http断点续传简单实现（java)

/* 8w L%(p  
**SiteFileFetch.java y-k]Tr  
*/ mYw9lM  
package NetFox; Z!SFJ{  
import java.io.*; H*VZ&{\7  
import java.net.*; ?*: mR|=  
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" UxKG+   
public class SiteFileFetch extends Thread { PR;A 0   
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SiteInfoBean siteInfoBean = null; //文件信息Bean d|RDx;rl8  
long[] nStartPos; //开始位置 ,BuEX#ZaBl  
long[] nEndPos; //结束位置 ebmU~6v k  
FileSplitterFetch[] fileSplitterFetch; //子线程对象  SED_^  
long nFileLength; //文件长度 {*Tnl-m~  
boolean bFirst = true; //是否第一次取文件 L"ob))GF  
boolean bStop = false; //停止标志 ra>jVE0`  
File tmpFile; //文件下载的临时信息 Y.}8lh eH  
DataOutputStream output; //输出到文件的输出流 8zWKKcf7t  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） _tO:,%dL  
public SiteFileFetch(SiteInfoBean bean) throws IOException ("5Eed  
{ 4M{]YZMw8  
siteInfoBean = bean; 5Ff1x-lQ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6O# xV:Uc<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >+E   
if(tmpFile.exists ()) \o2cztl=  
{ =BNS3W6  
bFirst = false; [|
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read_nPos(); BkcA_a:W  
} vivU4:uH3  
else 7PG|e#  
{ ,)](h+zl_6  
nStartPos = new long[bean.getNSplitter()]; MTUJsH\  
nEndPos = new long[bean.getNSplitter()]; V-.Nc#  
} f )K(la^'  
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} 3I%F,-r  
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public void run() Wp0L!X=0  
{ &ytnoj1L(  
//获得文件长度 P]wCC`qi  
//分割文件 6y d/3k  
//实例FileSplitterFetch VGtKW kVH  
//启动FileSplitterFetch线程 lhRo+X#G  
//等待子线程返回 /UAcN1K!B  
try{ Sx|)GTJJ|-  
if(bFirst) ;;;{<GEQ  
{ /ig'p53jL  
nFileLength = getFileSize(); Se>"=[=  
if(nFileLength == -1) Z;4pI@u  
{ }:f \!b  
System.err.println("File Length is not known!"); uxsfQ%3`#  
} &hri4p/  
else if(nFileLength == -2) 5(V'<  
{ tP;^;nw  
System.err.println("File is not access!"); Fo86WP}  
} `PVr;&  
else JZM:R  
{ {:m%n-  
for(int i=0;i<nStartPos.length;i++) c4AkH|  
{ yw3E$~k  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); $&l} ABn  
} 7UzbS,$x  
for(int i=0;i<nEndPos.length-1;i++) FsdxLMwk1  
{ G*x"drP  
nEndPos = nStartPos[i+1]; f#3U,n8:  
} Pm*N!:u  
nEndPos[nEndPos.length-1] = nFileLength; j4hi
MI;  
} fZ)M Dq  
} 5\6S5JyIL  
gPrIu+|F  
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//启动子线程 .tny"a&  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 5C^oqUZ  
for(int i=0;i<nStartPos.length;i++) +zz\*  
{ o;D[F  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Hve'Z,X  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ?h*Ngb
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nStartPos,nEndPos,i); 2kS]:4)T  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !qjIhZi  
fileSplitterFetch.start(); ?z]hYsy  
} RIDzNdM>U  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); (4WAoye|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", G?t<4MTv  
nEndPos = " + nFileLength); snW=9b)m  
// fileSplitterFetch[nPos.length-1].start();
(6*CORE   
5[py{Gq  
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//等待子线程结束 !N@d51T=N  
//int count = 0; {d%% nK~  
//是否结束while循环 JQtBt2  
boolean breakWhile = false; x=%p~$C  
\UF/_'=K  
5/ee&sJR  
while(!bStop) A=z+@b6  
{ %FDv6peH  
write_nPos(); kX2bU$1Q,i  
Utility.sleep(500); z!<X{& e  
breakWhile = true; 0E5
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(zO)J`z>  
for(int i=0;i<nStartPos.length;i++) M!9gOAQP  
{ 4w\@D>@}H  
if(!fileSplitterFetch.bDownOver) m@z.H;  
{ LL}|#%4d  
breakWhile = false; I)B+h8l72<  
break; <h*r  
} E,/<;  
} |\lsTY&2  
if(breakWhile) gNsas:iGM  
break; :?*|Dp1  
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//count++; <yw6Om:n<  
//if(count>4) Y2j>@  
// siteStop(); 3($cBC  
} * 7<{Xbsj^  
-8r';zR  
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System.err.println("文件下载结束！"); w[5uX>  
} #s\HiO$BT  
catch(Exception e){e.printStackTrace ();} e#+u8LrN  
} 8,0WHivg  
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*CIR$sS  
//获得文件长度 CWTPf1?eB  
public long getFileSize() %z0;77[1I  
{ &$1ifG   
int nFileLength = -1; Xiy9Oeq2uh  
try{ ","O8'$OC  
URL url = new URL(siteInfoBean.getSSiteURL()); y*BS %xTF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5Hli@:B2s  
httpConnection.setRequestProperty("User-Agent","NetFox"); J|uxn<E<>  
$j+RUelFY  
4P406,T]r  
int responseCode=httpConnection.getResponseCode(); H'Oy._,]t  
if(responseCode>=400) wb#ZRmx}  
{ %
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processErrorCode(responseCode); <Z nVWER  
return -2; //-2 represent access is error Skbd'j  
} \4/zvlo]h  
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String sHeader; ho'Ihep,L  
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for(int i=1;;i++) ^5MPK@)c,/  
{ ;*H@E(g  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); /S9(rI<'  
//Utility.log(in.readLine()); WRBCNra  
sHeader=httpConnection.getHeaderFieldKey(i); dHzQAqb8J  
if(sHeader!=null) ?g6xy[  
{ }MCh$  
if(sHeader.equals("Content-Length")) -/ltnx)j  
{ ef Moi'v  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); '4"9f]:  
break; '{[n,xeR  
} ,:E*Mw:  
} A"V($:>U  
else XK";-7TZt  
break; L&I8
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} g5YDRL!Wh  
} t1Zcr#b>  
catch(IOException e){e.printStackTrace ();} _x2i=SFo*$  
catch(Exception e){e.printStackTrace ();} -J06H&/k  
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Utility.log(nFileLength); H,{WrWA  
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return nFileLength; mr
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} +D@+j  
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pz hPEp;  
//保存下载信息（文件指针位置） NKSK+ll2  
private void write_nPos() qDVt  
{ OxC8xB;`  
try{ 1Mtm?3Pt  
output = new DataOutputStream(new FileOutputStream(tmpFile)); q
;)+O#CR  
output.writeInt(nStartPos.length); 4ZX6=-u^  
for(int i=0;i<nStartPos.length;i++) QMz6syn4u  
{ t|5T,YFG  
// output.writeLong(nPos); Fcz}Gs4  
output.writeLong(fileSplitterFetch.nStartPos); ^E#i5d+'N  
output.writeLong(fileSplitterFetch.nEndPos); nj(\+l5  
} auai@)v6  
output.close(); 9*<=K  
} ,bGYixIfYZ  
catch(IOException e){e.printStackTrace ();} SJJ[y"GvD  
catch(Exception e){e.printStackTrace ();} O u-/dE%  
} HPus/#j'+  
l(<=JUO;  
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//读取保存的下载信息（文件指针位置） E5+-N  
private void read_nPos() _X6@.sM/2  
{ MV?#g-5  
try{ _-R&A@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ? koIZ  
int nCount = input.readInt(); Tp[-,3L  
nStartPos = new long[nCount]; O!U8"Yr$  
nEndPos = new long[nCount]; _pN:p7l(  
for(int i=0;i<nStartPos.length;i++) N fBH  
{ $[xS>iuD  
nStartPos = input.readLong(); ^Mmsja5K  
nEndPos = input.readLong(); ]=28s *@  
} !K%8tr4  
input.close(); O}3|UI!`  
} 8JFvz(SK>  
catch(IOException e){e.printStackTrace ();} _wp_y-"  
catch(Exception e){e.printStackTrace ();} k E},>+W+  
} lvd`_+P$  
/Pyj|!C3`q  
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private void processErrorCode(int nErrorCode) r?$V;Z  
{ [q!/YL3%  
System.err.println("Error Code : " + nErrorCode); W'Y?X]
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} L']"I^(N  
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//停止文件下载 fWz=bJ"V  
public void siteStop() WXs?2S*  
{ o6/"IIso3  
bStop = true; A:4?Jd>  
for(int i=0;i<nStartPos.length;i++)
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fileSplitterFetch.splitterStop(); rX}FhBl5  
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} 5kik+  
} =1+/`w  
//负责部分文件的抓取 +:kMYL3  
**FileSplitterFetch.java qORL 7?{  
*/ zhgvqg-  
package NetFox; AaLbJYuKd  
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:ggXVwpe  
import java.io.*; 5q;c=oRUj  
import java.net.*; .x'?&7#(  
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public class FileSplitterFetch extends Thread { EYRg,U&'  
?3y>K!D(A  
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String sURL; //File URL Vtv~jJ{m  
long nStartPos; //File Snippet Start Position qH4+iSTnV  
long nEndPos; //File Snippet End Position ^6QzaC3  
int nThreadID; //Thread's ID U'LPaf$O  
boolean bDownOver = false; //Downing is over vcC"  
boolean bStop = false; //Stop identical ~5o2jTNy`p  
FileAccessI fileAccessI = null; //File Access interface tTbfyI  
1T}jK^"  
.#}A/V.-Y  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @:}la  
{ *RmD%[f  
this.sURL = sURL; R0urt  
this.nStartPos = nStart; #x6EZnG  
this.nEndPos = nEnd; uN=f(-"  
nThreadID = id; `Y3\R#  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 n)PqA*  
} *z^Au7,&  
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public void run() ]sI\.a  
{ oDWNOw  
while(nStartPos < nEndPos && !bStop) K7t_Q8  
{ (6i4N2  
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u
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try{ PPde!}T$  
URL url = new URL(sURL); LK<ZF=z]Z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :<v@xOzxx  
httpConnection.setRequestProperty("User-Agent","NetFox"); a@-bw4SD  
String sProperty = "bytes="+nStartPos+"-"; MeYu  
httpConnection.setRequestProperty("RANGE",sProperty); IP^1ca#<  
Utility.log(sProperty); P('bnDU  
 `7oYXk  
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InputStream input = httpConnection.getInputStream(); p^w_-(p  
//logResponseHead(httpConnection); b#*"eZj
 
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byte[] b = new byte[1024]; U,lO{J
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int nRead; _p?s[r*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) PbfgWGr  
{ 2Z?l,M~
  
nStartPos += fileAccessI.write(b,0,nRead); -XnOj2  
//if(nThreadID == 1) BY':
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *J{E1])<a  
} s
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Utility.log("Thread " + nThreadID + " is over!"); Tfx-h)oP3  
bDownOver = true; Ya-GDB;L  
//nPos = fileAccessI.write (b,0,nRead); R,fAl"wMu  
} |pBvy1e4)  
catch(Exception e){e.printStackTrace ();} cqT%6Si  
} Lt i2KY}/%  
} NN5
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//打印回应的头信息 +O)ZB$w4  
public void logResponseHead(HttpURLConnection con) ENI|e,'[  
{ IJC]Al,df  
for(int i=1;;i++) o6:@j#b  
{ v^;vH$B  
String header=con.getHeaderFieldKey(i); &*oljGt8  
if(header!=null) ],vid1E  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ,c 0]r;u!  
Utility.log(header+" : "+con.getHeaderField(header)); c=^69>w  
else hLVgP&/E  
break; J4s`U/F  
} f0YBy<a  
} r%>EiHpCU  
KFy|,@NI  

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public void splitterStop() +{}p(9w@  
{ L">m2/ HG  
bStop = true; uo*lW2&U  
} 1#8~@CQ ::  
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} WI.+9$1:P  
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2sVDv@2  
/* = )4bf"~8  
**FileAccess.java !1@oZ(  
*//文件访问(定位，写) /<dl"PWkJv  
package NetFox; ymT]ow6C  
import java.io.*; &B++ "f  

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)q/
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public class FileAccessI implements Serializable{ 9>ZX@1]m_  
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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 :qV|rih_Q  
RandomAccessFile oSavedFile; XhN?E-WywQ  
long nPos; Ih;D-^RQ  

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+vPCr&40  
public FileAccessI() throws IOException pW>.3pj  
{ l1%*LyD  
this("",0); 5bsv05=e  
} p%/lP{  
IVeA[qA0  
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public FileAccessI(String sName,long nPos) throws IOException Nov An+  
{ Fl"LK:)  
oSavedFile = new RandomAccessFile(sName,"rw"); C\|HN=2eh  
this.nPos = nPos; nE:Wl  
oSavedFile.seek(nPos); 52F3r:Rk  
} M?kXzb\O  
'lgS)m  
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public synchronized int write(byte[] b,int nStart,int nLen) tMo=q7ig  
{ XHY,;4  
int n = -1; eO{2rV45O  
try{ rKl
  
oSavedFile.write(b,nStart,nLen); q\~D:z$+CO  
n = nLen; gV'=uz v  
} ;:bnLSPo  
catch(IOException e) 0_t9;;y :  
{ t,kai6UM  
e.printStackTrace (); s##XC^;p[  
} j3>&Su>H4  
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return n; =C
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} Cn>t"#zs!~  
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} kQrby\F(<  
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;|oem\dKv  
/* l585L3i  
**SiteInfoBean.java CR-2>,*a9  
*/ qc6d,z/  
package NetFox; qi8~bQ{rH  
Pa ^_s  
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public class SiteInfoBean { ^K^rl9  
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`QT9W-0e^  
private String sSiteURL; //Site's URL YRj"]= 5N  
private String sFilePath; //Saved File's Path L0ZAF2O  
private String sFileName; //Saved File's Name _,*QJ  
private int nSplitter; //Count of Splited Downloading File U#4>GO;A  
ul\FZT 4  
IpVtbDW  
public SiteInfoBean() '8|joj>G=  
{//nSplitter的缺省值为5 '^.3}N{Fo  
//default value of nSplitter is 5 RNX>I,2sh  
this("","","",5); ~Ecx>f4nX  
} <{.pYrn  
!:1BuiL  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7nbaR~ZV  
{ N\x<'P4q  
sSiteURL= sURL; OC`Mzf%.  
sFilePath = sPath; ,^qHl+'  
sFileName = sName; @Sz7*p  
this.nSplitter = nSpiltter; *YTv"  
7*47mJyc  
v0+$d\mP4<  
} 2%j"E{J&  
m>'#664q1  
kT&GsR/  
public String getSSiteURL() .c_qMTm"  
{ MN
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return sSiteURL; a.SxMF  
} !A"-9OS2  
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public void setSSiteURL(String value) [3(lk_t  
{ ]U5/!e  
sSiteURL = value; e:=+~F(f  
} E^V4O l<  
6Xt c3  
] U[4r9V  
public String getSFilePath() +K"d\<  
{ ngH_p>  
return sFilePath; t8"yAYj  
} 6?3\P>`3Y  
fMRMQR=6B  
w0fFm"A|W  
public void setSFilePath(String value) stlkt>9  
{ /??nOVvt  
sFilePath = value; CrEC@5j  
} UQ+!P<>w   
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(hIy31Pf  
public String getSFileName() k!sk\~>YO  
{ -<aN$O  
return sFileName; .
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} + Scw;gO  
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i^&^eg'.5  
public void setSFileName(String value) J, vEZT<Mt  
{ +:m'  
sFileName = value; !"N-To-c  
} _.3O(?p,  
Y+_t50S  
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public int getNSplitter() vrvOPLiQ  
{ M\dZxhQ-l  
return nSplitter; x8E!Ko](  
} Fs;_z9ej-u  
hZLwg7X!  
p*"H&xA@  
public void setNSplitter(int nCount) `'M}.q,k~  
{ eEMU,zCl  
nSplitter = nCount; Kv-4VWh  
} *9xv0hRQ%?  
} ayoqitXD?  
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h;2n2.Q  
/* ld/\`s[i  
**Utility.java $&[}+??  
*/ UBvea(z-#  
package NetFox; ;]xJC j  
#&ZwQw  
V.Ki$0
>  
public class Utility { E]j2%}6Z%  
]-G10p}Ph-  
V50FX}i  
public Utility() i$!-mYi+Q!  
{ *T{P^q.s~[  
BX=YS)  
U<H< !NV  
} %>Y86>mVz  
j^'op|l  
//线程睡眠 ;OynkZs)  
public static void sleep(int nSecond) V[T`I a\  
{ QvN=<V  
try{ pv #uLo  
Thread.sleep(nSecond); O4i5fVy{  
} 7Ta",S@m  
catch(Exception e) 1rmK#ld"=Z  
{ L+o"<LV]  
e.printStackTrace (); k9pOY]_Y  
} '8b/TL  
} DHlCus=ic  
7$&3(#!N  
//日志 OPsg3pW!]  
public static void log(String sMsg) ` kG}NJf  
{ b;XUv4~V  
System.err.println(sMsg); 8V$:th('  
} aOH$}QnS  
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ZfYva(zP{Q  
public static void log(int sMsg) "Wz#<! .r  
{ 
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System.err.println(sMsg); H=j&uv8  
} - s,M+Q(<  
} sw'?&:<"Ow  
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gI SP .  
/* 6.!Cm$l  
**TestMethod.java =
UT^5cl(  
*/ l"#}g%E  
package NetFox; feH|sz`e  
30fsVwE2  
l12_&o"C~  
public class TestMethod { y,D4b6  
D/ SM/  
e)WpqaI  
public TestMethod() Q8kdX6NMd&  
{ ///xx/weblogic60b2_win.exe ?{OB+f}Mo  
try{ c3>#.NP_  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); VQQtxHTC3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 61W ms@D%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =&J7 'nDP  
fileFetch.start(); ]}~[2k.  
} _'yN4>=6u  
catch(Exception e){e.printStackTrace ();} q-g3!  
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7eh<>X!T
X  
} *P#okwp  
#Tjv(O[&  
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public static void main(String[] args) B4yC"55  
{ i9qn_/<c  
new TestMethod(); wIv_Z^%V  
} u7oHqo`  
} l.#iMi(@p~  
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