http断点续传简单实现（java)

/* C[#C/@  
**SiteFileFetch.java i*!2n1c[  
*/ zf^|H% ~^  
package NetFox; \ptjnwC^O  
import java.io.*; Unb3 Gv#O  
import java.net.*; @A*>lUo  
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public class SiteFileFetch extends Thread { 'lu3BQvfh  
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SiteInfoBean siteInfoBean = null; //文件信息Bean \[*q~95$v  
long[] nStartPos; //开始位置 3 5L0CM  
long[] nEndPos; //结束位置 HTvUt*U1  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 s2 :Vm\  
long nFileLength; //文件长度 <l5m\A  
boolean bFirst = true; //是否第一次取文件 ``6-   
boolean bStop = false; //停止标志 1v,R<1)&  
File tmpFile; //文件下载的临时信息 .sFN[>)  
DataOutputStream output; //输出到文件的输出流 M:iH7K  
P*VZ$bUe5@  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） x',6VTz^  
public SiteFileFetch(SiteInfoBean bean) throws IOException UEfY'%x  
{ v7`{6Pf_$  
siteInfoBean = bean; jF/S2Ty2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .V3e>8gw3  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); v'S5F@ln  
if(tmpFile.exists ()) BpYxH#4  
{ ('Uj|m}9  
bFirst = false; Z,Us<du  
read_nPos(); <yBa5m@/  
} U/|JAg#  
else SO[ u4b_"h  
{ uKvdL "  
nStartPos = new long[bean.getNSplitter()]; 2+~gZxHq  
nEndPos = new long[bean.getNSplitter()]; V'MY+#  
} VfP\)Rl
 
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} VY+P c/b  
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public void run() h0g?=hJq  
{ .Y^cs+-o  
//获得文件长度 u#Jr_ze  
//分割文件 h&}iH  
//实例FileSplitterFetch 7C,giCYU  
//启动FileSplitterFetch线程 eNVuw:Q+  
//等待子线程返回 ?# _{h  
try{ N~l*//Ep  
if(bFirst) UOl*wvy  
{ ugE!EEy[^  
nFileLength = getFileSize(); yRXWd*9  
if(nFileLength == -1) 0< vJ*z|_  
{ -GHd]7n  
System.err.println("File Length is not known!"); ]W`?0VwF  
} $/;K<*O$  
else if(nFileLength == -2) HK~SD:d  
{ s*<T'0&w0S  
System.err.println("File is not access!"); yGAFQ|+  
} dr:x0>  
else dpylJ2  
{ <r t$~}  
for(int i=0;i<nStartPos.length;i++) ]77f`<q<}!  
{ L+<h5>6  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); {5<fvMO!6  
} bp=r]nO  
for(int i=0;i<nEndPos.length-1;i++) CW?Z\  
{ =&$z Nc4h  
nEndPos = nStartPos[i+1]; %N fpEo  
} OoH-E.lp  
nEndPos[nEndPos.length-1] = nFileLength; YI,t{Wy  
} QRf>lZP  
} 2HN*j~>i~  
yxp,)os:  
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//启动子线程 2[qfF6FHA  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; SM4`Hys;p  
for(int i=0;i<nStartPos.length;i++) $m2#oI'D  
{ &|#[.ti1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), A?!RF7v  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), N\g=9o|Q  
nStartPos,nEndPos,i); !uW*~u  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I@/ G#3Zr  
fileSplitterFetch.start(); Z6i~Dy3  
} $$1t4=Pz  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), b2UDPW  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $a*7Q~4  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^?+[yvq  
nEndPos = " + nFileLength); ZxwrlaA  
// fileSplitterFetch[nPos.length-1].start(); 5buW\_G)  

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//等待子线程结束 h' !C  
//int count = 0; -?)^ hbr  
//是否结束while循环 iv *$!\Cd  
boolean breakWhile = false; S=!WFKcJR  
NknS:r&2  
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while(!bStop) HdqB B
  
{ xyk%\&"7  
write_nPos(); x'x5tg  
Utility.sleep(500); ;kk[x8
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breakWhile = true; OVi<d  
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for(int i=0;i<nStartPos.length;i++) t2(X  
{ $kTm"I  
if(!fileSplitterFetch.bDownOver) ))|d~m  
{ ,Zn6T"[$  
breakWhile = false; t[`LG)  
break; cj>UxU][eS  
} M=liG+d  
} F(ydq
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if(breakWhile) y2_rm  
break; FprdP*/  
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//count++; DlUKhbo$g  
//if(count>4) Hh^ "c}  
// siteStop(); kJ5z['4?  
} a
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6v3l^~kc'  
/=p[k^A  
System.err.println("文件下载结束！"); hAf/&yA@  
} _,L_H[FN  
catch(Exception e){e.printStackTrace ();} (Ut8pa+yX  
} @\?ubF  
-4Hb]#*2  
$^iio@SW{  
//获得文件长度 %jjPs.  
public long getFileSize() ; R+>}6  
{ n\((#<&
 
int nFileLength = -1; S<i1t[E@W  
try{ )%@7tx  
URL url = new URL(siteInfoBean.getSSiteURL()); 66pjWS {X  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Nj4CkMM[3  
httpConnection.setRequestProperty("User-Agent","NetFox"); eTp|!T  
61H_o7XXk  
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int responseCode=httpConnection.getResponseCode(); k4V3.i!E  
if(responseCode>=400) 5K1cPU~o_b  
{ VBL4cU8D  
processErrorCode(responseCode); Q)0KYKD+@  
return -2; //-2 represent access is error nnj<k5  
} z='%NZY  
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String sHeader; N5*Qnb8  
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for(int i=1;;i++) 9s"st\u 4  
{ =Mx"+/Yo*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Hnt*,C.0  
//Utility.log(in.readLine()); ~".@mubt1$  
sHeader=httpConnection.getHeaderFieldKey(i); "M5  
if(sHeader!=null) S#M8}+ZD,  
{ 5\pS8<RJ;  
if(sHeader.equals("Content-Length")) Fy{yg]O"  
{ ikc1,o  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |`:cB  
break; Eto"B"  
} $L= Dky7  
} |s! _;6  
else \eKXsO"d  
break; 1k6asz^T  
} !s-A`} s+  
} xJ$uoy3+  
catch(IOException e){e.printStackTrace ();} HZAT_  
catch(Exception e){e.printStackTrace ();} gttsxOgktH  
#$BFTlm|  
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Utility.log(nFileLength); u"qu!EY2  
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return nFileLength; r[!~~yu/o  
} U*a#{C7"  
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//保存下载信息（文件指针位置） "]=OR>  
private void write_nPos() 73X*|g  
{ i$] :Y`3h  
try{ 8~O#@hB~3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Ll=G+cw6P  
output.writeInt(nStartPos.length); e^eJ!~0  
for(int i=0;i<nStartPos.length;i++) $Xwk8<  
{ m[=SCH-;  
// output.writeLong(nPos); #tKks:eL  
output.writeLong(fileSplitterFetch.nStartPos); dQIF'==6  
output.writeLong(fileSplitterFetch.nEndPos); N%f"W&ci  
} bWA_a]G  
output.close(); :(XyiF<Ud  
} AVjRhe  
catch(IOException e){e.printStackTrace ();} (m2%7f.I  
catch(Exception e){e.printStackTrace ();} -E\G3/*51  
} p'LLzc##  
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//读取保存的下载信息（文件指针位置） ,5zY1C==Ut  
private void read_nPos() H'3 pHb  
{ GImPPF  
try{ h i!K-_Uy  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); OulRqbL2  
int nCount = input.readInt(); 75H!i$(*+  
nStartPos = new long[nCount]; !y_L~81?  
nEndPos = new long[nCount]; D-@6 hWh~  
for(int i=0;i<nStartPos.length;i++) EC$F|T0f  
{ @VP/kut  
nStartPos = input.readLong(); tiGH#~?  
nEndPos = input.readLong(); #8t=vb3  
} a"P & 9c  
input.close(); WY|~E
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} {s@!N  
catch(IOException e){e.printStackTrace ();} H9jlp.F  
catch(Exception e){e.printStackTrace ();} c),UO^EqV  
} Lfx a^0  
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private void processErrorCode(int nErrorCode) sB:
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{ ?W ^`Fa)]o  
System.err.println("Error Code : " + nErrorCode); 8Q/cJ+&  
} JGq9RB]D$  
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#vK99S2  
//停止文件下载 @}UOm-M  
public void siteStop() }6LcimQyK  
{ t_I-6`8o]  
bStop = true; n.N0Nhd  
for(int i=0;i<nStartPos.length;i++) "=]'"'B:  
fileSplitterFetch.splitterStop(); ?_{{iil  
w`boQ_Ir  
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} te;bn4~
  
} -"Kjn`8  
//负责部分文件的抓取 ^&F.T-(A  
**FileSplitterFetch.java 'O~_g5kC  
*/ [D|Uwq  
package NetFox; q\P{h ij  
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import java.io.*; P<1&kUZL  
import java.net.*; G|&$/]~  
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public class FileSplitterFetch extends Thread { l}S96B  
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vG}\Amx+  
String sURL; //File URL T;k
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long nStartPos; //File Snippet Start Position 2CtCG8o  
long nEndPos; //File Snippet End Position e'|P^G>g  
int nThreadID; //Thread's ID !Y^B{bh  
boolean bDownOver = false; //Downing is over =AK6^v&on  
boolean bStop = false; //Stop identical o 8^!wGY  
FileAccessI fileAccessI = null; //File Access interface vO zUAi  
sN[<{;K4  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException F%ukT6xp  
{ SX?hu|g_r  
this.sURL = sURL; M1DV9~S  
this.nStartPos = nStart; r_^
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this.nEndPos = nEnd; 's8LrO(=  
nThreadID = id; p|>/Hz1v  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 0ZAtBq.s  
} !q+ %]k?x  
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public void run() zW95qxXg  
{ yrMakT=  
while(nStartPos < nEndPos && !bStop) ltl(SIi  
{ v(/T<^{cuk  
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try{ +AyrKs?h  
URL url = new URL(sURL); N%\!eHxy  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $5`P~Q'U  
httpConnection.setRequestProperty("User-Agent","NetFox"); @e_ bG
@  
String sProperty = "bytes="+nStartPos+"-"; Q9b.]W  
httpConnection.setRequestProperty("RANGE",sProperty); <m#ov G6  
Utility.log(sProperty); ee.#Vhz  
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/L8Q[`;.  
InputStream input = httpConnection.getInputStream(); tB_GEt2M  
//logResponseHead(httpConnection); I]|X6  
s=&&gC1
 
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byte[] b = new byte[1024]; B'OUT2cgB  
int nRead; ]4m;NId  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ndn)}Z!0h  
{ -rSpgk0wL  
nStartPos += fileAccessI.write(b,0,nRead); #MbkU])  
//if(nThreadID == 1) 0L_JP9e  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YQWGv,47\  
} /G`'9cD  
B 3Y,|*  
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Utility.log("Thread " + nThreadID + " is over!"); :d v{'O  
bDownOver = true; B zmmE2~*  
//nPos = fileAccessI.write (b,0,nRead); a7+w)]r  
} cRm+?/  
catch(Exception e){e.printStackTrace ();} zrqQcnx9(m  
} N^\<y7x  
} #"J8]3\F  
B8){  
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//打印回应的头信息 {k4)f ad\  
public void logResponseHead(HttpURLConnection con) ?6;9r[ p  
{ o}q>oa b z  
for(int i=1;;i++) WZ\bm$  
{ X}@^$'W  
String header=con.getHeaderFieldKey(i); zq1je2DB  
if(header!=null) OIpkXM
 
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >/@wht4- j  
Utility.log(header+" : "+con.getHeaderField(header)); 7>#?-, B  
else J:<mq5[  
break; y:t@X
~  
} 5L6_W-n{  
} 37OU  
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public void splitterStop() kj_MzgC'?  
{ 6#[  
bStop = true; . V5Pr}"y  
} GRM:o)4;#  
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}q<p;4<\F  
} Gw!VPFV>W  
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/* .r ,wc*SF  
**FileAccess.java b/[$bZD5o  
*//文件访问(定位，写) ZhqGUb  
package NetFox; tQR qQ  
import java.io.*; k^VL{z:EWB  
6d7E@}<  
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public class FileAccessI implements Serializable{ p!oO}gE  
U/}("i![Dy  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 "A(D}~i  
RandomAccessFile oSavedFile; ! 3 ;;6  
long nPos; V;pRw`  
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public FileAccessI() throws IOException /Fr*k5I  
{ MnLo{G]  
this("",0); ?^3Y+)
}  
} oV/:T\Qn=  
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2v$\mL  
public FileAccessI(String sName,long nPos) throws IOException &0b\E73  
{ pyw]ydB  
oSavedFile = new RandomAccessFile(sName,"rw"); tZXq<k9  
this.nPos = nPos; :$=]*54`T  
oSavedFile.seek(nPos); !We9T)e  
} *KV^X(/  
awU!3)B  
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public synchronized int write(byte[] b,int nStart,int nLen) 8l>7=~Egp  
{ <`
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int n = -1; {^@vCBE+  
try{ H'"=C&D~  
oSavedFile.write(b,nStart,nLen); cy64xR BB  
n = nLen; M7fPaJKL  
} {1"kZL  
catch(IOException e) ~v@.YJoZ4Z  
{ HIqe~Vc  
e.printStackTrace (); j6d{r\!$4  
} rDWwu'  
*DgRF/S  
XZ=%XB:?  
return n; n v ?u  
} <CcSChCg  
:sS4T&@1=  
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} 6{w'q&LYcE  
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/* D4T42L  
**SiteInfoBean.java q:1n=iEi  
*/ m f\tMik<  
package NetFox; $WiUoS  
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public class SiteInfoBean { 'Yaq; mDY  
y5j ;Daq  
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private String sSiteURL; //Site's URL "H9q%S,FH  
private String sFilePath; //Saved File's Path QuBA'4ht  
private String sFileName; //Saved File's Name .:t&LC][  
private int nSplitter; //Count of Splited Downloading File a`D`v5G t  
/&E]qc*-p  
[4Q;5 'Dj  
public SiteInfoBean() ~Zw37C9J  
{//nSplitter的缺省值为5 ?r}2JHvN  
//default value of nSplitter is 5 sVH w\_F$  
this("","","",5); l\TL=8u2c  
} RS|*3 $1  
.7+"KP:  
,E8g~ZUY9  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) `NyO|9/4
 
{ t^=S\1"R\  
sSiteURL= sURL; g)}q3-<AK>  
sFilePath = sPath; YlXqj\a  
sFileName = sName; /GF"D5  
this.nSplitter = nSpiltter; bduHYs+rq  
LlD=c  
" eS-i@  
} 4j(*%da  
94?/Rhs5  
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public String getSSiteURL() 9fYof  
{ 1I%niQv5t  
return sSiteURL; 6A4{6B  
} 4 g8t  
PB#EU9  
Y2|c;1~5$  
public void setSSiteURL(String value) >ktekO:H  
{ D7Ds*X`!l  
sSiteURL = value; P!!:p2fo  
} !,~C  
/px`FuJI(  
>+%p}l:<\  
public String getSFilePath() p3B_NsXVZ  
{ T^gi^{  
return sFilePath; ,w,)n^  
} 6Z-[-0o+g  
7'7o^> !  
~Q)Dcit-  
public void setSFilePath(String value) .p'\@@o5  
{ -];Hb'M.!e  
sFilePath = value; 6W'2w?qj?4  
} \r}*<CRr6  
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*jl_,0g]  
public String getSFileName() 8u Z4[  
{ ;zo?o t/  
return sFileName; )J&!>GP  
} $]b&3_O$N8  
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public void setSFileName(String value) ]2xoeNF/W{  
{ kN*\yH|  
sFileName = value; ntF#x.1Pm  
} @TnAO8Q>XD  
(<#Ns W!z  
4\Cb4jq%/  
public int getNSplitter() !7anJl
  
{ _ 3>|1RB  
return nSplitter; Jm}zit:o  
} Oxf,2r  
++0xa%:  
?T:$:IHw  
public void setNSplitter(int nCount) @0rwvyE=+3  
{ .:jfNp~jt  
nSplitter = nCount; 5$f*fMd;  
} f%Bmx{Ttq  
} z/7"!  
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/* #FV`*G  
**Utility.java ]6EXaf#  
*/ `'<
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package NetFox; |/AY!Y3
 
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public class Utility { b."1p7'  
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public Utility() (1b%);L7  
{ *S4*FH;8  
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e#$ZOK)`  
} goV[C]|  
sGD b<  
//线程睡眠 .J3Dk=/  
public static void sleep(int nSecond) JM
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{ Px))O&w{  
try{ A">A@`}  
Thread.sleep(nSecond); -!]dU`:(X  
} yjP;o`z%  
catch(Exception e) (S
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{ ?(CMm%(8  
e.printStackTrace (); 3#Hx^H
 
} @rVBL<!o,  
} S?_ ;$Cn  
3QrYH @7zx  
//日志 Xpd^^  
public static void log(String sMsg) ii@O&g  
{ UN}jpu<h  
System.err.println(sMsg); xdH*[  
} ]OOL4=b  
0oi =}lV  
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public static void log(int sMsg) K}U}h>N  
{ Y@Kp'+t(!  
System.err.println(sMsg); m,U`hPJ  
} NwdA@"YQ|  
} 'L2M W  
$Y4;Xe=  
qe:,%a-9  
/* t>T |\WAAL  
**TestMethod.java &V&0kp@+  
*/ ToN$x^M w  
package NetFox; dZ7+Iw;m  
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,]'?Gd  
public class TestMethod { WoiK _Ud  
y3K9rf  
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public TestMethod() )[>b7K$f  
{ ///xx/weblogic60b2_win.exe B&`hvR  
try{
PQRh5km  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); yjVPaEu]aU  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); <"@~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +M6qbIO  
fileFetch.start(); 8eSIY17  
} *Ki ],>_~  
catch(Exception e){e.printStackTrace ();} u9FXZK7  
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} 8_K22]c5  
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public static void main(String[] args) Eq9TJt'3y  
{ 5eO`u8M  
new TestMethod(); s45Y8!c  
} Yo c N
@s
 
} #s1O(rLRl  
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