http断点续传简单实现（java)

/* ?gjM]Ki%:  
**SiteFileFetch.java ~=P&wBnJ  
*/ GiB3.%R`  
package NetFox; n.,\Z(l|0  
import java.io.*; <FmrYwt  
import java.net.*;  N\DEY]  
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public class SiteFileFetch extends Thread { h<i.@&  
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SiteInfoBean siteInfoBean = null; //文件信息Bean DqrS5!C  
long[] nStartPos; //开始位置 di`Ql._M  
long[] nEndPos; //结束位置 13s!gwE)  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >+R`3|o '  
long nFileLength; //文件长度 L~Epd.,Dt  
boolean bFirst = true; //是否第一次取文件 Q4-d2I>0  
boolean bStop = false; //停止标志 qHg\n)R"x!  
File tmpFile; //文件下载的临时信息 T30!'F(*,  
DataOutputStream output; //输出到文件的输出流 URm
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） `DO`c>>K  
public SiteFileFetch(SiteInfoBean bean) throws IOException 0U ?1Yh7 m  
{ mkT
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siteInfoBean = bean; ^-PlTmT  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); (w?@qs!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^~|P[}  
if(tmpFile.exists ()) gSK (BP|  
{ +60zJ4  
bFirst = false; }Gr5TDiV0\  
read_nPos(); Ua\g*Cxh  
} B+eB=KL  
else ZT95g  
{ L{Epkay,{  
nStartPos = new long[bean.getNSplitter()]; |HI=ykfI  
nEndPos = new long[bean.getNSplitter()]; EbuOPa  
} q .nsGbl  
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} ,SuF1&4  
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public void run() <^|8
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{ I,QJ/s
I  
//获得文件长度 fyT:I6*  
//分割文件 *-T3'beg  
//实例FileSplitterFetch 8263  
//启动FileSplitterFetch线程 A!H6$-W|p  
//等待子线程返回 /"tVOv#  
try{ soA>&b!?  
if(bFirst) yPn5l/pDDr  
{ u2y?WcMv  
nFileLength = getFileSize(); J:)Q)MT24:  
if(nFileLength == -1) x "]%q^x  
{ KQaw*T[Q3w  
System.err.println("File Length is not known!"); fyYT#r  
} #*j  
else if(nFileLength == -2) {l.) *#O  
{ 1$?O5.X:  
System.err.println("File is not access!"); xKEHNgen  
} h|mh_T{+  
else *5sr\b4#S  
{ "d/x`Dx  
for(int i=0;i<nStartPos.length;i++) ik_Ll|  
{ 724E(?>J  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Vd4x!Vk  
} [G+M94[A  
for(int i=0;i<nEndPos.length-1;i++) -lRXH7|X  
{ k4'rDJfB  
nEndPos = nStartPos[i+1]; ZGSb&!Ke  
} thOQcOf0$  
nEndPos[nEndPos.length-1] = nFileLength; 0XSZ3dY&+  
} ;n00kel$  
} ko@I]
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//启动子线程 rr'RX  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; w
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for(int i=0;i<nStartPos.length;i++) pq#Hca[  
{ Q?L-6]pg  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fxXZ^#2wX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^;$a_eR  
nStartPos,nEndPos,i); ?W1(
@.  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); E).Nu  
fileSplitterFetch.start(); L,p5:EW8.  
} {tk42}8k  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5'?K(Jdmp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); bT,]=h"0  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", U PGS  
nEndPos = " + nFileLength); acdaDY  
// fileSplitterFetch[nPos.length-1].start(); 4(& W>E  
lE`hC#m  
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//等待子线程结束 ox{)O/aj  
//int count = 0; H5S>|"`e`e  
//是否结束while循环 AVGb;)x#  
boolean breakWhile = false; {1'X
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}=?kf3k  
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while(!bStop) )/HSt%>  
{ &`0y<0z  
write_nPos(); :@KWp{ D7  
Utility.sleep(500); `XB(d@%  
breakWhile = true; VzA~w`$d  
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for(int i=0;i<nStartPos.length;i++) 5.0BaVwi  
{ =PP]L
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if(!fileSplitterFetch.bDownOver) 0yfmQ=,X  
{ ~#h@.yW^JN  
breakWhile = false; 8h=H\v^f  
break; R,x\VX!|  
} =7e~L 3 K  
} 36@)a
5  
if(breakWhile) `S2YBKz,1  
break; m%m/#\J E  
|t1D8){!  
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//count++; \kF}E3~+#  
//if(count>4) eA$9)K1GO  
// siteStop(); 5O#CdN-S  
} 2.p7fu  
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System.err.println("文件下载结束！"); LUna stA^  
} wr~# rfH  
catch(Exception e){e.printStackTrace ();} MIub^ $<C  
} .!\y<9  
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?9mFI(r~  
//获得文件长度 1t+]r:{  
public long getFileSize() oil s;*q  
{ R{NmWj['Mg  
int nFileLength = -1; T|GRkxd,E3  
try{ [(BA:x1  
URL url = new URL(siteInfoBean.getSSiteURL()); Nj1vB;4Nx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F6dm_Oq&  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8iB1a6TlL  
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int responseCode=httpConnection.getResponseCode(); :aV(i.LW  
if(responseCode>=400) O _yJR  
{ 4Smno%jq  
processErrorCode(responseCode); <:-|>R".  
return -2; //-2 represent access is error @2v L'6  
} QKL5! L9`  
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String sHeader; rtS(iD@B"  
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for(int i=1;;i++) ,}2M'DSWa  
{ x|<rt966A  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >:4}OylhM  
//Utility.log(in.readLine()); tQ< ou,  
sHeader=httpConnection.getHeaderFieldKey(i); 
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if(sHeader!=null) IVzJ|  
{ ,@tYD(Z  
if(sHeader.equals("Content-Length")) \m1r(*Ar  
{ A7>0Pn%D3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 3Ew-Ia%A  
break; vRp =L54z  
} V.Dqbv  
} g05:A0X#  
else 'uGn1|Pvy  
break; \9geDX9A  
} [?r`8K2!,  
} T3u%V_  
catch(IOException e){e.printStackTrace ();} )TnxsFC  
catch(Exception e){e.printStackTrace ();} Lfx&DK !  
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Utility.log(nFileLength); M&Sjo' ( .  
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return nFileLength; lsU|xOB  
} MLtfi{;LH  
|!euty ::  
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//保存下载信息（文件指针位置） u3(zixb  
private void write_nPos() F-k3'eyY  
{ P6&@fwJ<  
try{ 51W\%aB  
output = new DataOutputStream(new FileOutputStream(tmpFile)); l3R`3@  
output.writeInt(nStartPos.length); ;g?oU"YM  
for(int i=0;i<nStartPos.length;i++) dX-{75o5P  
{ {1li3K&0s  
// output.writeLong(nPos); " |[w.`  
output.writeLong(fileSplitterFetch.nStartPos); F<Js"z+  
output.writeLong(fileSplitterFetch.nEndPos); cW4:eh  
} 'e_^s+l)a  
output.close(); {"S"V  
} &Ey5 H?U!  
catch(IOException e){e.printStackTrace ();} xgn@1.}G  
catch(Exception e){e.printStackTrace ();} ~J^Gzl  
} !FX0Nx=oi  
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//读取保存的下载信息（文件指针位置） kngkG|du  
private void read_nPos() "toyfZq@  
{ v!27q*;8H  
try{ 7dyGC:YuTL  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #56}RV1  
int nCount = input.readInt(); YHAhF@&  
nStartPos = new long[nCount]; B!0o6)u'  
nEndPos = new long[nCount]; 6+u}'mSj8  
for(int i=0;i<nStartPos.length;i++) D^yZ!}Kl  
{ ZgQ4~s  
nStartPos = input.readLong(); ~B;kFdcVXn  
nEndPos = input.readLong(); <^snS,06  
} j|gQe .,1  
input.close(); r1b{G%;mJ  
} 
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catch(IOException e){e.printStackTrace ();} U\a.'K50F  
catch(Exception e){e.printStackTrace ();} pp@Jndlg  
} DP ,owk  
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private void processErrorCode(int nErrorCode) +EjH9;gx  
{ c,pR+DP  
System.err.println("Error Code : " + nErrorCode); )#n0~7 &  
} @[h)M3DFd  
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/tR@J8pV  
//停止文件下载 mz$)80ly  
public void siteStop() d2`m0U  
{ *@/1]W  
bStop = true; > 2_xRn<P  
for(int i=0;i<nStartPos.length;i++) !)gTS5Rh:  
fileSplitterFetch.splitterStop(); z(b0U6)qQ  
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} X3&-kU  
} 95LZG1]Rb  
//负责部分文件的抓取 3Kuu9<0  
**FileSplitterFetch.java qn) VKx=  
*/ Br^4N9  
package NetFox; dz@L}b*  
g$bbm}6S  
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import java.io.*; aVkgE>  
import java.net.*; 9RA~#S|(T  
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public class FileSplitterFetch extends Thread { 4UwXrEQp  
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String sURL; //File URL I~Y1DP)R  
long nStartPos; //File Snippet Start Position tgmG#b*  
long nEndPos; //File Snippet End Position lh^-L+G:Ok  
int nThreadID; //Thread's ID (ndXz  
boolean bDownOver = false; //Downing is over yF2|w=!  
boolean bStop = false; //Stop identical OXu*wl(z  
FileAccessI fileAccessI = null; //File Access interface N zrHWVD  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException C>l{_J)n  
{ w_zUA'n+  
this.sURL = sURL; o[Ojl.r<  
this.nStartPos = nStart; @c3GJ'"X  
this.nEndPos = nEnd; fKEZlrw  
nThreadID = id; 7G6XK   
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Jv_KZDOdk  
} 2stBW5v3  
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public void run() (4:&tm/;  
{ Y)~Y;;/G  
while(nStartPos < nEndPos && !bStop) hF m_`J&"  
{ 4#<r}j12z  
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try{ ,q9nHZG^  
URL url = new URL(sURL); o>Fc.$ngZ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Vo1,{"k  
httpConnection.setRequestProperty("User-Agent","NetFox"); _FpZc?=  
String sProperty = "bytes="+nStartPos+"-"; )y~FeKh  
httpConnection.setRequestProperty("RANGE",sProperty); g2?kC^=z=  
Utility.log(sProperty); ~!V5Ug_2  
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InputStream input = httpConnection.getInputStream(); QuB`}rfLf  
//logResponseHead(httpConnection); \!-IY  
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byte[] b = new byte[1024]; \\ZR~f!<  
int nRead; 7hV9nu
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Go^a~Sf$  
{ e6G=Bq$  
nStartPos += fileAccessI.write(b,0,nRead); rC!!X  
//if(nThreadID == 1) 8>R 75dw  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qu8!fFQjYL  
} t(~V:+W9  
\@\r`=WgB  
~wejy3|@0  
Utility.log("Thread " + nThreadID + " is over!"); p :v'"A}  
bDownOver = true; ;+-@AYl  
//nPos = fileAccessI.write (b,0,nRead); kdgU1T@y.  
} i}tBB
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catch(Exception e){e.printStackTrace ();} EWb'#+BP  
} E=*82Y=B  
} |_6V+/?"?`  
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f6of8BOg  
//打印回应的头信息 biLN
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public void logResponseHead(HttpURLConnection con) [TW?sW^0  
{ lmGVSdo   
for(int i=1;;i++) c*m7'\  
{ $a@T:zfe  
String header=con.getHeaderFieldKey(i); CI#6r8u  
if(header!=null) ]2_
b_ok  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ^ gMkQYo(#  
Utility.log(header+" : "+con.getHeaderField(header)); 9 HiH6f^5  
else cD%_+@GaU  
break; 7:M`k#oDP  
} *+i1m`6Q  
} VxP cC+  
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+nIjW;RU  
public void splitterStop() ?5IF;vk  
{ >eC>sTPQ{  
bStop = true; hl/) 1sOIR  
} WR.>?IG2E  
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} 0X<U.Sxn  
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-u$U~?|`  
/* 8}?wi[T  
**FileAccess.java Bjp4:;Bb  
*//文件访问(定位，写) j[RY  
package NetFox; KXiStwS  
import java.io.*; RxYC]R^78  
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xxQgX~'x  
public class FileAccessI implements Serializable{ Y6[O s1  
V q[4RAd^P  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @$|8zPs  
RandomAccessFile oSavedFile; ri1;i= W  
long nPos; :\]qB&  
6pdek3pOCt  
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public FileAccessI() throws IOException d6XdN  
{ 4J{W8jX  
this("",0); [$D%]]/,  
} -y'tz,En.  
s}<i[hY>  
ILIv43QKM(  
public FileAccessI(String sName,long nPos) throws IOException 0<)Ep~!  
{ XE$;Z'Qhjm  
oSavedFile = new RandomAccessFile(sName,"rw"); 4d8}g25C  
this.nPos = nPos; &U_T1-UR2  
oSavedFile.seek(nPos); 2@Zw#2|
]  
} 717OzrF}A?  
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{yFMY?6rf  
public synchronized int write(byte[] b,int nStart,int nLen) v@,`(\Ca'  
{ !q1XyQX  
int n = -1; i.0d>G><@  
try{ 4*9BAv  
oSavedFile.write(b,nStart,nLen); G2dPm}sZG  
n = nLen; pD]2.O  
} ujLje:Yc  
catch(IOException e) w:9M6+mM^  
{ OyQ[}w3o|  
e.printStackTrace (); o]B2^Yq;x  
} wAo6:)  
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return n; r2\}_pIj  
} ?L"x>$  
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} I9h{fB  
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/* c~={A  
**SiteInfoBean.java gZ us}U  
*/ 8l<~zIoO  
package NetFox; tm.&k6%  
tILnD1q  
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public class SiteInfoBean { | Pqs)Mb]  
v}<z_i5/C.  
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private String sSiteURL; //Site's URL o\qeX|.70  
private String sFilePath; //Saved File's Path !Pu7%nV.  
private String sFileName; //Saved File's Name 7 6HB@'xY  
private int nSplitter; //Count of Splited Downloading File [6?x 6_M  
X7SSTcA  
(L!u[e0[#  
public SiteInfoBean() y2PxC. -  
{//nSplitter的缺省值为5 _zLEHEZ-  
//default value of nSplitter is 5 W+.?J 60  
this("","","",5); *7qa]i^]  
} n.A*(@noe  
f5R%F~
 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) sA }X)aP  
{ iHWt;]  
sSiteURL= sURL; Lve$H(GHT  
sFilePath = sPath; oTA'=<W?D  
sFileName = sName; ?h8/\~Dw  
this.nSplitter = nSpiltter; &#@"^(} 6  
-./Y  
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} Q
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r<*Y1;7H'  
72y!cK6  
public String getSSiteURL() Lya?b  
{ "?YpF2pD  
return sSiteURL; |h:3BV_  
} 'v@1_HHW\  
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Fh)YNW@  
public void setSSiteURL(String value) Kw>gg  
{ v=H!Y";  
sSiteURL = value; Pv@;)s(-  
} !" : arK  
m>b i$Y  
98WJ"f_ #  
public String getSFilePath() NO#^_N`#\  
{ a[gN+DX%L  
return sFilePath; td+[Na0d  
} EtB56FU\  
,I[A~  
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public void setSFilePath(String value) ix}*whW=U  
{ W/;qMP1"-  
sFilePath = value; J15$P8J  
} yDw^xGws  
;Y16I#?;Kh  
F~O!J@4]  
public String getSFileName() ;:gx;'dm5  
{ Iyvl6  
return sFileName; YCQ+9  
} /t?(IcP5  
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public void setSFileName(String value) FdJC@Y-#uA  
{ uO-R:MC  
sFileName = value; ]0:R^dHE  
} x9CI>l  
K#{E87
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public int getNSplitter() XC{(O:EG  
{ <`m.Vbvm"  
return nSplitter; HM1y$ej  
} gf2w@CVF>=  
=
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9P)
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public void setNSplitter(int nCount) o[ %Q&u  
{ V1;Qt-i  
nSplitter = nCount; (;h]'I@  
} Ic&t_B*i}]  
} BmUzsfD  
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$Y0bjS2J  
/* @;,O V&XYn  
**Utility.java I.e'  
*/ z(orA} [  
package NetFox; qkUr5^1  
@4B2O"z`  
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public class Utility { <p0$Q!^dK=  
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public Utility() (Fgt#H(B  
{ Dfhs@ z  
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} fp![Pbms.  
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//线程睡眠 N[+dX_h  
public static void sleep(int nSecond) }lb.3fqiA  
{ (kuZS4Af  
try{ B=c^ma
  
Thread.sleep(nSecond); \!V6` @0KC  
} 0\~Zg  
catch(Exception e) sTqB%$K}  
{ \%Smp2K  
e.printStackTrace (); [1UqMkXtf  
} sk3;;<H  
} X0$_KPn  
|}|;

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//日志 8say"Qz  
public static void log(String sMsg) ha),N<'  
{ n|
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System.err.println(sMsg); mDmWTq\  
} 5nn*)vK {  
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public static void log(int sMsg) E{ ,O}  
{ _#F'rl6'  
System.err.println(sMsg); .eAC!R  
} -&A[{m<,>  
} DRIv<=Bt  
{LeEnh-  
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/* E)E!  
**TestMethod.java i=a LC*@  
*/ >D;hT*3  
package NetFox; W<L6,  
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dW`D?$(@,  
public class TestMethod { `IoX'|C[h  
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public TestMethod() K5lp-F  
{ ///xx/weblogic60b2_win.exe [s2V-'2  
try{ h<.[U $,  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,lJ6"J\8.  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); h'x~"k1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); TH!8G,(w  
fileFetch.start(); Mg$9'a"[\
 
} ,]mwk~HeF  
catch(Exception e){e.printStackTrace ();} %}!}2s.A  
1znV>PO!  
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} tl5IwrF6;  
:gq@/COo(  
o z{j2%  
public static void main(String[] args) 1}E@lOc  
{ d6EY'*0  
new TestMethod();
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} J\'5CG  
} 7yTe]O  
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