http断点续传简单实现（java)

/* ke6cZV5w  
**SiteFileFetch.java EQ`t:jc{  
*/ {zN_l!  
package NetFox; M{k
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import java.io.*;  eJ\j{-  
import java.net.*; tS\NO@E_Jh  
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public class SiteFileFetch extends Thread { "9T`3cM0  
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SiteInfoBean siteInfoBean = null; //文件信息Bean w3cK: C0  
long[] nStartPos; //开始位置 5Cyjq0+  
long[] nEndPos; //结束位置 ?{P6AF-xcf  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Lj1 @yokB  
long nFileLength; //文件长度 T[=cKYp8\  
boolean bFirst = true; //是否第一次取文件 6zZR:ej  
boolean bStop = false; //停止标志 BiCa "  
File tmpFile; //文件下载的临时信息 l5nDt$Ex  
DataOutputStream output; //输出到文件的输出流 1e| M6*  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） R'HA>?D  
public SiteFileFetch(SiteInfoBean bean) throws IOException s3
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{ &+iW:  
siteInfoBean = bean; O9&:(2'f  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); j;'Wf[V  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); :R\v# )C  
if(tmpFile.exists ()) GQBN-Qv  
{ F76h  
bFirst = false; &V{,D))6[  
read_nPos(); l#.,wOO{  
} ;7*@Gf}R  
else eH*b-H[  
{ Hxi=\2-  
nStartPos = new long[bean.getNSplitter()]; tX}S[jdq  
nEndPos = new long[bean.getNSplitter()]; %"fKZ  
} ^{bEq\5&  
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} DCUq.q)  
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public void run() ?tQv|x  
{ rL"k-5>fd  
//获得文件长度 =)5a=^ 6  
//分割文件 @23x;x  
//实例FileSplitterFetch =6YO!B>7  
//启动FileSplitterFetch线程 3mz>Y*^?0  
//等待子线程返回 Yk&{VXU<  
try{ HNT8~s.2  
if(bFirst) Y\\nJuJo  
{ RyD$4jk+T"  
nFileLength = getFileSize(); H2cc).8"  
if(nFileLength == -1) Isb^~c_P  
{ 2MeavTr  
System.err.println("File Length is not known!"); gOAluP  
} =(\!,S'  
else if(nFileLength == -2) TvwIro  
{ :!hH`l}p  
System.err.println("File is not access!"); !S{<Xc'wv  
} !WnI`  
else ji=po;g=E  
{ z59J=?|  
for(int i=0;i<nStartPos.length;i++) ~-i
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{ *4y r7~S5  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); tpK4 gjf  
} #ySx
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for(int i=0;i<nEndPos.length-1;i++) Z+7S,M  
{ [.,6~=}vP  
nEndPos = nStartPos[i+1]; ir#^5e@  
} vn0*KIrX  
nEndPos[nEndPos.length-1] = nFileLength; z(eAwmuli  
} e84TLU?~  
} DL_\lu
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czRh.kz,  
//启动子线程 AFED YRX  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; RfRaWbn  
for(int i=0;i<nStartPos.length;i++) &N;6G`3  
{ 4*W7{MPY  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4iW2hV@m  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [_@OCiV5)  
nStartPos,nEndPos,i); *
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); a-y5\x  
fileSplitterFetch.start(); `_i-BdW  
} JY16|ia  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `_`,XkpzCJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ic#drpl,  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", @eWx4bl  
nEndPos = " + nFileLength); i-b7  
// fileSplitterFetch[nPos.length-1].start(); )`-]nMc  
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6B{Awm@v}X  
//等待子线程结束 {{,%p#/b  
//int count = 0; )' #(1 ,1k  
//是否结束while循环 A?zW!
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boolean breakWhile = false; CG;D(AWR;  
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while(!bStop) jU$PO\UTk  
{ a=dN.OB}F7  
write_nPos(); y"ck;OQD  
Utility.sleep(500); i|mA/ e3b  
breakWhile = true; nj$K4_  
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OLwxGRYX  
for(int i=0;i<nStartPos.length;i++) %54![-@  
{ qT4s*kqr  
if(!fileSplitterFetch.bDownOver) 4{KsCd)  
{ ?Dm&A$r  
breakWhile = false; L')zuI  
break; ]u';z
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} ]'q<wPi  
} YBP{4Rl  
if(breakWhile) pxj"<q`nw8  
break; e)kf;Hkf  
/slML~$t<  
9@06]EI_  
//count++; 7Go!W(8  
//if(count>4) =F4}  
// siteStop(); 1F|+4  
} UsTPNQj  
/rW{rf^  
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System.err.println("文件下载结束！"); S SXSgp  
} E_oe1C:  
catch(Exception e){e.printStackTrace ();} U?QO'H5  
} 5hAg*zJb5o  
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)-@EUN0E>5  
//获得文件长度 *)<tyIHd  
public long getFileSize() ]O."M"B  
{ kok
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int nFileLength = -1; Ou^dI  
try{ U VT8TN-T  
URL url = new URL(siteInfoBean.getSSiteURL()); ! bp"pa9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
~CA+'e%~~  
httpConnection.setRequestProperty("User-Agent","NetFox"); gi)/iz`  
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int responseCode=httpConnection.getResponseCode(); KB5{l%>  
if(responseCode>=400) |zMQe}R@%  
{ 8~i@7~ J  
processErrorCode(responseCode); VA0TY/{ ]  
return -2; //-2 represent access is error !Xm:$KH  
} 7}Sw(g)o7  
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String sHeader; "{k3~epYaN  
9M<? *8)  
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for(int i=1;;i++) <Yc:,CU  
{ zP9!fA  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); X$* 'D)  
//Utility.log(in.readLine()); m"*:XfOL  
sHeader=httpConnection.getHeaderFieldKey(i); RY'y%6Z]ZO  
if(sHeader!=null) oZ}e w!V
 
{ g:Dg
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if(sHeader.equals("Content-Length")) X'c5s~9  
{ luMNi^FQ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); CbZ1<r" /  
break; )~`zjVx_  
} jnTl%aQYc  
} NQAnvX;  
else sCUPa-cHF  
break; ^{w&&+#,q  
}
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} p,Z6/e[SI  
catch(IOException e){e.printStackTrace ();} bY>Ug{O;  
catch(Exception e){e.printStackTrace ();} S;])Nt'X'  
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Utility.log(nFileLength); ^!9b#Ja  
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return nFileLength; C$bK!]a  
} (\}IOCNS  
[Ue>KG62=  
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//保存下载信息（文件指针位置） 3 yElN.=  
private void write_nPos() H)S3/%.|  
{ gDsZb
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try{ ^Z*_@A_v  
output = new DataOutputStream(new FileOutputStream(tmpFile)); rnr7t \a~]  
output.writeInt(nStartPos.length); [D t`@Dm  
for(int i=0;i<nStartPos.length;i++) ctZW7  
{ hCmOSDym  
// output.writeLong(nPos); z'fS
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output.writeLong(fileSplitterFetch.nStartPos); d|TIrlA  
output.writeLong(fileSplitterFetch.nEndPos); UW+I 8\^  
} 8X%;29tow  
output.close(); $\bH5|Hk]  
} SBEJ@&iB~  
catch(IOException e){e.printStackTrace ();} BjH(E'K[b  
catch(Exception e){e.printStackTrace ();} en  
} $OT:J  
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//读取保存的下载信息（文件指针位置） ZD,l2DQ?  
private void read_nPos() 8[DD=[&  
{ 4
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try{ Dihk8qJ/6  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); j<!$ug9VA  
int nCount = input.readInt(); 982$d<0%  
nStartPos = new long[nCount]; 4nY2v['m0  
nEndPos = new long[nCount]; GB+G1w  
for(int i=0;i<nStartPos.length;i++) ~ e"^-x  
{ NlKnMgt~  
nStartPos = input.readLong(); T>c;q%A/  
nEndPos = input.readLong(); sLTf).xh  
} DgdW.Kj|IL  
input.close(); Kz%wMyZ:g  
} #zXDh3%]a  
catch(IOException e){e.printStackTrace ();} 1t)6wk N  
catch(Exception e){e.printStackTrace ();} r
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} K|B1jdzL  
+b{\v1b  
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private void processErrorCode(int nErrorCode) BAxZR  
{ VHJr+BQ1K/  
System.err.println("Error Code : " + nErrorCode); }LM_VZj  
} A$5T3j'  
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//停止文件下载 3oSQe"  
public void siteStop() 9orza<#  
{ PC9:nee  
bStop = true;
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for(int i=0;i<nStartPos.length;i++) !XFN/-Q ,  
fileSplitterFetch.splitterStop(); i->sw#  
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} T1x$v,)8x  
} F;zmq%rK  
//负责部分文件的抓取 tHGK<rb  
**FileSplitterFetch.java 7.5G4  
*/ C}!$'C|  
package NetFox; mU3UQ j  
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import java.io.*; rGN-jb)T+  
import java.net.*; nB
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public class FileSplitterFetch extends Thread { S4|)N,#  
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String sURL; //File URL >V]>h&`  
long nStartPos; //File Snippet Start Position nZ{~@E2  
long nEndPos; //File Snippet End Position MM97$  
int nThreadID; //Thread's ID v!x=fjr<  
boolean bDownOver = false; //Downing is over o$Jk27  
boolean bStop = false; //Stop identical /O8'8sL5  
FileAccessI fileAccessI = null; //File Access interface
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6Fm.^9@  
{ Jus)cO#I  
this.sURL = sURL; XL+kEZ|3  
this.nStartPos = nStart; 
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this.nEndPos = nEnd; rp _G.C  
nThreadID = id; X=DJOepH'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *fjarZu  
} xd>2TW l#  
's e9|:  
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public void run() HHX9QebiST  
{ Y&#<{j':  
while(nStartPos < nEndPos && !bStop) "['YMhu_  
{ 1s*I   
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try{ ?"L>jr(  
URL url = new URL(sURL); 9 /9,[A  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Tp9LBF  
httpConnection.setRequestProperty("User-Agent","NetFox"); 
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String sProperty = "bytes="+nStartPos+"-"; VB[R!S
=  
httpConnection.setRequestProperty("RANGE",sProperty); )Dv"seH.  
Utility.log(sProperty); :}E*u^v K  
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InputStream input = httpConnection.getInputStream(); KYlWV<sR  
//logResponseHead(httpConnection); 5uu{f&?u)  
+8~S28"Wg3  
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byte[] b = new byte[1024]; )>=`[$D1t  
int nRead; hwexv 9""  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^tpy8TQ  
{ [7$<sN<'  
nStartPos += fileAccessI.write(b,0,nRead); s cn!,  
//if(nThreadID == 1) ^6Xio6W  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `RjcJ?r  
} H-I*;  
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Utility.log("Thread " + nThreadID + " is over!"); E fqa*,k  
bDownOver = true; c>]_,Br~  
//nPos = fileAccessI.write (b,0,nRead); mNV4"lNR  
} TsR20P@  
catch(Exception e){e.printStackTrace ();} X.JB&~/rO  
} l ='lV]  
} 2!jbaSH(+  
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//打印回应的头信息 _Jx?m  
public void logResponseHead(HttpURLConnection con) .}Xkr+ +]  
{ 8y+Gvk:  
for(int i=1;;i++) 5m_@s?P[  
{ oE5+   
String header=con.getHeaderFieldKey(i); +[*UC"  
if(header!=null) ?p$WqVN}  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); dkCSqNFL)  
Utility.log(header+" : "+con.getHeaderField(header)); 8_KXli}7=  
else ."3
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break; 5|AZ/!rb  
} Ju:=-5r"'  
} LxMOs Nv  
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public void splitterStop() C8(sH@  
{ V @8X.R>  
bStop = true; lMP|$C  
} \f._I+gJ  
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} %S@XY3jZY  
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/* VM-J^  
**FileAccess.java D@\97t+  
*//文件访问(定位，写) o6{XT.z5qx  
package NetFox; c5Offnq'1  
import java.io.*; {\
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@^`
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public class FileAccessI implements Serializable{ /ZD/!YD&R  
M?]ObIM:5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 } 1c5#Ym  
RandomAccessFile oSavedFile; C?b Mj[$  
long nPos; !(+?\+U lE  
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public FileAccessI() throws IOException 1tg   
{ wus]  
this("",0); 3fBq~Q  
} `M\L6o  
yQ&;#`!'  
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public FileAccessI(String sName,long nPos) throws IOException lJq %me;4m  
{ kV-a'"W5  
oSavedFile = new RandomAccessFile(sName,"rw"); R$PiF1ffj  
this.nPos = nPos;  eYS  
oSavedFile.seek(nPos); 1no$|n#  
} nar=\cs~g  
cbS8~Xmj  
}_u)3X.O  
public synchronized int write(byte[] b,int nStart,int nLen) R|tjvp-[}  
{ M"~B_t,Nw  
int n = -1; w/ZV9"BhE  
try{ RCoz;|c`P  
oSavedFile.write(b,nStart,nLen); F[~qgS*;  
n = nLen; #U!J2240  
} ~lQ]PKJ"  
catch(IOException e) [D/q%  
{ 3`-[95w  
e.printStackTrace (); t$s)S>  
} Rk`c'WP0*  
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return n; hj9bMj  
} x
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} :Rq@%rL  
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b/E1v,/<  
/* nEs l  
**SiteInfoBean.java Vd|/]Zj  
*/ -BNW\]}  
package NetFox; ox)/*c<  
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public class SiteInfoBean { RU[{!E  
I7]45pF  
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private String sSiteURL; //Site's URL JCE364$$"  
private String sFilePath; //Saved File's Path ?p\'S w:  
private String sFileName; //Saved File's Name NW^}u~-f  
private int nSplitter; //Count of Splited Downloading File ;Q-sie(#  
d6~wJMFl  
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public SiteInfoBean() 69rVW~Z  
{//nSplitter的缺省值为5 $8X?|fV)  
//default value of nSplitter is 5 :qw:)i  
this("","","",5); \b~zyt6-  
} -!7QH'  
VSM%<-iQ  
|h8C}P&Z  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) m|e!1_:H  
{ 4}96|2L5  
sSiteURL= sURL; x+%lNR  
sFilePath = sPath; ,ad~6.Z_)  
sFileName = sName; 0wxQ,PI1'  
this.nSplitter = nSpiltter; "<bL-k*H)  
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} }|Cw]GW  
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public String getSSiteURL() NOo
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{ TlAY=JwW  
return sSiteURL; H2rh$2  
} "xYMv"X  
{}vW=  
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public void setSSiteURL(String value) +^4"  
{ dqPJ 2j $\  
sSiteURL = value; L"#Tas\5  
} >>K) 4HYID  
^8E/I]-  
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public String getSFilePath() awo=%vJ&  
{ b(K.p?bt  
return sFilePath; u{exQ[,E  
} hnH:G`[F  
/C_O/N  
;LthdY()n(  
public void setSFilePath(String value) &`t-[5O\  
{ "'s`?  
sFilePath = value; Mm|HA
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} rcNM,!dZ  
^!E;+o' t  
:P;#Y7}Y$  
public String getSFileName() 21G]d  
{ W:hR81ci  
return sFileName; '}LH,H:%G  
} (w4#?_  
m[]pIXc(  
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public void setSFileName(String value) cXtL3T+  
{ Q >)?_O(  
sFileName = value; 1*G7Uh@K}  
} T3wR0,  
,tmo6D62  
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public int getNSplitter() Eq'YtqU  
{ Y"G$^3% (]  
return nSplitter; Koahd=  
} Qy$8!(  
>aN@)=h}  
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public void setNSplitter(int nCount) Cg8{NNeD  
{
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nSplitter = nCount; X[grVe  
} T\. 8og  
} E=HS'XKu[K  
}MuXN<DDb  
v#=Wda
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/* tE<L4;t  
**Utility.java R# mZYg  
*/ 0Rrz   
package NetFox; z[] AH#h  
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public class Utility { l&U3jeW-o  
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public Utility() />.&  
{ 7u o4F=%  
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} x8tRa0-q  
)<IbQH|_  
//线程睡眠 =:o)+N
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public static void sleep(int nSecond) uh`~K6&*\w  
{ ;,@3bu>r  
try{ Ba!`x<wa  
Thread.sleep(nSecond); 2ggW4`"c  
} /.7x[Yc  
catch(Exception e) pl|<g9  
{ mS!/>.1[  
e.printStackTrace (); +~8/7V22  
} >Py;6K  
} I`DdhMi7  
+- c#UO
>  
//日志 qt/"$
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public static void log(String sMsg) <$,iYx  
{ 8t9sdqM/C  
System.err.println(sMsg); {RwwSqJ  
}

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public static void log(int sMsg) Ho\K %#u
 
{ e[>(L%QV+  
System.err.println(sMsg); 3)__b:7J  
} QBai;
p{  
} .:l78>f  
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r$G;^  
/* Eu
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**TestMethod.java -}PD0Pzg;=  
*/ [ivJ&'vB  
package NetFox; JFR,QUT  
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|~#!e}L(  
public class TestMethod {
}5zH3MPQH  
cf@:rHB}  
h#;fBQ]   
public TestMethod() \AkeC6[D  
{ ///xx/weblogic60b2_win.exe E2!;W8M  
try{ }^)M)8zS  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); LW ntZ.  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ~cU,3g  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Kgk9p`C(  
fileFetch.start(); 3PI{LU  
} [Gt|Qp[  
catch(Exception e){e.printStackTrace ();} eEezd[p  
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} l&;#`\s!V  
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public static void main(String[] args) 4)Z78H%>  
{ %w'@:~0  
new TestMethod(); S WYiI  
} nVs0
$?}  
} evu@uq  
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