http断点续传简单实现（java)

/* !9NAm?Fw  
**SiteFileFetch.java -OxHQ  
*/ >i<-rO>kN  
package NetFox; 8&bj7w,K  
import java.io.*; =uTV\)  
import java.net.*; ?i"FdpW  
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public class SiteFileFetch extends Thread { `Ea3z~<7M  
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SiteInfoBean siteInfoBean = null; //文件信息Bean RCr:2 Iz  
long[] nStartPos; //开始位置 m~A/.t%=  
long[] nEndPos; //结束位置 2}-W@R  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 c#Bde-dh  
long nFileLength; //文件长度 V"XN(Fd^  
boolean bFirst = true; //是否第一次取文件 WDq3K/7\  
boolean bStop = false; //停止标志 JZ [&:  
File tmpFile; //文件下载的临时信息 0Og =H79<  
DataOutputStream output; //输出到文件的输出流 w93,N+es6  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） th{h)( +H  
public SiteFileFetch(SiteInfoBean bean) throws IOException -u{:39y{n  
{ (XQG"G%U6W  
siteInfoBean = bean; ;a"Ukh  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ewY X\  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); "fdG5|NJe  
if(tmpFile.exists ()) <jF<_j  
{ #XZ?,neY  
bFirst = false; J$oJ  
read_nPos(); (;N_lF0  
} a/1{tDA  
else tP9}:gu  
{ pH%K4bV)8  
nStartPos = new long[bean.getNSplitter()]; U\N`[k.F  
nEndPos = new long[bean.getNSplitter()]; 6*E7}  
} `Cc<K8s8  
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} YL]x>7T~4t  
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public void run() ZHT.+X:_  
{ iiu\_ a=0b  
//获得文件长度 ?AEpg.9R-  
//分割文件 fqi584  
//实例FileSplitterFetch XX =A1#H  
//启动FileSplitterFetch线程 kciH  
//等待子线程返回 }.#C9<"}  
try{ WE3l*7<@  
if(bFirst) "2)T=vHi#  
{ d%<Uh(+:  
nFileLength = getFileSize();
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if(nFileLength == -1) F~m tE8B:  
{ 5%9
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System.err.println("File Length is not known!"); Wl1%BN0>  
} B=f{`rM)~W  
else if(nFileLength == -2) /<@oUv  
{ GB0] |z5  
System.err.println("File is not access!"); }Vt5].TA  
} 2`; 0y M  
else qYE-z(i  
{ +f+\uObi:  
for(int i=0;i<nStartPos.length;i++) PpbW+}aCF  
{ RtSk;U1  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); -" DI,o  
} {W0@lMrD  
for(int i=0;i<nEndPos.length-1;i++) | #,b1|af  
{ JI.ad_IR
 
nEndPos = nStartPos[i+1]; ,+2ytN*  
} 2D "mq~V  
nEndPos[nEndPos.length-1] = nFileLength; %;gD_H4mm  
} d
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} h5F1mr1Sa  
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P"
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//启动子线程 =!7yX;|  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Q?vGg{>  
for(int i=0;i<nStartPos.length;i++) :
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{ ,#<"VU2bC  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $"sf%{~  
nStartPos,nEndPos,i); T1Xm^{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); WO]dWO6Mm  
fileSplitterFetch.start(); " 4s,a  
} FX\ -Y$K  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *8Gx_$t&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &}rh+z  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -BR&b2  
nEndPos = " + nFileLength); I9_tD@s"(  
// fileSplitterFetch[nPos.length-1].start(); aVd{XVE  
 F`f#gpQ  
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//等待子线程结束 \07 s'W U  
//int count = 0; NFsMc0{  
//是否结束while循环 U1B5
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boolean breakWhile = false; $$AKz\  
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while(!bStop) }*;Hhbox  
{ C)Mh  
write_nPos(); jRzR`>5  
Utility.sleep(500); Ot5 $~o  
breakWhile = true; Jo_h?{"L{  
^BW V6  
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for(int i=0;i<nStartPos.length;i++) 8z\WyDz  
{ db4Ol=  
if(!fileSplitterFetch.bDownOver) ,0;E_i7  
{ Qr$uFh/y  
breakWhile = false; BHqJ~2&FDW  
break; Rax}r  
} )9==6p  
} $GPenQ~},  
if(breakWhile) $U3s:VQ'  
break; IKH#[jW'IB  
>i-cR4=LL{  
mbU[fHyV  
//count++; c(i-~_  
//if(count>4) "3W!p+W  
// siteStop(); Z'hW;^e%_z  
} rQ LNo,  
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System.err.println("文件下载结束！"); ^3F[^#"  
} .^fq$7Y}7  
catch(Exception e){e.printStackTrace ();} +kmPQdO;*/  
} RV.*_FG  
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//获得文件长度 Ay22-/C|@  
public long getFileSize() JIQS'
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{ 8!'#B^  
int nFileLength = -1; ~W_m<#K(  
try{ ;a[56W  
URL url = new URL(siteInfoBean.getSSiteURL()); eOE7A'X  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); z ~T[%RjO  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7_?:R2]n  
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int responseCode=httpConnection.getResponseCode(); ZjF$zVk  
if(responseCode>=400) 25NZIal<  
{ =(3Qbb1i  
processErrorCode(responseCode); w$u=_  
return -2; //-2 represent access is error 1.4]T, `  
} 5M;fh)fT  
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String sHeader; '(7]jug  
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j*Ta?'*  
for(int i=1;;i++) E;fYL]j/oZ  
{ DvKM[z3j  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ?kI-o0@O.  
//Utility.log(in.readLine()); \f}S Hh  
sHeader=httpConnection.getHeaderFieldKey(i); fILINW{Yk)  
if(sHeader!=null) @kenv3[Lc  
{ .9#4qoM'  
if(sHeader.equals("Content-Length")) 8$io^n\i  
{ Ia=wf"JS)  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); rbHrG<+7zO  
break; Xp[[ xV|  
} ; =ai]AYW  
} `(vgBz`e[  
else Py^F},?J  
break; WZ"NG|  
} 7[rn ,8@  
} KdHR.;*  
catch(IOException e){e.printStackTrace ();} AU)"L_ i}  
catch(Exception e){e.printStackTrace ();} Z3<>Z\6D  
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Utility.log(nFileLength); +AhR7R!
 
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return nFileLength; ,%w_E[2  
} T^B&GgW  
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M=H
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//保存下载信息（文件指针位置） .+t{o[  
private void write_nPos() Oh9wBV  
{ eS8tsI  
try{ $qYtN`b,  
output = new DataOutputStream(new FileOutputStream(tmpFile)); RIJ+]uir4  
output.writeInt(nStartPos.length); C'4u+raq  
for(int i=0;i<nStartPos.length;i++) .;ml[DXH  
{ "#z4  
// output.writeLong(nPos); Po'yr]pr  
output.writeLong(fileSplitterFetch.nStartPos); Z#BwJHh  
output.writeLong(fileSplitterFetch.nEndPos); 7}(wEC  
} JP)/ O!  
output.close(); "%dWBvuO  
} 5gARGA  
catch(IOException e){e.printStackTrace ();} tQ_;UQlX  
catch(Exception e){e.printStackTrace ();} =B4U~|k  
} U>7"BpC  
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//读取保存的下载信息（文件指针位置） EKZ40z`  
private void read_nPos() j
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{ IE.JIi^w  
try{ G,9osTt/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <&\HXAOd  
int nCount = input.readInt(); ?6+GE_VZ  
nStartPos = new long[nCount]; #~*fZ|sq+3  
nEndPos = new long[nCount]; 8fFURk  
for(int i=0;i<nStartPos.length;i++) ${0+LhST  
{ /1:`?% ,2  
nStartPos = input.readLong(); ]^$&Ejpe#  
nEndPos = input.readLong(); $J"}7+  
} 7\@[e, ^9  
input.close(); ^$f}s,09  
} 6f,#O8]#5  
catch(IOException e){e.printStackTrace ();} |UZPn>F~  
catch(Exception e){e.printStackTrace ();} g#ubxC7t<  
} 34_:.QK-  
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private void processErrorCode(int nErrorCode) jv<BGr=4;  
{ TV\21  
System.err.println("Error Code : " + nErrorCode); w^e<p~i!^E  
} 9iGUE  
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//停止文件下载 5VdF^.:u  
public void siteStop() }eb}oK  
{ "f/lm 2<  
bStop = true; XBe!9/'k>  
for(int i=0;i<nStartPos.length;i++) ^+tAgK2   
fileSplitterFetch.splitterStop(); L^uO.eI"m  
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} dPgN*Bdv  
} /=&HunaxI  
//负责部分文件的抓取 C-'n4AY^  
**FileSplitterFetch.java Cfqgu;m  
*/ F+ qRC_C>O  
package NetFox; :S'P lH  
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import java.io.*; aal5d_Y  
import java.net.*; 4%>iIPXi.(  
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public class FileSplitterFetch extends Thread { MLg+ 9y  
q66!xhp;?  
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String sURL; //File URL vpu20?E>5z  
long nStartPos; //File Snippet Start Position s)X'PJ0&Bs  
long nEndPos; //File Snippet End Position }qU(G3  
int nThreadID; //Thread's ID 9nF;$HB  
boolean bDownOver = false; //Downing is over #AHX{<  
boolean bStop = false; //Stop identical 'k[d&sR  
FileAccessI fileAccessI = null; //File Access interface :H($|$\h  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException
7`-fN|  
{ 
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this.sURL = sURL; Ca}T)]//  
this.nStartPos = nStart;  JwEQR  
this.nEndPos = nEnd; OSACH0h  
nThreadID = id; 1KwUp0%&  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ajB4Lj,:r  
} pIcvsd  
/J{ e_a  
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public void run() <NRW^#g<x  
{ /4x3dwXW@  
while(nStartPos < nEndPos && !bStop) u.W}{-+kp  
{ anLSD/'4W  
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try{ pxC:VJ;  
URL url = new URL(sURL); ^f][;>c  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); JBzRL"|  
httpConnection.setRequestProperty("User-Agent","NetFox"); cTlitf9  
String sProperty = "bytes="+nStartPos+"-"; v&}+ps_W  
httpConnection.setRequestProperty("RANGE",sProperty); ?+6w8j%\  
Utility.log(sProperty); 2e~ud9,  
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InputStream input = httpConnection.getInputStream(); bEx8dc`Q  
//logResponseHead(httpConnection); w]2tb
  
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byte[] b = new byte[1024]; E1'| ;}/  
int nRead; g+CTF67  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) B_Qi  
{ U9N1)3/u  
nStartPos += fileAccessI.write(b,0,nRead); @|A wT  
//if(nThreadID == 1) v(Vm:oK,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C8^=7HEB  
} eAkC-Fm  
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#L,>)XkjS  
Utility.log("Thread " + nThreadID + " is over!"); #p<1@,  
bDownOver = true; T
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//nPos = fileAccessI.write (b,0,nRead); UD.&p'^ /{  
} "v%|&@  
catch(Exception e){e.printStackTrace ();} =lyP &u  
} %~z/,[wk  
} pS [nKcyj  
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//打印回应的头信息 I,rs&m?/m  
public void logResponseHead(HttpURLConnection con) QY$Z,#V)  
{ W PDL$y  
for(int i=1;;i++) (t^&L  
{ Z.!tp  
String header=con.getHeaderFieldKey(i); c5KJ_Nfi  
if(header!=null) a?^xEye  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); WnATgY t  
Utility.log(header+" : "+con.getHeaderField(header)); \a\J0&Z  
else %Fb4   
break; ez2rCpA  
} :Fvd?[  
} 2!UNFv#=$  
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public void splitterStop() fi/[(RBG  
{ 627
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bStop = true; naQ0TN,  
} L%3m_'6QP  
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$ N7J:Q  
} >'qkW$-95  
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/* #5Zf6w  
**FileAccess.java GpW
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*//文件访问(定位，写) |l*#pN&L  
package NetFox; )2 Omsh  
import java.io.*; uTSTBI4t  
^CZ)!3qd1  
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public class FileAccessI implements Serializable{ kX\\t.nH  
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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
 :RYh@.  
RandomAccessFile oSavedFile; ;OE=;\  
long nPos; `2 vv8cg^  
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public FileAccessI() throws IOException d#?.G3YmK  
{ ka3(sctZ5  
this("",0); 'CTvKW  
} L`fDc  
.x 1& 
  
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public FileAccessI(String sName,long nPos) throws IOException Rh:@@4<  
{ eyx;8v cM  
oSavedFile = new RandomAccessFile(sName,"rw"); ~|LlT^C  
this.nPos = nPos; 5<?O S &B  
oSavedFile.seek(nPos); Z+zx*(X  
} "IK QFt'  
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public synchronized int write(byte[] b,int nStart,int nLen) ^>g7Kg"0  
{ w(sD}YA)  
int n = -1; dkz79G}e  
try{ ' 9K4A'2[  
oSavedFile.write(b,nStart,nLen); }d,iA FG  
n = nLen; FfDe&/,/  
} 7TTU&7l~  
catch(IOException e) R'#[
}s  
{ yJt0KUw@!  
e.printStackTrace (); '
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} d+5KHfkK  
^

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return n; W!$aK)]4u  
} [
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} 7=YjY)6r^  
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/* '.n0[2>  
**SiteInfoBean.java |Rh%wJ  
*/ `@8QQB  
package NetFox; AE:IXP|c  
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public class SiteInfoBean { PD@]2lY(  
!n<vN@V*3d  
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private String sSiteURL; //Site's URL 1^G*)Qn5Df  
private String sFilePath; //Saved File's Path wnaT~r@U'  
private String sFileName; //Saved File's Name [4V{~`sF  
private int nSplitter; //Count of Splited Downloading File {uO=Wkp~7  
{q9[0-LyJ  
3BBw:)V  
public SiteInfoBean() icq!^5BzL  
{//nSplitter的缺省值为5 Cr?|bDv}o  
//default value of nSplitter is 5 KrcL*j&^  
this("","","",5); b?6-lYE>L  
} +|#lUXC  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) FLT4:B7  
{ @dl{.
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sSiteURL= sURL; U)Cv_qe  
sFilePath = sPath; ),9^hJ1+@  
sFileName = sName; (vX+ Yw  
this.nSplitter = nSpiltter; ZT*RD2,  
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lTl-<
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} HAq  
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public String getSSiteURL() aS ]bTYJ'  
{ 2g>4fZ  
return sSiteURL; A*;I}F  
} %,HuG-L  
8ZYF%  
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public void setSSiteURL(String value) [PVem  
{ HYd&.*41rE  
sSiteURL = value; }$6;g-|HX  
} 99GzhX_  
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6Vr:?TI7  
public String getSFilePath() g^ @9SU  
{ ,,U8X [A  
return sFilePath; ]: VR3e"H  
} uVnbOqR<X  
1y\-Iz
^  
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public void setSFilePath(String value) t0^chlJP$  
{ FU;b8{Y  
sFilePath = value; 6V[ce4a%  
} 0l.\KF  
^0 zWiX  
,hMdxZJd  
public String getSFileName() ^oykimYI-  
{ 33O O
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return sFileName; /UwB6s(  
} <=1nr@L  
75>)1H)Xm  
],!7S"{97  
public void setSFileName(String value) rsr}%J  
{ =g]Ln)jc  
sFileName = value; l"T{!Oq  
} G54,`uz2  
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#YABbwH  
public int getNSplitter() WUEjWJA-MB  
{ .ty^k@J|]  
return nSplitter; pwu8LQ3b{O  
} oRp;9   
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public void setNSplitter(int nCount) 5eP0W#  
{ ,McwPHEMB  
nSplitter = nCount; )MV`(/BC*  
} IJ#G/<ZJZ  
}
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W*S!}ZT`  
/* <B3v4f  
**Utility.java <Z0N)0|  
*/ |I0O|Zdv  
package NetFox; E0SP  
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public class Utility { 9f wFSJx  
#z(
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public Utility() Ts~MkO  
{ {}Q A#:V  
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} C>A*L4c]F  
0E
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//线程睡眠 lZ\8$,B)  
public static void sleep(int nSecond) ~9tPT0^+  
{ A,WZ}v}_  
try{ |=xK-;qs  
Thread.sleep(nSecond); vvsQf
%  
} PX5K-|R  
catch(Exception e) ec$kcD!  
{ h_SDW %($  
e.printStackTrace (); uyp|Xh,  
} Zn-F!Lsv  
} cTq
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qMHI-h_A  
//日志 bPe|/wp  
public static void log(String sMsg) gM5`UH|  
{ :X66[V&eH  
System.err.println(sMsg); R cz;|h8  
} l9zkx'xt.-  
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+O2z&a;q  
public static void log(int sMsg) U|NVDuo{{x  
{ >~D-\,d|f  
System.err.println(sMsg); `Tt;)D  
} j$he5^GC  
} ~zcHpxO^W  
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/* 7M#irCX  
**TestMethod.java 5Y#W$Fx($R  
*/ k3w(KH@  
package NetFox; LzS)WjEN  
l-} );zH74  
)6k([u%;B  
public class TestMethod { +@j@#~=K  
)[c@5zy~*  
{]F};_  
public TestMethod() SGp}(j>  
{ ///xx/weblogic60b2_win.exe 1 po.Cmx  
try{ o~(/Twxam  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); lV*dQwa?i  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); #7Pnw.s3zz  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \d,wcL  
fileFetch.start(); 9?IvSv}z  
} 9CxFj)#5F  
catch(Exception e){e.printStackTrace ();} $YNWT\
FE  
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} -fB;pS,  
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public static void main(String[] args) ;4!,
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{ GjfPba4>  
new TestMethod(); =u.jZ*u]WT  
} z :q9~  
} GgNqci,  
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