http断点续传简单实现（java)

/* '?~k`zK  
**SiteFileFetch.java E0Vl}b  
*/ ;U|^Tsuc`  
package NetFox; h?:lO3)TL=  
import java.io.*; zAxwM-`  
import java.net.*; q#RVi8('  
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public class SiteFileFetch extends Thread { ;mLbJT   
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SiteInfoBean siteInfoBean = null; //文件信息Bean [-sE:O`yt  
long[] nStartPos; //开始位置 [N/[7Q/y  
long[] nEndPos; //结束位置 u= K
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 snBC +`-  
long nFileLength; //文件长度 <'4DMZ-G  
boolean bFirst = true; //是否第一次取文件 w%1B_PyDg  
boolean bStop = false; //停止标志 X~Li`  
File tmpFile; //文件下载的临时信息 1lNg} !)[K  
DataOutputStream output; //输出到文件的输出流 iD|"}}01  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） t _Q/v
 
public SiteFileFetch(SiteInfoBean bean) throws IOException {=,?]Z+  
{ rY>{L6d  
siteInfoBean = bean; 1
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ` m`Sl[
6  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Nky%v+r  
if(tmpFile.exists ()) 5}R/C{fs  
{ +6!.)Ea=  
bFirst = false; e3wFi,/@  
read_nPos(); 5CkM0G`  
} P$)9osr  
else x c-=;|s  
{ |Js96>B:  
nStartPos = new long[bean.getNSplitter()]; m)q;eQs  
nEndPos = new long[bean.getNSplitter()]; (iK0T.  
} sDCa&"6+@  
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} HPT9B?^  
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public void run() s&lZxnIjc  
{ %f@VOSs  
//获得文件长度 ~"5WQK`@  
//分割文件 S{z%Q  
//实例FileSplitterFetch .J~iRhVOF  
//启动FileSplitterFetch线程 z1LATy  
//等待子线程返回 ^n<p#0)+a  
try{ m\4jiR_o  
if(bFirst) $Tq-<FbM)  
{ 2&]UFg:8Q  
nFileLength = getFileSize(); EG0NikT?  
if(nFileLength == -1) / GJ"##<  
{ j*$GP'Df3  
System.err.println("File Length is not known!"); {P(Z{9u%  
} oa`,|dA"  
else if(nFileLength == -2) D|Z,eench  
{ QHsS|\u  
System.err.println("File is not access!"); jjz<V(Sk  
} "31GC7  
else }qW%=;!  
{ `2NL'O:  
for(int i=0;i<nStartPos.length;i++) 8\y%J!b  
{ gzP(LfI5  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); N`grr{*_  
} 0pu])[P]_[  
for(int i=0;i<nEndPos.length-1;i++) -2tX
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{ Eln"RKCt}9  
nEndPos = nStartPos[i+1]; {:Z#8dGe  
} S
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nEndPos[nEndPos.length-1] = nFileLength; [8SW0wsk  
} 'mug,jM  
} ,I@4)RSAH|  
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lV$U!v:b  
//启动子线程 4%p5X8|\ih  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _?@>S7-  
for(int i=0;i<nStartPos.length;i++) &.o}(e:]  
{ ~@bCSOIy  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?i(Tc
!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), pp#Kb 2*  
nStartPos,nEndPos,i); w])bQ7)  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); gA!-F}x$  
fileSplitterFetch.start(); &6MGPh7T  
} N"T~U\R  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _:M6~XHo  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); pLBp[GQ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", J*,Ed51&7  
nEndPos = " + nFileLength); c1CP12  
// fileSplitterFetch[nPos.length-1].start(); Z5-"a?{Y  
$}OU~d1q  
0c7&J?"wE  
//等待子线程结束 f;pR8  
//int count = 0; UY{ Uo@k9x  
//是否结束while循环 $1\<>sJH  
boolean breakWhile = false; \p@,+ -gX  
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}PyAmh$@  
while(!bStop) >}O1lsjW:z  
{ aiw~4ix  
write_nPos(); nf/iZ &  
Utility.sleep(500); %nOBsl
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breakWhile = true; HC4ad0Gs+{  
>}u?{_s *0  
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for(int i=0;i<nStartPos.length;i++) b\gl9"X  
{ XT~JP
  
if(!fileSplitterFetch.bDownOver) ;b cy(Fp,\  
{ 4VaUa8 D  
breakWhile = false; N iNZh;  
break; yKOf]m>#  
} YcRjbF,|6  
} ?8! 4!P%n  
if(breakWhile) '/;#{("  
break; *-_` xe  
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//count++; #B`"B  
//if(count>4) Cl<`uW3  
// siteStop(); AUS?Pt[w  
}  vxr3|2`  
:XBeGNI*#  
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System.err.println("文件下载结束！"); StP6G ]x  
} fBD5K3  
catch(Exception e){e.printStackTrace ();} yql+N[  
} og.dYs7W4  
Zf]d'oW{/  
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//获得文件长度 Lkk'y
})/  
public long getFileSize() yn!LJT[~2  
{ c !P9`l~MQ  
int nFileLength = -1; 3
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try{ ?)4|WN|c_  
URL url = new URL(siteInfoBean.getSSiteURL()); "Oh-`C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $
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httpConnection.setRequestProperty("User-Agent","NetFox"); Yq`r>g  
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int responseCode=httpConnection.getResponseCode(); o0s+ roiD  
if(responseCode>=400) LL9Mty,  
{ ]wa?~;1^&  
processErrorCode(responseCode); MV9{>xX  
return -2; //-2 represent access is error Jev@IORN\  
} ?@_3B]Fs  
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6n%^ U2H/-  
String sHeader; "M_X9n_  
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nm %ka4  
for(int i=1;;i++) Rc?wIL)  
{ S:rW}rJ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); RFg$N@g,  
//Utility.log(in.readLine()); RU_=VB %  
sHeader=httpConnection.getHeaderFieldKey(i); zMtK_ccQ  
if(sHeader!=null) jh\q2E~,`  
{ HX+'{zm]  
if(sHeader.equals("Content-Length")) SRM[IU  
{ _u{D#mmO  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); s(Kf%ZoE  
break; GE~mu76%  
} ]Z<{ ~  
} s'~_pP  
else 2c8,H29  
break; Om>6<3n  
} JWMIZ{/M  
} kwGj7'  
catch(IOException e){e.printStackTrace ();} )F4er'  
catch(Exception e){e.printStackTrace ();} .t"s>jq 1  
! ~&X1,l1*  
IO^O9IEx,  
Utility.log(nFileLength); oPzt1Y  
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return nFileLength; kz,Nz09}W  
} Sm+Ek@Ax  
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 9l{r&]  
//保存下载信息（文件指针位置） |P5?0{  
private void write_nPos() 86IAAO`#  
{ {_^sR}%]F  
try{ :l
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output = new DataOutputStream(new FileOutputStream(tmpFile)); *RxbqB-  
output.writeInt(nStartPos.length); mqq~&nI  
for(int i=0;i<nStartPos.length;i++) 8.Y6r  
{ a}jaxGy  
// output.writeLong(nPos); tJHzhH)  
output.writeLong(fileSplitterFetch.nStartPos); KkAk(9Q/3  
output.writeLong(fileSplitterFetch.nEndPos); .~W7{SY[  
} "p2PZ)|  
output.close(); q3scz  
} pN*>A^  
catch(IOException e){e.printStackTrace ();} %@H;6   
catch(Exception e){e.printStackTrace ();} 4^AE;= Q  
} "=yaeEp  
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//读取保存的下载信息（文件指针位置） 4~G9._  
private void read_nPos() Z"e|DP`  
{ tV#x{DN  
try{ I!# 42~\  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Gt6$@ji4u  
int nCount = input.readInt(); tQ?? nI2  
nStartPos = new long[nCount]; oB_{xu$6|  
nEndPos = new long[nCount]; ym(r;mj!  
for(int i=0;i<nStartPos.length;i++)  U]e;=T:3  
{ uo 7AU3\  
nStartPos = input.readLong(); HpNf f0c  
nEndPos = input.readLong(); T!v%NZj3  
} \P{VJ^)0  
input.close(); 1C.<@IZ  
} H~||]_q|  
catch(IOException e){e.printStackTrace ();} [0MVsc=  
catch(Exception e){e.printStackTrace ();} Ae`K9  
} $qIMYX  
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private void processErrorCode(int nErrorCode) !y4o^Su[  
{ "'6KQnpZ  
System.err.println("Error Code : " + nErrorCode); O$#`he/jm  
} ajkRL|^  
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=C<_rBY  
//停止文件下载 (F$q|qZ%  
public void siteStop() {:{NK%  
{ GbStqR~^#  
bStop = true; "hs`Y4U  
for(int i=0;i<nStartPos.length;i++) /A<L  
fileSplitterFetch.splitterStop(); EVRg/{X  
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} 1[X+6viE  
} bS* "C,b~s  
//负责部分文件的抓取 K[T?--H  
**FileSplitterFetch.java 5;dnxhf  
*/ Du[$6  
package NetFox; j>
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import java.io.*; rC/m}`b  
import java.net.*; FeSe^^dW  
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public class FileSplitterFetch extends Thread { /pX\)wi  
e:!&y\'"9  
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String sURL; //File URL LA"`8  
long nStartPos; //File Snippet Start Position Bv!j.$0d{  
long nEndPos; //File Snippet End Position /Pi{Mv eZM  
int nThreadID; //Thread's ID (B,CL222x  
boolean bDownOver = false; //Downing is over hua{g_  
boolean bStop = false; //Stop identical ;'R{b$B;|  
FileAccessI fileAccessI = null; //File Access interface ~{U~9v^v(  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException A9$q;8= <  
{ qBKIl= ne  
this.sURL = sURL; t[iE >  
this.nStartPos = nStart; 0P%(4t$pd  
this.nEndPos = nEnd; gt'0
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nThreadID = id; i(L;1 `  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 obaJT"1  
} ha3 Qx  
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public void run() 6^UeEmjc  
{ v

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while(nStartPos < nEndPos && !bStop) 0'z$"(6D  
{ !*+~R2&b
 
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try{ K~v"%sG{`  
URL url = new URL(sURL); *4]I#N  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); x:
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httpConnection.setRequestProperty("User-Agent","NetFox"); F/&Z1G.  
String sProperty = "bytes="+nStartPos+"-"; ",`fGu )  
httpConnection.setRequestProperty("RANGE",sProperty); y=5s~7]  
Utility.log(sProperty); x1Z?x,-D"  
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InputStream input = httpConnection.getInputStream(); N<Ti]G  
//logResponseHead(httpConnection); !t~S.`
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byte[] b = new byte[1024]; q
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int nRead; @x"vGYKd  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) LnrR#fF]Z  
{ xr)kHJ:v  
nStartPos += fileAccessI.write(b,0,nRead); c?>Q!sC  
//if(nThreadID == 1) d8dREhK&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); XSn^$$S  
} GfL}f9  
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Utility.log("Thread " + nThreadID + " is over!"); ?<xGO@b .  
bDownOver = true; L;E9"7
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//nPos = fileAccessI.write (b,0,nRead);
[ ecYpE<  
} 2/qfK+a  
catch(Exception e){e.printStackTrace ();} ]}~*uT}>  
} i nF&Pv  
} O'A''}M  
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URX>(Y}g9^  
//打印回应的头信息 c,X\1yLy  
public void logResponseHead(HttpURLConnection con) `m@06Q  
{ yhgHwES"  
for(int i=1;;i++) ~\:+y  
{ O^F%ssF8  
String header=con.getHeaderFieldKey(i); AEOo]b*&d  
if(header!=null) Aj SIM.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~*THL0]~  
Utility.log(header+" : "+con.getHeaderField(header)); ,?<jue/bd  
else OUnt?[U\  
break; o&fAnpia=  
} li%=<?%T  
} ^e<0-uM"s  
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public void splitterStop() H_vOZ0  
{ p\b:uy6#  
bStop = true; .nKyB'uV  
} [[oX$0Fp\!  
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} l3b$b%0'  
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/* CPFd 33  
**FileAccess.java -O^b  
*//文件访问(定位，写) ZTMzL%i  
package NetFox; T_y 'cvh  
import java.io.*; 6=MejT  
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public class FileAccessI implements Serializable{ J$j&j`  
!gW$A-XD  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 pj?+cy v~  
RandomAccessFile oSavedFile; @X\Sh>H  
long nPos; ~EpMO]I  
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public FileAccessI() throws IOException v^HDR 3I  
{ ?K|PM<A  
this("",0); T{{J' _s5L  
} }i|o":-x+  
'nBJ[$2^  
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public FileAccessI(String sName,long nPos) throws IOException .A&Ey5  
{ m/cbRuPWgP  
oSavedFile = new RandomAccessFile(sName,"rw"); UI_|VU>J  
this.nPos = nPos; %pt ul_(s'  
oSavedFile.seek(nPos); ubj ~ULA  
} *{)[:;  
rm1R^n  
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public synchronized int write(byte[] b,int nStart,int nLen) t A\N$  
{ k2j:s}RHY  
int n = -1; q !EJs:AS  
try{ D2[uex  
oSavedFile.write(b,nStart,nLen); nxA]EFS  
n = nLen; FOM~Uj  
} @HMt}zD  
catch(IOException e) :_p3nb[r  
{ `a3q)}*Y
 
e.printStackTrace (); %
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} E)09M%fe  
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return n; `0=0IPVd  
} o3
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} jf$6{zO6j  
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/* /49PF:$?  
**SiteInfoBean.java r*0a43mC1  
*/ U@ALo  
package NetFox; (|bMtT?"x  
}rn}r4_a  
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public class SiteInfoBean { y@nWa\iG  
w4:n(.;HK  
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private String sSiteURL; //Site's URL o!aKeM~|Es  
private String sFilePath; //Saved File's Path ~SUA.YuF  
private String sFileName; //Saved File's Name n
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private int nSplitter; //Count of Splited Downloading File e\%QHoi>u  
y~SFlv36
  
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public SiteInfoBean() Z?ZcQ[eC  
{//nSplitter的缺省值为5 b+OLmd  
//default value of nSplitter is 5 &Sa<&2W4S  
this("","","",5); OcQ_PE5\  
} zb?wlfT  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) y$r9Y!?s  
{ /A9Mv%zjk  
sSiteURL= sURL; !6@xX08z  
sFilePath = sPath; rPaD#GA[7  
sFileName = sName; 69dFd!G\  
this.nSplitter = nSpiltter; [{}9"zB$x0  
h|!B;D  
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} r{YyKSL1*K  
SR*%-JbA  
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public String getSSiteURL() xv$^%(Ujp  
{ zv@'x nY]  
return sSiteURL; ojs&W]r0Z  
} i\3BA"ZX  
-102W{V/T  

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public void setSSiteURL(String value) j+Y4>fL$  
{ u5H#(&Om  
sSiteURL = value; }<2F]UuR  
} a_
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}(ay(  
Te[[x
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public String getSFilePath() j /)cdP  
{ pEH[fA]  
return sFilePath; ?OZbns
~  
} S4qh8c  

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]N!SG@X+  
public void setSFilePath(String value) 7Kk rfJqN  
{ }h
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sFilePath = value; i_`YZ7Hxp
 
} :54|Z5h|  
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}ebw1G  
public String getSFileName() %b\xRt[0v7  
{ t<ftEJU"'w  
return sFileName; S/~6%uJ  
} r;|Bc$P  
@T;O^rE~N  
6|T{BOW!d  
public void setSFileName(String value) [cXu<vjFM  
{ g_0"T}09(  
sFileName = value; tborRi)  
} n
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wS``Q8K+dM  
iL|*g3`-f  
public int getNSplitter() l2VO=RDiW  
{ ;cp-jY_U  
return nSplitter; O3bK>9<K  
} 7 aDI6G  
S~(4q#Dt-  
&U4]hawbOU  
public void setNSplitter(int nCount) <Cg;l<$`b  
{ ]DmqhK`  
nSplitter = nCount; Qbl6~>T  
} W.MJyem  
} g+ 2SB5 2D  
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JO :m: M  
/* 3C_g)5 _:  
**Utility.java )@R:$l86  
*/ }^`{YD  
package NetFox; Gk[P-%%b /  
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public class Utility { \M>AN Z}  
<(BAws(X  
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public Utility() 3qpkMu3  
{ _JR4 PKtx  
OQ+?nB  
$ZcmE<7k  
} ^jf$V#z0/  
Dcus-,u~  
//线程睡眠 Y] P}7GZ  
public static void sleep(int nSecond) -\UzL:9>  
{ X@~sIUXx9  
try{ {E6W]Mno  
Thread.sleep(nSecond); ?ZDx9*f  
} sv0kksj  
catch(Exception e)
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{ *2
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e.printStackTrace (); 5VG@Q%  
} B@iIj<p~  
} #y>oCB`EM  
cgz'6q'T  
//日志 A]H+rxg  
public static void log(String sMsg) 'O{hr0q}  
{ 5+ fS$Q  
System.err.println(sMsg); >$R-:>~zN  
} jDXmre?  
_ORW'(:Z  
^+GN8LUs  
public static void log(int sMsg) V
8n}"  
{ f_Wn[I{  
System.err.println(sMsg); !^8'LMY<I  
} #e8CuS  
} ,(c="L4[  
!kV?h5@Bo  
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/*
3_33@MM  
**TestMethod.java X,y$!2QI  
*/ %'g/4I  
package NetFox; mY`b|cS3p$  
8\I(a]kM`  
8i:b~y0  
public class TestMethod { JBoo7a1  
<n6/np!  
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public TestMethod() }:jXl!:V  
{ ///xx/weblogic60b2_win.exe 7kJ,;30)  
try{ ?C $_?Qi  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); J41ZQ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); O$&p<~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); n"dT^ g  
fileFetch.start(); ,9A[o`b  
} PMrvUM62  
catch(Exception e){e.printStackTrace ();} Nm;ka&'  
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5  
MaM
s(  
} *S=v1 s/  
}'@*Olj  
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public static void main(String[] args) IF1?/D"<  
{ #vDe/o+=  
new TestMethod(); g8qN+Gg  
} l7x%G@1#~W  
} qY0Ic5wCY  
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