http断点续传简单实现（java)

/* T~Gvp0r}h  
**SiteFileFetch.java X4 A<[&F/  
*/ -(f)6a+H  
package NetFox; zmSUw}-4N  
import java.io.*; ~c %hWt  
import java.net.*; p$PKa.Y3  
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public class SiteFileFetch extends Thread { EUN81F?  
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SiteInfoBean siteInfoBean = null; //文件信息Bean (]Y 5eM  
long[] nStartPos; //开始位置 !V i@1E  
long[] nEndPos; //结束位置 my4giC2a  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?TU}~}  
long nFileLength; //文件长度 ] :BX!<  
boolean bFirst = true; //是否第一次取文件 `Ye\p6v!+  
boolean bStop = false; //停止标志 o1FF"tLkN  
File tmpFile; //文件下载的临时信息 @U3Vc|  
DataOutputStream output; //输出到文件的输出流 E ,|xJjh  
(`sH3&Kl  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） `kZ@Zmj#  
public SiteFileFetch(SiteInfoBean bean) throws IOException E#ul IgD  
{ eC[$B99\  
siteInfoBean = bean; oAPb*;}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); $!8-? ?ML  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^(|vsFz
n  
if(tmpFile.exists ()) Re
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{ Db;G@#x  
bFirst = false; MD|5 ol9  
read_nPos(); rmE"rf  
} .)<(Oj|4  
else ~:3QBMk::  
{ lJE93rXU  
nStartPos = new long[bean.getNSplitter()]; YEj8S5"Su\  
nEndPos = new long[bean.getNSplitter()]; 0IfKJ*]M  
} u"d~!j1  
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} }jVSlCF@t  
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public void run() @ ]/AjjLt  
{
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//获得文件长度 R +WP0&d'  
//分割文件 zJ)*Z,7  
//实例FileSplitterFetch =9"W@n[>W  
//启动FileSplitterFetch线程 AiK  
//等待子线程返回 ;ByOth|9P  
try{ k&.Jk B"  
if(bFirst) N9vP7  
{ qHP78&wUx  
nFileLength = getFileSize(); yq NzdzX  
if(nFileLength == -1) l?Fb ='#  
{ bIEhgiH  
System.err.println("File Length is not known!"); r%.do;5  
} iTV) NsC}  
else if(nFileLength == -2) Xa[?^P  
{ =<NljOR4`  
System.err.println("File is not access!"); ijdXU8  
} .?!N^_ Ez3  
else ?HV`| Cw  
{ I<8sI%,s  
for(int i=0;i<nStartPos.length;i++) Ce")[<:  
{ K%X^n>O7C  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); yNqe8C,>e  
} [g Z"a*  
for(int i=0;i<nEndPos.length-1;i++) |R#"Th6mH!  
{ vJU*>U,  
nEndPos = nStartPos[i+1]; jD`d#R  
} K%Rj8J7|u?  
nEndPos[nEndPos.length-1] = nFileLength; ~DsECnD  
} BZXUwqEh  
} ?w+Ix~k  
4|`Bq}sjZf  
8-Hsgf.*  
//启动子线程 wu4NLgkE  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2d {y M(=(  
for(int i=0;i<nStartPos.length;i++) QEu=-7@>  
{ |-CnT:|o  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,s_T pq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), W":PG68  
nStartPos,nEndPos,i); S>0nx ^P  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j* *s^Sg  
fileSplitterFetch.start(); =07]z@s  
} <6G11-K  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D K
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); s9>(Jzcf9  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4j!]:ra  
nEndPos = " + nFileLength); [F[K^xYTlg  
// fileSplitterFetch[nPos.length-1].start(); 1 `7<2w  
4 8{vE3JY  
o8Z[+;  
//等待子线程结束 d.2mT?`#  
//int count = 0; /^ " 83?_  
//是否结束while循环 ZJjTzEV%^B  
boolean breakWhile = false; rJo"fx  
_6Eu2|vM&  
//&j<vus  
while(!bStop) gXH[$guf  
{ 0ilCS[`b  
write_nPos(); >2?aZ`r+  
Utility.sleep(500); i#%a-I:
M  
breakWhile = true; > QFHm5Jw  
/n4pXT  
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for(int i=0;i<nStartPos.length;i++) '>v^6iS  
{ iHp\o=#  
if(!fileSplitterFetch.bDownOver) 0gn@h/F2%  
{ )){xlFA}  
breakWhile = false; 6UE(f@  
break; Xm4CKuU@  
} `PL[lP-<  
} 8:.nEo'  
if(breakWhile) jb /8?7  
break; T|"7sPgGR  
xc?}TPpt  
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//count++; z\/53Sy<  
//if(count>4) J@9}`y=K  
// siteStop(); k?VQi5M  
} !?[oIQ)h  
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System.err.println("文件下载结束！"); f'6|OsVQ  
} jvzBh-!  
catch(Exception e){e.printStackTrace ();} gNx+>h`AF  
} :ZxLJK9x1  
\nqo%5XL  
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//获得文件长度 r?
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public long getFileSize() M@p"yq  
{ ^t[HoFRa  
int nFileLength = -1; Vj; vo`T  
try{ #\bP7a+  
URL url = new URL(siteInfoBean.getSSiteURL()); dZ:r&Qa  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ODf4+& u  
httpConnection.setRequestProperty("User-Agent","NetFox"); cbKL$|  
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int responseCode=httpConnection.getResponseCode(); S:Tm23pe  
if(responseCode>=400) Wn!G.(Jq  
{ F?Or;p5`Y  
processErrorCode(responseCode); %B EC] h  
return -2; //-2 represent access is error # nfI%  
} |ia@,*KD  
iilyw_$H  
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String sHeader; !W1eUY  
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for(int i=1;;i++) i#,1iVSG  
{ Q:S\0cI0  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ZHy><=2  
//Utility.log(in.readLine()); =sQ(iso%f  
sHeader=httpConnection.getHeaderFieldKey(i); 7unA"9=[4V  
if(sHeader!=null) gwQvao  
{ 7dD.G/'  
if(sHeader.equals("Content-Length")) "@/ba!L+  
{ |l90g|is
J  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); I$N7pobh  
break; 5_G'68;OV  
} ,0T)Oc|HL/  
} ]+IVSxa!u  
else #t5juX9Ho9  
break; |vy]8?Ak  
} v#=ayWgk  
} + x_wYv  
catch(IOException e){e.printStackTrace ();} ?;8M^a/  
catch(Exception e){e.printStackTrace ();} ,o&<WMD  
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Utility.log(nFileLength); f-vK}'Z`,  
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return nFileLength; EHWv3sR-  
} zXgkcq)  
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 3Vu8F"  
//保存下载信息（文件指针位置） jI#z/a!j:  
private void write_nPos() --/-D5  
{ ew"m!F#  
try{ 9&(.x8d,a  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7sN0`7  
output.writeInt(nStartPos.length); 7S2c|U4IM  
for(int i=0;i<nStartPos.length;i++) Q}z{AZ  
{ SbJh(V-pr  
// output.writeLong(nPos); ZX]
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output.writeLong(fileSplitterFetch.nStartPos); ^=#!D[xj>  
output.writeLong(fileSplitterFetch.nEndPos); 8AX3C s_G  
} J]]\&MtaO  
output.close(); %f#\i#G<k  
} n@o  
catch(IOException e){e.printStackTrace ();} W["HDR  
catch(Exception e){e.printStackTrace ();} HtS#_y%(  
} DsG !S*  
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+TW
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//读取保存的下载信息（文件指针位置） ,"C&v~  
private void read_nPos() `0[fLEm  
{ -sD:+Te  
try{ bF7`] 83  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); mlmnkgl ]  
int nCount = input.readInt(); h?3f5G*&H  
nStartPos = new long[nCount]; fX$6;Ae  
nEndPos = new long[nCount]; !?Tzk&'  
for(int i=0;i<nStartPos.length;i++) @hBx,`H^  
{ J b|mXNcL  
nStartPos = input.readLong(); s!=!A  
nEndPos = input.readLong(); s~#
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} @nW'(x(  
input.close(); >0ssza  
} ),z,LU Yf  
catch(IOException e){e.printStackTrace ();} d OzO/w&  
catch(Exception e){e.printStackTrace ();} 6l=M;B7:i  
} u'{sB5_H  
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private void processErrorCode(int nErrorCode) 8g&uE*7N  
{ R2'C s  
System.err.println("Error Code : " + nErrorCode); #NSaY+V  
} w2s,  
"P9wT)J_  
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//停止文件下载 69[w/\  
public void siteStop() aj% `x4eA  
{ &Qz"nCvJ  
bStop = true; p3i qW,[@  
for(int i=0;i<nStartPos.length;i++) 2I9{
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fileSplitterFetch.splitterStop(); !<JG&9ODP  
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} Nj"_sA p  
} !NQf< ch  
//负责部分文件的抓取  W\zL  
**FileSplitterFetch.java p=je"{  
*/ "
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package NetFox; Bx_8@+  
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import java.io.*; U*c{:K-C  
import java.net.*; J:k@U42  
(*c`<|)  
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public class FileSplitterFetch extends Thread { 9e|{z9z[l  
as\)S?0`.  
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String sURL; //File URL qugPs(uQ  
long nStartPos; //File Snippet Start Position 4l#T_y  
long nEndPos; //File Snippet End Position U{.+*e18  
int nThreadID; //Thread's ID cPa 0n4  
boolean bDownOver = false; //Downing is over ` Mv5!H5l  
boolean bStop = false; //Stop identical mw%[qeLV  
FileAccessI fileAccessI = null; //File Access interface co(fGp#!  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ({}O M=_  
{ *
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this.sURL = sURL; }(hYG"5  
this.nStartPos = nStart; E2ayK> ,  
this.nEndPos = nEnd; A,A-5l<h]?  
nThreadID = id; g~WNL^GGS  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Xk7$?8r4&  
} n=Z[w5  
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public void run() IU;pkgBj0Y  
{ PK|`}z9  
while(nStartPos < nEndPos && !bStop) LQ&d|giA  
{ ;zxlwdfcr'  
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try{ \c@qtIc  
URL url = new URL(sURL); QP-<$P;~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =.=. \K  
httpConnection.setRequestProperty("User-Agent","NetFox"); OYRR'X.E  
String sProperty = "bytes="+nStartPos+"-"; K]=>F  
httpConnection.setRequestProperty("RANGE",sProperty); &#EVE xL  
Utility.log(sProperty); PezWc18  
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InputStream input = httpConnection.getInputStream(); ,LW%'tQ~"  
//logResponseHead(httpConnection); 5['B- Iw  
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byte[] b = new byte[1024]; MZ+IorZl  
int nRead; RU ,N_GV
 
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Q; /!oA_  
{ e4_aKuA  
nStartPos += fileAccessI.write(b,0,nRead); =)UiI3xHk  
//if(nThreadID == 1) 8GAQVe^$-  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `"-!UkD+  
} X52jqXjg  
fkUH]CdaB  
Q Fqv,B\<  
Utility.log("Thread " + nThreadID + " is over!"); R*5;J`TW  
bDownOver = true; ~q%9zO'  
//nPos = fileAccessI.write (b,0,nRead); QNI|h;D  
} X}QmeY[0I  
catch(Exception e){e.printStackTrace ();}  DlkKQ  
} bb_jD^  
} <!nWiwv  
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3jdB8a]T_  
//打印回应的头信息 z00:59M4  
public void logResponseHead(HttpURLConnection con) 4J$f @6  
{ '\mZ7.Jj  
for(int i=1;;i++) I; }%k;v6  
{ 3\.)y49,1  
String header=con.getHeaderFieldKey(i); umrI4.1c  
if(header!=null) >2{HH\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); P FFw$\j  
Utility.log(header+" : "+con.getHeaderField(header)); 8GZjIW*0oq  
else KKXb,/  
break; M!XFb  
} y#0Z[[I0  
} '\YhRU  
")gCA:1-  
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public void splitterStop() nhhJUN?8  
{ s;f u  
bStop = true; =w?cp}HW  
} E4ee_`p  
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} _[tBLGXD  
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u"|nu!p`  
/* $iJ #%&D  
**FileAccess.java "G)? E|  
*//文件访问(定位，写) FMr$cKvE]W  
package NetFox; jC8BLyGE_  
import java.io.*; yYtki  
UzwIV{  
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public class FileAccessI implements Serializable{ 9:~^KQ{?  
sB!A:  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 4"=pcHNV  
RandomAccessFile oSavedFile; $MGd>3%y  
long nPos; Z28@yD+  
:
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public FileAccessI() throws IOException C`K/ai{4  
{ ^jA^~h3(W  
this("",0); [%q":I
g  
} 4TV9t"Dk+c  
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public FileAccessI(String sName,long nPos) throws IOException Yuck]?#0  
{ 0\A[a4crj  
oSavedFile = new RandomAccessFile(sName,"rw"); r]{:{Z  
this.nPos = nPos; ~Q\[b%>J  
oSavedFile.seek(nPos); 4Qs#ws])  
} [rem,i+  
_uacpN/<|  
fN;
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public synchronized int write(byte[] b,int nStart,int nLen) 1+zax*gO-  
{ qr1^i1%\  
int n = -1; 5@\<:Zmi  
try{ S7]cF5N  
oSavedFile.write(b,nStart,nLen); Ns{4BM6j  
n = nLen; cA,xf@itp  
} N0NMRU]zT  
catch(IOException e) A,@"(3  
{ r\?*?sL  
e.printStackTrace (); M_Dk
juR  
} 8[V!e[  
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return n; z Ey&%Ok  
} 
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} wlJ_,wA  
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/* ]d0Dd")n  
**SiteInfoBean.java ;
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*/ Al?XJ C B@  
package NetFox; Wp ]u0w  
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public class SiteInfoBean { 6%>0g^`)9Y  
]pb3 Fm{  
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private String sSiteURL; //Site's URL yTk9+>  
private String sFilePath; //Saved File's Path ZD*>i=S  
private String sFileName; //Saved File's Name K%;O$ >  
private int nSplitter; //Count of Splited Downloading File AdhCC13B  
V6c?aZ,O  
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public SiteInfoBean() ~96"^%D  
{//nSplitter的缺省值为5 HHdc[pJ0D  
//default value of nSplitter is 5 >Kxl+F  
this("","","",5); B$HQFdTli  
} j \SDw  
kb>9;-%^JK  
E:7vm@+  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) f!87JE=<  
{ m<j ^cU#J  
sSiteURL= sURL; L\"$R":3{d  
sFilePath = sPath; s;A]GJ  
sFileName = sName; Wd[XQZ<  
this.nSplitter = nSpiltter; E;N+B34  
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0FXM4YcrJO  
} f+d{^-  
0KEytm]  
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public String getSSiteURL() "~GudK &  
{ %o~zsIl  
return sSiteURL; JjM^\LwKkL  
} vWow^g  
L%fWa2P'  
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public void setSSiteURL(String value) %e_WO,R  
{ KExfa4W 3{  
sSiteURL = value; (33[N  
} YTY0N5["  
DD;PmIW  
2t_E\W7w+  
public String getSFilePath() +1e*>jE  
{ rBpr1XKl,  
return sFilePath; Xa-]+_?Q  
} csYICLj  
fz<Y9h=  

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public void setSFilePath(String value) zS.7O'I<'  
{ >GqIpfn  
sFilePath = value; G.L4l|%W  
} -6#i~a]  
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public String getSFileName() CKj3-rcF(  
{ 6?2/b`k  
return sFileName; x}72jJe`  
} L{aT"Of{X  
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t'~:me!  
public void setSFileName(String value) 0!xD
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{ ^1}}-9q  
sFileName = value; \\)3:1X  
} tBdvk>d  
O=ci"2!\-  
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public int getNSplitter() 7M5HIK6_  
{ ;sb0,2YyP  
return nSplitter; :Ruj;j  
} HnZrRHT0  
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<#sB ;  
public void setNSplitter(int nCount) ePB=aCZ  
{ 4{*K%p
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nSplitter = nCount; 2x'JR yef  
} d
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} luAhyEp  
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/* ,NKDEcw]  
**Utility.java  XW`&1qx  
*/ Fpl<2eBg4  
package NetFox; H#G'q_uHH  
9 bGN5.5  
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public class Utility { J1&G1\G|s=  
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public Utility() ]@>bz
  
{ :!J!l u  
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} &`0heJ 5Yn  
!Vv$  
//线程睡眠 cMIQbBM  
public static void sleep(int nSecond) M*{EK  
{ L0_R2EA  
try{ 315Rk!{AJ  
Thread.sleep(nSecond); OT\[qaK  
} xsV(xk4  
catch(Exception e) Ga"$_DyM  
{ k g0Z(T:&8  
e.printStackTrace (); p8Ts5n  
} \P+lb-~\"  
} 7-Fh!=\f/  
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//日志 S_ e }>-  
public static void log(String sMsg) ^+E
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{ 9=K=gfZ  
System.err.println(sMsg); 5<Xq7|Jt  
} Ik(TII_  
km4::'(6  
=uIu0_v  
public static void log(int sMsg) zgJ%Zr!~  
{ Y_xPr%%A  
System.err.println(sMsg); wBA[L}   
} w*f.Fu(su  
} ,ZC^,Vq  
m("! M~1  
bH~ue5q  
/* 7fgA)dU:K  
**TestMethod.java $7T
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*/ MrXhVZ"d*  
package NetFox; 7eqax33f  
+q|2j>k@  
n[[rI0]g  
public class TestMethod { ,9`sC8w|  
"nf.kj:>  
+>@<'YI<  
public TestMethod() +3(1QgYM%  
{ ///xx/weblogic60b2_win.exe #e((F,1z  
try{ weEmUw Z  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); x24  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5P,{h  
SiteFileFetch fileFetch = new SiteFileFetch(bean); k+f!)7_  
fileFetch.start(); c6:"5};_  
} jV;&*4if  
catch(Exception e){e.printStackTrace ();} <iajtq<Z  
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} U+3,(O  
2M3.xUS  
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public static void main(String[] args) : |#Iw  
{ p6$ QTx  
new TestMethod(); ,^3eMn  
} "2o,X
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} qPK3"fzH  
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