http断点续传简单实现（java)

/* 'e>'JZR  
**SiteFileFetch.java |Eu#mN  
*/ $v8T%'p+  
package NetFox; 3]NKAPY  
import java.io.*; 1)e[F#|  
import java.net.*; lq1223  
V1i^#;  
Dir# [j  
public class SiteFileFetch extends Thread { t&yuo E  
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SiteInfoBean siteInfoBean = null; //文件信息Bean i'ZnU55=  
long[] nStartPos; //开始位置 u9 *ic~Nh  
long[] nEndPos; //结束位置 =%77~q-HL  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 JBV 06T_4o  
long nFileLength; //文件长度 < A`srmS?  
boolean bFirst = true; //是否第一次取文件 _0&U'/cs  
boolean bStop = false; //停止标志 -hK^*vJ  
File tmpFile; //文件下载的临时信息 5n::]Q%=D  
DataOutputStream output; //输出到文件的输出流 G{+zKs}~  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Kk% IN9  
public SiteFileFetch(SiteInfoBean bean) throws IOException us#ji i.<  
{ m9'bDyyK  
siteInfoBean = bean; vN6)Szim  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); wLq#,X>%B  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); +nYF9z2  
if(tmpFile.exists ()) \  6Y%z  
{ }y|_v^  
bFirst = false; ![[:Z  
read_nPos(); Fe2iG-ec  
} 0sq?>$~Kc*  
else Qoz4(~I
 
{ o3'Za'N.  
nStartPos = new long[bean.getNSplitter()]; 4f213h  
nEndPos = new long[bean.getNSplitter()]; H/0b3I^  
} BI>r'  
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} oJc v
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public void run() tv9 R$-cJ  
{ ;3=RM\  
//获得文件长度 ()_^:WQO?  
//分割文件 O2~Q(q'   
//实例FileSplitterFetch bL%-9BG  
//启动FileSplitterFetch线程 M r~IVmtf  
//等待子线程返回 &7w*=f8I  
try{ r#mH[|@W~  
if(bFirst) K &G  
{ #!jwn^yq  
nFileLength = getFileSize(); pQCW6X  
if(nFileLength == -1) UotLJa  
{ 69Q#
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System.err.println("File Length is not known!"); W>$mU&ew[  
} +qa^K%K  
else if(nFileLength == -2) `9DW}  
{ cw;TIx_q  
System.err.println("File is not access!"); DPWnvd  
} g0s*4E  
else E`q)vk   
{ fTI~wF8!  
for(int i=0;i<nStartPos.length;i++) &*qAB)**  
{ 'Y5l3xQk  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); nsXyReWka  
} n?NUnF
A  
for(int i=0;i<nEndPos.length-1;i++) P
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{ k|rbh.Q  
nEndPos = nStartPos[i+1]; U5;Y o+z  
} 5Kkp1K$M  
nEndPos[nEndPos.length-1] = nFileLength; qc/)l~]?g{  
} 'DB'lP  
} RAoY`AWI  
<OGXKv@  
XNkZ^3mq  
//启动子线程 m>^
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $*+`;PG-  
for(int i=0;i<nStartPos.length;i++) ?fvK<0S`  
{ (+9^)No  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )#Id=c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Uclta  
nStartPos,nEndPos,i); 'q{d? K  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _^NL{R/  
fileSplitterFetch.start(); `6Yk-5  
} q[~+Z
m  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), cx+%lco!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); TxmKmZ u  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", aB~=WWLR\  
nEndPos = " + nFileLength); }\.Z{h:t ?  
// fileSplitterFetch[nPos.length-1].start(); pLpWc~#  
a_Z[@W  
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//等待子线程结束 4nD U-P#f  
//int count = 0; CQET  
//是否结束while循环 9y*pn|A[F  
boolean breakWhile = false; F t;[>o  
9
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while(!bStop) <w0$0ku  
{ =\x(Rs3  
write_nPos(); l\t<_p/I)^  
Utility.sleep(500); dQPW9~g8Hg  
breakWhile = true; HAGpM\Qa  
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U"  
for(int i=0;i<nStartPos.length;i++) Kw&t\},8@  
{ { VFr8F0*H  
if(!fileSplitterFetch.bDownOver) \']_y\  
{ -hP>;~*4  
breakWhile = false; l'#a2Pl  
break; ]|K@0,  
} <):= mr7  
} ; Ne|H$N  
if(breakWhile) j%Z%_{6Ds*  
break; '>dx~v %  
m 3"|$0C~  
??? ;H  
//count++; Yi#U~ h  
//if(count>4) FSkz[D_}  
// siteStop(); s)V<dm;T  
} G>j4b}e
 
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System.err.println("文件下载结束！"); ,&rHBNS  
} 3W"l}.&ZJ"  
catch(Exception e){e.printStackTrace ();} =LojRY  
} nrRP1`!]T  
;Km74!.e7  
= GZ,P (
  
//获得文件长度 s92SN F}g  
public long getFileSize() 0tp3mYd  
{ $g]'$PB  
int nFileLength = -1; (b;*8  
try{ "1>48Z-UC  
URL url = new URL(siteInfoBean.getSSiteURL()); hd_<J]C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^n<o,K4\}  
httpConnection.setRequestProperty("User-Agent","NetFox");  |E9iG  
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int responseCode=httpConnection.getResponseCode(); pJ3Yjm[l  
if(responseCode>=400) 9*j$U$:'  
{ GGkU$qp2~  
processErrorCode(responseCode); '(yjq<  
return -2; //-2 represent access is error 05/'qf7P,U  
} QX|y};7\e  
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String sHeader; NKE,}^C  
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for(int i=1;;i++) RP~ hi%A  
{ Eh/Z4pzT  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); eaCh;IpIf  
//Utility.log(in.readLine()); @_C?M5v  
sHeader=httpConnection.getHeaderFieldKey(i); *MZa|Xy  
if(sHeader!=null) ct
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{ xjg(}w  
if(sHeader.equals("Content-Length")) "P@oO,.  
{ hSF4-Vvb  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _!Ir|j.A  
break; h!q_''*;  
} $ {5|{`  
} <t"|wYAa_  
else OCN@P+L3q  
break; wJu,N(U  
} DNy 6Kw  
} 8AuOe7D9A  
catch(IOException e){e.printStackTrace ();} 
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catch(Exception e){e.printStackTrace ();} TjLW<D(i>  
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Utility.log(nFileLength); acdF5ch@  
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return nFileLength; g]E>e v{`  
} CH+mzy  
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K *xca(6  
//保存下载信息（文件指针位置） ;{f4E)t 7  
private void write_nPos() k*uLjU  
{ 6Dz N.fz  
try{ \S[I:fw#&  
output = new DataOutputStream(new FileOutputStream(tmpFile)); P&}J(;Lbl  
output.writeInt(nStartPos.length); `T(T]^C98  
for(int i=0;i<nStartPos.length;i++) ?Oyps7hXx  
{ vG'I|OWg  
// output.writeLong(nPos); +X|^ ~)tMJ  
output.writeLong(fileSplitterFetch.nStartPos);  "DsL$D2e  
output.writeLong(fileSplitterFetch.nEndPos); w-wap  
} /7jb&f   
output.close(); 'jj|bN  
} xmNs<mz  
catch(IOException e){e.printStackTrace ();} e]q(fPK  
catch(Exception e){e.printStackTrace ();} 9HBRWh6  
} WI}cXXUKm0  
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$, @,(M`i}  
//读取保存的下载信息（文件指针位置） zyPc<\HoK  
private void read_nPos() {?hpW+1,#  
{ 1X
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try{ ~1.B fOR8  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =--oH'P=M  
int nCount = input.readInt(); x#c%+  
nStartPos = new long[nCount]; "1|\V.>>;  
nEndPos = new long[nCount]; x_$`#m{hL5  
for(int i=0;i<nStartPos.length;i++) 1Zt>andBF  
{ lNba[
;_  
nStartPos = input.readLong(); bK#S
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nEndPos = input.readLong(); $ n"*scyI  
} 3+oGR5gIN  
input.close(); \k>1q/T0V  
} AtYqD<hl:  
catch(IOException e){e.printStackTrace ();} .-4]FGg3  
catch(Exception e){e.printStackTrace ();} SBh"^q  
} L5 Q^cY]p  
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GiS:Nq`$(  
private void processErrorCode(int nErrorCode) C q)Cwc[H  
{ G;Py%8  
System.err.println("Error Code : " + nErrorCode); ~>B`T%=H  
} r}i}4
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=:;K nS  
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//停止文件下载 0AD8X+M{P  
public void siteStop() ,jq:%Y[KZ  
{ gi #dSd1\&  
bStop = true; SI, t:=D  
for(int i=0;i<nStartPos.length;i++) rBUWzpE"  
fileSplitterFetch.splitterStop(); kcG_ n  
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} UAe8Ct=YJ  
}
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//负责部分文件的抓取 e6gLYhf&  
**FileSplitterFetch.java j06qr\Es  
*/ vo>i36  
package NetFox; XJe}^k  
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import java.io.*; 9:,ZG4s  
import java.net.*; mnL+@mm  
nZ %%{#T7  
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public class FileSplitterFetch extends Thread { bYBEh n  
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String sURL; //File URL |Pi! UZB  
long nStartPos; //File Snippet Start Position xO&qo8*  
long nEndPos; //File Snippet End Position IxaF*4JG  
int nThreadID; //Thread's ID u~7fK  
boolean bDownOver = false; //Downing is over Z -fiJ75  
boolean bStop = false; //Stop identical (\UpJlW  
FileAccessI fileAccessI = null; //File Access interface
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lc\{47LwZ  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException qPBOt;N  
{ s;cGf+  
this.sURL = sURL; K5^`,}Q^  
this.nStartPos = nStart; Zm*qV!  
this.nEndPos = nEnd; ,ygUy]  
nThreadID = id; "h-ZwL  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _p^$.\k"  
} pp@O6  
otX/sg.B*  
|u]IOw&1  
public void run() xVk5%  
{ Ey=ymf.}  
while(nStartPos < nEndPos && !bStop) <$??Z;6  
{ mDx=n.lIz  
]=ADX}  
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try{ .$fSWlM;  
URL url = new URL(sURL); X0Wx\xDg[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0Wj,=9q  
httpConnection.setRequestProperty("User-Agent","NetFox"); =Cd{bj.8  
String sProperty = "bytes="+nStartPos+"-"; P$Q,t2$A  
httpConnection.setRequestProperty("RANGE",sProperty); <nTZs`$LwL  
Utility.log(sProperty); zx5#eMD  
|DYgc$2pN  
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InputStream input = httpConnection.getInputStream(); vi28u xc  
//logResponseHead(httpConnection); +)LCYDRV7  
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byte[] b = new byte[1024];
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int nRead; &\%\"Zh  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ""A6n{4  
{ %JgdLn
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nStartPos += fileAccessI.write(b,0,nRead); Z~F*$jn  
//if(nThreadID == 1) H:S<O%f  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ] n\]ao  
} `hdN 6PgK  
}?o4MiLB  
>#)%/Ti}DU  
Utility.log("Thread " + nThreadID + " is over!"); vVP.9(  
bDownOver = true; yi:}UlO  
//nPos = fileAccessI.write (b,0,nRead); J/IRCjQ}  
} 8L+A&^qx  
catch(Exception e){e.printStackTrace ();} y^z c@f  
} QQHQ3\  
} NcBz("  
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zf&:@P{  
//打印回应的头信息 $6(a6!  
public void logResponseHead(HttpURLConnection con) CF 3V)3}  
{ zU0SlRFu  
for(int i=1;;i++) H32o7]lT  
{ 9c
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String header=con.getHeaderFieldKey(i); \t5_V)P  
if(header!=null) \E[6wB>uN%  
//responseHeaders.put(header,httpConnection.getHeaderField(header));
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Utility.log(header+" : "+con.getHeaderField(header)); \B^NdG5Y  
else M4D  @G  
break; _a f $0!  
} cUr!U\X[  
} na|sKE;{  
?4oP=.  
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()  
public void splitterStop() 7377g'jL  
{ 8+J>jZ  
bStop = true; r6kJV4I=re  
} J.'%=q(Sb  
ANNVE},  

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} q#@r*hl  
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=H3tkMoi2  
/* #4JLWg  
**FileAccess.java z1]nC]2  
*//文件访问(定位，写) t0GJ$])  
package NetFox; 6ypLE@Mk  
import java.io.*; .rITzwgB  
1=7ASS9  
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public class FileAccessI implements Serializable{ N.H<'Q8&  
G|
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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 O@4J=P=w  
RandomAccessFile oSavedFile; PR]b]=  
long nPos; Wa7wV 9  
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public FileAccessI() throws IOException k}p8"'O  
{ $d
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this("",0); -jy0Kl/p  
} T=)qD2?  
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public FileAccessI(String sName,long nPos) throws IOException d#]hqy  
{ :vX%0|  
oSavedFile = new RandomAccessFile(sName,"rw"); Fi67"*gE  
this.nPos = nPos; ZX64kk+
 
oSavedFile.seek(nPos); jw9v&/-  
} _Z!@#y@j  
8#VD u(  
2aX*|DGpw  
public synchronized int write(byte[] b,int nStart,int nLen) f*B
-aj#  
{ w]yVNB  
int n = -1; ,oh;(|=  
try{ ruGeN  
oSavedFile.write(b,nStart,nLen); M;,$
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n = nLen; ]gg(Z!|iQ  
} fggs ;Le  
catch(IOException e) D[#V  
{ Y)DX   
e.printStackTrace (); =u?aP}zc  
} -YAtM-VL  
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return n; B~N3k  
} 5K2K'ZkI  
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} 5.oIyC^Ik  
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i/
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/* y/c3x*l.xL  
**SiteInfoBean.java <JH,B91  
*/ ?KOw~-u  
package NetFox; giX[2`^NG  
(Jw_2pHxr"  
3,Yr%`/5'  
public class SiteInfoBean { Uu5(/vw]  
r+8D|stS  
j&oRj6;Ha+  
private String sSiteURL; //Site's URL #}FUau$  
private String sFilePath; //Saved File's Path [GI~ &  
private String sFileName; //Saved File's Name sqtz^K ROM  
private int nSplitter; //Count of Splited Downloading File U
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public SiteInfoBean() Leb|YX
 
{//nSplitter的缺省值为5 ro\oL  
//default value of nSplitter is 5 L;%w{,Ji  
this("","","",5); @)uV Fw"\  
} twq~.:<o  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7!pKlmQ  
{ ZQ_6I}i")  
sSiteURL= sURL; $VvgzjrH  
sFilePath = sPath; &]#L'D!"  
sFileName = sName; $vfgYl4q  
this.nSplitter = nSpiltter; JRo/ HY+  
v/q-{1  
,;6V=ok  
} xBVOIc[4(  
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public String getSSiteURL() TXmS$q   
{ d@$|zr6  
return sSiteURL; pWGR#x'  
} ]`|$nU}v  
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u  
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public void setSSiteURL(String value) 0_gN]>,9n  
{ p35=CX`T.  
sSiteURL = value; 5'I+%66?h$  
} Giv,%3'  
%7 bd}sJ#  
M`H#Qo5/  
public String getSFilePath() 78uImC*o  
{ q2vD)r  
return sFilePath; 1N8] ~j  
} {,Q)D$i  
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*9EwZwE_K  
public void setSFilePath(String value) Yt]`>C[|D  
{ BB/wL_=:  
sFilePath = value; i D IY|  
} I?3b}#&V9  
F,wB6Cw  
'F/oR/4,  
public String getSFileName() h#
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{ _xaum  
return sFileName; {r&mNbz  
} 6:#o0OeBP  
(@+pz/  
5-|!mSd  
public void setSFileName(String value) @kFZN
6  
{ Yub}AuU`v  
sFileName = value; )A7^LLzG  
} X3:z=X&Zd  
0+FPAqX  
_YF>Y=D-  
public int getNSplitter() L1SKOM$  
{ .KA-=$~J1  
return nSplitter; Trv}YT.  
} :W*yfhLt  
<T}U 3lL^  
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public void setNSplitter(int nCount) s|Mo3_>  
{ |u>(~6  
nSplitter = nCount; x.+T65X~4  
} .5 .(S^u  
} 1&=)Bxg4  
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t{]Ew4Y4%O  
/* U6M~N0)Yr  
**Utility.java Ib#-M;{  
*/ bej(Ds0  
package NetFox; ]->"4,}  
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D;pI!S<#  
public class Utility { <a6pjx>y  
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PlkZ)S7C  
public Utility() loVg{N:  
{ Fc5.?X-  
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O+}py{ st  
} N#T'}>ty  
^jMrM.GY  
//线程睡眠 + `|A/w  
public static void sleep(int nSecond) s:3[#&PQpN  
{ o9eOp3w30  
try{ "JB4Uaa  
Thread.sleep(nSecond); TJ"-cWpO1  
} xnZnbgO+  
catch(Exception e) )zr*Ecz  
{ %10ONe}  
e.printStackTrace (); }nd>SK4  
} H9*k(lnz`  
} >@2<^&K`  
GTdoUSUq  
//日志 %biie  
public static void log(String sMsg) {=Zy;Er  
{ }4|EHhG  
System.err.println(sMsg); ~Gu$EqQ  
} Ek{QNlQ]4  
6gV*G  
#r'MfTr  
public static void log(int sMsg) &b} \).5E  
{ uHgq"e  
System.err.println(sMsg); LiG$M{0  
} &i5@4,p y9  
} vjS`;^9  
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/* eY<<Hld  
**TestMethod.java o$No@~%v  
*/ 1h$?,  
package NetFox; ;'7(gAE
 
4?R979  
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public class TestMethod { xb;{<~`71  
l0Q5q)U1A  
E-z5mX.2  
public TestMethod() =^4Z]d  
{ ///xx/weblogic60b2_win.exe ;st0Ekni)  
try{ r<vMp'u  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ZNQx;51  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5CY%h  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [neuwdN  
fileFetch.start(); E5ce=$o  
} "-Q+!byh  
catch(Exception e){e.printStackTrace ();}
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} ?o" Vkc:  
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public static void main(String[] args) *] ihc u  
{ jWrU'X  
new TestMethod(); X)b$CG  
} P[3i!"O>  
} 25SWIpgG  
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