http断点续传简单实现（java)

/* )8k6GO8|  
**SiteFileFetch.java CjST*(,b  
*/ %idnm  
package NetFox; %(e=Q^=  
import java.io.*; H{}6`;W  
import java.net.*; >N3
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public class SiteFileFetch extends Thread { Q3KBG8  
2 43DdIG$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean L{Th>]X  
long[] nStartPos; //开始位置 <T}#>xHs3  
long[] nEndPos; //结束位置 l9jcoVo.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ^ID%pd  
long nFileLength; //文件长度 +|0m6)J]  
boolean bFirst = true; //是否第一次取文件 'v,W gPe  
boolean bStop = false; //停止标志 3a5H<3w_  
File tmpFile; //文件下载的临时信息 Ltj}>.+  
DataOutputStream output; //输出到文件的输出流 XmnqZWB  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） vbFAS:Y:+  
public SiteFileFetch(SiteInfoBean bean) throws IOException hh?'tb{  
{ "2h#inS  
siteInfoBean = bean; 6RF01z|~_  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 54OYAkPCk  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); J\%:jg( m  
if(tmpFile.exists ()) >YW>=5_  
{ PU>;4l  
bFirst = false; u,pm\  
read_nPos(); Kzm_AHA)  
} =#u2Rx%V  
else z~BB|-kp1  
{ >hhd9  
nStartPos = new long[bean.getNSplitter()]; Cse0!7_T  
nEndPos = new long[bean.getNSplitter()]; !Q#b4f  
} :X!(^a;]  
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} Y[H_?f=;%  
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public void run() S ~_%  
{ 3UaP7p+d  
//获得文件长度 BOWTH{KR<<  
//分割文件 =.%ZF]Oe+#  
//实例FileSplitterFetch SUEw5qitB  
//启动FileSplitterFetch线程 `~RV  
//等待子线程返回 ? vlGr5#  
try{ ~L1O\V i  
if(bFirst) *"5a5.`%,  
{ gB"Tc[l1  
nFileLength = getFileSize(); rEf\|x=st:  
if(nFileLength == -1) :}-u`K*  
{ g IKm  
System.err.println("File Length is not known!"); SQ!lgm1bA  
} DG-vTr  
else if(nFileLength == -2) >R:+ml  
{ D7.
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System.err.println("File is not access!"); ? 1{S_  
} +E:(-$"R  
else [0LqZ<\5  
{ F:g{rm[
  
for(int i=0;i<nStartPos.length;i++) 16y$;kf8  
{ ob7_d
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); >(rB[ZJ  
} 5:d2q<x:{  
for(int i=0;i<nEndPos.length-1;i++) ]aRD6F:L  
{ ##@#:B  
nEndPos = nStartPos[i+1]; gdK/:%u3  
}
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nEndPos[nEndPos.length-1] = nFileLength; PPPwDsJ  
} GN9_ZlC  
} _e_%U<\4  
#[W[|m  
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//启动子线程 @qDrTH]5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; [J`G`s!  
for(int i=0;i<nStartPos.length;i++) QL2y,?Mz7  
{ `Cf en8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), weV#%6=5\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), W~F/ZrT3A  
nStartPos,nEndPos,i); UK>=y_FYO  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); RG3G},Q   
fileSplitterFetch.start(); \#jDQ  
} )JQQ4D  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #6jwCEo=V  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); }hitU(5t0  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", mJ>99:W+  
nEndPos = " + nFileLength); &U*J{OP
|  
// fileSplitterFetch[nPos.length-1].start(); *UoHzaIqz  
6a7iLQA  
AV4HX\`{P0  
//等待子线程结束 2P_^@g  
//int count = 0; 25n(&NV  
//是否结束while循环 WkySTc  
boolean breakWhile = false; 8ysK VF  
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while(!bStop) zZc@;S#  
{ r_,m\'~s!  
write_nPos();
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Utility.sleep(500); o;>3z*9?3  
breakWhile = true; )
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for(int i=0;i<nStartPos.length;i++) N8YBu/  
{ K}<!{/fi)  
if(!fileSplitterFetch.bDownOver) Gi2ad+QH-  
{ E D^
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breakWhile = false; O;e8ft '|  
break; $:E}Nj]{&  
} BH0#Q5  
} !8@rK$DB  
if(breakWhile) tP Efz+1N  
break; o+_/)c  
^GrkIh0nL  
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//count++; k\c &2T]
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//if(count>4) IO!1|JMr6  
// siteStop(); *Iwk47J ;a  
} e9`uD|KAS|  
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System.err.println("文件下载结束！"); )ehB)X  
} 5\w=(c9A  
catch(Exception e){e.printStackTrace ();} uH&,%k9GVK  
} Z0ncN])  
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//获得文件长度 /LI~o~m1)  
public long getFileSize() mfngbFa1  
{ 8PoH
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int nFileLength = -1; [+'B
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try{ MLt'YW^  
URL url = new URL(siteInfoBean.getSSiteURL()); S#h'\/S  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); nGv23R(?G  
httpConnection.setRequestProperty("User-Agent","NetFox"); P~\a)Szy  
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int responseCode=httpConnection.getResponseCode();  ^%5~;  
if(responseCode>=400) gVa+.x]  
{ XSp x''l  
processErrorCode(responseCode); K$<`4#i  
return -2; //-2 represent access is error M9Nk=s! 3  
} \[[TlB>  
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String sHeader; Z6IJo%s  
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for(int i=1;;i++) >@)*Sn9"  
{ g
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~\IF9!  
//Utility.log(in.readLine()); xSpMyXrQ  
sHeader=httpConnection.getHeaderFieldKey(i); r6d0x  
if(sHeader!=null) Ws-6W!Ib%  
{ zmrQf/y{R  
if(sHeader.equals("Content-Length")) 4Qa@`  
{ 8hTR*e!+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )-bD2YA{  
break; 9W{,=.%MX$  
} 0+T*$=?  
} dT5J-70Fl  
else &Ki>h  
break; 2[jL^XMM  
} zKIGWH=qqm  
} O&`U5w  
catch(IOException e){e.printStackTrace ();} c3=-Mq9Q  
catch(Exception e){e.printStackTrace ();} .:w#&yM [U  
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Utility.log(nFileLength); ]i-P-9PA4  
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return nFileLength; To3^L_v"
 
} CQ@LmTW[  
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//保存下载信息（文件指针位置） aXMv(e+  
private void write_nPos() !\QeBd+  
{ 8O,?|c=>  
try{ b6 $,Xh  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^#]c0  
output.writeInt(nStartPos.length); x>}B#  
for(int i=0;i<nStartPos.length;i++) ):e+dt  
{ %1Yz'AiW[  
// output.writeLong(nPos); ov8 ByJc  
output.writeLong(fileSplitterFetch.nStartPos); $j57LY|r  
output.writeLong(fileSplitterFetch.nEndPos); 8EOh0gk7  
} \Ke8W,)ew  
output.close(); b`$yqi<[  
} %B@!  
catch(IOException e){e.printStackTrace ();} <>%,}j 9  
catch(Exception e){e.printStackTrace ();} 85'nXYN{d  
} 9X(Sk%  
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//读取保存的下载信息（文件指针位置） JjQ8|En  
private void read_nPos() _IWxYp  
{ )B6
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try{ K4C^m|e  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); YydA6IK4  
int nCount = input.readInt(); j.DHqHx  
nStartPos = new long[nCount]; 98GlhogWt  
nEndPos = new long[nCount]; N#4N?BBP"  
for(int i=0;i<nStartPos.length;i++) +=7:4LFOL  
{ #<4--$Xo  
nStartPos = input.readLong(); -;$nb~y  
nEndPos = input.readLong(); -OrR $w|e  
} f-4.WW2FN  
input.close(); PY?8[A+  
} -IadHX}]t  
catch(IOException e){e.printStackTrace ();} @D)Z{=>{=5  
catch(Exception e){e.printStackTrace ();} OOokh
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} D?^Y`G$.  
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private void processErrorCode(int nErrorCode) Ql8bt77eI-  
{ V>Fesm"aq  
System.err.println("Error Code : " + nErrorCode); #n3ykzoqIX  
}  Hy]  
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RP! X8~8  
//停止文件下载 *nRNg
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public void siteStop() ?iv=53<c#  
{ /ylc*3e'4  
bStop = true; jZd}OC<  
for(int i=0;i<nStartPos.length;i++) RF?DtNuq  
fileSplitterFetch.splitterStop(); xzm@ v(  
O-#TZ   
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} +BL{@,zr  
} L%t@,O#,  
//负责部分文件的抓取 [|RjHGf  
**FileSplitterFetch.java zXZir7NfM  
*/ irKI
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package NetFox; O,s.D,S  
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import java.io.*; <{Q'&T  
import java.net.*; 2'|8Q\,:4Z  
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public class FileSplitterFetch extends Thread { Y3Oz'%B  
,DQjDMjrf  
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String sURL; //File URL 'wQv3;  
long nStartPos; //File Snippet Start Position ]*N1t>
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long nEndPos; //File Snippet End Position ]s_8A`vm  
int nThreadID; //Thread's ID QJGKQ2^ n  
boolean bDownOver = false; //Downing is over )OP){/   
boolean bStop = false; //Stop identical [ MyE2^  
FileAccessI fileAccessI = null; //File Access interface ]Oeh=gq  
ldqLM  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException pQa:pX  
{ b5a.go  
this.sURL = sURL; [k<1`z3  
this.nStartPos = nStart; swcd&~9r  
this.nEndPos = nEnd; M4yI`dr6  
nThreadID = id; ~h$wH{-U#  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 zjl!9M!  
} .; Q:p*  
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vB'>[jvA|  
public void run() aZS7sV28  
{ m Y,|J\w@  
while(nStartPos < nEndPos && !bStop) :-T*gqj|  
{ E_T2z4lw  
9=`Wp6Gmn  
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try{  #
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URL url = new URL(sURL); 6gL-OJNo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~f\G68c  
httpConnection.setRequestProperty("User-Agent","NetFox"); (Z]HX@"{J  
String sProperty = "bytes="+nStartPos+"-"; ~`ny@WD9  
httpConnection.setRequestProperty("RANGE",sProperty); #W>QY Tp  
Utility.log(sProperty); Yf@e=:  
X}ma]  
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InputStream input = httpConnection.getInputStream(); }_9,w;M$  
//logResponseHead(httpConnection); g4p  
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byte[] b = new byte[1024]; :rMM4  
int nRead; 8.AR.o  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Q4*?1`IsR  
{ l7H qo)  
nStartPos += fileAccessI.write(b,0,nRead); {76c%<`WaP  
//if(nThreadID == 1) u$#Wv2|mk  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); CC=d I  
} CAq/K?:8  
*g}Yw  
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Utility.log("Thread " + nThreadID + " is over!"); c/N@zum,{  
bDownOver = true; S8[=S  
//nPos = fileAccessI.write (b,0,nRead); -VxTx^)>  
} i':ydDOOHA  
catch(Exception e){e.printStackTrace ();} ULrr=5&8  
} J]lrS  
} gxz-R?.  
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^bg2[FV  
//打印回应的头信息 #} ~qqJ G2  
public void logResponseHead(HttpURLConnection con) d@`M CchCB  
{ A1'hlAGF  
for(int i=1;;i++) 3vhnwDcK  
{ %~L>1ShtU  
String header=con.getHeaderFieldKey(i); Nkxmm/Z  
if(header!=null) zJP6F.Ov!  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); drzL.@h|  
Utility.log(header+" : "+con.getHeaderField(header)); dm0QcW4  
else S5~VD?O,  
break; Ya>oCr}
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} fVb-$  
} d\x7Zw>  
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public void splitterStop() /VmR<C?
h  
{ ~\{^%~[48  
bStop = true; m_?d=o  
} S
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8} =JKR^cK  
} @d Jr/6Yx  
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/* n1!?"m!  
**FileAccess.java XsnF~)YW  
*//文件访问(定位，写) M\yT).>z  
package NetFox; pZ/>[TP(%F  
import java.io.*; T&Lb<'f  
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public class FileAccessI implements Serializable{ 8\{^|y9-  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 z dO#0tN  
RandomAccessFile oSavedFile; }CeCc0M  
long nPos; d&Ef"H  
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public FileAccessI() throws IOException 3B1cb[2y  
{ T49zcJf;  
this("",0); DGzw8|/(  
} o6V}$wT3J  
mEG#>Gg$  
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public FileAccessI(String sName,long nPos) throws IOException K)J(./  
{ *zr(Zv  
oSavedFile = new RandomAccessFile(sName,"rw"); wE~V]bmtW  
this.nPos = nPos; _q~=~nub  
oSavedFile.seek(nPos); 4'0Dr++  
} ki85!k=Q2  
 trAkcYd  
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public synchronized int write(byte[] b,int nStart,int nLen) hi
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{ ;VWAf;U;B  
int n = -1; mauI42  
try{ o<N nV  
oSavedFile.write(b,nStart,nLen); ^<e.]F25M  
n = nLen; {?yr'*  
} z<yU-m2h
 
catch(IOException e) ]Ux<aiY]a  
{ v8y1b%  
e.printStackTrace (); 1Z9qjV%^  
} b j'Xg  
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return n; z_|/5$T>U  
} Dc_yM  
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} M8tRjNWS?  
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/* rwI  
**SiteInfoBean.java ]wtb-PC  
*/ <kCU@SK
 
package NetFox; B&@?*^.  
62Z#YQ}x  
l6d$V9A  
public class SiteInfoBean { 5=Di<!a;  
!1ED~3/X  
B#M5}QT|2  
private String sSiteURL; //Site's URL 6Aku1h  
private String sFilePath; //Saved File's Path ZSG
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private String sFileName; //Saved File's Name LbkF   
private int nSplitter; //Count of Splited Downloading File CY"/uSB  
JhLgCnm  
/C6k+0ApMT  
public SiteInfoBean() =17t- [  
{//nSplitter的缺省值为5 bdc&1I$  
//default value of nSplitter is 5 +1D+]*t_?[  
this("","","",5); iB498t  
} M#8uv-L  
sashzVwJ-=  
m8o(J\]  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [Lz
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{ smnSDS  
sSiteURL= sURL; m_)FC-/pSl  
sFilePath = sPath; lb3]$Da   
sFileName = sName; !Y[lQXv  
this.nSplitter = nSpiltter; m5r7  
#':fkIYe'  
r_-_a(1R:  
} yp({>{u7  
|%' nVxc4r  
CL+}|7O(  
public String getSSiteURL() 
8]U{;|';  
{ 6,0_)O}\b  
return sSiteURL; H
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} \Z+z?K O  
B
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iLkZ"X.'|1  
public void setSSiteURL(String value) FgB&b  
{ [x,>?~6ek  
sSiteURL = value; H{=21\a\  
} ,.}]ut/Tm  
SN1}xR$  
\Hn>oonph  
public String getSFilePath() 3GUZ;jdn  
{ /JWGifH  
return sFilePath; j4^97  
} eep1I :N  
Bi @2  
:gep:4&u  
public void setSFilePath(String value) Y\$ySvZ0  
{ ,uSQNre\j  
sFilePath = value; ]hFW73FV  
} 9f<MQ6_UU  
/(.mp<s0  
$3s@}vLd  
public String getSFileName() =g|IG [V  
{ Ljp%CI[i  
return sFileName; IrqZi1  
} e,Uo#T6J  
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public void setSFileName(String value) lXjXqk\  
{ 2AO~HxF  
sFileName = value; #0y)U;dA+w  
} >8qQK r\"  
4
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Yd#/1!A7u  
public int getNSplitter() f (F)1  
{ k[:bQ)H  
return nSplitter; t3&LO~Ye  
} 8&)DE@W  
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public void setNSplitter(int nCount) YTexv;VNb|  
{ A*}.EClH  
nSplitter = nCount; 2gCX}4^3b  
} SU/BQ3  
} wv\w;'  
NqDHCI  
=[@zF9  
/* JU^ly
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**Utility.java ).sRv6/c  
*/ @jsDq Ln  
package NetFox; Q=/</|  
/7t>TY
ip!  
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public class Utility { 7]||UuF<  
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public Utility() [`c^4E  
{ r0,:J  
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} 5`gQ~  
(<}
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//线程睡眠 ysQ,)QoiR{  
public static void sleep(int nSecond) ak |WW]R  
{ )`A3M)  
try{ [N#,K02mk  
Thread.sleep(nSecond); yl1gx  
} 2gq9k}38  
catch(Exception e) I/L_@X<*r  
{
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e.printStackTrace (); ] 0B2# d  
} &'}/f5s|  
} g#t[LI9(F[  
O^^C;U@U<1  
//日志  .5y+fL  
public static void log(String sMsg) 6T#+V37  
{ WzF !6n!h  
System.err.println(sMsg); ?l^1 *Q,  
} ,~OwLWi-|X  
(KF=On;=Y  
t<|NLk.  
public static void log(int sMsg) S7L=#+Z  
{ T2!6(, s9  
System.err.println(sMsg); Gch[Otq]%  
} #[`:'e  
} }0X:F`Y-  
:kf`?u  
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/* =MLcm^b  
**TestMethod.java eK!V );  
*/ y10h#&k  
package NetFox; 371 TvZ4  
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fIwV\,s  
public class TestMethod { tGl;@V@Qj  
CS=qj-(  
2U:H545]]  
public TestMethod() 4@ML3d/  
{ ///xx/weblogic60b2_win.exe 0#S W!b|%  
try{ AG?dGj^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); E7Y`|nT  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);
XoCC/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); m$W <  
fileFetch.start(); %d(^d  
} g47-db"5  
catch(Exception e){e.printStackTrace ();} 'toa@5  
P5#r,:zL  
(v}>tb*#`  
} >ey\jDr#O  
Z]j*9#G1s  
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public static void main(String[] args) q&/Yg,p\  
{ N%"Y  
new TestMethod(); %y|)=cm[  
} MF'$~gxo  
} ,>eMG=C;g  
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