http断点续传简单实现（java)

/* G/mXq-  
**SiteFileFetch.java W"3ph6[eW  
*/ "x /OIf  
package NetFox; _Y[bMuUb=  
import java.io.*; [66!bM&  
import java.net.*; uXq. ]ub  
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public class SiteFileFetch extends Thread { ,'iE;o{Tu  


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SiteInfoBean siteInfoBean = null; //文件信息Bean .-X8J t  
long[] nStartPos; //开始位置 :U(A;U1,  
long[] nEndPos; //结束位置 ;
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 %9RF  
long nFileLength; //文件长度 !#"zTj  
boolean bFirst = true; //是否第一次取文件 =4!e&o  
boolean bStop = false; //停止标志 C\/L v.  
File tmpFile; //文件下载的临时信息 9!DQ~k%  
DataOutputStream output; //输出到文件的输出流 H]jhAf<h  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） wg]LVW}  
public SiteFileFetch(SiteInfoBean bean) throws IOException @jlw_ob2g  
{ O5t[  
siteInfoBean = bean; O s.4)  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 4
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5lT*hF  
if(tmpFile.exists ()) 4X(H;  
{ CC^'@~)?  
bFirst = false; |qZ1|  
read_nPos(); AZ}Xj>=  
} Bng@-#`/  
else yEj^=pw  
{ `I5wV/%ib  
nStartPos = new long[bean.getNSplitter()]; [,KXze_m  
nEndPos = new long[bean.getNSplitter()]; (DP &B%Sf  
} \K<QmK  
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} Nm>A'bLM  
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public void run() !o[7wKrXb  
{ d6sye^P  
//获得文件长度 we?76t:-  
//分割文件 VgC2+APg  
//实例FileSplitterFetch p`#R<K  
//启动FileSplitterFetch线程 M|(Q0 _8  
//等待子线程返回 td3D=Y  
try{ VEw"  
if(bFirst) _aMPa+D=P  
{ Yr=Y@~ XL  
nFileLength = getFileSize(); h@]XBv  
if(nFileLength == -1) Bv%GJ
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{ l/ ;  
System.err.println("File Length is not known!"); "4,?uPi  
} Y.ToIka{  
else if(nFileLength == -2) A^EE32kbm  
{ SrK<fAkx  
System.err.println("File is not access!"); ye? 'Ze  
} c>~*/%+  
else ,V:SN~P66+  
{ A;|D:;x3G  
for(int i=0;i<nStartPos.length;i++) 'xg Lt(  
{ %(G* ,  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); v(D;PS3r 7  
} YNj`W
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for(int i=0;i<nEndPos.length-1;i++) {9aE5kR  
{ =;&yd';k  
nEndPos = nStartPos[i+1]; pK'V9fD5J  
} (%W&4a1di  
nEndPos[nEndPos.length-1] = nFileLength; ^7KH _t8
 
} M8b;d}XL  
} dIBE!4 V[  
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//启动子线程 EeRX+BM,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; c[1oww  
for(int i=0;i<nStartPos.length;i++) V0XvJ  
{ V2|aN<Sx<  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6s/&BR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ?+a,m# Yx  
nStartPos,nEndPos,i); !|S43i&p  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); VsE9H]v   
fileSplitterFetch.start(); sCb=5uI  
} =k0_eX0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~-J]W-n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Z//+Gw<'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", sAD}#Zw$  
nEndPos = " + nFileLength); |CZ@te)>  
// fileSplitterFetch[nPos.length-1].start(); vv+z'(l  
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//等待子线程结束 %k?U9pj^  
//int count = 0; ;Q*or2"!  
//是否结束while循环 %pd,%pg  
boolean breakWhile = false; Z>Wg*sZy)  
4 bH^":i(  
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while(!bStop) 364`IC( a  
{ 9g"2^^wD  
write_nPos(); i||]V*5n  
Utility.sleep(500); )MchsuF<  
breakWhile = true; }n2M G  
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for(int i=0;i<nStartPos.length;i++) emPM4iG?!  
{ B1C-J/J  
if(!fileSplitterFetch.bDownOver) (/j/>9iro  
{ O7<]U_"I  
breakWhile = false; .1Al<OLL  
break; {Um)15K  
} wlk4*4dKn  
} L(-b@Joh  
if(breakWhile) 5Qn '  
break; ssRbhlD/*1  
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//count++; OAkZKG|  
//if(count>4) ~%=MpQ3  
// siteStop(); QYjsDL><  
} <Fc;_GG  
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System.err.println("文件下载结束！"); _i|t Y4L  
} ( _)jkI \  
catch(Exception e){e.printStackTrace ();} J|bd)0  
}
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//获得文件长度 ,>-< (Qi  
public long getFileSize() ?_vakJ )  
{ 2Yn <2U/^R  
int nFileLength = -1; DN~nk  
try{ .=;3d~.]  
URL url = new URL(siteInfoBean.getSSiteURL()); tlqiXh<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -~30)J=e`  
httpConnection.setRequestProperty("User-Agent","NetFox"); NzSoqh{R  
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int responseCode=httpConnection.getResponseCode(); V7P&%oz{C  
if(responseCode>=400) s1NKLt  
{ FUjl8b-|  
processErrorCode(responseCode); W7\f1}]H  
return -2; //-2 represent access is error !&/{E [  
} *HO}~A%Lx  
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String sHeader; o.G!7  
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for(int i=1;;i++) ie\"$i.98H  
{ $[&*Bj11Yg  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); G<f@#[$'  
//Utility.log(in.readLine()); af+IP_6 .  
sHeader=httpConnection.getHeaderFieldKey(i); 80/F7q'tn  
if(sHeader!=null) FCuB\Q  
{ \r,Q1n?7  
if(sHeader.equals("Content-Length")) 2.zsCu4lj.  
{ +W\f(/q0  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /8g^T")  
break;  Q&g^c2  
} [[F
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} pDcjwlA%  
else /[)qEl2]K  
break; 5sJJGv#6  
} rIhl.5Y  
} i2(1ki/|O  
catch(IOException e){e.printStackTrace ();} k_q0Q;6w!l  
catch(Exception e){e.printStackTrace ();} `gb5"`EZ  
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Utility.log(nFileLength); .wu xoq  
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return nFileLength; :1^R9yWA4  
} A"D,Kg S  
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//保存下载信息（文件指针位置） Upd3-2kr&J  
private void write_nPos() #KXa&C  
{ w1"nffhO  
try{ 8C~]
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output = new DataOutputStream(new FileOutputStream(tmpFile)); xA$ns
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output.writeInt(nStartPos.length); l
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for(int i=0;i<nStartPos.length;i++) ~-
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{ I_rO!  
// output.writeLong(nPos); fCtPu08{Z  
output.writeLong(fileSplitterFetch.nStartPos); \y)  
output.writeLong(fileSplitterFetch.nEndPos); J@X'PG< 6B  
} uVDa^+
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output.close(); mB9r3[  
} O1*NzY0Y%-  
catch(IOException e){e.printStackTrace ();} BWuqo  
catch(Exception e){e.printStackTrace ();} /_Z652@  
} r*_ZJ*h[  
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//读取保存的下载信息（文件指针位置） "D=P8X&vs  
private void read_nPos() '-b*EZU8t  
{ $.v5~UGb{\  
try{ $K'|0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); UHxE)]J  
int nCount = input.readInt(); MR<;i2p  
nStartPos = new long[nCount]; a5!Fv54  
nEndPos = new long[nCount]; $3uKw!z  
for(int i=0;i<nStartPos.length;i++) MFm"G  
{ R&';Oro  
nStartPos = input.readLong(); hQHnwr  
nEndPos = input.readLong(); xD[Gq%  
} /iV}HV0  
input.close(); hcbv;[bG  
} A\#P*+k0  
catch(IOException e){e.printStackTrace ();} S'B|>!z@  
catch(Exception e){e.printStackTrace ();} Xo*%/0q'  
} _({A\}Q|  
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private void processErrorCode(int nErrorCode) _}VloiY  
{ ?Wt$6{)  
System.err.println("Error Code : " + nErrorCode); pd8Nke  
} JEgx@};O  
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>P $;79<  
//停止文件下载 /<8N\_wh  
public void siteStop() `zt_7MD  
{ Vy,^)]  
bStop = true; O Wj@<N  
for(int i=0;i<nStartPos.length;i++) k{$ ao  
fileSplitterFetch.splitterStop(); f'{]"^e=  
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} S^<g_q  
} L%c0Z@[~  
//负责部分文件的抓取 }~h(w^t  
**FileSplitterFetch.java 'fNKlPMv4D  
*/ <rL/B k  
package NetFox; "0k8IVwp  
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import java.io.*; %8M)2?E  
import java.net.*; ^ Dt#$Z  
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public class FileSplitterFetch extends Thread { )){9&5,0:  
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String sURL; //File URL [j:[  
long nStartPos; //File Snippet Start Position (nab
 
long nEndPos; //File Snippet End Position [wB9s{CX  
int nThreadID; //Thread's ID ]UG*r%9  
boolean bDownOver = false; //Downing is over (%:>T Q(  
boolean bStop = false; //Stop identical JHJ~X v  
FileAccessI fileAccessI = null; //File Access interface Q\,o:ZU_  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 5`RiS]IO]  
{ [e4]"v`N  
this.sURL = sURL; ? j 9|5*  
this.nStartPos = nStart; rJInj>
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this.nEndPos = nEnd; eBO@7F$  
nThreadID = id; *d',Vuv&[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 d'Axum@  
} u}|%@=xn  
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@(i!YL  
public void run() {?}*1,I  
{ A?T<",bO
 
while(nStartPos < nEndPos && !bStop) FsGlJ  
{ ^p/O
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try{ 1uk0d`JL  
URL url = new URL(sURL); *79m^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?}Lg)EFH  
httpConnection.setRequestProperty("User-Agent","NetFox"); `3'0I/d"z  
String sProperty = "bytes="+nStartPos+"-"; ~b|`'kU  
httpConnection.setRequestProperty("RANGE",sProperty); ]}6w#)]"  
Utility.log(sProperty); 08m;{+|vY  
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InputStream input = httpConnection.getInputStream(); %D`,k*X  
//logResponseHead(httpConnection); :g\rQazxO  
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byte[] b = new byte[1024]; kzS=g|_  
int nRead; leiW4Fj  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) N9rBW
 
{ M8b4NF_&  
nStartPos += fileAccessI.write(b,0,nRead); @v*/R%rv t  
//if(nThreadID == 1) =_8Tp~j  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `j9$T:`  
} m3g2b _;  
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Utility.log("Thread " + nThreadID + " is over!"); x)_@9ldYv  
bDownOver = true; m%8qZzqk  
//nPos = fileAccessI.write (b,0,nRead); ;!T{%-tP  
} ?n\*,{9  
catch(Exception e){e.printStackTrace ();} @E53JKYhY  
} P~FUS%39"o  
} 1Fi86  
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//打印回应的头信息 8Z2.`(3c[  
public void logResponseHead(HttpURLConnection con) l**;k+hw  
{ RP`2)/sMT  
for(int i=1;;i++) p=QYc)3F  
{ <vbIp&  
String header=con.getHeaderFieldKey(i); %AnW~v  
if(header!=null) 2`=6%s  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :;!\vfZbU  
Utility.log(header+" : "+con.getHeaderField(header)); 'iLH `WE  
else {hO`6mr&t  
break; H2-28XG
c  
} @lUlY2  
} 3v!~cC~cI  
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public void splitterStop() v1.q$ f^(  
{ vG2b:[W  
bStop = true; <39!G7ny  
} lKEa)KF[  
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} bO/*2oau  
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/* C+MSVc  
**FileAccess.java X
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*//文件访问(定位，写) wp.TfKxw  
package NetFox; G;oFTP>o  
import java.io.*; ]PNowS\  
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public class FileAccessI implements Serializable{ xkA2g[  
.]}N55M  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 DjW$?>  
RandomAccessFile oSavedFile; \`xkp[C  
long nPos; *
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public FileAccessI() throws IOException 1:= `Y@.S  
{ w9#R'  
this("",0); xnq><4  
} qA/bg  
^i:\@VA:  
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public FileAccessI(String sName,long nPos) throws IOException cQFR]i  
{ twk&-:'  
oSavedFile = new RandomAccessFile(sName,"rw"); H*W):j}8  
this.nPos = nPos; 0D)`2W  
oSavedFile.seek(nPos); Z]-WFU_ N  
} s!6=|SS7  
p#_[  
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public synchronized int write(byte[] b,int nStart,int nLen) 8t.dPy<  
{ LI:T
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int n = -1; ur2!#bU9  
try{ e4qj .b  
oSavedFile.write(b,nStart,nLen); ibF#$&!  
n = nLen; En9R>A;`  
} iY.eJlfH  
catch(IOException e) KC&`x|  
{ +|C[-W7Sw  
e.printStackTrace (); :J(sXKr[C  
} {&nV4
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return n; zd`=Ih2Wx  
} GzdgL"M[  
 ?B4#f!X  
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} =2oUZjA  
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/* EE%s<_k`  
**SiteInfoBean.java M g!ra"  
*/ Y5jYm
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package NetFox; If}lJ6jZ  
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public class SiteInfoBean { U4_"aT>My  
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private String sSiteURL; //Site's URL  |R'i:=  
private String sFilePath; //Saved File's Path ]M4NpUM  
private String sFileName; //Saved File's Name ~Ob8i1S>  
private int nSplitter; //Count of Splited Downloading File v'nHFC+p  
if@W ]%  
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public SiteInfoBean() 5a$$95oL  
{//nSplitter的缺省值为5 PqhlXqX9  
//default value of nSplitter is 5 VBx,iuaw  
this("","","",5); 8t9aHla  
} Y(GW0\<  
SLA#= K  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ${e&A^h  
{ ~R!gJTO9  
sSiteURL= sURL;
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sFilePath = sPath; ;?8Iys#  
sFileName = sName; ~N[|bPRmhE  
this.nSplitter = nSpiltter; 3zb)"\(R  
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} zH+<bEo=1=  
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public String getSSiteURL() [s %\.y(q  
{
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return sSiteURL; 6{^*JC5nj  
} 3o7xN=N  
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public void setSSiteURL(String value) :
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{ 3"B+xbe=  
sSiteURL = value; ' C6:e?R  
} U$$3'n  
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public String getSFilePath() nCB[4  
{ 36i_D6  
return sFilePath; ]n1D1  
} 7xR|_+%~K  
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public void setSFilePath(String value) s7Qyfe&>  
{ n +dJc  
sFilePath = value; 1Q_ ``.M  
} 7NUenCdc  
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public String getSFileName() q @*UUj@  
{ eHROBxH&  
return sFileName; WnO DDr  
} +cw{aI`a8  
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public void setSFileName(String value) C[W5d~
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{ YRu%j4Tx  
sFileName = value; \ >(zunL  
} FP@A;/c  
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}9FD/  
public int getNSplitter() o5V`'[c  
{ x/[8Wi,yB  
return nSplitter; K5+!(5V~  
} %)dI2 J^Xf  
(mY(\mu}  
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public void setNSplitter(int nCount) e Ri!\Fx  
{ _jk|}IB;X  
nSplitter = nCount; 3v G  
} o[2Y;kP3*P  
} 1y(iE C  
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|/2LWc?  
/* {!g?d<*  
**Utility.java Xv]*;Bq:SK  
*/ hX %s]"  
package NetFox; TR|;,A[%v#  
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public class Utility { )e#fj+>x)  
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7ia"
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public Utility() ]P JH'=  
{ I_K[!4~Kn  
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} [gTQ-  
-wBnwn-  
//线程睡眠 Y<de9Z@  
public static void sleep(int nSecond) IZ|c<#r6  
{ dV$3u"9  
try{ nO-d"S*  
Thread.sleep(nSecond); 2}GKHC  
} G)jG!`I  
catch(Exception e) 1k0^6gE|  
{ xqU^I5Z  
e.printStackTrace (); -fhAtxkg  
} jDFp31_X  
} QZqpF9Eu  
ZyZl\\8U  
//日志 KhLg*EL  
public static void log(String sMsg) D1"1MUSod  
{ S|s3}]g9  
System.err.println(sMsg); jw%fN!?  
} (=6P]~,  
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public static void log(int sMsg) yo'q[YtP'  
{ 5 1v r^  
System.err.println(sMsg); DIL)7K4  
} D[+|^,^>  
} =lYvj  
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tbL1g{Dz,  
/* ks)fQFSbu  
**TestMethod.java LqM
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*/ 7 _X&5ni  
package NetFox; #tCIuQ,  
4+BrTGp  
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public class TestMethod { zUvB0\{q  
Bb$S^F(Xq  
mxtlr)  
public TestMethod() ]Fb8.q5(Y  
{ ///xx/weblogic60b2_win.exe 8/Lu'rI  
try{ R:SIs
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [^cs~ n4  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ")fOup@ ^a  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?+5" %4o  
fileFetch.start(); V6A5(-%`y  
} +#&el//
 
catch(Exception e){e.printStackTrace ();} 1Kp?bwh"u  
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} l6r%nHP@  
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public static void main(String[] args) nhB^Xr=  
{ E&}H\zt#  
new TestMethod(); $Ui]hA-:?y  
} {jq^hM!TEy  
} 9aW8wYL~b  
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