http断点续传简单实现（java)

/* Fo=Icvo  
**SiteFileFetch.java {~_X-g5|]  
*/ 2w>WS#  
package NetFox; PTWP7A[  
import java.io.*; [fiB!G]?  
import java.net.*; !1$QNx
gi  
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public class SiteFileFetch extends Thread { 7xTgG!>v  
\  $;E,  
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SiteInfoBean siteInfoBean = null; //文件信息Bean w=Ac/12  
long[] nStartPos; //开始位置 <u]M):b3  
long[] nEndPos; //结束位置 ?`bi8 Ck  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 N DZ :`D  
long nFileLength; //文件长度 1@rI4U@D  
boolean bFirst = true; //是否第一次取文件 v;AsV`g  
boolean bStop = false; //停止标志 }:<`L\8q\  
File tmpFile; //文件下载的临时信息 4$#nciAe  
DataOutputStream output; //输出到文件的输出流 m-Q!V+XQp  
it.Lh'N;T  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） UmUw>+A  
public SiteFileFetch(SiteInfoBean bean) throws IOException SR)G!9z_/  
{ Yj3j?.JJk  
siteInfoBean = bean; /'k4NXnW3  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ebK/cPa8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); OC34@YUj[  
if(tmpFile.exists ()) (KtuikJ32^  
{ 2fFZ70
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bFirst = false; n}/?nP\%  
read_nPos(); Ezsb'cUa(  
} >-J%=P  
else }K':tX?  
{ wCw-EGLR  
nStartPos = new long[bean.getNSplitter()]; %Xc50n2Z  
nEndPos = new long[bean.getNSplitter()]; w.Cw)#N  
} qWX%[i%  
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b* k=
  
} N3dS%F,_  
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public void run() J<hqF4z  
{ :/UO3 c(  
//获得文件长度 OH.^m6Z  
//分割文件 W%&t[_21  
//实例FileSplitterFetch WzG]9$v &  
//启动FileSplitterFetch线程 fy9mS  
//等待子线程返回 _3@[S F  
try{ yvR3
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if(bFirst) R9XISsM^  
{ WK$75G,  
nFileLength = getFileSize(); r
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if(nFileLength == -1) 7q\&  
{ ]nPfIBoS  
System.err.println("File Length is not known!");  dpG l  
} >=Bl/0YH  
else if(nFileLength == -2) -KV)1kET  
{ mV!Ia-k  
System.err.println("File is not access!"); (5CdA1|  
} 6d~[j<@2  
else QA|87alh  
{ TQ`s&8"P  
for(int i=0;i<nStartPos.length;i++) 1i=lJmr  
{ )(b,v/:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); s/Ne,v  
} QFekj@  
for(int i=0;i<nEndPos.length-1;i++) XBx
&&  
{ pHKcKqB*13  
nEndPos = nStartPos[i+1]; <[.{aj]QV  
} 3DjlX*  
nEndPos[nEndPos.length-1] = nFileLength; 0\tV@ 6p2=  
} %!P^se  
} rtM29~c>@  
m\*;Fx  
<MK4
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//启动子线程 +vf~s^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ul(pp+%S  
for(int i=0;i<nStartPos.length;i++) 7`xeuK  
{ )<ig6b%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), CgT5sk}
 
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), _*iy *:(o  
nStartPos,nEndPos,i); <S[]VXy  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BjX*Gm6l  
fileSplitterFetch.start(); unX mMSz(
 
} ZG(.Q:1  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <TN+-)H6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); lZ,w#sqbY  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", X|&v]mJ  
nEndPos = " + nFileLength); ,c]<Yu  
// fileSplitterFetch[nPos.length-1].start(); Rtywi}VV2  
N>V\  
,zF^^,lO7  
//等待子线程结束 ?uAq goCl  
//int count = 0; #(pY~\  
//是否结束while循环 K92nh/}y  
boolean breakWhile = false; wWYo\WH'  
itYTV?bd  
]v2%hX  
while(!bStop) *ggai?  
{ . E8Gj'yO  
write_nPos(); xg(*j[ff3  
Utility.sleep(500); op8[8pt%  
breakWhile = true; Mi^/`1  
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+HDfEo T  
for(int i=0;i<nStartPos.length;i++) =Ju%3ptH0  
{ q%S^3C&  
if(!fileSplitterFetch.bDownOver) aHR+
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{ evSr?ys  
breakWhile = false; 6uS;H]nd<  
break; ,vDSY N6  
} z(!K8 T  
} ?3#L?Cq  
if(breakWhile) }1kZF{KD<[  
break; } *:H\GL  
}Y~<|vZ  
<nvzNXql  
//count++; \+Nn>wW.  
//if(count>4) BbIg]E/G  
// siteStop(); `; +UWdAR  
} 99GK6}~TGm  
#1)#W6 h\  
4`Ib wg6"B  
System.err.println("文件下载结束！"); V=d~}PJ>  
} `G'Z,P-a  
catch(Exception e){e.printStackTrace ();} @@W-]SR  
} SX)o0v+  
b[U;P=;=  
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//获得文件长度 0<[g7BbR  
public long getFileSize() d~abWBgC`  
{ )+ (GE  
int nFileLength = -1; gmUX 2x(  
try{ W0+m A  
URL url = new URL(siteInfoBean.getSSiteURL()); Vi=u}(*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); pgw_F  
httpConnection.setRequestProperty("User-Agent","NetFox"); L3;cAb/  
bHRRgR`,  
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int responseCode=httpConnection.getResponseCode(); xL
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if(responseCode>=400) dy.U;  
{ .Lm0$o*`  
processErrorCode(responseCode); o_C]O"  
return -2; //-2 represent access is error cI\&&<>SlG  
} wiP )"g.t  
"'3QKeM1  
c#zx" ,K  
String sHeader; 4+B&/}FDLo  
_T.T[%-&=  
;9;jUQ]MyG  
for(int i=1;;i++) PfN[)s4F{R  
{ `f<&=_,xfH  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 3f-J%!aH  
//Utility.log(in.readLine()); U|~I
JU3-  
sHeader=httpConnection.getHeaderFieldKey(i); g1{2E<b5  
if(sHeader!=null) rM0Idc.$&&  
{ Pi
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if(sHeader.equals("Content-Length")) $D
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{ X?aj0# Q  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?_`X8Ok  
break; G'T:l("l  
} "Z]z9(  
} @5j3
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else HSj=g}r  
break; Gp0yRT.  
} 
!j%#7  
} W`F?j-4  
catch(IOException e){e.printStackTrace ();} pGcijD  
catch(Exception e){e.printStackTrace ();} 888"X
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Utility.log(nFileLength); :Aa5,{v_  
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return nFileLength; 6KE?@3;Om  
} gxc8O).5vY  
"ph[)/u;  
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//保存下载信息（文件指针位置） rqTsKrLe  
private void write_nPos() F;8Uvj  
{ x31Jl{x8\?  
try{ o(stXa  
output = new DataOutputStream(new FileOutputStream(tmpFile)); J+uz{  
output.writeInt(nStartPos.length); (R]b'3,E$  
for(int i=0;i<nStartPos.length;i++) n{"e8vQx
 
{ u>*d^[zS  
// output.writeLong(nPos); -ZH6*7!  
output.writeLong(fileSplitterFetch.nStartPos); HX#$ ^@Q(  
output.writeLong(fileSplitterFetch.nEndPos); ,CIsZ1[VS  
} a9!.e rM
 
output.close(); v[]&yD  
} MDauHtF,  
catch(IOException e){e.printStackTrace ();} h\/T b8  
catch(Exception e){e.printStackTrace ();} AP9>_0=  
} 1T 8|>2m 3  
"?>hQM1R  
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//读取保存的下载信息（文件指针位置） o&R
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private void read_nPos() 9'0v]ar  
{ cH`ziZ<&m1  
try{ UIo jXR<  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )Ec /5=A  
int nCount = input.readInt(); a{\<L/\  
nStartPos = new long[nCount]; mJ'5!G  
nEndPos = new long[nCount]; RYV:?=D7s  
for(int i=0;i<nStartPos.length;i++) ]6].l$%z#  
{ _i2guhRs*Q  
nStartPos = input.readLong(); .zo>,*:t  
nEndPos = input.readLong(); W3A9uk6  
} % U|4%P  
input.close(); C zxF  
} yDw#V`Y^M  
catch(IOException e){e.printStackTrace ();} ;:aCZ8e  
catch(Exception e){e.printStackTrace ();} #@:GLmD%  
} j4+kL4M@H  
(%)<jg
1  
<P_B|Y4N/  
private void processErrorCode(int nErrorCode) f,VJfY?#  
{ ?sclOOh  
System.err.println("Error Code : " + nErrorCode); z4rg.ai  
} P( 1Z  
;v m$F251  
F/:Jp3@  
//停止文件下载 S8Yti  
public void siteStop() M,g
$  
{ EttQ<z_T  
bStop = true; ;mwU>l,4  
for(int i=0;i<nStartPos.length;i++) -J^t#R^$`  
fileSplitterFetch.splitterStop(); s!?T$@a=  
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} z K6'wL!!I  
} }TG=ZVi  
//负责部分文件的抓取 !h>aP4ofT  
**FileSplitterFetch.java sEx`9_oZ  
*/ =6xxZy[  
package NetFox; wY*tq{7  
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import java.io.*; dPmNX-'7  
import java.net.*; %<h+_(\
h  
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public class FileSplitterFetch extends Thread { Q6hWHfS  
;` !j~  
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String sURL; //File URL 1{?5/F \ +  
long nStartPos; //File Snippet Start Position ^ ^k]2oG  
long nEndPos; //File Snippet End Position %ql2 XAY  
int nThreadID; //Thread's ID ,2]a<0m  
boolean bDownOver = false; //Downing is over Qn`Fq,uvL  
boolean bStop = false; //Stop identical v|wO qS  
FileAccessI fileAccessI = null; //File Access interface gJ?Vk<hp  
M"E7=J  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException c3C<P  
{ MXrh[QCU)  
this.sURL = sURL; W*9*^  
this.nStartPos = nStart; >=d%t6%(  
this.nEndPos = nEnd; *d&+?!  
nThreadID = id; M{O
8iq[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 m!Fx#  
} W6jdS;3  
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public void run() M6H#Y2!ZbC  
{ ,L$,d  
while(nStartPos < nEndPos && !bStop) Y(6p&I  
{ 9K4Jg]?  
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try{ p>= b|Qy|  
URL url = new URL(sURL); X*e<g=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;0-Y),  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3oMhsQz~z  
String sProperty = "bytes="+nStartPos+"-"; dr]Pns9  
httpConnection.setRequestProperty("RANGE",sProperty); S(Q=
2Y  
Utility.log(sProperty); Qb?eA  
st wxF?\NS  
[6f(3|"  
InputStream input = httpConnection.getInputStream(); {R}Kt;L:Ut  
//logResponseHead(httpConnection); j S<."a/n  
W
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byte[] b = new byte[1024]; g @qrVQv  
int nRead; h4tAaPcS+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) LuvRxmQ`  
{ @aUQy;  
nStartPos += fileAccessI.write(b,0,nRead); E{xcu9  
//if(nThreadID == 1) /eY}0q%  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); UpS7>c7s  
} ^(~%'f  
>WmTM0  
8 EUc 6  
Utility.log("Thread " + nThreadID + " is over!"); Mh8s@g  
bDownOver = true; k.!m-5E  
//nPos = fileAccessI.write (b,0,nRead); `,$PRN"]  
} o((!3H{D  
catch(Exception e){e.printStackTrace ();} y-lBaTE9  
} dQJ)0!B  
} ")D5ulb\  
89\DS!\x9  
'oS= d  
//打印回应的头信息 l9#@4Os  
public void logResponseHead(HttpURLConnection con) 4N8(WI"4S  
{ N'~l,{  
for(int i=1;;i++) E@_]L<Z  
{ `]j:''K  
String header=con.getHeaderFieldKey(i); ~ ^*;#[<  
if(header!=null) nj
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); .^V9XN{'a  
Utility.log(header+" : "+con.getHeaderField(header)); l#fwNM/F  
else tFu"h1  
break; nWFU8u%  
} 6D/K=-  
} Q|(G -  
m#`1.5%  
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public void splitterStop() v`Yj)  
{ 5DmW5w'p  
bStop = true; {3eg4j.Z  
} ph>0?Z =bn  
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X{ f#kB]w  
} &9F(C
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/* K(}g!iT)~  
**FileAccess.java )6*)u/x:  
*//文件访问(定位，写) bE6bx6=u  
package NetFox; 'J_`
CS  
import java.io.*; $d5}OI"g  
nd,2EX<bE  
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public class FileAccessI implements Serializable{ .> 5[;  
GBYwS{4  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ):7mK03J  
RandomAccessFile oSavedFile; 'q\[aKEX=  
long nPos; \k
.W F|~  
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rmJ`^6V  
public FileAccessI() throws IOException NM+(ss'  
{ >>%E?'9A  
this("",0); 3gs!ojG  
} `Jn2(+  
y&6 pc  
(D2N_l(`<  
public FileAccessI(String sName,long nPos) throws IOException .O6(QI*  
{ %/w%A:y#&  
oSavedFile = new RandomAccessFile(sName,"rw"); HpIWH*  
this.nPos = nPos; =fK6P6'B  
oSavedFile.seek(nPos); yR1v3D4E  
} d-`z1'  
::sk)  
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public synchronized int write(byte[] b,int nStart,int nLen) #Q@~TW  
{ 7mA:~-.u  
int n = -1; r<5i  
try{ Y|cj&<o  
oSavedFile.write(b,nStart,nLen); gN.n_!  
n = nLen; 47!k!cHa  
} uU/'oZ?  
catch(IOException e) E7 P'}  
{ d~#:t~ $,  
e.printStackTrace (); ;k (M4?  
} A,4Z{f83  
-+y3~^EYm,  
22@w:  
return n; n;e.N:p  
} sFw;P`  
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} }U@(S>,%  
9k;%R5(  
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/* w+gPU1|(r  
**SiteInfoBean.java KJ cuZ."wX  
*/ FD/=uIXH2  
package NetFox; @ \*Zq  
IlZ$Jd  
!md1~g$rN  
public class SiteInfoBean { 6#kmV  
"'~&D/7  
5DL(#9F8b9  
private String sSiteURL; //Site's URL .*
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private String sFilePath; //Saved File's Path &M7AM"9
 
private String sFileName; //Saved File's Name v9"03=h  
private int nSplitter; //Count of Splited Downloading File +LF`ZXe8l  
@T%8EiV  
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public SiteInfoBean() ~uu{ v')  
{//nSplitter的缺省值为5 ^/)%s3  
//default value of nSplitter is 5 <xUX&J=;  
this("","","",5); NIG* }[}P  
} L[tq@[(IJ  
lX64IvG8+o  

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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 'u3,+guz  
{ t**MthnW  
sSiteURL= sURL; R%6KxN)+@  
sFilePath = sPath; GHpP *x  
sFileName = sName; 6|QIzs<Z-X  
this.nSplitter = nSpiltter; Bo0f`EC I  
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%7 $X *  
} j
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?hKpJA'%  
public String getSSiteURL() ^*b11/7  
{ 0~BZh%s< (  
return sSiteURL; XA\wZV |{  
} ?u>A2Vc!  
%*OQH?pyx}  
0zE(:K  
public void setSSiteURL(String value) Iz8gZ:rd0  
{ 2E0oLl[  
sSiteURL = value; a1z*Z/!5  
} 3x)jab  
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public String getSFilePath() \7G.anY  
{ 5%w08  
return sFilePath; yC[Q-P*rG  
} d 9]zB-A  
9yp'-RKjw  
4P?@N
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public void setSFilePath(String value)  Y+Cv9U0  
{ HqXS-TG  
sFilePath = value; $V;0z~&!'  
} D{6<,#P{w  
M=4`^.Ocm  
T!-ly7-`  
public String getSFileName() w[#*f?at~  
{ >3&9Wbv>  
return sFileName; f1 `E-  
} JG@Zb}b  
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?N&s.  
public void setSFileName(String value) [`'K.-?#  
{ w,LB  
sFileName = value; c
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} tNljv >vI  
])?
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ZUS06#t}  
public int getNSplitter() m}'!W`<  
{ ppnl bL^*  
return nSplitter; P?+ VR=t  
} ;<#=|eD2  
0a:@DOzT  
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public void setNSplitter(int nCount) XRi37|p  
{ ) .W0}  
nSplitter = nCount; sLf~o"yb  
} o_&Qb^W  
} |k]fY*z(  
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/* 1V-sibE  
**Utility.java eE@7AM  
*/ j|LOg  
package NetFox; 5:%`&B\  
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public class Utility { sU/vXweky"  
NMESGNa)z  
@>`qfy?  
public Utility() fYlqaO4[  
{ +@~e9ZG%a  
dw%g9DT  
l0eh}d  
} k=9k4l  
2yVQqwQm  
//线程睡眠 (V0KmNCW`  
public static void sleep(int nSecond) t:n$9WB)  
{ ,fvhP $n  
try{ s1p<F,  
Thread.sleep(nSecond); U5[r&Y D  
} `t+;[G>ZE  
catch(Exception e) FBa-gm<9  
{ L$^
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e.printStackTrace (); >J{e_C2ZS  
} zICrp  
} rVwW%&  
@/xdWN!,  
//日志 ,m
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public static void log(String sMsg) <DhuY/o  
{ 2\CZ"a#[  
System.err.println(sMsg); ]PB95%  
} S$/SFB$)~W  
60l!3o"p!  
MHS|gR.c  
public static void log(int sMsg) dRUmC H  
{ HahA} Q  
System.err.println(sMsg); ={50>WXE  
} P>Ru  
} ;8w CQ  
N!<X%Ym  
6\? 2=dNX  
/* lU.aDmy<  
**TestMethod.java |(uo@-U  
*/ V-18~+F~"a  
package NetFox; n!U1cB{  
6n H'NNS:J  
s\(@f4p  
public class TestMethod { -c#vWuLl  
c_Iq!MH  
 ~;uU{TT  
public TestMethod() B^.:dn  
{ ///xx/weblogic60b2_win.exe }S{VR(i`J  
try{ lYU?j|n  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); df/7u}>9  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); pL: r\Y:R  
SiteFileFetch fileFetch = new SiteFileFetch(bean); <3x:nH @  
fileFetch.start(); a..LbQQ  
} 9{%/I   
catch(Exception e){e.printStackTrace ();} [-^xw1:  
=-avzuy#  
WfQZ7e  
} oo1h"[  
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c/%GfB[w0  
public static void main(String[] args) n{=Ot^ ";  
{ /< Dtu UM  
new TestMethod(); ?y,KN}s_  
} k<RaC=   
} `:d\L H  
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