http断点续传简单实现（java)

/* p[;@9!t  
**SiteFileFetch.java aY DM)b}  
*/ pr1kYMrqri  
package NetFox; \FnR'ne  
import java.io.*; nj-LG!"a  
import java.net.*; 1KjzKFnb  
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public class SiteFileFetch extends Thread { lg{M\ +  
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4  
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SiteInfoBean siteInfoBean = null; //文件信息Bean PtGFLM9R  
long[] nStartPos; //开始位置 ke)<E98DC  
long[] nEndPos; //结束位置 ,pUB[w\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 N{6-a  
long nFileLength; //文件长度 o :j'd  
boolean bFirst = true; //是否第一次取文件 >D_)z/v?"  
boolean bStop = false; //停止标志 $2a_!/  
File tmpFile; //文件下载的临时信息 
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DataOutputStream output; //输出到文件的输出流 j!@,r^(  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） F'@9kdp  
public SiteFileFetch(SiteInfoBean bean) throws IOException j@4]0o  
{ S8C}C
#  
siteInfoBean = bean; E/gfX   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); n8FIxl&u  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); j{/5i`5m  
if(tmpFile.exists ()) V}FH5z |  
{ r&~]6 U  
bFirst = false; <)"2rxX&5  
read_nPos(); ?!3u?Kd  
} O8-Z >;  
else ^KV:.up6  
{ lXD=uRCI  
nStartPos = new long[bean.getNSplitter()]; 2Tv W 6  
nEndPos = new long[bean.getNSplitter()]; $F]*B `  
} g'EPdE  
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s~c cx"HH  
} KbH|'/w  
8
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public void run() G)gb5VW k  
{ -oY8]HrXfK  
//获得文件长度 o<5+v^mt#  
//分割文件 'L^M"f^I  
//实例FileSplitterFetch &M=15 uCK  
//启动FileSplitterFetch线程 'vKae  
//等待子线程返回 J8[aVG  
try{ +KOhDtLMG  
if(bFirst) X9rao n  
{ KXBTJ&  
nFileLength = getFileSize(); _<?z-K_;I  
if(nFileLength == -1) T^ #1T$  
{ L:.Rv0XT  
System.err.println("File Length is not known!"); 6H0aHCM  
} V8Z@y&ny  
else if(nFileLength == -2) ZbH_h]1$D  
{ V=Z%y$1Bc  
System.err.println("File is not access!"); iaQFVROu  
} ^__P;Gr`  
else QJI]@3 Y  
{ EEvi_Z932  
for(int i=0;i<nStartPos.length;i++) HaF&ooI5+  
{ !lp7}[k<y  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); q35=_'\W  
} Vq^b_^  
for(int i=0;i<nEndPos.length-1;i++) yP34h*0B  
{ /)4Q%Zp  
nEndPos = nStartPos[i+1]; {&FOa'bP  
} @2>c
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nEndPos[nEndPos.length-1] = nFileLength; ]#rNz"  
} 1\
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} AU;Iif6  
x@x5|8:ga  
%Kh}6   
//启动子线程 @}'?o_/C  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @k/|%%uP  
for(int i=0;i<nStartPos.length;i++) I,r0K]  
{ .fK~IKA  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8mO_dQ
 
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), c#@L~<  
nStartPos,nEndPos,i); \t? ;p-+ta  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r/QI-Cf&  
fileSplitterFetch.start(); I}awembw g  
} v(,YqT>q@U  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T ^/\Rr  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "J`#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", P75@Yu(  
nEndPos = " + nFileLength); gmOP8.g  
// fileSplitterFetch[nPos.length-1].start(); ~x J#NC+  
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1`Uu;m
z  
//等待子线程结束 A^4#6],%v  
//int count = 0; s1X?]A  
//是否结束while循环
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boolean breakWhile = false; X& XD2o"rt  
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while(!bStop) tnq ZlS  
{ g
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write_nPos(); T6\d]  
Utility.sleep(500); w~n+hhMF  
breakWhile = true; }xgs]\^,73  
yXf+dMv
  
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for(int i=0;i<nStartPos.length;i++) i{r[zA]$  
{ )W1[{?  
if(!fileSplitterFetch.bDownOver) wid
  
{ q%XjJ -s:  
breakWhile = false; ~Yre(8+M  
break; \3x+Z!  
} cxIAI=JK  
} z\K-KD{Ad  
if(breakWhile) K)
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break; .AF\[IQ  
k~JTQh*,w  
.8wF> 8  
//count++; On,z#A  
//if(count>4) QO4eDSW  
// siteStop(); NkAu<> G _  
} LfvRH?<W  
`U>]*D68  
-8SZ}J  
System.err.println("文件下载结束！"); l?HC-_Pbh  
} u!McPM8Yk  
catch(Exception e){e.printStackTrace ();} c2PBYFCyC  
} r6nWrO>y  
V@`%k]k  
|#B)`r8  
//获得文件长度 _A=i2?g  
public long getFileSize() *(sv5c!0M8  
{ ^j1iCL!  
int nFileLength = -1; P R_| 8H|  
try{ v5W-f0Jo  
URL url = new URL(siteInfoBean.getSSiteURL()); j% '~l#nw  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >ffQ264g=i  
httpConnection.setRequestProperty("User-Agent","NetFox"); UxnZA5Lk*  
pO2XQYhrY  
z%$
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int responseCode=httpConnection.getResponseCode(); S AKIFNE  
if(responseCode>=400) A=np?
wc  
{ 6L-3cxqf\  
processErrorCode(responseCode); Bey9P)_Of  
return -2; //-2 represent access is error o9Tsyjbj  
} :T#f&|Gg;  
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=ibKdPtTh^  
String sHeader; O#)YbaE  
.gCun_td#  
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for(int i=1;;i++) |gfG\fL3V  
{ 161IWos  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); |
  
//Utility.log(in.readLine()); [`1@`5SL-  
sHeader=httpConnection.getHeaderFieldKey(i); \CYKj_c  
if(sHeader!=null) :7s2M  
{ B06W(y,3Q>  
if(sHeader.equals("Content-Length")) cfHtUv  
{ VzWH9%w  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )c.!3n/pb  
break; 2UTmQOm  
} 0 l
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} k jx<;##R8  
else :79u2wSh  
break; < WQ ~X<1D  
} ?p>m;Aq  
} Wyb+K)Tg  
catch(IOException e){e.printStackTrace ();} z#d*Odc  
catch(Exception e){e.printStackTrace ();} -s7a\H{~  
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Utility.log(nFileLength); Q|7m9~  
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return nFileLength; f
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} z:A_  
:VX2&*  
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//保存下载信息（文件指针位置） s=<65  
private void write_nPos() 8,)<,g-/=  
{ 0*KL*Gn  
try{ )vGxF}I3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); O*>`md?MH  
output.writeInt(nStartPos.length); perhR!#J  
for(int i=0;i<nStartPos.length;i++) R'^J#"[  
{ eo&G@zwN  
// output.writeLong(nPos); zuJ@@\75  
output.writeLong(fileSplitterFetch.nStartPos); m=60a@o]  
output.writeLong(fileSplitterFetch.nEndPos); H2yPVJ\Y)"  
} 4UMOC_  
output.close(); r(g#3i4Q  
} N^'(`"J s  
catch(IOException e){e.printStackTrace ();} jN/snU2\0  
catch(Exception e){e.printStackTrace ();} jT4 m(j  
} pwA~?$B1  
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//读取保存的下载信息（文件指针位置） bj@f<f`  
private void read_nPos() CxrsP.  
{ )eH?3""  
try{ MwaRwk;  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); FW3uq^  
int nCount = input.readInt(); D=M'g}l  
nStartPos = new long[nCount]; mJsU7bD`  
nEndPos = new long[nCount]; 12l1u[TlS  
for(int i=0;i<nStartPos.length;i++) |)[&V3+|  
{ 
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nStartPos = input.readLong(); b{.Y?.U  
nEndPos = input.readLong(); KBgFS%-W  
} UW{C`^?=B  
input.close(); -+:t%A?  
} m:cWnG  
catch(IOException e){e.printStackTrace ();} k8,s<m  
catch(Exception e){e.printStackTrace ();} .RWq!Z=)3  
} _D8:p>=  
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96%N  
private void processErrorCode(int nErrorCode) "7w=LhzV[$  
{ 'T]Ok\  
System.err.println("Error Code : " + nErrorCode); -gv[u,
R  
} %Lp#2?*  
% "^CrG  
lN*"?%<
x>  
//停止文件下载 +^[SXI^JaJ  
public void siteStop() 5-:H  
{ `~h8D9G  
bStop = true; ov1#BeQ  
for(int i=0;i<nStartPos.length;i++) ob9=/ R?i  
fileSplitterFetch.splitterStop(); *~d<]U5h  
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} soA] f  
} Q 34-a"6)  
//负责部分文件的抓取 ;33SUgX  
**FileSplitterFetch.java Q}1qt4xy*  
*/ -#r=  
package NetFox; 'K|F{K  
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import java.io.*; 5.l
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import java.net.*; -5@hU8B'a  
1|$J>  
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public class FileSplitterFetch extends Thread { \\Nt^j3qR  
0RN7hpf&`  
S
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String sURL; //File URL xN6}4JB  
long nStartPos; //File Snippet Start Position a@#<qf8g  
long nEndPos; //File Snippet End Position f2k~(@!h  
int nThreadID; //Thread's ID DKG;up0  
boolean bDownOver = false; //Downing is over ;bFd*8?;  
boolean bStop = false; //Stop identical ~l*[=0}  
FileAccessI fileAccessI = null; //File Access interface >P-'C^:V=  
)ZpMB  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException '~xiD?:  
{ Sy^@v%P'A  
this.sURL = sURL; Or-LQ^~  
this.nStartPos = nStart; a,e;(/#\7  
this.nEndPos = nEnd; n.1$p  
nThreadID = id; uIR   
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _$KkSMA~_  
} ;.7]zn.X]2  
w} r mYQ  
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public void run() x#t?`  
{ ;ih;8  
while(nStartPos < nEndPos && !bStop) }{.V^;  
{ \# 1p  
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try{ J$&2GAi  
URL url = new URL(sURL); rWJKK  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3vEwui-5  
httpConnection.setRequestProperty("User-Agent","NetFox"); +xNq8yS  
String sProperty = "bytes="+nStartPos+"-"; I<S*"[nV  
httpConnection.setRequestProperty("RANGE",sProperty); FmQiy+.|  
Utility.log(sProperty); QG09=GQ  
$^W|@et{ ]  
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InputStream input = httpConnection.getInputStream(); 3C2~heO>|  
//logResponseHead(httpConnection); cd4HbSp  
)~#3A@  
DOq"=R+  
byte[] b = new byte[1024]; DK#Tr: 7  
int nRead; 'N/u<`)  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) cgR8+o  
{ t]xR`Rr;X  
nStartPos += fileAccessI.write(b,0,nRead); z/i&Lpr:  
//if(nThreadID == 1) }L>0}H  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); rC6Eg
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} wLo<gA6;  

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Utility.log("Thread " + nThreadID + " is over!"); kM3#[#6$!  
bDownOver = true; Jv~^hN2  
//nPos = fileAccessI.write (b,0,nRead); Nk?/vMaw  
} ]F"@+_E  
catch(Exception e){e.printStackTrace ();} {Vf].l:kn  
} xxpzz(S ]A  
} 8>(/:u_x  
A9LVS&52  
mh#_lbe'  
//打印回应的头信息 7M$cIWe$
 
public void logResponseHead(HttpURLConnection con) M?I^`6IOc8  
{ {ApjOIxk  
for(int i=1;;i++) qrcir-+  
{ V|pO";%>,  
String header=con.getHeaderFieldKey(i); Q=^TKsu  
if(header!=null) #X0Y8:vj  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 1c4:'0  
Utility.log(header+" : "+con.getHeaderField(header)); %5j*e  
else 2QKt.a  
break; :%IB34e  
} ^-(DokdBn  
} 8#RL2)7Uy`  
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`Cz_^>]|=  
public void splitterStop()
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{ 7~
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bStop = true; m5cRHo<9Y  
} n"nfEA3{`  
"FLiSz%ME  
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} I\|.WrMNi  
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%t]{C06w+{  
/*
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**FileAccess.java Uf~5Fc1d =  
*//文件访问(定位，写)
U=[isi+7  
package NetFox; lOHW9Z  
import java.io.*; {X-a6OQj  
d/\ajQ1::  
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public class FileAccessI implements Serializable{ t_\&LMD  
H"wIa8A  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节  Rp6q)  
RandomAccessFile oSavedFile; =|H.r9-PK6  
long nPos; }w{E<C(M  
'|G8yojz  
[x -<O:r=P  
public FileAccessI() throws IOException {N@Pk[!  
{ G}@a]EGm  
this("",0); )g`~,3G  
} ~Sx\>wBlc  
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6u{%jSA>D\  
public FileAccessI(String sName,long nPos) throws IOException ]6,D9^{;  
{ 3]kN9n{  
oSavedFile = new RandomAccessFile(sName,"rw"); ;dTxQ_:  
this.nPos = nPos; bl#6B.*=  
oSavedFile.seek(nPos); %Hu.FS5'  
} #j"GS/y"  
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.d+zF,02Z  
public synchronized int write(byte[] b,int nStart,int nLen) 6+:;Mb_S  
{ 593!;2/@  
int n = -1; ,Uy;jk  
try{ Ei89Ngp\}  
oSavedFile.write(b,nStart,nLen); 3Qu-X\  
n = nLen; kv<(N  
} ul!q)cPb{  
catch(IOException e) X#o;`QM  
{ _.SpU`>/f  
e.printStackTrace (); [<nd+3
E  
} )-25?B  
`tl-] ^Y2  
Yh{5O3(;  
return n; M*aYcIU((  
} NosOd*S  
)#sN#ZR$  
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} {d> 6*b  
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."`||@|  
/* 7t+H94KG7  
**SiteInfoBean.java t;_1/mt  
*/ (*\y  
package NetFox; LdnTdh?  
X,D ]S@  
w{GEWD{&  
public class SiteInfoBean { kB=5=#s  
%
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VREDVLQT  
private String sSiteURL; //Site's URL olK*uD'`  
private String sFilePath; //Saved File's Path <}F(G-kV6  
private String sFileName; //Saved File's Name )M8@|~~  
private int nSplitter; //Count of Splited Downloading File vgi`.hk  


&%T*sR  
juxAyds  
public SiteInfoBean() cG4}daK]d  
{//nSplitter的缺省值为5 XnRm9%  
//default value of nSplitter is 5 !$<Kp6  
this("","","",5); >L$9fn/J  
} P=X)Ktmv  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) OK2\2&G  
{ hPUZ{#;n  
sSiteURL= sURL; 4I2#L+W  
sFilePath = sPath; {ea*dX872:  
sFileName = sName; R S] N%`]  
this.nSplitter = nSpiltter; kD6Iz$tr  
4v2JrC;  
5Hs!s+  
} 1;vwreJ  

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rw75(Lp{  
public String getSSiteURL() |C>\ku*  
{ -o57"r^x  
return sSiteURL; ]NKz5[9D  
} [5Zi\'~UH)  
 nWUau:%  
ep
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public void setSSiteURL(String value) P#"_H}qC*  
{ T7N\b]?j@Y  
sSiteURL = value; ,QLy}=N  
} tR_DN  
o_r{cnu  
^$<:~qq!  
public String getSFilePath() OOYdrv,  
{ Vc+~yh.)  
return sFilePath; ;}k_  
} T;i+az{N:V  
?XVox*6K&  
m3|l-[!OA"  
public void setSFilePath(String value) =UxKa`  
{ },#AlShZu  
sFilePath = value; \3)U~[O>:  
} <iM}p^jX9  
~}Z{hs)  
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public String getSFileName() <lWBhrz  
{ ~u r}6T  
return sFileName; x_= 3!)  
} A64c,Uv  
|xpOU*k  
" pL5j  
public void setSFileName(String value) u3HaWf3  
{ Apkb!"}>  
sFileName = value; ~-~iCIaTb  
} (AHTv8  
#c-Jo[%G  
q\Z9.T+Qo  
public int getNSplitter() %@%~<U)W  
{ YW"nPZNPy~  
return nSplitter; nDNK}O~'  
} 'f6!a5qC  
O\
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4n%|h-!8  
public void setNSplitter(int nCount) KCn#*[  
{ ,_:6qn{  
nSplitter = nCount; +@<@x4yt  
} zZV9`cqZ{  
} iF1zLI<A  
RMAbu*D0  
)(yKm/50  
/* z@2nre  
**Utility.java <p[RhP  
*/ M*F`s&vM  
package NetFox; ' &Nv|v\V  
$ccCI \  
i^eDM.#X  
public class Utility { ~Yg+bwh  
0:eK}tC  
$EZr@n  
public Utility() h5[.G!  
{ ^_o:Ddz?l"  
= Ruq  
!1P<A1K  
} t0)hdX  
mm N$\2  
//线程睡眠 5(y Q-/6C+  
public static void sleep(int nSecond) ?#L5V'ZZ*  
{ 1["IT.,f.  
try{ 'he&h4fm  
Thread.sleep(nSecond); x!UGLL]_M  
} ?)4c!3#  
catch(Exception e) Q>\9/DjUp  
{ 0|?DA12Z  
e.printStackTrace (); QW&@>i  
} {;hRFQ^b  
} N ^H H&~V  
T7*p!0  
//日志 M5+K[Ir/y9  
public static void log(String sMsg)  j g_;pn  
{ $"Nqto~  
System.err.println(sMsg); f
Jn4'Q*U  
} KPa&P:R3  
wr2F]1bh@  
5I5#LQv0  
public static void log(int sMsg) I@q4D1g  
{ ae] hCWK  
System.err.println(sMsg); J(`(PYo\i  
} aMyf
|l.  
} ~-NlTx  
d C6t+  
UujKgL4  
/* OI)/J;[-e  
**TestMethod.java {-s7_\|p(  
*/ %X(|Z4dL  
package NetFox; {^Q1b.=  
>8DZj&j  
AHTQF#U^  
public class TestMethod { 200Fd8Ju  
PJ'@!jx  
0,m@BsK  
public TestMethod() PL
7_j  
{ ///xx/weblogic60b2_win.exe Yn-;+ 4 K  
try{ |A:+[35  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); "@&I*1&  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;5=5HYx%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ~)!vhdBe  
fileFetch.start(); [1.>9ngj  
} ](^BQc  
catch(Exception e){e.printStackTrace ();} iR4!X()  
t%30B^Ii%K  
)>WSuf j  
} %<'PSri  
N x/_+JWje  
YXTd^M~@D  
public static void main(String[] args) [f-<M@id/  
{ .KE2sodq  
new TestMethod(); c+]5[6  
} +q)B4A'J!  
} EP]OJ$6I  
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