http断点续传简单实现（java)

/* YL&$cT]1  
**SiteFileFetch.java AqvRzi(Y  
*/ BD,JBu]  
package NetFox; Z;XR%n8  
import java.io.*; -B$oq8)n*  
import java.net.*; 'g#Ml`cm  
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public class SiteFileFetch extends Thread { 6}IOUWLB@  
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SiteInfoBean siteInfoBean = null; //文件信息Bean jDcE_55o  
long[] nStartPos; //开始位置 JGf6*D"O  
long[] nEndPos; //结束位置 7*OO k"9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 OnF+  
long nFileLength; //文件长度 @.T'  
boolean bFirst = true; //是否第一次取文件 J$&!Y[0  
boolean bStop = false; //停止标志 ]1%H.pF  
File tmpFile; //文件下载的临时信息 Ka2U@fK"  
DataOutputStream output; //输出到文件的输出流 `8\pihww  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） p{!aRB%  
public SiteFileFetch(SiteInfoBean bean) throws IOException NaG1j+LN  
{ ZP*Hx %U  
siteInfoBean = bean; v*QobI  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); z]Z>+|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5wRDH1z@{  
if(tmpFile.exists ()) l},*^Sn<5  
{ Q <^'v>~n  
bFirst = false; b.h~QyI/W  
read_nPos(); k$}XZ,Q  
}
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else ,Zzh.z::D  
{ X6!u(plVQ  
nStartPos = new long[bean.getNSplitter()]; *FR Eh@R
 
nEndPos = new long[bean.getNSplitter()]; }k duN0  
} C>N)~Ut  
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} nWbe=z&y8[  
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public void run() +uKlg#wqc  
{ :74^?  
//获得文件长度 `f*
?|)  
//分割文件 2y#4rl1Utx  
//实例FileSplitterFetch C#p$YQf  
//启动FileSplitterFetch线程 9Q^>.^~^  
//等待子线程返回 Ne@Iv)g?  
try{ v/8K?$"q  
if(bFirst) tn6\0_5n  
{ kxhvy,t  
nFileLength = getFileSize(); 0^]E-Zf  
if(nFileLength == -1)  ,L\OhT  
{ 7&:gvhw  
System.err.println("File Length is not known!"); JE9|;A  
} vC$[Zm  
else if(nFileLength == -2) QZ"Lh  
{ s8{3~Hv  
System.err.println("File is not access!"); -#Yg B5  
} 9O?.0L  
else /^DDU!=(<  
{ {]]nQ  
for(int i=0;i<nStartPos.length;i++) M=x/PrY"R  
{ pJVzT,poh  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); :"3WC
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} Bg"b,&/^u  
for(int i=0;i<nEndPos.length-1;i++) @YU}0&  
{ 4kT|/bp  
nEndPos = nStartPos[i+1]; 2hw3+o6  
} =YB3^Z  
nEndPos[nEndPos.length-1] = nFileLength; BGodrb1  
} wP6~HiC  
} +0.$w  
bh6Mh<+  
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//启动子线程 Up*p*(d3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; hrNri$  
for(int i=0;i<nStartPos.length;i++) >UE_FC*u  
{ EW0H"YIC  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _wCp.[3?t  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ZJ 8~f  
nStartPos,nEndPos,i); W.-[ceM  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); X"y rA;,o  
fileSplitterFetch.start(); ,@khV  
} ,@/b7BVv  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `U#*O+S-^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); PGP9-M  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "T<Q#^m  
nEndPos = " + nFileLength); |5Mhrb4.  
// fileSplitterFetch[nPos.length-1].start(); uz&CUvos  
R6h(mPYA  
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//等待子线程结束 giyKEnP  
//int count = 0; +Ys<V  
//是否结束while循环 l-XiQ#-{  
boolean breakWhile = false; ]V<[W,*(5  
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while(!bStop) {|^9y]VFu  
{ Um4 }`  
write_nPos(); I6M 7xn  
Utility.sleep(500); GW ?.b_6*  
breakWhile = true; :tedtV~  
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for(int i=0;i<nStartPos.length;i++) TC
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{ {K09U^JU  
if(!fileSplitterFetch.bDownOver) @7"xDgA  
{ "k)( ,  
breakWhile = false; zM|d9TS  
break; tU}CRh  
} ;jfjRcU  
} 0X~   
if(breakWhile) T3@wNAAU  
break; $`i$/FE  
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1wW8D>f]K  
//count++; UkG|5P`  
//if(count>4) bVQLj}%   
// siteStop(); Lf3Ri/@ p  
} [~W"$sT  
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System.err.println("文件下载结束！"); R^1sbmwk  
} [0lCb"  
catch(Exception e){e.printStackTrace ();} Z WL/AC  
} -=&
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G':mc{{  
//获得文件长度 f#ID:Ap3  
public long getFileSize() IU{~{(
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{ T@U_;v|rf  
int nFileLength = -1; x4CrWm  
try{ J*-m!0 5  
URL url = new URL(siteInfoBean.getSSiteURL()); L oe!@c  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o*_[3{FU  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^W eE%"  
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int responseCode=httpConnection.getResponseCode(); f+}?$'  
if(responseCode>=400) \tye:!a?;@  
{ _'ltz!~  
processErrorCode(responseCode); pZ/x,b#.  
return -2; //-2 represent access is error 8v8?D8\=|  
} 5,:>.LRA  
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b
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String sHeader; RgHPYf{  
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for(int i=1;;i++) _"&b%!  
{ y"#o9"&>&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); %Nwap~=H;  
//Utility.log(in.readLine()); S)iv k x  
sHeader=httpConnection.getHeaderFieldKey(i); 3Nd&*QSV  
if(sHeader!=null) )-xx$0mL-  
{ R^iF^IB  
if(sHeader.equals("Content-Length")) <ap%+(!I  
{ H1yl88K  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); mQ;b'0&  
break; ZF_*h`B  
} P
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} I5mnV
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else >2x[ub%$L  
break; :XxsDD  
} BKPXXR  
} F-R4S^eV  
catch(IOException e){e.printStackTrace ();} ZN~:^,PO/  
catch(Exception e){e.printStackTrace ();} D.kLx@Z  
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Utility.log(nFileLength); %E}f7GT4  
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return nFileLength; y))d[1E  
} !o+#T==p  
%"r3{Hs  

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//保存下载信息（文件指针位置） ?x7zYE,6  
private void write_nPos() &W`."  
{ gXZC%S  
try{ dT4?8:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); W=|sy-N{2  
output.writeInt(nStartPos.length); x9bfH1  
for(int i=0;i<nStartPos.length;i++) St7ZyN1  
{ $ jWe!]ASU  
// output.writeLong(nPos); 8)\TdtBf9  
output.writeLong(fileSplitterFetch.nStartPos); 7m~.V[l
1  
output.writeLong(fileSplitterFetch.nEndPos); \XFF(  
} +)k%jIi!  
output.close(); KC9_H>  
} %JeT,{  
catch(IOException e){e.printStackTrace ();} ekND>Qjj  
catch(Exception e){e.printStackTrace ();} J.W0F#?  
} m/Ou$  
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//读取保存的下载信息（文件指针位置） i2j_=X-  
private void read_nPos() HJ?p,V q5_  
{ -f@~{rK.L  
try{ v^1_'PAXu  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); k%YvJXL  
int nCount = input.readInt(); ShbW[*5  
nStartPos = new long[nCount]; `qn
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nEndPos = new long[nCount]; Clr~:2g\  
for(int i=0;i<nStartPos.length;i++) _LU]5$\
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{ =&jLwy  
nStartPos = input.readLong(); o
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nEndPos = input.readLong(); L}5nq@Uu)  
} .xo#rt9_"=  
input.close(); Y> ElE-  
} !LB#K?I  
catch(IOException e){e.printStackTrace ();} Opx"'HC@G  
catch(Exception e){e.printStackTrace ();} OPOL-2<wiy  
} bHZXMUewC  
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.Y|5i^i9{  
private void processErrorCode(int nErrorCode) m<qPj"g~L  
{ {_T?0L  
System.err.println("Error Code : " + nErrorCode); C ioM!D  
} 6..G/,T
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gg $/  
//停止文件下载 @'>h P  
public void siteStop() ^h #0e:7<  
{ ncZ5r0  
bStop = true; Q
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for(int i=0;i<nStartPos.length;i++) HjCcfOej  
fileSplitterFetch.splitterStop(); {ZQ|Ydpk  
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} +)YU/41W  
} tk=~b}8  
//负责部分文件的抓取 Af y\:&j  
**FileSplitterFetch.java
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*/ n1n->l*HGP  
package NetFox; ?=$=c8xw  
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import java.io.*; ip.aM#  
import java.net.*; ,xmL[Yk,  
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public class FileSplitterFetch extends Thread { kq+`.  
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String sURL; //File URL -aj)
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long nStartPos; //File Snippet Start Position v:.`~h/b  
long nEndPos; //File Snippet End Position q8 jI y@  
int nThreadID; //Thread's ID Ew
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boolean bDownOver = false; //Downing is over jiAKV0lX W  
boolean bStop = false; //Stop identical 3hUU$|^4gm  
FileAccessI fileAccessI = null; //File Access interface ?mM6[\DFoT  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException yex4A)n9"'  
{ #\DKU@|h  
this.sURL = sURL; [&_c.ti  
this.nStartPos = nStart; slPLc  
this.nEndPos = nEnd; o]gS=iLp  
nThreadID = id; tZ4Zj`x|^  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 78o>UWA:  
} y*6-
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22`N(_  
public void run() \~ACWF7l  
{ 83~9Xb=!\  
while(nStartPos < nEndPos && !bStop) :>G3N+A)  
{ >S]_{pb  
2p6`@8*34  
*U{E[<k{  
try{ 7E4Xvg
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URL url = new URL(sURL); X.YMb .\<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); L~Hgf/%5  
httpConnection.setRequestProperty("User-Agent","NetFox"); kuEB  
String sProperty = "bytes="+nStartPos+"-"; f*uD9l%/  
httpConnection.setRequestProperty("RANGE",sProperty); XwerQwO=  
Utility.log(sProperty); )U$]J*LI  
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InputStream input = httpConnection.getInputStream(); uoX] #<1J  
//logResponseHead(httpConnection); +WGL`RP  
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byte[] b = new byte[1024]; +[2X@J  
int nRead; rEWPVT  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) OI0tgkG  
{ W5#5RK"uX  
nStartPos += fileAccessI.write(b,0,nRead); ga#Yd}G^~3  
//if(nThreadID == 1) O7KR~d  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c"<bq}L7S  
} N=?! ~n9Q-  
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Utility.log("Thread " + nThreadID + " is over!"); >WKlR` J%  
bDownOver = true; (l~3~n  
//nPos = fileAccessI.write (b,0,nRead); ;:0gN|+  
} slV7,4S&!  
catch(Exception e){e.printStackTrace ();} y%9Q]7&=  
} qrq9NPf  
} P2Or|_z  
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//打印回应的头信息 r]0UF0#  
public void logResponseHead(HttpURLConnection con) [u=DAk?8  
{ K9
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for(int i=1;;i++) TAXl73j_CY  
{ ~582'-=+  
String header=con.getHeaderFieldKey(i); pPezy:  
if(header!=null) l}Fa-9_'  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); m4@f&6x  
Utility.log(header+" : "+con.getHeaderField(header)); p| #gn<z}  
else WecJ^{g>r{  
break; *C0gpEf9S  
} CYxrKW l:'  
} SdI/  
N]p|c3D  
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public void splitterStop() q|8p4X}/]  
{ /_,} o7@t~  
bStop = true; _z3Hl?qk=  
} te+5@k#t  
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} {]a
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/* rCmxv7" a}  
**FileAccess.java @c8s<9I]  
*//文件访问(定位，写) !Qg%d&q.Sx  
package NetFox; Q9~UL^bF  
import java.io.*; JqDj)}fzX  
K7x,>  
7 %P?3  
public class FileAccessI implements Serializable{ ]/d4o  
<?TJ-  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 &<u pjb  
RandomAccessFile oSavedFile; $j~oB:3n7  
long nPos; _n3Jf<Y  
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l7]$Wc[  
public FileAccessI() throws IOException wmNc)P4  
{ Wu 71q=  
this("",0); biFN]D  
} GM/3*S$c  
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public FileAccessI(String sName,long nPos) throws IOException S*H :/Ip  
{ bW`@9 =E  
oSavedFile = new RandomAccessFile(sName,"rw"); [xXml On!  
this.nPos = nPos; 6g ,U+~  
oSavedFile.seek(nPos); by {G{M`X  
} ,{C(<1  
GXEOgf#i  
/WDz;,X  
public synchronized int write(byte[] b,int nStart,int nLen) cZRLYOC  
{ Y[Gw<1F_  
int n = -1; RRD\V3C84  
try{ ^"w.v' sL  
oSavedFile.write(b,nStart,nLen); ;z9(  
n = nLen; NVnKgGlHgd  
} Bx&.Tj  
catch(IOException e) J3sO%4sYR  
{ k3m|I*_\L  
e.printStackTrace (); Q<L.!%vu}  
} ,EgIH%*g  
{-rK:*yP'u  
-=E/_c;  
return n; ?l_>rSly5  
} mu1oD;lQ  
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} vf@d(g  
r +] J {k  
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/* (n-8p6x(  
**SiteInfoBean.java IbpE@C  
*/ N(?yOB4gt  
package NetFox; xG_ ;F  
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public class SiteInfoBean { `8F%bc54iw  
ZkYc9!anY  
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private String sSiteURL; //Site's URL {uO8VL5+Qx  
private String sFilePath; //Saved File's Path 9p!V?cH#8  
private String sFileName; //Saved File's Name n=RAE^[
M  
private int nSplitter; //Count of Splited Downloading File k=[!{I  
-[#Mx}%  
vd-`?/,||  
public SiteInfoBean() k@5,6s:  
{//nSplitter的缺省值为5 I}Z[F,}*J  
//default value of nSplitter is 5 -A9 !Y{Z  
this("","","",5); Y#
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} ,{c9Lv%@J  
#VC^><)3  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) RR:m<9l  
{ J+&AtGq]u  
sSiteURL= sURL; J p .wg  
sFilePath = sPath; CF^7 {g(y_  
sFileName = sName; -8tWc]c |4  
this.nSplitter = nSpiltter; q*A2>0O  
%^"Tz,f  
0$,Ag;"^?  
} `QR2!W70o3  
8Es]WR5 ^  
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public String getSSiteURL() 0+8ThZ?
n  
{ dv%gmUUf}k  
return sSiteURL; j:|60hDz^  
} 'oTcx Jx  
 | qHWM  
U:MkA(S%c  
public void setSSiteURL(String value) <_ */  
{ _\"P<+!  
sSiteURL = value; N{/q p
 
} @DkPJla&  
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public String getSFilePath()
;ijJ%/  
{ e=Kv[R'(M  
return sFilePath; c6s(f  
} 5S$HDO&  
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public void setSFilePath(String value) GU'5`Yzd9  
{ f\~e&`PV  
sFilePath = value; v5wI?HE  
} @D"#B@j  
q)
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*8/Q_w  
public String getSFileName() 2{p`"xX  
{ p/lMv\`5  
return sFileName; jXi
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} ynM{hN.+H  
o^&; `XOd  
N,'JQch},8  
public void setSFileName(String value) I2j;9Qcz  
{ "MC&!AMv  
sFileName = value; h%+8}uywZ  
}  R76'1o  
<$Uj ~jN  
:`3b|u=KZ  
public int getNSplitter() }jiqUBn%  
{ 9z'</tJ`  
return nSplitter; lbg6n:@  
} 7@EYF  
Yc?taL)  
,l; &Tb=k  
public void setNSplitter(int nCount) EemKYcE@Nr  
{ %/etoK  
nSplitter = nCount; |,dMF2ADc  
} tt J,rM  
} G:WMocyXI'  
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/* Oku4EJFJ  
**Utility.java //ZB B,[@  
*/ GeHDc[7  
package NetFox; >+vWtO2  
:1Fm~'  
B"KsYB79t  
public class Utility { Q=PaTh   
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public Utility() (= !_5l  
{ XZ|"7as  
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} [b#jw,7  
0Ba
L!^>  
//线程睡眠 j{U-=[$'  
public static void sleep(int nSecond) 'R]Z9h  
{ M5ZWcD.1  
try{ q`$QroZT"  
Thread.sleep(nSecond); xo@N~
 
} %m+MEh"b5  
catch(Exception e) m\Tq0cT$  
{ $d8A_CUU  
e.printStackTrace (); n;Iey[7_E`  
} ['s_qCA[  
} mH{cGu?  
lf|^^2'*2<  
//日志 uhc0,V;S  
public static void log(String sMsg) G=nFs)z  
{ M\v4{\2l0  
System.err.println(sMsg); /$eEj  
} (6h7'r $  
.k*2T<p$rC  
o~4n8  
public static void log(int sMsg) c(Ha"tBJ  
{ rM=Hd/ki5  
System.err.println(sMsg); {eZj[*P  
} #[KwR\b{:+  
} ok6e=c '  
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8dA
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/* $s]@%6f  
**TestMethod.java iMA)(ZS  
*/ %BG5[XQ7  
package NetFox; _-!
6@^+  
CIaabn  
6wu/6DO   
public class TestMethod { ]@8=e'V  
"V^jAPDXb  
%[Ds-my2  
public TestMethod() ~IqT>  
{ ///xx/weblogic60b2_win.exe |Q I3H]T7  
try{  +;
!w;t  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); WX=+\`NyJ(  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); P)\f\yb  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3\WES!  
fileFetch.start(); F 5JgR-P  
} f:UN~z'yr  
catch(Exception e){e.printStackTrace ();} @2$8o]et  
}`M6+.z3F  
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} <
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<bjy<98LT  
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public static void main(String[] args) Q`s(T  
{ * ;M?R?+  
new TestMethod(); *ap#*}r!Nk  
} [`b{eLCFX]  
} VuBp$H(U  
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