http断点续传简单实现（java)

/* n@bkZ/G  
**SiteFileFetch.java ]!P6Z?  
*/ g9g ]X  
package NetFox; .uX(-8n ~  
import java.io.*; ~v/` `s  
import java.net.*; (kK8 OxfF  
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public class SiteFileFetch extends Thread { j;j~R3B  
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SiteInfoBean siteInfoBean = null; //文件信息Bean $`0^E#Nl  
long[] nStartPos; //开始位置 FChW`b&S  
long[] nEndPos; //结束位置 xk8NX-:  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 G;t<dJ8  
long nFileLength; //文件长度 u|ih
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boolean bFirst = true; //是否第一次取文件 32J/   
boolean bStop = false; //停止标志 Fgwe`[  
File tmpFile; //文件下载的临时信息 9_&]7ABV  
DataOutputStream output; //输出到文件的输出流 $E:z*~?  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） %O(W;O  
public SiteFileFetch(SiteInfoBean bean) throws IOException "AMwo(Yi  
{ bfJ<~ss/  
siteInfoBean = bean; Q(1R=4?.Z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [!KsAsmk  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); *}(
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if(tmpFile.exists ()) r_'];  
{ 1T~`$
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bFirst = false;  d
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read_nPos(); Td^62D;  
} /-@F|,O)$n  
else V~o'L#a  
{ #
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nStartPos = new long[bean.getNSplitter()]; oM#+Z qP  
nEndPos = new long[bean.getNSplitter()]; u,YmCEd_V  
} 8h}1t4k  
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} 6+>X`k%D  
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public void run() 0H
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{ 4.kn,s  
//获得文件长度 MM@&QaK  
//分割文件 rO1N@kd/  
//实例FileSplitterFetch DYZk1  
//启动FileSplitterFetch线程 g
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//等待子线程返回 5X]f}6kT  
try{ rF?QI*`Y(  
if(bFirst) nM8'="$  
{ 6(A"5B=\  
nFileLength = getFileSize(); m5
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if(nFileLength == -1) pwVGe|h%,  
{ 
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System.err.println("File Length is not known!"); .k!2{A  
} G [yI[7=d  
else if(nFileLength == -2) kO
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{ YB{'L +Wbw  
System.err.println("File is not access!"); \Q?#^<O  
} *'n=LB8R  
else {ueDwnZ  
{ rXGaav9  
for(int i=0;i<nStartPos.length;i++) ldaT: er9  
{ v&66F`
  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); cSTL.QF  
} Qq.Ja%Zq  
for(int i=0;i<nEndPos.length-1;i++) 5]3Mj*u\  
{ uD4W@*PYr  
nEndPos = nStartPos[i+1]; eM7F8j  
} >v/%R~BuX  
nEndPos[nEndPos.length-1] = nFileLength; UD2l!)rW  
} _*t75e$-  
} H5gcP11r  

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`Z2-<:]6&a  
//启动子线程 ,;h}<("q  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; E.x<J.[Y  
for(int i=0;i<nStartPos.length;i++) `P;3,@ e  
{ =$kS
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~>%%kQt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), cS#| _  
nStartPos,nEndPos,i); >(Wt  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [/J(E\9  
fileSplitterFetch.start(); 6*tky;  
} 7u%OYt D E  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ZzT"u1,&  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ZZeF1y[q  
nEndPos = " + nFileLength); f_.0 uM  
// fileSplitterFetch[nPos.length-1].start(); #Y'ub 5s  
a7z%)i;Z  
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//等待子线程结束 w(odgD  
//int count = 0; .  
//是否结束while循环 O
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boolean breakWhile = false; 5*y6{7FLp  
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while(!bStop) A(JgAV1{  
{ Qer}eg`R  
write_nPos(); gp^xl>E  
Utility.sleep(500); )Y=ti~?M(  
breakWhile = true; }A<fCm7  
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for(int i=0;i<nStartPos.length;i++) ]rO/I
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{ VQ2
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if(!fileSplitterFetch.bDownOver) o~'UWU'#
 
{ ~2XiKY;W?  
breakWhile = false; h7}P5z0F  
break; X/S%0AwZ  
} mGUG  
} cN:ek|r  
if(breakWhile) !!v9\R4um  
break; Q3LScpp  
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((fFe8Rn)q  
//count++; vPu{xy  
//if(count>4) M9(Kxux#  
// siteStop(); <'P+2(Oi  
} B,{Q[  
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System.err.println("文件下载结束！"); 5e c T.  
} 6"o@d8>v  
catch(Exception e){e.printStackTrace ();} )!l1  
} iuoZk5O  
KyzdJ^xC"  
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//获得文件长度 hh^_Z| 5  
public long getFileSize() l`EKL2n  
{ {MmK:C  
int nFileLength = -1; cq1)b\|  
try{ xcXnd"YYE  
URL url = new URL(siteInfoBean.getSSiteURL()); 9P-I)ZqL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); kO8oH8Vt
 
httpConnection.setRequestProperty("User-Agent","NetFox"); 2D
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int responseCode=httpConnection.getResponseCode(); #Gu(h(Z s  
if(responseCode>=400) vsbD>`I  
{ -+ Mh('K  
processErrorCode(responseCode); ~"U^N:I"  
return -2; //-2 represent access is error (=QiXX1r  
} G-R
E  
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String sHeader; od]1:8OF  
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for(int i=1;;i++) O['5/:-  
{ 'X1/tB8*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); qyY]: (8  
//Utility.log(in.readLine()); Q|W~6  
sHeader=httpConnection.getHeaderFieldKey(i); RjG=RfB'V  
if(sHeader!=null) /8s>JPXKH[  
{ KA]5tVQA  
if(sHeader.equals("Content-Length")) :stA]JB# w  
{
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); x@,B))WlGr  
break; .OvH<%g!.  
} NA
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} -F';1D!l%  
else bB
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break; 2@$`xPg   
} r[kmgPld  
} 3rVWehCv  
catch(IOException e){e.printStackTrace ();} kntn9G  
catch(Exception e){e.printStackTrace ();} _{0
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Utility.log(nFileLength); [!>DQE  
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return nFileLength; OC_i,  
} r>7Dg~)V  
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//保存下载信息（文件指针位置） -jL10~/  
private void write_nPos() PRyzUG&  
{ xSZ+6R|  
try{ +>o} R?xj  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2vX!j!_  
output.writeInt(nStartPos.length); &s_)|K  
for(int i=0;i<nStartPos.length;i++) eR:!1z_h  
{ `>skcvkm  
// output.writeLong(nPos); rsC^Re:*jr  
output.writeLong(fileSplitterFetch.nStartPos); mpDQhD[n  
output.writeLong(fileSplitterFetch.nEndPos); aA&}=lm  
} =F90SyzTy  
output.close(); g,""j`  
} =&v&qne9  
catch(IOException e){e.printStackTrace ();} }#QYZ nR  
catch(Exception e){e.printStackTrace ();} e:zuP.R  
} Q%^!j_#  
.V\:)\<|  
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//读取保存的下载信息（文件指针位置） s_Gf7uC  
private void read_nPos() jL9to6 Hmr  
{ |s*tRag  
try{ ~YCZvJ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); o_&*?k*  
int nCount = input.readInt(); XXZ<r  
nStartPos = new long[nCount]; xC.Tipn>  
nEndPos = new long[nCount]; "*0h=x$  
for(int i=0;i<nStartPos.length;i++) _t;Mi/\P  
{ !d3:`l<  
nStartPos = input.readLong(); p+O,C{^f  
nEndPos = input.readLong(); #tQ__V   
} `{W>Dy  
input.close(); G}p*oz~  
} Q a8;MxK`  
catch(IOException e){e.printStackTrace ();} Dro2R_j{  
catch(Exception e){e.printStackTrace ();} b;Uqyc  
} +C){&/=#  
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private void processErrorCode(int nErrorCode) 
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{ L&h90Az1W  
System.err.println("Error Code : " + nErrorCode); /yO|Q{C}M8  
} \N"=qw^ t  
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//停止文件下载 :x/L.Bz  
public void siteStop() n6s[q-td  
{ =s$UU15  
bStop = true; xO2CgqEb  
for(int i=0;i<nStartPos.length;i++) p}O[A`  
fileSplitterFetch.splitterStop(); kxV
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} R`!'c(V  
} $mq@g  
//负责部分文件的抓取 w@"l0gm+u[  
**FileSplitterFetch.java 5t-dvYgU  
*/ -x0VvkHu  
package NetFox; .0f6b  
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import java.io.*; PcK;L
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import java.net.*; a.!|A(zw  
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public class FileSplitterFetch extends Thread { 2P4$^G[  
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String sURL; //File URL S,%BhQ[  
long nStartPos; //File Snippet Start Position =%+o4\N,  
long nEndPos; //File Snippet End Position etkKVr;Kv  
int nThreadID; //Thread's ID +1Ua`3dWN_  
boolean bDownOver = false; //Downing is over pXv@QD#!  
boolean bStop = false; //Stop identical t (>}  
FileAccessI fileAccessI = null; //File Access interface &S|%>C{P.w  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @#= ail  
{ ^J{tOxO=l  
this.sURL = sURL; 1pT-PO3=  
this.nStartPos = nStart; iF1E 5{dH  
this.nEndPos = nEnd; "<5su5]  
nThreadID = id; 60r4%>d  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 =& .KKr  
} zOzobd  
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p!]$!qHO(  
public void run() u#uT|a.  
{ F1aI4H<(T  
while(nStartPos < nEndPos && !bStop) %qj8*1  
{ ap[{`u  
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try{ DsZBhjCB  
URL url = new URL(sURL); a= *qsgPGL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); e;ej/)no`  
httpConnection.setRequestProperty("User-Agent","NetFox"); ="*:H)
  
String sProperty = "bytes="+nStartPos+"-"; GIGC,zP@k  
httpConnection.setRequestProperty("RANGE",sProperty); JTn\
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Utility.log(sProperty); x."/+/  
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InputStream input = httpConnection.getInputStream(); q V+gQ  
//logResponseHead(httpConnection); c Oi:bC@  
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byte[] b = new byte[1024]; vOl<  
int nRead; ~p0M|  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) i^zncDMA  
{ sa26u`?  
nStartPos += fileAccessI.write(b,0,nRead); 4Y#F"+m.]  
//if(nThreadID == 1) E,nxv+AQ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 50l!f7  
} m5/d=k0l  
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Utility.log("Thread " + nThreadID + " is over!"); bb]r  
bDownOver = true; 6bXR?0$*M.  
//nPos = fileAccessI.write (b,0,nRead); B<p -.tv  
} WzwH;!  
catch(Exception e){e.printStackTrace ();} 2a3RRP  
} WFTXSHcG  
} yaD_c;  
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//打印回应的头信息 XzBnj7E  
public void logResponseHead(HttpURLConnection con) ,4&?`Q  
{ `f~\d.*U  
for(int i=1;;i++) QxaW
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{ g} /efE  
String header=con.getHeaderFieldKey(i); [_pw|BGp  
if(header!=null) MY]<^/Q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 6?C|pO  
Utility.log(header+" : "+con.getHeaderField(header)); ?mCino  
else X?8EPCk  
break; qij<XNZU"&  
} I\DH  
} XFiP8aX<  
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qlJzXq{|`  
public void splitterStop() (WISf}[l;  
{ z9B""ws  
bStop = true; [$<\*d/  
} ..5rW0lr  
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} WX9ABh&5  
g]V_)}
 
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/* @*VfG CQ(  
**FileAccess.java Z@G[\"   
*//文件访问(定位，写) R;]z/|8  
package NetFox; mz'r<v2Tc  
import java.io.*; Q2L>P<87T  
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public class FileAccessI implements Serializable{ Ww[Xqmg  
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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 Q^H8gsv  
RandomAccessFile oSavedFile; (1pR=  
long nPos; m'
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public FileAccessI() throws IOException 2.>WR
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{ '[z529HN  
this("",0); Q/[g
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} R'udC}  
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public FileAccessI(String sName,long nPos) throws IOException fK %${   
{ uSl&d  
oSavedFile = new RandomAccessFile(sName,"rw"); u3B[1Ae:K  
this.nPos = nPos; YXi'^GU@  
oSavedFile.seek(nPos); h|T_ k
 
} %tOGs80_{  
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public synchronized int write(byte[] b,int nStart,int nLen) YcaomPo  
{ e` QniTkT  
int n = -1; @F-InfB8.  
try{ JdK'~-L  
oSavedFile.write(b,nStart,nLen); WEnI[JGe  
n = nLen; {PTB]D'  
} L2,.af6+  
catch(IOException e) /Z?$!u4I  
{ Bo#,)%80  
e.printStackTrace (); zJ=lNb?q  
} NR6wNz&81  
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return n; Tx19\\r  
} n`Y"b&  
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} R[#vFQ  
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/* Xv&&U@7  
**SiteInfoBean.java (^@rr[.o7  
*/ d:X@zUR*)  
package NetFox; X"k:+  
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public class SiteInfoBean { X7g@.Oy`  
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#B!HPlrv  
private String sSiteURL; //Site's URL 'nMj<:0wlD  
private String sFilePath; //Saved File's Path &}y?Lt  
private String sFileName; //Saved File's Name _ g8CvH)?!  
private int nSplitter; //Count of Splited Downloading File E-`3}"{  
p=jpk@RX  
#lY_XV.  
public SiteInfoBean()
VRs|";  
{//nSplitter的缺省值为5 q?
* z<)#  
//default value of nSplitter is 5 1 O?bT,"b  
this("","","",5); QhJuH_f 0  
} B4Fuvi  
J85S'cwZZ  
0Xw$l3@N^  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) */6lyODf  
{ TFAd  
sSiteURL= sURL;
3cA'9  
sFilePath = sPath; * @=ZzL  
sFileName = sName; x##0s5Qn  
this.nSplitter = nSpiltter; Uk'bOp  
1s_N!a  
PU2^4h/[`  
} 0#S#v2r5  
_m.w5n
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public String getSSiteURL() {6tj$&\)  
{ WbWEgd%8.  
return sSiteURL; }WV}in0
 
} t+ vz=`  
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W5Uw=!LdEY  
public void setSSiteURL(String value) xep8CimP'  
{ W;T5[
 
sSiteURL = value; Ntt*}|:QV<  
} w$DHMpW'  
t}YT+S  
&e6!/y&  
public String getSFilePath() ^?8/9o  
{ ;EB^1*AEw  
return sFilePath; X5tx(}j  
} srQGqE~  
%xv*#.<Vj  
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public void setSFilePath(String value) B2,c_[UZ.  
{ q|g>;_  
sFilePath = value; 8CUlE-R5  
} 3oOr*N3R  
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public String getSFileName() 6]sP"  
{ WS ^,@>A  
return sFileName; f.Y [2b  
} TjE'X2/  
}0IeKpu5  
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public void setSFileName(String value) mt]^d;E  
{ |[)n.N65=  
sFileName = value; Y:R*AOx  
} ni85Ne$  
IG Ax+3V  
}a%1$>sj  
public int getNSplitter() GO)5R,  
{  b]gVZ-  
return nSplitter; q5G`q&O5  
} DF>3)oTF  
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public void setNSplitter(int nCount) h343$,))u  
{ 2FcNzAaV  
nSplitter = nCount; brX[-  
} 
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} v5\5:b{/  
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\ZA@r|=$  
/* L54]l^ls>  
**Utility.java 61w ({F  
*/ ob;O,&e0>  
package NetFox; \U3v5|Q  
O6ph_$nt.  
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public class Utility { ?t5<S]'r$  
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public Utility() iB|htH'T  
{ nV`U{}x  
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} N%?R(  
_X|prIOb=  
//线程睡眠 2EOx],(|  
public static void sleep(int nSecond) s"XwO8yhM  
{ fy$?~Ji&  
try{ Eq%f`Qg+1E  
Thread.sleep(nSecond); ^ L]e]<h(  
} /J(vqYK"  
catch(Exception e) wn;)La  
{ 2M*i'K;;)P  
e.printStackTrace (); 58d[>0Xa[g  
} \wDL oR  
} 'b0r?A~c=  
<F8e?xy  
//日志 W*Si"s2  
public static void log(String sMsg) jfi
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{ B 6z 'Q  
System.err.println(sMsg); /Kh,  
} {-lpYD^k3  
kno[!A7_6  
}i{qRx"4  
public static void log(int sMsg) O}w%$ mq  
{ zu.B>INe  
System.err.println(sMsg); Wb>;L@jB7  
} 1_b*j-j  
} :}yT?LIyP  
Af\  
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/* *NG\3%}%|@  
**TestMethod.java b50mMWtG  
*/ xKl1DIN[  
package NetFox; /z_]7]  
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E#\Oe_eq~N  
public class TestMethod { sQJGwZ7  
m8;w7S7,j~  
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public TestMethod() Y!8FW|  
{ ///xx/weblogic60b2_win.exe yIcTc  
try{ B]H8^   
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); @({=~ W^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); op\$(7<d-  
SiteFileFetch fileFetch = new SiteFileFetch(bean);  3%bhW9H%  
fileFetch.start(); ] j8
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} d!UxFY@  
catch(Exception e){e.printStackTrace ();} co~NXpqg  
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B;?)X&n|X  
} /y$Fw9R;  
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public static void main(String[] args) vJaWHC$q  
{ h=
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new TestMethod(); P%)r4+at  
} aG83@ABx  
} "a=Hr4C*r  
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