http断点续传简单实现（java)

/* GwQZf|  
**SiteFileFetch.java qo6LC>Qg  
*/ H=&/Q  
package NetFox; 7wQ+giu  
import java.io.*; R6!cK[e]4  
import java.net.*; $>r>0S#+\&  
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public class SiteFileFetch extends Thread { JOrELrMx
 
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SiteInfoBean siteInfoBean = null; //文件信息Bean UZje>.~?  
long[] nStartPos; //开始位置 " ^HK@
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long[] nEndPos; //结束位置 dP$8JI{  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Tr8AG>  
long nFileLength; //文件长度 o
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boolean bFirst = true; //是否第一次取文件 U~:N^Sc  
boolean bStop = false; //停止标志 1Xy8|OFc[  
File tmpFile; //文件下载的临时信息 r$GPYyHK  
DataOutputStream output; //输出到文件的输出流 .tRr?*V|l  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） q=6Cc9FN  
public SiteFileFetch(SiteInfoBean bean) throws IOException Xhcn]  
{ R_1)mPQ^P  
siteInfoBean = bean; H2qf'  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); iHAU|`'N)  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); b7B+eN ?z  
if(tmpFile.exists ()) :}y9$p  
{ `$s)X$W?  
bFirst = false; (C daE!I4Q  
read_nPos(); Y5dD|]F|  
} #zON_[+s9  
else |KL')&"  
{ m\>|C1oRy  
nStartPos = new long[bean.getNSplitter()]; q0,kDM66   
nEndPos = new long[bean.getNSplitter()]; O: ,$%  
} }]AT _bh,  
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} {5^K Xj$B  
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public void run() 9G0D3F  
{ s\[L
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//获得文件长度 pzp,t(%j  
//分割文件 &+ KyPY+  
//实例FileSplitterFetch t3PtKgP-6  
//启动FileSplitterFetch线程 7vn%kW=$  
//等待子线程返回 L}'Yd'  
try{ &&=[Ivv  
if(bFirst) Cye T]y  
{ 4/S=5r}  
nFileLength = getFileSize(); vr=~M?  
if(nFileLength == -1) z{9=1XY  
{ +l`65!"  
System.err.println("File Length is not known!"); veeI==]  
} `@[l\.Vt:  
else if(nFileLength == -2) UuU/c-.  
{ -LtK8wl^  
System.err.println("File is not access!"); JB3"EFv  
} M=OCzgj  
else oM!xz1kVL  
{ f-Jbs`(+  
for(int i=0;i<nStartPos.length;i++) \v+u;6cx_  
{ bu>qsU3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); j~;;l!({i  
} bLzs?eos  
for(int i=0;i<nEndPos.length-1;i++) #B8*gFZB  
{ 9'?se5\  
nEndPos = nStartPos[i+1]; LxLy+yC#p  
} y<pnp?x4  
nEndPos[nEndPos.length-1] = nFileLength; <a4TO8  
} > _ <'D  
} =-NiO@5o  
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//启动子线程 rYY$wA@  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; {`(>O"_[Q  
for(int i=0;i<nStartPos.length;i++) .Obn&S  
{ Y4E/?37j  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <[Q3rJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :w`3cwQ  
nStartPos,nEndPos,i); g:7,~}_}^  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *4S-z&,.c  
fileSplitterFetch.start(); &gtG~mp<L  
} Q8D&tJg  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), DZ$` 4;C[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); k|vI<:'p,  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", lx |5?P  
nEndPos = " + nFileLength); ?YQPlv:<o.  
// fileSplitterFetch[nPos.length-1].start(); ,HB2hHD  
3*ixlO:qGk  
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//等待子线程结束 2o3EHZ+]cm  
//int count = 0; FOwnxYGVf  
//是否结束while循环 7%MbhlN.  
boolean breakWhile = false; :kMHRm@{  
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while(!bStop) $P z`
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{ >j*;vG5T  
write_nPos(); ^T5X)Nu{=C  
Utility.sleep(500); dY7'OAUyVl  
breakWhile = true; |4(~%| 8{  
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for(int i=0;i<nStartPos.length;i++) Jzkq)]M  
{ 0AK,&nbF  
if(!fileSplitterFetch.bDownOver) 1'.7_EQ4T  
{ j;b42G~p  
breakWhile = false; d}'U?6ob  
break; wh6yPVVF/  
} S! Rc|6y%  
} )s_n  
if(breakWhile) ({r*=wAP  
break; 1MlUG5  
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//count++; IU FH:w]  
//if(count>4) in+}/mwfC  
// siteStop(); 5r~#0Zf*  
} S$)*&46g  
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System.err.println("文件下载结束！"); <8,o50`B  
} \B F*m"lz  
catch(Exception e){e.printStackTrace ();} > f
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} dr)YzOvba  
-9N@$+T  
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//获得文件长度 ,.eWQK~  
public long getFileSize() v+p{|X-  
{ ^b:(jI*l  
int nFileLength = -1; `&\Q +W  
try{ \(226^|j  
URL url = new URL(siteInfoBean.getSSiteURL()); 'z76Sa  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !cKz7?w  
httpConnection.setRequestProperty("User-Agent","NetFox"); ? WJ> p  
CYOI.#m2  
8!.ojdyn  
int responseCode=httpConnection.getResponseCode(); QXCH(5as  
if(responseCode>=400) *6HTV0jv  
{ .MO\uh0N  
processErrorCode(responseCode); *8~86u GU  
return -2; //-2 represent access is error c/c$D;T  
} ~l;[@jsw F  
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[MuEoWrq(}  
String sHeader; G\|,5HED  
{U&.D [{&  
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for(int i=1;;i++) UK9@oCIB  
{  >S$Z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [+O"
<Ua  
//Utility.log(in.readLine()); X,9 M"E 2  
sHeader=httpConnection.getHeaderFieldKey(i); hiNEJ_f  
if(sHeader!=null) '_|h6<.k[  
{ UH3sH t  
if(sHeader.equals("Content-Length")) ~]ZpA-*@Ut  
{ (O0Urm  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Q:J^"  
break; n3J53| %v  
} s-dLZ.9F  
} JN7k2]{  
else
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break; 0uBl>A7qhn  
} {Zp\^/  
} T|tOTk  
catch(IOException e){e.printStackTrace ();} m3o,@=b  
catch(Exception e){e.printStackTrace ();} ~'R(2[L!;  
zt
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Utility.log(nFileLength); ?yh}/T\qp  
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return nFileLength; ZJlEKib%2  
} Rb\6;i8R  
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//保存下载信息（文件指针位置） V2N_8)s9W  
private void write_nPos() aF7nvu*N  
{ !ti6  
try{ k__$Q9qj(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); |ae975  
output.writeInt(nStartPos.length); qc-mGmomL  
for(int i=0;i<nStartPos.length;i++) j2 !3rI  
{ W\18{mbuy  
// output.writeLong(nPos); iDf,e Kk$'  
output.writeLong(fileSplitterFetch.nStartPos); ['ksP-=  
output.writeLong(fileSplitterFetch.nEndPos); .;&# )l
 
} f-r] |k  
output.close(); 7w3CXY  
} ^Idle*+  
catch(IOException e){e.printStackTrace ();} RxQh2<?  
catch(Exception e){e.printStackTrace ();} UUMtyf  
} }MlwC;ot  
/<rt1&0  
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//读取保存的下载信息（文件指针位置） Uo-`>7  
private void read_nPos() =~+DUMBT  
{ S/ibb&  
try{ }6 K^`!  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 5/O'R9A4  
int nCount = input.readInt(); JH8zF{?  
nStartPos = new long[nCount]; N:9>dpP}O  
nEndPos = new long[nCount]; `8FUX= Sh  
for(int i=0;i<nStartPos.length;i++) T,$WlK Wj  
{ C{d7J'Avk  
nStartPos = input.readLong(); rm} R>4  
nEndPos = input.readLong(); gR@C0  
} Zy09L}59P  
input.close(); !\g
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} "kc/J*u-3  
catch(IOException e){e.printStackTrace ();} B^^r\L9  
catch(Exception e){e.printStackTrace ();} )Jv[xY~  
} 9+keX{/c  
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private void processErrorCode(int nErrorCode) BT@r!>Nl  
{ \.g\Zib )  
System.err.println("Error Code : " + nErrorCode); :g.46dp4  
} 0VK-g}"x  
5K?}}Frrt`  
}E_#k]#*  
//停止文件下载 EJ`T$JD  
public void siteStop() nB] >!q  
{ pN
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bStop = true; U!m@DJj  
for(int i=0;i<nStartPos.length;i++) vpU#xm.K  
fileSplitterFetch.splitterStop(); 5cWw7V<m  
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} C^)
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} >YUoh-]`  
//负责部分文件的抓取 "4%"&2L  
**FileSplitterFetch.java hTbI -u7BF  
*/ .Udj@{  
package NetFox; Sc7U|s  
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import java.io.*; *kIc9}  
import java.net.*; p^iRPI  
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public class FileSplitterFetch extends Thread { SIKOFs  
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String sURL; //File URL J6<rX[ yZe  
long nStartPos; //File Snippet Start Position 4H+Ked&Oq  
long nEndPos; //File Snippet End Position h!m_PgRSs  
int nThreadID; //Thread's ID V_Wwrhua  
boolean bDownOver = false; //Downing is over V i&*&"q  
boolean bStop = false; //Stop identical {Ha8]y  
FileAccessI fileAccessI = null; //File Access interface LOTP*Syjf  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException /cZ-tSC)o  
{ ^'jEnN(  
this.sURL = sURL; N4*G{g  
this.nStartPos = nStart; ]x&u`$F  
this.nEndPos = nEnd; ~8m=1)A{(  
nThreadID = id; F,5r9^,_  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $3,ryXp7  
} iVfgDo  
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public void run() X{kpSA~  
{ +ht|N[P  
while(nStartPos < nEndPos && !bStop) Y4IGDY*  
{ KQ[!o!%  
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try{ 0 'Vg6E]/  
URL url = new URL(sURL); GjB]KA^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B4XZko(  
httpConnection.setRequestProperty("User-Agent","NetFox");
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String sProperty = "bytes="+nStartPos+"-"; tDDy]==E  
httpConnection.setRequestProperty("RANGE",sProperty); H[b}k
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Utility.log(sProperty); v_<2H'*Q  
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InputStream input = httpConnection.getInputStream(); _owjTo}  
//logResponseHead(httpConnection); 5( _6+'0
 
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 Yav2q3  
byte[] b = new byte[1024]; 1|8<H~&  
int nRead; 6bBdIqGb}  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) hO[3Z^X  
{ YK{a
 
nStartPos += fileAccessI.write(b,0,nRead); UhmTr[&  
//if(nThreadID == 1) u-"
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); AOrHU M[I  
} k n8N,,+  
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Utility.log("Thread " + nThreadID + " is over!"); }1-I[q6  
bDownOver = true; zdSh:  
//nPos = fileAccessI.write (b,0,nRead); *5,c Rz  
} mKq"34F  
catch(Exception e){e.printStackTrace ();} M2@^b
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} ~2u\  
} >5T_g2pkv  
$\AEWFB  
V,%L~dI  
//打印回应的头信息 z&4~x!-_  
public void logResponseHead(HttpURLConnection con) ,)~E
>[=+  
{ }%{MPqg  
for(int i=1;;i++) z(c9,3  
{ FbACTeB  
String header=con.getHeaderFieldKey(i); HI&kP+,y  
if(header!=null) 7.bN99{xPM  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); p2x[
p  
Utility.log(header+" : "+con.getHeaderField(header)); z2/!m[U  
else ;LJ3c7$@lf  
break; L(&}Wv  
} }gf}eH  
} cy~oPj]j  
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public void splitterStop() &~5=K  
{ ,ZI\dtl  
bStop = true; _>bRv+RVR  
} E@ h y7X  
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} \Mi#{0f+q  
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/* g8pm2o@S  
**FileAccess.java -.vDF?@G  
*//文件访问(定位，写) z
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package NetFox; p {%t q$}.  
import java.io.*; 'zgvQMu  
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public class FileAccessI implements Serializable{ nx4P^PC  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 fB#XhO  
RandomAccessFile oSavedFile; =v"xmx&4  
long nPos; lQt% Qx  
&y:CW>T$/X  
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public FileAccessI() throws IOException /! ^P)yU,  
{ rH}fLu8,;Q  
this("",0);
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} U|fTb0fB  
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public FileAccessI(String sName,long nPos) throws IOException 3;BvnD7  
{ DNth4z  
oSavedFile = new RandomAccessFile(sName,"rw"); XNmQ?`.2'  
this.nPos = nPos; +0#JnqH"  
oSavedFile.seek(nPos); mCb 9*|  
} aV|k}H{wt  
/(%Ig,<"JC  
+J40wFI:y  
public synchronized int write(byte[] b,int nStart,int nLen) 2lz {_9  
{ ic~Z_?p  
int n = -1; u:4["ViC  
try{
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oSavedFile.write(b,nStart,nLen); B82,.?  
n = nLen; FX 1C e  
} /VtlG+dLl  
catch(IOException e) rdI]\UH  
{ W'G{K\(/  
e.printStackTrace (); -931'W[s,  
} U(3(ZqP  
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IgA.%}II}  
return n; aiR5/ ZD  
} %AgA -pBp  
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\L#QR  
} Hd*Fc=>"Y  
_sm;HH7'*  
nhT;b,G.Z  
/* UG=I~{L  
**SiteInfoBean.java S2}Z&X(  
*/ qhwoV4@f  
package NetFox; 4@))OD^x  
d qpgf@  
)[ w&C_>]  
public class SiteInfoBean { {tmKCG  
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private String sSiteURL; //Site's URL cI3KB-lM#  
private String sFilePath; //Saved File's Path e7's)C>/'  
private String sFileName; //Saved File's Name .S6ji~;r  
private int nSplitter; //Count of Splited Downloading File n\*JaY  
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public SiteInfoBean() DOT=U _  
{//nSplitter的缺省值为5 Rj&qh`  
//default value of nSplitter is 5 -+ko}He  
this("","","",5);
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} W{\EE[XhCf  
}"0{zrz  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) SLg+H  
{ kI<WvgoL  
sSiteURL= sURL; u'=(&><  
sFilePath = sPath; V 1*Ad  
sFileName = sName; v*vn<nPAQ>  
this.nSplitter = nSpiltter; tw-fAMwU  
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} =hPG_4#  
RP(a,D|  
U @)k3^
 
public String getSSiteURL() -E}>h[;qZ  
{ ia_Z\q  
return sSiteURL; IO*l vy  
} ?Q;kZmQl  
%N>\:85?  
+8^5C,V  
public void setSSiteURL(String value) bI#<Ee0nJ  
{ eQ$e*|}"m  
sSiteURL = value; ) b
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} luibB&p1  
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public String getSFilePath() eN2dy-0  
{ oPCrD.s  
return sFilePath; ix^gA
ot  
} "/Om}*VhD  
6g}^Q?cpV#  
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public void setSFilePath(String value) ;i.I&*t  
{ ';&0~[R[  
sFilePath = value; Q! Kn|mnN  
} )@!~8<_"  
HOq4i!  
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public String getSFileName() UOw~rK   
{ |3S'8OeCI  
return sFileName;  NvUu
.  
} ud yAP>  
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public void setSFileName(String value) qC\]"Z`m  
{ n"mJEkHE  
sFileName = value; T~s&)wD  
} {a]pF.^kf  
nDyvX1]  
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public int getNSplitter() >~h>#{&  
{ L^3~gM"!  
return nSplitter; 3b+7^0frY#  
} PP!l  
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public void setNSplitter(int nCount) GXarUjs  
{ Yr5iZ~V$  
nSplitter = nCount; {EOn
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} C5>{Q:.`e'  
} ftO+.-sm<  
{-o7w0d_  
M`)s>jp@w  
/* ;&K3[;a  
**Utility.java #D= tX  
*/ P\,F1N_?r  
package NetFox; tDEXm^B2Sv  
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public class Utility { FTbT9   
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public Utility() }Vs~RJM)}  
{ \k|_&hG  
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} BXT80a\  
n"XdHW0  
//线程睡眠 Tq9,c#}&  
public static void sleep(int nSecond) %|#P&`  
{ P=f<#l"v  
try{ F"-S~I7'L  
Thread.sleep(nSecond); NdM}xh  
} p^p'/$<6_  
catch(Exception e) WA<H  
{ mw:3q6  
e.printStackTrace (); )W[KD,0+j  
} 'u4}t5Bu5  
} `K$:r4/[  
)3k)2XF  
//日志 FI3sLA  
public static void log(String sMsg) K.:6YXVs<  
{ ;[?J5X,  
System.err.println(sMsg); |hu"5*  
} 7'-)/Pk  
Iu)L3_+  
9c"0~7v  
public static void log(int sMsg) cFRSd }p=  
{ ~+nS)4(  
System.err.println(sMsg);  ~Y1"k]J  
} Hi9 G^Q  
} B$K7L'e+-  
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/* Q'FX:[@x-S  
**TestMethod.java DH}s1mNMP  
*/ uU8*$+ "  
package NetFox; I'KR'1z 9  
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#]?,gwvTf  
public class TestMethod { o%kSR ]V|  
gg lNpzj  
~J8cS  
public TestMethod() k$9Gn9L%  
{ ///xx/weblogic60b2_win.exe 2N6Pa(6  
try{ [{6&.v  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); pKOT Qf  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); )OARO  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -=-x>(pRW7  
fileFetch.start(); Jm{As*W>  
} R*JOiVAC  
catch(Exception e){e.printStackTrace ();} S#dyRTmI  
, I[^3Fn  
27h/6i3  
} t9KH|y  
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public static void main(String[] args) ]=$-B  
{ pHI%jHHJ  
new TestMethod(); f)&`mqeE  
} r?Ev.m  
} `~w%Jf  
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