http断点续传简单实现（java)

/* W"$sN8K>)  
**SiteFileFetch.java /-s-W<S[  
*/ wwUa+6?  
package NetFox; m) QV2n  
import java.io.*; fRh}n ^X  
import java.net.*; cao=O \Y7  
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public class SiteFileFetch extends Thread { v(=?@tF}E  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 7bSj[kuN  
long[] nStartPos; //开始位置 >UNx<=ry  
long[] nEndPos; //结束位置 Opavno%&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 s_o{w"3X  
long nFileLength; //文件长度 ]"ou?ot }  
boolean bFirst = true; //是否第一次取文件 [8jIu&tJf  
boolean bStop = false; //停止标志 _59f.FsVR  
File tmpFile; //文件下载的临时信息 u43W.4H13  
DataOutputStream output; //输出到文件的输出流 sD#*W<  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） :_k5[KT.]9  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~)CGwST[  
{ Ahkq  
siteInfoBean = bean; t03X/%H  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); BD,J4xH;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &8\6%C
 
if(tmpFile.exists ()) $:|?z_@  
{ e1
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bFirst = false; []:&WA9N  
read_nPos(); mRO@ZY;5  
} ;W{2\ Es  
else \&/V p`  
{ "O~7s}  
nStartPos = new long[bean.getNSplitter()]; vN&(__3((  
nEndPos = new long[bean.getNSplitter()]; G4rd<V0[D  
} (}m2}  
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;  
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} NK\0X5##.  
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public void run() 7<(kvE*x  
{ 7\X_%SM%  
//获得文件长度 ?m9=Me  
//分割文件 uL:NWgN  
//实例FileSplitterFetch >"z`))9  
//启动FileSplitterFetch线程 @i#=1)Ze  
//等待子线程返回 B,` `2\B  
try{ yr*~?\  
if(bFirst)
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{ N/1xc1$SB  
nFileLength = getFileSize(); K,+z^{Hvh  
if(nFileLength == -1) 4^9qs%&  
{ e&K7n
@  
System.err.println("File Length is not known!"); JdUI:(  
} 9|NF)~Q}'  
else if(nFileLength == -2) dp2FC  
{ dnM.  
System.err.println("File is not access!"); 7#*`7 K'P!  
} s!]QG  
else $O fZp<M  
{ 3ly]DTbz  
for(int i=0;i<nStartPos.length;i++) HcV,r,>e  
{ M+)ENve  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 'b6qEU#  
} !<F5W<V  
for(int i=0;i<nEndPos.length-1;i++) .3>q3sS  
{ *ozXilO  
nEndPos = nStartPos[i+1]; '#yIcV$  
} 2+K-I  
nEndPos[nEndPos.length-1] = nFileLength; Cd_H<8__  
} %fXgV\xY  
} ,,g: x  
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//启动子线程 B"`86qc  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; q6o}2<T@  
for(int i=0;i<nStartPos.length;i++) 
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{ SPvKq=,
 
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), cet|k!   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $J]NWgXl@  
nStartPos,nEndPos,i); %wGQu;re  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >keYx<1  
fileSplitterFetch.start(); [t*-s1cq  
} @# .a5  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }{[p<pU$C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); aCyn9Y$=  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", D+h`Z]"|  
nEndPos = " + nFileLength); Pp
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// fileSplitterFetch[nPos.length-1].start(); R#ya9GN{  
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//等待子线程结束 g{hbq[>X]  
//int count = 0; D&6.> wt .  
//是否结束while循环 }dEf |6_  
boolean breakWhile = false; iH-(_$f;  
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while(!bStop) Tq%##  
{ ~-A"M_n ?  
write_nPos(); =05jjR1  
Utility.sleep(500); Qqp=  
breakWhile = true; Nu><r  
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for(int i=0;i<nStartPos.length;i++) G%%5lw!y'  
{ c}2"X,  
if(!fileSplitterFetch.bDownOver) )2F%^<gZ#  
{ hM8FN  
breakWhile = false; HZ89x|Hk_  
break; ZRUI';5x  
} Pj7MR/AH  
} ]w!=1(  
if(breakWhile) mvyOwM  
break; sw,p6T[  
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//count++; g7K<"Z {M  
//if(count>4) Jx8DVjy  
// siteStop(); Z}>+!Z  
} )2bbG4:N  
>UV=k :Q  
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System.err.println("文件下载结束！"); _9z+xl  
} %;O# y3,  
catch(Exception e){e.printStackTrace ();} okBaQH2lUl  
} B,A\/%<  
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//获得文件长度 (U*Zz+ R   
public long getFileSize() J*qo3aJjE  
{ / KKA/  
int nFileLength = -1; A$]#f  
try{ Hnbd<?y   
URL url = new URL(siteInfoBean.getSSiteURL()); B(pHo&ox  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U> {CG+X  
httpConnection.setRequestProperty("User-Agent","NetFox"); 31mlnDif  
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int responseCode=httpConnection.getResponseCode(); N||s#  
if(responseCode>=400) [Ib17#74  
{ u6/;=]0   
processErrorCode(responseCode); 0Pg@%>yb~  
return -2; //-2 represent access is error V`LW~P;  
} m8&
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String sHeader; mz^[C7(q'(  
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for(int i=1;;i++) u6P U(f  
{ #s-li b  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 88c<:fK  
//Utility.log(in.readLine()); +za8=`2o  
sHeader=httpConnection.getHeaderFieldKey(i); wH~kTU2br  
if(sHeader!=null) fX jG5Tv  
{ %Th>C2\  
if(sHeader.equals("Content-Length")) ,;M4jc{  
{ ?|:BuHkT  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); kD bhu^~B  
break; 0oEOre3^%  
} gocrjjAHk  
} E*?<KZe"  
else P>9aI/d9  
break; t%530EB3  
} o!4!"O'E  
} EC|
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catch(IOException e){e.printStackTrace ();} 3pmWDG6L  
catch(Exception e){e.printStackTrace ();} 0(_l|PScF  
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Utility.log(nFileLength); &i!vd/*WlD  
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return nFileLength; P,sjo u^  
} +nQw?'9Z  
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//保存下载信息（文件指针位置） 'Wa,OFd\8  
private void write_nPos() b,KcB
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{ jq08=  
try{ =!m}xdTP  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 97)/"i e  
output.writeInt(nStartPos.length); A{B/lX)  
for(int i=0;i<nStartPos.length;i++) GJqE!I,.  
{ v`1,4,;,qs  
// output.writeLong(nPos); MQKfJru7  
output.writeLong(fileSplitterFetch.nStartPos); C;(t/zh  
output.writeLong(fileSplitterFetch.nEndPos); :a:l j  
} $`Ix:g
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output.close(); ~n}k\s~|4  
} ;\MW$/[JCy  
catch(IOException e){e.printStackTrace ();} wW>)(&!F  
catch(Exception e){e.printStackTrace ();} WL{(Ob  
} ?bw4~  
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//读取保存的下载信息（文件指针位置） gl&5l1&  
private void read_nPos()
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{ OxGE
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try{ pKS {6P  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); @* il3h,  
int nCount = input.readInt(); 1wW)tNKIF  
nStartPos = new long[nCount]; -R>}u'EG>  
nEndPos = new long[nCount]; 81*M= ?  
for(int i=0;i<nStartPos.length;i++) &F}"Z(B<wK  
{ }KhjlPhx  
nStartPos = input.readLong(); _bD/D!|  
nEndPos = input.readLong(); M1=_^f=&.  
} M|CrBJv+F  
input.close(); <GWR7rUH  
} QJ4AL3 ^6
 
catch(IOException e){e.printStackTrace ();} jW5iqU"{*  
catch(Exception e){e.printStackTrace ();} q@Kk\m  
} EnscDtf(  
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private void processErrorCode(int nErrorCode) S!j^|!  
{ Vq}r_#!Q  
System.err.println("Error Code : " + nErrorCode); 5gNLO\  
} {;RF  
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//停止文件下载 1)U}i ^  
public void siteStop() ?vu|o'$T,  
{ [,7-w  
bStop = true; O_CT+Ou  
for(int i=0;i<nStartPos.length;i++) GoeIjuELR  
fileSplitterFetch.splitterStop(); xYT}
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} P3$,ca'  
} $r"A@69^RS  
//负责部分文件的抓取 =h\E<dw  
**FileSplitterFetch.java ~L){O*Z  
*/ "A7<XN<  
package NetFox; N*1  
@KJV1t`  
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import java.io.*; uo 4xnzc  
import java.net.*; .Cfp'u%\;  
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public class FileSplitterFetch extends Thread { 7?"9J`*  
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String sURL; //File URL VwC4QK,d;  
long nStartPos; //File Snippet Start Position `"i^'VL,  
long nEndPos; //File Snippet End Position pW`ntE#L  
int nThreadID; //Thread's ID CD*f4I#d  
boolean bDownOver = false; //Downing is over !k4 }v'=  
boolean bStop = false; //Stop identical ,ZsYXW  
FileAccessI fileAccessI = null; //File Access interface h2im sjf  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException }(8D!XgWa  
{ U&tfl/  
this.sURL = sURL; b\<lNE!L  
this.nStartPos = nStart; 7*R{u*/e  
this.nEndPos = nEnd; J r=REa0  
nThreadID = id; 7O;BS}Lv=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $`-SVC  
} k^L#,:\&V  
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public void run() 7-g]A2N  
{ V'Sd[*  
while(nStartPos < nEndPos && !bStop) P2A]qX  
{ !Qj)tS#Az  
* ePDc'   
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try{ xkk@{}J\  
URL url = new URL(sURL); uK+9gTv  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); SaX,^_GY  
httpConnection.setRequestProperty("User-Agent","NetFox"); T%
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String sProperty = "bytes="+nStartPos+"-"; __oY:d(~  
httpConnection.setRequestProperty("RANGE",sProperty); A&X  
Utility.log(sProperty); [qO5~E`;  
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InputStream input = httpConnection.getInputStream(); e _SoM!;  
//logResponseHead(httpConnection); j3sz*:  
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byte[] b = new byte[1024]; DjevX7Q  
int nRead; |IyM"UH  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) MX4 :e>dtd  
{ &V^  
nStartPos += fileAccessI.write(b,0,nRead); 2fHIk57jP  
//if(nThreadID == 1) t(uB66(_F  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); i4{ /  
} (FjsN5  
.&* ({UM  
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Utility.log("Thread " + nThreadID + " is over!"); x`j$9XN5  
bDownOver = true; |)|vG_  
//nPos = fileAccessI.write (b,0,nRead); $w";*">:0  
} ur~Tql  
catch(Exception e){e.printStackTrace ();} W[jW;uk  
} @vQ;>4i.  
} M;S-ESQ  
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//打印回应的头信息 Q9x` Uy  
public void logResponseHead(HttpURLConnection con) eJVOVPg<,  
{ n41\y:CAo  
for(int i=1;;i++) Wj  
{ FzsS~C$wH{  
String header=con.getHeaderFieldKey(i); (A
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if(header!=null) lhIr]'?l  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); nCSd:1DY  
Utility.log(header+" : "+con.getHeaderField(header)); iBPdCp%]`  
else h!t2H6eyF  
break; x9{Sl[2&  
} ~YT>:Np  
} !kHyLEV  
n_!]B_Vd$  
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public void splitterStop() u[6`Jr~  
{ _+R_ms  
bStop = true; ]mJAKycE%  
} @]VvqCk  
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} 3Oig/KZ  
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H?/cG_^y0  
/* (>Q9
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**FileAccess.java E6wST@r  
*//文件访问(定位，写) "`1of8$X7  
package NetFox; ;Cp/2A}Xx  
import java.io.*; "=Fn.r4I  
zf!\wY"`  
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public class FileAccessI implements Serializable{ %Cbc@=k  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 %N_S/V0`  
RandomAccessFile oSavedFile; .5Z@5g`  
long nPos; 5KPPZmO  
|@bNd7=2d  
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public FileAccessI() throws IOException %H 6ZfEO  
{ gJ[q {b  
this("",0); u>i+R"hi"  
} eJ)KE5%n#  
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public FileAccessI(String sName,long nPos) throws IOException z1KC$~{O  
{ OXCml(>{  
oSavedFile = new RandomAccessFile(sName,"rw");
Ai_|)  
this.nPos = nPos; 63dtO{:4  
oSavedFile.seek(nPos); e!x-:F#4j  
} 9oau_Q#  
2] wf`9ZH  
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public synchronized int write(byte[] b,int nStart,int nLen) VEYKrZA  
{ SIBIh-L  
int n = -1; QO`SnN}  
try{ hs#s $})}Z  
oSavedFile.write(b,nStart,nLen); s1b\I6&:J  
n = nLen; r L|BkN  
} aKU8" 5  
catch(IOException e) bFdg'_  
{ wNZS6JF.d  
e.printStackTrace (); WF.$gBH"  
} N*)8L[7_;  
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return n; QR"O)lP  
} UU~;B  
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} $A0]v!P~i-  
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/* d1_*!LW$  
**SiteInfoBean.java 7Z:l;%]K  
*/ q@yabuN@,j  
package NetFox; .xQ'^
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public class SiteInfoBean { [?o vJ  
cx%9UK*c  
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private String sSiteURL; //Site's URL >l*9DaZ  
private String sFilePath; //Saved File's Path JWjp<{Q;1  
private String sFileName; //Saved File's Name v8(u9V%?6  
private int nSplitter; //Count of Splited Downloading File @uD{`@[  
`fh_8%m]*  
exU=!3Ji  
public SiteInfoBean() d'nuk#r  
{//nSplitter的缺省值为5 6? ly.h$  
//default value of nSplitter is 5 5Jd {Ev  
this("","","",5); ^u&Khc~ y  
} | (9FV^_  
\(t>(4s_~  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) j@\/]oL^We  
{ 5!fW&OiY  
sSiteURL= sURL; #u(,#(P'#  
sFilePath = sPath; &pl)E$Y  
sFileName = sName; ;xq
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this.nSplitter = nSpiltter; W' Y
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}
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public String getSSiteURL() *#p}FB2H#  
{ =Q;dYx%I5  
return sSiteURL; UptKN|S&V  
} /W>?p@j+K  
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@ #J2t#  
public void setSSiteURL(String value) Ku6ndc  
{ ,X| >d
 
sSiteURL = value; XR=ebl  
} z xgDaT  
aa]|  
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public String getSFilePath() <qoc)p=__  
{ 1=_?Wg:  
return sFilePath; 'D+njxCk.A  
} |I]G=.*E  
,
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{JQV~rfh`  
public void setSFilePath(String value) % T$!I(L&  
{ , Sf:R4=  
sFilePath = value; Ayw {I#"  
} 4d`f?8vS  
|em_l$oGc  
4\U"e*  
public String getSFileName()
rJ4A9d3:  
{ GOCe&?  
return sFileName; OS~Z@'Eg  
} RXO}mu]Iu  
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public void setSFileName(String value) 1b7Q-elG  
{ {- &wV  
sFileName = value; F{&0(6^p!  
} O8*yho  
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public int getNSplitter() Wsw/ D  
{ gE&83i"  
return nSplitter; p?s[I)e  
} *%]&5  
;|vn;s/  
c=B!\J<1  
public void setNSplitter(int nCount) 78'3&,+si  
{ meD?<g4n~"  
nSplitter = nCount; |dqAT.  
} 4n\O6$&.x  
} t] G hONN  
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/* 7@!ne&8Z?  
**Utility.java # i|pi'Ij  
*/ >s%m\"|oh  
package NetFox; dJ,,yA*  
IDt7KJ@hc  
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public class Utility { u3vw[k  
;0 9~#Wop  
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public Utility() <`=(Ui$fD  
{ jW.IkG[|  
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G4K3qD#+H  
} )cRP6 =  
VL@e
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//线程睡眠 |("zW7g  
public static void sleep(int nSecond)
}FAO.  
{ -W"w  
try{ Cq%1j[  
Thread.sleep(nSecond); oAq<ag\qV  
} ":Ll.=!  
catch(Exception e) ;fKFmY41  
{ /U,;]^  
e.printStackTrace (); 9d >AnTf&H  
} g
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} {$qLMx';  
QR{pph*zn-  
//日志 s% (|z  
public static void log(String sMsg) b#{[Pk,w9  
{ 6nHyd<o  
System.err.println(sMsg); {P $sQv  
} NR0fxh  
A{KF<Omu  
HF]|>1WV[  
public static void log(int sMsg) "midC(rTm  
{ Jhr3[A  
System.err.println(sMsg); GMYfcZ/,K  
} Yuqt=\? #  
} GUdVsZjz(  
w4\g]\  
`@Tl7I\  
/* u
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**TestMethod.java _';oT*#  
*/ M"<B@p]rk:  
package NetFox; je^=gnq  
2<8JY4]!]  
-k"5GUc|  
public class TestMethod { w>Y!5RnO  
+{pS2I}d  
;-!j,V+$h  
public TestMethod() E [b6k&A  
{ ///xx/weblogic60b2_win.exe z~O:w'(g  
try{ 3zuYN-;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `78)|a*R.  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); wDz}32wB  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ;7w4BJcq']  
fileFetch.start(); &5o ln@YL  
} E\dJb}"x %  
catch(Exception e){e.printStackTrace ();} aX{i   
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`c%{M4bF\  
} =E10j.r  
"`&1"*  
!,zRg5Wp4  
public static void main(String[] args) <
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{ i"J`$u  
new TestMethod();
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} vv5 uU8  
} >* >}d%  
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