http断点续传简单实现（java)

/* P*o9a  
**SiteFileFetch.java 3sk9`=[{$  
*/ 0`hdMLONR  
package NetFox; n*$ g]G$  
import java.io.*; Je{ykL?N  
import java.net.*; v2?ZQeHr_(  
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public class SiteFileFetch extends Thread { W4N{S.#!  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 6wxs1G  
long[] nStartPos; //开始位置 *8Z32c+C  
long[] nEndPos; //结束位置 ;bG>ZqJCVA  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 {8OCXus3m  
long nFileLength; //文件长度 :-'qC8C  
boolean bFirst = true; //是否第一次取文件 ]{iQ21`a-  
boolean bStop = false; //停止标志 $C\BcKlmv  
File tmpFile; //文件下载的临时信息 4Up/p&1@  
DataOutputStream output; //输出到文件的输出流 MJvp6n  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） C]#,+q*  
public SiteFileFetch(SiteInfoBean bean) throws IOException PM+[,H  
{ $?Wb}DU7_L  
siteInfoBean = bean; PeT'^?>  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6 r"<jh#  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ise-O1'  
if(tmpFile.exists ()) "fI6Cpc  
{ ?EL zj  
bFirst = false;
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read_nPos(); _LPHPj^Pg  
} xwr8`?]y  
else "8RSvT<W^5  
{ /\Ef%@  
nStartPos = new long[bean.getNSplitter()]; 9UkBwS`  
nEndPos = new long[bean.getNSplitter()]; E3i4=!Y  
} ~V-XEQA  
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} z}@7'_iJ  
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public void run() ?0SEMmp`H  
{ *Uh!>Iv;  
//获得文件长度 RpK@?[4s  
//分割文件 sRW<me;  
//实例FileSplitterFetch K8~d^
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//启动FileSplitterFetch线程 +:f"Y0  
//等待子线程返回 hc1N~$3!G  
try{ `gJ(0#ac  
if(bFirst) SIllU  
{ yr6V3],Tp  
nFileLength = getFileSize(); "zc l|@  
if(nFileLength == -1) R=dC4;  
{ O=lzT~G|4  
System.err.println("File Length is not known!"); ?(PKeq6  
} nu^436MSOa  
else if(nFileLength == -2) ]yu:i-SfP  
{ a}d@ T  
System.err.println("File is not access!"); d1
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} ebq4g387X  
else nNm`
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{ 4W])}C%  
for(int i=0;i<nStartPos.length;i++) qLCR] _*  
{ 2|,VqVb  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); DqPw#<"H  
} -} +[  
for(int i=0;i<nEndPos.length-1;i++) u!s2BC0}N  
{ ~@!bsLSMU  
nEndPos = nStartPos[i+1]; .6> w'F{>  
} R/_&m$ZB  
nEndPos[nEndPos.length-1] = nFileLength; %C0Dw\A*:  
} ibw;}^m(  
} L-Lvp%%  
>usL*b0%  
==B6qX8T  
//启动子线程 ,I9bNO,%JK  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; BWNi [^]  
for(int i=0;i<nStartPos.length;i++) >eaaaq9B-  
{ so; ]&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), G5!^*jf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \^LFkp  
nStartPos,nEndPos,i); <$YlH@;)`a  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vIvIfE  
fileSplitterFetch.start(); "N;EL0=  
} YQ}o?Q$z  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Fcx&hj1gQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); }qUX=s GG  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", jo7\`#(Q  
nEndPos = " + nFileLength);
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// fileSplitterFetch[nPos.length-1].start(); LP-o8c  
=AT."$r>  
b$7 +;I;  
//等待子线程结束 IgzQr>  
//int count = 0; zqku e%^?-  
//是否结束while循环 7^285)UQA  
boolean breakWhile = false; NHt\ U9l'  
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while(!bStop) 3^ClAE"8  
{ 7=uj2.J6  
write_nPos(); JT?h1v<H]  
Utility.sleep(500); WAqINLdX  
breakWhile = true; [Pp'Ye~K@c  
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for(int i=0;i<nStartPos.length;i++) yauvXosX  
{ /QQ*8o8  
if(!fileSplitterFetch.bDownOver) pCDmXB  
{ +3gp%`c4  
breakWhile = false; =wJX0A|  
break; K"6vXv4QO  
} iscz}E,Y  
} #Z#-Ht  
if(breakWhile) sA~]$A;DM!  
break; mq l Z?-  
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//count++; i%/+5gq  
//if(count>4) x;S @bY  
// siteStop(); S/ *E,))m  
} gUlo]!$  
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System.err.println("文件下载结束！"); wkq 
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} y-k.U%  
catch(Exception e){e.printStackTrace ();} [0of1eCSl  
} v19-./H^ j  
4*L_)z&4;  
@~e5<:|5#  
//获得文件长度 DXo|.!P=3  
public long getFileSize() #E?4E1bnB  
{ %>yL1BeA4  
int nFileLength = -1; \+etCo   
try{ #WuBL_nZ~  
URL url = new URL(siteInfoBean.getSSiteURL()); `uFdwO'DD  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {ax:RUQxy  
httpConnection.setRequestProperty("User-Agent","NetFox"); b}f~il  
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int responseCode=httpConnection.getResponseCode();
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if(responseCode>=400) ~&T~1xsFJ  
{ 8}[).d160  
processErrorCode(responseCode); XX@ZQcN  
return -2; //-2 represent access is error T%Lx%Qn  
} .>S!ji  
do%&m]#;  
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String sHeader; .H|-_~Yx|  
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for(int i=1;;i++) +0&/g&a\R  
{ #R"*c hLV  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); p?!/+  
//Utility.log(in.readLine()); xAr\gu  
sHeader=httpConnection.getHeaderFieldKey(i); 8mMQ[#0:}  
if(sHeader!=null) Ulyue  
{ H)?z #x  
if(sHeader.equals("Content-Length")) h\o.&6sd  
{ s*[bFJwN  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8Wx=p#_  
break; %;_MGae  
} UpG~[u)%@  
} \<' ?8ri#  
else L#J1b!D&<6  
break; fl(wV.Je|  
} .3;;;K9a~]  
} uph(V  
catch(IOException e){e.printStackTrace ();} *T/']t  
catch(Exception e){e.printStackTrace ();} #4PN"o@  
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6'/ #+,d'  
Utility.log(nFileLength); _U(  
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return nFileLength; =euni}7a  
} +rd+0 `}C  
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//保存下载信息（文件指针位置） 8=l%5r^cq  
private void write_nPos() kj_c%T ]/  
{ ,prf;|e?  
try{ Upe%r
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output = new DataOutputStream(new FileOutputStream(tmpFile)); u_enqC3  
output.writeInt(nStartPos.length); ? t|[?  
for(int i=0;i<nStartPos.length;i++) nUO0Ce
 
{ 2ESo2  
// output.writeLong(nPos); ]DcFySyv  
output.writeLong(fileSplitterFetch.nStartPos); r;{.%s7  
output.writeLong(fileSplitterFetch.nEndPos); RP"kC4~1  
} aOp\91  
output.close(); wT@og|M  
} d-qUtgqV86  
catch(IOException e){e.printStackTrace ();} K-4PI+qQ\  
catch(Exception e){e.printStackTrace ();} _b 0&!l<  
} n S=W1zf  
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//读取保存的下载信息（文件指针位置） d0D]Q  
private void read_nPos() Psf#c:*_)  
{ ;pAK_>
 
try{ +>,I1{u%&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *w&e\i|7  
int nCount = input.readInt(); K0~rN.C!0  
nStartPos = new long[nCount]; ?4,T}@P  
nEndPos = new long[nCount]; 1?}T=)3+$  
for(int i=0;i<nStartPos.length;i++) DQ3<$0  
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nStartPos = input.readLong(); h{Y",7]!  
nEndPos = input.readLong(); N7"W{"3D  
} h`q1  
input.close(); s;e\ pt  
} tw;}jh  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} [JiH\+XLPs  
} f|5co>Hk  
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private void processErrorCode(int nErrorCode) X'srL j.  
{ dV_G1'  
System.err.println("Error Code : " + nErrorCode); ?`s8 pPc4  
} e6*8K@LHB  
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//停止文件下载 RZLq]8pM  
public void siteStop() FrS]|=LJhX  
{ U
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bStop = true; @"A4$`Xi3  
for(int i=0;i<nStartPos.length;i++) oR'm2d^  
fileSplitterFetch.splitterStop(); [,Gg^*umS  
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} @ Y+oiB~Y  
} -w2/w@&  
//负责部分文件的抓取 J1k>07}
|  
**FileSplitterFetch.java K-v#.e4  
*/ D*jM1w_`  
package NetFox; t.<i:#rj>l  
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import java.io.*; Wr 4,YQM  
import java.net.*; XFl6M~ c  
>MZ/|`[M  
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public class FileSplitterFetch extends Thread { <'u'#E@"sl  
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String sURL; //File URL y29m/i:  
long nStartPos; //File Snippet Start Position P.cyO3l  
long nEndPos; //File Snippet End Position -?\D\\+t  
int nThreadID; //Thread's ID @ArSC  
boolean bDownOver = false; //Downing is over Jy)/%p~  
boolean bStop = false; //Stop identical O.? JmE  
FileAccessI fileAccessI = null; //File Access interface Gc?a+T  
_BufO7`.  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException MgZ/(X E  
{ 4#D,?eA7  
this.sURL = sURL; dtDFoETz  
this.nStartPos = nStart; /ZX}Nc g  
this.nEndPos = nEnd; '1[Ft03  
nThreadID = id; cAw/I@jG  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Yy8g(bU  
} 4W75T2q#  
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public void run() /vt3>d%B;  
{ F,kZU$  
while(nStartPos < nEndPos && !bStop) F59 TZI  
{ W9&=xs6  
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try{ l
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URL url = new URL(sURL); WJi]t93  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "+c-pO`Wg  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4g/d
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String sProperty = "bytes="+nStartPos+"-"; mpyt5#f  
httpConnection.setRequestProperty("RANGE",sProperty); y_)FA"IkE  
Utility.log(sProperty);
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66}  
InputStream input = httpConnection.getInputStream(); !WlH'y-I  
//logResponseHead(httpConnection); 6]N.%Y[(  
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byte[] b = new byte[1024]; }p V:M{Nu&  
int nRead; /r 5eWR1G  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) y =@N|f!  
{ sW$XH1Uf#  
nStartPos += fileAccessI.write(b,0,nRead); 0RfZEG)  
//if(nThreadID == 1) u*R_\*j@  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); z:O8Ls^\T  
} >_} I.\X  
}H2R3icE  
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Utility.log("Thread " + nThreadID + " is over!"); 3|7QUld  
bDownOver = true; %<5'=t'|-U  
//nPos = fileAccessI.write (b,0,nRead); 4i bc  
} xw%0>K[  
catch(Exception e){e.printStackTrace ();} 7)m9"InDI  
} y`F
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} !>tL6+yj  
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//打印回应的头信息 2%1hdA<  
public void logResponseHead(HttpURLConnection con) rqq1TRg  
{ :k"]5>(^  
for(int i=1;;i++) *hrd5na  
{ 1YA% -~  
String header=con.getHeaderFieldKey(i); ;S{(]K7i  
if(header!=null) '-6~tWC~7  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); U*:!W=XN  
Utility.log(header+" : "+con.getHeaderField(header)); g0H[*"hj  
else 'qi}|I  
break; P>L +t`'  
} 58K5ZZG  
} RSds8\tk  
)jj0^f1!j  
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public void splitterStop() )0MB9RMk1  
{ GILfbNcd  
bStop = true; }G=M2V<L  
} X]=t>
 
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} )"LJ hLg  
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/* jpOp
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**FileAccess.java PFR:>^wK2  
*//文件访问(定位，写)
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package NetFox; l%ZhA=TKQ  
import java.io.*; J1kM\8%b\  
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public class FileAccessI implements Serializable{ l0] EX>"E  
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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 wzaV;ac4K  
RandomAccessFile oSavedFile; j|n R"!  
long nPos; VpUAeWb  
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public FileAccessI() throws IOException >7r!~+B"9'  
{ ,[Fb[#Qqb  
this("",0); l,:F  
} Q&&@v4L  
m*;ERK  
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public FileAccessI(String sName,long nPos) throws IOException hSMH,^Io$  
{ [Q =Nn  
oSavedFile = new RandomAccessFile(sName,"rw"); "3hMq1NQ`g  
this.nPos = nPos; *A< 5*Db:F  
oSavedFile.seek(nPos); F?cK-.  
} }Lv;

!  
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public synchronized int write(byte[] b,int nStart,int nLen) :4s1CC+@\  
{ _
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int n = -1; 1}37Q&2  
try{ M;NX:mX9  
oSavedFile.write(b,nStart,nLen); 6RM/GM  
n = nLen; Ie^l~G
b  
} f5k6`7Vj]  
catch(IOException e) =EIkD9u  
{ $N\Ja*g  
e.printStackTrace (); mTh]PPo
 
} zJXplvaL;  
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return n; uM
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} *kVV+H<X|b  
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} 2Hdu:"j  
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/* OH"XrCX7n  
**SiteInfoBean.java e%6QTg5#  
*/ &?vgP!d&M  
package NetFox; i&k7-<  
vj*%Q(E6Pt  
P&q7|ST%N  
public class SiteInfoBean { cFv8 Od  
qVPeB,kIz  
r
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private String sSiteURL; //Site's URL CNIsZv@Q  
private String sFilePath; //Saved File's Path h1{3njdr  
private String sFileName; //Saved File's Name ~v83pu1!2s  
private int nSplitter; //Count of Splited Downloading File 5?L<N:;J_  
KU;9}!#  
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public SiteInfoBean() )jC%a6G!  
{//nSplitter的缺省值为5 875od  
//default value of nSplitter is 5 X(C$@N  
this("","","",5); *j-aXN/$  
} &0f,~ /%Z  
dTtSUA|V7"  
2JFpZU"1  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 2-b6gc7  
{ &OBkevg  
sSiteURL= sURL; MW{8VH6+  
sFilePath = sPath; T>GM%^h,7-  
sFileName = sName; o14cwb  
this.nSplitter = nSpiltter; 4OX^(  
_ J[
  
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} |)81
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{iLT/i%  
s{" 2L{,$  
public String getSSiteURL() d7i]FV  
{ X7wKy(g  
return sSiteURL; O~QB!<Q+  
} `XB 9Mi=  
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$A`VYJtt#  
public void setSSiteURL(String value) fX+O[j  
{ 0^ibNiSP  
sSiteURL = value; '\GbmD^F  
} Lp7SLkwh3M  
m`_ONm'T&  
4aY|TN/|  
public String getSFilePath() d/Q%IeEL.  
{ )ANmIwmC#  
return sFilePath; [9 RR8  
} EZj9wd"u  
3Y~>qGQwh  
9K&:V(gmw  
public void setSFilePath(String value) h}EPnC}  
{ rbCAnwA2  
sFilePath = value; 7yba04D)
 
} Lxk[;j+  
rD>f|kA?L  
B]$GSEB  
public String getSFileName() <|\Lm20G]  
{ +]50DxflA  
return sFileName; Yuc> fFA  
} c=+!>Z&i$G  
)0R'(#  
)Beiu*  
public void setSFileName(String value) `#gie$B{  
{ <o= 8FO  
sFileName = value; veRm2LSP  
} h-D}'R  
+U.I( 83F  
7!$^r$t  
public int getNSplitter() -tNUMi'  
{ !YJs]_Wr  
return nSplitter; T n}s*<=V  
} |&[EZ+[  
6_ow%Rx~F  
=>dGL|  
public void setNSplitter(int nCount) <rmvcim{*  
{ lA-h`rl/  
nSplitter = nCount; l0hlM#  
} _7)n(1h[3b  
} ->{KVPHe{  
+H2-ZXr  
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/* -S+zmo8  
**Utility.java {u9}bx'<  
*/ uOGw9O-d9  
package NetFox; ilva,WFa^  
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public class Utility { _Y[bMuUb=  
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(%:c#;#  
public Utility() 9<)NvU^-r  
{ ~3S~\0&|  
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} c7E11 \%&Z  
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//线程睡眠 )tnh4WMh}  
public static void sleep(int nSecond) ?KI,cl  
{ a -moI+y  
try{ F.v{-8GV  
Thread.sleep(nSecond); 1&o|TT/  
} UOmY-\ &c  
catch(Exception e) @oad,=R&  
{ UEVG0q
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e.printStackTrace (); 63~ E#Dt4  
} 9?3&?i2-  
} I15{)o(8$  
c\V7i#u[d;  
//日志 )@'}\_a3[]  
public static void log(String sMsg) C=4Qlt[`  
{ ,<p}o\6  
System.err.println(sMsg); u4|$bbig  
} y<bDTeoo  
Iy3GE[  
7 ^mL_SMj  
public static void log(int sMsg) FtC^5{V+V  
{ r{%qf;  
System.err.println(sMsg); >u8gD6X  
} *C=>X193U  
} *U\`CXn;  
;l-!)0U  
&q|K!5[k  
/* }XM(:|8J,  
**TestMethod.java x7x\Y(@  
*/ 1|6%evPu(  
package NetFox; nL.<[]r  
J{&H+rd  
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public class TestMethod { =6|&Jt  
g^ i&gNDx  
; p{[1  
public TestMethod() _W'-+,  
{ ///xx/weblogic60b2_win.exe \A6B,|@  
try{ :'&brp3ii=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); E'.7xDN  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 3CGp`~Zf  
SiteFileFetch fileFetch = new SiteFileFetch(bean); a,#j =  
fileFetch.start(); B[?CbU  
} Y,e B|  
catch(Exception e){e.printStackTrace ();} 0|\$Vp  
Uwx E<=z  
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} 1,!(0 5H  
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 XJ5.  
public static void main(String[] args) ,V:SN~P66+  
{ ^J8lBLqe  
new TestMethod(); ~Ti'FhN  
} bl(RyAgA  
} j;iAD:nf  
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