http断点续传简单实现（java)

/* k\~A\UIYo  
**SiteFileFetch.java ] SErM#$*  
*/ :6
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package NetFox; ,fQs+*j  
import java.io.*; a33SY6.  
import java.net.*; %mv9+WJN.  
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public class SiteFileFetch extends Thread { bO:m^*  
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SiteInfoBean siteInfoBean = null; //文件信息Bean yQ3*~d~U|L  
long[] nStartPos; //开始位置 ;?A?1q8*  
long[] nEndPos; //结束位置 T&5dF9a  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 K
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long nFileLength; //文件长度 ZYBK'&J4m  
boolean bFirst = true; //是否第一次取文件 h>l  
boolean bStop = false; //停止标志 d:x=g i!  
File tmpFile; //文件下载的临时信息 A)X 'We  
DataOutputStream output; //输出到文件的输出流 "E><:_,\  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） !{L6 4qI  
public SiteFileFetch(SiteInfoBean bean) throws IOException dE_I=v  
{ DJF-J#  
siteInfoBean = bean; OcB
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); r$7D;>*O{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); c20'{kH  
if(tmpFile.exists ()) ?b&~(,A{  
{ o#IQz_  
bFirst = false; E7*z.3
  
read_nPos(); *Y2d!9F}Sa  
} :e&P's=
 
else u}[Z=V  
{ zg3q\~  
nStartPos = new long[bean.getNSplitter()]; KLc<c1BZ  
nEndPos = new long[bean.getNSplitter()]; P]pVYX#m  
} D-zqu~f`  
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} Ux2pqPb  
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public void run() aXSTA,%  
{ (aO+7ykRuJ  
//获得文件长度 .-:R mYGR  
//分割文件 [}/\W`C  
//实例FileSplitterFetch S"Q$ Ol"  
//启动FileSplitterFetch线程 oXR%A7  
//等待子线程返回 o,fBOPIN  
try{ @'K+   
if(bFirst) Jk.Ec)w  
{ Ve4!MM@
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nFileLength = getFileSize(); \mt0mv;c
 
if(nFileLength == -1) d45JT?qg&  
{ ?1I0VA']  
System.err.println("File Length is not known!"); Rks3L  
} h4xRRyK  
else if(nFileLength == -2) C?FUc cI  
{ #eqy!QdePf  
System.err.println("File is not access!"); k^pf)*p  
} $=j}JX}z  
else T1@]:`&  
{ YdgaZJs  
for(int i=0;i<nStartPos.length;i++) j
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{ Q6cF<L`bW  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); V9 pKbX  
} rZ~.tT|(  
for(int i=0;i<nEndPos.length-1;i++) ~PT(/L  
{ #du!tx ( _  
nEndPos = nStartPos[i+1]; (aX5VB**  
} zl: 5_u=T  
nEndPos[nEndPos.length-1] = nFileLength; W@^O'&3d  
} c%uX+\-$  
} `]^JOw5o  
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f  
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//启动子线程 3N)
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +3 2"vq)_  
for(int i=0;i<nStartPos.length;i++) Og`6>?>97  
{ zL@ZNH  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xQ `>\f  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), t` R#pQ  
nStartPos,nEndPos,i);  /{.  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bP`.teO\  
fileSplitterFetch.start(); 6'e}!O  
} "%
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yIwAJl7Xf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7P`|wNq  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", K h}Oiw  
nEndPos = " + nFileLength); zR'lQ<u  
// fileSplitterFetch[nPos.length-1].start(); ,y[wS5li  
+8FlDiP  
`0tzQ>ZQq  
//等待子线程结束 TR8
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//int count = 0; {XMF26C#  
//是否结束while循环 /++CwRz@Gm  
boolean breakWhile = false; @)>9l&  
m<>3GF,5bP  
blcd]7nK  
while(!bStop) ]7C=.'Y  
{ ).TQYrs  
write_nPos(); ~+{OSx<S  
Utility.sleep(500); \N\Jny  
breakWhile = true; DiyviH  
'H<0:bQ=I  
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for(int i=0;i<nStartPos.length;i++) ?|8H|LBIr  
{ M`$s dZ"  
if(!fileSplitterFetch.bDownOver) }fW@8ji\  
{ 3_W1)vd{
 
breakWhile = false; %aU4d e^  
break; 6mJa  
} x8Rmap@L.  
} 3T$gT  
if(breakWhile) i0ax`37  
break; m}] bP  
@Y'BqDFlZ  
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//count++; Iaf"j
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//if(count>4) }vkrWy^  
// siteStop(); |->{NUZ{  
} (&4aebkZO  
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System.err.println("文件下载结束！"); +(iM]L$Fw%  
} 12*'rU;*  
catch(Exception e){e.printStackTrace ();} AvdxDN  
} P agzp%m  
d/G`w{H}y  
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//获得文件长度 I"4j152P|  
public long getFileSize() " d3pkY  
{ &Avd  
int nFileLength = -1; JPQ[JD^]  
try{ ID"'`DKxe  
URL url = new URL(siteInfoBean.getSSiteURL()); wSHE~Xx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )A9K
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httpConnection.setRequestProperty("User-Agent","NetFox"); D.H$4[u;j  
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int responseCode=httpConnection.getResponseCode(); tuuc9H4B  
if(responseCode>=400) ;aKdRhDo  
{ i$HaE)qZ  
processErrorCode(responseCode); p#W[he  
return -2; //-2 represent access is error iha{(-  
} & IVwm"  
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String sHeader; ]q DhGt  
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+2!J3{[J  
for(int i=1;;i++) [$_d|Z  
{ D;.O#bS  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); V`$Jan  
//Utility.log(in.readLine()); z5PFppSQ  
sHeader=httpConnection.getHeaderFieldKey(i); GUJ[2/V~A  
if(sHeader!=null) sZ #Ck"n  
{ E]`)  
if(sHeader.equals("Content-Length")) jy`jxOoG~Z  
{ ;hi+.ng_  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); #/zPAcV:  
break; &o$E1;og  
} euO!+9p  
} 7q*L-Xe]k  
else f>i6f@  
break; (SV(L~T_  
} /Fej)WQp  
} @EH:4~  
catch(IOException e){e.printStackTrace ();} @^oOXc,r$  
catch(Exception e){e.printStackTrace ();} 'NF_!D  
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Utility.log(nFileLength); (#FWA<o  
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return nFileLength; 57e'a&}e  
} uj|{TV>v9  
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//保存下载信息（文件指针位置） ^OKCvdS  
private void write_nPos() Szrr
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{ DytH} U"  
try{ kD:O$8[J8  
output = new DataOutputStream(new FileOutputStream(tmpFile)); S0nBX"$u  
output.writeInt(nStartPos.length); 4*W ??(=j  
for(int i=0;i<nStartPos.length;i++) PLR[nB7K  
{ !_rAAY  
// output.writeLong(nPos); /v"u4Ipj  
output.writeLong(fileSplitterFetch.nStartPos); u9rlNmf$  
output.writeLong(fileSplitterFetch.nEndPos); mMm_=cfv  
} ~Emeo&X  
output.close(); 3eQ-P8LS  
} dABmK;  
catch(IOException e){e.printStackTrace ();} g#qt<d}j  
catch(Exception e){e.printStackTrace ();} @ROMHMd}  
} iLw O4i  
$6w[h7  
w!o[pvyR$  
//读取保存的下载信息（文件指针位置） ;rWgt!l  
private void read_nPos() :RR<-N5+  
{ p%~#~5t,  
try{ ,<n >g;  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); xlG/$`Ab  
int nCount = input.readInt(); W(ITs}O  
nStartPos = new long[nCount]; P.
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nEndPos = new long[nCount]; -o*IJQ_  
for(int i=0;i<nStartPos.length;i++) V.5gxr3QqW  
{ 22S4q`j  
nStartPos = input.readLong(); }I<r=?  
nEndPos = input.readLong(); $6.CN#  
} 8B;wn<O  
input.close(); :iJ+ImBpK  
} VE5w!of  
catch(IOException e){e.printStackTrace ();} Lbk?( TL  
catch(Exception e){e.printStackTrace ();} 3a #2 }  
} ^T`)ltI]V  
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private void processErrorCode(int nErrorCode) 3/V&PDC*'  
{ {_QXx  
System.err.println("Error Code : " + nErrorCode); Gqq%q!k&1  
} <a7y]Py  
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8 hx4N  
//停止文件下载 J'9hzag  
public void siteStop() ]b
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{ [2I1W1pd  
bStop = true; c'nEbelE  
for(int i=0;i<nStartPos.length;i++) /tI8JXcUK  
fileSplitterFetch.splitterStop(); n{JBC%^g  
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} _4F(WCco  
} j\& `  
//负责部分文件的抓取 *4#)or  
**FileSplitterFetch.java ,.[T]37  
*/ ;Ak<O[  
package NetFox; p`:hY`P  
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import java.io.*; ZaJg$  
import java.net.*; mne4uW
 
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public class FileSplitterFetch extends Thread { rZ`ob x\S  
9r.Os  
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String sURL; //File URL umZy=KHj  
long nStartPos; //File Snippet Start Position ZGgKCCt  
long nEndPos; //File Snippet End Position KDr?<"2L  
int nThreadID; //Thread's ID 9TRS#iVL+*  
boolean bDownOver = false; //Downing is over -N;$L~`iAt  
boolean bStop = false; //Stop identical l&l&
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FileAccessI fileAccessI = null; //File Access interface UFBggT\  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 5
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{ HwTb753  
this.sURL = sURL; 5/Viz`hsz  
this.nStartPos = nStart; /f_w@TR\{  
this.nEndPos = nEnd; 3lzjY.]Pgv  
nThreadID = id; 9jq}`$S{  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +bpUb0.W  
} R:c$f(aKv%  
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public void run() .4E5{F{~  
{ =K'X:UM  
while(nStartPos < nEndPos && !bStop) AjBwj5K  
{ _N!L?b83P  
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try{ y%%D="  
URL url = new URL(sURL); {FRUB(68b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,aOi:aaZRT  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^o&3+s}M  
String sProperty = "bytes="+nStartPos+"-"; GJ"S*30  
httpConnection.setRequestProperty("RANGE",sProperty); q6DuLFatc*  
Utility.log(sProperty); dsck:e5agZ  
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InputStream input = httpConnection.getInputStream(); 50r3Kl0  
//logResponseHead(httpConnection); vN#?>aL  
{Q9?Q?  
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byte[] b = new byte[1024]; jb;!"HC  
int nRead; ]@E_Hx{
S  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) -P
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{ {*utke]}*  
nStartPos += fileAccessI.write(b,0,nRead); n N.6?a  
//if(nThreadID == 1) &V/n!|q<H  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vbEAd)*S  
} .Z%y16)T  
@qj4rt"  
nE.w  
Utility.log("Thread " + nThreadID + " is over!"); 4WCWu}  
bDownOver = true; 1;_tu  
//nPos = fileAccessI.write (b,0,nRead); 7<FI[  
} :/YHU3~Y  
catch(Exception e){e.printStackTrace ();} *_feD+rq  
} o/0cd  
} iF]G$@rbU  
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//打印回应的头信息 9C&Xs nk  
public void logResponseHead(HttpURLConnection con) I`hltJM'  
{ s D
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for(int i=1;;i++) Gy}WZ9{  
{ }!_x\eq^  
String header=con.getHeaderFieldKey(i); Jr|"QRC  
if(header!=null) r'bctFsD  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); sBUK v(U)  
Utility.log(header+" : "+con.getHeaderField(header)); aumWU{j=  
else BK>3rjXi>a  
break; %f[0&)1!.v  
} z+3GzDLy  
} ."`mh&+`  
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public void splitterStop() 9*fA:*T  
{ w:[1,rRvT  
bStop = true; 25EuVj`zL  
} r 0mA  
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} )?_x$GKY  
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/* 2;8I0BH*'  
**FileAccess.java [l~Gwaul>  
*//文件访问(定位，写) ;MSdTHN"  
package NetFox; 72Zp%a=  
import java.io.*; VtM:~|v  
)|52B;yZx  
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public class FileAccessI implements Serializable{ Mw{0A\6  
p7SX,kpt>  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 }jL_/gvgy  
RandomAccessFile oSavedFile; <HYK9{Q  
long nPos; LYTx8  
SNLZU%jan  
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public FileAccessI() throws IOException jVW .=FK  
{ |[6jf!F  
this("",0); Z"ce1cB  
} ?HD eiJkX  
!u)>XS^E
  
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public FileAccessI(String sName,long nPos) throws IOException gteG*pi  
{ 8]G  
oSavedFile = new RandomAccessFile(sName,"rw"); U2hPsF4f  
this.nPos = nPos; #:q$sKQ_$  
oSavedFile.seek(nPos); FJI%+$]  
} wl^7.IR  
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public synchronized int write(byte[] b,int nStart,int nLen) /Kw}R5l  
{ Kp]\r-5UD>  
int n = -1; z2.9l?"rfQ  
try{ .8.4!6~@  
oSavedFile.write(b,nStart,nLen); )># Y,/q  
n = nLen; G`;YB  
} Pn?,56SD=  
catch(IOException e) kdq<)>"  
{ cA,`!dG2,  
e.printStackTrace (); +ConK>;  
} &XvSAw+D@  
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return n; SRP.Mqg9  
} OV~]-5gau  
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} NA :_yA"  
/m"#uC!\  
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/* yuef84~  
**SiteInfoBean.java E%.w6-  
*/ i(Xz3L#(  
package NetFox; v0aV>-v  
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rd
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public class SiteInfoBean { G5l?c@o  
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private String sSiteURL; //Site's URL CjQ)Bu*
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private String sFilePath; //Saved File's Path "e-RV  
private String sFileName; //Saved File's Name "VIoVu  
private int nSplitter; //Count of Splited Downloading File KfPYH\0  
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public SiteInfoBean() q HU}EEv  
{//nSplitter的缺省值为5 w=;Jj7}L  
//default value of nSplitter is 5 %&Fsk]T%:  
this("","","",5); z+5ZUS2~&  
} `)aIFAW  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $n><p>`  
{ }G/#Nb)  
sSiteURL= sURL; )%zOq:{\5  
sFilePath = sPath; [^D~T  
sFileName = sName; #F^0uUjq  
this.nSplitter = nSpiltter; ~K2.T7=  
I$y6N"|  
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} sw\O\%^  
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public String getSSiteURL() hI#1Ybl  
{ }x~1w:zHd  
return sSiteURL; 
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} wCitQ0?  
NZQl#ZJH:  
2zPO3xL,  
public void setSSiteURL(String value) o,q47W=7$  
{ a5dc#f Kf  
sSiteURL = value; o0)k5P~<~  
} l~C=yP(~  
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public String getSFilePath() `zP{E T_Y  
{ 9 *+X^q'  
return sFilePath; w9aLTLv-  
} B)`@E4i  
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public void setSFilePath(String value) q(XO_1W0V  
{ oro^'#ki  
sFilePath = value; DkA@KS1Dq  
} ,7/F?!G!J  
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public String getSFileName() ytyX:e"  
{ P
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return sFileName; isR)^fI|  
} v?L
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public void setSFileName(String value) *Rl
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{ KB5<)[bs  
sFileName = value; 9`FPV`/  
} t,IQ|B&0  
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public int getNSplitter() mzbMX <  
{ JW2~ G!@  
return nSplitter; ]w5j?h"b  
} 17ol %3 M  
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sMDHg
 
public void setNSplitter(int nCount) _0Z8V[  
{ [9H986=  
nSplitter = nCount; d8Sr,t+  
} y3Q2d7G  
} n1Fp$9%  
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/* -oMp@2\e  
**Utility.java *t_JR  
*/ :(TOtrK@  
package NetFox; =C4!h'hz  
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XdV(=PS!a@  
public class Utility { D=_FrEM_IA  
^77X?nDz=h  
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public Utility()
ud$*/ )/  
{ LEJn 1  
O <#H5/Tq  
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} 5~H}%W,P  
;-"'sEu}  
//线程睡眠 %^LwLyoVM  
public static void sleep(int nSecond) w(cl,W/w  
{ cz.,QIt_  
try{ =g^k$ Rc  
Thread.sleep(nSecond); \Pt_5.bTs[  
} $/|2d4O:{  
catch(Exception e) >`)IdX  
{ Xo/0lT  
e.printStackTrace (); 'FC#O%l  
} }~+_|
  
} 7T/hmVi_  
+2Wijrn  
//日志 H^JwaF  
public static void log(String sMsg) -;RW)n^n  
{ }WM!e"  
System.err.println(sMsg); "]kq,j^]  
} $guaUe[x  
yN:U"]glC  
4&}dA^F  
public static void log(int sMsg) ZB'ms[  
{ v?<Tkw ^F  
System.err.println(sMsg); <wj}y0(  
} IRY/0v  
}  .H7xG'$  
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P+(q38f[  
/* jImw_Q  
**TestMethod.java N}X7g0>hV  
*/ %WO4uOi:@  
package NetFox; pUm|e5  
]]!&>tOlI  
!Jk|ha~r  
public class TestMethod { Wo,"$Z6B  
y%@C-:
 
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public TestMethod() 4Tn97G7  
{ ///xx/weblogic60b2_win.exe ?7cT$/4  
try{ R|JBzdK+P  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ;Vlt4,s)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [`_-;/Gx2  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?a{es!  
fileFetch.start(); 9 6j*F,{  
} !UF(R^  
catch(Exception e){e.printStackTrace ();} tJ9-8ZT*  
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} 3.@I\p}  
:Lh`Q"a  
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public static void main(String[] args) p$!Q?&AV/  
{ P>[,,w  
new TestMethod(); c^W \0  
} 6sz:rv}  
} Gcp!"y=i  
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