http断点续传简单实现（java)

/* =C}<0<"iF  
**SiteFileFetch.java  K8we*  
*/ ]@g$<&  
package NetFox; h2*&>Mc  
import java.io.*; QAw,XZ.K^  
import java.net.*; lt"*y.%@b  
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public class SiteFileFetch extends Thread { :cz]8~i\  
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SiteInfoBean siteInfoBean = null; //文件信息Bean
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long[] nStartPos; //开始位置 .OUE'5e p  
long[] nEndPos; //结束位置 )eyxAg  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 (KU@hp-\  
long nFileLength; //文件长度 VAzJclB  
boolean bFirst = true; //是否第一次取文件 )SLs  [  
boolean bStop = false; //停止标志 +Enff0 =+  
File tmpFile; //文件下载的临时信息 &g {_.n,  
DataOutputStream output; //输出到文件的输出流 W.<<azi  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） (`*wiu+i  
public SiteFileFetch(SiteInfoBean bean) throws IOException 0_.hU^fP  
{ tfQq3#  
siteInfoBean = bean; (HxF\#r?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^%^0x'"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 9jO+ew  
if(tmpFile.exists ()) U$Z}<8  
{ oa7Hx<Y  
bFirst = false; (`xnA~BN  
read_nPos(); dkC/ ?R  
} B\yq%m  
else znRhQ+8;!  
{ g>CQO,s;w  
nStartPos = new long[bean.getNSplitter()]; M*uG`Eo&  
nEndPos = new long[bean.getNSplitter()]; hgltD8,  
} Puh&F< B  
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} oPBjsQ  
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public void run() gV;GC{pY  
{ '+wTrW m~j  
//获得文件长度 bc-)y3gHU  
//分割文件 vL0Ol-Vt  
//实例FileSplitterFetch :Aw VeX@  
//启动FileSplitterFetch线程 xb\:H@92  
//等待子线程返回 *
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try{ zBfBYhS-  
if(bFirst) [t
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{ \:7EKzQ  
nFileLength = getFileSize(); //|Vj | =  
if(nFileLength == -1) Hq$|j,&?  
{ 2T9Z{v  
System.err.println("File Length is not known!"); vS#]RW&j  
} RJD3o_("K  
else if(nFileLength == -2) U4JN
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{ ] fB{  
System.err.println("File is not access!"); GAKJc\o  
} <rs]@J'p  
else ks$G6WC  
{ P $S P4F  
for(int i=0;i<nStartPos.length;i++) IF1}}[Ht  
{ "N_?yA#(j  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); tAUMSr|?  
} nc)`ISI  
for(int i=0;i<nEndPos.length-1;i++) H_^c K  
{ 7O#>N}|  
nEndPos = nStartPos[i+1]; t,_[nu(~8%  
} r.5F^   
nEndPos[nEndPos.length-1] = nFileLength; VXS9E383  
} 3}+ \&[  
} iqeGy&F-  
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//启动子线程 )
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @T"385>  
for(int i=0;i<nStartPos.length;i++) ^da-R;o]  
{ (n\ cs$  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ";]m]PRAam  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), QTH yH  
nStartPos,nEndPos,i); ?%(*bRV -  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); b8&9pLl  
fileSplitterFetch.start(); 6s;x@g]  
} |(5=4j]  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <*P1Sd.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); O/Vue  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "/5b3^a  
nEndPos = " + nFileLength); XJ9>a-{  
// fileSplitterFetch[nPos.length-1].start(); 2Z~ofrj  
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//等待子线程结束 MZ'HMYed   
//int count = 0; ZUycJ-[  
//是否结束while循环 [aC(Ga}  
boolean breakWhile = false; cf9y0  
{;U:0BPI3  
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while(!bStop) \=)h6AG  
{ (!s[~O6  
write_nPos(); jk@]d5  
Utility.sleep(500); d<o  
breakWhile = true; ^_uzr}LE`  
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for(int i=0;i<nStartPos.length;i++) E2MpMR  
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if(!fileSplitterFetch.bDownOver) X9R-GT  
{  ~$B,K]  
breakWhile = false; eR CGr?e4  
break; P\JpE  
} f+&yc'[  
} |@RO&F  
if(breakWhile) n !QjptQ  
break; N@}U;x}  
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//count++; <IYt*vlm  
//if(count>4) 4.8,&{w<m  
// siteStop(); 0^=S:~G  
} 7Do)++t  
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System.err.println("文件下载结束！"); L<:ya  
} JsV#:  
catch(Exception e){e.printStackTrace ();} S<TfvQ\,"@  
} DQSv'!KFO  
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//获得文件长度 !E%!,  
public long getFileSize() (<12&=WxE  
{ w

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int nFileLength = -1; 4{|lzo'&  
try{
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URL url = new URL(siteInfoBean.getSSiteURL()); x;+,lP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xK/`XY  
httpConnection.setRequestProperty("User-Agent","NetFox"); wgrYZ^]  
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int responseCode=httpConnection.getResponseCode(); h
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if(responseCode>=400) ,#crtX  
{ sEoS|"  
processErrorCode(responseCode); -Jhf]  
return -2; //-2 represent access is error f*Kipgp  
} {1o=/&  
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String sHeader; ;BqX=X+#  
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for(int i=1;;i++) \sk,3b
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{ ;j$84o{  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); f:
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//Utility.log(in.readLine()); v#~,
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sHeader=httpConnection.getHeaderFieldKey(i); |A2.W8`o  
if(sHeader!=null) bH
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{ M?,;TJ7Gd  
if(sHeader.equals("Content-Length")) t*COzE  
{ [\VzI\vb  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 0xC!d-VIJ  
break; O&}07(  
} As"'KR  
} VR'w$mp  
else 62W3W1: W  
break; hJ|z8Sy@1  
} TqWvHZX  
} \UXQy{Ex  
catch(IOException e){e.printStackTrace ();} PgVM>_nHk  
catch(Exception e){e.printStackTrace ();} ar6Z?v$  
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Utility.log(nFileLength);
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return nFileLength; ;G w5
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} R)#"Ab Z'  
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//保存下载信息（文件指针位置） 3,pRmdC  
private void write_nPos() !XK p_v  
{ 5~\W!|j/  
try{ tvd/Y|bV=  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )&*&ZL0  
output.writeInt(nStartPos.length); Jap v<lV%  
for(int i=0;i<nStartPos.length;i++) W7.]V)$wM  
{ aUd633  
// output.writeLong(nPos); sUg7  
output.writeLong(fileSplitterFetch.nStartPos); 2hquE_1S[w  
output.writeLong(fileSplitterFetch.nEndPos); @.%ll n  
} W] RxRdY6[  
output.close(); _N<8!(|w  
} _mcD*V  
catch(IOException e){e.printStackTrace ();} 9;:
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catch(Exception e){e.printStackTrace ();} xEbcF+@  
} r> NgJf,  
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//读取保存的下载信息（文件指针位置） HIF.;ImG^  
private void read_nPos() {~Phc 2z  
{ %R}}1
 
try{ UA{A G;  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); `DEz ` D  
int nCount = input.readInt(); 3xeW!~  
nStartPos = new long[nCount]; zV%U4P)Dao  
nEndPos = new long[nCount]; T@X!vCjf6  
for(int i=0;i<nStartPos.length;i++) H=B8'N  
{ *r[PZ{D+  
nStartPos = input.readLong(); v\Q${6kEtx  
nEndPos = input.readLong(); (d@lG*K  
} 1;SWfKU?.  
input.close(); la f
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} 94H 6`  
catch(IOException e){e.printStackTrace ();} YrA#NTB_o  
catch(Exception e){e.printStackTrace ();} +
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} |',MgA  
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private void processErrorCode(int nErrorCode) xqIt?v2c  
{ mlX^5h'  
System.err.println("Error Code : " + nErrorCode); Fz-Bd*uS  
} -(~CZ  
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//停止文件下载 ]
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public void siteStop() Qb/qUUQO;0  
{ FhW\23OC  
bStop = true; 5v8_ji#l[  
for(int i=0;i<nStartPos.length;i++) |_Z(}% <o  
fileSplitterFetch.splitterStop(); MH1??vW  
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.#P'NF(5#  
} C}#JvNyQ  
} nT9B?P>  
//负责部分文件的抓取 vTN$SgzfCU  
**FileSplitterFetch.java 8IbHDDS
  
*/ v 6Tz7  
package NetFox; !\2Xr{f  
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import java.io.*; 9tWu>keu  
import java.net.*; iq
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public class FileSplitterFetch extends Thread { RoT}L#!!  
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String sURL; //File URL Q"S;r1 D  
long nStartPos; //File Snippet Start Position Az{Z=:(0  
long nEndPos; //File Snippet End Position l>Z"y\l=  
int nThreadID; //Thread's ID *?+E?AGe  
boolean bDownOver = false; //Downing is over UOi8>;k`  
boolean bStop = false; //Stop identical "}Vow^vb  
FileAccessI fileAccessI = null; //File Access interface >
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )u`q41!  
{ FTsvPLIv"  
this.sURL = sURL; EE=!Y NP]  
this.nStartPos = nStart; cE$7CSR  
this.nEndPos = nEnd; 0ERA(=w5  
nThreadID = id; QGs\af  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~s
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} 3[amCKel  
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public void run() [}}?a  
{ y}Oc^Fc  
while(nStartPos < nEndPos && !bStop) :>c33X
}  
{ F
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try{ HM/2/ /  
URL url = new URL(sURL); DKp+ nq$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); gi#bU  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9@/X;zO  
String sProperty = "bytes="+nStartPos+"-"; 6w|s1!Bl  
httpConnection.setRequestProperty("RANGE",sProperty); 0O,;[l  
Utility.log(sProperty); C0KFN  
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InputStream input = httpConnection.getInputStream(); FZn1$_Svr  
//logResponseHead(httpConnection); tW4
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byte[] b = new byte[1024]; VBQAkl?(}4  
int nRead; l"(PP3  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Gp \-AwE  
{ \Cu=Le^  
nStartPos += fileAccessI.write(b,0,nRead); k(pJVez  
//if(nThreadID == 1) 1;1;-4k7I  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A$N%deb  
} l"A/6r!Dp  
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Utility.log("Thread " + nThreadID + " is over!"); (3mL!1\  
bDownOver = true; M9A1 8d|  
//nPos = fileAccessI.write (b,0,nRead); zn 0y`9!n?  
} <Vk}U   
catch(Exception e){e.printStackTrace ();} @IsUY(Gu  
} ?4U4o<   
} S*=^I2;  
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//打印回应的头信息 oJ %Nt&q  
public void logResponseHead(HttpURLConnection con) m3Wc};yE*Q  
{ W{.:Cf9  
for(int i=1;;i++) =DfI^$Lr:  
{ zN!yOlp5  
String header=con.getHeaderFieldKey(i); rP'%f 6  
if(header!=null) HZ%V>88  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); wkGr}  
Utility.log(header+" : "+con.getHeaderField(header)); Iy49o!  
else %6 Av1cv  
break; s|H7;.3gp  
} &"JC
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} ^7/v[J<<  
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public void splitterStop() (kB  
{ ;
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bStop = true; .pWRV<25  
} b#p0s?*  
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} v~Dobk/n  
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/* 8
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**FileAccess.java 8tR6.09'  
*//文件访问(定位，写) J)B3o$  
package NetFox; rhQ+ylt8I  
import java.io.*; o.NU"$\?  
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public class FileAccessI implements Serializable{ -e(<Jd_=  
-s2)!Iko&  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 *Vq'%b9  
RandomAccessFile oSavedFile; ]Ss63Vd  
long nPos; l<uI-RX"  
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public FileAccessI() throws IOException 4cSs=|m?+  
{ !PGCoI  
this("",0); {CR`~)v&  
} ,"`3N2!Y}  
}NwmZw>_  
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public FileAccessI(String sName,long nPos) throws IOException Cj3Xp~  
{ 9 c9$
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oSavedFile = new RandomAccessFile(sName,"rw"); xj
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this.nPos = nPos; hz;SDaBA  
oSavedFile.seek(nPos); `Zo5!"'  
} jrN 5l1np  
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public synchronized int write(byte[] b,int nStart,int nLen) fgtwVji  
{ !gRU;ZQU_  
int n = -1; 89D`!`Ah]  
try{ 3{co.+  
oSavedFile.write(b,nStart,nLen); rwUhNth-Qh  
n = nLen; ^0>^5l'n  
} ,e1c,}  
catch(IOException e) uGXvP(Pg'  
{ SGZYDxFC@  
e.printStackTrace (); EJC}"%h  
} um]*nXIr  
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return n; W%ix|R^2]  
} g~K-'Nw  
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} CpN*1s})d  
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/* ~P,Z@|c4  
**SiteInfoBean.java sOWP0xY  
*/ wd|^m%  
package NetFox; 5?>Q[a.Ne  
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public class SiteInfoBean { *B&i`tq  
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private String sSiteURL; //Site's URL cqh1,h$sG  
private String sFilePath; //Saved File's Path =u9e5n  
private String sFileName; //Saved File's Name U/q"F<?.c  
private int nSplitter; //Count of Splited Downloading File $?kTS1I(  
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public SiteInfoBean() e'npa*.e  
{//nSplitter的缺省值为5 Gv)*[7  
//default value of nSplitter is 5 T`
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this("","","",5); hZ<FCY,/?  
} %:l\Vhhz  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 0[g5[?Vy  
{ ^|rzqXW  
sSiteURL= sURL; 9Y# vKb{>  
sFilePath = sPath; :WH0=Bieh  
sFileName = sName; w{;bvq%lY  
this.nSplitter = nSpiltter; fH
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} @&G %cW(  
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public String getSSiteURL() 0_>1CW+X  
{ pDr/8HEh  
return sSiteURL; kbz+6LcV  
} 2U+wiE|  
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public void setSSiteURL(String value) 8.`5"9Vh  
{ 0R+<^6^l)  
sSiteURL = value; I%{D5.du  
} g ?%]()E  
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public String getSFilePath() ^?0WE  
{ y3'K+?4  
return sFilePath; 1@]gBv<  
} Z79Y$d>G<E  
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public void setSFilePath(String value) [DSzhi]  
{ J72kjj&C  
sFilePath = value; 8+_e=_3R  
} ` NvJ  
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public String getSFileName() ;2eZa|M*q  
{ `@ Ont+  
return sFileName; ss7Z-A4z  
} ~m7?:(/lb  
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public void setSFileName(String value) 6O'B:5~
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{ eNt1P`2[  
sFileName = value; ^zS|O]Tx  
} ~ln96*)M;  
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public int getNSplitter() c$%I^f}'  
{ r<kqs,-~  
return nSplitter; ~rz%TDX0\  
} \9.@Tg8`  
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public void setNSplitter(int nCount) K&vqk/JW1  
{ %LdFS~  
nSplitter = nCount; y
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} AUkePp78  
} ,?!4P+ob  
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/* Ba|76OBRJ  
**Utility.java -f[95Z3}  
*/ M}F) P&Y  
package NetFox; #>\8m+h 9  
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public class Utility { cf1GA  
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public Utility() yy3-Xu4  
{ >9]i#So^  
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} :.EVvuXI  
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//线程睡眠 \>XkK<ye  
public static void sleep(int nSecond) 6~6*(s|]A  
{ 6Y
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try{ {f)"F;]V  
Thread.sleep(nSecond); j%s:d(H`  
} Kkds^v6  
catch(Exception e) 6oLq2Z8uP  
{ y{\K: 
 
e.printStackTrace (); ib)AC,LT  
} Bso3Z ^X.  
} 8(A+"H(  
( u}tUv3  
//日志 tqe8:\1yK  
public static void log(String sMsg) a)Ca:p  
{ B mxBbg  
System.err.println(sMsg); ! .|\}=[e  
} '&$xLZ8  
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public static void log(int sMsg) jPNm $Y1  
{ 4 '6HX#J  
System.err.println(sMsg); VM[Vhk[  
} %CiZ>`5n#  
} UDz#?ZWnd  
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P ".[=h  
/* ep2#a#&'  
**TestMethod.java t<2B3&o1  
*/ eE-@dU?  
package NetFox; $]yHk  
'hi.$G_R  
}EZd=_kAq~  
public class TestMethod { 9nPc>O$  
^.@BD4/RPt  
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public TestMethod() 2aUy1*aM  
{ ///xx/weblogic60b2_win.exe YAf`Fnmw  
try{ r/vRaOg>X  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); &*#- %<=1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ! uyC$8V*l  
SiteFileFetch fileFetch = new SiteFileFetch(bean); AGxG*KuZ  
fileFetch.start(); #2023Zo]  
} ,2YkQ/>  
catch(Exception e){e.printStackTrace ();} KDX34Fr1  
\{ui{8+G  
nZ 0rxx[V?  
} U&\8~h  
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public static void main(String[] args) ;:l\_b'Z}  
{ >~sAa+Oxi  
new TestMethod(); >)3[CU,  
} ,1+)qv#|i  
} $fwv'  
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