http断点续传简单实现（java)

/* " gwm23Rpj  
**SiteFileFetch.java #d$d&W~gE  
*/ 0n7HkDo  
package NetFox; YU*46 hA1B  
import java.io.*; }v,W-gA  
import java.net.*;  S/)  
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public class SiteFileFetch extends Thread { ByC1I.B`  
mp muziH  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ,2E`:#$  
long[] nStartPos; //开始位置 moZ)|y  
long[] nEndPos; //结束位置 nqUH6(  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~x9 W{B]  
long nFileLength; //文件长度 )sMAhk|  
boolean bFirst = true; //是否第一次取文件 8UjCX[v  
boolean bStop = false; //停止标志 wV]sGHuF}  
File tmpFile; //文件下载的临时信息 Y+}OClS  
DataOutputStream output; //输出到文件的输出流 B6^w{eXN  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） n">?LN-DC  
public SiteFileFetch(SiteInfoBean bean) throws IOException *_}IeNc  
{ l;.[W|  
siteInfoBean = bean; ".Tf<F  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); v GulM<YY  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); N8u_=b{X  
if(tmpFile.exists ()) hXj* {vT  
{ >Lo6='G  
bFirst = false; 7r:nMPX  
read_nPos(); 6C@0[Q\ER  
} 8HHgN`_  
else }7f 1(#{7  
{ S
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nStartPos = new long[bean.getNSplitter()]; H@ 1[SKBl  
nEndPos = new long[bean.getNSplitter()]; kG_&-b  
} e2,<,~_K6  
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} bw<~R2[  
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public void run() |
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{ Q_UCF'f;}  
//获得文件长度 1+.y,}F6b  
//分割文件 +J}k_'4&  
//实例FileSplitterFetch RBHqLg(  
//启动FileSplitterFetch线程 'T#<OR  
//等待子线程返回 *NX*/(Q  
try{ K!$\REs  
if(bFirst) o} bj!h]N  
{ ^*4(JR   
nFileLength = getFileSize(); oeRYyJ  
if(nFileLength == -1) ^OGH5@"  
{ $bM#\2'  
System.err.println("File Length is not known!"); SIyS.!k>  
} )PLc+J.I  
else if(nFileLength == -2) 7J)Hwl  
{ AQ_#uxI'oa  
System.err.println("File is not access!"); NjCLL`?f  
} f;qKrw  
else 5y 'ycTjY  
{ ?_<UOb*  
for(int i=0;i<nStartPos.length;i++) ;d'O.i=  
{ ` wsMybe#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); N5I W@?4  
} [W7\c;Do  
for(int i=0;i<nEndPos.length-1;i++) a 7mKshY(  
{ 6iAc@  
nEndPos = nStartPos[i+1]; t]YLt ,  
} ZLFdnC@  
nEndPos[nEndPos.length-1] = nFileLength; 3YZ3fhpw  
} 30T:* I|  
} lhvZ*
[[<)  
;7hX0AK  
]jT[dX|?  
//启动子线程 PrYWha=c-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; p%YvP  
for(int i=0;i<nStartPos.length;i++) 8^ZM U{  
{ /hj9Q!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2%No>w}/2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8G
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nStartPos,nEndPos,i); '-1jWw:8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H9a3rA>  
fileSplitterFetch.start(); '/]Aaf@U8  
} i
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bD^ob.c.A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); B0?@k  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !j\&BAxTEk  
nEndPos = " + nFileLength); sN \}Q#:8  
// fileSplitterFetch[nPos.length-1].start(); w<^2h}5  
E/Gs',Y  
UBk 5O&  
//等待子线程结束 )<&CnK  
//int count = 0; [T?6~^m=  
//是否结束while循环 ^eT>R,aB  
boolean breakWhile = false; }n&JZ`8<s  
q,h.W JI  
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while(!bStop) ,i((;/O6  
{ U3iy
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write_nPos(); ^xu)~:} i  
Utility.sleep(500); /r 2.j3:l  
breakWhile = true; U~`^Y8UF  
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(DaP~*c3cC  
for(int i=0;i<nStartPos.length;i++) tNNg[;0  
{ eOnl sx/  
if(!fileSplitterFetch.bDownOver) lSsFI30  
{ \kRJUX!s  
breakWhile = false; TKutO0  
break; {_gj>n(1  
} G5@fqh6ws  
} n'(n4qH2#s  
if(breakWhile) 9%'HB\A  
break; N`GwL aF  
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I$  
s*U&[7P  
//count++; 4!RI2?4V  
//if(count>4) _A0avMD}  
// siteStop(); |4*2xDcl  
} v7I*W/  
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,rPyXS9Sa{  
System.err.println("文件下载结束！"); OL+40J  
} 4Tw1ga
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catch(Exception e){e.printStackTrace ();} 1|$Rzt%ge  
} \$Qm2XKrK  
g.VIe  
#)eJz1~  
//获得文件长度 T#;*I#A:  
public long getFileSize() (ZR"O8  
{ z:,!yU c  
int nFileLength = -1; ><[.  
try{ L6}x3  
URL url = new URL(siteInfoBean.getSSiteURL()); 5'[X&r%#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?)<XuMh  
httpConnection.setRequestProperty("User-Agent","NetFox"); 31\^9w__8  
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8$olP:d  
int responseCode=httpConnection.getResponseCode(); HWAqJb [  
if(responseCode>=400) fmN)~-DV9`  
{ bo/!u s#  
processErrorCode(responseCode); 6spk*
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return -2; //-2 represent access is error c<x6_H6[8  
} FDC{8e  
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String sHeader; }iloX#  
"x^bl+_"  
@S:/6__  
for(int i=1;;i++) +# >%bq x  
{ 9\0 K%LL  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); p~co!d.q/}  
//Utility.log(in.readLine()); G* 6<pp  
sHeader=httpConnection.getHeaderFieldKey(i); LK5H~FK  
if(sHeader!=null) J>PV{N  
{ PFw"ICs  
if(sHeader.equals("Content-Length")) {G&g+9c&  
{ [SvwJIJJ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); :_zKUv]  
break; WcG&W>  
} kl9z;(6p  
} =*U24B*U93  
else 3NWAyCq-  
break; #OTsD+2Za=  
} O~xmz!?=  
}
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catch(IOException e){e.printStackTrace ();} mjHY-lK  
catch(Exception e){e.printStackTrace ();} Tq8r SZi  
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Utility.log(nFileLength); 'a*IZb-M  
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return nFileLength; ,oe{@z{*@  
} Dw3! ibg  
Oc`fQqYy  
BE)l77=/  
//保存下载信息（文件指针位置） ^*Fkt(ida  
private void write_nPos() M3kE91  
{ 20)Il:x  
try{ #!Fs
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output = new DataOutputStream(new FileOutputStream(tmpFile)); [\yI<^_
a  
output.writeInt(nStartPos.length); d:''qgz`  
for(int i=0;i<nStartPos.length;i++) =1qkoc~  
{ [_-K  
// output.writeLong(nPos); AK =k@hT  
output.writeLong(fileSplitterFetch.nStartPos); @=c='V]  
output.writeLong(fileSplitterFetch.nEndPos); Nb1la
wC  
} 7d5x4^EYE  
output.close(); /K<Nlxcm  
} _C\b,D}p  
catch(IOException e){e.printStackTrace ();} O
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catch(Exception e){e.printStackTrace ();} .Ps;O  
} XN;eehB?aE  
H!u:P?j@\  
8=9sIK2  
//读取保存的下载信息（文件指针位置） 9g"H9)EZ^  
private void read_nPos() ]Ox.6BKjDP  
{ U\{Z{F%8  
try{ ENzeVtw0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =qvU9p2o  
int nCount = input.readInt(); z
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nStartPos = new long[nCount]; Z}wAh|N-  
nEndPos = new long[nCount]; H5{J2M,f  
for(int i=0;i<nStartPos.length;i++) wSMgBRV#^  
{ CHB{P\WF  
nStartPos = input.readLong(); "/"k50%  
nEndPos = input.readLong(); 
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} Z5=!R$4  
input.close(); V'$ eun  
} 4J1Q])G9  
catch(IOException e){e.printStackTrace ();} fZO/HzX  
catch(Exception e){e.printStackTrace ();} *79<ypKG$  
} `h'^S,'*  

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private void processErrorCode(int nErrorCode) n
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{ RFdN13sJv  
System.err.println("Error Code : " + nErrorCode); Q~kwUZ  
} u4'Lm+&O  
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//停止文件下载 PhS"tOGtX  
public void siteStop() {TNAK%'v  
{ |D~MS`~qd5  
bStop = true; ~0NZx8qG  
for(int i=0;i<nStartPos.length;i++) )94R\f  
fileSplitterFetch.splitterStop(); )".gjW8{#L  
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} fomkwN  
} MqqS3   
//负责部分文件的抓取 h:;~)={"X  
**FileSplitterFetch.java %WNy=V9txp  
*/ w <ID<  
package NetFox; u+'=EGl  
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import java.io.*; G-qxQD1wK  
import java.net.*; |F<aw?%  
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public class FileSplitterFetch extends Thread { }?JO[Q +
 
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ZUh<2F  
String sURL; //File URL 4aRYz\yT=  
long nStartPos; //File Snippet Start Position bk<3oI  
long nEndPos; //File Snippet End Position dM') <lF  
int nThreadID; //Thread's ID Cur)|  
boolean bDownOver = false; //Downing is over qr@,92_  
boolean bStop = false; //Stop identical QNo}nl/N  
FileAccessI fileAccessI = null; //File Access interface 1/m/Iw@  
86_Zh5:  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Q,$x6YwE  
{ ;i]cmy  
this.sURL = sURL; R Q8okA  
this.nStartPos = nStart; 5s>9v  
this.nEndPos = nEnd; /~yqZD<O  
nThreadID = id; &jJgAZ!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 q\,H9/.0k  
} T:ck/:ZH  
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public void run() $=bN=hE  
{ pUmB h  
while(nStartPos < nEndPos && !bStop) yE7pCgXt  
{ ZoUfQ!2*  
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try{ ?`vb\K<5H;  
URL url = new URL(sURL); 4k#6)e  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); K5KN}sRs"  
httpConnection.setRequestProperty("User-Agent","NetFox"); +bXZE  
String sProperty = "bytes="+nStartPos+"-"; ~ce.&C7cR  
httpConnection.setRequestProperty("RANGE",sProperty); *0U(nCT&m  
Utility.log(sProperty); 2
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InputStream input = httpConnection.getInputStream(); *~vRbD$q  
//logResponseHead(httpConnection); 'i,<j s3\f  
P.wINo  
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byte[] b = new byte[1024]; @iaN@`5I6s  
int nRead; LDNp
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) iZ:-V8{  
{ j7W_%Yk|E  
nStartPos += fileAccessI.write(b,0,nRead); Fg~,1[8w<  
//if(nThreadID == 1) Q.fBuF  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #?/.LMn{  
} 8RK\B%UW  
A@#dv2JzP  
@bPJ}C  
Utility.log("Thread " + nThreadID + " is over!"); nQ+{1 C  
bDownOver = true; JdAjKN  
//nPos = fileAccessI.write (b,0,nRead); 7#&sG  
} jPd<h{js  
catch(Exception e){e.printStackTrace ();} q^Z\V?  
} v`fUAm/  
} eDm,8Se  
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#B?7{#.1  
//打印回应的头信息 C+iP @~  
public void logResponseHead(HttpURLConnection con) OY)x Kca  
{ Qw^tzP8  
for(int i=1;;i++) md_Ld /  
{ KIS.4nt#d"  
String header=con.getHeaderFieldKey(i); OlK2<<  
if(header!=null) 51&T`i  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); V^ :\/EU  
Utility.log(header+" : "+con.getHeaderField(header)); UWnH
2  
else WX[ycm8  
break; Gnw>%f1@u  
} RS1oPY  
} 3_-#
 
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public void splitterStop() ks;%f34  
{ u>eu47"n!  
bStop = true; >!2'|y^  
} 8 2qe|XD4p  
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} 5Q88OxH  
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/* 9D<HJ(  
**FileAccess.java vfm-K;,#  
*//文件访问(定位，写)
B8&@Qc@~  
package NetFox; c[I,Sveq  
import java.io.*; ..t=
Y#  
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public class FileAccessI implements Serializable{ 9+:Trc\%N
 
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 u"%fz8v  
RandomAccessFile oSavedFile; (07d0<<[  
long nPos; "xOeBNRjV  
9Dl \SF[  
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public FileAccessI() throws IOException 6PH*]#PfoD  
{ nAzr!$qbNv  
this("",0); DH^^$)  
} erqB/C  
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0#JBz\  
public FileAccessI(String sName,long nPos) throws IOException - \QtE}|4  
{ El%(je,|  
oSavedFile = new RandomAccessFile(sName,"rw"); *l//r V?l  
this.nPos = nPos; !xI![N^  
oSavedFile.seek(nPos); 3Z0\I\E  
} S6mmk&n  
4pqZ!@45|  
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public synchronized int write(byte[] b,int nStart,int nLen) <Va>5R_
d<  
{ ^Ram8fW  
int n = -1; s__g*%@B b  
try{ UwU]l17~  
oSavedFile.write(b,nStart,nLen); zMKL: Um"  
n = nLen; yKJ^hv"#  
} 
>=H8>X  
catch(IOException e) ~}w8UO  
{ BpT&vbY  
e.printStackTrace (); RHbw
q
]  
} t3G'x1  
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e=jO_[  
return n; bSLj-vp  
} ;>N ~,Q  
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} "=.|QKC1`  
*q{UipZbx  
=Qrz|$_rv  
/* -e>)yM `i  
**SiteInfoBean.java ?W_U{=anl  
*/ :8rCCop Uv  
package NetFox; sA}R!  
*.g?y6d  
R:N-y."La.  
public class SiteInfoBean { [[Z>(d$8  
|m- `, we  
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private String sSiteURL; //Site's URL L0tK
Ipk  
private String sFilePath; //Saved File's Path S8m&Rj3O&  
private String sFileName; //Saved File's Name D5u"4\g<&  
private int nSplitter; //Count of Splited Downloading File (}1f]$V  
"|`9{/]  
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public SiteInfoBean() q}Z T?Xk?  
{//nSplitter的缺省值为5 yuEOQ\!(u  
//default value of nSplitter is 5 ue<<Y"NR  
this("","","",5); F t/ x5  
} }TJ|d=  
9t.yP;j\Y  
+|)1_NK  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) /? 1Yf  
{ ID#qKFFW  
sSiteURL= sURL; Q0Qm0B5eY  
sFilePath = sPath; k<zGrq=8J  
sFileName = sName; Ks2%F&\cE  
this.nSplitter = nSpiltter; %C0O?q  
pm@Z[g  
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} E(kpK5h{  
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public String getSSiteURL() oV>AFs6  
{ zy6(S_j  
return sSiteURL; a<jE25t  
} |#:dC #  
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public void setSSiteURL(String value) gzCMJ<3!D  
{ I S8nvx\  
sSiteURL = value; 1idjX"'  
} a {$k<@Ww  
K6*UFO4}i  
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public String getSFilePath() i2a"J&,6O  
{ L_1_y, 0N  
return sFilePath; |z.GSI_!)  
} bL],KW;Q  
s/vOxGc  
X#I`(iHY  
public void setSFilePath(String value) m2q;^o:J  
{ 'h6}cw+K  
sFilePath = value; fMEv85@JL  
} aU<D$I  
roj04
|  
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public String getSFileName() A='+tJa  
{ Z F yX@#B9  
return sFileName; PT@e),{~o9  
} ph12x: @B  
]n]uN~)9  
7M#$: Fdb  
public void setSFileName(String value) NQiecxvt=  
{ l9NOzAH3  
sFileName = value; ddq 1NW  
} 1;:t~Y  
@23R
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gLSG:7m@  
public int getNSplitter() `TD%M`a  
{ ?I2k6%a  
return nSplitter; ?WQd  
} Fr3d#kVR  
pG F5aF7T  
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public void setNSplitter(int nCount) x"llX  
{ M`+e'vdw  
nSplitter = nCount; *JY`.t  
} _E1]cbIo  
} 
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/* .W@4vrp
@  
**Utility.java K[LVT]3 n  
*/ mj~N]cxB  
package NetFox; (\mulj  
#S53u?JV8  
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public class Utility { N{V5 D  
&!DZW5  
q?Ku}eID3  
public Utility() UC+7-y,
  
{ le^_6|ek  
x<*IF,o  
aEEz4,x_  
} uVq5fT`B  
V3 _b!  
//线程睡眠 Q3Z%a|3W  
public static void sleep(int nSecond) ~ACP%QM=  
{ SGBVR^  
try{ "wF ?Hamz  
Thread.sleep(nSecond); \at-"[.  
} o[6vxTH  
catch(Exception e) <=m 30{;f  
{ ]D?# \|  
e.printStackTrace (); fzRyG-cEpj  
} @!":(@3[  
} |z#m  
Iu-'o  
//日志 ;h,R?mU  
public static void log(String sMsg) ;-9zMbte:  
{ Z[})40[M  
System.err.println(sMsg); UVT
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} $(KIB82&  
?
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M$&WM{Pr^  
public static void log(int sMsg) Q3BLL`W~  
{ 9QC"Od9H  
System.err.println(sMsg); Y/^[qD  
} |.Nr.4Yp  
} RP~vB#}  
1#>&p%P!  
J@k
tj(  
/* 6^]`-4*W  
**TestMethod.java @Xq&t}*8  
*/ "M9TB. O  
package NetFox; V~J*49t&2J  
l$qStL*8O  
YeRcf`  
public class TestMethod { .K
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om".j  
` $.X[\*U  
public TestMethod() `z3|M#r\;  
{ ///xx/weblogic60b2_win.exe $ DDSN  
try{ } g3HoFC  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); QmH/yy3.%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); HUU >hq9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Kf05<J!  
fileFetch.start(); &*(n<5wt  
}
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catch(Exception e){e.printStackTrace ();} pAJ=f}",]E  
:u>W&D  
9E
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} m\*&2Na  
~:/%/-^  
``(}4a  
public static void main(String[] args) [^?13xMb  
{ UOR _M5  
new TestMethod(); !y>lOw})Q  
} yfSiByU  
} DC
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