http断点续传简单实现（java)

/* ;W]\rft[  
**SiteFileFetch.java wi_

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*/ :g6n,p_#  
package NetFox; \]uV!)V5B  
import java.io.*; -TO\'^][X  
import java.net.*; ;"kaF!  
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public class SiteFileFetch extends Thread { NX[4PKJ0C  
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SiteInfoBean siteInfoBean = null; //文件信息Bean .iG&Lw\,  
long[] nStartPos; //开始位置 W$0^(FH[  
long[] nEndPos; //结束位置 c!#:E`  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Y}s@WJ  
long nFileLength; //文件长度 E&`Nh5JfC  
boolean bFirst = true; //是否第一次取文件 x79Ha,  
boolean bStop = false; //停止标志 eJ0?=u!x  
File tmpFile; //文件下载的临时信息 a5YIUVCv  
DataOutputStream output; //输出到文件的输出流 n]}W``=7  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） x3 >  
public SiteFileFetch(SiteInfoBean bean) throws IOException asHxL!  
{ q1?&Ev^  
siteInfoBean = bean; *v ?m6R=)h  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); X5LBEOG  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #|[ M?3  
if(tmpFile.exists ()) T 20&F  
{ ;&V s4  
bFirst = false; TaE~s  
read_nPos(); H@bf'guA|B  
} T*g:# ^4  
else Dre2
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{ i4JqT\q  
nStartPos = new long[bean.getNSplitter()]; eI45PMP  
nEndPos = new long[bean.getNSplitter()]; _{<seA  
} 1u3,'8F  
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} U_x)#,4  
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public void run() wLc4Dm*V  
{ yY?b.ty  
//获得文件长度 HK`I\,K  
//分割文件 '3zc|eJt&  
//实例FileSplitterFetch )nL`H^  
//启动FileSplitterFetch线程 >leU:7  
//等待子线程返回 [ ol9|sdu  
try{ 'AN>`\mR$  
if(bFirst) _SW3_8SuM.  
{ /1Ue?)g  
nFileLength = getFileSize(); k0Ol*L!p  
if(nFileLength == -1) DC{>TC[p1k  
{ ]a5 f2lE  
System.err.println("File Length is not known!"); lXcx@
#~  
} AGLscf.  
else if(nFileLength == -2) 'Ut7{rZ5  
{ |{CfWSB7~@  
System.err.println("File is not access!"); ggJO:$?$L  
} :Nofp&  
else 9eH$XYy
 
{ 15o9 .   
for(int i=0;i<nStartPos.length;i++) 'Lu__NfN  
{ |PC*=ykT3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); (Jz1vEEV  
} Na:w]r:y  
for(int i=0;i<nEndPos.length-1;i++) }GeSu|m(  
{ : |>Gc39`t  
nEndPos = nStartPos[i+1]; z11O F  
}
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nEndPos[nEndPos.length-1] = nFileLength; |`.([2  
} l<A|d{"]  
} D8$G`~hD  
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//启动子线程 gP;&e:/3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; r-Pkfy(  
for(int i=0;i<nStartPos.length;i++) ZzSz%z_sE  
{ Ft&]7dT{W  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ' ~8KSF*!p  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), H!$o$}A  
nStartPos,nEndPos,i); NuQdSj_>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  iKT[=c  
fileSplitterFetch.start(); E"5*Ei)^3  
} "thdPZ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), NfjE`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); FY#C.mL  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2+e}*&iQpp  
nEndPos = " + nFileLength); MB]<Dyj,  
// fileSplitterFetch[nPos.length-1].start(); EwvoQ$#jv  
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TA4!$7b$  
//等待子线程结束 ,^\2P$rT  
//int count = 0; De'_SD|=  
//是否结束while循环 7t0er'VC  
boolean breakWhile = false; ;EP:
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while(!bStop) 5Ou`z5S\k  
{ -#N.X_F  
write_nPos(); }E50>g  
Utility.sleep(500); ^f4s"T  
breakWhile = true; 6\q]rfQ  
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for(int i=0;i<nStartPos.length;i++) 0"28'  
{ ).`1+b  
if(!fileSplitterFetch.bDownOver) qKr8)}h  
{ d,B:kE0Y  
breakWhile = false; Bf~vA4  
break; KUlp"{a`,K  
} G}b]w~ML~  
} !Fd~~v  
if(breakWhile) RC7]'4o  
break; 3u*4o=4e  
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//count++; 3q\,$*D.  
//if(count>4) nxnv,AZG  
// siteStop(); =5~jx  
} \/zq7j  
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System.err.println("文件下载结束！"); mwHB(7YS,  
} FKDk+ojw  
catch(Exception e){e.printStackTrace ();} YNKHN2E8  
} Czs8!S  
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//获得文件长度 `yrB->|vG  
public long getFileSize() 3no%E03p  
{ [+T.at  
int nFileLength = -1; i&bA2p3+d  
try{ [9evz}X  
URL url = new URL(siteInfoBean.getSSiteURL()); qouhuH_WtJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); EE&K0<?T|:  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,8U&?8l  
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int responseCode=httpConnection.getResponseCode(); +Vb.lH[av  
if(responseCode>=400) Gp?a(-K5  
{ ?+@n3]`0  
processErrorCode(responseCode); fphv  
return -2; //-2 represent access is error e^6)Zz1\  
} +%
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String sHeader;  VA6}  
+\d56j+D  
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for(int i=1;;i++) sBj(Qd  
{ _mqL8ho  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 3`t#UY).F  
//Utility.log(in.readLine()); V#2+"(7h  
sHeader=httpConnection.getHeaderFieldKey(i); W <9T0sZ  
if(sHeader!=null) aL+ o /  
{ % L$bf#  
if(sHeader.equals("Content-Length")) _<n~n]%  
{ _C%3h5  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); -;s|  
break; '.IW.{;$  
} `uv2H$  
} QO<jI#  
else 2Q/x@aT,h  
break; K -nF lPm\  
} \tf<B\oa  
} {j.bC@hWw  
catch(IOException e){e.printStackTrace ();} cM(:xv  
catch(Exception e){e.printStackTrace ();} l: HTk4$0  
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Utility.log(nFileLength); |s7s6k)mm  
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return nFileLength; 27eooY1  
} ^n*)7K[  
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R/~p>apg8  
//保存下载信息（文件指针位置） y;35WtDVb  
private void write_nPos() Nyku4r0  
{ 7-bd9uVK  
try{ $SlIr<'*"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); H4WP~(__  
output.writeInt(nStartPos.length); tURu0`](  
for(int i=0;i<nStartPos.length;i++) u 1>2
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{ ]J1dt
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// output.writeLong(nPos); qzYwt]GNS  
output.writeLong(fileSplitterFetch.nStartPos); "3X2VFwo
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output.writeLong(fileSplitterFetch.nEndPos); ^h(ew1:  
} R6` WN  
output.close(); hE-h`'ha`  
} NH[kNi'  
catch(IOException e){e.printStackTrace ();} iw3FA4{(  
catch(Exception e){e.printStackTrace ();} ef8s<5"4  
} 4`4kfi
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,82S=N5V!  
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//读取保存的下载信息（文件指针位置） /Wi[OT14  
private void read_nPos() iN bIp"W  
{ D#_3^Kiawj  
try{ !{ y@od@T  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 4GkWRu1  
int nCount = input.readInt(); GSoX<*i  
nStartPos = new long[nCount]; 8v:T.o;<  
nEndPos = new long[nCount]; `LrHKb aP  
for(int i=0;i<nStartPos.length;i++) Y4J3-wK5  
{ 1$xNUsD2  
nStartPos = input.readLong(); >@U*~Nz  
nEndPos = input.readLong(); qrb[-|ie&  
} iW)8j 8  
input.close(); Q)~aiI0  
} x) ,eI'mf  
catch(IOException e){e.printStackTrace ();} AuvkecuIh  
catch(Exception e){e.printStackTrace ();} ayn)5q/z  
} ^%d\qd`   
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private void processErrorCode(int nErrorCode) h){0rX@:&  
{ ?qmRbDI  
System.err.println("Error Code : " + nErrorCode); =J18eH!]  
} '*Z1tDFS  
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//停止文件下载 J!AgBF N4  
public void siteStop() TtJH7  
{ TYy?KG>:'  
bStop = true; +vw\y  
for(int i=0;i<nStartPos.length;i++) .8 2P(}h  
fileSplitterFetch.splitterStop(); |hKDvH  
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} r7RIRg_  
} 8^kGS-+^  
//负责部分文件的抓取 /,BD#|  
**FileSplitterFetch.java L 8c0lx}Nn  
*/ mu\6z_e  
package NetFox; kVuUjP6(c  
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import java.io.*; Ja|5 @  
import java.net.*; |O{m2Fi  
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public class FileSplitterFetch extends Thread { !`M,XSp(  
*2ZjE!A  
MH =%-S   
String sURL; //File URL 1m'k|Ka  
long nStartPos; //File Snippet Start Position GiJ *Wp  
long nEndPos; //File Snippet End Position nB_?ckj,  
int nThreadID; //Thread's ID *zaQx+L  
boolean bDownOver = false; //Downing is over ?3/qz(bM  
boolean bStop = false; //Stop identical R]JT&p|w.1  
FileAccessI fileAccessI = null; //File Access interface l?\jB\,  
'I`&Yo~c9  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException DKH-Q(M56  
{ 0^v`T%|fTX  
this.sURL = sURL; ,xw#NG6  
this.nStartPos = nStart; Mhm@R@  
this.nEndPos = nEnd; ;RH;OE,A  
nThreadID = id; &U{#Kt5q  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *~2,/D  
} 5v[*:0p'  
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public void run() '%>=ZhO  
{ #./fY;:cj  
while(nStartPos < nEndPos && !bStop) {WJm  
{ M "ui0 ac  
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#^#PP
O  
try{ Y`KqEjsC*  
URL url = new URL(sURL); s'3 s^Dd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); pk>^?MO  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,1hxw<sNR  
String sProperty = "bytes="+nStartPos+"-"; )"qa kT  
httpConnection.setRequestProperty("RANGE",sProperty); [.K1iZyTi  
Utility.log(sProperty); NxfOF  
8aZ=?_gvT  
} FE>|1  
InputStream input = httpConnection.getInputStream(); 9
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//logResponseHead(httpConnection); GL&y@6  
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byte[] b = new byte[1024]; PoNi"Pv  
int nRead; S2E8Gq9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) rDl*d`He!  
{ XWnVgY s  
nStartPos += fileAccessI.write(b,0,nRead); A4Rug\p]  
//if(nThreadID == 1) ?llXd4  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r`$OO,W  
} vjLJinJ/  
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Utility.log("Thread " + nThreadID + " is over!");  vx\r!]  
bDownOver = true; ) g0%{dfJ  
//nPos = fileAccessI.write (b,0,nRead); oVnvO iAc  
} )S3\,S-.  
catch(Exception e){e.printStackTrace ();} ; a/X<  
} hZdoc<  
} Y1L[;)Hn  
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//打印回应的头信息 R$v[!A+:'  
public void logResponseHead(HttpURLConnection con) 2iHUZzz\  
{ v>:Ur}u!D  
for(int i=1;;i++) ~Io7]  
{ *lYVY)L  
String header=con.getHeaderFieldKey(i); 
^pxX]G]  
if(header!=null) v5/~-uRL%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~Uj=^leYO  
Utility.log(header+" : "+con.getHeaderField(header)); d+<G1w&z  
else bNm#tmSt  
break; UG'Q]S#!  
} r~E=4oB7  
} \?w2a$?6w  
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public void splitterStop() >/g#lS 5  
{ Hek*R?M|  
bStop = true; d.3E[AJa(  
} Mh~q//  
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} ^b/ Z)3  
|_LU~7./  
//*fSF
 
/* wZG\>9~  
**FileAccess.java X]'{(?Ch  
*//文件访问(定位，写) IW>T}@ |  
package NetFox; +GG9^:<yr  
import java.io.*; *Tas`WA  
4^:\0UF  

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public class FileAccessI implements Serializable{ 7[w,:9& }  
mi ik%7>W  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 d^Inb!%w  
RandomAccessFile oSavedFile; e63uLWDT  
long nPos; 
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public FileAccessI() throws IOException ?u-|>N>  
{ .)RzT9sg  
this("",0); a,xycX:U  
} kr+D,h01  
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public FileAccessI(String sName,long nPos) throws IOException V\{clJ\U  
{ 4S5,w(6N  
oSavedFile = new RandomAccessFile(sName,"rw"); XJ;D=~  
this.nPos = nPos; E'G4Y-  
oSavedFile.seek(nPos); 4\y/'`xm)6  
} K$>%e36Cc  
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H!?c\7adX  
public synchronized int write(byte[] b,int nStart,int nLen) 0":ib0=  
{ ?$vCW|f  
int n = -1; mZk]l5Lc  
try{ I2TaT(e\  
oSavedFile.write(b,nStart,nLen); $AfM>+GQ`n  
n = nLen; 1|RANy  
} { WIJC',Y  
catch(IOException e) yGWxpzmRS  
{ kB3H="3[[  
e.printStackTrace (); `Zf^E >)  
} U[SaY0Z  
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return n; 61.Brp.eP  
} 6`O.!
|)  
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} 0KYEb%44  
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/* ,u!*2cWN  
**SiteInfoBean.java h?rp|uPQ  
*/ m5L-67[sB  
package NetFox; .P;*Dws  
6qRx0"qB  
?!9)q.bW  
public class SiteInfoBean { U@gn;@\  
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private String sSiteURL; //Site's URL _&N2'hG=sn  
private String sFilePath; //Saved File's Path N"8_S0=pw  
private String sFileName; //Saved File's Name )>.&N[
v  
private int nSplitter; //Count of Splited Downloading File n1~o1  
{XNREjhm  
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public SiteInfoBean() fG}tMSI  
{//nSplitter的缺省值为5 |(pRaiJ  
//default value of nSplitter is 5 X*&[u7No  
this("","","",5); $]{k+Jf  
} P/c&@_b  
/4c\K-Z;  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) X}tVmO?  
{ <<(wa j  
sSiteURL= sURL; R#2t)y  
sFilePath = sPath; ZT,B(#m  
sFileName = sName; @\0Eu212  
this.nSplitter = nSpiltter; R($KSui  
5"HVBfFk  
2Tfz=7h$  
} <1FC%f/  
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K@#(*."  
public String getSSiteURL() twP,cyR  
{ zoOaVV&1  
return sSiteURL; hJDi7P  
} q0$ !y!~  
pV20oSJNt  
I 6<*X  
public void setSSiteURL(String value) ;k7xMZs  
{ 3T"j)R_=l  
sSiteURL = value; FP;Ccl"s  
} $4tWI O  
h<Ft_#|o[  
D&}3$ 7>  
public String getSFilePath() UG)8D5  
{ JS*m65e  
return sFilePath; VwOW=4`6  
} dZi(&s  
HRi
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DS  
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public void setSFilePath(String value) ag*mG*Z  
{ :cq9f2)  
sFilePath = value; 0TGLM#{  
} j:E<p_T  
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public String getSFileName() s<oNE)xe  
{ NR -!VJQ  
return sFileName; y($%;l   
} t%'Z<DmG+  
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public void setSFileName(String value) e XfZ5(na  
{ 7VMvF/ap]u  
sFileName = value; u86"Y^d#  
} xKQ+{"?-^g  
{_S}H1,  
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public int getNSplitter() =dII- L=`  
{ )yTm.F  
return nSplitter; qEpi]=|  
} 1jc, Y.mP  
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public void setNSplitter(int nCount) f. FYR|%tq  
{ SE),":aY  
nSplitter = nCount; ``OD.aY^s  
} 'bo~%WA]n  
} XLL/4)  
|!"2fI  
Iz ;G*W18  
/* Yc,7tUz#  
**Utility.java 'g$(QvGF9  
*/ 4\6N~P86  
package NetFox; iVd.f A  

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public class Utility { rk7QZVE  
R,|d`)T  
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public Utility() r8,romE$  
{ nWMmna.5  
x\J#]d.  
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} LE*h9((  
aj?a^}X  
//线程睡眠 'JNElXqrv  
public static void sleep(int nSecond) {W]=~*w  
{ ]79:yMD~ba  
try{ ox%9Ph  
Thread.sleep(nSecond); N_pJk2E  
} 1qf!DMcdZ  
catch(Exception e) DSt]{fl`P  
{ xj[(P$,P  
e.printStackTrace (); (y M^  
} O9g{+e`  
} :%sXO  
FI
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//日志 TpHfS]W-P  
public static void log(String sMsg) @DZB9DDR  
{ CT1ja.\;  
System.err.println(sMsg); 2At
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} LrATSq@  
vq!_^F<  
XK: 9r{r{  
public static void log(int sMsg) M?[h0{^K  
{ <
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System.err.println(sMsg); Tp0b
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} 5cEcTJL[C  
} Y_]De3:V0B  
1!.(4gV  
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/* +e-G,%>9  
**TestMethod.java JqMDqPIQ  
*/ %zSuK8kxV  
package NetFox; Vo7dAHHL  
%s&ChM?8F  
>-O/U5<!  
public class TestMethod { ]ix!tb.Q  
@"o@}9=d  
lRveHB&V  
public TestMethod() /__PSK  
{ ///xx/weblogic60b2_win.exe HgBGV0  
try{ MdXchO-Lyc  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); BSkDpr1C
 
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5*0y7K/D  
SiteFileFetch fileFetch = new SiteFileFetch(bean); XEdzpkB  
fileFetch.start(); #rY sj-2  
} HU9Sl*/  
catch(Exception e){e.printStackTrace ();} 4[BG#  
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} iC*F
  
#^4,GLIM  
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public static void main(String[] args) P)uDLFp]  
{ 8o/}}=m$  
new TestMethod(); 5r?m&28X  
} !xwG%{_  
} ]XTu+T.aT  
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