http断点续传简单实现（java)

/* c 6"Ib)  
**SiteFileFetch.java ? }yfKU`  
*/ 7]Em,  
package NetFox; s"%lFA"-  
import java.io.*; 4
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import java.net.*; 5G[x}4U  
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public class SiteFileFetch extends Thread { Z^yNLF*&V  
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SiteInfoBean siteInfoBean = null; //文件信息Bean VT\"q1)p  
long[] nStartPos; //开始位置 X|}2_B  
long[] nEndPos; //结束位置 j.m(ltGh  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _Mk7U@j+9  
long nFileLength; //文件长度 +D&Pp0xe  
boolean bFirst = true; //是否第一次取文件 =wVJ%  
boolean bStop = false; //停止标志 &xXEnV  
File tmpFile; //文件下载的临时信息 *nC(-(r:J`  
DataOutputStream output; //输出到文件的输出流 zF`3gl.  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 8)L*AdDAW!  
public SiteFileFetch(SiteInfoBean bean) throws IOException /@"Y^  
{ :"Y*<=x#2  
siteInfoBean = bean; I|9 SiZ0  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ~g6 3qs  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Kcy@$uF{2  
if(tmpFile.exists ()) [;A[.&6  
{ u 8^{  
bFirst = false; SJ?cI!=x  
read_nPos(); MSw$_d  
} >yB(l
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else >6<q8{*  
{ #wY0D_3@1  
nStartPos = new long[bean.getNSplitter()]; _%/}>L>-`8  
nEndPos = new long[bean.getNSplitter()]; YJ_\Ns+Ow  
} zmI]cD@G  
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} c!#:E`  
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public void run() E&`Nh5JfC  
{ ]
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//获得文件长度
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//分割文件 l{Dct\ #s  
//实例FileSplitterFetch K2{aNvR)t  
//启动FileSplitterFetch线程 k(t}^50^j  
//等待子线程返回 iK5_u2]Q  
try{ 9QQyl\  
if(bFirst) ?t](a:IX  
{ x3 >  
nFileLength = getFileSize(); nKoiG*PI  
if(nFileLength == -1) |~!U4D\  
{ t]aea*B  
System.err.println("File Length is not known!"); qIIJ4n  
} 8CbXMT  
else if(nFileLength == -2) H+E$:)gN  
{ \C,p
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System.err.println("File is not access!"); _P?s'HH  
} (o5j'2:.  
else t.p~\6
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{ 5Xn.CBd]  
for(int i=0;i<nStartPos.length;i++) lVOu)q@l7g  
{ x'<K\qp{{  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); zcrY>t#l  
} |`Or'%|PR  
for(int i=0;i<nEndPos.length-1;i++) J(DN!  
{ 9KWuN:Sg  
nEndPos = nStartPos[i+1]; ~6YMD  
} -m *Sq  
nEndPos[nEndPos.length-1] = nFileLength; [NMVoBvG  
} u .f= te  
} 21hv%CF\9  
^XbU~3(  
}}v9 `F  
//启动子线程 6AG`&'"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 1#IlWEg  
for(int i=0;i<nStartPos.length;i++) I/Jb!R ~  
{ ljTBvU  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >zAUW[]C:I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 86]p#n_>Fv  
nStartPos,nEndPos,i); ,XDRO./+T  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Gmwf4>"  
fileSplitterFetch.start(); *g?Po+ef%  
} 7X@mSXis  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~t9tnLc$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); n3AaZp[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", (aOv#Vor]%  
nEndPos = " + nFileLength); {9UEq0  
// fileSplitterFetch[nPos.length-1].start(); >leU:7  
4=<tWa|@9  
1`ayc|9BR  
//等待子线程结束 `x%'jPP1^  
//int count = 0; WSuw
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//是否结束while循环 fhL,aCS=  
boolean breakWhile = false; nt*Hc1I  
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while(!bStop) S<'[%ihx  
{ AbZKYF P  
write_nPos(); /|* Y2ETOr  
Utility.sleep(500); .L'
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breakWhile = true; ;>n,:355L  
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for(int i=0;i<nStartPos.length;i++) 0a80 LAK  
{ th;{V%:LW  
if(!fileSplitterFetch.bDownOver) +
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{ %CK^Si%+  
breakWhile = false; ^fZ&QK  
break; (sh)TBb5  
} >=[(^l  
} 'Lu__NfN  
if(breakWhile) '7XIhN9  
break; z`:lcF{V  
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//count++; FCnm1x#  
//if(count>4) hCC<?5q  
// siteStop(); (1#J%  
} Q%xC}||1s"  
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System.err.println("文件下载结束！"); h*-Pr8  
} z CvKDlL  
catch(Exception e){e.printStackTrace ();} PYGRsrcFd#  
} )jt #=9ZQ  
/5u<78GW1  
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//获得文件长度 x QIq^/F0  
public long getFileSize() @)fd}tV  
{ ouuuc9x]  
int nFileLength = -1; p6;OL@\~  
try{ ,^C--tgZJg  
URL url = new URL(siteInfoBean.getSSiteURL()); k |eBJ%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2AMo:Jqv  
httpConnection.setRequestProperty("User-Agent","NetFox"); u:=7l  
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int responseCode=httpConnection.getResponseCode(); u fw]=h)  
if(responseCode>=400) 9Gnc9_]I;W  
{ #`)(e JF  
processErrorCode(responseCode); >Wv;R2|  
return -2; //-2 represent access is error A<??T[  
} ~^1{B
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String sHeader; JU)dr4S?  
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for(int i=1;;i++) {0WHn.,2Y  
{ $42{HFGq  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ;IZwTXu!S  
//Utility.log(in.readLine()); c}2jmwq  
sHeader=httpConnection.getHeaderFieldKey(i); eQ]~dA8>  
if(sHeader!=null) `~By)?cT_>  
{ /w}u3|L$  
if(sHeader.equals("Content-Length")) t:'Mh9h7u  
{ De'_SD|=  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); L6|oyf  
break; ^SF&=NpV  
} ;EP:
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} w|K'M?N14  
else oYH^_V  
break; ,Ge
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} .nx2";oi  
} ` 2V19
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catch(IOException e){e.printStackTrace ();} oYm[V<nIl  
catch(Exception e){e.printStackTrace ();} G$F<$  
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Utility.log(nFileLength); )QU  
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return nFileLength; Ezd_`_@R  
} J;8IY=  
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//保存下载信息（文件指针位置） CDK5  
private void write_nPos() !xo{-@@wS  
{ fof
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try{ rrik,qyv6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ] Zy5%gI  
output.writeInt(nStartPos.length); B#Vz#y  
for(int i=0;i<nStartPos.length;i++) r{L> F]Tw  
{ >I-RGW'A  
// output.writeLong(nPos); *Doa*wQ  
output.writeLong(fileSplitterFetch.nStartPos); jtW!"TOY  
output.writeLong(fileSplitterFetch.nEndPos); S.-TOE  
} Y[}>CYO  
output.close(); #W4dkCd(pF  
} H4&lb}  
catch(IOException e){e.printStackTrace ();} w"-Lc4t+  
catch(Exception e){e.printStackTrace ();} /<|%yE&KhJ  
} U`,6 * MS  
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//读取保存的下载信息（文件指针位置） ^:^9l1]  
private void read_nPos() =5~jx  
{ FQ<Ju.  
try{ [+n*~
  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 4.[^\N  
int nCount = input.readInt(); ,St#Vla  
nStartPos = new long[nCount]; qNB<T('  
nEndPos = new long[nCount]; mwHB(7YS,  
for(int i=0;i<nStartPos.length;i++) $P^q!H4D  
{ S2sQOM@  
nStartPos = input.readLong(); YNKHN2E8  
nEndPos = input.readLong(); chM%]|gey  
} &^}1O:8e  
input.close(); a|t$l=|DD  
} XDOY`N^L  
catch(IOException e){e.printStackTrace ();} 1ySk;;3  
catch(Exception e){e.printStackTrace ();} 'YmIKIw  
} g?goZPZB  
f
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private void processErrorCode(int nErrorCode) /Kql>$I  
{ gY/"cq  
System.err.println("Error Code : " + nErrorCode); h-q3U%R4}@  
} [9evz}X  
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//停止文件下载 J\twZ>w~0  
public void siteStop() 6-N?mSQU  
{ '3/4?wi  
bStop = true; vdivq^%=a  
for(int i=0;i<nStartPos.length;i++) "l3_=Gua  
fileSplitterFetch.splitterStop(); H1|?t+oP  
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gc
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} il4^zj82  
} [B\h$IcRv  
//负责部分文件的抓取 xHvZV<#  
**FileSplitterFetch.java fphv  
*/ 4gI/!,J(b  
package NetFox; jS]ru-5.  
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import java.io.*; k]F[>26k  
import java.net.*; Xv ]W(f1  
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public class FileSplitterFetch extends Thread { 5sj4
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String sURL; //File URL }
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long nStartPos; //File Snippet Start Position Yb|
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long nEndPos; //File Snippet End Position 2b}t,&bv?  
int nThreadID; //Thread's ID Hq'`8f8N  
boolean bDownOver = false; //Downing is over PxWT1 !  
boolean bStop = false; //Stop identical e24WW^S  
FileAccessI fileAccessI = null; //File Access interface o
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?PuBa`zDE  
{ '}ptj@,  
this.sURL = sURL; ] {RDVA=]  
this.nStartPos = nStart; :C(=&g<]D  
this.nEndPos = nEnd; ^me-[ 5  
nThreadID = id; u%&`}g  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 dyz2.ZY~2  
} Yg]-wQrH  
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public void run() l+xX/A)  
{ jFQQ`O V  
while(nStartPos < nEndPos && !bStop) 2V- 16Q'%  
{ !E<[JM  
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try{ D=q:*x  
URL url = new URL(sURL); l: HTk4$0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p|X"@kuseO  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?AK(|  
String sProperty = "bytes="+nStartPos+"-"; =MQoC:l  
httpConnection.setRequestProperty("RANGE",sProperty); a#cCpE  
Utility.log(sProperty); k3lS8d7  
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InputStream input = httpConnection.getInputStream(); :%lTU  
//logResponseHead(httpConnection); }MJy +Z8&  
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byte[] b = new byte[1024]; }^ApJS(FQ  
int nRead; Sj%u)#Ub  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >{q]&}^U  
{ C)um9}  
nStartPos += fileAccessI.write(b,0,nRead); [<lHCQXJ/  
//if(nThreadID == 1) 5V?&8GTe  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {%rA1g  
} 0IsPIi"7  
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Utility.log("Thread " + nThreadID + " is over!"); -o^7r@6  
bDownOver = true; U$O\f18  
//nPos = fileAccessI.write (b,0,nRead); m ifxiV  
} \r/rBa\  
catch(Exception e){e.printStackTrace ();} ? ^0:3$La  
} R5N%e%[  
} CuaVb1r  
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//打印回应的头信息 SL Ws*aq  
public void logResponseHead(HttpURLConnection con) -$pzl,^ h  
{ }n]
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for(int i=1;;i++) ;,hwZZ
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{ iw3FA4{(  
String header=con.getHeaderFieldKey(i); >nJ\BPx  
if(header!=null) b)6D_Az7c  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %R}qg6dL  
Utility.log(header+" : "+con.getHeaderField(header)); OV1_|##LC  
else 0z`a1 %U  
break;
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} |UkR'Ma  
} Gt\lFQ  
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public void splitterStop() 9&$y}Y  
{ -WY<zJ  
bStop = true; 7o7)0l9!  
} ew>XrT=Zm  
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} %"q9:{m  
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/* 2]z8:a  
**FileAccess.java ,1y@Z 5wy  
*//文件访问(定位，写) {kA0z2Fe
 
package NetFox; Yk'XGr)  
import java.io.*; 6LvW?z(J  
Lm iOhx  
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public class FileAccessI implements Serializable{ bHY=x}Hv  
}fp-pe69z  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 (o 5s"b  
RandomAccessFile oSavedFile; EuEZ D+  
long nPos; =rMUov h  
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public FileAccessI() throws IOException IB(6+n,6s  
{ d?y4GkK  
this("",0); 3(="YbZ  
} ?qmRbDI  
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public FileAccessI(String sName,long nPos) throws IOException 6gL#C&  
{ C(eTR1  
oSavedFile = new RandomAccessFile(sName,"rw"); a4mn*,  
this.nPos = nPos; JYMiLph<  
oSavedFile.seek(nPos); I5X|(0es  
} ny]?I
  
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public synchronized int write(byte[] b,int nStart,int nLen) )%`c_FL@N=  
{ &DS/v)]  
int n = -1; g&^quZ"H  
try{ GF"hx`zyJ  
oSavedFile.write(b,nStart,nLen); ]{sU&GqBLe  
n = nLen; Ryl:a\  
} "SNn^p59k  
catch(IOException e) |'e^QpU5  
{ Q{O+  
e.printStackTrace (); Giid~e33  
} S){)Z  
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return n; Bj+S"yS  
} #QS`_TlKk  
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} ]vz%iv_  
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$|zX|  
/* >,v`EIg  
**SiteInfoBean.java `jDTzhO~  
*/ FVMD>=k  
package NetFox; /{EP*,/*  
E`kG-Q5Dw  
'@a}H9>}  
public class SiteInfoBean { aEBu *`-j  
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T"(&b~m2b4  
private String sSiteURL; //Site's URL 1Rt33\1J0  
private String sFilePath; //Saved File's Path dhC$W!N7!  
private String sFileName; //Saved File's Name 0XOp3  
private int nSplitter; //Count of Splited Downloading File -$t{>gO#Y  
-m\u  

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public SiteInfoBean() u^^vB\"^  
{//nSplitter的缺省值为5 JOj;^h  
//default value of nSplitter is 5 0B[="rTS7#  
this("","","",5); v|Pv 03%?7  
} bYcV$KJk  
R]JT&p|w.1  
-5)H<dAQZ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) %{7|1>8  
{ >d(~#Z`  
sSiteURL= sURL; EW}Bzh>b  
sFilePath = sPath; ##q2mm:a9P  
sFileName = sName; q?Cnav`DY  
this.nSplitter = nSpiltter; gK+4C  
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} AKY1o.>z  
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public String getSSiteURL() ,D5
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{ d}Xr}  
return sSiteURL; fIM,lt  
} Tg7an&#  
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_;W.q7b]  
public void setSSiteURL(String value) '%>=ZhO  
{ W4t;{b  
sSiteURL = value; 2_)\a(.Qu  
} {WJm  
G5{T5#  
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public String getSFilePath() O8f?; ]  
{ *HU &4E\a  
return sFilePath; l(yZO$
  
} adlV!k7RG  
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public void setSFilePath(String value) ?K1/ <PE+  
{ "H2EL}3/]  
sFilePath = value; WEAT01  
} f@6QvkIa  
e*sfPHt  
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public String getSFileName() GmK^}=frj  
{ +|*IZ:w)  
return sFileName; <:_wbVn-  
} 1kz\IQ{  
] ;KJ6  
i)\L:qF5  
public void setSFileName(String value) m.hkbet/R  
{ V#v`(j%  
sFileName = value; b}\N;D.{  
} evenq$ H  
%]\kgRr  
#+JG(^%B  
public int getNSplitter() 4d"r^y'  
{ 1v#%Ei$6`t  
return nSplitter; 7 G)ZN{'  
} G3txj  
}#3V+X  
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public void setNSplitter(int nCount) S&e0u%8mc  
{ I) rCd/  
nSplitter = nCount; e4-@f%5  
} 9X[kEl  
} u\a#{G;Z  
r+'qd)  
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/* (XVw"m/ye  
**Utility.java M\vwI"  
*/ Cmu@4j&  
package NetFox; iky|Tp  
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public class Utility { >u>5{4  
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public Utility() IO wj>t  
{ o\BOL3H  
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} ]E7F/O/.  
3^IpE];+:u  
//线程睡眠 Gq+z/Be  
public static void sleep(int nSecond) f W!a|?e$  
{ ksc;X$f&4  
try{ &\#sI9  
Thread.sleep(nSecond); 1Rq,
a  
} B|Du@^$  
catch(Exception e) fJ5
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{ i3dkYevs?  
e.printStackTrace (); <qtr   
} Wfu(*  
} 
^pxX]G]  
7X`l&7IXP  
//日志 bW$,?8(  
public static void log(String sMsg) )}g(b=  
{ *RDn0d[  
System.err.println(sMsg); H  >j  
} +j#+8Ze  
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public static void log(int sMsg) QaS1
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{ x%s-
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System.err.println(sMsg); F7 5#*  
} ?e`^P  
} rTM}})81  
hmvfw:Nq4  
kC WEtbz1  
/* oNr-Q& C,  
**TestMethod.java PZ2;v<  
*/ :C7_Jp*Qv  
package NetFox; ^tqzq0  
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public class TestMethod { >d*iD  
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8N!b>??  
public TestMethod() " f <Z=c  
{ ///xx/weblogic60b2_win.exe WgR).Yx  
try{
,
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); t,QyfN  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); DD7h^-x  
SiteFileFetch fileFetch = new SiteFileFetch(bean);
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fileFetch.start(); xRJ\E }/7  
} M.Y~1c4f  
catch(Exception e){e.printStackTrace ();} S\LkL]qx  
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}  0bz'&  
2!0c4a^z  
 ;ZH3{  
public static void main(String[] args) yaD~1"GA'O  
{ d^Inb!%w  
new TestMethod(); C^3 <={  
} 1cx
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} lAi6sPG)0  
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