http断点续传简单实现（java)

/* V$;`#J$\b  
**SiteFileFetch.java k6Vs#K7a  
*/ | z_av  
package NetFox; w^n&S=E E~  
import java.io.*; =knLkbiq7,  
import java.net.*; YcR: _ac  
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public class SiteFileFetch extends Thread { G&MO(r}B  
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SiteInfoBean siteInfoBean = null; //文件信息Bean \$t{K  
long[] nStartPos; //开始位置 NwQ$gDgu t  
long[] nEndPos; //结束位置 ";jAHGbO  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 D&@ js!|5  
long nFileLength; //文件长度 -;RAW1]}Y$  
boolean bFirst = true; //是否第一次取文件 eb,QT\/G  
boolean bStop = false; //停止标志 R$MR|
 
File tmpFile; //文件下载的临时信息 &hi
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DataOutputStream output; //输出到文件的输出流 +9')G-`qj  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） rq1~%S  
public SiteFileFetch(SiteInfoBean bean) throws IOException K:Z,4Y  
{ A)d0Z6G`  
siteInfoBean = bean; )=aqj@v  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); */TO$ ^s  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Ae2Y\sAV  
if(tmpFile.exists ()) <S;YNHLC  
{ XRyeEwA;pp  
bFirst = false; kI5LG6  
read_nPos(); 3W.D^^)eCV  
} d~QJ}a  
else *tkf)[(  
{ -GQ.B{%G
 
nStartPos = new long[bean.getNSplitter()]; T2mZkK?rA  
nEndPos = new long[bean.getNSplitter()]; =&qfmq  
} ANj%q9e!Yi  
#-R]HLW*  
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} YYkgm:[  
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public void run() >Yv#t.!  
{ Qt^6w}&  
//获得文件长度
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//分割文件 /8hjs{(;  
//实例FileSplitterFetch b+Vlq7Bc  
//启动FileSplitterFetch线程 p!?7;  
//等待子线程返回 oW(8bd)  
try{ q?L*Luu+  
if(bFirst) wJvk  
{ `fVzY"Qv k  
nFileLength = getFileSize(); cRf;7G  
if(nFileLength == -1) AO5a  
{ HJ!)&xT  
System.err.println("File Length is not known!"); Esg:  
} 2elj@EB,M  
else if(nFileLength == -2) F[.IF5_  
{ gK dNgU  
System.err.println("File is not access!"); "[Tr"nI  
} wc~9zh  
else E!I4I'  
{ i@<w"yNd_  
for(int i=0;i<nStartPos.length;i++)
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{ gKIN* Od  
nStartPos = (long)(i*(nFileLength/nStartPos.length));
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} H-X5A\\5  
for(int i=0;i<nEndPos.length-1;i++) =aehhs>  
{ O&">%aU1I  
nEndPos = nStartPos[i+1]; v57Kr ,  
} (ijO|%?  
nEndPos[nEndPos.length-1] = nFileLength; MUN:}S  
} bs?4|#[K  
} *S Z]xrs  
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//启动子线程 "DJ%Yo  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; r&L1jT.  
for(int i=0;i<nStartPos.length;i++) Vr&v:8:wb  
{ z:{R4#(Q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), tfe'].uT  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Z@Qf0 c  
nStartPos,nEndPos,i); 2"Y=*s  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8R;E
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fileSplitterFetch.start(); BMhuM~?(  
} rmI@ #'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;:
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); q93V'[)F  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", `]Vn[^?D  
nEndPos = " + nFileLength); $,T3vX]<  
// fileSplitterFetch[nPos.length-1].start(); gJzS,g1]  
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//等待子线程结束 er!+QD,EM  
//int count = 0; CR|>?9V  
//是否结束while循环 `R$bx 64  
boolean breakWhile = false; O}7aX '  
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while(!bStop) RWn#"~  
{ "xD5>(|^+Q  
write_nPos(); !|Y&h0e  
Utility.sleep(500);
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breakWhile = true; bHHR^*B  
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for(int i=0;i<nStartPos.length;i++) `"bp-/  
{ ;[Hrpl S  
if(!fileSplitterFetch.bDownOver) R"PO@v  
{ Q@UY4gA'  
breakWhile = false; q{)Q ?E  
break; %E2C4UbY  
} .>(qZEF  
} E95VR?nUg  
if(breakWhile) ?Ye%k  
break; ]O+Nl5*  
sF#t{x/sW  
;!>>C0s"  
//count++; /3~}=b  
//if(count>4) sZU Ao&  
// siteStop(); tLx8}@X"  
} ]}AyDy6C  
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System.err.println("文件下载结束！"); 9, 792b  
} N{zou?+  
catch(Exception e){e.printStackTrace ();} E`uK7 2j  
} /s`xPxvt  
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//获得文件长度 B&H [z  
public long getFileSize() TC'^O0aZ_  
{ wijY]$  
int nFileLength = -1; 
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try{ .s@[-! p  
URL url = new URL(siteInfoBean.getSSiteURL()); #.\X%!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9'JkLgz;d+  
httpConnection.setRequestProperty("User-Agent","NetFox"); DzCb'#   
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int responseCode=httpConnection.getResponseCode(); 2O9OEZdKB  
if(responseCode>=400) i{/nHrN  
{ woK?td|/  
processErrorCode(responseCode); HLM"dmI   
return -2; //-2 represent access is error = G3A}  
} y|Zj M  
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String sHeader; ~wRozV  
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for(int i=1;;i++) Aaix? |XN  
{ GpM_Qp  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); J)Td'iT(  
//Utility.log(in.readLine()); vweD{\b  
sHeader=httpConnection.getHeaderFieldKey(i); =").W\,  
if(sHeader!=null) eM`"$xc Oe  
{ aA.TlG@zP  
if(sHeader.equals("Content-Length")) y<5xlN(+v  
{ uM~j  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); #/`V.jXt>  
break; M3 $MgsN:  
} LHP?!rO0  
} $rE_rZ+]="  
else l,3[hx  
break; 5bKn6O)K  
} Ss7XjWP.}  
} *,DBRJ_*7  
catch(IOException e){e.printStackTrace ();} -n~VMLd?@  
catch(Exception e){e.printStackTrace ();} 1{S" axSL  
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b}r3x&)  
Utility.log(nFileLength); Djf,#&j!3  
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return nFileLength; yS-owtVCGF  
} Au/n|15->C  
1%6}m`3  
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//保存下载信息（文件指针位置） sxLq'3(  
private void write_nPos() ZK]C!8\2|  
{ |bz,cvlP W  
try{ ]={{$}8.  
output = new DataOutputStream(new FileOutputStream(tmpFile)); bdCpGG9  
output.writeInt(nStartPos.length); -.E<~(fad  
for(int i=0;i<nStartPos.length;i++) hw&R.F  
{ *l^%7Wrk  
// output.writeLong(nPos); 4<&`\<jZ  
output.writeLong(fileSplitterFetch.nStartPos); qcfLA~y  
output.writeLong(fileSplitterFetch.nEndPos); _#+~#U%5n  
} Kq';[Yc  
output.close(); L1k_AC1.M
 
} <[7.+{qfW  
catch(IOException e){e.printStackTrace ();} f"5vpU^5*  
catch(Exception e){e.printStackTrace ();} [nlW}1)46  
} QY<2i-A  
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//读取保存的下载信息（文件指针位置） 6^.<5SJ}  
private void read_nPos() `=Hh5;ep  
{ L%JmdY;  
try{ xGeRoW(X  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .Eg>)  
int nCount = input.readInt(); X@)5F 9  
nStartPos = new long[nCount]; e? fFh,a  
nEndPos = new long[nCount]; K/jC>4/c/  
for(int i=0;i<nStartPos.length;i++) igsJa1F  
{ g%Ap<iT  
nStartPos = input.readLong(); /E@|  
nEndPos = input.readLong(); T0Q)}%L  
} ,m:YZ;J(Xd  
input.close(); 2, ` =i
 
} eUA6X ,I  
catch(IOException e){e.printStackTrace ();} u%S&EuX  
catch(Exception e){e.printStackTrace ();} A|8(3PiP  
} =x~HcsJ8!R  
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private void processErrorCode(int nErrorCode) PK5xnT:  
{ w7]@QTC  
System.err.println("Error Code : " + nErrorCode); Sf)VQ5U!Y  
} 2mbZ6'p {  
(<pc4#B@*  
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//停止文件下载 QOkPliX  
public void siteStop() l=ZhHON  
{ Dm[4`p@IY\  
bStop = true; jYRwtP\  
for(int i=0;i<nStartPos.length;i++) #!KbqRt  
fileSplitterFetch.splitterStop(); .Kr?vD^nG  
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} K<KyX8$P0  
} .S17O
}  
//负责部分文件的抓取 m6)8L?B   
**FileSplitterFetch.java 9Bl_t}0  
*/ k#%BxT  
package NetFox; mh!;W=|/"  
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import java.io.*; x5k6yHn  
import java.net.*; %^g BDlR^  
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public class FileSplitterFetch extends Thread { TDdFuO'}  
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String sURL; //File URL ^PfFW  
long nStartPos; //File Snippet Start Position [Zk|s9  
long nEndPos; //File Snippet End Position _gjsAbM  
int nThreadID; //Thread's ID cTFyF)  
boolean bDownOver = false; //Downing is over rE-Xv. |
 
boolean bStop = false; //Stop identical yK<%AV@v  
FileAccessI fileAccessI = null; //File Access interface utC]GiR  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _mKO4Atw  
{ S,EXc^
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this.sURL = sURL; -82Rz   
this.nStartPos = nStart; zo&'2I  
this.nEndPos = nEnd;  [ottUS@  
nThreadID = id; &)OX*y  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ._"U{ f2V  
} eZ y)>.6Z  
 ;OQ{  
<SUjz}_Oa:  
public void run() l njaHol0  
{ tB4- of3+  
while(nStartPos < nEndPos && !bStop) a5:Q%F<!  
{ %lAJ]$m  
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try{ ~oh=QakW  
URL url = new URL(sURL); -@-cG\{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2P~zYdjS  
httpConnection.setRequestProperty("User-Agent","NetFox"); M;={]w@n  
String sProperty = "bytes="+nStartPos+"-"; \aQBzEX  
httpConnection.setRequestProperty("RANGE",sProperty); ]L%qfy4  
Utility.log(sProperty); jm'(t=Ze  
cOthq87:  
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InputStream input = httpConnection.getInputStream(); &Jv j@,>$d  
//logResponseHead(httpConnection); @kn0f`  
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byte[] b = new byte[1024]; &aldnJ  
int nRead; /pZLt)=P  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Xz&Hfs"/J  
{
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nStartPos += fileAccessI.write(b,0,nRead); kN>%y&cK  
//if(nThreadID == 1) c%
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }kdYR#{s  
} v{^_3 ]  
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Utility.log("Thread " + nThreadID + " is over!"); ZFNM>C^  
bDownOver = true; 2j`x^  
//nPos = fileAccessI.write (b,0,nRead); DTk)Y-eQ  
} \T'uFy9&a  
catch(Exception e){e.printStackTrace ();} 4:=']C  
} h}i /u  
} Pfu2=2Ra  
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//打印回应的头信息 g8 ,V( ^  
public void logResponseHead(HttpURLConnection con) RyKsM.   
{ V03U"eI="  
for(int i=1;;i++) ttuQ,SD  
{ 4<)%Esyb  
String header=con.getHeaderFieldKey(i); b"t95qlL  
if(header!=null) iXK.QktHw  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ilEWxr;,  
Utility.log(header+" : "+con.getHeaderField(header)); 3:7J@>  
else -z./6dQ  
break; :TqvL'9o  
} j{SRE1tqh  
} {$)zC*l  
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public void splitterStop() p<*3mbgGO  
{ -gefdx6ES  
bStop = true; F]\(p=U.  
} s3kHNDdC  
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} $Mm=5K%  
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B>*zQb2:  
/* "<H.F87Z)  
**FileAccess.java -"[o|aa^  
*//文件访问(定位，写) y{+$B Y$_  
package NetFox; :2iNw>z1  
import java.io.*; h`X)sC+  
j}3Avu%  
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public class FileAccessI implements Serializable{ Gf(hN|X.  
Q;W[$yv
W  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 O|=5+X  
RandomAccessFile oSavedFile; x1</%y5ev  
long nPos; {m~.'DU  
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c[J(H,mt/  
public FileAccessI() throws IOException A}pmr  
{ ggtGecKm  
this("",0); ?TA%P6Lw  
} _^;+_6&[  
QPB@qx#@  
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public FileAccessI(String sName,long nPos) throws IOException Osncl5PD)  
{ sS(t }$  
oSavedFile = new RandomAccessFile(sName,"rw"); )zz^RB\p  
this.nPos = nPos; H6%QM}t  
oSavedFile.seek(nPos); b9Jah  
} ]Ir{9EE v  
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(T:OZmEO.  
public synchronized int write(byte[] b,int nStart,int nLen) jA_wOR7$  
{ !D6  
int n = -1; 
/RU'~(  
try{ qpzzk9ba[  
oSavedFile.write(b,nStart,nLen); GSo&$T;B6  
n = nLen; l]t9*a]a  
} jN 9|q  
catch(IOException e) "&;8U.  
{ n "?It  
e.printStackTrace (); n+1!/H=d  
} $BHbnsaQ  
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return n; 6Y?%G>$6  
} ]Hr:|2|.  
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} -5;Kyio  
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/* -}avH  
**SiteInfoBean.java  .>?h  
*/ aDEz|>q  
package NetFox; >SRUC  
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public class SiteInfoBean { .x\fPjB  
 +6paM  
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private String sSiteURL; //Site's URL XfY~q~f8  
private String sFilePath; //Saved File's Path EC9D.afy&  
private String sFileName; //Saved File's Name u\LG_/UJV1  
private int nSplitter; //Count of Splited Downloading File :sO^b*e /  
;VM',40  
}#0MJ6L  
public SiteInfoBean() 4HXqRFUD  
{//nSplitter的缺省值为5 |]=. ^  
//default value of nSplitter is 5 i T* !3  
this("","","",5); ]j.=zQP?'  
} j{}-zQ]n  
{ a2Y7\C/  
4cZig\mE;  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) w
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{ },1**_#<Br  
sSiteURL= sURL; vn oI.;H,  
sFilePath = sPath; dLA'cQId  
sFileName = sName; Qa*?iD  
this.nSplitter = nSpiltter; [f`^+,U  
@ qFE6!  
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} u=j|']hp#&  
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RSL%<  
public String getSSiteURL() n =SY66   
{ jC_7cAsl  
return sSiteURL; _`RzPIS^  
} %Xm3m0nsv{  
VrG4wLpLs  
8R!3}kx  
public void setSSiteURL(String value) !r=^aa(\  
{ /WIO@c  
sSiteURL = value; Z)iRc$;  
} r]!<iw  
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PT2b^PP  
public String getSFilePath() "= H.$ +  
{ E>_?9~8Mf  
return sFilePath; }qf9ra  
} t<`h(RczHI  
In
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public void setSFilePath(String value) 'vgO`  
{ 9`[#4'1Mik  
sFilePath = value; ,p(4OZz5,  
} sU7>q}!  
>;E[XG^  
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public String getSFileName() sOyWsXd+R'  
{ iz|mJUx  
return sFileName; w1zI"G~4/Q  
} |.bp  
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public void setSFileName(String value) 3F%Qq7v  
{ j s(E-d/  
sFileName = value; 9&'I?D&8  
} [\9
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Oto
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public int getNSplitter() ?nm:e.S+?  
{ !U02>X   
return nSplitter; 
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} cQ4TYr;?  
MSEBvZ-  
#=WDJT:  
public void setNSplitter(int nCount) 0m5Q;|mH  
{ (wJtEoB9^  
nSplitter = nCount; eO,  
} E(G=~>
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} Fa(}:Ug  
`I$qMw,@  
;qI5GQ {  
/* l+'1>T.I  
**Utility.java #vO3*-hs  
*/ o3H+.u
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package NetFox; Xco$ yF%  
Tb-`0^y&X1  
'e6W$?z  
public class Utility { C9-9cdW H  
UI~ENG  
0XlX7Sk+  
public Utility() "X']_:F1a  
{ Ow\9vf6H  
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~L(_q]  
} c ;3bX6RD*  
PN:8H>  
//线程睡眠 v9~Hl   
public static void sleep(int nSecond) [5%/{W,~m  
{ hp(n;(OR  
try{ m[^;H
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Thread.sleep(nSecond); =J8)Z'Jr  
} dE5DH~ldV  
catch(Exception e) ;{|a~e?Y  
{ @C=, >+D  
e.printStackTrace (); h3;Ij'  
} PMZdz>>T  
} ErC~,5dj;n  
Q}jbk9gM5  
//日志 f}4c#x  
public static void log(String sMsg) 'Rfvr7G/?  
{ V>P\yr?  
System.err.println(sMsg); Y6A]dk  
} Ja-D}|;  
@];#4O  
MW9B -x  
public static void log(int sMsg) tYfhKJzGC  
{ k?Jzy  
System.err.println(sMsg); hvBuQuk)  
} -b@E@uAX/  
} hE:P'O1  
;hs:wLVa"  
6\86E$f=h  
/* 2W pe( \(  
**TestMethod.java EpGe'S  
*/ [[D}
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package NetFox; P's<M  
)ymF:]QC  
`n-e.{O((  
public class TestMethod { u2<:mu[|P  
Oe9
{`~  
0jv9N6IM  
public TestMethod() z>j%-3_1  
{ ///xx/weblogic60b2_win.exe Y tG
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try{ G%YD2<V  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); @6*<Xs =  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 17D167\X  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }sy3M
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fileFetch.start(); sSG]I%oB3  
} :yT~.AK}>1  
catch(Exception e){e.printStackTrace ();} gb(\c:yg1R  
v03~=(  
tBBN62^X  
} (XqeX(s  
Cu;X{F'H  
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public static void main(String[] args) 5, Yk5?l<'  
{ v,>F0ofJ  
new TestMethod(); #Mbt%m  
} !^axO  
} #bu`W
!p}  
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