http断点续传简单实现（java)

/* rel_Z..~  
**SiteFileFetch.java Zo`_vx/{j  
*/ ]sLdz^E3D  
package NetFox; [8jIu&tJf  
import java.io.*; AdD,94/  
import java.net.*; J~}sQ{ 0  
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public class SiteFileFetch extends Thread { !{
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SiteInfoBean siteInfoBean = null; //文件信息Bean \?tE,\Ln  
long[] nStartPos; //开始位置 hg7^#f95u  
long[] nEndPos; //结束位置 Zz/ z7~{  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 WYJH+"@%j  
long nFileLength; //文件长度 xB`j* %  
boolean bFirst = true; //是否第一次取文件 }i$ER,hXh  
boolean bStop = false; //停止标志 iVT)V>Up  
File tmpFile; //文件下载的临时信息 9$f%  
DataOutputStream output; //输出到文件的输出流 oZ5 ,y+L4  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） L;h|Sk]{  
public SiteFileFetch(SiteInfoBean bean) throws IOException e1
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{
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siteInfoBean = bean; swKqsN.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^|%
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); r(j:C%?}C  
if(tmpFile.exists ()) 'C7$,H'  
{ 70-nAv  
bFirst = false; twMDEw#VL  
read_nPos(); u+ b `aB  
} T].Xx`  
else YJGP8  
{ otA'+4\  
nStartPos = new long[bean.getNSplitter()]; G4rd<V0[D  
nEndPos = new long[bean.getNSplitter()]; ^u(-v/D9  
} |BBo  
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} nT :n>ja  
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public void run() T*z*x=<5  
{ ka/>jV"  
//获得文件长度 )LAG$Cn  
//分割文件 qh|fq b  
//实例FileSplitterFetch 6t=)1T  
//启动FileSplitterFetch线程 .WLwAL  
//等待子线程返回 RiG]-K:  
try{ #+&"m7 s  
if(bFirst) tH=jaFJ   
{ ZZ>F ^t  
nFileLength = getFileSize(); %6\L^RP  
if(nFileLength == -1) v,|jmv+:  
{ [}I|tb>Pg  
System.err.println("File Length is not known!"); 9zl-C*9vj  
} MbxJ3"@  
else if(nFileLength == -2) $px1D$F!  
{ _Un*x5u2O  
System.err.println("File is not access!"); ?f= ~Pn+  
} CC)Mws+2  
else VpX*l3  
{ j^.|^q<Y  
for(int i=0;i<nStartPos.length;i++) ''($E/  
{ xwub-yz  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); yMEI^,0"  
} WCY5F  
for(int i=0;i<nEndPos.length-1;i++) T9FGuit9  
{ ,]tEh:QC  
nEndPos = nStartPos[i+1]; ;o158H$gz;  
} [>LO'}%  
nEndPos[nEndPos.length-1] = nFileLength; &r+!rL Kp  
} *4/
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} cx[[K.  
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//启动子线程 5?A<('2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; `(r0+Qx  
for(int i=0;i<nStartPos.length;i++) yU>ucuF  
{ +~EnrrT+W  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;6$W-W _  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9a#Y D;-p  
nStartPos,nEndPos,i); XVF!l>nE  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9"?;H%.  
fileSplitterFetch.start();
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} XMzQ
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), P{HR='2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); JkI|Ojmm/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", @"B{k%+  
nEndPos = " + nFileLength); ~x[(1  
// fileSplitterFetch[nPos.length-1].start(); f\FqZ?w  
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//等待子线程结束 !D!"ftOm  
//int count = 0; {]%7-4E  
//是否结束while循环 -Un"z6*  
boolean breakWhile = false; cSjX/%*!m  
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cd`P'GDF  
while(!bStop) r`$P60,@C  
{ c_t7<  
write_nPos(); Wngc(+6O&  
Utility.sleep(500); _q4Yq'dI  
breakWhile = true; cfPp>EK  
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for(int i=0;i<nStartPos.length;i++) {8 &=t8,c  
{ dkW7k^g  
if(!fileSplitterFetch.bDownOver) pgW^h
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{ (Vn3g ra  
breakWhile = false; |tC=  j.  
break; nt@uVwfQ  
} N;DE,[:<  
} G^Y^)pc]   
if(breakWhile) )LsUO#%DO  
break; %!DTq`F  
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//count++; WpOH1[8v  
//if(count>4) g][n1$%  
// siteStop(); vsPIvW!V  
} 2*V

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!
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System.err.println("文件下载结束！"); qoZe<jW (  
} ;I6C`N  
catch(Exception e){e.printStackTrace ();} #%pY,AK:=  
} y4VO\N!  
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$ nMx#~>a  
//获得文件长度 r?|(
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public long getFileSize() g-H,*^g+  
{ W)^%/lAh  
int nFileLength = -1; l3y}nh+ 8  
try{ P~V ^Efz{  
URL url = new URL(siteInfoBean.getSSiteURL()); [+ : zlA  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >QPCYo<E  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]bbP_n8  
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int responseCode=httpConnection.getResponseCode(); #bCUI*N"P  
if(responseCode>=400) %L$?Mey  
{ 8w#4T:hsuN  
processErrorCode(responseCode); 7#N ?{3i  
return -2; //-2 represent access is error "Xl"H/3r  
} rHqP[[4B'  
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String sHeader; 1r5Z$3t\  
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for(int i=1;;i++) xTqP`ljX  
{ O]?\<&y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); cEn|
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//Utility.log(in.readLine()); #Zi6N  
sHeader=httpConnection.getHeaderFieldKey(i); VCT1GsnE  
if(sHeader!=null) +U>Y.YP  
{ 9{rE7OX*A  
if(sHeader.equals("Content-Length")) Iu(]i?Y  
{ ZXf&pqmG  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); fF2]7:  
break; mRt/d  
} :fUNc^\2  
} jkAru_C  
else 06`caG|]-M  
break; l\!`ZhM,  
} !| q19$  
} roBbo  
catch(IOException e){e.printStackTrace ();} } Fli  
catch(Exception e){e.printStackTrace ();} s#aane  
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Utility.log(nFileLength); yr*~?\  
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return nFileLength; N/1xc1$SB  
} jthyZZ  
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//保存下载信息（文件指针位置） {DE4PE`  
private void write_nPos() X_)I"`  
{ "Y"`'U=v  
try{ 9JeT1\VvHY  
output = new DataOutputStream(new FileOutputStream(tmpFile)); x7i,jMR  
output.writeInt(nStartPos.length); :.f(}sCS  
for(int i=0;i<nStartPos.length;i++) JUJrtKS  
{ di]CYLf  
// output.writeLong(nPos); bxWzm|  
output.writeLong(fileSplitterFetch.nStartPos); +i}uRO  
output.writeLong(fileSplitterFetch.nEndPos); 2Ky|+s[`[  
} bIzBY+P  
output.close(); ? :A%$T  
} 1uEM;O  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} LG{50sP`  
} $O fZp<M  
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//读取保存的下载信息（文件指针位置） %WqUZ+yy  
private void read_nPos() HcV,r,>e  
{ &o&}5Aba9  
try{ .3wx}!:*|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Ci[Ja#p7$h  
int nCount = input.readInt(); )EcfEym.>  
nStartPos = new long[nCount]; -I z,vd  
nEndPos = new long[nCount]; TxKNDu  
for(int i=0;i<nStartPos.length;i++) *ozXilO  
{ ;Y`8Ee4vH  
nStartPos = input.readLong(); !u/c
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nEndPos = input.readLong(); '$4&q629d  
} OLGMy5  
input.close(); [(vV45(E  
} IK8"3+(  
catch(IOException e){e.printStackTrace ();} YpG6p0 nd  
catch(Exception e){e.printStackTrace ();} 67||wh.BU  
} :3b\pEO9\  
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private void processErrorCode(int nErrorCode) 1M?Sl?+j  
{ 76u\#{5  
System.err.println("Error Code : " + nErrorCode); dV^ck+
 
} j*~z.Q|  
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//停止文件下载 [vnxp/v/<  
public void siteStop() |-%dN}O  
{ jS
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bStop = true; ,o0[^-b<  
for(int i=0;i<nStartPos.length;i++) s-F3(mc(  
fileSplitterFetch.splitterStop(); -AQ 7Bd  
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} }_Y\6fcd  
} ' R= OeH  
//负责部分文件的抓取 M{=p0?X  
**FileSplitterFetch.java _+Uf5,.5yU  
*/ {>Qs+]  
package NetFox; Bi0&F1ZC!  
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import java.io.*; 1R]h>'  
import java.net.*; bE jQMlb  
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public class FileSplitterFetch extends Thread { ;9)=~)  
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String sURL; //File URL >^v,,R8j  
long nStartPos; //File Snippet Start Position }To-c'  
long nEndPos; //File Snippet End Position B"t4{1/  
int nThreadID; //Thread's ID z:0
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boolean bDownOver = false; //Downing is over !1<>][F  
boolean bStop = false; //Stop identical JycC\s+%E  
FileAccessI fileAccessI = null; //File Access interface 3)l<'~"z<  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException HzZ
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{ WVx^}_FD0  
this.sURL = sURL; SPINV.  
this.nStartPos = nStart; ~-A"M_n ?  
this.nEndPos = nEnd; =05jjR1  
nThreadID = id; Qqp=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :
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} )r XUJ29.  
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public void run() yq` ,)  
{ `CG% Y>+  
while(nStartPos < nEndPos && !bStop) prGp/"E  
{ q=k[]vD  
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try{ Xs)?PE[   
URL url = new URL(sURL); 9hhYyqGsO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); py\/
m]  
httpConnection.setRequestProperty("User-Agent","NetFox"); I$f'BAw  
String sProperty = "bytes="+nStartPos+"-"; qITd.< k  
httpConnection.setRequestProperty("RANGE",sProperty); "gXvnl  
Utility.log(sProperty); #aadnbf  
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InputStream input = httpConnection.getInputStream(); D ~NWP%H  
//logResponseHead(httpConnection); %vU
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byte[] b = new byte[1024]; okBaQH2lUl  
int nRead; B,A\/%<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) '~pZj"uy  
{ ^!K 8nW{*  
nStartPos += fileAccessI.write(b,0,nRead); (U*Zz+ R   
//if(nThreadID == 1) J*qo3aJjE  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); / KKA/  
} A$]#f  
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Utility.log("Thread " + nThreadID + " is over!"); *35o$P4
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bDownOver = true; wtfM}MW\  
//nPos = fileAccessI.write (b,0,nRead); D!bi>]Yd  
} <-!'V,c  
catch(Exception e){e.printStackTrace ();}
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} h6e,w$IL  
} :a M@"#F  
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//打印回应的头信息 !jN$U%/,%.  
public void logResponseHead(HttpURLConnection con) X+//$J  
{ ^ANz=`N5,  
for(int i=1;;i++) mz^[C7(q'(  
{ Q0TKM>  
String header=con.getHeaderFieldKey(i); 6`)Ss5jzk  
if(header!=null) u6P U(f  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); #s-li b  
Utility.log(header+" : "+con.getHeaderField(header)); ''CowI  
else QtfLJ5vi  
break; PML84*K -  
} ;}AcyVV  
} 2spK#0n.HV  
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public void splitterStop() _B\X&!G.  
{ #M8>
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bStop = true; Jl89}Sf  
} &3Mps[u:h  
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} 76S>xnN  
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/* +Z%8X!Q  
**FileAccess.java tOw[  
*//文件访问(定位，写) b/eo]Id]  
package NetFox; f8L3+u  
import java.io.*; zuBfkW95+  
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public class FileAccessI implements Serializable{ Redxg.P  
+F6R@@rWr  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 A*3R@G*h  
RandomAccessFile oSavedFile; 8hvh xp  
long nPos; X[o"9O|<  
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public FileAccessI() throws IOException 7>|p_o`e  
{ bl;v^HR0)  
this("",0); ZQrgYeQl"  
} O}"fhMk  
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public FileAccessI(String sName,long nPos) throws IOException wGA%h.[M|  
{ n0ls a@l  
oSavedFile = new RandomAccessFile(sName,"rw"); Jf8AKj3  
this.nPos = nPos; .(zZTyZr  
oSavedFile.seek(nPos); $6\W8v  
} 7j%sM&  
9i#K{CkC|  
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public synchronized int write(byte[] b,int nStart,int nLen) G3t 4$3|  
{ z50f$!?  
int n = -1; K?aUIkVs  
try{ -q/FxESp  
oSavedFile.write(b,nStart,nLen); 5V/CYcO  
n = nLen; u+uu?.bM  
} `o!a RX  
catch(IOException e) RlTVx:  
{ G6x
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e.printStackTrace (); MBH/,Yd  
} 4WV)&50  
L\asrdL?=  
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return n; )d-
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} E.~~.2   
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} Sf0[^"7  
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/* Nm/Fc
 
**SiteInfoBean.java ?YbZVoD)J  
*/ *npe]cC  
package NetFox; A?829<  
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public class SiteInfoBean { XS/5y(W  
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private String sSiteURL; //Site's URL OT5'cl  
private String sFilePath; //Saved File's Path BV HO_  
private String sFileName; //Saved File's Name 2nPU $\du  
private int nSplitter; //Count of Splited Downloading File h/%Hk;|9  
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$R<eXDW6:  
public SiteInfoBean() DweWFipyPi  
{//nSplitter的缺省值为5 (&u)FB*  
//default value of nSplitter is 5 m=<;)  
this("","","",5); XL7jUi_4:L  
} n`hes_{,g  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) wfrWpz=FO  
{ ?RD)a`y51  
sSiteURL= sURL; )(pJ~"'L  
sFilePath = sPath; h&6x.ps@  
sFileName = sName; lEC58`Ws  
this.nSplitter = nSpiltter; P&Q 5ZQb  
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} gZs8BKO  
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public String getSSiteURL() f V.(v&  
{ wFaWLC|&  
return sSiteURL; N7xkkAS{  
} JZQ$*K  
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public void setSSiteURL(String value) 8Q1){M9'  
{ :8aIj_qds  
sSiteURL = value; K9*#H(
  
} .W&rcqy  
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public String getSFilePath() -3r&O:  
{ !lF|90=  
return sFilePath; 6X:-Z3  
} 5aTyM_x  
~I>B5^3  
3;`93TO{  
public void setSFilePath(String value) U<NpDjc"  
{ g5to0  
sFilePath = value; \?fl%r2  
} m-a_<xo  
?
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public String getSFileName() s^9N7'  
{ "FaG5X(  
return sFileName; RS/%uxS?  
} Nu{RF  
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public void setSFileName(String value) ^dYLB.'=  
{ MnsnW{VGX  
sFileName = value; fK^FD&sF  
} ki^[~JS>'  
*.EtdcRo[  
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public int getNSplitter() @Cm"lv.hz  
{ h{ce+~X  
return nSplitter; H$ xSl1>E  
} tO?*x/XC{  
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public void setNSplitter(int nCount) )11/B
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{ BoIe<{X(9  
nSplitter = nCount; NnSI=M  
} uW[s?  
} {M E|7TS=  
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/* Z/uRz]Hi  
**Utility.java S,S_BB<Y[b  
*/ 7!JoP?!  
package NetFox; 6aQ{EO-]'=  
jO:<"l^+u  
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public class Utility { qm]ljut  
JEBo!9  
"Jnq~7]  
public Utility() B?Y%y@.  
{ p|Rxy"}  
hY'"^?OP  
dt3Vy*zL  
} ~`_nw5y  
.#WF'  
//线程睡眠 '}4[m>/  
public static void sleep(int nSecond) ^Z:x poz,  
{ NnHM$hEI"U  
try{ F<-Pbtw  
Thread.sleep(nSecond); ~P6K)V|@<  
} L1C'V/g  
catch(Exception e) [TO:-8$.  
{ 3y 3 U`Mo  
e.printStackTrace (); 3+ i(fg_  
} nNilTJ   
} (%+DE4?  
^QW%<X  
//日志 R!pV`N  
public static void log(String sMsg) &<^@/osi  
{ !>S'eXt  
System.err.println(sMsg); `&9#!T.  
} <"[}8  
Dh +^;dQ6  
PL+fLCk,I  
public static void log(int sMsg) ={L:q8v)  
{ [>_(q|A6+  
System.err.println(sMsg); B~PF<8h5  
} "F[VqqD  
} =C3l:pGMB;  
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/* [[s k  
**TestMethod.java Y?%6af+  
*/ @MB;Ez v  
package NetFox; >9u6@  
!^"hYp`  
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public class TestMethod { ~C!vfPC  
MzG(+B  
:Dr& {3>  
public TestMethod() HZK0Ldf  
{ ///xx/weblogic60b2_win.exe ]-PF?8  
try{ ?4lAL  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); caj)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); s` 9zW,  
SiteFileFetch fileFetch = new SiteFileFetch(bean); x(=kh%\;  
fileFetch.start(); o$-8V:)6d  
} v\MH;DW^Z  
catch(Exception e){e.printStackTrace ();} )E[5lD61  
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} dl":?D4H  
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public static void main(String[] args) vy"Lsr3  
{ ;!~;05^iD  
new TestMethod(); dIpt&nH&$  
} 'Vrev8D  
} rf`Br\g8  
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