http断点续传简单实现（java)

/* onmpMU7w  
**SiteFileFetch.java _<]0hC  
*/ +@uA  
package NetFox; j|8!gW  
import java.io.*; y=sae  
import java.net.*; Lios1|5  
..Dm@m}  
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public class SiteFileFetch extends Thread { ;07$G+['  
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_1RvK? ;.{  
SiteInfoBean siteInfoBean = null; //文件信息Bean =p5]r:9W  
long[] nStartPos; //开始位置 O`Qke
Z}  
long[] nEndPos; //结束位置 iOIq2&sV  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 MB:[: nX  
long nFileLength; //文件长度 VMF?qT3Nd  
boolean bFirst = true; //是否第一次取文件 FO>!T@0G  
boolean bStop = false; //停止标志 ">!pos`<C  
File tmpFile; //文件下载的临时信息 R`$Y]@i&B  
DataOutputStream output; //输出到文件的输出流 ;o)'dK  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） tq,^!RSbZ  
public SiteFileFetch(SiteInfoBean bean) throws IOException [>>_%T\I  
{ oQpGa>6U&  
siteInfoBean = bean; )?OdD7gd  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Kg~D~ +j  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); QuMv1)n  
if(tmpFile.exists ()) G>:v1lde  
{ uX!6:v]  
bFirst = false; iVnMn1h  
read_nPos(); {/)i}V#RE  
} vN v'%;L  
else H!0m8LCnb  
{ 0827z  
nStartPos = new long[bean.getNSplitter()]; T~$Eh6 D  
nEndPos = new long[bean.getNSplitter()]; [;aM8N  
} ~tTn7[!  
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} |5`e
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public void run() JFc,f  
{ A@_>9;   
//获得文件长度 .3UJ*^(?  
//分割文件 <sm"3qs"_  
//实例FileSplitterFetch '_7rooU9  
//启动FileSplitterFetch线程
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//等待子线程返回 _#v"sGmN  
try{ {[:C_Up)f  
if(bFirst) N LQ".mM+  
{ 9[X'9*,  
nFileLength = getFileSize(); Fh
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if(nFileLength == -1) y@$E5sz  
{ ha;fxM]  
System.err.println("File Length is not known!"); +1yi{!j1  
} LKI\(%ba#  
else if(nFileLength == -2) ,<K+.7,)E  
{ ^Os }sJ*5S  
System.err.println("File is not access!"); Qp[
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} p),*4@2<  
else &qPezyt  
{ A0@,^|]  
for(int i=0;i<nStartPos.length;i++) N2 3:+u<)E  
{ A{-S )Z3}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); fnr8{sr.2Z  
} Q[#8ErUY  
for(int i=0;i<nEndPos.length-1;i++) 3f^jy(  
{ c\>I0HH;!  
nEndPos = nStartPos[i+1]; Z2g<"M  
} {Mb<onW  
nEndPos[nEndPos.length-1] = nFileLength; ng|
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} &R.5t/x_  
} ORP<?SG55u  
G na%|tUz|  
tboQn~&4  
//启动子线程 '{~[e**  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];  WvF{`N  
for(int i=0;i<nStartPos.length;i++) Q\IViM  
{ ;*zLf 9i  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Hc<@T_h+2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Q3=5q w^  
nStartPos,nEndPos,i); y2?9pVLa\y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); PHT<]:"`<  
fileSplitterFetch.start(); 'l!\2Wv2  
} l,Y5VGiH#  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Wk3-J&QbS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); *szs"mQ/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", SX'NFdY  
nEndPos = " + nFileLength); Ebj0 {ZL  
// fileSplitterFetch[nPos.length-1].start(); 1 Vc_jYO@  
j3%Wrt  

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//等待子线程结束 3t.!5L  
//int count = 0; 05HCr"k  
//是否结束while循环 YR~e_cA:  
boolean breakWhile = false; xjnAK!sD  
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while(!bStop) b@4UR<  
{ /@ g 8MUq7  
write_nPos(); d)biMI}<5  
Utility.sleep(500); r|ZB3L|7  
breakWhile = true; :epB:r  
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for(int i=0;i<nStartPos.length;i++) A0A|cJP
 
{ Bx}"X?%S  
if(!fileSplitterFetch.bDownOver) oF+yh!~mM  
{ G6>sAOf  
breakWhile = false; K\B!tk  
break; dn])6Xl;i  
} Hr}"g@ <  
} <W3p!  
if(breakWhile) "38<14V
 
break; 6ZI7V!k  
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//count++; ^)Y3V-@t  
//if(count>4) &Q"vXs6Gt  
// siteStop(); N GnE  
} bvZD@F`2  
3;}YW^oXq  
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System.err.println("文件下载结束！"); yr>J^Et%_  
} G.XxlI}  
catch(Exception e){e.printStackTrace ();} k 75 p  
}
6 mLC{X[  
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//获得文件长度 1#"wfiW  
public long getFileSize() B[8RBTsA  
{ 7yg{0a  
int nFileLength = -1; &``nD  
try{ GFbn>dY  
URL url = new URL(siteInfoBean.getSSiteURL()); G] tT=X[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b9i_\  
httpConnection.setRequestProperty("User-Agent","NetFox"); jM6$R1HX  
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int responseCode=httpConnection.getResponseCode(); Z \ @9*  
if(responseCode>=400) zSsBbu:  
{ s/~[/2[bnf  
processErrorCode(responseCode); ? B|i  
return -2; //-2 represent access is error im:[ViR {  
} t W   
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tQ'R(H`  
String sHeader; @pv:uON\  
Qz{Vl>"  
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for(int i=1;;i++) .uX(-8n ~  
{ :u=y7[I  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Z(4/;v <CT  
//Utility.log(in.readLine()); j&A9 &+w  
sHeader=httpConnection.getHeaderFieldKey(i); u}R|q  
if(sHeader!=null) MxGQM>  
{ PPpaH!(D  
if(sHeader.equals("Content-Length")) v\!Cq+lFML  
{ d1^5r 31  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); c??m9=OX1  
break; fIx|0,D&7L  
} H)*%eG~  
} ^Vh^Z)gGi  
else +dq2}gM  
break; Y@ ;/Sf$Q  
} qB
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} Te)%L*X  
catch(IOException e){e.printStackTrace ();} BgCEv"G5  
catch(Exception e){e.printStackTrace ();} ,T 3M  
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Utility.log(nFileLength); sKiy
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return nFileLength; w[QC  
} \:n<&<aVSr  
<Z~Nz>'r  
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//保存下载信息（文件指针位置） ~U8#yo  
private void write_nPos() @frV:%  
{ Pa|*Jcr  
try{ MM@&QaK  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5V0#_!QAN  
output.writeInt(nStartPos.length); JGzEm>_m  
for(int i=0;i<nStartPos.length;i++) rF?QI*`Y(  
{ mv*M2NuhT  
// output.writeLong(nPos); &;vMJ   
output.writeLong(fileSplitterFetch.nStartPos); Je'%E
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output.writeLong(fileSplitterFetch.nEndPos); G
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} +H? XqSC  
output.close(); ~me/ve  
} PEKXPFN  
catch(IOException e){e.printStackTrace ();} BH$hd|KD<  
catch(Exception e){e.printStackTrace ();} URr{J}5  
} 2'ws@U}lR  
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g
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//读取保存的下载信息（文件指针位置） 7.yCs[Z  
private void read_nPos() >v/%R~BuX  
{ UD2l!)rW  
try{ \/m-G:|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3?&P^{  
int nCount = input.readInt(); ub4(g~E  
nStartPos = new long[nCount]; AY9#{c>X  
nEndPos = new long[nCount]; )o::~ eu  
for(int i=0;i<nStartPos.length;i++) fzjtaH?  
{ ?IiFFfs  
nStartPos = input.readLong(); ZzT"u1,&  
nEndPos = input.readLong(); 1HRcEzA  
} j  W-K  
input.close(); clT[?
8*  
} 'L%)B-,n  
catch(IOException e){e.printStackTrace ();} [hiV#  
catch(Exception e){e.printStackTrace ();} - l0X]&Ex  
} <Um5w1  
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private void processErrorCode(int nErrorCode) RE;)#t?K  
{ G|UeR=/  
System.err.println("Error Code : " + nErrorCode); m]VOw)mBF  
}
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*W4~.peoE  
V67<Ky>  
//停止文件下载 pvM`j86 _  
public void siteStop() +'9xTd  
{ xI5zP? _v  
bStop = true; V:8{MO(C\  
for(int i=0;i<nStartPos.length;i++) C^ ~[b o  
fileSplitterFetch.splitterStop(); `6*1mE1K&  
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R+=Xr<`%U|  
} l27J  
} %/K;!'7  
//负责部分文件的抓取 Mbxrj~ue  
**FileSplitterFetch.java }pT>dbZ
  
*/ @.v{hkM`  
package NetFox; ].N%A07  
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import java.io.*; -$f$z(h  
import java.net.*; G>+iisb%  
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public class FileSplitterFetch extends Thread { wgKM6?  
,k6V?{ZA  
#Gu(h(Z s  
String sURL; //File URL vsbD>`I  
long nStartPos; //File Snippet Start Position -+ Mh('K  
long nEndPos; //File Snippet End Position ~"U^N:I"  
int nThreadID; //Thread's ID 'n"n;  
boolean bDownOver = false; //Downing is over o:RO(oA0?  
boolean bStop = false; //Stop identical ]Cc8[ZC  
FileAccessI fileAccessI = null; //File Access interface od]1:8OF  
x^!LA,`j  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException O['5/:-  
{ 'X1/tB8*  
this.sURL = sURL; qyY]: (8  
this.nStartPos = nStart; Q|W~6  
this.nEndPos = nEnd; RjG=RfB'V  
nThreadID = id; /8s>JPXKH[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :stA]JB# w  
} ne'Y{n(8%  
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2~W8tv0^b2  
public void run() |F?/L>  
{ `&o>7a;  
while(nStartPos < nEndPos && !bStop) d
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{ h[j(@P  
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try{ E>x,$w<?  
URL url = new URL(sURL); &v&e-|r8;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "I
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httpConnection.setRequestProperty("User-Agent","NetFox"); "I&,':O+  
String sProperty = "bytes="+nStartPos+"-"; PQ4)k
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httpConnection.setRequestProperty("RANGE",sProperty); n~v*  
Utility.log(sProperty);

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InputStream input = httpConnection.getInputStream(); l=ZX9<3  
//logResponseHead(httpConnection); JReJlDu  
} !RBH(m%  

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byte[] b = new byte[1024]; a3E.rr;b  
int nRead; MDOP2y`2i  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) +>o} R?xj  
{ JI[9c,N  
nStartPos += fileAccessI.write(b,0,nRead); sGFC?1r?\  
//if(nThreadID == 1) OA8iTn  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fk?(mxx"  
} !1ZrS  
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Utility.log("Thread " + nThreadID + " is over!"); ./E<v  
bDownOver = true; u75(\<{  
//nPos = fileAccessI.write (b,0,nRead); >iFi~)i_4y  
} `ouCQ]tKz  
catch(Exception e){e.printStackTrace ();} Nd61ns(N  
} 5vqh09-FB  
} >Gi*BB  
}1pG0V4  
#)EVi7UP  
//打印回应的头信息 K6@9=_A  
public void logResponseHead(HttpURLConnection con) P)&qy .+E0  
{ b
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for(int i=1;;i++) 2W vf[2Xw  
{ 8YwSaBwO  
String header=con.getHeaderFieldKey(i); p& +w  
if(header!=null) j+QE~L  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "2J
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Utility.log(header+" : "+con.getHeaderField(header)); zT"W(3  
else "gGv>]3  
break; p+O,C{^f  
} #tQ__V   
} `{W>Dy  
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public void splitterStop() Dro2R_j{  
{ b;Uqyc  
bStop = true; +C){&/=#  
} ":,J<|Oy  
ok<!/"RX$  
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} ca!DZ%y  
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/* )6 [d'2  
**FileAccess.java ^%~ux0%^T  
*//文件访问(定位，写) n6s[q-td  
package NetFox; =s$UU15  
import java.io.*; xO2CgqEb  
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public class FileAccessI implements Serializable{ =P\Tk)(`  
B_#U|10et  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 c6f[^Q%#j  
RandomAccessFile oSavedFile; 'r_NA!R  
long nPos; ]9/{  
15tT%TC  
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public FileAccessI() throws IOException ;Vh5nO  
{ 3X A8\Mg  
this("",0); ^=V b'g3P~  
} P gK> Z,  
(n3MbVi3LU  

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public FileAccessI(String sName,long nPos) throws IOException w*7BiZ{s<  
{ 0)T`&u3!  
oSavedFile = new RandomAccessFile(sName,"rw");
25CO_  
this.nPos = nPos; |$aTJ9 Iq:  
oSavedFile.seek(nPos); >,s.!
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} ;^Hg\a  
&$+nuUA  
f+iM_MI  
public synchronized int write(byte[] b,int nStart,int nLen) ^t#W?rxp&  
{ !%s&GD8&l  
int n = -1; {Wp5Ane  
try{ $MB/j6#j  
oSavedFile.write(b,nStart,nLen); Eggdj+  
n = nLen; wEJ) h1=)^  
} s`Z'5J;S  
catch(IOException e) v<c@bDZ>  
{ 5<?s86GHh'  
e.printStackTrace (); |'" 17c&  
} @ATJ|5.gr  
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return n; KoL3CA"N  
} gV-x1s+  
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} \
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[
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}HC6m{vH(  
/* +{F2hEYP  
**SiteInfoBean.java ~KF>Jow?Y  
*/
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package NetFox; I"1H]@"=  
mc
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public class SiteInfoBean { \uTy\KA  
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private String sSiteURL; //Site's URL  [ijK~  
private String sFilePath; //Saved File's Path /degBL+  
private String sFileName; //Saved File's Name UZ` <D/  
private int nSplitter; //Count of Splited Downloading File vOl<  
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public SiteInfoBean() VkCh
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{//nSplitter的缺省值为5 1>"[b8a/  
//default value of nSplitter is 5 jjLwHJ  
this("","","",5); [
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} F}Kkhs {  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 9< $n'g  
{ {+V]saYP  
sSiteURL= sURL; eXdE?j  
sFilePath = sPath; _'"whZ)2  
sFileName = sName; zj9)vr`7  
this.nSplitter = nSpiltter; /\0rRT  
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} tin5.N)"z  
5RysN=czA  

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public String getSSiteURL() >m-VBo  
{ {hmC=j  
return sSiteURL; [_pw|BGp  
} MY]<^/Q  
6?C|pO  
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public void setSSiteURL(String value) X?8EPCk  
{ >ARZ=x[  
sSiteURL = value; +KzbaBK  
} `,O#r0m  
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public String getSFilePath() 1K`7  
{ C=6.~&(  
return sFilePath; X*^^W_LH.  
} $k|:V&6SV  
:p@.a
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public void setSFilePath(String value) nbECEQ:|B  
{ dpPu&m+  
sFilePath = value; kU {>hG4  
} 5
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d}Y\;'2,  
public String getSFileName() BsJ d*-:X  
{ abW[hp  
return sFileName; b-+~D9U<  
} ,_N+t:*#0  
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public void setSFileName(String value) wIbxnn  
{ \@}G'7{  
sFileName = value; fy6<KEea  
} NZTG)<  
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}^@Q9<P^E  
public int getNSplitter() iaAj|:  
{ IOjp'6Yr  
return nSplitter; 5x=aJl;G  
} E<~Fi.M;\  
+'ZJ]  
>OLKaghV.5  
public void setNSplitter(int nCount) ,DZoE~  
{ Biva{'[m  
nSplitter = nCount; RI[=N:C^  
} #aeKK7[  
} 3!H&bOF  
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/* U{JD\G8m  
**Utility.java FoNkISzW  
*/ ~v$1@DQ}  
package NetFox; ,Hzz:ce  
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public class Utility { ZR,"w  
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public Utility() M&v;#CV  
{ j TyR+#Wn  
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} @|2L>N  
4!</JZX~$  
//线程睡眠 bih%hqny  
public static void sleep(int nSecond) ms]r1x"  
{ Sf>#Zqj/  
try{ cEK<CV  
Thread.sleep(nSecond); `B A'a" $  
} F{*h~7D-|  
catch(Exception e) 'nMj<:0wlD  
{ 6L!/#d0  
e.printStackTrace (); \2c3Nsra  
} a$
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} ++=f7yu  
3n!f'" T  
//日志 q?
* z<)#  
public static void log(String sMsg) z8@[]6cW  
{ K7-z.WTUR  
System.err.println(sMsg); 8)o%0#;0B  
} hE;|VSdo  
cp)BPg  
*/6lyODf  
public static void log(int sMsg) +L,V_z  
{ +7KRoF|  
System.err.println(sMsg); ;H4s[#K  
} !\}X?Gf  
} B" 0a5-pkr  
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/* K0usBA  
**TestMethod.java rHa*WA;TE  
*/ z@21Z`,  
package NetFox; L+X:M/)  
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public class TestMethod { II'"Nkxd  
9Rm\@E [  
I !J'  
public TestMethod() jf^BEz5  
{ ///xx/weblogic60b2_win.exe EvKzpxCh  
try{ X=KC+1e  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); FTQNS8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); KDS}"/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); N`HiNb [  
fileFetch.start(); [0n[\& 0  
} jcbq#  
catch(Exception e){e.printStackTrace ();} /& W&  
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} &<LBz|  
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public static void main(String[] args) ^m/7TwD  
{ ^~;"$=Wf  
new TestMethod(); 7|PB6h3  
} Ii&\LJ  
} RG.wu6Av  
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