http断点续传简单实现（java)

/* R#(G%66   
**SiteFileFetch.java \ZD[!w7  
*/ XoR>H4xh  
package NetFox; dB;3.<S=  
import java.io.*; Pl+xH%U+?  
import java.net.*; M=y0PCD  
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public class SiteFileFetch extends Thread { f vLC_'M  
:?CQuEv-  
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SiteInfoBean siteInfoBean = null; //文件信息Bean RY=1H  
long[] nStartPos; //开始位置 aMK~1]Cx  
long[] nEndPos; //结束位置 !e3YnlE  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 x*}bo))hb  
long nFileLength; //文件长度 0JY WrPR  
boolean bFirst = true; //是否第一次取文件 :\yc*OtX  
boolean bStop = false; //停止标志 7@~tVxB;  
File tmpFile; //文件下载的临时信息 "tu*YNP\Q  
DataOutputStream output; //输出到文件的输出流 ]Kdet"+  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） S>Z|)I  
public SiteFileFetch(SiteInfoBean bean) throws IOException >UHa  
{ ,EEPh>cXc  
siteInfoBean = bean; /_\W+^
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); R,Oe$J<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); XnU
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if(tmpFile.exists ()) x<B'.3y  
{ *'ZN:5%H  
bFirst = false; x5Zrz<Y$w  
read_nPos(); hu5!ev2  
} A^Cj1:,  
else ohQAA h  
{ v{;7LXy0  
nStartPos = new long[bean.getNSplitter()]; @Doyt{|T  
nEndPos = new long[bean.getNSplitter()]; l1+[  
} 4]&<?"LSK  
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} E9 Y\X  
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public void run() 8SmjZpQ?  
{ \pY^^ l*  
//获得文件长度 BWUq%o,@g  
//分割文件 RiFw?Q+  
//实例FileSplitterFetch K5"sj|d&  
//启动FileSplitterFetch线程 Q9>U1]\  
//等待子线程返回 Y=B3q8l5  
try{ fA^Em)cs2  
if(bFirst) "="O >  
{ n:#TOU1ix<  
nFileLength = getFileSize(); F0dI/+  
if(nFileLength == -1) cFZCf8:zB  
{ %3=J*wj>D  
System.err.println("File Length is not known!"); NHaMo*xQ  
} TD,nI
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else if(nFileLength == -2) J|QiH<  
{ %mI~ =^za  
System.err.println("File is not access!"); ~+n,1]W_  
} BWq/TG=>  
else z&+ zl6  
{ d;G~hVu  
for(int i=0;i<nStartPos.length;i++) m(47s  
{ =Hu0v}i/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); TI9X.E?
 
} z,Lzgh  
for(int i=0;i<nEndPos.length-1;i++) WeT* C  
{ M}F~_S0h  
nEndPos = nStartPos[i+1]; f_6`tq m%  
} Nhf~PO({&  
nEndPos[nEndPos.length-1] = nFileLength; wNQqfqZ  
} LAs7>hM  
} 6rDfQ`f\p  
>bm|%Ou"  
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//启动子线程 )pgrl  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 6m`{Z`c$  
for(int i=0;i<nStartPos.length;i++) 'jaoO9KY K  
{ grcbH  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?&c:q3_-Z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 1;r69e  
nStartPos,nEndPos,i); #MgvG,  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kDsIp=  
fileSplitterFetch.start(); Tj`5L6N;8  
} ;+_8&wbqW  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), JdNF-64ky  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); bI ITPxz  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", _ Jc2&(;  
nEndPos = " + nFileLength); <$Yi]ty  
// fileSplitterFetch[nPos.length-1].start(); Zz"}Cz:bX  
H7&xLYQ2  
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//等待子线程结束 T{Zwm!s  
//int count = 0; IB$7`7  
//是否结束while循环 k3hkk:W  
boolean breakWhile = false; Dz&+PES_k  
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while(!bStop) 8<&EvOk  
{ 2[R$RpA_  
write_nPos(); 3#GqmhqKDk  
Utility.sleep(500); \U
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breakWhile = true; _j ;
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for(int i=0;i<nStartPos.length;i++) *"9<TSU%m  
{ _%pAlo_6  
if(!fileSplitterFetch.bDownOver) 4<v;1   
{ u<Xog$esu  
breakWhile = false; H~fdbR  
break; .5Z_E O  
} /L~m#HxWU  
} hC<14  
if(breakWhile) H{zPft  
break; Q:o7G|C  
^%[F8\}XPJ  
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//count++; W|R-J  
//if(count>4) ,=By$.rr'  
// siteStop(); T@48qg  
} q)I|2~Q c^  
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System.err.println("文件下载结束！"); "yh Pm  
} ~"dhu]^  
catch(Exception e){e.printStackTrace ();}  ?J&)W,~  
} t_c?Wp~tH  
;e{5)@h$  
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//获得文件长度 7_)|I? =0d  
public long getFileSize() ZF{~ih*^u  
{ K0fv( !r{  
int nFileLength = -1; ;VzMU ;j  
try{ +Ui_ O  
URL url = new URL(siteInfoBean.getSSiteURL()); |nxdB&1n
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |4>:M\h  
httpConnection.setRequestProperty("User-Agent","NetFox"); Mq\~`8V  
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int responseCode=httpConnection.getResponseCode();  (_+;R  
if(responseCode>=400) G[yI*/E;  
{ Zf:]Gq1  
processErrorCode(responseCode); >Y&KTSD"  
return -2; //-2 represent access is error vjlGXT`m  
} =*MR(b>  
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String sHeader; Z^_>A)<s<  
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for(int i=1;;i++) km 5E)_]  
{ Ci\? ^  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~j&?/{7I  
//Utility.log(in.readLine()); Pes =aw  
sHeader=httpConnection.getHeaderFieldKey(i); 'mV:@].le  
if(sHeader!=null) q627<  
{ MOH
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if(sHeader.equals("Content-Length")) J r*"V`  
{ A7Y_HIo  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); -!dQ)UEP  
break; (F&YdWe:  
} =,:K)  
} 

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else BKb<2  
break; #PAU'u 3{/  
} (!</%^ZI  
} \E hr@g  
catch(IOException e){e.printStackTrace ();} Yj8&  
catch(Exception e){e.printStackTrace ();} DY3:#X`4  
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Utility.log(nFileLength); e\N0@  
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return nFileLength; z8iENECwj  
} 14l; *  
08r[K(bfb,  
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//保存下载信息（文件指针位置） RVF F6N^  
private void write_nPos() R^tcr)(  
{ fVUKvZ}P*  
try{ L@A9{,9Pl  
output = new DataOutputStream(new FileOutputStream(tmpFile)); s]x2DH+_  
output.writeInt(nStartPos.length); j|4tiv>  
for(int i=0;i<nStartPos.length;i++) |- OHve4A  
{ Xj,j0  
// output.writeLong(nPos); e
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output.writeLong(fileSplitterFetch.nStartPos); (02g#A`  
output.writeLong(fileSplitterFetch.nEndPos); EfSMFPM  
} yN:>!SQ  
output.close(); </ZHa:=7  
} 9dYOH)f  
catch(IOException e){e.printStackTrace ();} \=g!$  
catch(Exception e){e.printStackTrace ();} r@|ZlM@O  
} l<N?'
&  
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//读取保存的下载信息（文件指针位置） /Ynt<S9"  
private void read_nPos() UK:M:9  
{ 0w}{(P;  
try{ eT\p-4b  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); l?/gWD^  
int nCount = input.readInt(); jt%WPkY:  
nStartPos = new long[nCount]; "1%*'B^}bw  
nEndPos = new long[nCount]; cYD1~JX.  
for(int i=0;i<nStartPos.length;i++) `~E<Sf<M  
{ 5f3!NeI  
nStartPos = input.readLong(); *a4 b  
nEndPos = input.readLong(); C->[$HcRa  
} K~JC\a\0  
input.close(); M6x;BjrV  
} (WMLNv  
catch(IOException e){e.printStackTrace ();} g& >mP?  
catch(Exception e){e.printStackTrace ();} Eq7gcDQ  
} G>j"cj  
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private void processErrorCode(int nErrorCode) gTD%4V  
{ STRyW Ml  
System.err.println("Error Code : " + nErrorCode); ZjavD^ky  
} HnK/A0jM  
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//停止文件下载 U]mO7HK  
public void siteStop() #
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{ ]E..43  
bStop = true; ~,+[M-  
for(int i=0;i<nStartPos.length;i++) 0k7"H]J  
fileSplitterFetch.splitterStop(); 4sQ~&@[Q+  
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} T/Ez*iQW  
} 98ayA$  
//负责部分文件的抓取 <H_LFrB$W  
**FileSplitterFetch.java C}bPv+t  
*/ "mG!L$  
package NetFox; y
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import java.io.*; GdL4|xv  
import java.net.*; @Zh8 QI+  
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public class FileSplitterFetch extends Thread { ),)Q{~&`  
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String sURL; //File URL B##C{^5A`  
long nStartPos; //File Snippet Start Position c|3h|  
long nEndPos; //File Snippet End Position FBE @pd  
int nThreadID; //Thread's ID dUUPhk0  
boolean bDownOver = false; //Downing is over }.w#X  
boolean bStop = false; //Stop identical /XbY<pj  
FileAccessI fileAccessI = null; //File Access interface >^sz5d+X  
8o%E&Jg:  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Py}!C@e  
{ aJ% e'F[  
this.sURL = sURL; U3(L.8(sA  
this.nStartPos = nStart; 38OIFT  
this.nEndPos = nEnd; 8UjCX[v  
nThreadID = id; z[_
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 Y!Usce  
} VuP#b'g=|]  
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public void run() 2M!+gk=+  
{ 1"*Nb5s  
while(nStartPos < nEndPos && !bStop) v GulM<YY  
{ Q';\tGy  
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try{ 1e+h9|hGYw  
URL url = new URL(sURL); v3iDh8.__  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xP<H,og&x=  
httpConnection.setRequestProperty("User-Agent","NetFox"); &h_d|8  
String sProperty = "bytes="+nStartPos+"-"; hqwz~Ky}  
httpConnection.setRequestProperty("RANGE",sProperty); UEx(~>  
Utility.log(sProperty); \1eKY^)2  
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InputStream input = httpConnection.getInputStream(); \= )[  
//logResponseHead(httpConnection); (\[jf39e  
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byte[] b = new byte[1024]; h$:&1jVY{  
int nRead; }0(vR_x  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) FE^?U%:u@  
{ D0,o
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nStartPos += fileAccessI.write(b,0,nRead); [rD+8,zVm  
//if(nThreadID == 1) kM6 EZ`mj  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @k#z&@b  
} H>@JfYZ0  
l7=$4As/hI  
:7 s#5b  
Utility.log("Thread " + nThreadID + " is over!"); * wQZ'  
bDownOver = true; \&l*e  
//nPos = fileAccessI.write (b,0,nRead); h|$zHm  
} & y 2GQJE  
catch(Exception e){e.printStackTrace ();} }lrfO_  
} noB}p4  
} K!$\REs  
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//打印回应的头信息 k~W;TCJs
  
public void logResponseHead(HttpURLConnection con)
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{ !X#3
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for(int i=1;;i++) EeF n{_  
{ PN)TX~}  
String header=con.getHeaderFieldKey(i); ~Krg8s!F&  
if(header!=null) WZDokSR  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Z_hBd['!  
Utility.log(header+" : "+con.getHeaderField(header)); A~%g"  
else :\ON+LQr  
break; 8B% O%*5`  
} ^.><t+tM  
} `Q!FMv6Y^  
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public void splitterStop() d/-0B<ts  
{ X/?h!
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bStop = true; rE' %MiIK  
} 6:7:NIl:  
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} 1v8:,!C  
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/* /Va&k4  
**FileAccess.java SgQmYaa&  
*//文件访问(定位，写) LI5cUCl  
package NetFox; ;74DT  
import java.io.*; d$G%F$BTs  
/:c,v-  
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public class FileAccessI implements Serializable{ !WVabdt  
MHzsxF|  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 B39PDJ]hu  
RandomAccessFile oSavedFile; ^.$r1/U  
long nPos; p~{%f#V  
2 3XAkpzp$  
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public FileAccessI() throws IOException ef1N#z%gt  
{ GE|^ryh  
this("",0); 2%No>w}/2  
} d .l
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public FileAccessI(String sName,long nPos) throws IOException
sn T4X  
{ cDh4@V  
oSavedFile = new RandomAccessFile(sName,"rw"); 5)
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this.nPos = nPos; H1c|b!C  
oSavedFile.seek(nPos); aDJjVD  
} WFc[F`b  
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public synchronized int write(byte[] b,int nStart,int nLen) 9p0HFri[  
{ bD^ob.c.A  
int n = -1; K=^_Ndz  
try{ i?s&\3--Y  
oSavedFile.write(b,nStart,nLen); 07WIa@Q  
n = nLen; sNan"  
} sN \}Q#:8  
catch(IOException e) nQ(:7PFa'  
{ x_^OS"h-
 
e.printStackTrace (); 0 6v5/Xf  
} 68G] a N3  
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return n; MxvxY,~{0  
} +sq,!6#G  
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} Fl|&eO,e  
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/* 4lo}-@j  
**SiteInfoBean.java -,CndRKx  
*/ {]^%?]e  
package NetFox; sT T455h)  
,i((;/O6  
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public class SiteInfoBean { lNp:2P  
.6-o?=5  
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private String sSiteURL; //Site's URL B qi
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private String sFilePath; //Saved File's Path Ta5iY }  
private String sFileName; //Saved File's Name -t
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private int nSplitter; //Count of Splited Downloading File )( jNd&H  
l4.@YYzbp.  
0JWD] "  
public SiteInfoBean() YyBq+6nq5  
{//nSplitter的缺省值为5 f(ec/0W  
//default value of nSplitter is 5 F$.s6Hh.  
this("","","",5); ENF@6]  
} 2o7C2)YT$  
U=?"j-wN  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {qdhp_~^l  
{ 4!RI2?4V  
sSiteURL= sURL; _A0avMD}  
sFilePath = sPath; c!FjHlAnP  
sFileName = sName; J_br%AG<p  
this.nSplitter = nSpiltter; dM;WG;8e  
1+ARV&bc  
Dve5m=  
} I6Q_A  
745V!#3!M  
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public String getSSiteURL() 03jBN2[!  
{ / {bK*A!  
return sSiteURL; Z8_gI[
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} ee?Mo`  
rnr8t]  
Tk=3"y+u[  
public void setSSiteURL(String value) >$9yQ9&|  
{ B{i;+[ase  
sSiteURL = value; uWT&`m_(2  
} 49kia!FR  
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kEDZqUD  
public String getSFilePath() L|'ME| '  
{ 9&FV=}MO  
return sFilePath; ,TA[el%#  
} Kt7x'5  
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public void setSFilePath(String value) r:Tb{cA  
{ oD2;Tdk  
sFilePath = value; \} Szb2  
} 85~h+Q;  
zt%Fvn4/pF  
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public String getSFileName() UR=s{nFd  
{ 'GoeVq  
return sFileName; *N+aZV}`Z  
} 'a[|}nJ3  
c324@o^V  
4}FfHgpQ  
public void setSFileName(String value) ]>i0;RME  
{ /Day5\Q#  
sFileName = value; {j@)sDMX  
} ?b$zuJ]  
BC[d={_-  
pU'sADC  
public int getNSplitter() ^( VB5p  
{ ^$ bhmJYT  
return nSplitter; 9\0 K%LL  
} ;z=C]kI6M  
\Y 4Z Q"0Q  
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public void setNSplitter(int nCount) ]V("^.~$+C  
{ RN|..zml  
nSplitter = nCount; VMXXBa&  
} pa73`Ca]  
} x)5v8kgf  
3]'z8i({7Y  
/RmCMT  
/* {G&g+9c&  
**Utility.java ]YzAcB.R  
*/ ?d)|vX3Uf  
package NetFox; !r <|F  
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Zi)8KO[/0  
public class Utility { P9^h>sV  
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C^tC} n1D(  
public Utility() g_X7@Dt  
{ eP?|U.on  
:wAB"TCt0  
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} ufPQ~,.  
TZ2f-KI  
//线程睡眠 B6oAW,3  
public static void sleep(int nSecond) OK}"|:hrd  
{ F#wa)XH
 
try{ z+I-3v  
Thread.sleep(nSecond); b1o(CG(}*  
} !Esiq<Yh  
catch(Exception e) xGA0] _  
{ 9U*vnLB  
e.printStackTrace (); ;N|>pSzmL  
} 6iWuBsal  
} vm4oaVi  
W'$~mK\  
//日志 `s$@6r$
 
public static void log(String sMsg) 6u}NI!he  
{ 7:%K-LeaQu  
System.err.println(sMsg); N';lc:Ah~  
} T5;D0tM/  
m`"s$\fah  
KA#-X2U/  
public static void log(int sMsg) Hkt'~L*   
{ 7d5x4^EYE  
System.err.println(sMsg); E>D@#I>  
} Vba}RF[b  
} }D O#{@af  
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jw[`\h}8  
/* dr o42#$Mo  
**TestMethod.java ?
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*/ TW0^wSm  
package NetFox; 8hg(6 XUG  
xWm'E2  
5P!17.W'u  
public class TestMethod { IM/\t!*7  
K~>kruO";  
BKEB,K=K@  
public TestMethod() =Yk$Q\c
 
{ ///xx/weblogic60b2_win.exe W| p?KJk)  
try{ Dr:}k*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); t;'.D @  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _HQa3wj  
SiteFileFetch fileFetch = new SiteFileFetch(bean); KWo)}m*6  
fileFetch.start(); ?`>yl4  
} dp"w=~53  
catch(Exception e){e.printStackTrace ();} Me>'QVr  
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} .y!Hw{cq  
Jd;1dYkH:  
);[`rXH_  
public static void main(String[] args) 0&x)5^lG  
{ 4$"Lf'sH6  
new TestMethod(); PhS"tOGtX  
} dEiX!k$#  
} {65X37W  
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