http断点续传简单实现（java)

/* "q9~C  
**SiteFileFetch.java L)kb (TH  
*/ so?pA@O
 
package NetFox; ;Ch+X$m9  
import java.io.*; p@cfY]<7  
import java.net.*; V_+}^  
l5ZADK4  
9:9N)cNvfX  
public class SiteFileFetch extends Thread { [|:
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SiteInfoBean siteInfoBean = null; //文件信息Bean #/n|@z'  
long[] nStartPos; //开始位置 *1|YLy  
long[] nEndPos; //结束位置 _dYf  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Lf,CxZL5  
long nFileLength; //文件长度 ?r -\%_J_(  
boolean bFirst = true; //是否第一次取文件 #Acon7Rp  
boolean bStop = false; //停止标志 L?=#*4t  
File tmpFile; //文件下载的临时信息 6)=](VmNL`  
DataOutputStream output; //输出到文件的输出流 ffmG~$Yh_  
8N=%X-R%  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） H$NP1^5!  
public SiteFileFetch(SiteInfoBean bean) throws IOException Gt^|+[gD  
{ Wphe%Of  
siteInfoBean = bean; ewb*?In  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ntrY =Y  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 8Zcol$XS'  
if(tmpFile.exists ()) n~1tm  
{ (l\a'3a.  
bFirst = false; }G>v]bV0V  
read_nPos(); Ez06:]Jd  
} c[(yU#@  
else /#-,R,Q  
{ o/t
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nStartPos = new long[bean.getNSplitter()]; C-s>1\I  
nEndPos = new long[bean.getNSplitter()]; .+{nA}Bc  
} EpRXjz  
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} MZCL:#  
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)/  
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public void run() 6@"Vqm|HD  
{ @IEI%vH  
//获得文件长度 >|l;*Kw,/P  
//分割文件 X4d Xm>*?=  
//实例FileSplitterFetch gbYLA a  
//启动FileSplitterFetch线程 >]>0KQfO  
//等待子线程返回 J}x>~?W  
try{ 4^ c!_K&&  
if(bFirst) x1|Da$2  
{ ;V|M3  
nFileLength = getFileSize(); ^7i^ \w0  
if(nFileLength == -1) $cRcap  
{ [Z#
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System.err.println("File Length is not known!"); Of1IdE6~  
} pBlRd{#fL  
else if(nFileLength == -2) (3e;"'
k  
{  5Waw?1GL  
System.err.println("File is not access!"); Wr]O  
} 4a\n4KO X  
else xCR; K]!  
{ ]XmQ]Yit  
for(int i=0;i<nStartPos.length;i++) VYL@RL'  
{ 6P0y-%[Gk  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); cDfx)sL  
} LiiK3!^i  
for(int i=0;i<nEndPos.length-1;i++) 4st~3,lR$  
{ t{+M|Y  
nEndPos = nStartPos[i+1]; o)0C-yO0qf  
} 77+|#<J  
nEndPos[nEndPos.length-1] = nFileLength; /uK)rG F  
} D~cW ]2  
} =YWT|%^uX  
A{4Dzm!  
*6NO-T; -  
//启动子线程 A;odVaH7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; S$S_nNq

 
for(int i=0;i<nStartPos.length;i++) C>AcK#-x,{  
{ Z+Kv+GmqH  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K|`+C1!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), VMaS;)0f@  
nStartPos,nEndPos,i); (F/HU"C  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6_W<hevI  
fileSplitterFetch.start(); smQ4CLJ  
} >NJjS8f5  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2K3MAd{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); J cP~-cp  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 7rH'1U  
nEndPos = " + nFileLength); [:Be[pLC
 
// fileSplitterFetch[nPos.length-1].start(); %_>Tcm=  
1#/6r :  
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//等待子线程结束 +H41]W6  
//int count = 0; ,Qat  
//是否结束while循环 DNmb[  
boolean breakWhile = false; $"/UK3|d  
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while(!bStop) JRD8Lz]Q3  
{ UMT\Q6p  
write_nPos(); Cy`26[E$S  
Utility.sleep(500); D)y{{g*Lnm  
breakWhile = true; v}Z9+ yRC2  
[w,(EE   
+yGY785b  
for(int i=0;i<nStartPos.length;i++) =D{B}=D\IM  
{ }I\-HP8!gv  
if(!fileSplitterFetch.bDownOver) :=y0'f V(@  
{ Dzo{PstM%  
breakWhile = false; 'c#IMlv  
break; mU>&ql?e  
} o\&~CW~@~  
} `(3SfQ-  
if(breakWhile) ooY\t +  
break; =PV/`I_h  
wcwQjHwd  
e]>/H8  
//count++; e$HQuA~Q;  
//if(count>4) kQy&I3  
// siteStop(); CF\R<rF<VS  
} |P>|D+
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System.err.println("文件下载结束！"); AfN&n= d K  
} ,6DD=w0r  
catch(Exception e){e.printStackTrace ();} }~rcrm.   
} /oFc03d  
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//获得文件长度 $Y6 3!*  
public long getFileSize() V`by*s  
{ #XcU{5Qm5  
int nFileLength = -1; -/zp&*0gcx  
try{ <>]1Y$^Y
 
URL url = new URL(siteInfoBean.getSSiteURL()); pL! a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); IJ0#iA. T  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7RD$=?oO'  
RE 9nU%!  
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int responseCode=httpConnection.getResponseCode(); Gbn4
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if(responseCode>=400) 3524m#4&@  
{ Qo.Uqz.C  
processErrorCode(responseCode); vGMJ^q  
return -2; //-2 represent access is error _PV*lK=  
} mW~
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String sHeader; D;jK/2  
#MglHQO+  
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for(int i=1;;i++) @ ICbKg:  
{ 0Qp[\ia  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); |0kXCq  
//Utility.log(in.readLine()); Y87XLvig}  
sHeader=httpConnection.getHeaderFieldKey(i); Pr`s0J%m  
if(sHeader!=null) \"'
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{ z{|LQt6q  
if(sHeader.equals("Content-Length")) >ukQ, CE~  
{ (')(d HHW  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8aZ$5^z  
break; h8jB=e, H  
} +}U2@03I  
} ~,gLplpG0  
else Hx
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break; ;SKcbws  
} LQqfi ~  
} =T4u":#N;  
catch(IOException e){e.printStackTrace ();}
]IS;\~  
catch(Exception e){e.printStackTrace ();} 1[s0Lz  
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Utility.log(nFileLength); @cIgxp  
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return nFileLength; 6{.J:S9n   
} pv&^D,H,  
_f|/*. @Q  
,#d[ad<  
//保存下载信息（文件指针位置） `eC+% O  
private void write_nPos() +ubnx{VC  
{ jgq{p
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try{ # $~ oe"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ~RInN+N#  
output.writeInt(nStartPos.length); @VK6JjIq  
for(int i=0;i<nStartPos.length;i++) AkA!:!l  
{ @1bH}QS  
// output.writeLong(nPos); OJpj}R  
output.writeLong(fileSplitterFetch.nStartPos); 'E-FO_N  
output.writeLong(fileSplitterFetch.nEndPos); ^C7C$TZS  
} G6Nb{m  
output.close(); NAJVr}4f  
} 7Cy<mS  
catch(IOException e){e.printStackTrace ();} }Eh*xOta  
catch(Exception e){e.printStackTrace ();} #wjH4DT
 
} ^N-'xy  
#\ #3r  
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//读取保存的下载信息（文件指针位置） \|t{e8}  
private void read_nPos() f4"4ZVcr  
{ k':s =IXW  
try{ 6
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9Ejyg*  
int nCount = input.readInt();
]Ik%#l.G_  
nStartPos = new long[nCount]; R=M!e<'  
nEndPos = new long[nCount]; "hPCQp`Tj  
for(int i=0;i<nStartPos.length;i++) <lj\#'G3  
{ R ]P;sk5  
nStartPos = input.readLong(); >1ZJ{se  
nEndPos = input.readLong(); 6P*O&1hv  
} sS9%3i/>  
input.close(); TzKK;(GX  
} wkBL=a  
catch(IOException e){e.printStackTrace ();} 3?`"  
catch(Exception e){e.printStackTrace ();} N4wA#
\-  
} =~jAoOC@  
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private void processErrorCode(int nErrorCode) d~Mg vh'  
{ i_
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System.err.println("Error Code : " + nErrorCode); 7
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} JJnYOau  
j
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@Y-TOCadT  
//停止文件下载 S_\ F
 
public void siteStop() -5k2j^r;  
{ 2d`c!  
bStop = true; @;Y~frT  
for(int i=0;i<nStartPos.length;i++) Hg+ F^2<y  
fileSplitterFetch.splitterStop(); 2f,2rW^i  
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} .=<$S#x^Hb  
} E FY@Y
[  
//负责部分文件的抓取 o8ppMM8_R[  
**FileSplitterFetch.java XUSvhr$|  
*/ ^E,1V5  
package NetFox; O3qM1-k}S  
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dR+1aY;  
import java.io.*; 4!%F\c46  
import java.net.*; B42sb_  
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public class FileSplitterFetch extends Thread { +iA=y=;blH  
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; Lql_1  
String sURL; //File URL *e/K:k  
long nStartPos; //File Snippet Start Position T3pdx~66  
long nEndPos; //File Snippet End Position |B^G:7c  
int nThreadID; //Thread's ID Vmi{X b]<  
boolean bDownOver = false; //Downing is over ~uj;qq  
boolean bStop = false; //Stop identical ln<]-)&C  
FileAccessI fileAccessI = null; //File Access interface 6rX_-Mm6w  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Uyx&E?SlEq  
{ zp4W'8  
this.sURL = sURL; *b)Q5dw@1  
this.nStartPos = nStart; x0Z5zV9  
this.nEndPos = nEnd; *#&*`iJ(  
nThreadID = id; YZE.@Rz  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~?U*6P)o  
} 0X9Y~TM%  
SEd5)0X^  
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public void run() CxF-Z7 '  
{ ~cqryr9  
while(nStartPos < nEndPos && !bStop) P Sx304  
{ $nPAm6mH  
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try{ Q8qz*v]{  
URL url = new URL(sURL); uk7'K 0j  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); m*e YC  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^^Jnv{)  
String sProperty = "bytes="+nStartPos+"-"; EKZVF`L  
httpConnection.setRequestProperty("RANGE",sProperty); e/s(ojDW  
Utility.log(sProperty); ]%dnKP~  
:}q\tNY<  
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InputStream input = httpConnection.getInputStream(); pq!%?m]  
//logResponseHead(httpConnection); RBGX_v?  
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byte[] b = new byte[1024]; L%cVykWY"  
int nRead; vqNsZ 8|`  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5#2F1NX  
{ jC, FG'P  
nStartPos += fileAccessI.write(b,0,nRead); ,mFsM!|  
//if(nThreadID == 1) csQfic  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xWX*tJ4  
} eon!CE0  
b,^*mx=  
;<wS+4,  
Utility.log("Thread " + nThreadID + " is over!"); mpay^.(%  
bDownOver = true; -J0WUN$2*  
//nPos = fileAccessI.write (b,0,nRead); ^TFs;|..  
} d- E4~)Qy  
catch(Exception e){e.printStackTrace ();} 9NpD!A&64<  
} F%/h*  
} m7qqY  
}5 9U}@xC  
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//打印回应的头信息 $u9]yiY.{  
public void logResponseHead(HttpURLConnection con) s0W2?!>)  
{ O#kq^C}  
for(int i=1;;i++) =VP=|g  
{ 2+"r~#K*  
String header=con.getHeaderFieldKey(i); JXU2CyMY  
if(header!=null) 8E^@yZo{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); \wav?;z  
Utility.log(header+" : "+con.getHeaderField(header)); 1|QvN1?  
else 5g ;ac~g  
break;
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} Q<"[C 1Lj  
} CAc %f9!3  
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public void splitterStop() v3RcwySk  
{ V5rp.~  
bStop = true; PX,rWkOce  
} v."Dnl  
9.+/~$Ht  
,LYFEq_  
} (9RslvKL  
?Dsm~bkX[  
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/* F?4(5 K  
**FileAccess.java kCP$I732  
*//文件访问(定位，写) m <k!^jp  
package NetFox; RDQ^dui
  
import java.io.*; 6f%DpJ:$U  
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public class FileAccessI implements Serializable{ j|(Z#3J  
c6AWn>H
 
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 xi
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RandomAccessFile oSavedFile; ^4$'KIq  
long nPos; cPF<D$B  
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public FileAccessI() throws IOException ~oD8Rnf  
{ SW?p?<  
this("",0); E l&h;N  
} P`SnavQBt  
/!&R9!6 :  
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public FileAccessI(String sName,long nPos) throws IOException X" R<J#4  
{ mxG]kqi  
oSavedFile = new RandomAccessFile(sName,"rw"); /!xF?OmVd  
this.nPos = nPos; +C{p%`<  
oSavedFile.seek(nPos); gUax'^w;V;  
} U8QX46Br  
V6a``i]  
Q5+_u/  
public synchronized int write(byte[] b,int nStart,int nLen) <,%:   
{ `iG,H[t+j  
int n = -1; VM=+afY5M  
try{ oR#:NtX
@  
oSavedFile.write(b,nStart,nLen); '\DSTr:N  
n = nLen; _7)F ?  
} %b!-~ Y.  
catch(IOException e) '3(l-nPiG^  
{ ,TC;{ $O5  
e.printStackTrace (); e;95a  
} xK%=  
$0Yh!L?\  
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return n; t!;/Z6\Pb  
} RMYP"  
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$ChK]v 6C  
} }-<zWI{p  
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]> !<G8=N  
/* h1"zV6U  
**SiteInfoBean.java J{"kw1Lu  
*/ b!>\2DlyJ  
package NetFox; .w? .ib(  
3TuC+'`G  
\k8rxW  
public class SiteInfoBean { keAcKhj  
}E^S]hdvz  
X=X\F@V:u  
private String sSiteURL; //Site's URL $ItF])Bj5N  
private String sFilePath; //Saved File's Path HL{$ ^l#v  
private String sFileName; //Saved File's Name q 2?X"!  
private int nSplitter; //Count of Splited Downloading File 6vzk\n  
\>/M .2  
HRa@  
public SiteInfoBean() rp
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{//nSplitter的缺省值为5  $6>?;  
//default value of nSplitter is 5 6gO9 MQY  
this("","","",5); GJ(d
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} CZ{k@z
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`(4pu6uT  
XR+3j/zEQ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) +FFG#6e  
{ 4jmK].  
sSiteURL= sURL; S5=Udd"  
sFilePath = sPath; 4N?v  
sFileName = sName; rJfqA@  
this.nSplitter = nSpiltter; *gsAn<  
{y^3> 7  
=d;Vk  
} !cEG}(|h  
$A\m>*@  
8%{q%+  
public String getSSiteURL() !UBO_X%dz  
{ V1=*z  
return sSiteURL; =H]F`[B=  
} vxlOh.a|/L  
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public void setSSiteURL(String value) v[k5.\No  
{ m@xi0t  
sSiteURL = value; oUDVy_k  
} |VH!)vD  
!|wzf+V  
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public String getSFilePath() |?m` xO  
{ tV;%J4E'  
return sFilePath; HaNboYW_K  
} /)|X.D  
v@ C,RP9  
7()?C}Ni-  
public void setSFilePath(String value) h+UnZfm  
{ jh ez  
sFilePath = value; >%b\yl%0  
} SqPtWEq@P  
Sq]
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jB$SUO`*  
public String getSFileName() g;p)n  
{ H3/c
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return sFileName; 1cN')"  
} VAQ)Hc]  
h=VqxGC&  
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public void setSFileName(String value) 4)-)#`K  
{ nY-*
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sFileName = value; JyBp-ii  
} FVWfDQ$&v  
[`fI:
ao|  
&vUq}r%P  
public int getNSplitter() 'JmBh@A  
{ qojXrSb"y  
return nSplitter; w; TkkDH  
} NC23Z0y  

+JdZPb  
oY9FK{  
public void setNSplitter(int nCount) GY!C|7kN  
{ !|{IVm/J  
nSplitter = nCount; mNmUUj9z  
} {aq9i  
} :> -1'HC  
nL`9l1  
I`B'1"{  
/* iDb;_?  
**Utility.java xp \S2@<  
*/ u</8w&!  
package NetFox; I+?hG6NM  
rs8\)\z  
B&KL2&Z~Pq  
public class Utility { {")\0|2\x  
GlYly5F  
'?Bg;Z'L%  
public Utility() )najO*n  
{ y=N"=Z  
,{}#8r`+*  
}7/e8 O2  
} UGKaOol.  
?bX  
//线程睡眠 ~5aE2w0K
 
public static void sleep(int nSecond) l
J  
{ HOW7cV'X  
try{ o \L!(hm  
Thread.sleep(nSecond); S>:,
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} =]>%t]  
catch(Exception e) 4*H"Z(HP  
{ >%%=0!,yX  
e.printStackTrace (); X T>('qy  
} *> 3Qd7  
} o+?@5zw-&  
htJuGfDx1  
//日志 4
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public static void log(String sMsg) =7/-i  
{ = 1|"-  
System.err.println(sMsg); [Eq<":)  
} %_)zWlN  
|"7Pv skT  
S3\jcgrS  
public static void log(int sMsg) Fz"ff4Bx [  
{ f05d ;  
System.err.println(sMsg); zmFws-+A  
} 4MvC]_&  
} Ej
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h[Tk;h  
@'jfKW  
/*  -;c  
**TestMethod.java )C]x?R([m  
*/ <e"J4gZf&  
package NetFox; c
[(Pg%  
n~r 9!m$<  
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public class TestMethod { N+Sq}hI  
s;.=5wcvi?  
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public TestMethod() $Xf(^K  
{ ///xx/weblogic60b2_win.exe G2Qjoe`Uc  
try{ DZ`k[Z.VZ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %efGt6&  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); " ~Q*XN2  
SiteFileFetch fileFetch = new SiteFileFetch(bean); d0UZ+ RR#  
fileFetch.start(); knHv?#  
} ^X
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catch(Exception e){e.printStackTrace ();} &d^=siL  
%$X\"  
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} ^X?D#\  
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g:~+Pe  
public static void main(String[] args) @6MAX"  
{ W kkxU.xXE  
new TestMethod(); mb1IQ &  
} xy^1US,L1  
} vOT*iax0  
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