http断点续传简单实现（java)

/* ^kC!a>&  
**SiteFileFetch.java nVoWER:  
*/ `<~=6H  
package NetFox; OqRRf  
import java.io.*; B1FJAKI);  
import java.net.*; hP'4PLK  
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public class SiteFileFetch extends Thread { IS!OO<  
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SiteInfoBean siteInfoBean = null; //文件信息Bean KX;JX*)J  
long[] nStartPos; //开始位置 |ssl0/nk  
long[] nEndPos; //结束位置 3O-vO=D  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 oR~d<^z(  
long nFileLength; //文件长度 du~V=%9  
boolean bFirst = true; //是否第一次取文件 h*40jZ  
boolean bStop = false; //停止标志 YL!{oHs4  
File tmpFile; //文件下载的临时信息 ' =5B  
DataOutputStream output; //输出到文件的输出流 smQl^ 6a  

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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） LjGZp"&{  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1,h:|  
{ X=1o$:7  
siteInfoBean = bean; N2HD=[*cr  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); __7}4mA  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .hG*mXw>  
if(tmpFile.exists ()) )qMbk7:v\  
{ opm_|0  
bFirst = false; jDQ?b\^  
read_nPos(); -G/qfd|s/  
} Fx.Ly]L  
else t_!p({  
{ `C|];mf(#  
nStartPos = new long[bean.getNSplitter()]; KiI+ V;
o  
nEndPos = new long[bean.getNSplitter()]; o9sPyY$aQ  
} R ai 04  
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} g"|>^90  
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public void run() Q~0>GOq*  
{ ffR%@  
//获得文件长度 6@8t>"}  
//分割文件 O<V 4j,  
//实例FileSplitterFetch %1jcY0zEQ  
//启动FileSplitterFetch线程 pZ\7!rON  
//等待子线程返回 ~ffT
}q7^  
try{ R)*DkL!  
if(bFirst) -L]-u6kC[  
{ 1|"BpX~D  
nFileLength = getFileSize(); x$o^;2Z  
if(nFileLength == -1) bFajK;  
{ ILAn2W  
System.err.println("File Length is not known!"); )kI**mI}  
} 7p]Izx8][  
else if(nFileLength == -2) U'9z.2"}9  
{ q!'p   
System.err.println("File is not access!"); _h#I}uJ~  
} TvDC4tm-:  
else 3Ji$igL  
{ g6lWc@]F  
for(int i=0;i<nStartPos.length;i++) AnX<\7bc}  
{ ZfqN4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 6MY<6t0a  
} hchG\i  
for(int i=0;i<nEndPos.length-1;i++) m#8[")a$"  
{ 7XyCl&Dc:  
nEndPos = nStartPos[i+1]; X|Y(*$?D7  
} Ky%lu^  
nEndPos[nEndPos.length-1] = nFileLength; 9-{=m+|b  
} o.fqJfpj  
} m Rw0R{  
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//启动子线程 }kr?+)wB  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;XawEG7" U  
for(int i=0;i<nStartPos.length;i++) EI 35&7(  
{ V+lF|CZb5  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xIa7F$R 0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), D 6
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nStartPos,nEndPos,i); jci,]*X4  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7g"u)L&32  
fileSplitterFetch.start(); ^O+(eA7E  
} [F-GaaM  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;TWLo_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3rKJ<(-2/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]'(D*4  
nEndPos = " + nFileLength); n:`f.jG |  
// fileSplitterFetch[nPos.length-1].start(); [C0v-  
7LVG0A2>7  
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//等待子线程结束 9K`_P] l2z  
//int count = 0; 0Z6geBMc  
//是否结束while循环 I@9'd$YY  
boolean breakWhile = false; Is7BJf  
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while(!bStop) [DM0'4  
{ ^ UmYW  
write_nPos(); z.SC^/\o|  
Utility.sleep(500); bqAW  
breakWhile = true; [#q>Aq$11  
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for(int i=0;i<nStartPos.length;i++) LQ# E+id&  
{ C{zp8 A(Dh  
if(!fileSplitterFetch.bDownOver) [rT.k5_  
{ [|KvlOvP  
breakWhile = false; ?PT>V,&  
break; @ps(3~?7  
} {jz`K1  
} qt~=47<d  
if(breakWhile) :HO5 T  
break; z2uL[deN'"  
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//count++; [^5;XD:%&l  
//if(count>4) @9B*V~ <  
// siteStop(); \CMZ_%~wU  
} A<X?1$  
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System.err.println("文件下载结束！"); Q# B0JT1  
} $QC1l@[sM  
catch(Exception e){e.printStackTrace ();} ;Y^'$I2fR#  
} Zj_2>A  
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1[SG.  
//获得文件长度 06S R74  
public long getFileSize() ~Ba=nn8Cq  
{ W}CM;~*L  
int nFileLength = -1; uX6yhaOp|  
try{ x)~i`$  
URL url = new URL(siteInfoBean.getSSiteURL()); {p84fR1P  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); tR|dnC4U  
httpConnection.setRequestProperty("User-Agent","NetFox"); a]T:wUYG'  
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int responseCode=httpConnection.getResponseCode(); I x%>aee  
if(responseCode>=400) kUf i  
{ (aa2uctTn  
processErrorCode(responseCode); {rUg,y{v  
return -2; //-2 represent access is error eluN~T:W  
} 9 %T??-  
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String sHeader; T+<.KvO-  
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for(int i=1;;i++) cs+3&T:,*  
{ eThaH0  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); $eYL|?P50h  
//Utility.log(in.readLine()); KC6Cg?y^  
sHeader=httpConnection.getHeaderFieldKey(i); lvO6&sF1  
if(sHeader!=null) e7RgA1  
{ K*>%,mP$i  
if(sHeader.equals("Content-Length")) VVas>/0qr  
{ 5qb93E"C  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $a M5jH<  
break; f4"UI-8;n  
} ]4l2jY  
}
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else hIJtu;}zU  
break; h1w({<q*ov  
} l6/VJ~(}'  
} K92j BR  
catch(IOException e){e.printStackTrace ();} m4mE7Wn.3  
catch(Exception e){e.printStackTrace ();} O[Vet/^)  
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Utility.log(nFileLength); QqA=QTZ}  
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return nFileLength; i2,4:M)CV  
} 1RRE{]2v#  
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//保存下载信息（文件指针位置） v>8C}d^  
private void write_nPos() OETo?Wg1Z  
{ 3p0v  
try{ >h\y1IrAaG  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Eomfa:WL  
output.writeInt(nStartPos.length); 7D6`1&  
for(int i=0;i<nStartPos.length;i++) {&=+lr_h?  
{ YB38K(  
// output.writeLong(nPos); s1:Wrz?4  
output.writeLong(fileSplitterFetch.nStartPos); xyp{_ MZ  
output.writeLong(fileSplitterFetch.nEndPos); ^_WR) F'K  
} hNN>Pd~;  
output.close(); EeW ,-I  
} -S'KxC  
catch(IOException e){e.printStackTrace ();} !5`MiH  
catch(Exception e){e.printStackTrace ();} .-d'*$ yJ  
} J9Ao*IW~  
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//读取保存的下载信息（文件指针位置） XO+BZB`F  
private void read_nPos() M/N8bIC! Q  
{ vO}r(kNJ  
try{ bA^uzE  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _~<sb,W  
int nCount = input.readInt(); e"E8BU  
nStartPos = new long[nCount]; $.PRav  
nEndPos = new long[nCount]; RM;a]g*  
for(int i=0;i<nStartPos.length;i++) g#5R||r  
{ }"D;?$R!  
nStartPos = input.readLong(); ?I}RX~Tgg  
nEndPos = input.readLong(); fVbjU1N  
} $n\Pw  
input.close(); ]auvtm-[  
} b] 5weS-<  
catch(IOException e){e.printStackTrace ();} R#T-o,m  
catch(Exception e){e.printStackTrace ();} >qeDb0  
} Ykxk`SJ  
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private void processErrorCode(int nErrorCode) 6"&cQ>$xh  
{ d?zSwLsl  
System.err.println("Error Code : " + nErrorCode); g)Lf^  
} TeHJj`rdAU  
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//停止文件下载 i2=- su  
public void siteStop() W/Dd7G#IC  
{ L@N%S Sf
 
bStop = true; 0AQazhm  
for(int i=0;i<nStartPos.length;i++) 6G8No-#y  
fileSplitterFetch.splitterStop(); Rb6BY-/J  
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} [LYO'-g^F#  
} F%w!I 9  
//负责部分文件的抓取 ,lZ19B?WP  
**FileSplitterFetch.java =:H-9  
*/ %7#<K\])  
package NetFox; ;UQGi}?CD  
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import java.io.*; $L*gtZ  
import java.net.*; )/raTD  
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public class FileSplitterFetch extends Thread { c4H6I~2Na  
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String sURL; //File URL I dK*IA4  
long nStartPos; //File Snippet Start Position \Zj%eW!m  
long nEndPos; //File Snippet End Position H*=cw<  
int nThreadID; //Thread's ID }z`x-(V  
boolean bDownOver = false; //Downing is over hb`9Vn\-E  
boolean bStop = false; //Stop identical \|PiQy*_?  
FileAccessI fileAccessI = null; //File Access interface Z@bgJL83  
V(';2[)  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <ToS&  
{ CIW4E  
this.sURL = sURL; 6.@.k  
this.nStartPos = nStart; m{IlRf'  
this.nEndPos = nEnd; zMSwU]4I!  
nThreadID = id; R{g= N%O  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;K<VT\
 
} wm5&5F4:  
I}
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public void run() 0L}`fYf  
{ kckRHbeU  
while(nStartPos < nEndPos && !bStop) ,GSiSn  
{ +( LH!\
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#
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try{ de:@/-|  
URL url = new URL(sURL); +7.|1x;C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); KuR]X``2  
httpConnection.setRequestProperty("User-Agent","NetFox"); Y@FYo>0O  
String sProperty = "bytes="+nStartPos+"-"; l2F#^=tp  
httpConnection.setRequestProperty("RANGE",sProperty); E !kN h  
Utility.log(sProperty); '2^}de!E  
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InputStream input = httpConnection.getInputStream(); a\P:jgF  
//logResponseHead(httpConnection); +XWTu!  
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byte[] b = new byte[1024]; <*5S7)]BP  
int nRead; wB)y@w4k  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;[y( 14g  
{ gj^)T_E_  
nStartPos += fileAccessI.write(b,0,nRead); F_@B ` ,  
//if(nThreadID == 1) e{x>u(  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); b|i4me@  
} ~XR('}5D  
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Utility.log("Thread " + nThreadID + " is over!"); Ag8/%a~(  
bDownOver = true; Xu-~j!  
//nPos = fileAccessI.write (b,0,nRead); aO{@.  
} j@xIa-{*  
catch(Exception e){e.printStackTrace ();} bxa>:71  
} :<g0Ho?e  
} _7!ZnJrR
 
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//打印回应的头信息 6u_i>z  
public void logResponseHead(HttpURLConnection con) "Q@m7j)(  
{ DOWWG!mx  
for(int i=1;;i++) )Xdq+$w.  
{ v!I z&M:z  
String header=con.getHeaderFieldKey(i); )@!fLAT  
if(header!=null) !oH{=.w  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); I~l qg  
Utility.log(header+" : "+con.getHeaderField(header)); sc*R:"  
else rWr'+v?  
break; `l45T~`]$  
} c/Pql!h+  
} []>rYZ9bv  
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public void splitterStop() ^\PRzY  
{ ?NA$<0  
bStop = true; P%R!\i  
}  ?s,oH  

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} 1uw1(iL+  
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/* cW^LmA  
**FileAccess.java ^_#wo
"  
*//文件访问(定位，写) YeCnk:_ kg  
package NetFox; .]E(P   
import java.io.*; .u mqyU~  
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public class FileAccessI implements Serializable{ p@pb[Bx~[  
+pYgh8w@  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 w10~IP  
RandomAccessFile oSavedFile; |47t+[b  
long nPos; ^p(aZj3k  
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public FileAccessI() throws IOException /T6bc^nOW  
{ *Xnf}Ozx  
this("",0); ?=l
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} < }K9 50  
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public FileAccessI(String sName,long nPos) throws IOException d5-Q}D,P  
{ PxYK)n9&  
oSavedFile = new RandomAccessFile(sName,"rw"); h GA2.{  
this.nPos = nPos; G^{~'TZv%  
oSavedFile.seek(nPos); Xc[ym  
} IhzY7U)}T  
!,ODczWvh  
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public synchronized int write(byte[] b,int nStart,int nLen) by1q"\-,  
{ NK|U:p2H  
int n = -1; tD`^qMua  
try{ }Bv1fbD4U  
oSavedFile.write(b,nStart,nLen); xD*Zcw(vj~  
n = nLen; oL9<Fi  
} E 14DZ  
catch(IOException e) r.)n
>  
{ yLf9cS6=  
e.printStackTrace (); !RJ@;S  
} ItLR|LO9  
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return n; Pfs_tu  
} ,R=!ts[qi  
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} uPl7u1c  
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/* z~f;}`0  
**SiteInfoBean.java xJw" 8V<  
*/ 64b AWHv  
package NetFox; 1PxRj  
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public class SiteInfoBean { < e3] pM  
L[PqEN\i  
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private String sSiteURL; //Site's URL K'2N:.D:  
private String sFilePath; //Saved File's Path j&dCP
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private String sFileName; //Saved File's Name ()j)}F#Z`  
private int nSplitter; //Count of Splited Downloading File ax5n}  
H,<CR9@(5d  
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public SiteInfoBean() _*=4xmB.=  
{//nSplitter的缺省值为5 Ng<ic  
//default value of nSplitter is 5 *0oa2fz%  
this("","","",5); *DcIC]ao[  
} AHr^G'  
/V0Put  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) -N/n|{+F  
{ DNj<:Pdd)  
sSiteURL= sURL; $'}|/D  
sFilePath = sPath; Q65M(x+oy  
sFileName = sName; }^H(EHE  
this.nSplitter = nSpiltter; )+v5H  
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} iLQO .'{U  
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public String getSSiteURL() W|{!0
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{ f-^*p  
return sSiteURL; Uf_mwEE  
} 7#"y mE  
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public void setSSiteURL(String value) B^M L}$  
{ p\I3fI0i  
sSiteURL = value; U(+QrC:  
} ph)=:*A6&  
!1S!)#  
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public String getSFilePath()  })!-  
{ n9 bp0#K  
return sFilePath; G~_eBy  
} ;[lLFI  
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public void setSFilePath(String value) dC4`xUv  
{ 3#""`]9H  
sFilePath = value; `6Q+N=k~Z  
} aA*h*  
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public String getSFileName() )jwovS?V  
{ X,M
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return sFileName; ~D/Lo$K"  
} }j6|+  
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public void setSFileName(String value) -q)|I|y*7  
{ U3aM^
 
sFileName = value; j^Qk\(^#IV  
} /Re67cMQ*  
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public int getNSplitter() kSJ;kz,_  
{ ?TDmW8G}J  
return nSplitter; dhg($m  
} B\|^$z
2  
]LCL?zAzH!  
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public void setNSplitter(int nCount) _MQh<,Z8  
{ 9l[C&0w#\  
nSplitter = nCount; $Y$s*h_-/<  
} nJgN2Z  
} j$u  
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/* L`:V]p  
**Utility.java >)[W7h  
*/ 3<Z@!ft8  
package NetFox; 0aGauG[  
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public class Utility { fP;I{AiN~  
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public Utility() MD0d  
{ INCanE`+  
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} g p9;I*!  
a*,V\l|6  
//线程睡眠 2*-qEUl1  
public static void sleep(int nSecond) su60j^e*  
{ EcR[b@YI  
try{ t1#f*G5  
Thread.sleep(nSecond); k9y/.Mu  
} >FFp"%%  
catch(Exception e) 0!c/4^  
{ kmJ<AnK  
e.printStackTrace (); tsB}'+!v#  
} g]b%<DJ  
} ]3U|K .G  
/HSg
)  
//日志 DfOigLG*  
public static void log(String sMsg) :h0!giqoQ  
{ Qc 1mR\.5  
System.err.println(sMsg); % 5!Y#$:{o  
} sWq}/!@&  
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public static void log(int sMsg) $reQdN=~  
{ o}D7 $6  
System.err.println(sMsg); Ko0T[TNkh  
} Ej@N}r>X  
} C0>)WVCK  

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"LZv\c~v,%  
/* 3\B~`=*q/  
**TestMethod.java LKud'  
*/ !?B2OE  
package NetFox; @nj`T{*.  
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public class TestMethod { T< <N U"n  
61b<6r0o  
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public TestMethod() |L)qH"Eo  
{ ///xx/weblogic60b2_win.exe kgX"I ?>d  
try{ 0M}Ql5+h,  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 0NSCeq%;6q  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); rsK b9G  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Bo*Wm w  
fileFetch.start(); *u34~v16,  
} 4Gh%PUV#  
catch(Exception e){e.printStackTrace ();} !NhVPb,  
@jr$4pM?  
;4vx+>-  
} ?l 0WuU  
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public static void main(String[] args) jdD`C`w|,  
{ I]~UOl  
new TestMethod(); !;U}ax;AF  
} I"jub kI=Z  
} WODgG@w  
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