http断点续传简单实现（java)

/* ?\_vqW  
**SiteFileFetch.java (g0U v.*  
*/ 
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package NetFox; bJ^Jmb  
import java.io.*; lu;gmWz  
import java.net.*; *3rp g  
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public class SiteFileFetch extends Thread { )WsR 8tk  
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SiteInfoBean siteInfoBean = null; //文件信息Bean rm4t  
long[] nStartPos; //开始位置 V(;c#%I2  
long[] nEndPos; //结束位置 DWupLJpk;c  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +do*C=z  
long nFileLength; //文件长度 RmJ|g<  
boolean bFirst = true; //是否第一次取文件 J~)JsAXAI  
boolean bStop = false; //停止标志 uvJmEBL:  
File tmpFile; //文件下载的临时信息 `$XgfMBf |  
DataOutputStream output; //输出到文件的输出流 #6mr'e1  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 6\USeZh  
public SiteFileFetch(SiteInfoBean bean) throws IOException <jqL4!<  
{ @./@"mR<  
siteInfoBean = bean; *0Wkz
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); J3hhh(  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); V$bq|r  
if(tmpFile.exists ()) u3\_![Jt?  
{ ?f:ND1jU  
bFirst = false; CEJqo8ds  
read_nPos(); >=/DCQ$  
} 0Ok[`r`  
else 2
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{ 'j;i4ie>*x  
nStartPos = new long[bean.getNSplitter()]; SK5__Ix  
nEndPos = new long[bean.getNSplitter()]; y\R-=Am".  
} :PNhX2F  
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} &?# YjU"  
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public void run() \`W8#fob  
{ j43i:c;F  
//获得文件长度 s8SCEpz  
//分割文件 Iv/h1j> H  
//实例FileSplitterFetch 83F]d+n  
//启动FileSplitterFetch线程 u.2^t:A  
//等待子线程返回 h<i.Z7F;tj  
try{ 2=$ F*B>9  
if(bFirst)
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{ (zw.?ADPCT  
nFileLength = getFileSize(); .}Hs'co  
if(nFileLength == -1) \zzPsnFIg  
{ c 6/lfgN  
System.err.println("File Length is not known!"); q#`;G,rs  
} S+l>@wa)|  
else if(nFileLength == -2) 6C!TXV'  
{ jF-0fK;)*  
System.err.println("File is not access!"); c3*9{Il^  
} +/rh8?  
else 3iw.yR  
{ g_)i)V  
for(int i=0;i<nStartPos.length;i++) F6"QsFG  
{ =z'533C  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9#a/at]  
} $x2G/
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for(int i=0;i<nEndPos.length-1;i++) mxICQ>s b  
{ 1-PFM-  
nEndPos = nStartPos[i+1]; W=4|ahk$  
} k[\JT[M
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nEndPos[nEndPos.length-1] = nFileLength; .jl^"{@6  
} !
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} H%;pPkIi  
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//启动子线程 @'"7[k!y;  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 5#::42oE  
for(int i=0;i<nStartPos.length;i++) iOiXo6YE  
{ Hn
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z|j\_VKhl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), p7[&H/  
nStartPos,nEndPos,i); a KIS%M#Y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4|NcWpaV7  
fileSplitterFetch.start(); l#a*w  
} Pz-=Eq  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #!4`t]E<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Mm%b8#Fe!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", xI8v'[3  
nEndPos = " + nFileLength); e*o:ltP./  
// fileSplitterFetch[nPos.length-1].start(); P7!gUxcv9Y  
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//等待子线程结束 r6L  
//int count = 0; !%QbE[Kl>  
//是否结束while循环 t}gK)"g  
boolean breakWhile = false; u HXb=U  
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while(!bStop) q[+V6n`Z5  
{ W |+&K0M  
write_nPos(); SpZmwa #\  
Utility.sleep(500); [Rzn>  
breakWhile = true; [}y"rs`!  
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for(int i=0;i<nStartPos.length;i++) \?AA:U*  
{ kaVYe)~  
if(!fileSplitterFetch.bDownOver) HK<oNr.d52  
{ hYh~[Kr^@^  
breakWhile = false; 6H:EBj54?  
break; {=_xze)  
} Y4*?QBYA  
} 2hTH  
if(breakWhile) I#|ib  
break; OgkbN`  
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//count++; i(kr#XsU  
//if(count>4) 42 Sk`  
// siteStop(); 4'XCO+i#  
} &XSe&1  
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System.err.println("文件下载结束！"); _x?S0R1  
} m\ /V0V\  
catch(Exception e){e.printStackTrace ();} \>4x7mF!  
} WI54xu1M  
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6 i]B8Ziq{  
//获得文件长度 #^q@ra  
public long getFileSize() b!g8NG  
{ I)4NCjcCw  
int nFileLength = -1; V_pKe~  
try{ 5@~5RNrq2  
URL url = new URL(siteInfoBean.getSSiteURL()); LU@+O12  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n:YA4t7S  
httpConnection.setRequestProperty("User-Agent","NetFox"); DJHE6XJ   
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int responseCode=httpConnection.getResponseCode(); sB`zk[R;  
if(responseCode>=400) SZD@<3Nb  
{ YR$d\,#R  
processErrorCode(responseCode); ">S.~'ds  
return -2; //-2 represent access is error +6x:+9S  
} E)F"!56lV  
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String sHeader; ~kPZh1n`  
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for(int i=1;;i++) 3/2G~$C  
{ r$-]NYPi  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); vm"dE4W=  
//Utility.log(in.readLine()); :@+@vM;gh  
sHeader=httpConnection.getHeaderFieldKey(i); gnU##Km|  
if(sHeader!=null) +4k7ti1Qb  
{ q=cH ^`<.  
if(sHeader.equals("Content-Length")) G-sA)WOF  
{ y&+Sp/6BYA  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 44cy_  
break; TzK[:o  
} NeY,Of|  
} 8BwJWxBQ  
else ;923^*\:F{  
break; >zB0+l  
} I?i,21:5  
} JV9Ft,xk  
catch(IOException e){e.printStackTrace ();} X.!|#FWb+  
catch(Exception e){e.printStackTrace ();} e5fzV.'5  
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Utility.log(nFileLength); }K\m.+%=d  
< 5#}EiT5  
{ Sn J  
return nFileLength; SiSxym  
} -pm^k-%v  
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//保存下载信息（文件指针位置） 5R7DD5c[  
private void write_nPos() _ ?Z :m  
{ !RwOUCk  
try{ o9uir"=  
output = new DataOutputStream(new FileOutputStream(tmpFile));  (.B+U'6  
output.writeInt(nStartPos.length); Ndr4e?Xa,  
for(int i=0;i<nStartPos.length;i++) .\+%Q)?h:  
{ ;]Bkw6o  
// output.writeLong(nPos); Kzgnhgc  
output.writeLong(fileSplitterFetch.nStartPos); Smlf9h&  
output.writeLong(fileSplitterFetch.nEndPos); }
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} *^P$^lm?S  
output.close(); t.WWahNyY  
} t@\op}Z-M  
catch(IOException e){e.printStackTrace ();} Vy[ m%sEP  
catch(Exception e){e.printStackTrace ();} z gDc=  
} seo.1.Da2  
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//读取保存的下载信息（文件指针位置） )X-/0G=N-  
private void read_nPos()
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{ " tUF,G(<  
try{ IF$*6 ,v.z  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <:UP  
int nCount = input.readInt(); <v=T31aS  
nStartPos = new long[nCount]; X6Hd%}*mN  
nEndPos = new long[nCount]; !c8hER!  
for(int i=0;i<nStartPos.length;i++) /NFcIU  
{ l TRQ/B  
nStartPos = input.readLong(); Zm!5X9^!  
nEndPos = input.readLong(); csay\Q{  
} k3B-;%3I;  
input.close(); 1W +QcK4k  
} D/-$~u_o  
catch(IOException e){e.printStackTrace ();} L H`z '7&/  
catch(Exception e){e.printStackTrace ();} KnuQ
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} R3=]Av46  
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private void processErrorCode(int nErrorCode) 0*Is#73rjY  
{ jVtRn.qh  
System.err.println("Error Code : " + nErrorCode); m'i^BE  
} R59'
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#ig* !  
//停止文件下载 <^(g<B`>  
public void siteStop() &.}Zj*BD  
{ CsND:m  
bStop = true; Tp?l;DU  
for(int i=0;i<nStartPos.length;i++) EFb"{L  
fileSplitterFetch.splitterStop(); I6E!$}  
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} NXw$PM|+R  
} g$jZpU  
//负责部分文件的抓取 E}WO?xxv74  
**FileSplitterFetch.java $m-rn'Q  
*/ CAl]Kpc  
package NetFox; n@Ar%%\  
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import java.io.*; ,[{)4J$MV  
import java.net.*; u`2[V4=
L  
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public class FileSplitterFetch extends Thread { "2'pS<|  
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String sURL; //File URL oG_-a(N  
long nStartPos; //File Snippet Start Position xiW;Y{kZ  
long nEndPos; //File Snippet End Position s;;"^5B.  
int nThreadID; //Thread's ID E{Ux|r~  
boolean bDownOver = false; //Downing is over JBKCa 3  
boolean bStop = false; //Stop identical ZRd,V~iz  
FileAccessI fileAccessI = null; //File Access interface V@"Y"}4n4  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException oHbG-p  
{ QP{V  
this.sURL = sURL; +$F_7Hx  
this.nStartPos = nStart; ny]R,D0  
this.nEndPos = nEnd; n(MVm-H  
nThreadID = id; /.u0rxoRP}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "/zI
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} =#"ZO  

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public void run() ?
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{ RN%*3{-  
while(nStartPos < nEndPos && !bStop) ,'m<YTF  
{ O*ql!9}E{  
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try{ oe
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URL url = new URL(sURL); L/VlmN_v>s  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $C;)Tlh  
httpConnection.setRequestProperty("User-Agent","NetFox"); dSkW[r9Z%l  
String sProperty = "bytes="+nStartPos+"-"; E?z~)0z2`  
httpConnection.setRequestProperty("RANGE",sProperty); ^atX/  
Utility.log(sProperty); h8Bs=T  
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InputStream input = httpConnection.getInputStream(); $bd&$@sA  
//logResponseHead(httpConnection); azxGUS_i<  
#Wz7ju;  
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byte[] b = new byte[1024]; &ZRriqsQg  
int nRead; EC4RA'Bg1k  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .qcIl)3  
{ POtj6 ?a  
nStartPos += fileAccessI.write(b,0,nRead); Q3$AL@".  
//if(nThreadID == 1) ;ss,x  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); cBO.96ZHE  
} &pCNOHi|  
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Utility.log("Thread " + nThreadID + " is over!"); 
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bDownOver = true; P)2.Gx/  
//nPos = fileAccessI.write (b,0,nRead); NRM=0-16u$  
} VoOh$&"M  
catch(Exception e){e.printStackTrace ();} \!erP!$x.  
} .FarKW  
} |Mj2lZS  
IwfJDJJ  
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//打印回应的头信息 ya<nD'%9  
public void logResponseHead(HttpURLConnection con) \Tc<27-  
{ i58&o@.H<u  
for(int i=1;;i++) |
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{ _%xe:X+ M  
String header=con.getHeaderFieldKey(i); c==5cMUg  
if(header!=null) :/c40:[  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ,[ UqUEO  
Utility.log(header+" : "+con.getHeaderField(header)); OM]d}}=Y  
else yZ_6yJw3}  
break; %[<@$qP  
} |#_F  
} ']N1OVw^vf  
-A?6)ggf.  
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public void splitterStop() 56;^ NE4  
{ :6 , `M,  
bStop = true; Z?Cl5o&lb  
} 1%v!8$  
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} KlMSkdmW  
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/* 4@iMGYR9!s  
**FileAccess.java [9wuaw"~[Z  
*//文件访问(定位，写) $ ]ew<j  
package NetFox; y@#JzfY?Hr  
import java.io.*; %j.B/U$  
@>r3=s.Q  
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public class FileAccessI implements Serializable{ !O`a
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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 <|!?V"`3  
RandomAccessFile oSavedFile; pk%%}tP<  
long nPos; [t
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public FileAccessI() throws IOException K1th>!JW'  
{ FZvh]ZX  
this("",0); :7WeR0*%  
} BHNcE*U}@?  
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public FileAccessI(String sName,long nPos) throws IOException ,2|(UTv  
{ Oc Gg'R7  
oSavedFile = new RandomAccessFile(sName,"rw");
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this.nPos = nPos; ~t>i+{JKE  
oSavedFile.seek(nPos); s=Cu-.~L  
} oMb&a0-7u  
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public synchronized int write(byte[] b,int nStart,int nLen) _Q**4  
{ q =\3jd  
int n = -1; }nsxo5WP  
try{ dR9[K4`p/  
oSavedFile.write(b,nStart,nLen); m]7oT
mS  
n = nLen; n$*e(  
} L
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catch(IOException e) #OQT@uF!
 
{ fEWXC|"  
e.printStackTrace (); j3Sz+kOf,  
} 0SHF 8kek  
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return n;  dcd9AW=  
} +Fk]hCL  
{o."T/?d'  
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} I+!?~]AUuq  
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/* pzQWr*5a  
**SiteInfoBean.java kKFhbHUZa  
*/ (}4]U=/nV  
package NetFox; r(VGdG  
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public class SiteInfoBean { Ag82tDL[u  
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private String sSiteURL; //Site's URL 4Odf6v,*@  
private String sFilePath; //Saved File's Path %>mB"Y,  
private String sFileName; //Saved File's Name MYlPG1X=?  
private int nSplitter; //Count of Splited Downloading File ta*6xpz-\Q  
3d>3f3D8;  
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public SiteInfoBean() <hv {,1p-r  
{//nSplitter的缺省值为5 aANzL  
//default value of nSplitter is 5 !&f>,?wlP  
this("","","",5); ~Pm[Ud  
} C-TATH%f^  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) a3Fe42G2c|  
{ '",+2=JJ  
sSiteURL= sURL; }#Q?\  
sFilePath = sPath; 6p}dl>T_y  
sFileName = sName;  {ch+G~oS  
this.nSplitter = nSpiltter; z~f;5xtI  
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} %n!7'XF'[  
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public String getSSiteURL() k0e {c  
{ m35$4  
return sSiteURL; M
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} N+#lS7  
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public void setSSiteURL(String value) ]tnf<5x  
{ +p\+15  
sSiteURL = value; #$?!P1  
} vyXL F'L  
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public String getSFilePath() O~bJ<O=?  
{ 6$ \69   
return sFilePath; ^*@D%U  
} 4*Y`Pn@  
0%b!ARix  
[Q:C\f]  
public void setSFilePath(String value) jFwu&e[9;  
{ Frd`u.I  
sFilePath = value; [izP1A$r#Q  
}
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public String getSFileName() v*3tqT(%  
{ `}
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return sFileName; 8n~
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} G{!adBna  
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public void setSFileName(String value) 11Y4oS  
{ s<b(@L 1  
sFileName = value; 9_&N0>OF  
} U3rpmml  
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public int getNSplitter() zYZ^/7)  
{ ^3 6oqe{  
return nSplitter; hI}rW^o^  
} Q!`  
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public void setNSplitter(int nCount) yE=tuHv(0  
{ !IAd.<,  
nSplitter = nCount; yGZsPQIaV  
} /~6)Vt  
} =t!$72g\  
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/* "}ZUa~7  
**Utility.java i0py5Q  
*/ :kw14?]_  
package NetFox; 9|5>?'CqP  
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public class Utility { J,,+JoD  
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public Utility() 5 cz6\A&  
{ 97-=Vb  
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} Q2jl61d_9  
?<h|Q~JH  
//线程睡眠 c3X8Wi7m  
public static void sleep(int nSecond) K
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{ .~jn N  
try{ S<=
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Thread.sleep(nSecond); rG"QK!R5  
} iD`>Bt7gD  
catch(Exception e) ,.-85isco  
{ ^h~oxZJw  
e.printStackTrace (); r3mQoTvnv  
} vI1UFD D  
} 5nh:S0M6V  
-gR }^D  
//日志 e,I{+^P  
public static void log(String sMsg) >X0c:pPu  
{ T*v@hbJ  
System.err.println(sMsg); b_%W*Q  
} C=!YcJ9  
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public static void log(int sMsg) A;e0h)F$-  
{ <rAWu\d;  
System.err.println(sMsg); 6"PwOEt  
} n^:Wc[[m  
} ~h@<14c{X  
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/* ` 8OA:4).  
**TestMethod.java >^(Q4eU7!  
*/ 3E`poE  
package NetFox; |C_sP,W  
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VSQxlAGk@  
public class TestMethod { /'WVRa  
&XH{,fv$  
S)~Riuy$  
public TestMethod() l!9G  
{ ///xx/weblogic60b2_win.exe ]xf|xs  
try{ ,.PW qfb  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .BqSE  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); BBUXoz  
SiteFileFetch fileFetch = new SiteFileFetch(bean); w7Y>B`wm?  
fileFetch.start(); 97~*Z|#<+  
} .>bvI1  
catch(Exception e){e.printStackTrace ();} s\#eD0|  
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} Lf}@v  
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public static void main(String[] args) `Q~`Eq?@  
{ y*fU_Il|!  
new TestMethod(); `Z!NOC  
} J^]Y`Q`  
} $IB>a  
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