http断点续传简单实现（java)

/* &D\~-fOGb  
**SiteFileFetch.java vA10'Gx'  
*/ &$ia#j{l  
package NetFox; aF;Q
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import java.io.*; -^Baxkq(YM  
import java.net.*; \=?f4*4|
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public class SiteFileFetch extends Thread { u0^GB9q  
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SiteInfoBean siteInfoBean = null; //文件信息Bean (@vu/yN  
long[] nStartPos; //开始位置 n"Ot'1yr  
long[] nEndPos; //结束位置 '3 xvQFg  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 =1!wep"  
long nFileLength; //文件长度 ~T|?!zML  
boolean bFirst = true; //是否第一次取文件 JM0'V0z  
boolean bStop = false; //停止标志 WJ9Jj69  
File tmpFile; //文件下载的临时信息 {*bXO8vi((  
DataOutputStream output; //输出到文件的输出流 n9B1NM5 \  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 6=3}gd5  
public SiteFileFetch(SiteInfoBean bean) throws IOException osB[KRT>("  
{ ~vy_~|6s  
siteInfoBean = bean; CL5u{i5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3(Kj|u  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1C6H\;  
if(tmpFile.exists ()) $5z O=`  
{ x>8=CiUE  
bFirst = false; w^sM,c5d  
read_nPos(); @@9#odO  
}  )f>s\T  
else zjs@7LN  
{ MR=>DcR  
nStartPos = new long[bean.getNSplitter()]; zHw[`"[  
nEndPos = new long[bean.getNSplitter()]; #(FG
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} +e. bO5Y  
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} o /AEp)8  
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public void run() uli,@5%\  
{ /Li?;H  
//获得文件长度 u~=>$oT't  
//分割文件 ,~`R{,N`  
//实例FileSplitterFetch qd6XKl\5  
//启动FileSplitterFetch线程 '9>z4G*Td  
//等待子线程返回 xV @X%E  
try{ a$.(Zl  
if(bFirst) f'Dl*d  
{ v?F~fRH  
nFileLength = getFileSize(); 6H\3  
if(nFileLength == -1) .-T^S"`d|  
{ LSv0zAIe/  
System.err.println("File Length is not known!"); 0&E{[~Pv  
} Jb Hn/$  
else if(nFileLength == -2) NdZv*  
{ T52A}vf4  
System.err.println("File is not access!"); @
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} @x3x/gU  
else J)D/w[w  
{ pPem;i^~  
for(int i=0;i<nStartPos.length;i++) WBL
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{ D|} y{~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); by,"Orpwq;  
} 23BzD^2a  
for(int i=0;i<nEndPos.length-1;i++) k)oD  
{ hVo]fD|W  
nEndPos = nStartPos[i+1]; ^$c+r%9k  
} )"s <hR,  
nEndPos[nEndPos.length-1] = nFileLength; eL[BH8l  
} ,d'x]&a  
} 7Rqjf6kX`O  
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//启动子线程 H]K(`)y}4  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; )<-\ F%&b  
for(int i=0;i<nStartPos.length;i++) k;/U6,LQ*  
{ @JVax-N  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ZN
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Ll\y2oJ  
nStartPos,nEndPos,i); RZi]0l_A'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }DjW  
fileSplitterFetch.start(); QL%&b\K  
} &$ZJfHD@  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), NCbn<ojb  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); xhLVLXZ9  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]p~w`_3v  
nEndPos = " + nFileLength); i7v> 9p7  
// fileSplitterFetch[nPos.length-1].start(); BR*,E~%  
l?LwQmq6  
oY{L0B[  
//等待子线程结束 *}DCxv  
//int count = 0; & F\HR  
//是否结束while循环 Cg^=&1|  
boolean breakWhile = false; Sa7bl~p\  
8%q:lI  
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while(!bStop) sr1`/  
{ ")T;3/c  
write_nPos(); :^]rjy/|+  
Utility.sleep(500); 'M+iw:R__  
breakWhile = true; 2&7:JM~#  
H`|8x4  
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for(int i=0;i<nStartPos.length;i++) 97;`R[^J  
{ NK.]yw'  
if(!fileSplitterFetch.bDownOver) N# $ob9  
{ &g%9$*gmT  
breakWhile = false; Ry
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break; CmKbpN*  
} |X@ZM  
} LPO:Ka  
if(breakWhile) ZqH.$nXP  
break; f*U3s N^y  
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//count++; Hy}oSy26  
//if(count>4) Hz39
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// siteStop(); AlF"1X02  
} Q |,(C0<G  
=wbgZr^2  
8>Az<EF^=#  
System.err.println("文件下载结束！"); P]w5`aBM  
} "X<vgM^:  
catch(Exception e){e.printStackTrace ();} 6z(7l  
} ObJgJr  
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//获得文件长度 &[QvMh  
public long getFileSize() L[;U Z)V@  
{ WrJgU&H{  
int nFileLength = -1; =UY)U-  
try{ l12Pj02w  
URL url = new URL(siteInfoBean.getSSiteURL()); #pDWwnP[rt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /,#HGu]q'  
httpConnection.setRequestProperty("User-Agent","NetFox"); =GH>-*qp  
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2:b3+{\f  
int responseCode=httpConnection.getResponseCode(); 2ZUI~:U Z  
if(responseCode>=400) jD]Ci#|W  
{ 3Wv-olv  
processErrorCode(responseCode); (SMnYh4  
return -2; //-2 represent access is error zY_?$9l0  
} mk*r^k`a  
<!@*2/Q]J]  
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String sHeader; 39Nz>Nu:
 
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for(int i=1;;i++) ktE~)G  
{ %a\!|/;6  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); k2]fUP  
//Utility.log(in.readLine()); ]k0Pe;<  
sHeader=httpConnection.getHeaderFieldKey(i); YO&=fd*  
if(sHeader!=null) i3 ?cL4  
{ n[|*[II  
if(sHeader.equals("Content-Length")) 3(?V!y{@  
{ S)`%clN}J  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \0bao<  
break; I$yFCdXr  
} LTsX{z  
} aYy+iP'$  
else ~1xfE C/  
break; (x)}k&B;  
} y^OT0mZkg  
} QlxzWd3=q  
catch(IOException e){e.printStackTrace ();} | R\PQ/)  
catch(Exception e){e.printStackTrace ();} P_7QZ0
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Utility.log(nFileLength); >a
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return nFileLength; 5B:%##Ug5  
} *yX5g,52-|  
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//保存下载信息（文件指针位置） ?LxBH-o(  
private void write_nPos() VK)vb.:  
{ _mBFmXHHS$  
try{ Z+8Q{|Ev  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &7-ENg9 [  
output.writeInt(nStartPos.length); A[7\!bq5  
for(int i=0;i<nStartPos.length;i++) p"'knZG  
{ &|]GTN`E  
// output.writeLong(nPos); m/E$0tf  
output.writeLong(fileSplitterFetch.nStartPos); /-FvC^Fj  
output.writeLong(fileSplitterFetch.nEndPos); MP LgE.n  
} FqWW[Bgd  
output.close(); Jam&Rj,  
} ^Kbq.4  
catch(IOException e){e.printStackTrace ();} u)X]]6
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catch(Exception e){e.printStackTrace ();} :ebu8H9f%  
} NUN~T (  
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//读取保存的下载信息（文件指针位置） o&U'zaj
 
private void read_nPos() )G+D6s23  
{ s*;rt  
try{ Z=KHsMnB  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); `T#Jiq E  
int nCount = input.readInt(); 7M.TLV!f]  
nStartPos = new long[nCount]; A )q=.C#e  
nEndPos = new long[nCount]; )(/Bw&$  
for(int i=0;i<nStartPos.length;i++) Ia@!Nr2  
{ UM(`Oh8  
nStartPos = input.readLong(); JLz.lk*.  
nEndPos = input.readLong(); GEs5@EH  
} ?S8_x
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input.close(); 5$PDA*]9  
} {9c_T!c  
catch(IOException e){e.printStackTrace ();} jtH>&O  
catch(Exception e){e.printStackTrace ();} N{}o*K  
} =JW.1;  
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private void processErrorCode(int nErrorCode) QAxR'.d  
{ J/k4CV*li(  
System.err.println("Error Code : " + nErrorCode); ABIQi[A  
} LlF|VR&P.  
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//停止文件下载 `Q1;Y  
public void siteStop() h 7/wkv\y9  
{ ^[=1J  
bStop = true; I9ZJ"29  
for(int i=0;i<nStartPos.length;i++) j>I.d+  
fileSplitterFetch.splitterStop(); LLV1W0VO=P  
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} o4qB0h  
} .-mlV ^  
//负责部分文件的抓取 Qd"R@+i  
**FileSplitterFetch.java ^ZD0rp(l  
*/ 3?x}48  
package NetFox; 9O{b8=\}  
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import java.io.*; ?y|8bw<  
import java.net.*; CkeqK  
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public class FileSplitterFetch extends Thread { +\GuZ5`  
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String sURL; //File URL ":vF[6K6  
long nStartPos; //File Snippet Start Position Cj10?BNV)  
long nEndPos; //File Snippet End Position 8h{;*Wr-  
int nThreadID; //Thread's ID 1\LK[tvh  
boolean bDownOver = false; //Downing is over @tfatq+q  
boolean bStop = false; //Stop identical /I@`B2  
FileAccessI fileAccessI = null; //File Access interface Y{`hRz`  
aSMSuX8  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +rOfQ'lQ  
{ btDPP k'  
this.sURL = sURL; 52v@zDY  
this.nStartPos = nStart; A5 <T7~U  
this.nEndPos = nEnd; nK>D& S_!  
nThreadID = id; r34 GO1d  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 J]gtgt^   
} ZK?:w^Z  
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public void run() _n12Wx{  
{ FX&)~)  
while(nStartPos < nEndPos && !bStop) lfe^_`ij(+  
{ e)Pm{:E  
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Vd+5an?  
try{ G&,2>qxKR  
URL url = new URL(sURL); EWp'zbWP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); NVG`XL  
httpConnection.setRequestProperty("User-Agent","NetFox"); IEQ6J}L  
String sProperty = "bytes="+nStartPos+"-"; 12S[m~L%  
httpConnection.setRequestProperty("RANGE",sProperty); N,?D<NjXl  
Utility.log(sProperty); dY$jg  
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9 :FzSD   
InputStream input = httpConnection.getInputStream(); uTIl} N  
//logResponseHead(httpConnection); tg%C>O  
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byte[] b = new byte[1024]; Yvxp(  
int nRead; tbq_Rg7s  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }< m@82\  
{ gLQbA$gB  
nStartPos += fileAccessI.write(b,0,nRead); *h Bo,   
//if(nThreadID == 1) d
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L}.V`v{zc  
} :taRCh5  
[.*o< KP  
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Utility.log("Thread " + nThreadID + " is over!"); fH[:S9@  
bDownOver = true; !|;w(/  
//nPos = fileAccessI.write (b,0,nRead); M$AQZ')9  
} ko<VB#pOMr  
catch(Exception e){e.printStackTrace ();} pTzfc`~xv  
} '$5o5\  
} GcA!I!j/  
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//打印回应的头信息 #^;^_  
public void logResponseHead(HttpURLConnection con) Q=cbHDB  
{ WA79(B  
for(int i=1;;i++) G)wIxm$?0  
{ "K
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String header=con.getHeaderFieldKey(i); \`:
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if(header!=null) ICI8xP}a?  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *S>,5R0k  
Utility.log(header+" : "+con.getHeaderField(header)); fP 5!`8  
else ?.&?4*u  
break; tmf=1M  
} k.CHMl]  
} > [|SF%  
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public void splitterStop() uyDYS  
{ 4!r> ^a  
bStop = true; q'p>__Ox  
} dwt<s[k  
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} ;o0o6pF  
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/* N~A#itmdx  
**FileAccess.java C'$}!p70  
*//文件访问(定位，写) r
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package NetFox; G ]mX+?  
import java.io.*;  p3r1lUw  
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public class FileAccessI implements Serializable{ k^PqB+P!  
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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 Y)L\*+ >"[  
RandomAccessFile oSavedFile; 5bzYTK&-  
long nPos; WsCzC_'j.  
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public FileAccessI() throws IOException +/Lf4??JV  
{ fKY1=3  
this("",0); :4D#hOI  
} 7l})`> k  
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public FileAccessI(String sName,long nPos) throws IOException |V|)cPQ  
{ tK|hC[  
oSavedFile = new RandomAccessFile(sName,"rw"); cMEM}Qh T  
this.nPos = nPos; vAE?^*F  
oSavedFile.seek(nPos); 5B<G;if,  
} q[3b i!Q  
)>LC*_v  
u?
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public synchronized int write(byte[] b,int nStart,int nLen) #dGg !D  
{ \[+\JWJj  
int n = -1; ^JMSe-  
try{ nA]dQ+5sT  
oSavedFile.write(b,nStart,nLen); C"IP1N  
n = nLen; :;XHA8  
} ;v6e2NacM'  
catch(IOException e) Eu )7@  
{ XjwTjgL<  
e.printStackTrace (); `<>8tZS9"  
} H\3CvFm  
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 1Nk}W!v  
return n; (t9qwSS8z  
} Tj{!Fx^H  
7,e=|%7.  
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} MQ>vHapr  
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/* 5Wi5`8m  
**SiteInfoBean.java ]~(Ipz2NP  
*/ ZH%[wQ~4  
package NetFox; =fHt|}.K  
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public class SiteInfoBean { U<r<$K  
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private String sSiteURL; //Site's URL ^D B
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private String sFilePath; //Saved File's Path ;<q@>p[  
private String sFileName; //Saved File's Name zoOm[X=?3  
private int nSplitter; //Count of Splited Downloading File ?XGZp?6  
%p2C5z?  
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public SiteInfoBean() 0{PK]qp7  
{//nSplitter的缺省值为5 d<6L&8)<  
//default value of nSplitter is 5 kozg8 `\]  
this("","","",5); Ok6Y&#'P  
} [-$&pB>w8'  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^B& Z  
{ U)p2PTfB  
sSiteURL= sURL; B>Nx
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sFilePath = sPath; `s:| 4;.  
sFileName = sName; .(S,dG0P  
this.nSplitter = nSpiltter; /p>"|z  
~N'KIP[W  
XE$eHx3;  
} h)wR[N]n  
~:)$~g7>b  
:M3l#`4Q  
public String getSSiteURL() o-O/MS
 
{ XtfL{Fy|T  
return sSiteURL; u'K<-U8H  
} >/bl r}5 H  
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public void setSSiteURL(String value) \0WMb  
{ m; ABHq#  
sSiteURL = value; S|]~,l2]}  
} _i8$!b2Mr  
,(`@ZFp$  
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public String getSFilePath() I;-{#OE,  
{ ?$n<vF>  
return sFilePath; 1|gP :t}  
} KH KqE6  
&`TX4b^/!  
=_yOX=g|  
public void setSFilePath(String value) N%B#f\N  
{ 8:&@MZQ&!  
sFilePath = value; Uero!+_  
} Ew;<
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2s{yg%U(  
public String getSFileName() R9CAw>s  
{ CYrL|{M]  
return sFileName; XbH X,W$h  
} _u:#2K$  
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public void setSFileName(String value) ;JmD(T7{  
{ sG VC+!E  
sFileName = value; MJg^ QVM  
} E>g'!  
zWY6D4   
@W @L%<  
public int getNSplitter() g{J3Ba  
{ 9M7P]$^  
return nSplitter; ev?>Nq+Z  
} d;;=s=j  
)nJ>kbO~8  
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public void setNSplitter(int nCount) 2d>PN^x  
{ ifgaBXT55  
nSplitter = nCount; ~b7Nzzfo  
} s=q+3NTv  
} -xcz+pHQ  
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/* uyA9`~p=#  
**Utility.java #* Hhe>  
*/ k{bba=<  
package NetFox; F@I_sGCcb  
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public class Utility { #YNb&K n  
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public Utility() 7Ow7|  
{ =0:hrg+Zgx  
~xJD3Qf  
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} Z~nl{P#  
};+s0:H  
//线程睡眠 zyR pHM$E  
public static void sleep(int nSecond) C}>&#)IH  
{ YG8oy!Zl  
try{ g/@CESfm'  
Thread.sleep(nSecond); 67g/(4&  
} qQ_B[?+W  
catch(Exception e) =['ijD4TW  
{ UiSc*_N"  
e.printStackTrace (); ~8X'p6  
} LH_2oJ\  
} CeJ|z{F\  
 A:!{+  
//日志 >r*Zm2($MR  
public static void log(String sMsg) j;y|Ys)I  
{ c1<g!Q&E  
System.err.println(sMsg); 7/1S5yUr|  
} ?~K2&eo  
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public static void log(int sMsg) 'I~dJEW7  
{ %qQ(@TG  
System.err.println(sMsg); 4mAtYm  
} %G@aZWk Sa  
} @$*c0. |z  
a9I8WQ   
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/* "+WR[-n>\  
**TestMethod.java /7#
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*/ ?
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package NetFox; 1=X=jPwO C  
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4{?x(~  
public class TestMethod { tWiV0PTI  
bDo'hDmW  
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public TestMethod() d5\1-d_uz  
{ ///xx/weblogic60b2_win.exe op*+fJHD  
try{ 'YG`/@n;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); kT1lOP-Bg  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); VJ"3G;;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ~<%cc+;`  
fileFetch.start(); U)!AH^{32  
} 8if"U xV(  
catch(Exception e){e.printStackTrace ();} v(^rq  
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p(G?  
} uS'ji k}  
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public static void main(String[] args) =gIYa  
{ wj^I1;lO  
new TestMethod(); "Pc,+>vh  
} W24bO|>D
 
} ~roHnJ>  
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