http断点续传简单实现（java)

/* bHP-Z9riv  
**SiteFileFetch.java =4[zt^WX"  
*/ 2
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package NetFox; f|`{PP`\  
import java.io.*; gk&?h7P"<  
import java.net.*; V>nY?  
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public class SiteFileFetch extends Thread { T/3UF  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 
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long[] nStartPos; //开始位置 iZ:-V8{  
long[] nEndPos; //结束位置 ;gc2vDMv  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 1a'JNe$  
long nFileLength; //文件长度 M}c_KFMV  
boolean bFirst = true; //是否第一次取文件 ~vXul`x  
boolean bStop = false; //停止标志 ;A C] *  
File tmpFile; //文件下载的临时信息 /i"EVN`t  
DataOutputStream output; //输出到文件的输出流 7HF\)cz2  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） wEp/bR1=  
public SiteFileFetch(SiteInfoBean bean) throws IOException _%P%~`?!  
{ &dS+!<3  
siteInfoBean = bean; *be+x RY  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )uaB^L1  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); pQ>V]M  
if(tmpFile.exists ()) qM`SN4C  
{ "~;jFB8  
bFirst = false; :Cuae?O,  
read_nPos(); ufo?ZFq@$L  
} i^> RjR  
else <(iOzn  
{  :DD4BY  
nStartPos = new long[bean.getNSplitter()]; HP8pEo0Y  
nEndPos = new long[bean.getNSplitter()]; A#i-C+"}  
} 4e(@b3y  
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} jlB3BwG{w  
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public void run() aT0 y  
{ fG{oi(T  
//获得文件长度 ;~K($_#H  
//分割文件 ,|H!b%ZW  
//实例FileSplitterFetch xq{4i|d)  
//启动FileSplitterFetch线程 1@ina`!1O  
//等待子线程返回 c;e,)$)-|  
try{ (y36NH+  
if(bFirst) #i,O "`4  
{ ?( '%QfT  
nFileLength = getFileSize(); ?{2-,M0  
if(nFileLength == -1) `7j,njCX.  
{ 4{

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System.err.println("File Length is not known!"); |WX4L7yrhK  
} 0QpWt  
else if(nFileLength == -2) <(^pHv7Q  
{ <uvshZv  
System.err.println("File is not access!"); 
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} okv7@8U#p  
else |j+~Td3})&  
{ BO_^3Me*  
for(int i=0;i<nStartPos.length;i++) YszhoHYh  
{ !9 F+uc5  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5J;c;PF  
} <Zi
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for(int i=0;i<nEndPos.length-1;i++) 4D13K.h`O  
{ Wama>dy%  
nEndPos = nStartPos[i+1]; /[s$A?  
} J]UHq$B  
nEndPos[nEndPos.length-1] = nFileLength; }pA4
#{)  
} ,Tx8^|b#F  
} *}J_STM  
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//启动子线程 )N/KQ[W  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; by<2hLB9Q  
for(int i=0;i<nStartPos.length;i++) \9p;md`  
{ `+uXL9
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), */)gk=x8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;
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nStartPos,nEndPos,i); lySaJd  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); KkY22_{ac  
fileSplitterFetch.start(); mm8O  
} 2XtQ"`)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *pMA V[^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,b4&$W].  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ~iWSc8-  
nEndPos = " + nFileLength); A@ME7^w7  
// fileSplitterFetch[nPos.length-1].start(); g6V*w
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*C BCQp[$  
//等待子线程结束 gUp0RPs  
//int count = 0; zCrcCr  
//是否结束while循环 wu')Q/v  
boolean breakWhile = false; *QG;KJ%  
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while(!bStop) E`|qFG<  
{ 7 SZR#L  
write_nPos(); e?>suIB  
Utility.sleep(500); 2e"}5b5  
breakWhile = true; GN0'-z6Uy  
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for(int i=0;i<nStartPos.length;i++) ,)1e+EnV&  
{ 7W"menw  
if(!fileSplitterFetch.bDownOver) `t6L'%\  
{ 4(82dmKO  
breakWhile = false; =HHg:"  
break; c29Z1Zs2)  
} &u-Bu;G.e  
} 5ov%(QI  
if(breakWhile) Fev3CV$  
break; [3Rj?z"S  
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s 'xmv{|  
//count++; !`lqWO_/ :  
//if(count>4) ".f:R9-  
// siteStop(); e%6{P  
} WKsx|a]U  
,6"n5Ks}  
[[Z>(d$8  
System.err.println("文件下载结束！"); %SCu29km  
} c ?XUb[  
catch(Exception e){e.printStackTrace ();} 'OCo1|iK~  
} 8 -A7  
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//获得文件长度 zi .
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public long getFileSize() oE1]vX  
{ (p=GR#  
int nFileLength = -1; )7g_v*  
try{ N1~$ +  
URL url = new URL(siteInfoBean.getSSiteURL()); ZnLk :6'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \*aLyyy3  
httpConnection.setRequestProperty("User-Agent","NetFox"); _9|@nUD  
<z2mNq  
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int responseCode=httpConnection.getResponseCode(); [oLQd-+  
if(responseCode>=400) XS8~jBjx  
{ \/'n[3x  
processErrorCode(responseCode); K"j=_%{  
return -2; //-2 represent access is error 8p{  
} MmH_gR  
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String sHeader; OB^?cA>  
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for(int i=1;;i++) e uHu}  
{ e
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); %W',cu  
//Utility.log(in.readLine()); |!5T+H{Sj  
sHeader=httpConnection.getHeaderFieldKey(i); r5fkt>HZ  
if(sHeader!=null) 1[g!^5W  
{ p]z54 ~  
if(sHeader.equals("Content-Length")) c_$&Uii  
{ XW_xNkpL5c  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Dh(T)yc  
break; 9^#gVTGXv  
} [j]J_S9jJ  
} vq:OH H  
else LYg$M@  
break; [2 w<F[  
} vs)I pV(  
} 0$ 9;pzr  
catch(IOException e){e.printStackTrace ();} m2q;^o:J  
catch(Exception e){e.printStackTrace ();} NwlRPyt  
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Utility.log(nFileLength); G<-9U}~76  
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return nFileLength; ]n]uN~)9  
} 4:eq{n  
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?~JxO/K  
//保存下载信息（文件指针位置） K*U=;*p)  
private void write_nPos() e(=~K@m  
{ "K+N f  
try{ t#pqXY/;D  
output = new DataOutputStream(new FileOutputStream(tmpFile)); +V);'"L  
output.writeInt(nStartPos.length); A6UdWK  
for(int i=0;i<nStartPos.length;i++) !E{
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{ YUVc9PV)Ws  
// output.writeLong(nPos); 7hF,gl5  
output.writeLong(fileSplitterFetch.nStartPos); Bw]L2=d  
output.writeLong(fileSplitterFetch.nEndPos); c."bTq4tJ  
}
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output.close(); B==a  
} <% 7P  
catch(IOException e){e.printStackTrace ();} ,;cel^.b  
catch(Exception e){e.printStackTrace ();} j`|^s}8t  
} ,hTwNVWI9  
,+\4 '`  
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//读取保存的下载信息（文件指针位置） 9 yW~79n  
private void read_nPos() k99gjL`  
{ <5ft6a2fQ  
try{ )`s;~_ZZ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); o[6vxTH  
int nCount = input.readInt(); _<%\h?W$  
nStartPos = new long[nCount]; xOVA1pb,  
nEndPos = new long[nCount]; AFINm%\/0  
for(int i=0;i<nStartPos.length;i++) yxG:\y b  
{ }c35FM,  
nStartPos = input.readLong(); u 5Eo  
nEndPos = input.readLong(); k_K,J6_)  
} B-\,2rCCZ  
input.close(); zM_
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} k(-Z@  
catch(IOException e){e.printStackTrace ();} A#Q0{z@H  
catch(Exception e){e.printStackTrace ();} 9
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} 9raHSzK@d  
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private void processErrorCode(int nErrorCode) %\X P:  
{ Th7wP:iDP  
System.err.println("Error Code : " + nErrorCode); k1f3?l vlU  
} Avs7(-L+s  
/FP~jV!z  
i!S
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//停止文件下载 J0?$v6S  
public void siteStop() rV8(ia  
{ M
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bStop = true; VO.-.  
for(int i=0;i<nStartPos.length;i++) j<l#qho{h  
fileSplitterFetch.splitterStop();  /,1SE(  
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} 0(Y%,q  
} 9,S,NvSq  
//负责部分文件的抓取 ee&nU(pK  
**FileSplitterFetch.java 
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*/ F-$Z,Q]S  
package NetFox; 9nng}em>.  
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import java.io.*; U9<_6Bsd  
import java.net.*; SW,q}-  

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public class FileSplitterFetch extends Thread { 3 R5%N ~  
_, \y2&KT  
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String sURL; //File URL X!U]`Qh  
long nStartPos; //File Snippet Start Position "[awmZ:wo  
long nEndPos; //File Snippet End Position /\TQc-k?2  
int nThreadID; //Thread's ID W.yV/fu  
boolean bDownOver = false; //Downing is over ..??O^  
boolean bStop = false; //Stop identical t*o7,  
FileAccessI fileAccessI = null; //File Access interface ,]f),;=  
Z -pyFK\  
- waX#UT=  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException !aQIh  
{ sEoZ1E  
this.sURL = sURL; *w=z~Jq^R"  
this.nStartPos = nStart; P-[fHCg~  
this.nEndPos = nEnd; G{F6  
nThreadID = id; nped  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 M]J[6EW  
} H!Wis3S3G  
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public void run() ov1Wr#s  
{ UE"7

  
while(nStartPos < nEndPos && !bStop) e-~hS6p(  
{ M,&tA1CH  
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try{ Pg7>ce  
URL url = new URL(sURL); +<gg
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); IZ+*`E  
httpConnection.setRequestProperty("User-Agent","NetFox"); +z+F-  
String sProperty = "bytes="+nStartPos+"-"; +:}kZDl@ X  
httpConnection.setRequestProperty("RANGE",sProperty); )r=9]0=  
Utility.log(sProperty); &8Zeq3~  
M#ZT2~+CT  
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InputStream input = httpConnection.getInputStream(); yU*
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//logResponseHead(httpConnection); a/#+92C  
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byte[] b = new byte[1024]; T&]Na  
int nRead; vxb@9eb!H  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 0%/,>IR>r  
{ wc"9A~  
nStartPos += fileAccessI.write(b,0,nRead); n4Vwao/9x  
//if(nThreadID == 1) M Z2^@It  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ih; aBS  
} $Ru&>D#stK  
kPWBDpzN  
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Utility.log("Thread " + nThreadID + " is over!"); Xj%,xm>}!u  
bDownOver = true; ]Z=Ij gr$  
//nPos = fileAccessI.write (b,0,nRead); g#w`J\iz  
} &i)helXs]  
catch(Exception e){e.printStackTrace ();} (9E( Q*J5x  
} X2LV&oi  
} Cb4_ ?OR0  
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kj-=xhJ{=  
//打印回应的头信息 d<!IGt4Ky  
public void logResponseHead(HttpURLConnection con) f`,
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{ l(#1mY5!q8  
for(int i=1;;i++) lVP |W:~K  
{ @`6}`k  
String header=con.getHeaderFieldKey(i); Cpe#[mE  
if(header!=null) QPX`l0V
 
//responseHeaders.put(header,httpConnection.getHeaderField(header)); vf[&7n  
Utility.log(header+" : "+con.getHeaderField(header)); vG2.]?  
else p=H3Q?HJ}  
break; ;>8kPG  
} 02(h={  
} 5} G:D  
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i@XB&;*c\  
public void splitterStop() 0Q`&inwh  
{ iKhH^V%j  
bStop = true; drI\iae{^  
} `UQEXoB)  
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} @7%.7LK  
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/* Q(e{~ ]*  
**FileAccess.java x)_r@l`$ix  
*//文件访问(定位，写) J+|/-{g  
package NetFox; V9Hl1\j^  
import java.io.*; F\-Si!~oOz  
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public class FileAccessI implements Serializable{ `c9'0*-  
yPN+W8}f  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 2T?TM! \Q  
RandomAccessFile oSavedFile; ?!y"OrHg  
long nPos; f3vF"O  
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public FileAccessI() throws IOException [~)x<=H8{  
{ SO_>c+Dw  
this("",0); %J!NL0x_  
} ]Jn2Ra"j  
-=mwy  
>Nh`rkR2[  
public FileAccessI(String sName,long nPos) throws IOException zSXA=   
{ /NU103F yt  
oSavedFile = new RandomAccessFile(sName,"rw"); `XgFga)  
this.nPos = nPos; {m[Wyb(  
oSavedFile.seek(nPos); j^nu|  
} Du!._  
O:YJ%;w  
I .P6l*$  
public synchronized int write(byte[] b,int nStart,int nLen) RX>2~^  
{ G "brT5:  
int n = -1; kP^*hO!%  
try{ " #v%36U  
oSavedFile.write(b,nStart,nLen); RG}}Oh="v  
n = nLen; *|KVN&#  
} QNpuTZn#Q  
catch(IOException e) ;_N5>3C:  
{ "V}qf3qU  
e.printStackTrace (); KUKI qAA  
} #&BS ?@  
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return n; oY.\)eJ~>  
} cmDT +$s  
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} H1&RI4XC  
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/* $.8
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**SiteInfoBean.java ti2  
*/ 7 :U8 f:  
package NetFox; A ~&+F>Z  
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public class SiteInfoBean { p6[ (81  
A[JM4x   
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private String sSiteURL; //Site's URL #pA[k-  
private String sFilePath; //Saved File's Path C6^j#rl  
private String sFileName; //Saved File's Name wS$46M<  
private int nSplitter; //Count of Splited Downloading File j^EbO3  
bEI!Ja  
8zmv 5trt  
public SiteInfoBean() BS2?!;,8  
{//nSplitter的缺省值为5 PGX+p+wB  
//default value of nSplitter is 5 XwPx9+b6j  
this("","","",5); :Q-F9o J  
} Dbz]{_Y;  
w2zp#;d  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) RL&lKHA  
{ ZqK]jT6V/X  
sSiteURL= sURL; O-!,Jm   
sFilePath = sPath; 1X&B:_  
sFileName = sName; v3-?CQb(  
this.nSplitter = nSpiltter; R|Y~u*D  
%),!2_ x~  
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} .'lN4x  
#{,h@g}W  
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public String getSSiteURL() [@2s&
Ct;  
{ O?E6xc<8  
return sSiteURL; @a(oB.i  
} r0btC@Hxy  
2 ~-( A  
_6rKC*Pe1  
public void setSSiteURL(String value) Euu ,mleM  
{ ~6d5zI4\  
sSiteURL = value; H\+-cvl  
} Le&;g4%  
Tz` ,{k  
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public String getSFilePath() $?f]ZyZr.  
{ X9~p4ys9{  
return sFilePath; K7RKF$Z\  
} 40.AM1Z0f  
P)1
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public void setSFilePath(String value) \h#9oPy  
{ voh^|(:(TH  
sFilePath = value; >'Hx1;  
} usH%dzKK  
^Y 7U1I  
all*P #[X  
public String getSFileName() >76 |:Nq  
{ oHsP
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return sFileName; bA*"ei+!  
} <kbnu7?a*  
L[.<o{  
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public void setSFileName(String value) ~U%j{8uH  
{ f4 O]`U  
sFileName = value; "tX7%(  
} gh61H:tkR  
vJThU$s-  
GNZ#q)qT  
public int getNSplitter() C P&o%Uc*  
{ yHOqzq56  
return nSplitter; 5rN7':(H!%  
} PUKVn+h  
?Cc :)  
BA*&N>a  
public void setNSplitter(int nCount) iAHZ0Du  
{ O! (85rp/  
nSplitter = nCount; Ql8^]gbp+  
} c(&AnIlS  
} AysL-sqR  
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kQ[Jo%YT?E  
/* b"3uD`  
**Utility.java c_DaNEfaY  
*/ 9tAE#A  
package NetFox; #/s7\2  
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public class Utility { Iu%^*K%  
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public Utility() ->3uOF!q  
{ A$ J9U3+O  
*?p ^6vO  
=-
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} 6"%@L{UQ  
ZIe+  
//线程睡眠 bl`D+/V   
public static void sleep(int nSecond) FvAbh]/4  
{ 1y~L8!:L  
try{ C$t.C rxx  
Thread.sleep(nSecond);  d~sJ=)  
} jQ)L pjS1  
catch(Exception e) P*7S3Td  
{ &M$Bt} <  
e.printStackTrace (); Enu!u~1]F  
} e) ]RA?bF  
} {wHvE4F2  
drbe#FObX  
//日志 :q(D(mK  
public static void log(String sMsg) }'v{dK  
{ %pH)paRAP  
System.err.println(sMsg); PP],HB+*[  
} */4tJG1U  
"cNg:  
r1+c/;TpZ  
public static void log(int sMsg) ed=n``P~}  
{ C0gfJ~M)  
System.err.println(sMsg); =,O/,2)  
} q?(A!1(u  
} ' 4,y  
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zf`5>h|  
/* ^)Smv\Md  
**TestMethod.java 4{Q$!O>  
*/ pa>p%  
package NetFox; J9NsHr:A[  
&ycjSBK  
~KJ,SLzhx9  
public class TestMethod { WUzSlZq  
(Z5q&#f  
E2h(w_l  
public TestMethod() JIVo=5c}  
{ ///xx/weblogic60b2_win.exe K*TnUQ  
try{ C?8PT/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); AbL5 !'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); J0&zb'1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); B^H4Q 4-  
fileFetch.start(); TFNUv<>X  
} "tfn?n0  
catch(Exception e){e.printStackTrace ();} 3(aRs?/O  
W&HF?w}s  
p 7 ,f6kG  
} lB=(8.  
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public static void main(String[] args) _2wAaJvA  
{ izXbp02  
new TestMethod(); rH[5~U  
} :8](&B68gE  
} ~o:rM/!Ba  
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