http断点续传简单实现（java)

/* 4.@gV/U(|  
**SiteFileFetch.java C/nzlp~
 
*/ _Se~bkw?v  
package NetFox; <cTusC<  
import java.io.*; 'W0?XaEk-  
import java.net.*; ~c8Z9[QW  
]F&<{\:_}  
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public class SiteFileFetch extends Thread { _VIVZ2mU=  
ep]tio_  
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SiteInfoBean siteInfoBean = null; //文件信息Bean q!l[^t|;  
long[] nStartPos; //开始位置 ==d@0`  
long[] nEndPos; //结束位置 z;x1p)(xt  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Vj.5b0/(  
long nFileLength; //文件长度 y~jKytq^@  
boolean bFirst = true; //是否第一次取文件 4BSSJ@z  
boolean bStop = false; //停止标志 nx<q]Juv\  
File tmpFile; //文件下载的临时信息 gB\ a  
DataOutputStream output; //输出到文件的输出流 0>jo+b\D$  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） |Tz/9t  
public SiteFileFetch(SiteInfoBean bean) throws IOException >icK]W   
{ (+g!~MP  
siteInfoBean = bean; +*OY%;dQ7@  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 4qw&G  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); qGS]2KY  
if(tmpFile.exists ()) | ?Js)i  
{ pq;)l(Hi  
bFirst = false; B@wQ[  
read_nPos(); ;D5B$ @W>  
} zw=as9z1-  
else muSQFIvt  
{ 9HI9([Cs  
nStartPos = new long[bean.getNSplitter()]; wA`A+Z2*?  
nEndPos = new long[bean.getNSplitter()]; Dim,HPx]d  
} BS}uv3  
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,
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} M5OH-'  
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public void run() AuZ?~I1  
{ n*\AB=|X  
//获得文件长度 :z=/z!5:j  
//分割文件 4i'2~w{/  
//实例FileSplitterFetch a.F6!?  
//启动FileSplitterFetch线程 /wIev1Z!Y  
//等待子线程返回 )4[{+OJa  
try{ C._I\:G^  
if(bFirst) 6"Tr$E  
{ 64s9Dy@%F  
nFileLength = getFileSize(); Xg#g`m%(M  
if(nFileLength == -1) ~mUP!f  
{ |L{<=NNs:D  
System.err.println("File Length is not known!"); `m5cU*@D  
} r\+AeCyb"p  
else if(nFileLength == -2) l7 D/]&  
{ IXp P.d  
System.err.println("File is not access!"); Vxif0Bx&/d  
} bHcb.;<  
else AR\1w'  
{ fTM^:vkO  
for(int i=0;i<nStartPos.length;i++) LQYT/  
{ }#@P
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); S<+_yB?  
} (JC -4X_  
for(int i=0;i<nEndPos.length-1;i++) dL"$YU9z  
{ n }la
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nEndPos = nStartPos[i+1]; vO" $Xw  
} wxPg*R+t  
nEndPos[nEndPos.length-1] = nFileLength; <_""4  
} 7I4G:-V:^  
} <wTkPErUG  
qv3L@"Ub  
rS9*_-NH  
//启动子线程 _-g:T&#  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; AiiOs?  
for(int i=0;i<nStartPos.length;i++) 'w.:I TJf  
{ avls[Bq  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }vO^%Gd  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), KM(U-<<R  
nStartPos,nEndPos,i); {rOz[E9vm  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f9u["e  
fileSplitterFetch.start(); "z^Ysvw&~  
} NW=j>7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), e*vSGT$KgL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {Z;W|w1t  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \`x'r$CV  
nEndPos = " + nFileLength); cd}TDd(H%  
// fileSplitterFetch[nPos.length-1].start(); V]}/e!XK
\  
#UU}lG  
a(Z" }m  
//等待子线程结束 K@*m6)  
//int count = 0; e,I-u'mLQs  
//是否结束while循环 M:?eK [h  
boolean breakWhile = false; Z<y+D-/  
?MeP<5\A  
K1z"..(2J  
while(!bStop) zE.4e&m%Z?  
{ fx.FHhVu  
write_nPos(); #.}Su+XF  
Utility.sleep(500); l)VMF44  
breakWhile = true; 5n.4>yOY  
D]b5*_CT  
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for(int i=0;i<nStartPos.length;i++) cJ:BEe  
{ =KT7ZSTV  
if(!fileSplitterFetch.bDownOver) r3Z-mJ$:  
{ D'O[0?N"g  
breakWhile = false; z[qM2  
break; w_eu@R:u@  
} CNcH)2Mk  
} zy@ #R;  
if(breakWhile) & A9psc(,&  
break; . 36'=K  
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3SQ 5C'E  
//count++; +cy(}Vp  
//if(count>4) zG
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// siteStop(); biGaP#"0  
} GLc+`,.  
L6$,<}l  
]2zx}D4f  
System.err.println("文件下载结束！"); & PHHacp  
} E_?3<)l)RI  
catch(Exception e){e.printStackTrace ();} 40%p lNPj  
} 
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vR1%&(f{  
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//获得文件长度 jy@}$g{  
public long getFileSize() f$V']dOj1q  
{ g;]2'Rj  
int nFileLength = -1; aDza"Ln  
try{ )Y?Hf2']  
URL url = new URL(siteInfoBean.getSSiteURL()); "@`
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :Np&G4IM>  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ev0V\tl>0  
Xf
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int responseCode=httpConnection.getResponseCode();
tGmyTBgx  
if(responseCode>=400) L/nz95  
{ *
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processErrorCode(responseCode); +< BAJWU  
return -2; //-2 represent access is error _Zf1=&U#/  
} 8Yq6I>@!  
'{( n
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k~=-o>}C  
String sHeader; ci3{k"  
<;9vwSH>  
9lTA/-  
for(int i=1;;i++) 7Oxvq^[  
{ _IpW&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ,5r 2!d  
//Utility.log(in.readLine()); D"1ciO8^I]  
sHeader=httpConnection.getHeaderFieldKey(i);
=t)eT0  
if(sHeader!=null) =Z-.4\3  
{ i-E&Y*\^9H  
if(sHeader.equals("Content-Length")) [U3z*m>e;  
{ sFS_CyN!7  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); zP=J5qOZ8  
break; bk4%lYJ"  
} SKRD{MRsux  
} d G:=tf&1R  
else >b*P
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break; Fd'Ang6"  
} ,rX!V=Z5  
} <Bu*:O  
catch(IOException e){e.printStackTrace ();} 3Q`'C7Pi  
catch(Exception e){e.printStackTrace ();} >Ckb9A  
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5&94VQ$d  
Utility.log(nFileLength); pm)A*][s  
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return nFileLength; KQW  
} c1n? @L  
7CG_UB  
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//保存下载信息（文件指针位置） V<nzTh
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private void write_nPos() ~=c
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{ 9pjk3a  
try{ @RaMO#  
output = new DataOutputStream(new FileOutputStream(tmpFile)); wp*;F#:G  
output.writeInt(nStartPos.length); GB[W'QGiq  
for(int i=0;i<nStartPos.length;i++) 0W=IuPDU  
{ c yN_Sg  
// output.writeLong(nPos); f$WO{J  
output.writeLong(fileSplitterFetch.nStartPos); CtSAo\F  
output.writeLong(fileSplitterFetch.nEndPos); F1Z20)8K  
} e[e2X<&0RT  
output.close(); yobi$mnsy!  
} 2EE#60  
catch(IOException e){e.printStackTrace ();} = )(;  
catch(Exception e){e.printStackTrace ();} L YH9P-5H  
} ]i$CE|~  
J::SFu=  
q(uu;l[  
//读取保存的下载信息（文件指针位置） `C!Pe84(  
private void read_nPos() @69q// #B  
{ *Li;:b"t  
try{ QCtG #/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); T\cdtjk  
int nCount = input.readInt(); B
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nStartPos = new long[nCount]; $6oLiYFX;  
nEndPos = new long[nCount]; R`$Odplh>  
for(int i=0;i<nStartPos.length;i++) HDy[/7"  
{ VNytK_F0P  
nStartPos = input.readLong(); :wn![<`3q  
nEndPos = input.readLong(); e dD(s5  
} TS1k'<c?  
input.close(); &$+y
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} 1y?TyUP  
catch(IOException e){e.printStackTrace ();} Y,&)%Eo<  
catch(Exception e){e.printStackTrace ();} Z3#3xG5pl  
} "HYK~V  
92} ,A`=  
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private void processErrorCode(int nErrorCode) &'|bZms g  
{ Bq$bxuhV  
System.err.println("Error Code : " + nErrorCode); cc^V~-ph  
} t~bjDV^`  
\{~x<<qFd  
+w}5-8mH&>  
//停止文件下载 % mIq,  
public void siteStop() TAGqRYgi  
{ &_-~kU1K^  
bStop = true; 1P[!B[;c  
for(int i=0;i<nStartPos.length;i++) 4s$))x9p  
fileSplitterFetch.splitterStop(); ?^@;8m  
52%.^/  
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} I.( 9{  
} "+HZ~:~f  
//负责部分文件的抓取 K):)bL(B  
**FileSplitterFetch.java 7tt&/k?Q  
*/ e1'_]   
package NetFox; n ~ =]/  
*np%67=jO  
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import java.io.*; @w|~:>/g  
import java.net.*; w\\   
8taaBM`:  
5$O@+W!?@  
public class FileSplitterFetch extends Thread { u37+B  
;xj
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?EtK/6dJZt  
String sURL; //File URL 4lz9z>J.V  
long nStartPos; //File Snippet Start Position duwZe+  
long nEndPos; //File Snippet End Position $%!]tNGS  
int nThreadID; //Thread's ID 61wGIN2,  
boolean bDownOver = false; //Downing is over u/,m2N9cL  
boolean bStop = false; //Stop identical <GR]A|P  
FileAccessI fileAccessI = null; //File Access interface ZB%7Sr0  
w1iQ#.4K_  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 8~
4{e,} ,  
{ 7W 4[1  
this.sURL = sURL; oFY'Ek;d  
this.nStartPos = nStart; 0gnr@9,X  
this.nEndPos = nEnd; ousoG$Pc  
nThreadID = id; EW YpYMkm  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 `VS/Xyp  
} 30B!hj$C  
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public void run() cvAkP2  
{ N b+zP[C  
while(nStartPos < nEndPos && !bStop) 1s1$J2LX  
{ /)v X|qtIY  
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try{ gIT"nG=a4  
URL url = new URL(sURL); |qZ4h
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Aw >DZ2  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'Z;R!@Dm  
String sProperty = "bytes="+nStartPos+"-"; U?.VY@  
httpConnection.setRequestProperty("RANGE",sProperty); '{C=vW  
Utility.log(sProperty); `qUmOFl  
jagsV'o2  
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InputStream input = httpConnection.getInputStream(); m}8c.OJ>K`  
//logResponseHead(httpConnection); Thz&wH`W  
,.DU)Wi?}  
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byte[] b = new byte[1024]; `@eQL[Z9x  
int nRead; l$z-'  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) V<(cW'zA/  
{ M`S >Q2{  
nStartPos += fileAccessI.write(b,0,nRead); NO;+:0n  
//if(nThreadID == 1) B6|=kl2C  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Vbz$dpT  
} *n}{)Ef  
[{'` |  
 X&(1DE  
Utility.log("Thread " + nThreadID + " is over!"); ]BX|G`CCc  
bDownOver = true; I)n%aTfo8  
//nPos = fileAccessI.write (b,0,nRead); !WAbO(l  
} @0+@.&Z  
catch(Exception e){e.printStackTrace ();} f`vB$r>  
} ])vM# f  
} z,$^|'pP  
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i?||R|>;"'  
//打印回应的头信息 5Vf#
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public void logResponseHead(HttpURLConnection con) na>UF
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{ NouT~K`'  
for(int i=1;;i++) Sh=z  
{ n{=vP`V_  
String header=con.getHeaderFieldKey(i); ~#OnA1)  
if(header!=null) <Y<%=`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ".~,(
*  
Utility.log(header+" : "+con.getHeaderField(header)); F d *p3a  
else C+jlIT+  
break; {ge^&l  
} O &;Cca
 
} ,D;d#fJ  
+>Y2luR1  
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public void splitterStop() 7'CdDB6&.  
{ E%2]c?N5  
bStop = true; }-!0d*I  
} -I'#G D>  
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} }cEcoi<v!  
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/* 42~tdD  
**FileAccess.java h b_"E, `F  
*//文件访问(定位，写) /*i[MB
 
package NetFox; =g UOHH  
import java.io.*; RGf&KV/  
k`_sKr]9  
2.qEy6  
public class FileAccessI implements Serializable{ +9<"Y6  
$mgW|TBXCQ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ~5q1zr)E  
RandomAccessFile oSavedFile; yX0nyhq  
long nPos; *%E4,(T  
4hz T4!15  
P XKEqcQR  
public FileAccessI() throws IOException l1l=
52r   
{ jEVDz  
this("",0); of659~EIW  
} m%]1~b}"  
o#fr5>h-w  
j 4!$[h  
public FileAccessI(String sName,long nPos) throws IOException x8 _f/2&  
{ L 4V,y>  
oSavedFile = new RandomAccessFile(sName,"rw"); ose(#n40  
this.nPos = nPos; nm Y_)s  
oSavedFile.seek(nPos); L`NY^  
} aS=-9P;v  
< KGq  
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public synchronized int write(byte[] b,int nStart,int nLen) _wH>h$E  
{ k<Qhw)M8  
int n = -1; 1o`zAJ8|2  
try{ 4A"3C  
oSavedFile.write(b,nStart,nLen); \2)D  
n = nLen; xsu9DzPf&{  
} :y'E
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catch(IOException e) EMQGP<[  
{ \Kr8k`f  
e.printStackTrace (); `,QcOkvbC  
} _t&`
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=g
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return n; l0 =[MXM4  
} }@x!r=O)I  
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} ;`Nh@*_  
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/* mC2K &'[  
**SiteInfoBean.java G?kK:eV  
*/ =' uePM")  
package NetFox; 7-:R{&3Lm:  
l^F ?^kP  
(Zg'])  
public class SiteInfoBean { 50_[n$tqE  
plL|Ubn  
aD]! eP/)  
private String sSiteURL; //Site's URL wg%g(FO  
private String sFilePath; //Saved File's Path &hEn3u  
private String sFileName; //Saved File's Name &S,_Z/BS;  
private int nSplitter; //Count of Splited Downloading File 0vETg'r  
vj
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Z_W
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public SiteInfoBean() `AYq,3V  
{//nSplitter的缺省值为5 }@eIO|  
//default value of nSplitter is 5 Hz\@#  
this("","","",5); m/z,MT74*J  
} w 5 yOSz  
u 3^pQ6Q  
&1(- 8z*  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) XNgcBSD  
{ i.k7qclL`  
sSiteURL= sURL; 8EI9&L>  
sFilePath = sPath; 8~tX>q<@q  
sFileName = sName; U%q-#
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this.nSplitter = nSpiltter; F+"_]  
* xCY^_  
h PL]B_<  
} }R`Rqg-W  
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],_+J*  
public String getSSiteURL() )/?H]o$NU  
{ Aa=:AkrH  
return sSiteURL; h5SJVa  
} q.p.$)  
,jOJ\WXP  
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public void setSSiteURL(String value) %x
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{ v\GVy[Qyv  
sSiteURL = value; ]}dQ~lOE  
} k,[*h-{8  
4qdoF_  
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public String getSFilePath() ;-6-DEL  
{ MjU|XQS:  
return sFilePath; V(_1q  
} B*N1)J\5  
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lDTHK2f  
public void setSFilePath(String value) -QroT`gy  
{ B2e"  
sFilePath = value; ?u|@,tQ[  
} 4qE95THB  
<q8@a0e@  
q pC
I[[  
public String getSFileName() _]-4d_&3(  
{ C,An\lsT  
return sFileName; nq)F$@  
} Xx"<^FS[zC  
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public void setSFileName(String value) < cvh1~>(  
{ 0V4B Q:v  
sFileName = value; n:,mo}?X  
} e"ehH#i  
OvtE)ul@  
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public int getNSplitter() 51SmoFbMz  
{ X*QS/\  
return nSplitter; P(hGkY=(  
} X_]rtG  
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g  
&3BoK/y3  
public void setNSplitter(int nCount) |'q%9#  
{ >#w;67he2  
nSplitter = nCount; ZEAUoC1E1  
} SVZocTt  
} v1TFzcHl<  
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/* dE7S[O  
**Utility.java ^U}k   
*/ x@t?7 o\&  
package NetFox; z3Q&O$5\  
.\n` 4A1z  
+n)n6
}S  
public class Utility { T.4&P#a1  
@1MnJP  
"9wD|wsz  
public Utility() Dwp,d~z  
{ m
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98>GHl'lM  
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} Mfj82rHg  
6qWUo3  
//线程睡眠 zxbfh/=  
public static void sleep(int nSecond) [=
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{ FTf#"'O  
try{ v $I
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Thread.sleep(nSecond); ''y.4dvX  
} s/E|Z1pg3  
catch(Exception e) AcC &Q:g  
{ yD7BZI xW  
e.printStackTrace (); ;-+q*@sa]  
} o4);5~1l  
} 1~5DIU^  
0zaK&]oY0  
//日志 A&Y5z[p  
public static void log(String sMsg) T5(S2^)o  
{ iwotEl0*{  
System.err.println(sMsg); ,`@pi@<"#  
} '<R>cN"  
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aD^$v  
public static void log(int sMsg) n
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{ 3v/B*M VI  
System.err.println(sMsg); OT9]{|7  
} rtV`Q[E  
} K~N$s"Qx  
E TT46%Y  
jJy:/!i  
/* EB~]6.1  
**TestMethod.java S+ kq1R  
*/ )cqD">vs  
package NetFox; F (*B1J2_g  
gcJ!_KZK  
$[ {5+*  
public class TestMethod { [#PE'i4  
szI7I$Qb  
x:|Y)Dn\  
public TestMethod() g.lTNQm$u  
{ ///xx/weblogic60b2_win.exe 3JCo!n0  
try{ ]&cnc8tC  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :xd;=;q5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); . %RM8  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 1Kg0y71"  
fileFetch.start(); f7Gn$E|/r;  
} )@PnpC%H  
catch(Exception e){e.printStackTrace ();} L, JQ\!c  
?'
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} dftBD  
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public static void main(String[] args) ;G[V:.o-  
{ 4,9$udiGY  
new TestMethod(); j[>cv;h ;  
} *{g3ia  
} y0zMK4b  
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