http断点续传简单实现（java)

/* orHVL2 KK  
**SiteFileFetch.java ,vN#U&RS  
*/ `H+Eo<U  
package NetFox; |}mBW@ah  
import java.io.*; i:[B#|%  
import java.net.*; cL1cBWd  
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public class SiteFileFetch extends Thread { t"BpaA^gO  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ~RMOEH.o  
long[] nStartPos; //开始位置 \h0e09& I  
long[] nEndPos; //结束位置 $x2<D :  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 `$#64UZ>U1  
long nFileLength; //文件长度 K1+,y1c  
boolean bFirst = true; //是否第一次取文件 j5/H#_.  
boolean bStop = false; //停止标志 i&bttSRNV  
File tmpFile; //文件下载的临时信息 {_ 1q`5o  
DataOutputStream output; //输出到文件的输出流 hnY^Z_v!  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 4l3N#U0Q  
public SiteFileFetch(SiteInfoBean bean) throws IOException j`tUx# h  
{ @\q~OyV  
siteInfoBean = bean; m3|,c[M1  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6>vj({,1Y*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); tx.YW9xD  
if(tmpFile.exists ()) 5GRN1Aov<  
{ k~hL8ZT[  
bFirst = false; v~xG*e  
read_nPos(); /y-P)3_  
} HR V/ A  
else |LjCtm)@+  
{
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nStartPos = new long[bean.getNSplitter()]; *Js<VR  
nEndPos = new long[bean.getNSplitter()]; -0Q!:5EC  
} +X- k)9  
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} 
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public void run() E7D^6G&i  
{ C1nQZtF R  
//获得文件长度 LTCj
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//分割文件 mR{0*<  
//实例FileSplitterFetch v0y7N_U5n  
//启动FileSplitterFetch线程 nDo|^{!L`  
//等待子线程返回 *X>rvAd3  
try{ _1hqD EM  
if(bFirst) ae<KUThm.  
{ C8jZcs#4  
nFileLength = getFileSize(); Rza\n8  
if(nFileLength == -1) L\B+j+~  
{ yw
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System.err.println("File Length is not known!"); p 2i5/Ly  
} [|>.iH X  
else if(nFileLength == -2) X >**M  
{ IW46-;l7  
System.err.println("File is not access!"); MaEh8
*  
} C&SYmYj^c  
else M-Js"cB[  
{ 8sIGJ|ku
 
for(int i=0;i<nStartPos.length;i++) PM|K*,3J  
{ Ug"B/UUFd  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); l nZ=< T  
} W,<Vr2J[  
for(int i=0;i<nEndPos.length-1;i++) Vr^wesT\Hx  
{ (PNvv/A  
nEndPos = nStartPos[i+1]; 3Q#VD)  
} JrQN-e!  
nEndPos[nEndPos.length-1] = nFileLength; g7H;d  
} ;aF / <r  
} -{w&ya4X  

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//启动子线程 f;b(W  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; mkWIJH  
for(int i=0;i<nStartPos.length;i++) YF"D;.  
{ 87HVD Di  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @#V{@@3$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), s9
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nStartPos,nEndPos,i); wF%XM_M  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $a-~ozr`C  
fileSplitterFetch.start(); 6^zv:C%  
} /Ly%-py-$  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |%tR#!&[:g  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Ve=0_GR0  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $HH(8NoL  
nEndPos = " + nFileLength); E u@TCw8@  
// fileSplitterFetch[nPos.length-1].start(); C*KRu`t  
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eg}|%GG  
//等待子线程结束 jeW0;Cz J~  
//int count = 0; Mpj3<vj   
//是否结束while循环 !qcR5yk`2  
boolean breakWhile = false; h?TE$&CL?  
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while(!bStop) 3v{GP>  
{ jf})"fz-*  
write_nPos(); *</;:?  
Utility.sleep(500);
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breakWhile = true; 9]S}m[8k  
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for(int i=0;i<nStartPos.length;i++)
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{ jeJGxfii  
if(!fileSplitterFetch.bDownOver) =}V`O>  
{ }vm17`Gfy  
breakWhile = false; }R J2\CP  
break; 7f`jl/   
} U%KoG-#  
} !|`YNsR  
if(breakWhile) ;hKn$' '  
break; 5-+Y2tp}  
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//count++; !E*-\}[  
//if(count>4) nGP>M#F  
// siteStop(); ;/YSQt)rc>  
} 9,9( mbWJv  
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System.err.println("文件下载结束！"); -Y+[`0$'  
} K&S~IFy  
catch(Exception e){e.printStackTrace ();} paF2{C)4  
} 
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2 {31"  
//获得文件长度 5:AAqMa  
public long getFileSize() air{1="<-  
{ "PuP J|  
int nFileLength = -1; 3nG(z>  
try{ 'QkL%z0  
URL url = new URL(siteInfoBean.getSSiteURL()); 8Y4YE(x5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); m2 OP=z@)  
httpConnection.setRequestProperty("User-Agent","NetFox"); .&L#%
C  
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int responseCode=httpConnection.getResponseCode(); rb9x||  
if(responseCode>=400) 8^HMK$  
{ 9@^/ON\O  
processErrorCode(responseCode);  ) .#,1
 
return -2; //-2 represent access is error []u!p
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} LtCkDnXk  
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String sHeader; f)*}L?  
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for(int i=1;;i++) f9#B(4Tgi  
{ Yr[1-Oy/k  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); qA*
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//Utility.log(in.readLine()); F-2HE><+  
sHeader=httpConnection.getHeaderFieldKey(i); koaH31Q  
if(sHeader!=null) ncu> @K$n  
{ A87Tyk2Pi  
if(sHeader.equals("Content-Length")) 'e0qdY`  
{ {KODwP'~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); d~YDg{H  
break; *USZ2|i  
} /eZAA
H  
} b7HS3NYk  
else UD"e:O_  
break; #XNe4#  
} 9;q@;)'5  
} p2tBF98  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} y8 `H*s@  
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Utility.log(nFileLength); E]"ePdZZ/  
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return nFileLength; !*EHr09N7  
} 3"&6rdF\jB  
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//保存下载信息（文件指针位置） YAd.i@^  
private void write_nPos() 0Ac]&N d`  
{ ^'[Rb!Q8  
try{ R (4 :_ xc  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Mx[tE?!2  
output.writeInt(nStartPos.length); Kkdd}j
 
for(int i=0;i<nStartPos.length;i++) v;{s@CM m  
{ A*E$_N  
// output.writeLong(nPos); 7&OU!gp  
output.writeLong(fileSplitterFetch.nStartPos); :6Bk<  
output.writeLong(fileSplitterFetch.nEndPos); ^yjc"r%B  
} oP_'0h0X  
output.close(); 0Tg/R4dI  
} Q!|. ,?V  
catch(IOException e){e.printStackTrace ();} naM4X@jl  
catch(Exception e){e.printStackTrace ();} "5ah{,  
} M9 _h0  
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b8Y1.y"#  
//读取保存的下载信息（文件指针位置） 2'_Oi-&  
private void read_nPos() x)nBy)<  
{ pOGVD  
try{ v!K%\h2A  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); e#SNN-hKsJ  
int nCount = input.readInt(); Kl\A&O*{  
nStartPos = new long[nCount]; 6e
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nEndPos = new long[nCount]; %GjF;dJ  
for(int i=0;i<nStartPos.length;i++) h`?0=:Tru  
{ ?cowey\m .  
nStartPos = input.readLong(); rJKX4,M  
nEndPos = input.readLong(); Fl^.J<Dz  
} %\Ig{Rj;  
input.close(); )xlNj$(x5n  
} ,Ix7Yg[  
catch(IOException e){e.printStackTrace ();} <iv9Mg
}  
catch(Exception e){e.printStackTrace ();} noGMfZ1  
} Fu!:8Wp!(  
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private void processErrorCode(int nErrorCode) 3zMmpeq  
{ ,|?B5n&  
System.err.println("Error Code : " + nErrorCode); oI/@w  
} Nbuaw[[iz  
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nS]/=xP{  
//停止文件下载 ^7~=+0cF]  
public void siteStop() -P@o>#Em  
{ 3eFD[c%mN  
bStop = true; Uiv;0Tovl  
for(int i=0;i<nStartPos.length;i++) j#<#o:If  
fileSplitterFetch.splitterStop(); 7Ja^d-F7  
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} =DGaK0n  
} 0'c<EJ  
//负责部分文件的抓取 W~Eq_J?I  
**FileSplitterFetch.java
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*/ _H<ur?G  
package NetFox; {(7C=)8):  
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import java.io.*; e8--qV#<  
import java.net.*; -QI1>7sl  
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public class FileSplitterFetch extends Thread { `b# w3 2  
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String sURL; //File URL {SCwi;m  
long nStartPos; //File Snippet Start Position N}pE{~Y  
long nEndPos; //File Snippet End Position oC^-" (#  
int nThreadID; //Thread's ID BVC\~j j  
boolean bDownOver = false; //Downing is over }V6}>!Sb  
boolean bStop = false; //Stop identical |JnJ=@-y  
FileAccessI fileAccessI = null; //File Access interface 0_,V}  
pU<->d;->  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ;,'eO i  
{ C(xdiQJh  
this.sURL = sURL; Qm^N}>e  
this.nStartPos = nStart; ERCW5b[RT  
this.nEndPos = nEnd; Rb',"` 7  
nThreadID = id;
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 Mpb|qGi!  
} mWfzL'*  
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public void run() s)8g
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{ 2{| U  
while(nStartPos < nEndPos && !bStop) 6]CY[qEaR$  
{ +*lSB%`aS  
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try{ xBl}=M?Qu  
URL url = new URL(sURL); m7~kRY514  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]@C&Q,
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httpConnection.setRequestProperty("User-Agent","NetFox"); v>;6pcp[F  
String sProperty = "bytes="+nStartPos+"-"; Z  r  
httpConnection.setRequestProperty("RANGE",sProperty);
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Utility.log(sProperty); qIuY2b`6  
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InputStream input = httpConnection.getInputStream(); bt-y6,> +E  
//logResponseHead(httpConnection); u4rGe!  
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byte[] b = new byte[1024]; u\Tq5PYXt  
int nRead; D)K/zh)  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) '\[GquK;P  
{ `G@]\)-!  
nStartPos += fileAccessI.write(b,0,nRead); WVir[Kv%  
//if(nThreadID == 1) o~*% g.  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mj{TqF  
}
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Utility.log("Thread " + nThreadID + " is over!"); OU/PB  
bDownOver = true; diaLw  
//nPos = fileAccessI.write (b,0,nRead); :BNqr[=b  
} Y'DI@  
catch(Exception e){e.printStackTrace ();} pbl;n|  
} E&7U |$  
} l]uF!']f  
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//打印回应的头信息 L|u\3.:  
public void logResponseHead(HttpURLConnection con) D0.7an6  
{ ^R! qxSj  
for(int i=1;;i++) K\,)9:`t  
{ dE%rQE7'  
String header=con.getHeaderFieldKey(i); u?&P6|J&  
if(header!=null) S)>L 0^M1  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;
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Utility.log(header+" : "+con.getHeaderField(header)); [K9l>O  
else xKv\z1ra  
break; ,KdDowc  
} ;
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} f)Z$,&  
9
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public void splitterStop() a{GPAzO+  
{ [?Cv^t${+  
bStop = true; N! 
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} C-V,3}=*2  
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} nxS|]  
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/* &'
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**FileAccess.java m6a`OkP  
*//文件访问(定位，写) *GH`u*C_  
package NetFox; Fw)#[  
import java.io.*; 6c$ so  
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public class FileAccessI implements Serializable{ &7VN?ox1  
|A0BYzlVc  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 F>dB@V-  
RandomAccessFile oSavedFile; | (JxtQqQg  
long nPos; =8?y$WE  
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public FileAccessI() throws IOException %@k@tD6  
{ l=GcgxD+"d  
this("",0); HIsIW%B  
} .!e):&(8  
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public FileAccessI(String sName,long nPos) throws IOException w9<<|ZaU  
{ xQ+UZ
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oSavedFile = new RandomAccessFile(sName,"rw"); DvB
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this.nPos = nPos; O2g9<H  
oSavedFile.seek(nPos); ;h<(vc3@f  
} aMe]6cWHV>  
]V0V8fU|  
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public synchronized int write(byte[] b,int nStart,int nLen) dWqKt0uh!  
{ `<2k.aW4e8  
int n = -1; =PYfk6j9  
try{ =.a}  
oSavedFile.write(b,nStart,nLen); RtO3!dGT.  
n = nLen; [ R  
} b 5<&hN4g  
catch(IOException e) /Jj7+?  
{ c!*yxzs\  
e.printStackTrace (); }Z#KPI8\Q  
} 9: N[9;('  
= >CADT
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return n; n_QSuh/Wn  
} )O\w'|$G  
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} IJa6W`}  
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/* Oy EOb>  
**SiteInfoBean.java P1C{G'cR  
*/ /S2lA>  
package NetFox; KCP$i@Pjv  
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public class SiteInfoBean { 0,~||H{  
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private String sSiteURL; //Site's URL Cm@rXA/  
private String sFilePath; //Saved File's Path }?G([s56  
private String sFileName; //Saved File's Name 7>.d*?eao\  
private int nSplitter; //Count of Splited Downloading File 3E9 )~$  
`
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public SiteInfoBean() $ix:S$  
{//nSplitter的缺省值为5
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//default value of nSplitter is 5 bUvVt3cm  
this("","","",5); =jv3O.zq  
} #dA9v7  
!]f80z  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) =z>d GIT1  
{ +FomAs1*f  
sSiteURL= sURL; 43wm_4C!H  
sFilePath = sPath; xmVW6 ,<?  
sFileName = sName; H=lzW_(  
this.nSplitter = nSpiltter; ?vt#M^Q   
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o8_))  
} W(5XcP(  
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public String getSSiteURL() {%wF*?gk  
{ =hRo#]{(K  
return sSiteURL; %_Q+@9  
} CP0;<}k  
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ca=sc[ $+  
public void setSSiteURL(String value) R?{f:,3R  
{ r=6N ZoZ  
sSiteURL = value; elJ?g &"  
} =[JstiT?E  
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public String getSFilePath() t=nZ1GZyM  
{ 8k{Kn
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return sFilePath; Mi~x(W@}3  
} :$6mS[@|  
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public void setSFilePath(String value) -7Bg5{FA  
{ pO?v$Rjl  
sFilePath = value; -kF8ZF  
} h* 72 f/#  
^>Vl@cW0uz  
s(Y2]X4 (  
public String getSFileName() !78P+i  
{ _C@A>]GT  
return sFileName; Ql
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} XX7zm_>+  
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public void setSFileName(String value) YsO3( HS  
{ qnb#~=x^  
sFileName = value; .oS[ DTn5S  
} hbdB67,  
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public int getNSplitter() Tw,|ZA4XH  
{ s"UUo|hM  
return nSplitter; +
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} j/t
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public void setNSplitter(int nCount) 3xk-D &"  
{ Spu> ac  
nSplitter = nCount; s6F0&L;N&  
} M3U?\g  
} `]`S"W7&  
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/* iNs@8<=$T  
**Utility.java VS\| f'E  
*/ ;il+C!6zpf  
package NetFox; A]laS7Q  
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public class Utility { -x{@D{Q%  
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public Utility() `_()|;!y  
{ o)f$ 7.  
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} \kZ@2.pN  
$."DOZQ3U  
//线程睡眠

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public static void sleep(int nSecond) n8E3w:A-  
{ +B[XTn,Cru  
try{ Q#F9&{'l  
Thread.sleep(nSecond); Aj8zFt]  
} }hE!0q~MfM  
catch(Exception e) /PVx  
{ U2)?[C1q{  
e.printStackTrace (); g"~`\xhx  
} EQe$~}[  
} SdF+b+P]  
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//日志 "/G]M&  
public static void log(String sMsg) l)e6*sDZ,  
{ wV\7  
System.err.println(sMsg); Mtl`A'KQ/K  
} AC\y|X8-  
o5['5?i}/  
;eJ|)*  
public static void log(int sMsg) &_q8F,I \<  
{ (}5};v  
System.err.println(sMsg); ^6gEL~m|]  
} t33\f<e  
} n%;4Fm
?  
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`z`=!1  
/* `,O"^zR)z  
**TestMethod.java VnqcpJ  
*/ ?E,-P!&R  
package NetFox; Scug wSB  
3&I3ViAH  
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public class TestMethod { 2Lytk OMf  
SQ*%d.1  
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public TestMethod() xU2i&il^!  
{ ///xx/weblogic60b2_win.exe Jz4;7/  
try{ D9H%jDv  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); S}VN(g  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); fRxn,HyV  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 7|"l/s9,  
fileFetch.start(); Y3#8]Z_"}O  
} W9{i~.zo  
catch(Exception e){e.printStackTrace ();} n!sOKw  
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} aTfc>A;  
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public static void main(String[] args) z0x^HDAeC  
{ ^?_MIS`4N  
new TestMethod(); h@]{j_$u  
} CfO{KiM(2  
} P'SGt  
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