http断点续传简单实现（java)

/* ' pfkbmJ  
**SiteFileFetch.java smPZ%P}P+c  
*/ 8*EqG5OP  
package NetFox; K Vnz{cx`  
import java.io.*; KNSMx<GP  
import java.net.*; 4R&pb1eF  
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public class SiteFileFetch extends Thread { Ur(< ]  
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SiteInfoBean siteInfoBean = null; //文件信息Bean QxiAC>%K  
long[] nStartPos; //开始位置 t]+h.  
long[] nEndPos; //结束位置 vlPViHF.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 UxvT|~"  
long nFileLength; //文件长度 41c4Xj?'  
boolean bFirst = true; //是否第一次取文件 cD9.L  
boolean bStop = false; //停止标志 qjH/E6GGg  
File tmpFile; //文件下载的临时信息  ?S'Wd=  
DataOutputStream output; //输出到文件的输出流 .x_F4#Ka  
?-=<7 ~$  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） %)=c#H1  
public SiteFileFetch(SiteInfoBean bean) throws IOException KA elq
*  
{ VujIKc#4  
siteInfoBean = bean; RC^k#+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); yK w.69.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); vgN%vw pL  
if(tmpFile.exists ()) \1oN't.  
{ O[ug7\cl+  
bFirst = false; B1o*phM g  
read_nPos(); W"H(HA  
} &'c&B0j  
else F+/#ugI  
{ 4]no#lVRJ  
nStartPos = new long[bean.getNSplitter()]; w5q'M  
nEndPos = new long[bean.getNSplitter()]; FLQ>,=O  
} _.5ABE  
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} aA-
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public void run() Z;cA_}5  
{ RH"EO4  
//获得文件长度 /;`-[  
//分割文件 -qpe;=g&f  
//实例FileSplitterFetch .<Jq8J  
//启动FileSplitterFetch线程 U)D}J_Zi(  
//等待子线程返回 j~O"=?7!O  
try{ 0(+dXzcwM  
if(bFirst) v
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{ Oox,4
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nFileLength = getFileSize(); Duq.`XO  
if(nFileLength == -1) O[R
  
{ Z>hGqFZ0{  
System.err.println("File Length is not known!"); s:^Xtox/  
} MG4(,"c!  
else if(nFileLength == -2) 6eW9+5oL  
{ Z"E2ZSa0  
System.err.println("File is not access!"); c@{M),C~E  
} IaGF{O3.  
else 59k-,lyU,  
{ TJs~}&L  
for(int i=0;i<nStartPos.length;i++) {#&j
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{ ZvSEa{
  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); FIpJ>E"n  
} $aj:\A0f  
for(int i=0;i<nEndPos.length-1;i++) }PzHtA,V  
{ 'Xg9MS&  
nEndPos = nStartPos[i+1]; ,<fs+oi  
} #<yKG\X?  
nEndPos[nEndPos.length-1] = nFileLength; jNW/Biy4u  
}
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} yOyuMZo6  
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|],ocAN{  
//启动子线程 jiP^Hz"e  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; eI+p  
for(int i=0;i<nStartPos.length;i++) HQ^:5XH  
{ o_PQ]1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D>K=D"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), K<fB]44Y  
nStartPos,nEndPos,i); 'V}4_3#q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9tIE+RD  
fileSplitterFetch.start(); j_}f6d/h  
} 7?2<W-n  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d2*uY.,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); >C/O >g  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", K(Ak+&[  
nEndPos = " + nFileLength); Yn8aTg[J  
// fileSplitterFetch[nPos.length-1].start(); !6eF8T  
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//等待子线程结束 mh8)yy5\  
//int count = 0; ;b^"b{  
//是否结束while循环 6<9gVh<=w  
boolean breakWhile = false; JmbWE
X|  
{r1}ACw{  
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while(!bStop) H`NT`BE  
{ `<* tp@  
write_nPos(); rF=\H3`p3  
Utility.sleep(500); Il$Jj-)  
breakWhile = true; ihopQb+k^m  
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for(int i=0;i<nStartPos.length;i++) I5w>*F  
{ -h{|u{t  
if(!fileSplitterFetch.bDownOver) }N W0
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{ m]'P3^<{P  
breakWhile = false;  @+!u{  
break; N m@UM*D  
} Vnnl~|Xx  
} 8o!LgT5  
if(breakWhile) ;g_<i_*x#  
break; [,ZHn$\  
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//count++; F'^?s= QX  
//if(count>4)
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// siteStop(); 0-Vx!(  
} 'klYGp  
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System.err.println("文件下载结束！"); wak'L5GQE  
} 'Sjt*2blq  
catch(Exception e){e.printStackTrace ();} |M(0CYO  
} Ae>:i7.V  
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//获得文件长度 h"On9  
public long getFileSize() ')1p  
{ yo_;j@BGR  
int nFileLength = -1;  4,?ZNyl  
try{ 3nX={72<b  
URL url = new URL(siteInfoBean.getSSiteURL()); -)p| i~j^A  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]rc=oP;  
httpConnection.setRequestProperty("User-Agent","NetFox"); '+E\-X  
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int responseCode=httpConnection.getResponseCode(); )UAkg  
if(responseCode>=400) KN"<f:u  
{ ZMmf!cKY:'  
processErrorCode(responseCode); "E%3q3|"l  
return -2; //-2 represent access is error &T\,kq>)  
} 0'~Iv\s  
!r`/vQ#  
 R]"3^k*  
String sHeader; vJ0Zv> n-  
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for(int i=1;;i++) XcM.<Dn3  
{ < <]uniZ\  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); esK0H<]  
//Utility.log(in.readLine()); #qg(DgH 7  
sHeader=httpConnection.getHeaderFieldKey(i); wv&#lM(  
if(sHeader!=null)
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{ ;'4HR+E"  
if(sHeader.equals("Content-Length")) 1$1P9x@H  
{ tW}At  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )m.U"giG++  
break; @"'$e_jj"  
} vDcYz,  
} W^N|+$g>H  
else 7V-'><)gI  
break; /'Q2TLy=  
} _Sn45h@"  
} @szr '&\%A  
catch(IOException e){e.printStackTrace ();} p5JRG2zt  
catch(Exception e){e.printStackTrace ();} QBL|n+  
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Utility.log(nFileLength); `F4gal^ ^  
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return nFileLength; .+$ox-EK8  
} j-9Zzgr  
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//保存下载信息（文件指针位置） -8m3L  
private void write_nPos() sX,S]:X  
{ 5Sz}gP('  
try{ z`(">J  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ky=h7#wdv-  
output.writeInt(nStartPos.length); #gSLFM{p  
for(int i=0;i<nStartPos.length;i++) oxXCf%!  
{ olca Z  
// output.writeLong(nPos); LGT?/gup  
output.writeLong(fileSplitterFetch.nStartPos); B<oBo&uA  
output.writeLong(fileSplitterFetch.nEndPos); tzrvIVD  
} /a?qtRw  
output.close(); U*:E|'>  
} SaSj9\o  
catch(IOException e){e.printStackTrace ();} "r[Ob]/  
catch(Exception e){e.printStackTrace ();} (0u(<q
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} 66-G)+4  
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//读取保存的下载信息（文件指针位置） O#?@'1  
private void read_nPos() IA680^  
{ VCQo3k5 {  
try{ tQ(4UHqa~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); v:?l C<,  
int nCount = input.readInt(); ug^esB  
nStartPos = new long[nCount]; S<eB&q
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nEndPos = new long[nCount]; 1:22y:^j  
for(int i=0;i<nStartPos.length;i++) ';;X{a  
{ cUC!'+L  
nStartPos = input.readLong(); aM YtWj  
nEndPos = input.readLong(); /_</m?&.U&  
} I'0{Q`}  
input.close(); l;i/$Yu7  
} -mw`f)?Ev  
catch(IOException e){e.printStackTrace ();} p((a(Q/
  
catch(Exception e){e.printStackTrace ();} M.\V/OX  
} `T3B  
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private void processErrorCode(int nErrorCode) D|$Fw5!^k6  
{ y_r(06"z1  
System.err.println("Error Code : " + nErrorCode); (!%9#  
} 9PdD=9HH  
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//停止文件下载
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public void siteStop() vn4z C  
{ V6Y0#sTU  
bStop = true; CD[}|N  
for(int i=0;i<nStartPos.length;i++) (nAL;:$x2  
fileSplitterFetch.splitterStop(); z]R%'LGu  
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} w|c200Is}e  
} iF Zqoz  
//负责部分文件的抓取 Oi<yT"7  
**FileSplitterFetch.java 5i+cjT2  
*/ -tfUkGdx;l  
package NetFox; b_^y Ke^W  
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m UUNR,  
import java.io.*; nx{MUN7  
import java.net.*; dozC[4mF  
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public class FileSplitterFetch extends Thread { ~z)JO'Z$  

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String sURL; //File URL Bk[C=<
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long nStartPos; //File Snippet Start Position 0+e  
long nEndPos; //File Snippet End Position
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int nThreadID; //Thread's ID sLUOs]cj  
boolean bDownOver = false; //Downing is over 
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boolean bStop = false; //Stop identical +QNsI2t;r  
FileAccessI fileAccessI = null; //File Access interface V!/9GeIF  

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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException bEln.)  
{ o59b#9  
this.sURL = sURL; 54=*vokX_  
this.nStartPos = nStart; }(7TiCwd  
this.nEndPos = nEnd; GSW%~9WBa  
nThreadID = id; sou~m,#  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Jj?HOtaM  
} O]'2<;  
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public void run() iBI->xU[U  
{ Cz &3=),G  
while(nStartPos < nEndPos && !bStop) No`*->R  
{ hZlHY9[t?  
B
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#p"$%f5Q_  
try{ FzNj':D  
URL url = new URL(sURL); t<o7 S:a"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); W^)mz,%x  
httpConnection.setRequestProperty("User-Agent","NetFox"); CK1A$$gnz  
String sProperty = "bytes="+nStartPos+"-"; uehu\umt=  
httpConnection.setRequestProperty("RANGE",sProperty); 5RAhm0Op~.  
Utility.log(sProperty); ^`k;~4'd  
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InputStream input = httpConnection.getInputStream(); 7Mk>`4D'c  
//logResponseHead(httpConnection); #ID fJ2  
) J.xQ}g  
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byte[] b = new byte[1024]; VXW*LEk  
int nRead; `!$6F:d_l  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) (;&}\OX6nm  
{ Q-rG~O9-  
nStartPos += fileAccessI.write(b,0,nRead); g9fYt&  
//if(nThreadID == 1) U8J9 #+:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); lrj&60R`w  
} bv VkN

 
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Utility.log("Thread " + nThreadID + " is over!"); %P D}VF/Y  
bDownOver = true; uVKe?~RC  
//nPos = fileAccessI.write (b,0,nRead); `S0`3q}L3%  
} _QEw=*.<  
catch(Exception e){e.printStackTrace ();} ;|0P\3  
} L_aqr?Q  
} ]YtN6Rq/  
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//打印回应的头信息 l i)6^f#  
public void logResponseHead(HttpURLConnection con) L""ZI5J{F9  
{ J]#rh5um  
for(int i=1;;i++) Z,O*p,Gzn  
{ FzcXSKHV%  
String header=con.getHeaderFieldKey(i); 0|.jIix;  
if(header!=null) ^b$_I31D  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); oyr b.lu/  
Utility.log(header+" : "+con.getHeaderField(header)); Q4_r) &np  
else o$eCd{HuX  
break; ;mT}Q;F#  
} q/@+.q  
} $}{[_2  
Vjs'|%P7  
{kw%7}!  
public void splitterStop() ~\<$H'  
{ _cE_\Ay  
bStop = true; KE ?NQMU  
} G%FZTA6a  
!#:5^":;  
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} #-@Uq6Y  
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/* 3]GMQA{L)  
**FileAccess.java >~nr,V.q  
*//文件访问(定位，写) yvj/u c  
package NetFox; <g%A2lI  
import java.io.*; Ln2FG4{  

/ Ws>;0  
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public class FileAccessI implements Serializable{ u*): D~A  
}6!/Nb  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C#nT@;VO5  
RandomAccessFile oSavedFile; 2.I|8d[  
long nPos; |=*)a2  
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%  
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public FileAccessI() throws IOException "3\y~<8%'  
{ )~)l^0X  
this("",0); nH&z4-1Y?  
} NLY=o@<  
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public FileAccessI(String sName,long nPos) throws IOException ,|s*g'u  
{ A5J41yH  
oSavedFile = new RandomAccessFile(sName,"rw"); v}N\z2A  
this.nPos = nPos; &>C+5`bg  
oSavedFile.seek(nPos); "WuUMt  
} 9Y'pT.Gyb  
'fl< ac,.  
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public synchronized int write(byte[] b,int nStart,int nLen) N-?5[T"  
{ +T@BOYhgq  
int n = -1; Hp04apM:  
try{ s$isDG#Sr  
oSavedFile.write(b,nStart,nLen); Y&j`HO8f  
n = nLen; m9A%Z bQ^  
} 5RN!"YLI3  
catch(IOException e) Y4HN1  
{ #WSqh +  
e.printStackTrace (); RW+
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} I51]+gEN  
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return n; OU/}cu  
} Lm~<BBp.  
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} 0(wu  
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/* sdZ$3oE.  
**SiteInfoBean.java BP@tI|  
*/ P?/JyiO}  
package NetFox; JkWhYP}  
e O\72? K  
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public class SiteInfoBean { Au'y(KB  
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private String sSiteURL; //Site's URL dT*Yv`h  
private String sFilePath; //Saved File's Path H5x7)1Ir|  
private String sFileName; //Saved File's Name Kh\ 7%>K#  
private int nSplitter; //Count of Splited Downloading File UgGa]b[9A  
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public SiteInfoBean() I?}jf?!oM  
{//nSplitter的缺省值为5 ;,[0bmL  
//default value of nSplitter is 5 MGm*({%  
this("","","",5); )1 T2u  
} ]}!@'+=  
iVn4eLK^v  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) `^SRg_rH=`  
{ |T""v_q  
sSiteURL= sURL; 'JMW.;Lh?X  
sFilePath = sPath; *^|\#UIk  
sFileName = sName; ?d-w#<AiV  
this.nSplitter = nSpiltter; BA:x*(%~  
'c7nh{F  
&~P4yI;,  
} 1OMXg=Y  
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uKP4ur@1  
public String getSSiteURL() FSA%,b;U  
{ y<Q"]H.CkQ  
return sSiteURL; uVn"L:_  
} Ahwi  
sWo`dZ\6WB  
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public void setSSiteURL(String value) '-%1ILK$3r  
{ A+RW=|:  
sSiteURL = value; UmWXv#q\l  
} /%& d:  
dR]-R/1|  
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public String getSFilePath() T06(Q[)  
{ Q 84t=  
return sFilePath; (p%|F`  
} pz /[${X  
7?=^0?a  
2/*u$~  
public void setSFilePath(String value) ":udoVS!  
{ `xBoNQai  
sFilePath = value; p3U)J&]c6  
} Rsfb?${0G  
9-c3@>v  
8<C*D".T$  
public String getSFileName() VhkM{O  
{ MT&aH~YB  
return sFileName; |X8?B=  
} [Jt}^  
eT".psRiC  
"sN%S's  
public void setSFileName(String value) $CEdJ+0z  
{ cb9-~*1  
sFileName = value; ?.VKVTX^  
} 4[$:KGh3  
D!o[Sm}JO[  
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public int getNSplitter() 4$KDf;m@  
{ tS2&S 6u  
return nSplitter; M_ukG~/  
} o0R?vnA=  
ur}'Y^0iR  

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public void setNSplitter(int nCount) _&/`-"3y  
{ /^.S nqk  
nSplitter = nCount;  8${n}}  
} ;-Yvi,sS+  
} TWpw/osW  
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S/`#6  
/* ez'NHodwk2  
**Utility.java MV"n{1B  
*/ d%8n  
package NetFox; d-~V.  
wSjDa.?'  
44ty,M3  
public class Utility { _X4Y1zh  
S $p>sItO  
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public Utility() a*cWj}u  
{ cz9J&Le>  
0~ho/_  
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} E#KZZ lbx  
64?HqO 6(  
//线程睡眠 .2E/(VM  
public static void sleep(int nSecond) 0zH-g  
{ R
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try{ -MTk9<qnT  
Thread.sleep(nSecond); F$as#.7FF  
} X hq ss),  
catch(Exception e) H@uu;:l<7A  
{ x2B8G;6u  
e.printStackTrace (); `}?;Ow&2CY  
} QOXo(S  
} 3lp'U&3`5  
jB?SX  
//日志 w.x&3aG  
public static void log(String sMsg) +|LM"  
{ 5C!zEI)  
System.err.println(sMsg); }%u#TwZ  
} D -tRy~}  
K+}0:W=P  
:PT{>r[  
public static void log(int sMsg)
=>;&M)+q  
{ &4-;;h\H  
System.err.println(sMsg); 8 MO-QO  
} +F)-n2Bi  
} ./F:]/Mt  
=5\*Zh1  
%'iJVFF  
/* 1#=9DD$4  
**TestMethod.java h <4`|Bg+  
*/ 'OA*aQ=K  
package NetFox; X}Oe'y  
"QnYT3[l"  
c~vhkRA  
public class TestMethod { %hSQ\T<8[o  
j,j|'7J%  
"TA0--6  
public TestMethod() LaQ7A,]  
{ ///xx/weblogic60b2_win.exe h+W$\T)  
try{ 'f6H#V*C  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); @[g7\d  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 3jAr"xc  
SiteFileFetch fileFetch = new SiteFileFetch(bean); O t)}:oG  
fileFetch.start(); &4:R(]|  
} M(a%Qk?]/  
catch(Exception e){e.printStackTrace ();} Vc9rc}  
%V>%AP  
lI?P_2AaS  
} k'st^1T  
x4* bhiu  
+.!D>U$)}  
public static void main(String[] args) a$=~1@  
{ @s1T|}AJ  
new TestMethod(); 6M >@DRZ'|  
} 4Fft[S(  
} |6Q5bV  
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