http断点续传简单实现（java)

/* 0!tuUn  
**SiteFileFetch.java T>J ,kh  
*/ amWKykVS5  
package NetFox; ZEvK
 
import java.io.*; L<6nM ;d  
import java.net.*; )RQQhB  
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public class SiteFileFetch extends Thread { +
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SiteInfoBean siteInfoBean = null; //文件信息Bean ^sqzlF  
long[] nStartPos; //开始位置 > }kZXeR|  
long[] nEndPos; //结束位置 [8K :ml  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .bj:tmz  
long nFileLength; //文件长度 q4,/RZhzh  
boolean bFirst = true; //是否第一次取文件 U=5~]0g  
boolean bStop = false; //停止标志 M4% 3a j  
File tmpFile; //文件下载的临时信息 (^E5y,H<g  
DataOutputStream output; //输出到文件的输出流 ImbA2Gcs  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） "F4 3q8P  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?-8DS5  
{ h.NCG96S  
siteInfoBean = bean; Jm"W+! E  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Hx!eCTO:*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7U2B=]<e-  
if(tmpFile.exists ()) |I{3~+E h  
{ !T 9CpIM%  
bFirst = false; 8~&=vc  
read_nPos(); .i^@v<+  
} >7~,w1t  
else ngI+afo   
{ 1qBE|PwBp  
nStartPos = new long[bean.getNSplitter()]; 'pB?  
nEndPos = new long[bean.getNSplitter()]; k;)mc+ ~+  
} w^,Xa  
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} GK[9IF#_>  
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public void run() hTmJ ~m'J  
{ .L]5,#2([  
//获得文件长度 [(&aVHUj  
//分割文件 #zBqj;p  
//实例FileSplitterFetch u7j,Vc'~  
//启动FileSplitterFetch线程 $\bVu2&I  
//等待子线程返回 $1Zr.ERL|(  
try{ =%s6QFR  
if(bFirst) }w-M.  
{ ai;Q,Vy  
nFileLength = getFileSize(); #&1gVkvp  
if(nFileLength == -1) iSg0X8J)  
{ Q{an[9To~P  
System.err.println("File Length is not known!"); T8x8TN"  
} p(K^Zc  
else if(nFileLength == -2) tmoaa!yRnT  
{ B]Ec  
System.err.println("File is not access!"); #^R@EZ  
} M^>l>?#rl  
else lcgG5/82  
{ 8si{|*;hL  
for(int i=0;i<nStartPos.length;i++) VT=gb/W6)a  
{ S4-jFD)U  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); t)rPXvx}!  
} :R>RCR2g)  
for(int i=0;i<nEndPos.length-1;i++) k8%@PC$  
{ xE
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nEndPos = nStartPos[i+1]; 7AWq3i{  
} PN:`SWP  
nEndPos[nEndPos.length-1] = nFileLength; .k +>T*c{  
} Ih4$MG6QC  
} P"]l/  
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oN%zpz;OR  
//启动子线程 6NHP/bj<1V  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; a'.7)f[g}  
for(int i=0;i<nStartPos.length;i++) \u))1zRd  
{ &\b(  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;jN1n xF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), md!!$+a%|  
nStartPos,nEndPos,i); bf{_U%`  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9)o@d`*  
fileSplitterFetch.start(); FK`:eP{  
} V>GJO(9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?mSZQF:d@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); NJVkn~<  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Q w - z  
nEndPos = " + nFileLength); `H$=hr  
// fileSplitterFetch[nPos.length-1].start(); *X ;ch55\  
aw~h03R_Z  
*::.Uo4O  
//等待子线程结束 \okv}x^L=Z  
//int count = 0; Gf:dN_e6.  
//是否结束while循环 pl)?4[`LUc  
boolean breakWhile = false; AO|1m$xf  
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while(!bStop)  Fq5u%S  
{ ! Vlx  
write_nPos(); ('$*QC.M  
Utility.sleep(500); e6 x#4YH  
breakWhile = true; .k
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for(int i=0;i<nStartPos.length;i++) |v5 ge3-  
{ ~I%164B+/  
if(!fileSplitterFetch.bDownOver) NGkxg:  
{ =&qH%S
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breakWhile = false; Z P6p>?DQ  
break; x(R;xB  
} Vsw:&$  
} d_0(;'
 
if(breakWhile) ZbjUOlE02  
break; ,J-|.ER->  
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//count++; 4[MTEBx  
//if(count>4) kv,!"<  
// siteStop(); D6+3f#k6  
} "5O>egt  
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System.err.println("文件下载结束！"); .XiO92d9  
} vyB{35p$  
catch(Exception e){e.printStackTrace ();} vw(ecs^C  
} 0Q?%B6g$m[  
*" C9F/R  
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//获得文件长度 ?!/8~'xA6  
public long getFileSize() =Y6W Qf  
{ _)!*,\*`{  
int nFileLength = -1; QjG/H0*mP  
try{ D %)L"5C  
URL url = new URL(siteInfoBean.getSSiteURL()); " zD9R4\X.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); SK^(7Ws~0  
httpConnection.setRequestProperty("User-Agent","NetFox"); \AA9 m'BZ  
NH}o`x/  
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int responseCode=httpConnection.getResponseCode(); XMT@<'fI  
if(responseCode>=400) y 5=rr3%v  
{ RWo7_XO  
processErrorCode(responseCode); wvxz:~M  
return -2; //-2 represent access is error 9p3~WA/M@  
} Mx`';z8~  
aX6}:"R2C  
6sQ;Z|!Pz  
String sHeader; >~Tn%u<  
z=
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#\n*Qg4p  
for(int i=1;;i++) $x]/|u/9  
{ lNyyLLt  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Ak('4j!*}^  
//Utility.log(in.readLine()); [u2t1^#Ol  
sHeader=httpConnection.getHeaderFieldKey(i); CI$z+zN  
if(sHeader!=null) /2c(6h  
{ 9&.md,U'  
if(sHeader.equals("Content-Length")) C4.GtY8,d  
{ ~u2f`67
{  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); n*na6rV\k  
break; g<M!]0OK  
} Hi
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} ~9vK6;0  
else nGYimRYO  
break; TNA7(<"fV|  
} CM++:YvJ  
} lqJ92vi6Q  
catch(IOException e){e.printStackTrace ();} xT*c##  
catch(Exception e){e.printStackTrace ();} <!UnH6J.b  
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Utility.log(nFileLength); udA@9a^;  
4 l-UrnZ  
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return nFileLength; ~wv$uL8y  
} E?P>s T3B  
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//保存下载信息（文件指针位置） n5.sx|bI?  
private void write_nPos() .udLMS/_  
{ U.P1KRY|=  
try{ QSa#}vCp*  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Bl8|`R^g  
output.writeInt(nStartPos.length); &?H$-r1/?V  
for(int i=0;i<nStartPos.length;i++) 7Vh  
{ w)@Wug  
// output.writeLong(nPos); S\:+5}  
output.writeLong(fileSplitterFetch.nStartPos); 1 Ga3[g  
output.writeLong(fileSplitterFetch.nEndPos); R5^6Kwu  
} E&y)`>Nq{  
output.close(); Xy=ETV%  
} 3x+=7Mg9  
catch(IOException e){e.printStackTrace ();} 2sk7E'2(  
catch(Exception e){e.printStackTrace ();} ``:[Jr&  
} uyB2   
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//读取保存的下载信息（文件指针位置） \ f+;X  
private void read_nPos() 'r%(,=L  
{ ux(~+<k  
try{ `pZX!6Wn  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); rM A%By^L-  
int nCount = input.readInt(); C`kqsK  
nStartPos = new long[nCount]; ~//E'V-  
nEndPos = new long[nCount]; wLqj<ot  
for(int i=0;i<nStartPos.length;i++) Qr3!6  
{ 9cP{u$  
nStartPos = input.readLong(); Q*ELMib  
nEndPos = input.readLong(); w->Y92q]  
} , ftJw  
input.close(); "49dsKIOH  
} {%9@{Q'T.s  
catch(IOException e){e.printStackTrace ();} vCJa%}  
catch(Exception e){e.printStackTrace ();} ny1O- `!1  
} md'wre3  
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private void processErrorCode(int nErrorCode) W7 Iy_>  
{ ut560,h~  
System.err.println("Error Code : " + nErrorCode);
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} }kvix{  
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l$9k:#\FD  
//停止文件下载 !0Nf`iCQ(  
public void siteStop() i)X~L4gn  
{ +<F3}]]  
bStop = true; PLs`Ci|`  
for(int i=0;i<nStartPos.length;i++) uE9,N$\L_  
fileSplitterFetch.splitterStop(); 7R:Ij[dV  
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} {._'Q
[  
} _%D7D~2r|  
//负责部分文件的抓取 e8xq`:4Y
 
**FileSplitterFetch.java [[AO6.Z  
*/ B47I?~{  
package NetFox; o(Z~J}l({  
AkS16A  
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import java.io.*; c]#}#RJ`\  
import java.net.*; 1aRTvaG
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public class FileSplitterFetch extends Thread { ;#v3C;  
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String sURL; //File URL Icg-rwa<Z  
long nStartPos; //File Snippet Start Position b,~pwbHf  
long nEndPos; //File Snippet End Position ^t gjs$M|  
int nThreadID; //Thread's ID -`\rDPGf  
boolean bDownOver = false; //Downing is over |*g#7YL  
boolean bStop = false; //Stop identical vMou`[\WlJ  
FileAccessI fileAccessI = null; //File Access interface ,s3|  
6&SNFOX{@  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException \z!lw  
{ `IwZVz  
this.sURL = sURL; ~//9Nz~;3  
this.nStartPos = nStart; ;u'VR}4ph  
this.nEndPos = nEnd; MW rhVn{R  
nThreadID = id; kGAgXtE  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -%fj-Y7y  
} ]ASw%Lw)  
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ZOV,yuD{8{  
public void run() )$E){(Aa  
{ [}HPV+j=U  
while(nStartPos < nEndPos && !bStop)  d6tLCQ  
{ m-Jy 4f#  
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}WC[<AqI  
try{ qF bj~ec  
URL url = new URL(sURL); :3Q:pKg  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]`x+wWe  
httpConnection.setRequestProperty("User-Agent","NetFox"); \X*y~)+K`  
String sProperty = "bytes="+nStartPos+"-"; LZ_VLW9wE  
httpConnection.setRequestProperty("RANGE",sProperty); ,S`n?.&& 7  
Utility.log(sProperty); 5O]tkHYR  
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InputStream input = httpConnection.getInputStream(); SQK82/  
//logResponseHead(httpConnection); 8ly)G  
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byte[] b = new byte[1024]; 1DcBF@3sWG  
int nRead; Q}B]b-c+E  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) QEt"T7a[/  
{ oZY|o0/9  
nStartPos += fileAccessI.write(b,0,nRead); )GG9
[%H!  
//if(nThreadID == 1) Y2l;NSWU  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8o|C43Q_  
} ;AOLbmb)H4  
=bD.5,F)  
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Utility.log("Thread " + nThreadID + " is over!"); nsi?.c&0!  
bDownOver = true; OjlX<y.  
//nPos = fileAccessI.write (b,0,nRead); E%v0@  
} [nVBnB  
catch(Exception e){e.printStackTrace ();} sv%E5@  
} 5<PNl~0  
} Sq,>^|v4&e  
#b428-  
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//打印回应的头信息 4pT^*  
public void logResponseHead(HttpURLConnection con) MFa/%O_*  
{ zC)JOykI%  
for(int i=1;;i++) oc,I,v  
{ l([aKm#  
String header=con.getHeaderFieldKey(i); D )`(b  
if(header!=null) &\6},
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); aeN #<M&$<  
Utility.log(header+" : "+con.getHeaderField(header)); L)U*dY  
else ER9{D$  
break; BrSvkce  
} C=&n1/  
}
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public void splitterStop() Ip7#${f5M  
{ "!vY{9,  
bStop = true; n!Y_SPg   
} v+{{j|x=  
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} VV1sadS:S`  
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/* Hm'fK$y(  
**FileAccess.java "TaLvworb4  
*//文件访问(定位，写) *8,W$pe3  
package NetFox; B`R@%US  
import java.io.*; 9kWI2cLzQt  
)N- '~<N  
,|yscp8  
public class FileAccessI implements Serializable{ ;Z0&sFm  
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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 O6?{@l  
RandomAccessFile oSavedFile; SN{A@dyt  
long nPos; '/UT0{2;rS  
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,h1\PT9ULY  
public FileAccessI() throws IOException ,_YI:xie|c  
{ ZJWpb  
this("",0); &'k(v(>n,  
} B6&[_cht  
~x9J&*zxM  
1o\2\B=k{  
public FileAccessI(String sName,long nPos) throws IOException Heh&;c  
{ Jy}~ZY  
oSavedFile = new RandomAccessFile(sName,"rw"); h9m|f|cH  
this.nPos = nPos; c"kB@P  
oSavedFile.seek(nPos); %>+lr%B  
} "Ua-7Q&A  
/dg?6XT/  
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public synchronized int write(byte[] b,int nStart,int nLen) j~\FDcG*ed  
{ H?;+C/-K`_  
int n = -1; dpS@:  
try{ >H;m[  
oSavedFile.write(b,nStart,nLen); tx[;& ;  
n = nLen; _I;hM  
} |G/WS0  
catch(IOException e) 8T8
8  
{ O2"5\@HfE  
e.printStackTrace (); "w3%BbIx  
} ]EqwDw4  
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]  
return n; r*9*xZ>8u  
} 2=uwGIF  
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} 4))N(m%3F  
bD.KD)5  
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/* |!{Y:f;  
**SiteInfoBean.java `N8t2yF  
*/ }VeE4-p B  
package NetFox; c&C*'c-r  
2d&]V]:R*  
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public class SiteInfoBean { Z?u}?-b1\H  
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private String sSiteURL; //Site's URL I>{o]^xw-D  
private String sFilePath; //Saved File's Path U7HfDDh  
private String sFileName; //Saved File's Name +QP(ATdM  
private int nSplitter; //Count of Splited Downloading File oSIP{lfp2Q  
EVP{7}K1  
"r1 !hfIYf  
public SiteInfoBean() 2}15FXgN  
{//nSplitter的缺省值为5 '3?-o|v@D  
//default value of nSplitter is 5 nf1O8FwRb  
this("","","",5); wV-9T*QrM  
} <!F".9c@A  
"RgP!  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) !,]2.:{0z  
{ c#TV2@  
sSiteURL= sURL; U9jdb9 |  
sFilePath = sPath; {.ypZ8JU  
sFileName = sName; (__$YQ-  
this.nSplitter = nSpiltter; {vdY(  
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} d:"7Tw2v+  
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public String getSSiteURL() M4(57b[`  
{ (I/iD.A  
return sSiteURL; ]-_ ma  
} "z*.Bk  
?TJ4L/"(k6  
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public void setSSiteURL(String value) E1SWZ&';  
{ uh`5:V  
sSiteURL = value; Swh\^/B8  
} E\TWPV'/  
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public String getSFilePath() <KfR)7I$0a  
{ ?d+ri  
return sFilePath; [5tvdW6Z&  
} c\/-*OYr<  
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[5ncBY*A7  
public void setSFilePath(String value) i[I&m]N  
{ Ve${g`7&  
sFilePath = value; a,(nf1@5  
} TO.STK`  
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w 62m}5eA  
public String getSFileName() [XttT  
{ (H"{r  
return sFileName;  q*94vo-  
} $41<ldJ  
"?<(-,T  
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public void setSFileName(String value) &xA>(|a\&-  
{ vxOnv8(  
sFileName = value; (E7"GJ  
} &nwS7n1eb  
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M?DZShkV_  
public int getNSplitter() EV-sEl8ki  
{ _>BYUPY  
return nSplitter; bDudETl  
} q%QvBN  
J5n6K$.d  
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public void setNSplitter(int nCount) ^M%P43  
{ ?PqkC&o[q  
nSplitter = nCount; ZjY,k  
} ^$}O?y7O  
} v_Df+  
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/* &-{%G=5~e%  
**Utility.java _>n)HG  
*/ X)6G:cD  
package NetFox; %hN(79:g  
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public class Utility { h Ypj  
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public Utility() 60]VOQku  
{ ju3@F8AI  
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} (n8?+GCa  
uD?RL~M  
//线程睡眠 G[]%1 _QCO  
public static void sleep(int nSecond) Dt>tTU 6  
{ A
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try{ 'jMs&  
Thread.sleep(nSecond); f3qR7%X?
 
} 7w" !"W#  
catch(Exception e) H ?9Bo!  
{ 5'+g[eNyBV  
e.printStackTrace (); 5._QI/d)'J  
} R-dv$z0  
} ,jeHL@>w[  
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//日志 7Hv6>z#m  
public static void log(String sMsg) jD"nEp-  
{ d}fd^x/  
System.err.println(sMsg); @BjB Mi,  
} H.]V-|U  
,r~^<m  
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public static void log(int sMsg) VyNF)$'T  
{ Oi& 9FS  
System.err.println(sMsg); @ U"Ib  
} FN/l/OSb  
} Z.Z31yF:f  
^Ss<<  
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/* ^_3$f  
**TestMethod.java %%n&z6w-  
*/ ^`dMjeF  
package NetFox; `L <sZ;Cj  
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public class TestMethod { 5uSg]2:  
g#l!b%$  
9Z=hg[`]<
 
public TestMethod() s/~pr.>-l  
{ ///xx/weblogic60b2_win.exe Gdx%#@/  
try{  -L2 +4
 
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); r/0#D+A  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); oNl-!W   
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5N6R%2,A  
fileFetch.start(); K*'AjT9wX+  
} sA: /!9  
catch(Exception e){e.printStackTrace ();} $^ir3f+  
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} -gC%*S5&  
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public static void main(String[] args) I|Hcs.uW  
{ }V.fY3J-  
new TestMethod(); _f "I%QTL  
} GpO@1 C/  
} TQ/#  
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