http断点续传简单实现（java)

/* y7s.6i}7  
**SiteFileFetch.java ?`O Dt]s  
*/ 8M'6Kcr  
package NetFox; QWGFXy,=1  
import java.io.*; P%Ux-0&  
import java.net.*; Swz1RT  
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public class SiteFileFetch extends Thread { Qmh*Gh?v  
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SiteInfoBean siteInfoBean = null; //文件信息Bean YR`Mi.,Sfm  
long[] nStartPos; //开始位置 >KXT2+w  
long[] nEndPos; //结束位置 pf`li]j'V  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \:?H_^^d  
long nFileLength; //文件长度 .tb~f@xL  
boolean bFirst = true; //是否第一次取文件 VU*{E  
boolean bStop = false; //停止标志 ptuW}"F  
File tmpFile; //文件下载的临时信息 v+=_  
DataOutputStream output; //输出到文件的输出流 '17u W
q  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） .ODtduURe  
public SiteFileFetch(SiteInfoBean bean) throws IOException 0\U28zbMJw  
{ |E]YP~h  
siteInfoBean = bean; <`9:hPp0  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); -}juj;IVv  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Ve8`5  
if(tmpFile.exists ()) BWX&5""  
{ 8`qw1dF  
bFirst = false; d*,|?Ar*b  
read_nPos(); I>-jKSkwc  
} ?I 1@:?Qi  
else }%R6Su]y  
{ TCF[i
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nStartPos = new long[bean.getNSplitter()]; m x,X
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nEndPos = new long[bean.getNSplitter()]; "=f*Lk@[  
} a}c(#ZLs  
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} J= |[G'  
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public void run() "ej>1{3Y:=  
{ #G{T(0<F  
//获得文件长度 V`WfJ>{;Z  
//分割文件 cdIy[ 1  
//实例FileSplitterFetch `g :<$3}  
//启动FileSplitterFetch线程 f(n{7  
//等待子线程返回 kxUGd)S  
try{ "iZ-AG!C  
if(bFirst) "a"[B'  
{ ln=zGX.e  
nFileLength = getFileSize(); {U(h]'  
if(nFileLength == -1) w6"LHy[  
{ ?I@3`?'  
System.err.println("File Length is not known!"); WAdl@){  
} uN\9cQ  
else if(nFileLength == -2) @i)tQd!s  
{ Io"=X!k  
System.err.println("File is not access!"); )v-* WreS  
} -owfuS?i=  
else MK[spV  
{ wFd*6%  
for(int i=0;i<nStartPos.length;i++) 9vj:=,TNu  
{ l9L;Tjj  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ckP3[@Su {  
} sw@2 ?+  
for(int i=0;i<nEndPos.length-1;i++) 0'~b<>G%  
{ B]qh22Yib  
nEndPos = nStartPos[i+1]; i ('EBO  
} h?1pGz)[C  
nEndPos[nEndPos.length-1] = nFileLength; =}"hC`3e  
} <|`@K|N  
} q}1$OsM  
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//启动子线程 +8Px` v1L  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; '_&(Iwu  
for(int i=0;i<nStartPos.length;i++) jI
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{ uHIWbF<0oo  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), O``MUb b  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^/BE=$E\  
nStartPos,nEndPos,i); gdZVc9_  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dB,#`tc=,  
fileSplitterFetch.start(); [uY2Nh  
} ).boe& .  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;VH]TKkk  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $P@cS1sB  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", te''sydUS  
nEndPos = " + nFileLength); 2~U+PyeNz  
// fileSplitterFetch[nPos.length-1].start(); 0EB'!  
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//等待子线程结束 k
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//int count = 0; :&-}S>pC  
//是否结束while循环 T> 'Vaxo  
boolean breakWhile = false; V<pqc&f.  
2"'8x?.V  
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while(!bStop) i+Dgw  
{ %Tb|Yfyr C  
write_nPos(); )89jP088V  
Utility.sleep(500); [L(l++.z  
breakWhile = true; I`kp5lGD2  
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for(int i=0;i<nStartPos.length;i++) PPO<{  
{
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if(!fileSplitterFetch.bDownOver) oI~Qo*4eh  
{ N6[^62  
breakWhile = false; EXcjF  
break; z\Y^x9  
} E<SEFn  
} IR8&4qOs  
if(breakWhile) Y]K]]Ehp  
break; ^z;,deoGh  
,b(S=r  
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//count++; I{I [N &N  
//if(count>4) y;Ln ao7i  
// siteStop(); ;j>d"i36&  
} 5(7MQuRR  
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System.err.println("文件下载结束！"); 3a}`xCO5  
} )o</gt)  
catch(Exception e){e.printStackTrace ();} E}vO*ZZEw  
} s)8M? |[`I  
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//获得文件长度 7U`S9DDwq  
public long getFileSize() 2\\3<  
{ xt,L* B  
int nFileLength = -1; v@uaf=x-  
try{ G1_@! 4  
URL url = new URL(siteInfoBean.getSSiteURL()); 67\Ojl~(1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T$8~9qx  
httpConnection.setRequestProperty("User-Agent","NetFox"); `$SEkYdt  
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int responseCode=httpConnection.getResponseCode(); 7QiCZcb\  
if(responseCode>=400) j~*Z7iu  
{ q;zf|'&*7C  
processErrorCode(responseCode); ![]I%'s  
return -2; //-2 represent access is error "5JN
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} zHOE.V2Qo  
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String sHeader; iq uTT~  
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for(int i=1;;i++) >-@ U_p  
{ kTZx-7~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); m?VRX.>  
//Utility.log(in.readLine()); [&qbc#L  
sHeader=httpConnection.getHeaderFieldKey(i); 'c
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if(sHeader!=null) 7Jx-W|  
{ )
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if(sHeader.equals("Content-Length")) ](=wlq)  
{ bxdXZBn  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )ozcr^  
break; "c/s/$k//  
} uo4$rf7  
} Az< 9hk  
else \FoxKOTp  
break; xOL)Pjo/m  
} #xP!!.DF(  
} <@e+
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catch(IOException e){e.printStackTrace ();} p=~h|(M|  
catch(Exception e){e.printStackTrace ();} lke
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Utility.log(nFileLength); {y^|ET7  
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return nFileLength; ?ng14e  
} |#&V:GZp  
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//保存下载信息（文件指针位置） O*rmD<L$  
private void write_nPos() (H8C\%g:  
{ pYfV~Q^3  
try{ o3F|#op  
output = new DataOutputStream(new FileOutputStream(tmpFile)); [X }@Ct6  
output.writeInt(nStartPos.length); :6W^ S/pf  
for(int i=0;i<nStartPos.length;i++) JEsLF{  
{ `.>k)=F&  
// output.writeLong(nPos); W{A #]r l  
output.writeLong(fileSplitterFetch.nStartPos); "brRME3  
output.writeLong(fileSplitterFetch.nEndPos); w#xeua|*I#  
} B [+(r  
output.close(); ,!I?)hwOC  
} o9ctJf=qn  
catch(IOException e){e.printStackTrace ();} Ak6MPuBB-  
catch(Exception e){e.printStackTrace ();} ';b3Mm #  
} Uvh~B^6  
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;P;"F21^>  
//读取保存的下载信息（文件指针位置） h`5YA89  
private void read_nPos() VT% KN`l  
{ 3I"NI.>*  
try{ zJ;>.0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1yBt/
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int nCount = input.readInt(); Zk=*7?!!  
nStartPos = new long[nCount]; .hX0c"f
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nEndPos = new long[nCount]; Tm)GC_  
for(int i=0;i<nStartPos.length;i++) (*6m^  
{ jg [H}  
nStartPos = input.readLong(); #wenX$UTh3  
nEndPos = input.readLong(); D XV@DQ  
} !K3})& w  
input.close(); 0n:?sFY>  
} y=AsgJ  
catch(IOException e){e.printStackTrace ();} =&A!C"qK4[  
catch(Exception e){e.printStackTrace ();} 0#oBXu  
} u8YB)kG  
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private void processErrorCode(int nErrorCode) D~#Ei?aH  
{ Y[Q@WdE9  
System.err.println("Error Code : " + nErrorCode); U4>O\sU  
} }I]j&\  
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//停止文件下载 qib7Z]j  
public void siteStop() <B6[i*&  
{ ;%' b;+  
bStop = true; VeZey)Q  
for(int i=0;i<nStartPos.length;i++) Q%ruQ#  
fileSplitterFetch.splitterStop(); cjuZBFl  
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} Dv&>*0B  
} 25:Z;J>  
//负责部分文件的抓取 3bC+Mco  
**FileSplitterFetch.java LVnHt}  
*/ NYBe"/}GS  
package NetFox; h#i\iK&A
  
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import java.io.*; /aZE,IeEz  
import java.net.*; CSL#s^4T  
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public class FileSplitterFetch extends Thread { St@l]u9  
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String sURL; //File URL AoYaVlKG8  
long nStartPos; //File Snippet Start Position YOyp|%!  
long nEndPos; //File Snippet End Position #'@ilk/.  
int nThreadID; //Thread's ID 0DNU,u  
boolean bDownOver = false; //Downing is over 9Bz0MUbrLl  
boolean bStop = false; //Stop identical Z%}4bJ  
FileAccessI fileAccessI = null; //File Access interface n`(~OO  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException fc@'9-pt  
{ i9rS6<
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this.sURL = sURL; 0VN7/=n|  
this.nStartPos = nStart; 6;o3sf@Tf  
this.nEndPos = nEnd; X\Y}oa."A  
nThreadID = id; !\-WEQrp\  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 hQRL,?  
} _;hf<|c  
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public void run() h[kU<mU"T  
{ 3J~0O2  
while(nStartPos < nEndPos && !bStop) rn8c
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{ O0T/#<Cn!  
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try{ v4rW2F:X  
URL url = new URL(sURL); Fv8f+)k)Z~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0K`[,
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httpConnection.setRequestProperty("User-Agent","NetFox"); Z^yNLF*&V  
String sProperty = "bytes="+nStartPos+"-"; !R'g59g  
httpConnection.setRequestProperty("RANGE",sProperty); $TG=w  
Utility.log(sProperty); ?A?F.n`  
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InputStream input = httpConnection.getInputStream(); vDFGd-S  
//logResponseHead(httpConnection); eF~dQ4RZ  
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byte[] b = new byte[1024]; D`[Khsf  
int nRead; aUc|V{Jp  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) -TO\'^][X  
{ u0QzLi,  
nStartPos += fileAccessI.write(b,0,nRead); q_V0+
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//if(nThreadID == 1) u JY)4T  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >6<q8{*  
} .fAv*pUzU  
"ZrOrdlg+A  
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Utility.log("Thread " + nThreadID + " is over!"); 15U(={  
bDownOver = true; "%qzj93>  
//nPos = fileAccessI.write (b,0,nRead); t `kui.  
} 1yQejw  
catch(Exception e){e.printStackTrace ();} _n;;][
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} kD5!}+y  
} 3djC;*,9,  
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//打印回应的头信息 x3 >  
public void logResponseHead(HttpURLConnection con) 3
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{ rG}\Zjn{  
for(int i=1;;i++) 99xEm  
{ nUS| sh  
String header=con.getHeaderFieldKey(i); S35~Cp  
if(header!=null) _ :Ag?2  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); En{`@JsM  
Utility.log(header+" : "+con.getHeaderField(header)); }e2VY  
else sEMQ  
break; 2*w0t:Yxe  
} ]:>,A@7  
} qz?mh4Oh  
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public void splitterStop() 0k)rc$eDF+  
{ }}v9 `F  
bStop = true; v6.t{6zYgY  
} AIMSX]m  
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} h2ytS^  
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/* pRkP~ZISU  
**FileAccess.java {9UEq0  
*//文件访问(定位，写) .<@8gNm3  
package NetFox; `]Q:-h  
import java.io.*; vz.>~HBP  
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public class FileAccessI implements Serializable{ S<'[%ihx  
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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 93Co}@Y;Y+  
RandomAccessFile oSavedFile; S$QG.K:<!  
long nPos; 94B\5I}  
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public FileAccessI() throws IOException `BlI@6th  
{ g+J-Zg6  
this("",0); bv&;R  
} B95B|tU>.  
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public FileAccessI(String sName,long nPos) throws IOException 4$P0:  
{ "'D=,*  
oSavedFile = new RandomAccessFile(sName,"rw"); /`mks1:pK  
this.nPos = nPos; #Y$hNQQ$F  
oSavedFile.seek(nPos); \otWd  
} Oil?JI Hq  
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public synchronized int write(byte[] b,int nStart,int nLen) v%q0OX>9X"  
{ )ubiB^g'm  
int n = -1; Za1QC;7  
try{ :Of^xj>
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oSavedFile.write(b,nStart,nLen); DQr Y*nH  
n = nLen; =>_\fNy  
} oz,e/v8~  
catch(IOException e) #w' k
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{ b:TLV`>/&  
e.printStackTrace (); PpAu!2lt9  
} !wNr3LG  
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return n; 2+e}*&iQpp  
} MB]<Dyj,  
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} `~By)?cT_>  
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/* gcl5jB5)>  
**SiteInfoBean.java OWg(#pZk  
*/ 4bYK}oS  
package NetFox; pC@{DW;V6R  
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public class SiteInfoBean { ^f4s"T  
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private String sSiteURL; //Site's URL ]H+8rY%+  
private String sFilePath; //Saved File's Path lww!-(<ww  
private String sFileName; //Saved File's Name HMh"}I2n  
private int nSplitter; //Count of Splited Downloading File /}b03  
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public SiteInfoBean() >I-RGW'A  
{//nSplitter的缺省值为5 l3ko?k  
//default value of nSplitter is 5 CYY=R'1:G{  
this("","","",5); 4NheWM6  
} &m)6J'q3k  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) nxnv,AZG  
{ eg;~zv  
sSiteURL= sURL; O;:mCt _H  
sFilePath = sPath; JfLqtXF[&"  
sFileName = sName; 4%>$-($  
this.nSplitter = nSpiltter; R;uvkg[o  
#S!)JM|4wk  
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} X86O lP)eX  
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public String getSSiteURL() L*xhGoC=  
{ D#cyOrzy  
return sSiteURL;  mHdA2  
} h-q3U%R4}@  
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public void setSSiteURL(String value) ^c"jH'#.L  
{ 6F!+T=  
sSiteURL = value; .sh
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} s~ a"4~f  
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public String getSFilePath() Lb:g4A"  
{ #+Ir>GU  
return sFilePath; YxYH2*q@  
} %?0:vn  
!;q&NHco  
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public void setSFilePath(String value) +\d56j+D  
{ Gw/Pk4R  
sFilePath = value; )WNzWUfn=z  
} cOmw?kA*G  
2b}t,&bv?  
a!6{:8Zi0  
public String getSFileName() GZN ^k+w  
{ (y=C_wvqZ  
return sFileName; EH+"~-v)ae  
} I667Gz$j5  
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public void setSFileName(String value) vOn`/5-  
{ U6glp@s  
sFileName = value; DU0zez I9  
} o |{5M|nD  
d[@X%  
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public int getNSplitter() D=q:*x  
{ %<\vGqsM  
return nSplitter; >N^Jj:~l  
} fx41,0;gZq  
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public void setNSplitter(int nCount) {2O1"|s ,  
{ g!g#]9j  
nSplitter = nCount; f%is~e~wc  
} pNG:0  
} ,Xu-@br{  
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/* |kyX3~  
**Utility.java Rvqq.I8aC  
*/ ,;EIh}  
package NetFox; LC,F <>w1  
:(/~:^!  
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public class Utility { FvaUsOy
"  
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public Utility() F%@A6'c  
{ +%+tr*04O  
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} zIqU,n|]s  
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//线程睡眠 T;Lka
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public static void sleep(int nSecond) Y@;CF  
{ rJ`!:f  
try{ M1k{t%M+S  
Thread.sleep(nSecond); 3lf=b~Zi
)  
} R[zpD%CI  
catch(Exception e) 0eT(J7[ <  
{ 8o3E0k1  
e.printStackTrace (); 3U<cWl@  
} bBiE  
} |)IlMG  
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//日志 w;%.2VJ  
public static void log(String sMsg) T-'OwCB1q  
{ n4O]8C'lW9  
System.err.println(sMsg); b:U$x20n$  
} ]3D0R;  
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:">!r.Q  
public static void log(int sMsg) YX!{P=Ua  
{ ts,ZvY]  
System.err.println(sMsg); r)Ma3FL0;  
} @D]5civm_  
} xipU8'ac/  
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/* U'k*_g
 
**TestMethod.java @bi}W`  
*/ Y[ j6u\y  
package NetFox; )%`c_FL@N=  
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public class TestMethod { l3{-z4mw  
)\1@V+!E%  
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public TestMethod() 5-FQMXgThc  
{ ///xx/weblogic60b2_win.exe 8f_l}k$Eg  
try{ Mc?Qx  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); h8x MI  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6,^>mNm  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 7!evm;A  
fileFetch.start(); gI&#o@Pm  
} fZ6MSAh  
catch(Exception e){e.printStackTrace ();} fnpYT:%fG  
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} RaO-H  
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public static void main(String[] args) B*eC3ok3z  
{ kS%Ydy#:'  
new TestMethod(); 48J@CvU  
} aH yx_B  
} eJrQ\>z]V&  
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