http断点续传简单实现（java)

/* eOlKbJU  
**SiteFileFetch.java Al"3 kRJJ  
*/ P @%.`8  
package NetFox; ,%"xH4d  
import java.io.*; zi]%Zp  
import java.net.*; c$E)P$<j  
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public class SiteFileFetch extends Thread { 0`#(Toe{B  
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SiteInfoBean siteInfoBean = null; //文件信息Bean %B2XznZ:  
long[] nStartPos; //开始位置 yOXO)u1n  
long[] nEndPos; //结束位置 <EX7WA  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 }6zbT-i  
long nFileLength; //文件长度 *b(wVvz  
boolean bFirst = true; //是否第一次取文件 oW}!vf3z  
boolean bStop = false; //停止标志 t={0(  
File tmpFile; //文件下载的临时信息 }U5Y=RYo  
DataOutputStream output; //输出到文件的输出流 :>3=gex@^0  
6.Ie\5-a;  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ;6;H*Y0,|E  
public SiteFileFetch(SiteInfoBean bean) throws IOException Wsz0yHD[`  
{ *MM#Z?mP  
siteInfoBean = bean; >=,uau7  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); F#r#}.B='U  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); X~U >LLr  
if(tmpFile.exists ()) iDb;_?  
{ xp \S2@<  
bFirst = false; u</8w&!  
read_nPos(); I+?hG6NM  
} rs8\)\z  
else B&KL2&Z~Pq  
{ {ShgJ;! Q  
nStartPos = new long[bean.getNSplitter()]; mB55PYA  
nEndPos = new long[bean.getNSplitter()]; 3Kq`<B~%  
} \{|ImCH  
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} sRRI3y@  
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public void run() +c,[ Q  
{ ETw]! br  
//获得文件长度 t%0?N<9YkU  
//分割文件 >9K//co"of  
//实例FileSplitterFetch S'i;xL>  
//启动FileSplitterFetch线程 kToOIx  
//等待子线程返回 bY8
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try{ M?&zY "c  
if(bFirst) Buc_9Kzw<+  
{ 19
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nFileLength = getFileSize(); UPh=+s #Q  
if(nFileLength == -1) 4iX-(ir,  
{ je%M AgW`  
System.err.println("File Length is not known!"); 649 !=  
} 7k8n@39?  
else if(nFileLength == -2) j~av\SCU*  
{ VV3}]GjC  
System.err.println("File is not access!"); QTJu7^O9  
} JJk#,AP  
else a:!uORQby  
{ pa/9
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for(int i=0;i<nStartPos.length;i++) #gZ|T M/h  
{ ~9M!)\~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ;IP~
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} D!3{gV#  
for(int i=0;i<nEndPos.length-1;i++) v548ysE)  
{ 5G*II_j  
nEndPos = nStartPos[i+1]; :hqZPajE  
} V0i9DK|!  
nEndPos[nEndPos.length-1] = nFileLength; G?)vWM`j  
} .Ao0;:;(2-  
} MK$Jj"  
q? z>  
<4X?EYaTq  
//启动子线程 =:7$/T'Qg  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; [?KIN_e#  
for(int i=0;i<nStartPos.length;i++) 'CV^M(o'9  
{ vgG}d8MW37  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;)/
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), J\`^:tcG  
nStartPos,nEndPos,i); EA0iYzV  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fEqC] *s  
fileSplitterFetch.start(); KCqqJ}G  
} )2j:z#'>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bKz{wm%
 
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3VO:+mT  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \HSicV#i  
nEndPos = " + nFileLength); ?Myh7  
// fileSplitterFetch[nPos.length-1].start(); O.\h'3C  
@6MAX"  
!D:k!  
//等待子线程结束 >)Dhi+D  
//int count = 0; o:\XRPB  
//是否结束while循环 @EZ>f5IO+  
boolean breakWhile = false; zG% |0  
rw u3Nb  
3E|;r _; 8  
while(!bStop) A~71i&  
{ ZgYZwc&-  
write_nPos();  rz  
Utility.sleep(500); &?<AwtNN  
breakWhile = true; PZOORjF8A  
~"7J}[i5  
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for(int i=0;i<nStartPos.length;i++) &L3#:jSk  
{ :JV\){P  
if(!fileSplitterFetch.bDownOver) .h8M  
{ CT"Fk'B'  
breakWhile = false; k|j:T[_  
break; OgMI  
} +V
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} w-rOecwFvu  
if(breakWhile) rg)h
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break; #+G`!<7/@f  
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[m#NfA:h,  
//count++; xs1bxJ_R  
//if(count>4) j%xBo:
 
// siteStop(); Bw-s6MS  
} H@W0gK(cS;  
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System.err.println("文件下载结束！"); [x_s/"Md;  
} rm|7 [mK  
catch(Exception e){e.printStackTrace ();} %V_eJC""?  
} mw+j|{[  
h$&rE@N|  
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//获得文件长度 ]
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public long getFileSize() 2Ow<`[7  
{ a<p %hY3  
int nFileLength = -1; +Jq`$+%C  
try{ !;WbOnLP  
URL url = new URL(siteInfoBean.getSSiteURL()); -1mvhR~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); d}% (jJ(I  
httpConnection.setRequestProperty("User-Agent","NetFox"); `o-*Tr  
6\`DlUn'*  
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int responseCode=httpConnection.getResponseCode(); z93nYY$`Y  
if(responseCode>=400) ;&mxqY8`'  
{ 6ZgNHARS  
processErrorCode(responseCode); p#<nK+6.8  
return -2; //-2 represent access is error Q\WXi  
} VM;g+RRq  
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taV|YP$  
String sHeader; F@^N|;_2  
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5"2@NL  
for(int i=1;;i++) =1Sy@MbH3  
{ MBO,\t.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ;tr)=)q&  
//Utility.log(in.readLine()); Rp4FXR jC  
sHeader=httpConnection.getHeaderFieldKey(i); gMay  
if(sHeader!=null) 9:\A7 =  
{ DpNX66O  
if(sHeader.equals("Content-Length"))  2}!R T  
{ iiN?\OO^~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); sL mW\\kA>  
break; bL MkPty  
} L8D
m9}  
} 3N3*`?5c<  
else \E&thp  
break; Zh? V,39  
} .h6Y<
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} wRi~Yb?  
catch(IOException e){e.printStackTrace ();} [oJ& J>U'  
catch(Exception e){e.printStackTrace ();} JU2P%3  
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Utility.log(nFileLength); I1v@\Rb  
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return nFileLength; GZ,j?@  
} )u Qvt-  
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8E-Ip>{>  
//保存下载信息（文件指针位置） c}'Xoc  
private void write_nPos() 8xgc[#  
{ !xH,y  
try{ n4R]+&*  
output = new DataOutputStream(new FileOutputStream(tmpFile)); b<\GI7  
output.writeInt(nStartPos.length); M;
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for(int i=0;i<nStartPos.length;i++) ~QO< B2hS}  
{ .Nk
6  
// output.writeLong(nPos); *V<)p%l.  
output.writeLong(fileSplitterFetch.nStartPos); 3l+|&q[v  
output.writeLong(fileSplitterFetch.nEndPos); 0@w&J9yG  
} =xoBC&u  
output.close();  HFv?s  
} u{pTva  
catch(IOException e){e.printStackTrace ();} YpiRF+G  
catch(Exception e){e.printStackTrace ();} J]\s*,C&  
} flPZlL  
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//读取保存的下载信息（文件指针位置） @21
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private void read_nPos() L*IU0Jy>  
{ %Au T8  
try{ nE^wxtY  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); k=FcPF"  
int nCount = input.readInt(); pBvo M={2!  
nStartPos = new long[nCount]; W*3o|x  
nEndPos = new long[nCount]; DWdLA~'t  
for(int i=0;i<nStartPos.length;i++) JqQ3C}z  
{ a0)vvo=bz  
nStartPos = input.readLong(); }il%AAI9}r  
nEndPos = input.readLong(); cS5w +
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} ^`/V i  
input.close(); (+@faP  
} Lq%[A*`^  
catch(IOException e){e.printStackTrace ();} 65uZLsQ  
catch(Exception e){e.printStackTrace ();} svF*@(-P#  
} EJv!tyJ\[  
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private void processErrorCode(int nErrorCode) Re7{[*Q4  
{ +6uOg,;  
System.err.println("Error Code : " + nErrorCode); }@3$)L%n_u  
} 1RmBtx\<  
p-a]"l+L  
+7`u9j.  
//停止文件下载 _AVy:~/  
public void siteStop()  I8:"h  
{ Qz'O{f  
bStop = true; rffVfw  
for(int i=0;i<nStartPos.length;i++) ws#hhW3qK  
fileSplitterFetch.splitterStop(); O^y$8OKEi,  
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} TeOFAIU  
} #@IQlqJfY7  
//负责部分文件的抓取 K,Lr+  
**FileSplitterFetch.java w6%l8+{R  
*/ OX'/?B((  
package NetFox; 9Y;}JVS  
)kFme=;  
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import java.io.*; Q,ZkeWQ7%  
import java.net.*; 3L%Y"4(mm  
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public class FileSplitterFetch extends Thread { D86K$IT  
]
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String sURL; //File URL n\~"Wim<b  
long nStartPos; //File Snippet Start Position I #Arr#%  
long nEndPos; //File Snippet End Position ag|9$  
int nThreadID; //Thread's ID BF@m)w.v  
boolean bDownOver = false; //Downing is over F^4*|g  
boolean bStop = false; //Stop identical KB$ vQ@N  
FileAccessI fileAccessI = null; //File Access interface ;""-[4C  
= .fc"R|<K  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 5;r({J  
{ A{xSbbDk  
this.sURL = sURL; !.x=r  
this.nStartPos = nStart; O%rS;o  
this.nEndPos = nEnd; :==UDVP  
nThreadID = id; lsTe*Od  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7N&3FER  
} EuhF$L1  
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!&W"f#_Z  
public void run() Yqq$kln  
{ QSlf=VK*y  
while(nStartPos < nEndPos && !bStop) K*hf(w9="%  
{ "a2H8x  
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vq@#Be?@  
try{ %t,1_c0w  
URL url = new URL(sURL); %a%+!wX0x  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I_{9eG1w?  
httpConnection.setRequestProperty("User-Agent","NetFox"); }[YcilU_  
String sProperty = "bytes="+nStartPos+"-"; Cf8R2(-4  
httpConnection.setRequestProperty("RANGE",sProperty); lk5_s@V l  
Utility.log(sProperty); $\=6."R5<  
w+:+r/!g  
#)IdJ]  
InputStream input = httpConnection.getInputStream(); f?oI'5R41  
//logResponseHead(httpConnection); B$iMU?B3  
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byte[] b = new byte[1024]; XmE_F  
int nRead; nJ
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) kr &:;  
{ J\,@Bm|1n{  
nStartPos += fileAccessI.write(b,0,nRead); XF0*d~4  
//if(nThreadID == 1) >QbI)if`1  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mo97GW  
} C 6:pY-  
i1kh@s~8UC  
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Utility.log("Thread " + nThreadID + " is over!"); J{v6DYhi  
bDownOver = true; U/~Zk@3j  
//nPos = fileAccessI.write (b,0,nRead); ^$^Vd@t>a  
} aTsy)=N  
catch(Exception e){e.printStackTrace ();} la6e`  
} NWq [22X |  
} 6Wcn(h8%*  
0.3[=a43  
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//打印回应的头信息 dRarNW  
public void logResponseHead(HttpURLConnection con) `\}zm~  
{ zjhR9  
for(int i=1;;i++) 8I|1Pl  
{ J0{WqA.P  
String header=con.getHeaderFieldKey(i); G/^5P5y%@
 
if(header!=null) 'SXpb?CZ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "1\RdTw  
Utility.log(header+" : "+con.getHeaderField(header)); /-cX(z 7  
else A*?/F:E  
break; u+"hr"}${  
} 8wNU2yH+D  
} b]s%B.h  
e=NQY8?  
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public void splitterStop() ;U5x'}%0]  
{ Ib<5u  
bStop = true;
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} `XRb:d^  
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} VA*79I#_q  
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/* -t706(#k  
**FileAccess.java +BTNm66Z  
*//文件访问(定位，写) )l81R  
package NetFox; 2+hfbFu,1  
import java.io.*; {e!uvz,e  
^Xz`hR   
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public class FileAccessI implements Serializable{ ^5iY/t~Q  
I
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 H;"N|pBy  
RandomAccessFile oSavedFile; #h|,GvmF<b  
long nPos; lQ(BEv"2G[  
-n$rKEC4  
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public FileAccessI() throws IOException Z!BQtICs  
{ kkuQ"^<J  
this("",0); r5$?4t  
} /A`zy  
QK/+*hr;  
#+5mpDh  
public FileAccessI(String sName,long nPos) throws IOException )}g4Rvr  
{ D-\'P31  
oSavedFile = new RandomAccessFile(sName,"rw"); "YJ;-$rb  
this.nPos = nPos; Hi 0df3t  
oSavedFile.seek(nPos); 3qwYicq,  
} @R Yb-d  
q?'gwH37  

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public synchronized int write(byte[] b,int nStart,int nLen) s9Q)6=mE  
{ %BP)m(S7  
int n = -1; ^zs4tCW%  
try{ '%r@D&*vp  
oSavedFile.write(b,nStart,nLen); 8 H"f9S=K  
n = nLen; 0aN}zUf  
} "oGM>@q=B  
catch(IOException e) r:\5/0(  
{ ff+9(P>*  
e.printStackTrace (); =2V;B  
} m"> =QP  
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return n; fbbl92p  
} EG:WE^4  
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 B*~Bm.  
} QcVtv7+*v  
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/* Q)i`.mHfFI  
**SiteInfoBean.java eX),B  
*/ >"My\o  
package NetFox; !/lYq;$R  
o_^d>Klb8  
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public class SiteInfoBean { aG
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1H@rNam&  
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private String sSiteURL; //Site's URL lM]),}   
private String sFilePath; //Saved File's Path #?d#s19s  
private String sFileName; //Saved File's Name '-~/!i+=  
private int nSplitter; //Count of Splited Downloading File ?01""Om   
K@u."e
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~rfjQPbh9x  
public SiteInfoBean() FH5bC6  
{//nSplitter的缺省值为5 UE;)mZ=l|  
//default value of nSplitter is 5 sNpBTG@{l  
this("","","",5); m6ws#%|[  
} '|R@k_nx  
xWZcSIH!  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Br$PL&e~  
{ u! FSXX<  
sSiteURL= sURL; )h!l%7
2  
sFilePath = sPath; Yt<PKs#E  
sFileName = sName; Y>m=cqR  
this.nSplitter = nSpiltter; 0mi[|~x=  
V.[#$ip6:  
'{*>hj5.8  
} P T.jR*  
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public String getSSiteURL() PKs%-Uk  
{ e{+{,g{iu  
return sSiteURL; @BW8`Ky
1  
} =}KbE4D+8  
~F6gF7]z  
|dzF>8< )  
public void setSSiteURL(String value) ~,65/O  
{ 6OW-Dif^AG  
sSiteURL = value;
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} >o=p5#{  
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public String getSFilePath() 3^UsyZS)  
{ P&^7wud-sb  
return sFilePath; e[dRHl  
} aM}"DY-_ h  
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public void setSFilePath(String value) 0qUap*fvC  
{ 1}M.}G2u/  
sFilePath = value; meD (ja  
} m =F@CA~C  
=eLb"7C#0  
OYy !4Fp  
public String getSFileName() c9@jyq_H?  
{ ng*E9Puu[  
return sFileName; A:J{  
} 4N0nU  
<5}du9@  
u@'zvkb@  
public void setSFileName(String value) A+D
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{ X&8,.=kt"  
sFileName = value; `R?W @,@'  
} sB/s17ar  
p>
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public int getNSplitter() GP'Y!cl  
{ :vT%5CQ  
return nSplitter; 3) 0~:  
} D.!7jA#  
~B\:  
HwuPjc#
 
public void setNSplitter(int nCount) F
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{ m3-J0D<  
nSplitter = nCount; _=x_"rzx  
} xB+H7Ya  
} eF1%5;" W  
XOU$3+8q5  
]w_)Spo.  
/* =lD]sk  
**Utility.java @v=q,A8_  
*/ fMaNv6(  
package NetFox; NyLnE  
loe>"_`Cq  
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public class Utility { R  |%  
d vxEXy  
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public Utility() jtY~-@*  
{ VAt9JE;#  
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)&<ExJQ&  
} V,5}hQJ F  
x&vD,|V!  
//线程睡眠 LL [>Uu?Y  
public static void sleep(int nSecond) :/qO*&i,N  
{ NvZ?e  
try{ ;#j82  
Thread.sleep(nSecond); ,+9r/}K]/  
}  gVkI=J  
catch(Exception e) Fo~v.+^?  
{ RkwY3s"  
e.printStackTrace (); j56 An6g  
} p]eD@3Wz  
} V+z)B+  
$twF93u$  
//日志 I!D*(>  
public static void log(String sMsg) v{Vesf  
{ ,ua1xsZl&  
System.err.println(sMsg); $(=1A>40  
} ]H2aYi$  
$t}1|q|  
,[L$  
public static void log(int sMsg) 7bS[\5  
{ %m3efaC  
System.err.println(sMsg); p>S/6 [X  
} "|SE#k  
} +r_[Tj|Er  
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FG:BRS<m~  
/* ppKCY4  
**TestMethod.java 1+($"$ZC&B  
*/ Beg5[4@  
package NetFox; *rT(dp!Y  
)xy6R]_b  
|vzWSm  
public class TestMethod { pN_!&#|+$  
[CX?Tt  
& jvG]>CS'  
public TestMethod() Sw'?$j^3  
{ ///xx/weblogic60b2_win.exe lJ#>Y5Qg  
try{ \S@6@UGv  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =)8fE*[s  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); l.l~K%P'h  
SiteFileFetch fileFetch = new SiteFileFetch(bean); KW^aARJ)  
fileFetch.start(); a0\UL"z#+  
} !yrHVc  
catch(Exception e){e.printStackTrace ();} 926oM77  
"@$STptkc  
&y\2:IyA  
} #"-^;Z  
yfQE8v+  
faX#KRpfd  
public static void main(String[] args) HC,@tfS  
{ f@L{*Upj+  
new TestMethod(); b%j:-^0V  
} Ya 4$7|(  
} P^W47 SO  
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