http断点续传简单实现（java)

/* rcF;Lp :  
**SiteFileFetch.java QKE$>G  
*/ nwOr  
package NetFox; |hiYV  
import java.io.*; +}I[l,,xy  
import java.net.*; h" P4  
j/#kO?  
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public class SiteFileFetch extends Thread { [qIi_(%o  
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SiteInfoBean siteInfoBean = null; //文件信息Bean !5?#^q  
long[] nStartPos; //开始位置 nyw,Fu  
long[] nEndPos; //结束位置 Zo-E0[9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ^.nvX{H8~=  
long nFileLength; //文件长度 7$8
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boolean bFirst = true; //是否第一次取文件 jtS+y)2  
boolean bStop = false; //停止标志 gD
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File tmpFile; //文件下载的临时信息 q4xB`G  
DataOutputStream output; //输出到文件的输出流 67<zBw2  
4)]g=-3  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Olj]A]v}  
public SiteFileFetch(SiteInfoBean bean) throws IOException ^
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{ N#bWMZ"  
siteInfoBean = bean; (=QaAn,,R  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 7I&7YhFI  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); DcQ^V4_  
if(tmpFile.exists ()) ]^3_eHa^d  
{ \Y Cj/tG8  
bFirst = false; zb?wlfT  
read_nPos(); I{_St8  
} o%Vf#W  
else -=Q_E^'  
{ S/G,A,"c  
nStartPos = new long[bean.getNSplitter()]; ed'}ReLK  
nEndPos = new long[bean.getNSplitter()]; f0IljY!.  
} 83412@&  
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} ,b-wo  
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public void run() 5caYA&R  
{ N>/*)Frt  
//获得文件长度 [YHvyfk~_  
//分割文件 zv@'x nY]  
//实例FileSplitterFetch ojs&W]r0Z  
//启动FileSplitterFetch线程 i\3BA"ZX  
//等待子线程返回 -102W{V/T  
try{
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if(bFirst) j+Y4>fL$  
{ Gqk"%irZ  
nFileLength = getFileSize(); }<2F]UuR  
if(nFileLength == -1) a_
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{ }(ay(  
System.err.println("File Length is not known!"); Te[[x
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} j /)cdP  
else if(nFileLength == -2) pEH[fA]  
{ ?OZbns
~  
System.err.println("File is not access!"); S4qh8c  
}
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else ]N!SG@X+  
{ 7Kk rfJqN  
for(int i=0;i<nStartPos.length;i++) }h
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{ i_`YZ7Hxp
 
nStartPos = (long)(i*(nFileLength/nStartPos.length)); DECX18D  
} "sAR<5b  
for(int i=0;i<nEndPos.length-1;i++) 7/PHg)&  
{ a}i{b2B  
nEndPos = nStartPos[i+1]; '8*gJ7]  
}  7z<!2  
nEndPos[nEndPos.length-1] = nFileLength; /nv1
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} reu[}k~
  
} IH\k_Yf#u  
iBp 71x65  
)P|%=laE8  
//启动子线程 >z>UtT:  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Mky$#SI11  
for(int i=0;i<nStartPos.length;i++) zesEbR)j  
{ *VHBTO9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4TwU0N+>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), rJ\A)O+Mq(  
nStartPos,nEndPos,i); "*+epC|ks  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *9j9=N?  
fileSplitterFetch.start(); Xuh_bW&zF  
} *n}9_V%  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xBgf)'W_Z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); U|{WtuR  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", D.*JG7;=Z  
nEndPos = " + nFileLength); 3C_g)5 _:  
// fileSplitterFetch[nPos.length-1].start(); VZAdc*X  
Zr}`W\  
3-o ]H'6  
//等待子线程结束 (g7nMrE$j  
//int count = 0; JGj_{|=:  
//是否结束while循环 <(BAws(X  
boolean breakWhile = false; YLSG 5vF+  
3qpkMu3  
Ql
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while(!bStop) OQ+?nB  
{ 2i,Jnv=sR  
write_nPos(); aj(M{gFq~  
Utility.sleep(500); JYv&It  
breakWhile = true; ZmmuP/~2K  
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for(int i=0;i<nStartPos.length;i++) HS(
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{ y{j>4g$:z  
if(!fileSplitterFetch.bDownOver) t&eD;lg :  
{ Q96g7[  
breakWhile = false; zN2sipJS8  
break; )B}]0`z:P  
} 1+y&n?  
} \F1nEj  
if(breakWhile) cgz'6q'T  
break; }PED#Uv  
^1*p]j(  
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//count++; ~-W.yg6D{  
//if(count>4) ioa 1n=j  
// siteStop(); V
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} Jt)<RMQ^R  
=602%ef\  
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System.err.println("文件下载结束！"); ,(c="L4[  
} !kV?h5@Bo  
catch(Exception e){e.printStackTrace ();} l" sR\`~  
} }DZkCzK  
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jWU)y)$  
//获得文件长度 ?nt6vqaV  
public long getFileSize() $m
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{ X='4N<  
int nFileLength = -1; 2ZE4^j|  
try{ .Bi7~*N  
URL url = new URL(siteInfoBean.getSSiteURL()); m|f|u3'z$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (
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httpConnection.setRequestProperty("User-Agent","NetFox"); \H" (*["&  
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int responseCode=httpConnection.getResponseCode(); *-P@|eg  
if(responseCode>=400) B"Fg`s+]U  
{ 4tu2%Og)?  
processErrorCode(responseCode); >Zr/U!W*?  
return -2; //-2 represent access is error Pc4sReo'  
} )L#I#%  
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'fVk1Qj^  
String sHeader; GGLVv)  
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for(int i=1;;i++) w6wXe_N+M  
{ OKf/[hyu  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ol:_2G2xQ  
//Utility.log(in.readLine()); 
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sHeader=httpConnection.getHeaderFieldKey(i); aqyXxJS8  
if(sHeader!=null) P,>#  
{ Wg$MKc9Vy[  
if(sHeader.equals("Content-Length")) pkxW19h*0  
{ CV& SNA  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 90ORx\Oeo  
break; 4Yn*q~f  
} q-!m|<Z  
} dvXu?F55  
else lq%s/l  
break; #[i({1`^L  
} xknP `T  
} *sw$OnVb  
catch(IOException e){e.printStackTrace ();} >G-D& A+  
catch(Exception e){e.printStackTrace ();} h,#AY[Q  

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Utility.log(nFileLength); Af -{'  
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return nFileLength; EL+}ab2S  
} M@gm.)d  
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4)"jg[  
//保存下载信息（文件指针位置） N*$Q(K  
private void write_nPos() e{?~m6  
{ 5q8bM.k\7N  
try{ ].Et&v  
output = new DataOutputStream(new FileOutputStream(tmpFile)); \?GMtM,  
output.writeInt(nStartPos.length); 3-Ti'xM  
for(int i=0;i<nStartPos.length;i++) .IYE"0)wJ  
{ yt<K!=7&  
// output.writeLong(nPos); ^ 5UIbA(  
output.writeLong(fileSplitterFetch.nStartPos); Qb SX'mx<  
output.writeLong(fileSplitterFetch.nEndPos); c5t?S@b  
} "0]i4d1l  
output.close(); U9;AU]A  
} Uq[
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catch(IOException e){e.printStackTrace ();} gGZ$}vX  
catch(Exception e){e.printStackTrace ();} GbM
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} zx\?cF  
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z}pdcQl#
 
//读取保存的下载信息（文件指针位置） l9SbuT$U  
private void read_nPos() hx:x5L>  
{ \Mi y+<8$  
try{ 9 s>JdAw?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); XLzHm&;  
int nCount = input.readInt(); ~A6QX8a  
nStartPos = new long[nCount]; 0_%u
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nEndPos = new long[nCount]; 3|@Ske1%Y  
for(int i=0;i<nStartPos.length;i++) Jj([O2Eq$  
{ @=@WRPGM*9  
nStartPos = input.readLong(); 5$jKw\FF=  
nEndPos = input.readLong(); lJ}lO,g  
} ;zp0,[r  
input.close(); g y&B"`  
} 7 bpV=  
catch(IOException e){e.printStackTrace ();} :.Np7[~{  
catch(Exception e){e.printStackTrace ();} 'KXvn0
 
} tTP"*Bb  
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private void processErrorCode(int nErrorCode) f4:gD*YT  
{ /tV)8pEj  
System.err.println("Error Code : " + nErrorCode); PCD1I98  
} Pirc49c  
fpzC#  
b~cN#w #  
//停止文件下载  @4H*kA  
public void siteStop() WzZb-F  
{ Z.rKV}yjY  
bStop = true; 3VKArv-  
for(int i=0;i<nStartPos.length;i++) mNs&*h}  
fileSplitterFetch.splitterStop(); 7zy6`OP  
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}  &grT}  
} H{9di\xnEm  
//负责部分文件的抓取 ^TnBtIU-B  
**FileSplitterFetch.java p"Fj6T2  
*/ LL.YkYu  
package NetFox; q(_pk&/  
4WDh8U  
7X1T9'jI2  
import java.io.*; KLlW\MF1  
import java.net.*; *qGxQ?/  
j@Z4(XL  
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public class FileSplitterFetch extends Thread { lS9rgq<n  
P b2exS(  
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String sURL; //File URL %?R}sUo  
long nStartPos; //File Snippet Start Position >8HcCG  
long nEndPos; //File Snippet End Position -x@mS2  
int nThreadID; //Thread's ID kcI3pmgj  
boolean bDownOver = false; //Downing is over Oe*emUX7  
boolean bStop = false; //Stop identical EubF`w$KWX  
FileAccessI fileAccessI = null; //File Access interface .J'}qkz~  
X >C*(/a  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException jj.iW@m  
{ (B]rINY|  
this.sURL = sURL; mq su8ti  
this.nStartPos = nStart; h0d;a  
this.nEndPos = nEnd; 1Y\g{A"  
nThreadID = id; kC0F@'D  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 )"wWV{k  
} -AJe\ J 2  
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"{j4?3f)  
public void run() $#8dtF  
{ ?nCG:\&;'=  
while(nStartPos < nEndPos && !bStop) mKQ!@$*  
{ > QDmSy*&  
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gI<TfcC  
try{ 5fA<I _ D  
URL url = new URL(sURL); h /@G[5E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zT*EpIa+LS  
httpConnection.setRequestProperty("User-Agent","NetFox"); vc5g4ud  
String sProperty = "bytes="+nStartPos+"-"; :WJ[a#  
httpConnection.setRequestProperty("RANGE",sProperty); STL&ZO  
Utility.log(sProperty); O2-9Oo@#,  
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InputStream input = httpConnection.getInputStream(); fOtL6/?  
//logResponseHead(httpConnection); 8:|F'{<<b  
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byte[] b = new byte[1024]; |Xlpgdiu  
int nRead; 4(f[Z9 iZ]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) F/IXqj  
{ B{PI&a9~s%  
nStartPos += fileAccessI.write(b,0,nRead); M6[&od  
//if(nThreadID == 1) &2d^=fih  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
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} bb`GV  
{.K>9#^m  
4U*J{''L  
Utility.log("Thread " + nThreadID + " is over!"); Xk8+m>   
bDownOver = true; O=?WI   
//nPos = fileAccessI.write (b,0,nRead); 67wY_\m9I  
} =c"`>Vi@d  
catch(Exception e){e.printStackTrace ();} ba^B$$?Bo  
} o['
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} RtwlPz<~S  
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4p\<b8(9>  
//打印回应的头信息 AK]{^Hv
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public void logResponseHead(HttpURLConnection con) @`^+XPK\  
{ 4Z12Z@A#7  
for(int i=1;;i++) Y?a*-"  
{ AKk6kI8F  
String header=con.getHeaderFieldKey(i); r({!ejT{U  
if(header!=null) WwG78b-OA  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); xDD3Y{K  
Utility.log(header+" : "+con.getHeaderField(header)); s<Px au+A  
else >>oR@  
break; mrX 2w  
} |WqEJ*$,  
} %xF j;U?  
/n;Ll](ri  
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public void splitterStop() `?r]OVe{y  
{ S
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bStop = true; ErIAS6HS'  
} U
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} "uf*?m3  
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/* Z M_ 6A1  
**FileAccess.java ywW
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*//文件访问(定位，写) qKNX^n;  
package NetFox; Y7
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import java.io.*; ChO?Lm$y  
uTTM%-DMHT  
.@KpN*`KH  
public class FileAccessI implements Serializable{ U+:oy:mz  
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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 4gbi?UAmX  
RandomAccessFile oSavedFile; z(V?pHv+  
long nPos; 6$c,#%Jt*  
7ADh  
e&%m[:W:<  
public FileAccessI() throws IOException |TM&:4D]^  
{ |<tZ|  
this("",0); XN65bq  
} b Lag&c)  
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$.{CA-~%[  
public FileAccessI(String sName,long nPos) throws IOException KzD5>Xf]4$  
{ J%}9"Q5  
oSavedFile = new RandomAccessFile(sName,"rw"); <q|IP_  
this.nPos = nPos;
Q M7z .  
oSavedFile.seek(nPos); x}Qet4vV  
} X{KWBk.1  
?g9mDe;k  
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public synchronized int write(byte[] b,int nStart,int nLen) 6QS[mWU  
{ !9|)v7}  
int n = -1; YF/@]6j  
try{ B~zP!^m  
oSavedFile.write(b,nStart,nLen); oEPO0O  
n = nLen; %
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} 7 +A-S9P)  
catch(IOException e) )P4#P2  
{ Vfew )]I  
e.printStackTrace (); ]yu,YZ@7  
} L$zI_ z  
!#cZ!  
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return n; 5"(AqXoq  
} t95hI DtD  
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} nTrfbK@  
<qZ"W6&&  
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/* $tvGS6p>  
**SiteInfoBean.java E-h`lDoJ  
*/ lsmzy_gV7  
package NetFox;
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. 2_t/2  
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public class SiteInfoBean { 47I5Y5  
,])@?TJb@  
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private String sSiteURL; //Site's URL AU1P?lk  
private String sFilePath; //Saved File's Path %-"?  
private String sFileName; //Saved File's Name ),`MAevp  
private int nSplitter; //Count of Splited Downloading File bh=d'9B@&J  
7O5`&Z'-  
/Z<"6g?  
public SiteInfoBean() N{n}]Js1D-  
{//nSplitter的缺省值为5 QrDrdA  
//default value of nSplitter is 5 $IUP;  
this("","","",5); 9R.IYnq  
} i gzISYC_  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Db({k,P'Y  
{ GEP YSp  
sSiteURL= sURL; 'N,3]Soi  
sFilePath = sPath; HN>eS Y+  
sFileName = sName; %Fb"&F^7  
this.nSplitter = nSpiltter; oQ!}@CaN|  
J)(H-xvV  
&rj6<b1A  
} Ne/jvWWN  
/:dVW"A|  
#I9|>XE1  
public String getSSiteURL() DoWY*2E  
{ G\h8j*o  
return sSiteURL; QQ@, v@j5  
} G}i\UXFE  
, 6\i  
>VP\@xt(R[  
public void setSSiteURL(String value) #V-qS/ q"  
{ 9,5v%HZ  
sSiteURL = value; ri~dWx  
} `9Ngax=
_  
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public String getSFilePath() G~)jk+Qq  
{ _J&u{  
return sFilePath; rPK?pJ  
} GN{\ccej  
)<
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public void setSFilePath(String value) Rz`<E97-  
{ '.~vN L+ O  
sFilePath = value; DMcvu*A  
} xTD6?X'4  
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public String getSFileName() 5WP[-J)  
{ 9}X3Q!iFb  
return sFileName; mL+}Ka  
} Ndi'b_Sh\  
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public void setSFileName(String value) P,h@F+OZN  
{ _ %&"4bm.  
sFileName = value; )ACa0V>*p  
} vJGxD\h  
v Xio1hu  
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public int getNSplitter() 8q7KqYu  
{ <t]c'  
return nSplitter; EBzg<-?o  
} "r cPJX  
<)Kjf/x  
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public void setNSplitter(int nCount) i40r}?-  
{ KtEMH  
nSplitter = nCount; i[3$Wi$  
} *-+~H1tP  
} qCgP8U/jv  
&%u,b~cL?  
(]1le|+  
/* >jl"Yr#  
**Utility.java |nry^zb  
*/ @{I55EQ]  
package NetFox; idO3/>R [  
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public class Utility { ie.cTTOI  
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public Utility() 5tq$SF42X  
{ MiRH i<g0  
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@D"|Jq=6P  
} [9(B;;R@  
L$jyeFB5  
//线程睡眠 ;SC|VcbyH  
public static void sleep(int nSecond) ;o^m"I\y  
{ G#@<bg3  
try{ ;k/0N~  
Thread.sleep(nSecond); ^;@Bz~Z  
} '3hvR
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catch(Exception e) ^* DKF  
{ :+Dn]:\  
e.printStackTrace (); KAsS= `  
} <Isr  
} y Fp1@*ef  
Ds}6{']K  
//日志 Wnf`Rf)1z  
public static void log(String sMsg) |=%$7b\C  
{ a}>GQu*y  
System.err.println(sMsg);
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} ae!_u \$  
}f-rWe{gs>  
IL
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public static void log(int sMsg) W2^eE9  
{ cuKgO{.GH  
System.err.println(sMsg); $^ >n@Q@&L  
} V;:A&  
} b/5~
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q0c)pxD%
`  
/* i;dr(c/ft  
**TestMethod.java X4/r#<Da  
*/ =~EQ3uX  
package NetFox; 5~[Fh2+  
t]&n_]`{.  
^9{ 2  
public class TestMethod { KPO((G0&  
lJYv2EZ  
\uPT-M*  
public TestMethod() 6|jE3rHw  
{ ///xx/weblogic60b2_win.exe 3t_5Xacj  
try{ X*Q7Yu  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); qob!!A14p  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Bf* F^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); SfR!q4b=  
fileFetch.start(); pEaH^(I*  
} }oU&J81  
catch(Exception e){e.printStackTrace ();} S7SPc   
(6A{6_p  
[R:O'AP}@}  
} ix/uV)]k`  
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public static void main(String[] args) ?PQiVL  
{ R1m18GHQ  
new TestMethod(); ,}|V'y  
} ?<}qx`+%Q  
} .ZJh-cd  
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