http断点续传简单实现（java)

/* ZaXK=%
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**SiteFileFetch.java B\Rq0N]' M  
*/ |Q.?<T:wt=  
package NetFox; t2tH%%Rs  
import java.io.*; &k : |  
import java.net.*; 1`B5pcuI  
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public class SiteFileFetch extends Thread { bpKMQrwd  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ]<W1edr  
long[] nStartPos; //开始位置 X-~Q  
long[] nEndPos; //结束位置 ^_)CQ%W?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ,|xG2G6  
long nFileLength; //文件长度 jVk|(  
boolean bFirst = true; //是否第一次取文件 od?Q&'A  
boolean bStop = false; //停止标志 r`wL_>"{n  
File tmpFile; //文件下载的临时信息 N|7<*\o  
DataOutputStream output; //输出到文件的输出流 J>XaQfzwU  
q w|M~vdm  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） iT9cw`A^%  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?CL1^N%  
{ _lyP7$[: c  
siteInfoBean = bean; *%uv7G@%N  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); fB;'U  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }wj*^>*  
if(tmpFile.exists ()) mj5A*%"W  
{ R!}B^DVt  
bFirst = false; P{QRmEE  
read_nPos(); AVNB)K"  
} pN4!*7M  
else ]p+t>'s  
{ 6TPcG dZ  
nStartPos = new long[bean.getNSplitter()]; 8*6J\FE<p  
nEndPos = new long[bean.getNSplitter()]; A(;J  
} Qpf BM  
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} gY*Cl1 Iz  
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public void run() !jYV,:'  
{ ,,BNUj/:  
//获得文件长度 0Xk;X1Xl  
//分割文件 pok,`yW\  
//实例FileSplitterFetch }})4S
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//启动FileSplitterFetch线程 |nU:  
//等待子线程返回 y<3v/,Y  
try{ mn0QVkb}lc  
if(bFirst) JBb}{fo~  
{ '*-X
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nFileLength = getFileSize(); dVe3h.
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if(nFileLength == -1) 8Bhot,u'T  
{ Z][?'^`^!  
System.err.println("File Length is not known!"); _;LH
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} R+!2 j  
else if(nFileLength == -2) ]V.9jlXF  
{ nV']^3b  
System.err.println("File is not access!"); nW|[poQK  
} 1Rp|*>  
else mjs*Z{_F^  
{ ' P-K}Y  
for(int i=0;i<nStartPos.length;i++) QW6k!ms$  
{ 8yztVdh  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); _DJ0MR~3  
} kAy.o  
for(int i=0;i<nEndPos.length-1;i++) ?{{E/J:%  
{ =WDf [?ED  
nEndPos = nStartPos[i+1]; @X\nY</E#M  
} 8oA6'%.e  
nEndPos[nEndPos.length-1] = nFileLength; _MMz x2}  
} Y71b Lg  
}
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j&8~X2?*  
//启动子线程 \DGm[/P  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; jh8%Xu]t  
for(int i=0;i<nStartPos.length;i++) Pu axS  
{ #3/l4`/j  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }T(|\ X  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), G]&:">&R  
nStartPos,nEndPos,i); 9lA YCsX  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bk^ :6>{K  
fileSplitterFetch.start(); &BE[=& |  
} ]$*N5Y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), q{ctHsQ(9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ) mv}u~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ao7|8[  
nEndPos = " + nFileLength); \uanQ|Nu  
// fileSplitterFetch[nPos.length-1].start(); *xLMs(gg  
J`"1
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;=uHK'{  
//等待子线程结束 -@J;FjrXmP  
//int count = 0; 7r}gS2d  
//是否结束while循环 KrbNo$0%  
boolean breakWhile = false; $X\BO&  
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while(!bStop) G_AAE#r`  
{ $B$=,^)3  
write_nPos(); w"l8M0$m  
Utility.sleep(500); z*9/"M  
breakWhile = true; +Z{4OJK  
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for(int i=0;i<nStartPos.length;i++) Rj E,Wn  
{ h+$_:](PC  
if(!fileSplitterFetch.bDownOver) H!45w;,I  
{ h_CeGl!M}  
breakWhile = false; :fj}J)9'xW  
break; ]j{S' cz  
} 3'.OghI  
} 01w=;Q  
if(breakWhile) zBjqYqZ<+  
break; n*O/X  
@
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//count++; z5{I3 Y!1  
//if(count>4) ^ePSI|EW  
// siteStop(); '2.F-~  
} ~F' $p  
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System.err.println("文件下载结束！"); @9c^{x\4  
} ]gmf%g'C  
catch(Exception e){e.printStackTrace ();} H%sQVE7m  
} 3cfkJ|fuwe  
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//获得文件长度 G
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public long getFileSize() }
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{ 1DLQZq  
int nFileLength = -1; ^SjGNg^ 7D  
try{ {)%B?75~  
URL url = new URL(siteInfoBean.getSSiteURL()); riBT5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); J#X7Ss  
httpConnection.setRequestProperty("User-Agent","NetFox"); p 3_Q  
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int responseCode=httpConnection.getResponseCode(); qi)(\  
if(responseCode>=400) rgP$\xn-  
{ ]T*{M  
processErrorCode(responseCode); '+}hVfN  
return -2; //-2 represent access is error g
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} -iW[cj R`$  
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String sHeader; q,*IR*B:a  
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for(int i=1;;i++) o?%x!m>  
{ Z4(2&t^  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); MT V
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//Utility.log(in.readLine()); -({\eL$n  
sHeader=httpConnection.getHeaderFieldKey(i); 7C 4Njei"  
if(sHeader!=null) w6E?TI  
{ >"Hj=?  
if(sHeader.equals("Content-Length")) F^aD!O ~  
{ #Y{"`5>  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Et- .[  
break; ,O-lDzcw  
} a;h:o>Do5  
} k?";$C}#  
else oS`F Yy  
break; dIf Jr}ih  
} -jyD!(  
} ZPMEN,Dw  
catch(IOException e){e.printStackTrace ();} t7~mW$}O  
catch(Exception e){e.printStackTrace ();} Y]n^(V  
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Utility.log(nFileLength); cX&c%~  
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return nFileLength; *%fOE;-?  
} cKxJeM07  
\u)(+t{  
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//保存下载信息（文件指针位置） -\I0*L'$|\  
private void write_nPos() o?X\,}-s  
{ @ J"1!`  
try{ r*3;gyG.,#  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6-JnT_  
output.writeInt(nStartPos.length); x x 'XR'zK  
for(int i=0;i<nStartPos.length;i++) \fKv+  
{ BPPhVE  
// output.writeLong(nPos); 'WOWm$2  
output.writeLong(fileSplitterFetch.nStartPos); 0qTa@y  
output.writeLong(fileSplitterFetch.nEndPos); lS,Hr3Lz  
} w?/,LV  
output.close(); >a0;|;hp  
} W35nnBU  
catch(IOException e){e.printStackTrace ();} V}JW@  
catch(Exception e){e.printStackTrace ();} hyBSS,I  
} /!
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//读取保存的下载信息（文件指针位置） x##Iv|$  
private void read_nPos() 5I<?HsK@  
{ XRz.R/  
try{ 0p#36czqy  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); J7$=f~$  
int nCount = input.readInt(); QvqBT  
nStartPos = new long[nCount]; HL)1{[|`  
nEndPos = new long[nCount]; ZWr\v!4  
for(int i=0;i<nStartPos.length;i++) cg$~.ytPK  
{ )GR^V=o7,Y  
nStartPos = input.readLong(); H(g&+Wcu=  
nEndPos = input.readLong(); xE9s=}  
} 57oY]NT?  
input.close(); 2AlLcfAW  
} g$:2c7uL  
catch(IOException e){e.printStackTrace ();} g%+nMjif  
catch(Exception e){e.printStackTrace ();} ?,Hk]Rl3  
} PC3wzJ\\S  
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private void processErrorCode(int nErrorCode) Pjx9@i  
{ @ce4sSo  
System.err.println("Error Code : " + nErrorCode); ^L[Z+7|  
} \t1vYIY]T  
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//停止文件下载 3$RII-}>  
public void siteStop() WUxr@0  
{ p@^2.O+  
bStop = true; tG{Vn+~/  
for(int i=0;i<nStartPos.length;i++) 6)?TWr'Ke  
fileSplitterFetch.splitterStop(); Dg]i};
 
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} yn=1b:kid  
} '}}DPoV  
//负责部分文件的抓取 0xjV*0?s  
**FileSplitterFetch.java w}E?FEe.  
*/ M0]fh5O  
package NetFox; qVY\5`f@  
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import java.io.*; JD>!3>S)?  
import java.net.*; N1SRnJu<f  
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:3G9YjzC}  
public class FileSplitterFetch extends Thread { LZ@^ A]U  
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String sURL; //File URL \Z~m6;  
long nStartPos; //File Snippet Start Position Psv-y  
long nEndPos; //File Snippet End Position M,[ClQ 9  
int nThreadID; //Thread's ID "q%)we  
boolean bDownOver = false; //Downing is over .p5*&i7  
boolean bStop = false; //Stop identical s}A]lY  
FileAccessI fileAccessI = null; //File Access interface "y`?KY$[N  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException B O"+m  
{ Ylf6-FbF  
this.sURL = sURL; 0|U<T#t8?  
this.nStartPos = nStart; jXdn4m/O  
this.nEndPos = nEnd; 712i|  
nThreadID = id; M\]E;C'"U  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Ky=&C8b<  
} H4pjtVBr  
/)G9w]|T  
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public void run() g5?Fo%W  
{ D?E5p.!A  
while(nStartPos < nEndPos && !bStop) Z,2
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{ 3)7'dM  
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*zx;81X=  
try{ $51#xe  
URL url = new URL(sURL); 6ZM<M7(V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z]6D0b  
httpConnection.setRequestProperty("User-Agent","NetFox"); Rbl(oj#  
String sProperty = "bytes="+nStartPos+"-"; ~jPe9  
httpConnection.setRequestProperty("RANGE",sProperty); [m"X*ZF  
Utility.log(sProperty); \gzNM
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InputStream input = httpConnection.getInputStream(); n b{8zo  
//logResponseHead(httpConnection); 5yQgGd)  
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byte[] b = new byte[1024]; 3sL#_@+yz  
int nRead; 3j3AI7c  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) =EG[_i{r  
{ c2i^dNp_  
nStartPos += fileAccessI.write(b,0,nRead); xE}q(.]  
//if(nThreadID == 1) r"4:aKF>  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); aR3W9  
} /
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\;sUJr"$  
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Utility.log("Thread " + nThreadID + " is over!"); ?$gEX@5h  
bDownOver = true; :8rqTBa`  
//nPos = fileAccessI.write (b,0,nRead); X-%*`XG'  
} v<c8qg  
catch(Exception e){e.printStackTrace ();} 08twcY;&k  
} a]Lr<i8#%  
} /1^%32c  
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//打印回应的头信息 :JOF!Q  
public void logResponseHead(HttpURLConnection con) \:Nbl<9(9  
{ u=4tW:W,  
for(int i=1;;i++) jKtbGVZ7r  
{ HID;~Ne  
String header=con.getHeaderFieldKey(i); U>{z*D  
if(header!=null) \_+d*hHF~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); =T+<>/[  
Utility.log(header+" : "+con.getHeaderField(header)); K}*s^*X  
else {?t=*l\S{w  
break; oEfKL
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} z,^baU  
} T%:}/@
 
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public void splitterStop() -ERDWY  
{ 'Yj/M  
bStop = true; M,7v}[Tbl  
} m. XLpD  
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} T[c;},  
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&L;0%
 
/* p6sXftk  
**FileAccess.java x
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*//文件访问(定位，写) }2G'3msx  
package NetFox; 4D0"Y#&G  
import java.io.*; Ut0oh  
sv =6?uYW  
Q xKC5`1  
public class FileAccessI implements Serializable{ 2x t 8F  
}+,;wj~  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C?X^h{Tp  
RandomAccessFile oSavedFile; 6=iz@C7r  
long nPos; 1_f(;WOg  
)88z=5.  
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public FileAccessI() throws IOException r 5:DIA!  
{ xa??OT`(  
this("",0); 4OC^IS  
} 6"z:s-V  
:<!a.%=  
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public FileAccessI(String sName,long nPos) throws IOException A-qdTJP  
{ )}tI8  
oSavedFile = new RandomAccessFile(sName,"rw"); ~CQsv`
 
this.nPos = nPos; [a`89'"z  
oSavedFile.seek(nPos); 0M>+.}e+  
} }[\l$sS  
;&oS=6$  
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public synchronized int write(byte[] b,int nStart,int nLen) ~#C7G\R  
{ srLXwoN[  
int n = -1; wL\OAM6R  
try{ pxDkf|*  
oSavedFile.write(b,nStart,nLen); JUHmIFjZ  
n = nLen; a~>+I~^K5q  
} ")}^\Om  
catch(IOException e) uD4on}
 
{ OWx-I\:  
e.printStackTrace (); Y{ijSOl3  
} EyO=M~nsS  
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return n; clV3x`z  
} ?0*,x)t  
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}OL?k/w  
} r$T\
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/* ~.7/o0'+  
**SiteInfoBean.java +Nn $  
*/ l1HMH?0|  
package NetFox; hg4d]R,  
>xsbXQ>.
 
t/%{R.1MN  
public class SiteInfoBean { ]ie38tX$  
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[J{\Ke0<e1  
private String sSiteURL; //Site's URL H{M7_1T  
private String sFilePath; //Saved File's Path !:Z lVIA  
private String sFileName; //Saved File's Name 08czP-)OZ  
private int nSplitter; //Count of Splited Downloading File [`J91=  
H?oBax:  
+{#65z  
public SiteInfoBean() K-,4eq!
 
{//nSplitter的缺省值为5 7M8oI.?C|  
//default value of nSplitter is 5 f.)z_RyGd  
this("","","",5);
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} @I"&k!e<2  
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ty 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)  A:b(@'h  
{ {'#1do}{  
sSiteURL= sURL; 'Dn\.x^]1  
sFilePath = sPath; _+7+90u  
sFileName = sName; 11VtC)  
this.nSplitter = nSpiltter; epN
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} h*>%ou  
=Gv*yR*]t  
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public String getSSiteURL() jlxY|;gZ-0  
{ dvAG}<  
return sSiteURL; t]IHQ8  
} Bo,>blspw  

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public void setSSiteURL(String value) 6,;dU-A+  
{ NiH =T  
sSiteURL = value; k=W~ot&  
} nnOgmI7  
&t~NR$@  
,xw1B-dx  
public String getSFilePath() m]+~F_/  
{ hpc&s  
return sFilePath; nR]*RIp5  
} .C\2f+(U  
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public void setSFilePath(String value) =Vm3f^  
{ a<0q%Ax  
sFilePath = value; BOOb{kcg  
} Kf-XL),3l  
'7Mz]@  
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public String getSFileName() cQkj{u  
{ Y\Z6u)  
return sFileName; )&DsRA7v  
} l 88n*O  
KPVu-{_Fi  
`Ez8!d{MD8  
public void setSFileName(String value) =xQPg0g  
{ \gu8 ~zK  
sFileName = value; <5E)6c_W)  
} 8BrC@L2E0  
L@'2}7N1%  
/d+v4GIB  
public int getNSplitter() ;m7~!m)  
{ b<!' WpY-  
return nSplitter; ^&\pY  
} o|u4C{j  
.sc80i4  
7;c^*"Ud  
public void setNSplitter(int nCount) CIui9XNU  
{ ] g<$f#S  
nSplitter = nCount; NT2XG&$W>  
} k.7!)jL7  
} qzNXz_#+u  
n=)LB& m  
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/* lI%RdA[  
**Utility.java rizjH+  
*/ )3A+Ell`  
package NetFox; Pl!E$   
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{Mj- $G"  
public class Utility { }Ml BmD  
Zn0a)VH%  
@{UUB=}9  
public Utility() ~Ad2L*5S  
{ ~3-"1E>Rgy  
:ssj7wl :  
}t"K(oamm  
} J5{  
2D:,(  
//线程睡眠 .%dGSDru  
public static void sleep(int nSecond) VxS3lR=  
{ o=#ym4hJ%  
try{ ]%I\FefT  
Thread.sleep(nSecond);  j'Jb+@W?  
} .#Nf0  
catch(Exception e) GqNOWK2O  
{ %I9f_5BlT8  
e.printStackTrace (); /}2Y-GOU  
} `#w#!@s#@  
} '<vb_8.  
]'?Ue7  
//日志  3s|:7  
public static void log(String sMsg) pH.&C 5kA  
{ 1_Ks*7vuq  
System.err.println(sMsg); 2z"<m2a  
} Z9NN
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oemN$g&7  
T)%6"rPL3!  
public static void log(int sMsg) "f<gZsb  
{ 5-ED\-  
System.err.println(sMsg); oK-d58 sM  
} QZG<sZ0"  
} yH]Q;X'  
7sQHz.4  
~OsLbz:  
/* z;P#  
**TestMethod.java KAD2_@l  
*/ U}DE9e{/!  
package NetFox; ?>{u@tYL  
u=qaz7E  
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public class TestMethod { ybsw{[X>M  
)eT>[['fm  
D!O
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public TestMethod() !W8=\:D[  
{ ///xx/weblogic60b2_win.exe +jZa A/  
try{ N?-ZvE\C  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 'I+M*Iy  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 8f[ztT0`g  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 4)OOj14-V  
fileFetch.start(); QW,:'\G  
} %XeN_ V  
catch(Exception e){e.printStackTrace ();} {]8|\CcY?  
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eR>
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} MZX)znO  
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)92(C  
public static void main(String[] args) +>1?ck  
{ h%$^s0w  
new TestMethod(); QwpX3 k6  
} 1eV&oN#  
} U^GVz%\  
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