http断点续传简单实现（java)

/* 3q[WHwmm  
**SiteFileFetch.java WnFG{S{s  
*/ NIr@R7MKd  
package NetFox; Bc-yxjsw  
import java.io.*; SZ![%)83  
import java.net.*; S/vf'g
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public class SiteFileFetch extends Thread { b<I9 MR  
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SiteInfoBean siteInfoBean = null; //文件信息Bean j Ib  
long[] nStartPos; //开始位置 DH DZ_t:  
long[] nEndPos; //结束位置 eg"Gjp-4=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _zxLwU1(x  
long nFileLength; //文件长度 ulHn#)  
boolean bFirst = true; //是否第一次取文件 8 S`9dSc  
boolean bStop = false; //停止标志 .N4  
File tmpFile; //文件下载的临时信息 .UCt|> $  
DataOutputStream output; //输出到文件的输出流 ER2GjZa\z  
V5"CSMe  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） NY$uq+Z>  
public SiteFileFetch(SiteInfoBean bean) throws IOException "i.r@<)S  
{ 9_ICNG%  
siteInfoBean = bean; M/PFPJ >`  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9n]|PE
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); p5=|Y^g !  
if(tmpFile.exists ()) ?8dVH2W.  
{ pZZgIw}aS  
bFirst = false; hli|B+:m"  
read_nPos(); Oh.ZPG=  
} *x~xWg9^  
else 1RLY $M  
{ WlB'YL-`g  
nStartPos = new long[bean.getNSplitter()]; Y-piL8Xc  
nEndPos = new long[bean.getNSplitter()]; Ou
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} q+SD6qM  
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} X C86-b)E  
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public void run() C;AA/4Ib  
{ _s,ao'/  
//获得文件长度 wo2@hav  
//分割文件 `i,_aFB|  
//实例FileSplitterFetch )|j[uh6wo  
//启动FileSplitterFetch线程 v4Zb? Yb  
//等待子线程返回 }g+;y  
try{ &ej8mq"\  
if(bFirst) 3>ex5  
{ ] U@o0  
nFileLength = getFileSize(); W^,S6!  
if(nFileLength == -1) }*]B-\>  
{ v1U?&C  
System.err.println("File Length is not known!"); )/ Ud^wi  
} |s7`F%  
else if(nFileLength == -2) )'4P.>!!aQ  
{ rsn.4P=  
System.err.println("File is not access!"); (w(  
} RhI;;
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else psh^MX)Q  
{ yZ]:y-1  
for(int i=0;i<nStartPos.length;i++) RT/o$$  
{ oq/G`{`\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); gC%G;-gm  
} Agh`]XQ2  
for(int i=0;i<nEndPos.length-1;i++) 4nfu6Dq  
{ aIy*pmpD=  
nEndPos = nStartPos[i+1]; kB:Uu}(=N  
} S 6,4PP  
nEndPos[nEndPos.length-1] = nFileLength;
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} Z#d&|5Xj  
} # M,
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//启动子线程 Jo(`zuLJ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Zv]x'3J#Y  
for(int i=0;i<nStartPos.length;i++) <>xJn{f0c  
{ -Lu)'+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %m,6}yt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ha@L94Lq  
nStartPos,nEndPos,i); @tohNO>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); KT|R
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fileSplitterFetch.start(); mpC`Yk  
} Ok5<TZ6t4k  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M4LP$N  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;rI@*An  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5V[oE\B  
nEndPos = " + nFileLength); ulT8lw='  
// fileSplitterFetch[nPos.length-1].start(); 2=0DCF;Bv  
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//等待子线程结束 \?>Hu v  
//int count = 0; @5
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//是否结束while循环 'X).y1'  
boolean breakWhile = false; 0<"k8 k@J  
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while(!bStop) c5q9LQ/  
{ "]'?a$\ky:  
write_nPos(); 8bK|:B#6,  
Utility.sleep(500); _$NIp `d  
breakWhile = true; q>f<u&  
(z7vl~D  
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for(int i=0;i<nStartPos.length;i++) y4Z&@,_{  
{ $CTSnlPq  
if(!fileSplitterFetch.bDownOver) *b *G2f^  
{ 682Z}"I0  
breakWhile = false; eg<bi@C1|  
break; \}6;Kf}\  
} 3<=,1 cU  
} spU)]4P&  
if(breakWhile) 0tISXu-  
break; d\MLOXnLq;  
` 8W*  
lPH%Do>K  
//count++; 2Y}?P+:%>  
//if(count>4) h'J|K^na  
// siteStop(); !f>d_RG  
} Y^Nuz/  
]3
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r
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System.err.println("文件下载结束！"); ?1L
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}  [=O/1T  
catch(Exception e){e.printStackTrace ();} )}Q(Tl\$  
} Gir#"5F  
=U[3PC-N@  
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//获得文件长度 Z UKf`m[  
public long getFileSize() g71[6<D  
{ rG?>
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int nFileLength = -1; mOo`ZcTU  
try{ pY4}>ju(g  
URL url = new URL(siteInfoBean.getSSiteURL()); ]&Z))H  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); d@w~[b  
httpConnection.setRequestProperty("User-Agent","NetFox"); yJuQ8+vgR}  
z"D.Bm~]  
tH=
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int responseCode=httpConnection.getResponseCode(); ,Vd\m"K{  
if(responseCode>=400) b[z]CP  
{ fA'qd.{f^
 
processErrorCode(responseCode); 2._X|~0a  
return -2; //-2 represent access is error JvYPC  
} !8 &=y  
T5urZq*R  
+% /s*EC'w  
String sHeader; 0CSv10Tg  
Iff9'TE  
'65LKD  
for(int i=1;;i++) ~HQ9i%exg  
{ ntNI]~z&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); R1&unm0  
//Utility.log(in.readLine()); f= >OJ!:  
sHeader=httpConnection.getHeaderFieldKey(i); (SSRY9  
if(sHeader!=null) N@B9 @8h  
{ r"$.4@gc  
if(sHeader.equals("Content-Length")) .xf<=ep  
{ [c_|ob]  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); E{6~oZ#L  
break; (}.@b|s  
} Y
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} <2C7<7{7  
else A!1
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break; rt JtK6t  
} H>r!i4l  
} 0G!]=  
catch(IOException e){e.printStackTrace ();} 9rh}1eo7  
catch(Exception e){e.printStackTrace ();} hdTzCfeZ5@  
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Utility.log(nFileLength); iy""(c  
:JlP[I  
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return nFileLength; JNcYJ[wqv  
} VDTcR  
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>u9Nz0?j  
//保存下载信息（文件指针位置） tabT0  
private void write_nPos() P%K4[c W~  
{ Wg`R_>qQSm  
try{ ZiLj=bh  
output = new DataOutputStream(new FileOutputStream(tmpFile)); o1nURJ!  
output.writeInt(nStartPos.length); (8_\^jJ  
for(int i=0;i<nStartPos.length;i++) h6dPO"  
{ Y^<bl2"y8  
// output.writeLong(nPos); +{
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output.writeLong(fileSplitterFetch.nStartPos); s/089jlc  
output.writeLong(fileSplitterFetch.nEndPos); )O:0]=#))  
} 26CS6(sn  
output.close(); 6(PM'@i  
} 0'nikLaKy  
catch(IOException e){e.printStackTrace ();} tHLrhH<w  
catch(Exception e){e.printStackTrace ();} &/,|+U[  
} \9-"M;R.d  
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//读取保存的下载信息（文件指针位置） C]Q8:6b  
private void read_nPos() ^*fQX1h<  
{ vloF::1  
try{ ftH:r_"O#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); KZPEG!-5  
int nCount = input.readInt(); B=|cS;bM$3  
nStartPos = new long[nCount]; X$/2[o#g  
nEndPos = new long[nCount]; dH
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for(int i=0;i<nStartPos.length;i++) NHlk|Y#6b  
{ uslQ*7S[^  
nStartPos = input.readLong(); +}jJ&Z9)  
nEndPos = input.readLong(); Xr
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} V)}rEX  
input.close(); v%Wx4v@%SE  
} ,AT[@  
catch(IOException e){e.printStackTrace ();} (p%>j0<  
catch(Exception e){e.printStackTrace ();} +{
/  
} g}]t[}s1]  
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private void processErrorCode(int nErrorCode) HV<Lf 6gE  
{ 1'?4m0W1  
System.err.println("Error Code : " + nErrorCode); R:B^  
} qe5feky  
J=/5}u_gw  
*2jK#9"MP  
//停止文件下载 r&FDEBh  
public void siteStop() Yw0[[N<SW  
{ Ewg:HX7<(  
bStop = true; R##~*>#  
for(int i=0;i<nStartPos.length;i++) mc4i@<_
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fileSplitterFetch.splitterStop(); %.Q !oYehj  
{z|;Xi::"  
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} 5ZBKRu  
} H/}]FmjN  
//负责部分文件的抓取 NVRLrJWpp  
**FileSplitterFetch.java u]OW8rc  
*/ kZ"BBJ6w  
package NetFox; R LD`O9#j  
Z(Jt~a3o  
n?V+dC=F}  
import java.io.*; -lv)tHs<  
import java.net.*; K$d$m <  
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public class FileSplitterFetch extends Thread {
0]4(:(B  

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String sURL; //File URL 63A}TBC  
long nStartPos; //File Snippet Start Position }u1O#L}F5  
long nEndPos; //File Snippet End Position Vx-7\NB  
int nThreadID; //Thread's ID =G]@+e  
boolean bDownOver = false; //Downing is over Dih3}X&jn$  
boolean bStop = false; //Stop identical {AQ=<RDRF  
FileAccessI fileAccessI = null; //File Access interface #Qkroji qw  

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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException A<ynIs<  
{ G$sA`<<  
this.sURL = sURL; 71l%MH  
this.nStartPos = nStart; TiH)5  
this.nEndPos = nEnd; b5^OQH{v  
nThreadID = id; )5 R=Z<  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 k?7 X3/O  
}
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e
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public void run() t]e;;q=L.  
{ 0#MqD[U(  
while(nStartPos < nEndPos && !bStop) //aF5:Y#  
{ Gw1@KKg  
:Lz\yARpk  
F;>!&[h}G  
try{ ."Y e\>k  
URL url = new URL(sURL); bwl|0"f+`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); gmm.{%1_I;  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?^N3&ukkyo  
String sProperty = "bytes="+nStartPos+"-"; O]m+u  
httpConnection.setRequestProperty("RANGE",sProperty); 'g{9@PkGn  
Utility.log(sProperty); 7sXxq4  
> %KuNy{  
+}a ]GTBgA  
InputStream input = httpConnection.getInputStream(); {*ob_oc  
//logResponseHead(httpConnection); znHnVYll(  
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xL" |)A =  
byte[] b = new byte[1024]; I&YSQK:b  
int nRead; :GJ &_YHf  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) F,'exuZ  
{ b3VS\[p  
nStartPos += fileAccessI.write(b,0,nRead); -! K-Htb-  
//if(nThreadID == 1) /S lYm-uQ+  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1PatH[T[  
} {,L+1h  
jkvg
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Utility.log("Thread " + nThreadID + " is over!"); nb>7UN.9  
bDownOver = true; ivz{L-  
//nPos = fileAccessI.write (b,0,nRead); -(bkr+N  
} 9rA=pH%<>B  
catch(Exception e){e.printStackTrace ();} 1u9LdkhnY  
} p"U,G -_  
} <=,6p>Eo[  
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//打印回应的头信息 [#sz WNfU  
public void logResponseHead(HttpURLConnection con) L~KM=[cn  
{ `F>O;>i''  
for(int i=1;;i++) fX|Y;S-@+  
{ >_LDMs[-p  
String header=con.getHeaderFieldKey(i); Tq4-wE+  
if(header!=null) W='>:H  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ,#kIr  
Utility.log(header+" : "+con.getHeaderField(header)); pt}X>ph{  
else WH\))y-  
break; VzKW:St  
} 10U9ZC  
} Qg<(u?7N  
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lO_UPC\@fw  
public void splitterStop() %p0xM  
{ {qa Aq%'  
bStop = true; UMcgdJB  
} z.I9wQ]X[  
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} yiA<,!;4P  
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,xxR\}  
/* 9\DQ>V TQ  
**FileAccess.java `9b7>Nn<  
*//文件访问(定位，写) `kJ^zw+  
package NetFox; `{xNXH]@  
import java.io.*; +o51x'Ld*  
Ht4;5?/y  
5kz)5,KjM  
public class FileAccessI implements Serializable{ ,c)uX#1  
4%3Mb-#Y]  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 E2{FK)qT  
RandomAccessFile oSavedFile;  ({=gw9f  
long nPos; ;/rXQe1  
I}vmU^Y>  
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public FileAccessI() throws IOException qm8&*UuKJ  
{ +@/"%9w
 
this("",0); GHeVp/u  
} se>MQM5 )  
'&|=0TDd+  
_Iv6pNd/  
public FileAccessI(String sName,long nPos) throws IOException %$Aqle[  
{ heK7pH7;d  
oSavedFile = new RandomAccessFile(sName,"rw"); n;T7=1_"  
this.nPos = nPos; AlIpsJ[UU  
oSavedFile.seek(nPos); ut I"\1hQ  
} Aj4T"^fv  
UTH_^HAN#G  
|Xk4&sDrK  
public synchronized int write(byte[] b,int nStart,int nLen) HZf/CE9T  
{ '4#}e[e  
int n = -1; jYhB +|  
try{ L-k@-)98  
oSavedFile.write(b,nStart,nLen); ynhmMy%  
n = nLen; V:c;-)(  
} N D2L_!g:(  
catch(IOException e) H?X|(r|+  
{ <>aw 1WM+  
e.printStackTrace (); fk x \=  
} a,WICv0E  
L');!/:  
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return n; AQiwugs  
} UaB @  
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} -#HA"7XOE  
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z  
/* t?'!$6  
**SiteInfoBean.java ~S7D>D3S  
*/ vG"=h%  
package NetFox; uD@#
 
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public class SiteInfoBean { Kiu_JzD  
9uA>N  
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private String sSiteURL; //Site's URL u2?|Ue@[  
private String sFilePath; //Saved File's Path 0p!>JQ]m  
private String sFileName; //Saved File's Name 20nP/e  
private int nSplitter; //Count of Splited Downloading File < RH UH)I  

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public SiteInfoBean() ,^. 88<  
{//nSplitter的缺省值为5 S_IUV)  
//default value of nSplitter is 5 TmV,&['mg  
this("","","",5); 4QIX19{"  
} G%W8S \  
/Y7<5!cS  
-K3^BZHI  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^>hWy D  
{ lUvpszH=  
sSiteURL= sURL; )j0TeE1R  
sFilePath = sPath; In<n&ib  
sFileName = sName; m~-K[+ya`D  
this.nSplitter = nSpiltter; m1Mt#@,$  
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} S9~+c  
&b%zQ4%d-`  
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public String getSSiteURL() < F.hZGss7  
{ 3GhRWB-U  
return sSiteURL; !~rY1T~  
} NP/Gn6fr  
f m)pulz  
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public void setSSiteURL(String value) A"G 1^8wvX  
{ ^Uf]Q$uCjE  
sSiteURL = value; ~ijVmWNk  
}
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public String getSFilePath() [k;\SXDZo  
{ w"c
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return sFilePath; IV\'e}  
} %~2YE  
g|vNhq0|i  
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public void setSFilePath(String value) |6K+E6H  
{ ZOeQ+j)|I  
sFilePath = value; 65#'\+  
} 1]@}|  
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public String getSFileName() {^7Hgg  
{ 5BlR1
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return sFileName; ?7.7`1m!v  
} eOs)_?}  
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3 I@}my1  
public void setSFileName(String value) O06"bi5Y  
{ ,P70J
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sFileName = value; jw^<IMAG\8  
} Pa V@aM~3  
06c>$1-?  
OHb[qX\  
public int getNSplitter() pgQV/6  
{ 4GY[7^  
return nSplitter; Rld!,t  
} y)W@{@{kl  
%'s>QF]'  
D*gFV{Ws  
public void setNSplitter(int nCount) oPXkYW  
{ o:3dfO%nuM  
nSplitter = nCount; iB%gPoDCL@  
} w~"KA6^  
} Kgi<UkFP  
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/* ZaV8qAsP  
**Utility.java ['B?i1 .  
*/ &:dH,  
package NetFox; Q;43[1&3w  
gy 3i+J  
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public class Utility { 2\jPv`Ia  
L
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public Utility() b\$}>O  
{ Rv$[)`&T  
&U5{Hm9Ynr  
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}
O4cr*MCb5  
d4>Z8FF|1B  
//线程睡眠 Ay5i+)MD  
public static void sleep(int nSecond) :y%/u%L  
{ *n 6s.$p)%  
try{ $c:ynjL|P-  
Thread.sleep(nSecond); Vzdh8)Mu\  
} #Ssx!+q?  
catch(Exception e) mpuq 9)6  
{ YaKeq5%y  
e.printStackTrace (); TgmnG/Z  
} .!$*:4ok  
} s;S?;(QI  
XWS%zL
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//日志 j/r]wd"aUS  
public static void log(String sMsg) r? NznNVU  
{ =|3
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System.err.println(sMsg); T92UeG  
} GqaDL3Niqs  
7=TF.TW)  
v/68*,z[  
public static void log(int sMsg) j53*E )d  
{ h_:C+)13`x  
System.err.println(sMsg); vq^f}id  
} +eyc`J  
} s:/8[(A  
`\gnl'  
E*V`":efS  
/* s.N7qO^:E  
**TestMethod.java K1r#8Q!t  
*/ P"y`A}Bx  
package NetFox; / ';0H_  
juka0/  
pQ=>.JU  
public class TestMethod { Y;@>b{s  
1zm ulj%&  
j9?}j#@  
public TestMethod() x(etb<!jd  
{ ///xx/weblogic60b2_win.exe :PIF07$xl  
try{ :km61  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Oiz ,w7LRh  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);  FT#8L  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ,2j&ko1  
fileFetch.start(); ?Z Rs\+{vG  
} 7 %Oa;]|  
catch(Exception e){e.printStackTrace ();} \r /ya<5  
b J=Jg~&  
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} ,SynnE68  
-8
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public static void main(String[] args) 
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{ q|o}+Vr  
new TestMethod(); /y _O4  
} %{AO+u2i  
} 01r 8$+  
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