http断点续传简单实现（java)

/* hOB\n!  
**SiteFileFetch.java ,xYsH+ybA  
*/ DMQNr(w{!2  
package NetFox; Dk`4bYK  
import java.io.*; 43>9)
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import java.net.*; Pc(n@'m~  
|[Ie.&)  

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public class SiteFileFetch extends Thread { X&(ERY,h  
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SiteInfoBean siteInfoBean = null; //文件信息Bean o8'Mks  
long[] nStartPos; //开始位置 V5O=iMP  
long[] nEndPos; //结束位置 ySQ-!fQnP  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 I/HV;g:#  
long nFileLength; //文件长度 K3rBl!7v  
boolean bFirst = true; //是否第一次取文件 ~`2&'8  
boolean bStop = false; //停止标志 u`Z0{d  
File tmpFile; //文件下载的临时信息 zr.+'  
DataOutputStream output; //输出到文件的输出流 nuSN)}b<Q  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） `z}vONXpAX  
public SiteFileFetch(SiteInfoBean bean) throws IOException * -KJh_  
{ j/H>0^  
siteInfoBean = bean; c6,s+^^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); l Io9,K
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); F#1 Kk#t  
if(tmpFile.exists ()) 1l+kO,X]  
{ 5L-lpT8P  
bFirst = false; ACigeK^C}E  
read_nPos(); d&|z=%9xl  
} 6F*-qb3  
else heL$2dZ5H  
{ /5Zp-Pq  
nStartPos = new long[bean.getNSplitter()]; y9C;T(oi;  
nEndPos = new long[bean.getNSplitter()]; 1E
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}
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} Z5G]p4  
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public void run() sI&i{D  
{ xF( bS+(o  
//获得文件长度 6<x~Mk'u)  
//分割文件 qH#r-  
//实例FileSplitterFetch ?a5h iN0  
//启动FileSplitterFetch线程 H2qf'  
//等待子线程返回 ?YF${  
try{ 3CR@' qG-  
if(bFirst) ;,1=zhKU.  
{ lPM3}52Xu  
nFileLength = getFileSize(); pOC% oj  
if(nFileLength == -1) f64(a\Rw!^  
{ M1oPOC\0.  
System.err.println("File Length is not known!"); ^WE4*.(  
} +|y*
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else if(nFileLength == -2) |KL')&"  
{ 
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System.err.println("File is not access!"); Z_H?WGO  
} AV40:y\RW  
else Q6"uK  
{ gNShOu  
for(int i=0;i<nStartPos.length;i++) <9P4}`%)3  
{ M|\^UF2e  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); o#qH2)tb  
} Y3-gUX*w0  
for(int i=0;i<nEndPos.length-1;i++) 25 CZmsg  
{ 1T ( u  
nEndPos = nStartPos[i+1]; Kv(z4z  
} *~p(GC  
nEndPos[nEndPos.length-1] = nFileLength; :e*DTVv8  
} 8b|OXWl  
} n(g)UNx  
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//启动子线程 )
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; '|A|vCRCG  
for(int i=0;i<nStartPos.length;i++) E2@`d6  
{ %$@1FlqX;  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .%=V">R  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), qnB<k,8T  
nStartPos,nEndPos,i); -?s&pK
i  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yuOS&+,P  
fileSplitterFetch.start(); veeI==]  
} >F1G!#$0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~h
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Nln`fE/Ht  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 9lf*O0Z&n  
nEndPos = " + nFileLength); 6{q;1-8j+j  
// fileSplitterFetch[nPos.length-1].start(); vT|`%~Be  
(n,u|}
8Y  
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//等待子线程结束 8S\RN&T$  
//int count = 0; u*3NS$vH  
//是否结束while循环 :.kZR;  
boolean breakWhile = false; 07V8;A<,  
,7W:fwdR  
{( #zcK  
while(!bStop) bu>qsU3  
{ $B;_Jo\|  
write_nPos(); WJ|:kuF  
Utility.sleep(500); f`jc#f5+'  
breakWhile = true; nVE9^')8V  
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for(int i=0;i<nStartPos.length;i++) dBSbu=^$)  
{ (hIF]>,kl  
if(!fileSplitterFetch.bDownOver) Lxv6!?v|  
{ pY@Y?Jj  
breakWhile = false; *z'8
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break; "wAf.=F  
} oH^(qZ8W  
} %Y]=1BRk}  
if(breakWhile) w~z[wmOkp  
break; #2RiLht  
/kgeV4]zR  
hfqqQ!,l!  
//count++;  ~*M$O&  
//if(count>4) r> k-KdS  
// siteStop(); "g>.{E5  
} )"Q*G/+2Ie  
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System.err.println("文件下载结束！"); oc7$H>ET1  
} CS 8jA\  
catch(Exception e){e.printStackTrace ();} TX}T|ri  
} .f:n\eT):  
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Ot
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//获得文件长度 %<"}y$J  
public long getFileSize() G,f-.  
{ &gtG~mp<L  
int nFileLength = -1; 4[yIOs  
try{ xe4Oxo  
URL url = new URL(siteInfoBean.getSSiteURL()); DZ$` 4;C[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); W#'c5:m 4  
httpConnection.setRequestProperty("User-Agent","NetFox"); VA]e  
1TS0X:TCn  

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int responseCode=httpConnection.getResponseCode(); -`b8T0?oK  
if(responseCode>=400) (Glr\q]jF\  
{ =w$tvo/  
processErrorCode(responseCode); /J3ZL[o?Q  
return -2; //-2 represent access is error r X'*|]  
} JTU#vq:TY  
vAb^]d
 
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String sHeader; {sVY`}p|  
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for(int i=1;;i++) 7y^%7U \  
{ #m<tJnEO  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); M;w?[yEZ  
//Utility.log(in.readLine()); :~F:/5
 
sHeader=httpConnection.getHeaderFieldKey(i); 59r_#(uo  
if(sHeader!=null) K+Y^>N4m  
{ -d+aV1n  
if(sHeader.equals("Content-Length")) `F t]MR  
{ ~]HN9R^&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); P>i%7:OMZA  
break; P 1XK*GZ  
} m<rhIq  
} NGC,lv  
else '3 33Ctxy  
break; 1x)ZB~L  
} ;G |i^  
} ^n1%OzGK#  
catch(IOException e){e.printStackTrace ();} A#8q2n270*  
catch(Exception e){e.printStackTrace ();} KLoE&ds  
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Utility.log(nFileLength); O.`Jl%  
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return nFileLength; VU`OO$,W  
} m: n`g1  
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;-P)
m  
//保存下载信息（文件指针位置） A4C+5R  
private void write_nPos() dU)]:>Uz  
{ \Ig68dFf%  
try{ K5Q43e1  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3`E=#ff%  
output.writeInt(nStartPos.length); pM;vH]|  
for(int i=0;i<nStartPos.length;i++) ~{h
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{ gTl<wo +  
// output.writeLong(nPos); gr-9l0u  
output.writeLong(fileSplitterFetch.nStartPos); FBx_c;)9Z  
output.writeLong(fileSplitterFetch.nEndPos); /1N6X.Zb  
} uvDzKMw~R  
output.close(); &QRE"_g  
} Q;11N7+  
catch(IOException e){e.printStackTrace ();} c'uhK8|  
catch(Exception e){e.printStackTrace ();} Hy.AyU|L  
} ~Q{QM:k  
!oPq?lW9  
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//读取保存的下载信息（文件指针位置） PZxAH9 S?  
private void read_nPos() <+MyZM(z>  
{ ]i(-I <`  
try{ %^sTU4D5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1"Z@Q`}  
int nCount = input.readInt(); [(Xy.L7x  
nStartPos = new long[nCount]; 'c2W}$q  
nEndPos = new long[nCount]; De7Ts  
for(int i=0;i<nStartPos.length;i++) -9N@$+T  
{ S/|,u`g-  
nStartPos = input.readLong(); :B3[:Mp
L}  
nEndPos = input.readLong(); j',W 64  
} k@zy  
input.close(); *e
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} [Wd-Zn%  
catch(IOException e){e.printStackTrace ();} ]Chj T}  
catch(Exception e){e.printStackTrace ();} `&\Q +W  
} X%z }VA  
+$4(zPs@  
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private void processErrorCode(int nErrorCode) Vk< LJ S  
{ |*Z$E$k:  
System.err.println("Error Code : " + nErrorCode); rpeJkG@+  
} 7Q\|=$2  
mc=LP>uoS  
DPi_O{W>  
//停止文件下载 5T sUQc  
public void siteStop() J+rC
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{ V5+SWXZ  
bStop = true; "$s~SIUB  
for(int i=0;i<nStartPos.length;i++) J>fQNW!{  
fileSplitterFetch.splitterStop(); mF` B#  
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} h(W
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} dJ$"l|$$  
//负责部分文件的抓取 fXrXV~'8  
**FileSplitterFetch.java d%l{V6  
*/ ^u3V E  
package NetFox; /mo(_  
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import java.io.*; rG,5[/l  
import java.net.*; LYlDc;<A  
UK9@oCIB  
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public class FileSplitterFetch extends Thread { ^C2\`jLMY  
U,nEbKJgk  
 KWLbD#  
String sURL; //File URL f~}H  
long nStartPos; //File Snippet Start Position ySI~{YVM  
long nEndPos; //File Snippet End Position VfT*7_  
int nThreadID; //Thread's ID ~-wPP
{!  
boolean bDownOver = false; //Downing is over jxYc2  
boolean bStop = false; //Stop identical (O0Urm  
FileAccessI fileAccessI = null; //File Access interface R|i/lEq  
H'Yh2a`!o  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException V5}B:SUB  
{ s-dLZ.9F  
this.sURL = sURL; B"%{i-v>**  
this.nStartPos = nStart; @?h/B=56  
this.nEndPos = nEnd; 6uKTGc4  
nThreadID = id; Jx'i2&hGN  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 M'_9A  
} Tw +  
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public void run() T#bu V  
{ ZvcJK4hi  
while(nStartPos < nEndPos && !bStop) g-Pwp[!qkf  
{ b!M"VDjQ  
Nj("|`9"  
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try{ ,o]4?-  
URL url = new URL(sURL); ?yh}/T\qp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *L!!]Q2c  
httpConnection.setRequestProperty("User-Agent","NetFox"); MDF%\Sx  
String sProperty = "bytes="+nStartPos+"-"; g2unV[()_  
httpConnection.setRequestProperty("RANGE",sProperty); =J1rlnaaEL  
Utility.log(sProperty); #-h\.#s  
c'*a{CV4P  
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InputStream input = httpConnection.getInputStream(); 8i?l02  
//logResponseHead(httpConnection);  &y<ZE  
jsNF#
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Wh&8pH:  
byte[] b = new byte[1024]; L/"0ws_  
int nRead; LzYO$Ir:g  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >0l"P"]  
{ !ti6  
nStartPos += fileAccessI.write(b,0,nRead); (%`QhH  
//if(nThreadID == 1) k__$Q9qj(  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /T.KbLx~q  
} NV#FvM/#"  
r-h#{==*c  
>MPr=W%E  
Utility.log("Thread " + nThreadID + " is over!"); g[w,!F  
bDownOver = true; Z}-Vf$O~  
//nPos = fileAccessI.write (b,0,nRead); JMTvSXr  
} n8.kE)?  
catch(Exception e){e.printStackTrace ();} ['ksP-=  
} KoS*0U<g6  
} [d* ~@P  
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%TsPyiYl  
//打印回应的头信息 _D|^.)=U|  
public void logResponseHead(HttpURLConnection con) `c'W-O/  
{ hTwA%  
for(int i=1;;i++) 'g9"Qv?0{`  
{ [V}S<Xp  
String header=con.getHeaderFieldKey(i); ]D,MiDph  
if(header!=null) 5aa<qtUjH  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); j^`hzh3S  
Utility.log(header+" : "+con.getHeaderField(header)); (!:cen~|[  
else )Z %T27r,^  
break; J/3_C6U
Z  
} 'TAUE{{  
} S/ibb&  
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public void splitterStop() N~F RM& x  
{ Zk[&IBE_  
bStop = true; JH8zF{?  
} pFJB'=c  
]%!
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} Y F*OU"2U  
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/* gR@C0  
**FileAccess.java 'ky b\q  
*//文件访问(定位，写) QFIL)'K  
package NetFox; h;jIYxj  
import java.io.*; (#;`"Yu  
%E_b'[8  
3 zn W=  
public class FileAccessI implements Serializable{ E#F/88(  
)Jv[xY~  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 kkK kf'  
RandomAccessFile oSavedFile; t>H`X~SR?  
long nPos;  -@ZiS^l  
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public FileAccessI() throws IOException V=1Bo~  
{ hxS 6:5Uc  
this("",0); R-P-i0~  
} K+6e?5t  
q
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public FileAccessI(String sName,long nPos) throws IOException Ldn8  
{ CXCpqcC  
oSavedFile = new RandomAccessFile(sName,"rw"); 5MS
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this.nPos = nPos; ce6__f5?  
oSavedFile.seek(nPos); CR|lt  
} ,$eK-w  
<`0h|m'U  
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public synchronized int write(byte[] b,int nStart,int nLen) 3 LdQ]S  
{ X*L;.@xA  
int n = -1; &
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try{ C XHy.&Vt  
oSavedFile.write(b,nStart,nLen); 8?FbtBAn  
n = nLen; HQ{JwW!m  
} ^S6u<,  
catch(IOException e) PpsIhMq@  
{ @ps1Dr4s  
e.printStackTrace (); 1 tR_8lC  
} UswZG^Wh  
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return n; OnWx#84  
} ~g7l8H67  
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(@#M!'  
} LjU'z#  
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/* 8 B**8yg.  
**SiteInfoBean.java ?i`l[+G  
*/ L_w+y  
package NetFox; 7+hK~  
c=AOkX3UD  
LbtX0^  
public class SiteInfoBean { HD N9.5S  
!@'%G6:.  
-)~SM&  
private String sSiteURL; //Site's URL -[qq(E  
private String sFilePath; //Saved File's Path K6olYG>  
private String sFileName; //Saved File's Name wd/< 8>2X  
private int nSplitter; //Count of Splited Downloading File f>ZyI{  
SIKOFs  
{3!E4"p
 
public SiteInfoBean() "YB**Y  
{//nSplitter的缺省值为5 ?3O9eZY@  
//default value of nSplitter is 5 eznypY=  
this("","","",5); 2<hp
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} h!m_PgRSs  
X=C1/4wU  
&[&r2>a  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) SwU\ q]^|Z  
{ uf&N[M  
sSiteURL= sURL; ^_ojR4  
sFilePath = sPath; HV/cc"  
sFileName = sName; dik9 >*"|o  
this.nSplitter = nSpiltter; ` \A(9u*  
TO-$B8*nq  

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} .IJ_jt-^d  
<x\7L2#p  
^'jEnN(  
public String getSSiteURL() eh[_~>w  
{ we#wH-  
return sSiteURL; a" H WGY  
} Skz|*n|eY  
76vy5R(.  
~y$!48o  
public void setSSiteURL(String value) !`mZ0c+  
{ F]mgmYD%  
sSiteURL = value; #oJ5k8Wy  
} ;}z\i  
r&Ca"dI  
]qB:PtX  
public String getSFilePath() *GUAO){'  
{ Yhp]x
  
return sFilePath; bZx!0>h  
} H_?o-L?+  
CU7F5@+  
^2wLxXO6  
public void setSFilePath(String value) VxzkQ}o  
{ YJ:3!B>Zo  
sFilePath = value; +ki{H}G21  
} ,&4qgp{)  
i55x`>]&sb  
[&*6_q"V  
public String getSFileName() 2m>-dqg  
{ '$ef+@y  
return sFileName; qOaQxRYm%Y  
} @/&b;s73  
ESoAzo,u  
%{;Qls%[t  
public void setSFileName(String value) 7E!7"2e a  
{ kbPE "urR  
sFileName = value; 3DaQo0N  
} =_]2&(?  
,^8MB.  
NU(AEfF  
public int getNSplitter() BGr.yEy  
{ "g+z !4b#  
return nSplitter; @u._"/K  
} *1@:'rJ  
>5G>D~b  
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public void setNSplitter(int nCount) ",>H(wJ8  
{  Yav2q3  
nSplitter = nCount; dO7;}>F$n  
} ?r_l8  
} K)Zlc0e  
#'4OYY.  
=:+0)t=ao  
/* 9%sM*[A  
**Utility.java DF{OnF  
*/ 0Aa`p3.)  
package NetFox; Npn=cLC&  
H.G!A6bd  
KLC{7"6e)  
public class Utility { TzBzEiANn  
@d"wAZzD?  
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public Utility() 7<9L?F2  
{ I?Q+9Rmm`J  
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} V^Rkt%JY  
tZ2e!<C  
//线程睡眠 D@X+{  
public static void sleep(int nSecond) F~U!1)  
{ hnWo|! ,O$  
try{ KjB/.4lLq  
Thread.sleep(nSecond);  uIMe  
} _{~]/k  
catch(Exception e) G%u9+XV1#  
{ n
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e.printStackTrace (); x|eeRf|  
} s~2
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} +CM7C%U   
Lv1{k\aw  
//日志 d77r9  
public static void log(String sMsg) -v?hqWMp#  
{ 7t-Lz| $"  
System.err.println(sMsg); }%{MPqg  
} NN 0Q`r,8}  
.I$}KE)  
^;F{)bmu+)  
public static void log(int sMsg) ;HOPABWz)  
{ G[idN3+#  
System.err.println(sMsg); .]Mn^2#j  
} 7.bN99{xPM  
} OY"6J@[z  
ZkB3[$4C=5  
/,|CrNwY*  
/* (s
w-~U%  
**TestMethod.java 8n4V cu  
*/ cjUL
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package NetFox; L(&}Wv  
*Zd84wRSj  
#l1Qe`  
public class TestMethod { (foBp  
u@%|kc`  
e,A)U5X  
public TestMethod() Ul Mi.;/^  
{ ///xx/weblogic60b2_win.exe /48 =UK  
try{ +?`b=6e(`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); bdh(WJh%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6-,m}Ce\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); PI5j"u UO  
fileFetch.start(); @{Py%  
} TF
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catch(Exception e){e.printStackTrace ();} |kiJ}oy  
'4;6u]d)2  
-pTI?  
} )"O{D`uX  
6&2LWaWMo$  
;)!"Ty|  
public static void main(String[] args) G5]1s  
{ C>|@& o1  
new TestMethod(); {,O`rW_eS  
} aw}+'(?8]  
} \Rk$t
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