http断点续传简单实现（java)

/* 2 :4o`o  
**SiteFileFetch.java =axuLP))  
*/ 8(ot<3(D  
package NetFox; k. NJ+  
import java.io.*; .Y0O.  
import java.net.*; va:<W H  
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public class SiteFileFetch extends Thread { (hBph+  
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SiteInfoBean siteInfoBean = null; //文件信息Bean }[=)sb_  
long[] nStartPos; //开始位置 '1rGsfp6In  
long[] nEndPos; //结束位置 1G6 \}El95  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +w7U7" xQ  
long nFileLength; //文件长度 l^^Z}3^Rk  
boolean bFirst = true; //是否第一次取文件 +\*b?x  
boolean bStop = false; //停止标志 4TI`   
File tmpFile; //文件下载的临时信息 ff7#LeB9  
DataOutputStream output; //输出到文件的输出流 !
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） PhPe7^  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?6\N&MTF  
{ &Z3%UOY  
siteInfoBean = bean; +p`BoF9~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); +V(^"Z~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Ir-QD!!<  
if(tmpFile.exists ()) F3K<-JK+  
{ MkHkM  
bFirst = false; -L4G)%L\  
read_nPos(); Lyf5Yf([-  
} T*gG <8  
else OSfT\8YA  
{ 7_P33l8y  
nStartPos = new long[bean.getNSplitter()]; .jg@UAK  
nEndPos = new long[bean.getNSplitter()]; G'u[0>  
} }K@m4`T  
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} XI|k,Ko<  
!*L)v  

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public void run() S-}c_zbl;  
{ sp:4b$zX  
//获得文件长度 I]i( B+D  
//分割文件 |O6/p7+.  
//实例FileSplitterFetch |OAM;@jH  
//启动FileSplitterFetch线程 %gs?~Xl)]  
//等待子线程返回 ~;]kqYIJ  
try{ k7Qs#L  
if(bFirst) NiWAJ]Z  
{ 
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nFileLength = getFileSize(); @MVul_@6  
if(nFileLength == -1) NJE*/_S  
{ (CRx'R  
System.err.println("File Length is not known!"); W6}>iB  
} akNqSZwj  
else if(nFileLength == -2) LEeA ,Y  
{ Ha|}Oj  
System.err.println("File is not access!"); 1KrJS(.  
} vpf.0!zh  
else WA,D=)GP  
{ FG[rH]  
for(int i=0;i<nStartPos.length;i++) 8Th,C{  
{ jc)7FE  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `_1~[t  
} V4NQcy? H  
for(int i=0;i<nEndPos.length-1;i++) B~ i  
{ aQ$sn<-l  
nEndPos = nStartPos[i+1]; hHmm(~5gR  
} "FA.T7G  
nEndPos[nEndPos.length-1] = nFileLength; d1\nMm}v  
} p*,T~(A6  
} bY.VNA  
~a[/l  
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//启动子线程 O+|C<;K  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; / @"{u0  
for(int i=0;i<nStartPos.length;i++) AK,'KO%{=  
{ 5]LWWjT  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _3@5@1[s  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), YwET.(oo  
nStartPos,nEndPos,i); V=*^C+6s  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }}$@Tij19[  
fileSplitterFetch.start(); {CI4AT!?W  
} j;y~vX b  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;j/$%lC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); c?HUW  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5[SwF&zZ  
nEndPos = " + nFileLength); I:iMRvp  
// fileSplitterFetch[nPos.length-1].start(); >*h+N? m  
a24 AmoWx  
[z2UfHpt~  
//等待子线程结束 9;U?_   
//int count = 0; MXcW &b  
//是否结束while循环 LZe)_9$  
boolean breakWhile = false; 2L1,;  
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i m;6$3  
while(!bStop) N7J?S~x  
{ K-C,n~-  
write_nPos(); N5=BjXSAg  
Utility.sleep(500); i>YQ<A1  
breakWhile = true; 5F~l;zT  
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>[|N%9\  
for(int i=0;i<nStartPos.length;i++) @!f4>iUy  
{ q%dG>!  
if(!fileSplitterFetch.bDownOver) ~\
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{ ,<tJ`,0X  
breakWhile = false; f<@!{y2Xe  
break; "g"a-{8  
} ~/`/r%1/J  
} }<A.zwB<i  
if(breakWhile) mg'q-G`\<  
break; ~#*C,4m  
. |T=T0^  
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//count++; `sCaGCp  
//if(count>4) 2P"9m  
// siteStop(); nL:&G'd  
} w_56y8Pd4  
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System.err.println("文件下载结束！"); M@A3+v%K  
}
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catch(Exception e){e.printStackTrace ();} {'O><4  
} QPx5`{nN  
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//获得文件长度  l!|c_  
public long getFileSize() .Ix3wR9  
{ s7 "xDDV  
int nFileLength = -1; \#9LwC"8;  
try{ sW]^YT>?  
URL url = new URL(siteInfoBean.getSSiteURL()); b0$)G-E/Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P9cx&Hk9  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,@ 8+%KqG  
o{s2T)2  
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int responseCode=httpConnection.getResponseCode(); jfxNV2[  
if(responseCode>=400) hC:'L9Y  
{ fc9;
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processErrorCode(responseCode); i<Vc~!pT  
return -2; //-2 represent access is error l$;"yVdks  
} AFz:%m  
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String sHeader; 7]h%?W!  
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%v0M~J}
+  
for(int i=1;;i++) DK4yAR,g  
{ r6m^~Wq!}  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &K9;GZS?  
//Utility.log(in.readLine()); Tru{8]uMH  
sHeader=httpConnection.getHeaderFieldKey(i); ]" 'yf;g  
if(sHeader!=null) Ww]$zd-bo  
{ g&Vhu8kNIA  
if(sHeader.equals("Content-Length")) <>] DcA  
{ 8MJJ w;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); v ccH(T  
break; ')uYI;h9  
} ,-pE/3|(  
} MKHnA|uQ](  
else @?,x3\N-  
break; 2@|`Ugjptl  
} nQF&^1n  
} 1V%tev9a  
catch(IOException e){e.printStackTrace ();} -+".ut:R  
catch(Exception e){e.printStackTrace ();} KYFKH+d>m  
wNf:_^|}  
ewMVUq*:  
Utility.log(nFileLength); clE9I<1v  
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return nFileLength; ;wv[';
J  
} 42Z:J 0  
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//保存下载信息（文件指针位置） x5lVb$!G  
private void write_nPos() m}]{Y'i]R  
{ N1t4o~  
try{ x93@[B*%  
output = new DataOutputStream(new FileOutputStream(tmpFile)); a"#t'\  
output.writeInt(nStartPos.length); $S6(V}yh  
for(int i=0;i<nStartPos.length;i++) S:xXD^n#H  
{ 0Wr<l%M)+  
// output.writeLong(nPos); y,D9O/VP  
output.writeLong(fileSplitterFetch.nStartPos); LO`0^r  
output.writeLong(fileSplitterFetch.nEndPos); PR{ubMn  
} &h5Vhzq(<  
output.close(); `G\ qGllX  
} *p{p.%Qs:  
catch(IOException e){e.printStackTrace ();} r_7%|T8  
catch(Exception e){e.printStackTrace ();} 
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} R`j"iC2  
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//读取保存的下载信息（文件指针位置） +ai3   
private void read_nPos() 1 iH@vd  
{ !yNU-/K  
try{ s< tG  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,:S#gN{U  
int nCount = input.readInt(); <J8c dB!e  
nStartPos = new long[nCount]; Q2fxsa[  
nEndPos = new long[nCount]; S>lP?2J  
for(int i=0;i<nStartPos.length;i++) @nH3nn  
{ Xu{y5N  
nStartPos = input.readLong(); m(f`=+lqI`  
nEndPos = input.readLong(); zw<<st Bp  
} xF_u:}7`  
input.close(); @]Q4K%1^"  
} VwR\"8r3  
catch(IOException e){e.printStackTrace ();} {4+/0\  
catch(Exception e){e.printStackTrace ();} IADSWzQ@  
} eF3NyL(A  
>?+Rtg|${  
;MfqI/B{  
private void processErrorCode(int nErrorCode) 4"
?`p;{Z  
{ AD   
System.err.println("Error Code : " + nErrorCode); '6D"QDZB  
} zC*FeqFL<  
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//停止文件下载 O_ #++G  
public void siteStop() TG=A]--_a  
{ ;adZ*'6u  
bStop = true; | .+P ;g  
for(int i=0;i<nStartPos.length;i++) 60{G 4b)  
fileSplitterFetch.splitterStop(); \O*ZW7?TJ  
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} F-kjv\  
} %)V=)l.j  
//负责部分文件的抓取 w/NT5  
**FileSplitterFetch.java sm##owI  
*/ !>(uhuTBF  
package NetFox; 'e:4  
X -1r$.
  
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import java.io.*; .*NPoW4Kv  
import java.net.*; J@_M%eN  
vU *: M8k  
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public class FileSplitterFetch extends Thread { +;+G+Tn  
) `{jPK*`  
/Ey%aA4v  
String sURL; //File URL {]Mw
uqn  
long nStartPos; //File Snippet Start Position `U0XvWPr[  
long nEndPos; //File Snippet End Position h]@'M1D%  
int nThreadID; //Thread's ID N+~ MS3  
boolean bDownOver = false; //Downing is over 
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boolean bStop = false; //Stop identical |HAbZd
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FileAccessI fileAccessI = null; //File Access interface o4: e1  
(tO4UI5!  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException M_0f{  
{ R?{_Q<17  
this.sURL = sURL; bV:<%l]  
this.nStartPos = nStart; @nqM
#  
this.nEndPos = nEnd; (x% 4*  
nThreadID = id; K1YxF  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "} :CM_  
} ['>ZC3?"h  
idHI)6!  
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public void run() Sv=e|!3f[k  
{ o(}%b8 K  
while(nStartPos < nEndPos && !bStop) Z|KDi `S  
{ zWPX  
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try{ w\[l4|g`  
URL url = new URL(sURL); lpPPI+|4N  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); z\FBN=54z  
httpConnection.setRequestProperty("User-Agent","NetFox"); eSIG+{;&  
String sProperty = "bytes="+nStartPos+"-"; z-3.%P2g  
httpConnection.setRequestProperty("RANGE",sProperty); tvno3"  
Utility.log(sProperty); ] 0L
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).HA#!SE  
[$K8y&\L  
InputStream input = httpConnection.getInputStream(); NHUJ:j@  
//logResponseHead(httpConnection); nN.Gn+Cl  
bGB$a0  
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byte[] b = new byte[1024]; *Dq ++  
int nRead; aZo}Ix:/  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) W'Ew!]Q3  
{ AJ}m2EH  
nStartPos += fileAccessI.write(b,0,nRead); tKyGD|g S  
//if(nThreadID == 1) L[:AUe  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f.j
<VKF}  
} ^6{op3R_  
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*[i49X&rd  
Utility.log("Thread " + nThreadID + " is over!"); L1+s0g>  
bDownOver = true; [So1`IA6  
//nPos = fileAccessI.write (b,0,nRead); I%:?f{\  
} #mJRL[V5^  
catch(Exception e){e.printStackTrace ();} nT01B1/<]  
} >Mh\jt\  
} 5|jY  
+qpG$#J0  
/? d)01  
//打印回应的头信息 K2Ro0  
public void logResponseHead(HttpURLConnection con) Is6}VLbB  
{ ) x+edYw  
for(int i=1;;i++) (#6Fg|f4Y  
{ V=fh;p  
String header=con.getHeaderFieldKey(i); `<~=6H  
if(header!=null) %MGt3)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Nw9:Gi  
Utility.log(header+" : "+con.getHeaderField(header)); yK&  
else `#W+pO  
break; s8's(*]  
} a_0I)' ?  
} T(Yp90'6  
y'b*Dk{  
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public void splitterStop() !U}2YM J  
{ D/"velV  
bStop = true; S"?fa)~  
} <@GO]vY  
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} S:i#|T."  
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k18v{)i~  
/* i5Sya]FN  
**FileAccess.java HnjA78%i  
*//文件访问(定位，写) ZI1]B944ni  
package NetFox; 2z#S
|$  
import java.io.*; DrioBb@  
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9M($_2,44  
public class FileAccessI implements Serializable{ 5rbb ,*  
+C~d;p  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 uJH[C>  
RandomAccessFile oSavedFile; 0,m]W)  
long nPos;
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*k8?$(  
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public FileAccessI() throws IOException >"=DN5w ,S  
{ JttDRN
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this("",0); !Tv3WQ@  
} 9)W &yi  
&V~l(1  
6YNL4HE?  
public FileAccessI(String sName,long nPos) throws IOException itirh"[  
{ 
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oSavedFile = new RandomAccessFile(sName,"rw"); %aw.o*@:  
this.nPos = nPos; 4c(Em+4  
oSavedFile.seek(nPos); `vOL3`P  
} &*7KQd  
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public synchronized int write(byte[] b,int nStart,int nLen) MaHP):~  
{ ^5
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int n = -1; w
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try{ Kd^.>T-
 
oSavedFile.write(b,nStart,nLen); s^eiymP  
n = nLen; kUS]g r~i  
} f4Y)GO<R]  
catch(IOException e) HLwMo&*rA  
{ Ws`ndR  
e.printStackTrace (); -c0ypz  
} 9>9EZ?4m  
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1,;X4/*  
return n; ; iia?f1  
} }}tbOD)t  
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} 9|}Pf_5]%[  
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/* \/Mx|7<  
**SiteInfoBean.java rjK`t_(=  
*/ f2;.He  
package NetFox; [TFJb+N
&  
[MFnS",7c  
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public class SiteInfoBean { W/ Q*NB  
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BtC*]WB"_'  
private String sSiteURL; //Site's URL ;cI*"-I:F  
private String sFilePath; //Saved File's Path @GFB{ ;=  
private String sFileName; //Saved File's Name (\{k-2t*^  
private int nSplitter; //Count of Splited Downloading File R^*baiXVI  
 @;bBc  
RTm/-6[N  
public SiteInfoBean() \uJRjw+  
{//nSplitter的缺省值为5 IQ I8v  
//default value of nSplitter is 5 R{H[< s+n  
this("","","",5); T^1 Z_|A  
} y'K2#Y~1e  
;ItH2Lw<&  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Mu?|<#s  
{ 8D*nU3O   
sSiteURL= sURL; E&P2E3P  
sFilePath = sPath; -d\sKc  
sFileName = sName; i3,IEN  
this.nSplitter = nSpiltter; =:^aBN#  
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} sE pI)9  
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public String getSSiteURL() R c+olJ^5  
{ C!VhVOy>d  
return sSiteURL; gc.L
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} ITn%  
J-v1"7[2GC  
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public void setSSiteURL(String value) \VNu35* J|  
{ 6O7s^d&K  
sSiteURL = value;
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} 6:ettdj  
,CfslhO{j  
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public String getSFilePath() Jb QK$[z"  
{ QqA=QTZ}  
return sFilePath; ~3F'X  
} h'y%TOob  
[.gk{> #  
9TW[;P2> )  
public void setSFilePath(String value) @+gr/Pul
^  
{ W[ l  
sFilePath = value; g#J`7n  
} 'hpOpIsHa  
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u 272)@R  
public String getSFileName() mmTpF]t ?`  
{ EeW ,-I  
return sFileName; ?jmP]MM  
} t'n@yX_  
:os8"  
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public void setSFileName(String value) Q|'f3\  
{ Er;/zxg9p  
sFileName = value; _~<sb,W  
} |P >"a`  
#e'>9T  
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public int getNSplitter() Bs"D<r&ro  
{ 5\Q Tm;  
return nSplitter; jIol`WX  
} daE.y_9y  
%K6veB{M  
GX>8B:]o|  
public void setNSplitter(int nCount) 6"&cQ>$xh  
{ Tagf7tw4  
nSplitter = nCount; {L-^J`> G  
} )DgXsT  
} y )QLR<wf  
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/* ^O07GYF  
**Utility.java HpnF,4A>  
*/ }y(t')=9  
package NetFox; -xn-Af!v  
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public class Utility { %U\,IO`g  
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cl& w/OJ#  
public Utility() \+ se%O  
{ x~e._k=  
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} }z`x-(V  
%e iV^>  
//线程睡眠 yXNr[7  
public static void sleep(int nSecond) VGS%U8;  
{ (xfc_h*xA  
try{ CIW4E  
Thread.sleep(nSecond); 8E%
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} \s=r[0tj!  
catch(Exception e) cYSn   
{ , $7-SN  
e.printStackTrace (); )N.3Q1g-  
} dxeiN#(XT  
} Kb;*"@LX  
8zK#./0\  
//日志 *!QmYH5r0  
public static void log(String sMsg) j7}mh  
{ iOiFkka  
System.err.println(sMsg); 6#z8 %kaX  
} SU0SsgFB  
!>48`o^  
}B0[S_mw  
public static void log(int sMsg) " MnWd BS  
{ UC`h o%OBF  
System.err.println(sMsg); &y? |$p\;/  
} ;[y( 14g  
} d"|_NG`vr  
Ej(BE@6>s  
)1At/
mr  
/* c=v016r\  
**TestMethod.java Oo|JIr7i  
*/ A7L;ims7  
package NetFox; j@xIa-{*  
8a6.77c  
rN1]UaT  
public class TestMethod { @X/ 1`Mp  
@b(@`yz.a  
AXbb-GK  
public TestMethod() +$C9@CZM9  
{ ///xx/weblogic60b2_win.exe pA8bFtt  
try{ m* 3ipI{h  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 'Xik2PaO  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Zh8\B)0unn  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "](Q2  
fileFetch.start(); l%+ &V^:  
} L2@:?WW[  
catch(Exception e){e.printStackTrace ();} QGN+f)  
Ou
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(BY 0b%^  
} ;Z*rY?v  
tav@a)  
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public static void main(String[] args) O _9r-Zt^  
{ >vD}gGBe  
new TestMethod(); j \rGU){  
} y A5h^I  
} %ddH4Q/p  
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