http断点续传简单实现（java)

/* KE#$+,
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**SiteFileFetch.java 7>KQRLw  
*/ [{/$9k-aF?  
package NetFox; 6,3}/hgWJ$  
import java.io.*; n8Q* _?Z/  
import java.net.*; p&m ^
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public class SiteFileFetch extends Thread { cPm~` Zd  
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SiteInfoBean siteInfoBean = null; //文件信息Bean c0SX]4} G  
long[] nStartPos; //开始位置 n'Bmz  
long[] nEndPos; //结束位置 +L n M\n  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 m.Twgin  
long nFileLength; //文件长度 %L28$c3p  
boolean bFirst = true; //是否第一次取文件 u5/t2}^T  
boolean bStop = false; //停止标志 G6<HO7\  
File tmpFile; //文件下载的临时信息 J/= +r0c  
DataOutputStream output; //输出到文件的输出流 (A2U~j?Ry}  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） DYkC'+TEX  
public SiteFileFetch(SiteInfoBean bean) throws IOException ^b:Xo"q#H  
{ y3Y2QC(  
siteInfoBean = bean; )'=V!H#U*  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); G}s;JJax  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); > Z]P]e  
if(tmpFile.exists ()) #*+;B9
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{ 7 s7}?l9  
bFirst = false; ,R8n,az  
read_nPos(); l,^xX=,  
} pAMo XJ`  
else >2nF"?"=  
{ 7Onk!NH  
nStartPos = new long[bean.getNSplitter()]; 3V"dG1?  
nEndPos = new long[bean.getNSplitter()]; q$3HvZP  
} kGruo5A  
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} 3g^IXm:K$  
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public void run() &^AzIfX}Gw  
{ |e~u!V\m  
//获得文件长度 >}70]dN7b  
//分割文件 6|%^pjX5  
//实例FileSplitterFetch JThk Wx  
//启动FileSplitterFetch线程 !B0v<+;P8  
//等待子线程返回 Y=hPErw  
try{ CgN]dx*`  
if(bFirst) 3e#x)H/dr  
{ >
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nFileLength = getFileSize(); mf+K{y,L  
if(nFileLength == -1) `CPZPp,l6`  
{ s z;=mMr/Z  
System.err.println("File Length is not known!"); md.*  
} }R4(B2vup  
else if(nFileLength == -2) m2jwqx{G  
{ "$# $f  
System.err.println("File is not access!"); :O5Tr03z  
} G[ ,,L  
else \a\^(`3a[  
{ aeLBaS  
for(int i=0;i<nStartPos.length;i++) 1hF2eNh  
{ 2Y9y5[K,F)  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "tqS|ok.  
} unx;m$-c  
for(int i=0;i<nEndPos.length-1;i++) 3S;>ki4(0  
{ muW`pm  
nEndPos = nStartPos[i+1]; Bi'I18<  
} ,oC={^l{  
nEndPos[nEndPos.length-1] = nFileLength; 5hlJbWJa  
} 9NJ=~Ub-  
} ?aP1  
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//启动子线程 ]!n*V
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; hz&^_G6`  
for(int i=0;i<nStartPos.length;i++) Y+|L3'H  
{ r!"CH5dT  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), U{
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;4+qPWwq8W  
nStartPos,nEndPos,i); ]H@v  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r0rJ.}!  
fileSplitterFetch.start(); &f (sfM_n  
} x0}<n99qE  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |:!EHFr  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Fcu
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %:yHMEG]'  
nEndPos = " + nFileLength); ;}UIj{sj*  
// fileSplitterFetch[nPos.length-1].start(); 3(oZZz  
" 8~f  
V#n?&-{V  
//等待子线程结束 1^n5CI|7u  
//int count = 0; iKP\/LR<n  
//是否结束while循环 pZni,<Q  
boolean breakWhile = false; S
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while(!bStop) Fm-q=3  
{ sDz)_;;%  
write_nPos(); r4]hS`X~%  
Utility.sleep(500); mtiO7w"M\7  
breakWhile = true; 'lQ  
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for(int i=0;i<nStartPos.length;i++) hlABu)B'1  
{ j TB<E=WC  
if(!fileSplitterFetch.bDownOver) wN/*|?`Z  
{ V1UUAvN7s  
breakWhile = false; *!wO:<-  
break; b |o`Q7Hj  
} =Qjw.6@  
} I_jM-/3b  
if(breakWhile) < e7<t9  
break; FVvv  
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//count++; B6Wq/fl/  
//if(count>4) l&e5_]+%  
// siteStop(); Sm*Jysy`  
} qCxD{-9x{  
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System.err.println("文件下载结束！"); QTrlQH&p  
} jx5
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catch(Exception e){e.printStackTrace ();} ]IbPWBX  
} 'Z(MV&  
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//获得文件长度 .5#tB*H  
public long getFileSize() |R &3/bEr  
{ 6S&

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int nFileLength = -1; S,)|~#5x  
try{ s&QBFyKtJ  
URL url = new URL(siteInfoBean.getSSiteURL()); "Wn?8vR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w$U/;C  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5M\=+5wB  
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int responseCode=httpConnection.getResponseCode(); 5qtmb4R~  
if(responseCode>=400) EV?47\~  
{
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processErrorCode(responseCode); M~{P',l*  
return -2; //-2 represent access is error s2kZZP8-  
} >fZ/09&3  
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String sHeader; X\$W'^np  
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for(int i=1;;i++) sY;gh`4h  
{ l SV
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); :?:j$ =nWN  
//Utility.log(in.readLine()); ,O&PLr8cJ?  
sHeader=httpConnection.getHeaderFieldKey(i); ^ yukn*L  
if(sHeader!=null) a+>W  
{ N;`[R>Z~  
if(sHeader.equals("Content-Length")) K9qEi{[  
{ Ignv|TYG  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); U3j~}H.D1  
break; gHh.|PysW  
} @;n$caw  
} VgZaDd;  
else 5q_OuZ/6  
break; Uh|__DUkh  
} r)#"$Sm  
} )`+@j
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catch(IOException e){e.printStackTrace ();} 4{pemqS*  
catch(Exception e){e.printStackTrace ();} j_a~)o-p  
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Utility.log(nFileLength); $Z%aGc*  
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return nFileLength; X,Q=n2X?3  
} 
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//保存下载信息（文件指针位置） "O*W]e  
private void write_nPos() ATmqq)\s  
{ h^_taAdS`  
try{ k]/6/s\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); SX=0f^  
output.writeInt(nStartPos.length); <sCq x/L  
for(int i=0;i<nStartPos.length;i++) !E:Vn *k;  
{ ,fG_'3w
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// output.writeLong(nPos); 4bFVyv  
output.writeLong(fileSplitterFetch.nStartPos); R5;eR(24G  
output.writeLong(fileSplitterFetch.nEndPos); F/od,w9_  
} ~q T1<k  
output.close(); yDyeP{  
} lQ<n dt~  
catch(IOException e){e.printStackTrace ();} zI:5I@ X  
catch(Exception e){e.printStackTrace ();} d,rEEc Y  
} *J
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//读取保存的下载信息（文件指针位置） .SV3<)  
private void read_nPos() X@AkA9'fq  
{ s^?sJUj  
try{ qD%&\ZT  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -b>O4_N  
int nCount = input.readInt(); n`T[eb~  
nStartPos = new long[nCount]; NDa|.,  
nEndPos = new long[nCount]; 0G\
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for(int i=0;i<nStartPos.length;i++) KJ^GUqVl  
{ =U7D}n hS-  
nStartPos = input.readLong(); 9H%xZ(`vN  
nEndPos = input.readLong(); Y$$?8xr ~  
} 2l(j 4~g  
input.close(); AW&s-b%P  
} 8(/f!~  
catch(IOException e){e.printStackTrace ();} P~ pbx  
catch(Exception e){e.printStackTrace ();} 07"Oj9NlA  
} W]}V<S$  
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private void processErrorCode(int nErrorCode) $~@096`QL<  
{ PW//8
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System.err.println("Error Code : " + nErrorCode); >Wit"p  
} ZFuJ2 :  
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//停止文件下载 6`";)T[G9  
public void siteStop() hGo|2@sc  
{ f uNXY-;  
bStop = true; 34^Cfh  
for(int i=0;i<nStartPos.length;i++) 9c %Tv  
fileSplitterFetch.splitterStop(); ^t ldm7{_  
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} {5IG3'  
} Y4qyy\}  
//负责部分文件的抓取 wBHDof xX  
**FileSplitterFetch.java [gdPHXs  
*/ BI^]juH-c  
package NetFox; Uu:v4a  
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import java.io.*; (4f9
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import java.net.*; "3oU (RA  
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public class FileSplitterFetch extends Thread { 'I>#0VRr  
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String sURL; //File URL Bg0cC  
long nStartPos; //File Snippet Start Position _";pk _  
long nEndPos; //File Snippet End Position xy3
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int nThreadID; //Thread's ID b{>dOI*.}  
boolean bDownOver = false; //Downing is over 7<o;3gR7Kj  
boolean bStop = false; //Stop identical fO(S+}  
FileAccessI fileAccessI = null; //File Access interface <slq1  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException P2JRsZ.  
{ j4r,_lH^r  
this.sURL = sURL; =?Md&%j  
this.nStartPos = nStart; P}QbxkS 8  
this.nEndPos = nEnd; 9ufs6z  
nThreadID = id; h:sG23@=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 rK)  
} pP,bW~rk  
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public void run() Ht^2)~e~:  
{ M #&L@fg!  
while(nStartPos < nEndPos && !bStop) c!^}!32j)  
{ \o)4m[oF  
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try{ swL|Ff`$  
URL url = new URL(sURL); k\%v;3nBK  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <uwCP4E  
httpConnection.setRequestProperty("User-Agent","NetFox"); O9)}:++T  
String sProperty = "bytes="+nStartPos+"-"; FNEmGz/4  
httpConnection.setRequestProperty("RANGE",sProperty); ymX,k|lh  
Utility.log(sProperty); wR$8drn]Rq  
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InputStream input = httpConnection.getInputStream(); !z 5d+ M  
//logResponseHead(httpConnection); wu&7#![,  
*v/*_6
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byte[] b = new byte[1024]; oa !P]r  
int nRead; {=7i}xY]T  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1^^D :tt  
{ S Tk#hhx  
nStartPos += fileAccessI.write(b,0,nRead); JHH&@Cn  
//if(nThreadID == 1) T=dvc}  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >v,j;[(  
} (r\h dLX  
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Utility.log("Thread " + nThreadID + " is over!"); =W*`HV-w  
bDownOver = true; @0'|Uygn  
//nPos = fileAccessI.write (b,0,nRead); *7ro [  
} ?} tQaj  
catch(Exception e){e.printStackTrace ();} {K8T5zrV  
} p;=(-4\V}  
} (k&aD2PH  
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//打印回应的头信息 jloyJ@ck  
public void logResponseHead(HttpURLConnection con) M[_I16s  
{ BmXGk  
for(int i=1;;i++) ]_8 \g`"u  
{ 3y,?>-  
String header=con.getHeaderFieldKey(i); 7'uc;5:  
if(header!=null) Uk\U*\.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); cSk}53  
Utility.log(header+" : "+con.getHeaderField(header)); ", )  
else {?hjx+v[  
break; 0%+k>(@R  
} r'\TS U5!  
} ".D +# 2Kl  
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public void splitterStop() Ntiz-qW  
{ x)L@xQ  
bStop = true; IyP].g1"U  
} X&Lt?e,&  
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} rSn7(3e4^  
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/* j]&{ @Y  
**FileAccess.java G].KJ5,y  
*//文件访问(定位，写) 'VEpVo/  
package NetFox; {hz:[  
import java.io.*; o7zfD94I  
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public class FileAccessI implements Serializable{ 9To6Rc;  
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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 ||aU>Wj4  
RandomAccessFile oSavedFile; >,3 3Jx  
long nPos; xK3;/!\`  
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public FileAccessI() throws IOException 1[^d8!U  
{ dZmq  
this("",0); y>8?RX8  
} ,qB081hPG  
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public FileAccessI(String sName,long nPos) throws IOException y{JkY\g  
{ F}>`3//u  
oSavedFile = new RandomAccessFile(sName,"rw"); BYU.ptiJJ  
this.nPos = nPos; q=6Y2Q  
oSavedFile.seek(nPos); 7i.aZ2a%  
} sSUd;BYf  
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qa6~N3*  
public synchronized int write(byte[] b,int nStart,int nLen) f6nltZ  
{ cDg27xOUi  
int n = -1; v<1;1m  
try{ NO^(D+9  
oSavedFile.write(b,nStart,nLen); QUf_fe!,|  
n = nLen; gp=0;#4 4  
} T*m21<  
catch(IOException e) p<4':s;*  
{ ~vmY2h\  
e.printStackTrace (); dp_q:P4;B  
} ZV;yXLx|  
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return n; uk,f}Xc  
} ] ?(=rm9u  
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} . {I7sUQ  
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/* Ry C7  
**SiteInfoBean.java bxs@_fH  
*/ z61 o6mb  
package NetFox; AI2CfH#:C  
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public class SiteInfoBean { _qV_(TpS+  
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private String sSiteURL; //Site's URL yrw!b\  
private String sFilePath; //Saved File's Path U*cj'`eqC  
private String sFileName; //Saved File's Name _wBPn6gg`  
private int nSplitter; //Count of Splited Downloading File ,P^"X5$  
&D:88   
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public SiteInfoBean() v&Kw 3!X#E  
{//nSplitter的缺省值为5 'PZJ{8=  
//default value of nSplitter is 5 Gx m"HC
  
this("","","",5); `|R{^Sk1o  
} *d(Dk*(  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) qcqf9g  
{ Ch3##-  
sSiteURL= sURL;  l}JVRU{  
sFilePath = sPath; c}A^0,"z>  
sFileName = sName; ]#`bYh^y  
this.nSplitter = nSpiltter; [{YV<kN  
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} AWw'pgTQX  
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public String getSSiteURL() >|<6s],v  
{ J{H475GqiT  
return sSiteURL; H_9~gi  
} sB $!X@  
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public void setSSiteURL(String value) \-^3Pe,  
{ p?Y1^/   
sSiteURL = value; c8(.bmvF  
} grZN.zTO  
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public String getSFilePath() M:ttzsd  
{ U9Sp$$
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return sFilePath; #VLTx!5o  
} f.!cR3XgV  
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public void setSFilePath(String value) }RXm=ArN  
{ "F=O   
sFilePath = value; L;Nm"[`  
} 8ED6C"6  
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public String getSFileName() (|W@p\Q  
{ J:t1W=lJ3  
return sFileName; d35,[  
} F*QGzbv)  
0 j6/H?OT  
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public void setSFileName(String value) m/<7FU8  
{ d>2>mT$U  
sFileName = value; 7Kfh:0Ihhy  
} 5@?P8  
}=NjFK_6  
<}G7#xg  
public int getNSplitter() n<?:!f`  
{ g^=p)h3  
return nSplitter; iJU]|t  
} XSXS;Fh)  
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public void setNSplitter(int nCount) /.P*%'g  
{ '(;`t1V8k  
nSplitter = nCount; 3#
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} 0m!+gZ@  
} .^ so
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/* (z\@T`6`  
**Utility.java L'.7V ~b{  
*/ Eb[*nWF=  
package NetFox; PE0A`  
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public class Utility { lo Oh }y+  
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public Utility() o/ ozX4C  
{ xM'bb5  
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|#>\GU=!  
} IOtSAf  
{%*,KB>b  
//线程睡眠 1TJ2HO=Y  
public static void sleep(int nSecond) :2vk vLM  
{ )l~:Puvh  
try{ _SY4Qs`d  
Thread.sleep(nSecond);
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} =Q>'?w>  
catch(Exception e) INZsDM 9  
{ LB1LQ0M  
e.printStackTrace (); W1fEUVj  
} j#hFx+S  
} J'jwRn  
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//日志 R7pdwKD  
public static void log(String sMsg) |uf{:U)  
{ &NM.}f  
System.err.println(sMsg); $dIu${lu  
} yhxen  
}8`W%_Yk  
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public static void log(int sMsg) kK\G+{z?  
{ 2:3-mWE  
System.err.println(sMsg); LhO%^`vu
 
} .LMOm
c=(  
} F<H[-k*t/  
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/* 0se0AcrW  
**TestMethod.java Z1Y/2MVSb  
*/ !'scOWWn  
package NetFox; ?'SHt9b3|  
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public class TestMethod { \A "_|Yg  
" ,k(*  
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public TestMethod() {P/ sxh:e  
{ ///xx/weblogic60b2_win.exe
V;}kgWc1  
try{ V}=%/OY?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); v_=xN^R  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }#'I,?_k  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &ed&2t`Y  
fileFetch.start(); bT93R8yp  
} ' b?' u  
catch(Exception e){e.printStackTrace ();} Em6P6D>S>,  
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} xAlyik  
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public static void main(String[] args) 5~8FZ-x  
{ <=O/_Iu(  
new TestMethod(); B"; >
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} '?$N.lj$d  
} /w[B,_ZKTk  
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