http断点续传简单实现（java)

/* d:BG#\e]v  
**SiteFileFetch.java JmxH"7hTE  
*/ JMrEFk  
package NetFox; SxOC1+Oy  
import java.io.*; N5Q[nd  
import java.net.*; c3jx+Q  
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public class SiteFileFetch extends Thread { 8K:y
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SiteInfoBean siteInfoBean = null; //文件信息Bean '[AlhBX  
long[] nStartPos; //开始位置 w>pq+og&  
long[] nEndPos; //结束位置 \-h%O jf4  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 XGYbnZ
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long nFileLength; //文件长度 RL!Oi|8  
boolean bFirst = true; //是否第一次取文件 9s\A\$("l  
boolean bStop = false; //停止标志 }>>1<P<8-  
File tmpFile; //文件下载的临时信息 'u*DA|HC  
DataOutputStream output; //输出到文件的输出流 ]V^iN=(_5  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） RRmz"j>  
public SiteFileFetch(SiteInfoBean bean) throws IOException B3We|oe!  
{ rDm~h~u5  
siteInfoBean = bean; 1oR7iD^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Zq+v6fk_Mn  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); X{5vXT\/y  
if(tmpFile.exists ()) S\:P-&dC  
{ ZP@ $Q%up  
bFirst = false; wPQH(~k:  
read_nPos(); cG[l!Z  
} 0)Uce=t`  
else 8&GBV_`I  
{ 4{y)TZ  
nStartPos = new long[bean.getNSplitter()]; \UPjf]&  
nEndPos = new long[bean.getNSplitter()]; e7^mmm  
} ~xkeuU  
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} ZGexdc%  
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public void run() f.D?sHAn  
{ MqW7cjg  
//获得文件长度 TrlZ9?3#D  
//分割文件 a
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//实例FileSplitterFetch ;&9)I8Us  
//启动FileSplitterFetch线程 gH12[Us'`  
//等待子线程返回 /sx@$cvW  
try{ JZ)RGSG i  
if(bFirst) ,]|#[8  
{ j'Gt&\4  
nFileLength = getFileSize(); |,S+@"0#  
if(nFileLength == -1) a!a-b~#cx  
{ T-
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System.err.println("File Length is not known!"); z>LUH  
} /Lfm&;  
else if(nFileLength == -2) 2^r<{0@n  
{ w mn+  
System.err.println("File is not access!"); c/D+|X*  
} {j9{n  
else 9+j0q%
 
{ YN/|$sMD|  
for(int i=0;i<nStartPos.length;i++) s3z$e+A8  
{ ?M8dP%
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); U>YAdrx2a  
} "Lzi+1  
for(int i=0;i<nEndPos.length-1;i++) ^H~h\,;zQ  
{ p*< 0"0  
nEndPos = nStartPos[i+1]; 9Vg?{v!yn  
} ;y,5k?  
nEndPos[nEndPos.length-1] = nFileLength; 3k\#CiB{  
} g2BHHL;`  
} /Gd=n  
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sZjQ3*<-r  
//启动子线程 G? ]
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <`.X$r*  
for(int i=0;i<nStartPos.length;i++) o)h_H;  
{ QX!-B  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m,VOx7%n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), V[RF</2T  
nStartPos,nEndPos,i); {:Orn%Q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ( Z619w  
fileSplitterFetch.start(); Yrb{ByO&  
} C].iCxn  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q8T]\6)m  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 1#C4;3i,  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", b,5~b&<h  
nEndPos = " + nFileLength); (SWYOMo"  
// fileSplitterFetch[nPos.length-1].start(); x6BuF_.  
<NR#Y%}-V  
bfFeBBi  
//等待子线程结束 zZ7;jyD  
//int count = 0; aT{_0m$G10  
//是否结束while循环 v|gw9  
boolean breakWhile = false; r A`V}>Xj  
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while(!bStop) ^|/TC!v]M  
{ Tl%`P_J)-S  
write_nPos(); EMh7z7}Rr  
Utility.sleep(500); ERUz3mjA/  
breakWhile = true; !02`t4Zc-  
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.7Dtm<K#  
for(int i=0;i<nStartPos.length;i++) lsJSYJG&  
{ LzG%Z1`  
if(!fileSplitterFetch.bDownOver) A0/"&Ag]  
{ &TnS4O  
breakWhile = false; 9Z|jxy  
break; rx'RSo#1O  
} !`k1:@NZ  
} - \5v^l  
if(breakWhile) O@tU.5*$5  
break; RM]\+BK  
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2L:_rR#w  
//count++; `[z<4"Os   
//if(count>4) KT_!d*  
// siteStop(); SOs:]U-T3  
} v]'ztFA  
/'Ass(=6  
|v`AA?@{8  
System.err.println("文件下载结束！"); }K7#Q  
} $3W;=Id=+  
catch(Exception e){e.printStackTrace ();} _64A(U  
} Za/-i"U  
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bENdMH";  
//获得文件长度 bZ?v-fn\D,  
public long getFileSize() $I!XSz"/e  
{ _ q(ko/T  
int nFileLength = -1; 61Bwb]\f/|  
try{ }d[ kxo  
URL url = new URL(siteInfoBean.getSSiteURL()); bbtGXfI+SB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 18)'c?^.  
httpConnection.setRequestProperty("User-Agent","NetFox"); +dWDxguE{w  
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int responseCode=httpConnection.getResponseCode(); ++bf#qS<8D  
if(responseCode>=400) v6[!o<@"a  
{ [/,)  
processErrorCode(responseCode); 8{|8G-Mi  
return -2; //-2 represent access is error 0Be<X  
} 0QBiC]9  
6|
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XQ
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String sHeader; 4{}FL  
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for(int i=1;;i++) ,QOG!T4  
{ N/[p <  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #=D) j  
//Utility.log(in.readLine()); :<ka3<0%  
sHeader=httpConnection.getHeaderFieldKey(i); <vnHz?71c  
if(sHeader!=null) 2;
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{ Kc!}`Pm  
if(sHeader.equals("Content-Length")) }wWKFX  
{ ?# Mr  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8/DS:uM  
break; QsGiclU  
} :lX!\(E2  
} H;D>|q  
else heltgRt  
break; )bA;?i  
} gMv.V{vD  
} )}''L{k-  
catch(IOException e){e.printStackTrace ();} ?RX3MUN
  
catch(Exception e){e.printStackTrace ();} kJWn<5%ayg  
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Utility.log(nFileLength); qBU-~"2t  
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return nFileLength; 7@#>bE6  
} 4]rnY~  
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//保存下载信息（文件指针位置） #mlS}~n  
private void write_nPos() Hh%I0#  
{ Jx_cf9{  
try{ _G_Cj{w  
output = new DataOutputStream(new FileOutputStream(tmpFile)); lackB2J9 A  
output.writeInt(nStartPos.length); ?42<J%p  
for(int i=0;i<nStartPos.length;i++) TSA,WP\  
{ *zNYZ#  
// output.writeLong(nPos); +~St !QV%  
output.writeLong(fileSplitterFetch.nStartPos); 2:*w~|6>}5  
output.writeLong(fileSplitterFetch.nEndPos); ?J'Y&  
} a!
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output.close(); v.\*./-
i  
} -Btk 3  
catch(IOException e){e.printStackTrace ();} 3yANv?$a  
catch(Exception e){e.printStackTrace ();} -1Jg?cPzk  
} '#! gh?  
{Z{75}  
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//读取保存的下载信息（文件指针位置） cD@(/$wt  
private void read_nPos() .=U#eHBdAQ  
{ Pnw]Tm}g  
try{ ~"dA~[r L  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 4pe'06:  
int nCount = input.readInt(); RFKtr  
nStartPos = new long[nCount]; 6L:x^bM  
nEndPos = new long[nCount]; J`^ag'  
for(int i=0;i<nStartPos.length;i++) \:R%4w#Jv  
{ $v,dz_O*\  
nStartPos = input.readLong(); yH7F''O7  
nEndPos = input.readLong(); 8][nm
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} X$%'  
input.close(); QU#w%|
  
} d^/3('H6  
catch(IOException e){e.printStackTrace ();} -HQQw$  
catch(Exception e){e.printStackTrace ();} Yi .u"sh]  
} TPVVck-T8  
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private void processErrorCode(int nErrorCode)
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{ AUeu1(  
System.err.println("Error Code : " + nErrorCode); rMXN[,|v  
} 6Vww;1J  
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=5aDM\L$&  
//停止文件下载 soPLA68  
public void siteStop() ?:Mr=]sD  
{ Qg^cf<X{i  
bStop = true; Kfm5i Q  
for(int i=0;i<nStartPos.length;i++) 8'n/?.7cX  
fileSplitterFetch.splitterStop(); NIh:DbE  
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} _AYXc] 4%  
} r$5i Wu  
//负责部分文件的抓取 .#wqXRd  
**FileSplitterFetch.java mt9.x  
*/ Cv }Qwy  
package NetFox; qd+h$
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import java.io.*; og4UhP^UET  
import java.net.*; ?MXejE
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public class FileSplitterFetch extends Thread { @|LBn6q  
=,%CLS,6w  
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String sURL; //File URL cQG +$0(  
long nStartPos; //File Snippet Start Position ?/TSi0R  
long nEndPos; //File Snippet End Position rJFc({ 0  
int nThreadID; //Thread's ID 0$_oT;{8  
boolean bDownOver = false; //Downing is over YiYV>gaf"H  
boolean bStop = false; //Stop identical vK(i9>;7  
FileAccessI fileAccessI = null; //File Access interface 5pU2|B
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException .7zK@6i  
{ CQZgMY1{  
this.sURL = sURL; Mmj;'iYOwF  
this.nStartPos = nStart; &GNxo$CG  
this.nEndPos = nEnd; v4?x.I  
nThreadID = id; Jwj%_<  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 np%\&CVhN  
} aqYa{hXio  
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public void run() 9k9_mjLZ  
{ RZ6xdq}>  
while(nStartPos < nEndPos && !bStop) 6Ztq  
{ )Y]{HQd  
!(qsD+  
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try{ 6UevpDB  
URL url = new URL(sURL); df*5,NV'-*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h\7fp.  
httpConnection.setRequestProperty("User-Agent","NetFox"); cKN$ =gd  
String sProperty = "bytes="+nStartPos+"-"; ex+\nD>t4  
httpConnection.setRequestProperty("RANGE",sProperty); Wqc)Fv70m  
Utility.log(sProperty); o]Ol8I  
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InputStream input = httpConnection.getInputStream(); !icT/5  
//logResponseHead(httpConnection); iZPCNS"  
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byte[] b = new byte[1024]; aaKN^fi&  
int nRead; HQ|MhM/"  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;2@BO-3K  
{ +zu(  
nStartPos += fileAccessI.write(b,0,nRead); Qd=^S^}(  
//if(nThreadID == 1) V?Z.\~
 
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OS4q5;1#  
} qP2ekI:y  

7a#4tqM#  
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Utility.log("Thread " + nThreadID + " is over!"); hdnTXs@z  
bDownOver = true; ET_W-  
//nPos = fileAccessI.write (b,0,nRead); 4Y,R-+f
 
} _2k]3z?  
catch(Exception e){e.printStackTrace ();} 1^_U;O:I  
} I/M_p^  
} 4 SHU  
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//打印回应的头信息 rSxxH]-  
public void logResponseHead(HttpURLConnection con) {g2@6ct  
{ #?*WPq  
for(int i=1;;i++) pAb.c  
{ _9tK[/h  
String header=con.getHeaderFieldKey(i); ebS0qo[oLH  
if(header!=null) IP``O!WP  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); (T>nPbv)  
Utility.log(header+" : "+con.getHeaderField(header)); wj[\B*$?  
else XO-Prs  
break; u$*56y  
} fGw^:
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} B;R.#^@/  
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public void splitterStop() "Vw m  
{ lY~4'8^  
bStop = true; HS{(v;  
} *+TH#EL2  
} X^|$  
%{(x3\ *&  
} hX`hs-*qM  
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/* |}{B1A  
**FileAccess.java `W dD8E  
*//文件访问(定位，写) 5k6mmiaKk  
package NetFox; <'fdkW  
import java.io.*; &;XAuDw4+i  
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public class FileAccessI implements Serializable{ %honO@$  
QCH}-q)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `(
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RandomAccessFile oSavedFile; :C}2
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long nPos; 2<`.#zIds  
fV v.@HL{  
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public FileAccessI() throws IOException -zp0S*iP7  
{ ?OE.O/~l  
this("",0); d"5oD@JG:  
} Y4cYZS47  
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public FileAccessI(String sName,long nPos) throws IOException ,g7.rEA  
{ a-"k/P#  
oSavedFile = new RandomAccessFile(sName,"rw"); "V>R9dO{"!  
this.nPos = nPos; Cw~RJ^a_  
oSavedFile.seek(nPos); cTXri8K_  
} `((Y
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G0`
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#l4)HV  
public synchronized int write(byte[] b,int nStart,int nLen) Kx.X
7R  
{ MZpK~c1`  
int n = -1; !@x+q)2  
try{ FuUD 61JHY  
oSavedFile.write(b,nStart,nLen); 6*qL[m.F[o  
n = nLen; y kW [B  
} :9R=]#uD  
catch(IOException e) HJ2*y|u  
{ 21ppSN>  
e.printStackTrace (); }w/;){gu  
} G [:N0{v5  
 |y h\  
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return n; }R)=S_j  
} i.xXb[M+  
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} l"q1?kaVg  
/erN;Oo%<  
yf?h#G%24  
/* -*~CV:2iq-  
**SiteInfoBean.java N7b1.]<  
*/ OdQT2PA_  
package NetFox; Qd_Y\PzS  
.MVYB\6Q0  
4EXB;[]  
public class SiteInfoBean { rUlS'L;$"  
Cv>o.Bp|  
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private String sSiteURL; //Site's URL 'S<%Xm  
private String sFilePath; //Saved File's Path L>!8YUz7p$  
private String sFileName; //Saved File's Name TDg@Tg0  
private int nSplitter; //Count of Splited Downloading File u>Rb ?`  
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o7TN,([W  
public SiteInfoBean() RQkyCAGx  
{//nSplitter的缺省值为5 $55U+)C<  
//default value of nSplitter is 5 X; 5
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this("","","",5); -UZ@G~K  
} ]&ixhW  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) R7s|`\  
{ F( Ak  
sSiteURL= sURL; 'JZJFE7Z  
sFilePath = sPath; 6AvHavA^Y  
sFileName = sName; R#n%cXc|  
this.nSplitter = nSpiltter; R*zO dxY  
!j1[$% =#  
ygSL  
} R8
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R//$r%a  
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public String getSSiteURL() X 6lH|R  
{ ;' nL:\  
return sSiteURL; >sD4R}\})  
} 1`LXz3uBe  
0G <hn8>  
BPqGJ7@  
public void setSSiteURL(String value) K9[e>  
{ 6yu]GK}es  
sSiteURL = value; "BKeot[""p  
} sVoW=4V8  
 :Pq.,s  
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public String getSFilePath() 8L5!T6+D&  
{ 3ta$L"a  
return sFilePath; mPPk)qy  
} ~=&t0D  
85IMdZ7I  
#.5
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public void setSFilePath(String value) y/? &pKH^  
{ SQWa
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sFilePath = value; J4tcQ  
} >p])it[q&$  
6P`)%zj  
JI|6B  
public String getSFileName() Ogg#jx(4  
{ /%n`V  
return sFileName; ~~F2Ij  
} )9=(|Lp  
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RGD
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public void setSFileName(String value) 0_yP
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{ | A:@&|  
sFileName = value; _7kM]">j  
} 6<Hu8$G|  
/^#G0f*N  
|%D%0TR&Q  
public int getNSplitter() "Vd_CO  
{ 7m9"8   
return nSplitter; O'NW Ebl/  
} &hV Zx  
!OcENV  
,Vd7V}t  
public void setNSplitter(int nCount) ~S; Z\  
{ %*z-PT22  
nSplitter = nCount; mzD^Y<LTd  
} uXQ >WI@eF  
} "DSPPE&[c  
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8 Op.eYe  
/* 59rY[&|  
**Utility.java o%y;(|4t >  
*/ V+Xl9v4O  
package NetFox; I<h=Cj[[  
>O]s&34  
:a3LS|W  
public class Utility { )%Y IGV;&  
:DkAQ-<~  
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public Utility() dl l%4Sd  
{ noNm^hFL  
q]<xMg#nu  
UP2.]B!d  
} */OI*{Q  
%85Icg  
//线程睡眠 W7UtA.2LT  
public static void sleep(int nSecond) L>Jd7;=  
{ r
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try{ u/AT-er;  
Thread.sleep(nSecond); |V`S>m
%N  
} Sl~x$9`  
catch(Exception e) Fa3gJ[ZAqf  
{ 
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e.printStackTrace (); (TSqc5^H  
} ilEi")b=  
} qeaA&(|5  
@?&Wm3x9  
//日志 FWPW/oC  
public static void log(String sMsg) IlLn4Iw  
{ <>4!XPo%J  
System.err.println(sMsg); ;R[&pDx  
} MV+i{]  
3;$bS<>  
PDw{R]V+  
public static void log(int sMsg) BSXdvI1y  
{ +lp{#1q0  
System.err.println(sMsg); 4/wwn6I}G  
}  Iao[Pyk  
} WPY8C3XO  
#*%fu  
17py).\  
/* x3p9GAd#  
**TestMethod.java VEh]p5D  
*/ N&;\PfG  
package NetFox; #q4*]qGHm  
=B5E0x  
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public class TestMethod { C;#"td  
L:U4N*  
^o%_W0_r  
public TestMethod() e)pTC97^L  
{ ///xx/weblogic60b2_win.exe Hc!!tbBQ  
try{ V;*pL1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 3@X7YgILU  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); k\(4sY M  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =g0*MZ;
"  
fileFetch.start(); Oje|bxQ  
} H2\1gNL  
catch(Exception e){e.printStackTrace ();} sX'U|)/pD  
7,_-XV2  
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} E\e]K !  
=jIxI,  
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public static void main(String[] args) wr@GN8e`  
{ b:x7)$(  
new TestMethod(); }|He?[TR  
} ib50LCm  
} 3}M\c)
 
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