteStop() }Je>;{&%  
{ #A<P6zJXR  
bStop = true; pq!%?m]  
for(int i=0;i<nStartPos.length;i++) RBGX_v?  
fileSplitterFetch.splitterStop(); 5VE2@Fn}  
- u3e5gW  
;4#D,zlO^  
} =A!S/;z>  
} *"{&FEV  
//负责部分文件的抓取 O'DW5hBL0  
**FileSplitterFetch.java C"w {\ &R  
*/ o>lmst%<  
package NetFox; \%A%s*1  
l{WjDed  
&KC!*}<tx  
import java.io.*; \nvAa_,  
import java.net.*; !<\Br  
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public class FileSplitterFetch extends Thread { Y}STF  
!1sU>Xb4J  
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String sURL; //File URL k(s;,B\  
long nStartPos; //File Snippet Start Position >cR)?P/o  
long nEndPos; //File Snippet End Position 7C,T&g 1:  
int nThreadID; //Thread's ID C!x/ ^gw  
boolean bDownOver = false; //Downing is over 4? (W%?  
boolean bStop = false; //Stop identical <,1fkq>,  
FileAccessI fileAccessI = null; //File Access interface F[`ZqW  
lj
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F # YPOH  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _}Ps(_5D  
{ {rH9grb  
this.sURL = sURL; yJ2B3i@T4  
this.nStartPos = nStart; Q9?t[ir  
this.nEndPos = nEnd; ^ @=^;nB  
nThreadID = id; 6XV<? 9q  
fileAccessI = new FileAccessI(sName,nStartPos);//定位
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} rAq
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public void run() `)>7)={  
{ +C{p%`<  
while(nStartPos < nEndPos && !bStop) 1(dj[3Mt  
{ %@J1]E;  
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try{ =[tSd)D,y  
URL url = new URL(sURL); o4^Fo p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =_TaA(79  
httpConnection.setRequestProperty("User-Agent","NetFox"); j2n,f7hl.  
String sProperty = "bytes="+nStartPos+"-"; m~l F`?  
httpConnection.setRequestProperty("RANGE",sProperty); 'ktHPn ,K  
Utility.log(sProperty); rP=sG;d  
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InputStream input = httpConnection.getInputStream(); j .A6S`  
//logResponseHead(httpConnection); RMYP"  
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byte[] b = new byte[1024]; {{yt*7k{  
int nRead; ug&[ IL~lc  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) j5 wRGn3  
{ jFG0`n}I  
nStartPos += fileAccessI.write(b,0,nRead); F phDF  
//if(nThreadID == 1) ]gb=  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9l/EjF^  
} "E=j|q  
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Utility.log("Thread " + nThreadID + " is over!"); ]
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bDownOver = true; v6a]1B
  
//nPos = fileAccessI.write (b,0,nRead); ^(x^6d  
} Bstk{&ew  
catch(Exception e){e.printStackTrace ();} jdqj=Yc  
} <&!]K?Q9i  
} SpTdj^]4>  
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M
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//打印回应的头信息 =d;Vk  
public void logResponseHead(HttpURLConnection con) p#8
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{ TQ :/RT  
for(int i=1;;i++) < a rZbM  
{ dx_6X!=.J  
String header=con.getHeaderFieldKey(i); Zy"=y+e!E;  
if(header!=null) USML~]G z  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); o,Z{ w"  
Utility.log(header+" : "+con.getHeaderField(header)); ;-mdi/*g  
else h+7>#*DH  
break; rx~[Zs+*  
} tOdT[&  
} p QE)p  
/ci]}`'ws  
(g8*d^u#PO  
public void splitterStop() mPZGA\  
{ .q`{Dgc~  
bStop = true; V-O(U*]  
} jB$SUO`*  
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#~ v4caNx  
} 2i=H"('G)+  
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/* aC=['a>)  
**FileAccess.java Z)< wv&K  
*//文件访问(定位，写) Ibr%d2yS=  
package NetFox; 4n( E;!s  
import java.io.*; J
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'%iPVHK7  
(
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public class FileAccessI implements Serializable{ ;6;H*Y0,|E  
'"YYj$> '  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @uleyB  
RandomAccessFile oSavedFile; >wON\N0V_  
long nPos; 8QgA@y"  
a=]Wzlz
 
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public FileAccessI() throws IOException ^JeMuU  
{ GlYly5F  
this("",0); JNU/`JN9f  
} /MTf0^9  
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public FileAccessI(String sName,long nPos) throws IOException %CH6lY=lI  
{ 6F0(aGs  
oSavedFile = new RandomAccessFile(sName,"rw"); @"87F{!  
this.nPos = nPos; .J.vC1 4gi  
oSavedFile.seek(nPos); S'i;xL>  
} Ww9;
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public synchronized int write(byte[] b,int nStart,int nLen) v"lf-c  
{ YcM;S  
int n = -1; ur%$aX)  
try{ hSV@TL  
oSavedFile.write(b,nStart,nLen); F@W*\3)  
n = nLen; khX|"d360  
} F1W+o?B  
catch(IOException e) F9o6V|v  
{ M@7Xp)S"  
e.printStackTrace (); GrI&?=S^  
} 7Ua7A  
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return n; .Ao0;:;(2-  
} QApyP CH  
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} :=.*I  
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/* k=n "+  
**SiteInfoBean.java 00<{:  
*/ \ aKd5@  
package NetFox; ;iX<`re~  
5w3Fqu>39?  
F@SG((`  
public class SiteInfoBean { otriif@+Z  
Da,Tav%b  
>;lKLGJrd>  
private String sSiteURL; //Site's URL B@cz ?%]  
private String sFilePath; //Saved File's Path 0D3OE.$0  
private String sFileName; //Saved File's Name tY_5Pz(@
 
private int nSplitter; //Count of Splited Downloading File {BOLPE-  
2P}I'4C-  
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public SiteInfoBean() P;U@y"s  
{//nSplitter的缺省值为5 Jt=>-Spj  
//default value of nSplitter is 5 h|W%4|]R)  
this("","","",5); n<R \w''x  
} Rc9<^g`  
#+G`!<7/@f  
/H&aMk}J@y  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Auac>')&Q  
{ Q_}n%P:u  
sSiteURL= sURL; K`(#K#n  
sFilePath = sPath; |5ONFde"0  
sFileName = sName; {nRUH*(d9  
this.nSplitter = nSpiltter; iZTa>@  
,)$Wm-  
h$&rE@N|  
} Je~p%m#e;K  
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I~RcOiL)  
public String getSSiteURL() yQ-hnlzn~  
{ SCq3Ds^  
return sSiteURL; w2Kq(^?  
} cjY@Ot*i$  
z93nYY$`Y  
_LLshV3  
public void setSSiteURL(String value) t-EV h~D1p  
{ C'<'7g4  
sSiteURL = value; yBe(^ n  
} <Kp+&(l,l  
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P#bm uCOS  
public String getSFilePath() M,G8*HI"  
{ )52#:27F  
return sFilePath; ,\>g  
} pn*d[M|k  
>w2f8tW`PP  
I}%mfojC  
public void setSFilePath(String value) c}cG<F  
{ J/[7d?hI/  
sFilePath = value; hg&u0AQ2  
} 1>;6x^_h0S  
pXNtN5@FQ  
B[7A  
public String getSFileName() B3.X}ys#  
{ K*:Im#Q  
return sFileName; QRiF!D)Nk  
} v?{vg?vI  
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f  
L:^Y@[f  
public void setSFileName(String value) `>y[wa>9r  
{ 1sMV`qv>  
sFileName = value; vhX-Qkt}  
} 6ku8`WyoF  
G\uU- z$)  
13\Sh  
public int getNSplitter() L*IU0Jy>  
{ |&(H^<+Xp  
return nSplitter; wNbTM.@  
} sq48#5Tc^r  
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public void setNSplitter(int nCount) %{Xm5#
m  
{ EI<"DB  
nSplitter = nCount; HoMQt3C
 
} H]U"+52h  
} qPp]K?.  
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/* RlPjki"M
g  
**Utility.java 1XQ87~  
*/ ADTU{6UPS  
package NetFox; s!bHS_\e|  
 I8:"h  
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public class Utility { ,I("x2  
`Nkx7Z~w:  
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public Utility() byp.V_a}/  
{ Dy98[cL  
 'Dnq+  
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} K@I+]5E%?  
1a \=0=[  
//线程睡眠 Lqg7D\7j  
public static void sleep(int nSecond) N45s'rF  
{  <Wp`[S]r  
try{ 7&#'c8]/qh  
Thread.sleep(nSecond); ~_(!}V
 
} 0m qSA  
catch(Exception e) 9 Wxq)  
{ R65;oJh  
e.printStackTrace (); R9S7_u  
} D86K$IT  
} SZN
FE  
FuIWiO(  
//日志 O<gP)ZW~  
public static void log(String sMsg) BF@m)w.v  
{ 0;.e#(`-  
System.err.println(sMsg); bfcD5:q  
} u0<d2Y  
0]f?Dx/8  
c`Lpqs`  
public static void log(int sMsg) eW<!^Aer  
{ LX&=uv%-^  
System.err.println(sMsg); J$o[$G_Z  
} 2n<qAl$t  
} bvt-
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fSm?27_  
/* yTMGIS
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**TestMethod.java Ktj(&/~}  
*/ ?,A8
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package NetFox; [C*Xk{e  
4jI*Y6Wkz  
Y
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public class TestMethod { GcU(:V2o  
av$\@4I  
5wVi{P5+  
public TestMethod() ixUiXP  
{ ///xx/weblogic60b2_win.exe LQuYCfj|  
try{ c"jhbH!u4  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?j ;,q  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); TO8\4p*tE  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !7#froh  
fileFetch.start(); /-cX(z 7  
} h_}BmJh_  
catch(Exception e){e.printStackTrace ();} lqwJ F &  
ce-m)o/  
9fk\Ay1P  
} <CdG[Ih  
LP-KD  
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public static void main(String[] args) _<&K]e@dp  
{ N*c?Er@8U  
new TestMethod(); `dq3=  
} pR^Y|NG!  
} mqfEs0~I  
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