http断点续传简单实现（java)

/*  }D!o=Mg^  
**SiteFileFetch.java WdbHT|.Aj  
*/ [f]:hJi  
package NetFox; !j9(%,PR  
import java.io.*; J$S*QCo  
import java.net.*; Qa"4^s  
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public class SiteFileFetch extends Thread { MTn}]blH  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 72= 4#  
long[] nStartPos; //开始位置 %Ybr5$_  
long[] nEndPos; //结束位置 ceae~  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 n]3Z~HoZ  
long nFileLength; //文件长度 <m%ZDOMa  
boolean bFirst = true; //是否第一次取文件 K"Gea`I  
boolean bStop = false; //停止标志 a#&\65D  
File tmpFile; //文件下载的临时信息 $v=(`
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DataOutputStream output; //输出到文件的输出流 }s.\B 
 
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） A%~t[
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public SiteFileFetch(SiteInfoBean bean) throws IOException "P$')uwE  
{ va!fJ  
siteInfoBean = bean; fH%C&xj'&  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,W>-MPJn[8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); G~/*!?&z  
if(tmpFile.exists ()) 1{G@'#(  
{  k.\4<}  
bFirst = false; 4Td)1~zc3  
read_nPos(); )#,a'~w  
} ,t39~w  
else Sb`SJ):x  
{ fdgjTX  
nStartPos = new long[bean.getNSplitter()]; BipD8`a  
nEndPos = new long[bean.getNSplitter()]; X&A2:A 6\+  
} F`.W 9H3
 
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} >bg{  
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public void run() hPt=j{aJ%<  
{ ^CB@4$!   
//获得文件长度 PrF('PH7i  
//分割文件 3lg
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//实例FileSplitterFetch #_zj5B38E  
//启动FileSplitterFetch线程 jIWX6  
//等待子线程返回 T;3B_lu]  
try{ 0&c<1;  
if(bFirst) Rd|^C$6  
{ J$&2GAi  
nFileLength = getFileSize(); rWJKK  
if(nFileLength == -1) 3vEwui-5  
{ +xNq8yS  
System.err.println("File Length is not known!"); I<S*"[nV  
} u89Q2\z~"M  
else if(nFileLength == -2) QG09=GQ  
{
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System.err.println("File is not access!"); ~jJe|zg>  
} TIno"tc3  
else gKRlXVS  
{ !iUT Re  
for(int i=0;i<nStartPos.length;i++) TtgsM}Fm  
{ W&2r{kCsQ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); MgHO WoF  
} o>I,$=  
for(int i=0;i<nEndPos.length-1;i++) \$,8aRT>#U  
{ ,?!MVN-  
nEndPos = nStartPos[i+1]; i$H9~tPs  
} 'acCnn'  
nEndPos[nEndPos.length-1] = nFileLength; TZarI-A  
} + ,rl\|J%  
} 'fY29Xr^  
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jr^btVOI#\  
//启动子线程 ty8E;['  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; K%;=i2:  
for(int i=0;i<nStartPos.length;i++) AdRK)L  
{ `Nv7c{M^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), KnUVR!H|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),
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nStartPos,nEndPos,i); "f-HOd\=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); HcHwvf6y  
fileSplitterFetch.start(); vP,$S^7$  
} H2CpZK'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Q=^TKsu  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", O66b^*=N}x  
nEndPos = " + nFileLength); n^/)T3mz{  
// fileSplitterFetch[nPos.length-1].start(); %5j*e  
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:%IB34e  
//等待子线程结束 ^-(DokdBn  
//int count = 0; }zrapL"9X  
//是否结束while循环 `|4k>5k  
boolean breakWhile = false; a!,X@5  
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while(!bStop) Oki{)Ssy  
{ "fu@2y4^  
write_nPos(); Gl9,!"A  
Utility.sleep(500); I~,bZA  
breakWhile = true; &PFK0tY  
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for(int i=0;i<nStartPos.length;i++) !'a <Dw5  
{ @R;&PR#5  
if(!fileSplitterFetch.bDownOver) i\kDb=  
{ K8h\T4  
breakWhile = false; W?du ]  
break; JG{`tTu  
} [$Jsel<T=  
} 0m4'm<2m  
if(breakWhile) FPu$Nd&\  
break; Tj!rAMQk  
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//count++; }w{E<C(M  
//if(count>4) x}#N?d
  
// siteStop(); [x -<O:r=P  
} {N@Pk[!  
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System.err.println("文件下载结束！"); 1tlqw  
} kT:?1w'  
catch(Exception e){e.printStackTrace ();} Tb{RQ?Nw'  
} 7hT@,|(j  
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//获得文件长度 AL|3_+G  
public long getFileSize() ,?w
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{ 7nZ3u_~  
int nFileLength = -1; imyfki $B  
try{  Au*1-  
URL url = new URL(siteInfoBean.getSSiteURL()); c~!ETwpHQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V9wL3*  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,Uy;jk  
rnBp2'EM  
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int responseCode=httpConnection.getResponseCode(); D0h6j0r5  
if(responseCode>=400) @QF;m  
{ qpq(<  
processErrorCode(responseCode); t"YN:y8-  
return -2; //-2 represent access is error \!IEZ  
} 9G4os!x)  
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=)J<R;  
String sHeader; `tl-] ^Y2  
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for(int i=1;;i++) $ SZIJe"K  
{ So4#n7  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); zO0K*s.yK  
//Utility.log(in.readLine()); c,#Nd@  
sHeader=httpConnection.getHeaderFieldKey(i); @[{5{ y  
if(sHeader!=null) Ti>}To}B5  
{ }$s QmRR  
if(sHeader.equals("Content-Length")) :bXTV?#0  
{ t|*UlTLm  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); LdnTdh?  
break; @
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} TW=N+ye^1(  
} {,= hIXo>  
else %
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break; ypx`!2Q$  
} A>\3FeU>UC  
} >S%}HSPKq  
catch(IOException e){e.printStackTrace ();} fyxc4-D  
catch(Exception e){e.printStackTrace ();} 3;R`_#t+  
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Utility.log(nFileLength); YB(8 T"  
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return nFileLength; Y]i:$X]C?X  
} c)c_Qv  
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//保存下载信息（文件指针位置） OK2\2&G  
private void write_nPos() hPUZ{#;n  
{ 1[\I9dv2  
try{ 61*b|.sl'#  
output = new DataOutputStream(new FileOutputStream(tmpFile)); P@Vs\wAT  
output.writeInt(nStartPos.length); C#RueDa.  
for(int i=0;i<nStartPos.length;i++) _B\87e  
{ U\>k>|Jr{  
// output.writeLong(nPos); {vur9L  
output.writeLong(fileSplitterFetch.nStartPos); rym*W\AWx  
output.writeLong(fileSplitterFetch.nEndPos); #r]GnC,  
} ACF_;4%&  
output.close(); .:tR*Kst`7  
}  1 K]  
catch(IOException e){e.printStackTrace ();} lo36b zbT  
catch(Exception e){e.printStackTrace ();} !"'@c  
} +y][s{A  
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//读取保存的下载信息（文件指针位置） !ED,'d%J  
private void read_nPos() 5xa!L@)`wF  
{ S4OOm[8  
try{ 1"T&B0G3l  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); B0^:nYko  
int nCount = input.readInt(); w<I
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nStartPos = new long[nCount]; ?S.LGc  
nEndPos = new long[nCount]; NU[Wj uLG  
for(int i=0;i<nStartPos.length;i++) >uE<-klv  
{ ~L.5;8a3Pe  
nStartPos = input.readLong(); {(h!JeQ  
nEndPos = input.readLong(); 7*4i0{]  
} <lWBhrz  
input.close(); iu{QHjZK(  
} lLEEre  
catch(IOException e){e.printStackTrace ();} {wD "|K  
catch(Exception e){e.printStackTrace ();} F0'8n6zj  
} Hq,znRz~`  
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private void processErrorCode(int nErrorCode) %t$)sg]  
{ d%oHcn  
System.err.println("Error Code : " + nErrorCode); (>dL  
} uFaT~ 4  
%@%~<U)W  
;!EEzR.  
//停止文件下载 ppO!v?  
public void siteStop() p&HkR^.S  
{ E%$[*jZ  
bStop = true; e{.P2rnh  
for(int i=0;i<nStartPos.length;i++) ~~#/jULbV  
fileSplitterFetch.splitterStop(); > Qh#pn*  
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} V
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} &cf_?4  
//负责部分文件的抓取 )(yKm/50  
**FileSplitterFetch.java ]Yf8  
*/ pH0MVu(W  
package NetFox; v&`n}lS  
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import java.io.*; Dj w#{WR  
import java.net.*; 5=;'LW
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public class FileSplitterFetch extends Thread { (KR.dxzjf  
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String sURL; //File URL '@#l/9
 
long nStartPos; //File Snippet Start Position ={~A} X01  
long nEndPos; //File Snippet End Position Ky{C;7X  
int nThreadID; //Thread's ID }$:ha>  
boolean bDownOver = false; //Downing is over Rz33_ qA  
boolean bStop = false; //Stop identical Fh.ZsPn,m  
FileAccessI fileAccessI = null; //File Access interface (-{.T  
6Q`7>l.|?  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _61tE  
{ [V;Q#r&+  
this.sURL = sURL; 0|?DA12Z  
this.nStartPos = nStart; Chtls;Ph[  
this.nEndPos = nEnd; ET|4a(x  
nThreadID = id; NaeG)u#+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 S?Uvt?  
} jDW$}^ 6  
{!"lHM%  
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public void run() S#|5&SR  
{ {|tMN,Z  
while(nStartPos < nEndPos && !bStop) wE_#b\$=b  
{ 9bD ER  
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try{ AaJz3oncJ  
URL url = new URL(sURL); 1@`mpm#Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $PTl{  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0f,Ii_k bT  
String sProperty = "bytes="+nStartPos+"-"; <:~'s]`zf  
httpConnection.setRequestProperty("RANGE",sProperty); d'p@[1/  
Utility.log(sProperty); \p!mX|  
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InputStream input = httpConnection.getInputStream(); 3yM!BTlX  
//logResponseHead(httpConnection); -)E6{  
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byte[] b = new byte[1024]; Mj:=$}rs^  
int nRead; {c=H#- A  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)
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{ >\ PNKpn{  
nStartPos += fileAccessI.write(b,0,nRead); n}
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//if(nThreadID == 1) N#
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;3N>m|?D=  
} efm#:>H  
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/Y*6mQ:  
Utility.log("Thread " + nThreadID + " is over!"); Evq^c5n>{  
bDownOver = true; Vxim$'x!  
//nPos = fileAccessI.write (b,0,nRead); q6V\n:hKV  
} q]z%<`.9*  
catch(Exception e){e.printStackTrace ();} 9'h4QF+Y  
} *AI
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} s#V:! 7  
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//打印回应的头信息 |FZIUS{]  
public void logResponseHead(HttpURLConnection con) FQikFy(YY  
{ _,E! <  
for(int i=1;;i++) H,U qU3b3  
{ sTFRu  
String header=con.getHeaderFieldKey(i); )Jd{WC.  
if(header!=null) m#t  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); (J\Qo9Il  
Utility.log(header+" : "+con.getHeaderField(header)); Kv6#WN~  
else +FtL_7[v  
break; Pqv9>N|  
} ?1/wl;=fm  
} PD@@4@^
 
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public void splitterStop() W$?Bsz)  
{ !$.h[z^  
bStop = true; n ,CMGe^:  
} ~(d#T|ez  
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} ~bSjZ1`  
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/* ^[-3qi  
**FileAccess.java \d"M&-O  
*//文件访问(定位，写) <!.Q
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package NetFox; 5SmgE2}  
import java.io.*; 1N\-Ku  
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public class FileAccessI implements Serializable{ ]iVoF N}^  
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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 >-<7 r?~  
RandomAccessFile oSavedFile; 9_\1cSk'  
long nPos; >&2n\HR\  
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public FileAccessI() throws IOException RF.8zea{O`  
{ @;H1s4OZ  
this("",0); P :D6w){  
}
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tD !$!\`O  
public FileAccessI(String sName,long nPos) throws IOException ]h0K*{  
{ lhhp6-r  
oSavedFile = new RandomAccessFile(sName,"rw"); jCv%[H7  
this.nPos = nPos; .#$D\cwV  
oSavedFile.seek(nPos); qECta'b&  
} *L~88-V^  
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public synchronized int write(byte[] b,int nStart,int nLen) zWEt< `1M  
{ 4GTB82V$  
int n = -1; gay6dj^  
try{ \3v}:E+3  
oSavedFile.write(b,nStart,nLen); 2zN%Z!a#J  
n = nLen; ?.b.mkJ  
} l:rT{l=8*  
catch(IOException e) %["V "{ z  
{ "<I*ViZ  
e.printStackTrace (); ISl-W1u}  
} 7BDoF!kCx  
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return n; vx8-~Oq{|;  
} o{wXq
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} &fYV FRVkq  
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> : ;*3  
/* z^
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**SiteInfoBean.java IHlTp0?
  
*/ lwuslt*E/  
package NetFox; \a}W{e=FNT  
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public class SiteInfoBean { z4yV1  
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private String sSiteURL; //Site's URL XKq}^M&gy  
private String sFilePath; //Saved File's Path <X,0\U!lL  
private String sFileName; //Saved File's Name 8~
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private int nSplitter; //Count of Splited Downloading File R7xEE7p
 
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public SiteInfoBean() Y"&1jud4xl  
{//nSplitter的缺省值为5 t*'U|K4L/  
//default value of nSplitter is 5 Ei[>%Ah  
this("","","",5); 8bIwRVA2\  
} +P. }<  
$-:j'e:j  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) %+,7=Wt-  
{ &=d0'3k>  
sSiteURL= sURL; ^7 oXJu=  
sFilePath = sPath; &0*=F%Fd  
sFileName = sName; +`)4jx)r/  
this.nSplitter = nSpiltter; f^63<gqY  
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} .:)nG(7f<  
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public String getSSiteURL() y! lEGA7  
{ BRg(h3 ED  
return sSiteURL; C_JDQByfL  
} JM-rz#;1  
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public void setSSiteURL(String value) }.j09[<  
{ RC| t-(Z  
sSiteURL = value; {tlt5p!4  
} -Ob89Z?2A  
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public String getSFilePath() )ZA3m_w]  
{ >(aGk{e1  
return sFilePath; jg_##Oha  
} Kq*D_Rh2  
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public void setSFilePath(String value) %wYGI  
{ .s)z
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sFilePath = value; jml 4YaGZ  
} I2$.o0=3Y  
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public String getSFileName() g}\Yl.  
{ ,?Bo x  
return sFileName; ~A5MzrvIO2  
} s$s]D\N  
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public void setSFileName(String value) rg^  
{ B.-1wZl  
sFileName = value; i!!1^DMrw  
} -8]M ,,?  
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public int getNSplitter() x*" 0dYH  
{ LS=HX~5C  
return nSplitter; 'L"dM9#>  
} )fo9Qwe  
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public void setNSplitter(int nCount) :i4>&4j  
{ h* to%N  
nSplitter = nCount; T!T6M6?  
} 6] ~g*]T  
} n' \poB?  
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/* ;c-J)Ky  
**Utility.java Q@in?};  
*/ CqRG !J  
package NetFox; BN?OvQ  
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public class Utility { IfH*saN7  
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public Utility() F .(zS(q  
{ ;eG,T-:
 
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} o0nKgq'w|x  
J8T?=%?=  
//线程睡眠 EMDsi2  
public static void sleep(int nSecond) /idQfff  
{ ="$9 <wt  
try{ 2\Vzfca  
Thread.sleep(nSecond); jORU+g  
} Z>)(yi9+  
catch(Exception e) 5s >UM@})  
{ [ET03 nZ  
e.printStackTrace (); ;BsPms@U  
} RN0@Q~oTI  
} @c<*l+Qc  
)>]~Y  
//日志 Wb_'X |"u  
public static void log(String sMsg) Wgt[ACioN  
{ OIuEC7XM^C  
System.err.println(sMsg); O43emL3  
} #)aUKFX  
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c&1:H1#  
public static void log(int sMsg) z(AhO  
{ &ggS!y'n  
System.err.println(sMsg); *LTFDC  
} &uh|!lD  
} ;E8.,#/a  
=AhXEu^  
6n{`t/  
/* ~mqiXr8  
**TestMethod.java `g2DN#q[0  
*/ `wJR^O!e  
package NetFox; 6]=R#d 7U  
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public class TestMethod { ):@XMECa  
o<*H!oyP\  
m"{D}(TA  
public TestMethod() CH6^;.  
{ ///xx/weblogic60b2_win.exe fa7I6 i  
try{ Pd99vq/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); *CHLs^)   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 8y-Sd\0g  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +ht -Bl  
fileFetch.start(); ;+%(@C51GE  
} s3+^q  
catch(Exception e){e.printStackTrace ();} _H:mBk,,  
zj ;'0Zu  
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}  vO85h  
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public static void main(String[] args) T+_pmDDN  
{ 5",@!1ju  
new TestMethod(); 8Bvc#+
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} iWbrX1 I+  
} [NE:$@  
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