http断点续传简单实现（java)

/* Az-!X!O*f  
**SiteFileFetch.java yb)qg]2  
*/ IM,4Si2  
package NetFox; :G]t=vr1  
import java.io.*; s%8,'3&  
import java.net.*; 8'NT_NPNb  
 FsQoQ#*  
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public class SiteFileFetch extends Thread { [)kuu  
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SiteInfoBean siteInfoBean = null; //文件信息Bean <_]W1V:0  
long[] nStartPos; //开始位置 .$ YYN/+W  
long[] nEndPos; //结束位置 6{0MprY  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 REh\WgV!u  
long nFileLength; //文件长度 S<-5<Pg  
boolean bFirst = true; //是否第一次取文件 1Dhu5h
t  
boolean bStop = false; //停止标志 e}P@7e h  
File tmpFile; //文件下载的临时信息 K
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DataOutputStream output; //输出到文件的输出流 \ H#"  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） G]{^.5  
public SiteFileFetch(SiteInfoBean bean) throws IOException |n^rI\p%  
{ .g?D3$|K  
siteInfoBean = bean; >3~)2)Q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Oi]B%Uxy=  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Jr= fc*f  
if(tmpFile.exists ()) [LUqF?K&  
{ T LF'7ufq  
bFirst = false; Le{.B@2-"  
read_nPos(); Q04 `+Vr  
} .:GOKyr(~  
else & JJ*?Dl  
{ O{Mn\M6  
nStartPos = new long[bean.getNSplitter()]; :z *jl'L  
nEndPos = new long[bean.getNSplitter()]; K V  
} -WR<tkK  
2;J\Z=7  
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} SJlE!MK  
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[hk/Rp7{  
public void run() %Pj}  
{ ~*UY[!+4^=  
//获得文件长度 7,8TMd1`M  
//分割文件 8?x:PkK  
//实例FileSplitterFetch >"|t*kS  
//启动FileSplitterFetch线程 tmM; Z(9t  
//等待子线程返回 Y>ATL  
try{ 3-)}.8F  
if(bFirst)
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{ DL,]iJm  
nFileLength = getFileSize(); TIR Is1  
if(nFileLength == -1) (<-m|H};  
{ ll- KK`Ka  
System.err.println("File Length is not known!"); 0 0|!g"E>$  
} B7YE+  
else if(nFileLength == -2) & 9 c^9<F  
{ eH[i<Z  
System.err.println("File is not access!"); x5Fo?E  
} zA:q/i  
else jUgx ;=  
{ A wk1d  
for(int i=0;i<nStartPos.length;i++) ;sqxFF@  
{ zK{}   
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 6Z2|j~  
} 9_e_Ne`i`?  
for(int i=0;i<nEndPos.length-1;i++) 3(vm'r&5n>  
{ ='_3qn.  
nEndPos = nStartPos[i+1]; i\gt @  
} 79-5
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nEndPos[nEndPos.length-1] = nFileLength; `&xdSH  
} Uj3HAu  
} !c-MC|  
j]]5&u/l  
n2Mpo\2  
//启动子线程 pG"hZB3)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; AZA5>Y
 
for(int i=0;i<nStartPos.length;i++) @$ lX%p>  
{ gj
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :XPat93w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \pTv;(  
nStartPos,nEndPos,i); {XUSw8W'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kBk2mMZ  
fileSplitterFetch.start(); oDJ &{N|  
} ! hEZV&y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nZc6 *jiz  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); H~SU:B:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", D ] n|d+  
nEndPos = " + nFileLength); U>m{B|H  
// fileSplitterFetch[nPos.length-1].start(); ]=I2:Rb  
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n  
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//等待子线程结束 1uR@ZK  
//int count = 0; 3d7A/7S  
//是否结束while循环 W1t_P&i  
boolean breakWhile = false; F:[[
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]` A*7  
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while(!bStop) n<<arO"cv  
{ ?~#[cx  
write_nPos(); Z7[S698  
Utility.sleep(500); J^%E$s  
breakWhile = true; ^Jdg%U?  
#o9CC)q5G  
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for(int i=0;i<nStartPos.length;i++) jO|`aUYTf  
{ yf`_?gJ6d  
if(!fileSplitterFetch.bDownOver)  cz>)6#&O  
{ TBba3%  
breakWhile = false; a2i:fz=[  
break; jsr
)  
} :`"-Jf  
} G\,B*$3   
if(breakWhile) h4MBw=Tz~  
break; 0Js5 ' 9}H  
rg]b$tL~  
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//count++; a|[f%T<<  
//if(count>4) 3u^wK  
// siteStop(); qe(C>qjMbG  
} :,
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System.err.println("文件下载结束！"); A
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} @,6*yyO  
catch(Exception e){e.printStackTrace ();} X.,R%>O}`P  
} IB 4L(n1  
1p&=tN  
=?wDQ:  
//获得文件长度 QR8]d1+GV  
public long getFileSize() nGc'xQy0  
{ PU B0H  
int nFileLength = -1; )J+rt^4|  
try{ 7Q~W}`Qv'  
URL url = new URL(siteInfoBean.getSSiteURL()); T2)CiR-b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Uspv^O9_  
httpConnection.setRequestProperty("User-Agent","NetFox"); {TMng&
 
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int responseCode=httpConnection.getResponseCode(); p|a`Q5z!  
if(responseCode>=400) I3T;
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{ DW:\6k  
processErrorCode(responseCode); [eTEK W]  
return -2; //-2 represent access is error o8%o68py  
} MTgf.  
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String sHeader; x;~@T9.  
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for(int i=1;;i++) <@+L^Ps~z  
{ f(!cz,y^\*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); xCT2
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//Utility.log(in.readLine()); [
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sHeader=httpConnection.getHeaderFieldKey(i); ",,.xLI7  
if(sHeader!=null) r;H#cMj  
{ `022gHYv  
if(sHeader.equals("Content-Length")) +
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{ +ek6}f
#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); V|HO*HiB3  
break; (I>SqM Y  
} |o(te  
} f.oY:3h:  
else aM,g@'.=  
break; 2~r2ErtS  
} 6Rq +=X  
} e},:QL0X  
catch(IOException e){e.printStackTrace ();} mRGr+m  
catch(Exception e){e.printStackTrace ();} nKtRJ,>  
 :fy,%su  
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Utility.log(nFileLength); i??+5o@uTF  
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return nFileLength; <4/q5
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} |q\i, }  
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s+G(N$0U  
//保存下载信息（文件指针位置） {`J!DFfur  
private void write_nPos() (r}StR+  
{ $`t2SD  
try{ +#(GU9_i+M  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?@Tsd@s~r  
output.writeInt(nStartPos.length); Yc3\
 
for(int i=0;i<nStartPos.length;i++) gQY`qz  
{ _ |HA\!  
// output.writeLong(nPos); $`0,N_C<}  
output.writeLong(fileSplitterFetch.nStartPos); _25PyG  
output.writeLong(fileSplitterFetch.nEndPos); =>A}eR1Y  
} <&)zT#"  
output.close(); Pmr'W\aIR  
} tO"AeZe%|  
catch(IOException e){e.printStackTrace ();} 4U'sBaY!K  
catch(Exception e){e.printStackTrace ();} dI=&gz  
} &fkH\o7)  
7/
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//读取保存的下载信息（文件指针位置） o4z|XhLr  
private void read_nPos() T`<Tj?:^&  
{ [E2".F3  
try{ Zny9TP  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {%,4P_m  
int nCount = input.readInt(); >^<;;8Xh  
nStartPos = new long[nCount]; i-dosY`81  
nEndPos = new long[nCount]; ~52'iI)Mw  
for(int i=0;i<nStartPos.length;i++) >:FmAey  
{ v"Ryg]^_  
nStartPos = input.readLong(); \]\GDpu[  
nEndPos = input.readLong(); !Ow M-t  
} X;vUz  
input.close(); 8hyXHe  
} [+}0K{(O=  
catch(IOException e){e.printStackTrace ();} /@DJf\`vM  
catch(Exception e){e.printStackTrace ();} YuzVh9jTI  
} >I&s%4  
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@|'9nPern  
private void processErrorCode(int nErrorCode) V^}$f3\B  
{ {sq:vu@NC  
System.err.println("Error Code : " + nErrorCode); a/%qn-i|p  
} "#f5jH  
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L}g#h+GP[  
//停止文件下载 wW<u)|>ye  
public void siteStop() uX1{K%^<TW  
{ n1'i!NWt  
bStop = true; 7s}F`fjKP  
for(int i=0;i<nStartPos.length;i++) 1h)K3cC  
fileSplitterFetch.splitterStop(); Hbu :HFJ!  
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} <f
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} zP c54>f  
//负责部分文件的抓取 @x*,fk  
**FileSplitterFetch.java }ZiJHj'<  
*/ eV;nTj  
package NetFox; Q yQ[H  
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>+:cTQ|q  
import java.io.*; u:w
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import java.net.*; xKepZ  
sY]pszjT  
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public class FileSplitterFetch extends Thread { : 'jVA  
87+u`~  
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String sURL; //File URL PklJU:Pu\U  
long nStartPos; //File Snippet Start Position 4 .(5m\s!  
long nEndPos; //File Snippet End Position ~!%G2E!  
int nThreadID; //Thread's ID <si
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boolean bDownOver = false; //Downing is over k6\&[BQs  
boolean bStop = false; //Stop identical =<ht@-1  
FileAccessI fileAccessI = null; //File Access interface 6G_{N.{(  
6eNBldP!  
3
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException N5xI;UV9'  
{ }C~9?Y  
this.sURL = sURL; FL0yRF5  
this.nStartPos = nStart; rK'O 85)eU  
this.nEndPos = nEnd; xa{.hp?  
nThreadID = id; lhBAT%U\  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 J10&iCr{r*  
} QG@Z%P~,E  
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public void run() )}i2x:\|_  
{ rDc$#  
while(nStartPos < nEndPos && !bStop) c/(Dg$DbX  
{ =65XT^  
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try{ i+I1h=  
URL url = new URL(sURL); VZ9`Kbu  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V
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httpConnection.setRequestProperty("User-Agent","NetFox"); _m%Ab3iT~  
String sProperty = "bytes="+nStartPos+"-"; 9.6ni1a'  
httpConnection.setRequestProperty("RANGE",sProperty); x Y}.mP  
Utility.log(sProperty); gN<J0c)  
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,
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InputStream input = httpConnection.getInputStream(); #210 Yp#  
//logResponseHead(httpConnection); ^Q!A4qOQ  
&u(pBr8B  
&nY#GHB  
byte[] b = new byte[1024]; O}6*9X
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int nRead; 9*r l7  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) $]^Io)}f@  
{ m\|E
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nStartPos += fileAccessI.write(b,0,nRead); aQj6XGu  
//if(nThreadID == 1) H*",'`|-  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); W4nhPH(  
} ;g<y{o"Q3p  
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Utility.log("Thread " + nThreadID + " is over!"); N#X* 0i"  
bDownOver = true; i> {0h3Y  
//nPos = fileAccessI.write (b,0,nRead); @U =~c9  
} gaE8\JSr  
catch(Exception e){e.printStackTrace ();} =}SLQdT  
} Hig.` P  
} W/%9=g$m  
D\DwBZ>  
5hDPX\  
//打印回应的头信息 TR'_v[uK3  
public void logResponseHead(HttpURLConnection con) i=V2 /W}  
{ jk%H+<FU`  
for(int i=1;;i++) k<rJm P{  
{ 6ywOL'OBM  
String header=con.getHeaderFieldKey(i); mdcsL~R  
if(header!=null) J{nA ?[  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )6px5Vwz  
Utility.log(header+" : "+con.getHeaderField(header)); hE4qs~YB!  
else ^Qxv5HS2  
break; )X8N|W>vh  
} |jcIn[)=  
} V&lx0Dy  
6Z@T /"mU(  
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public void splitterStop() Ghar hJ>v  
{ d8p5a C+E  
bStop = true; qGP}  
}
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} LFvZ 7M\\  
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jQ-2SA O  
/* +Y>oNX1KN  
**FileAccess.java ]y"=/Nu-Ja  
*//文件访问(定位，写) .P ??N  
package NetFox; 8,&Y\b`..  
import java.io.*; JX#0<U|L  
.(yJ+NU  
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public class FileAccessI implements Serializable{ NT9|``^Z  
*thm)Mn  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 J.c yb  
RandomAccessFile oSavedFile; @Z<Z//^k  
long nPos; | S
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public FileAccessI() throws IOException n`T4P$pt  
{ Bz>5OuOVS\  
this("",0); ,MG`}*N}  
} }R_Rw:W  
d\r-)VWSr"  
@eq.&{&  
public FileAccessI(String sName,long nPos) throws IOException &+yoPF  
{ ;ssI8\LG  
oSavedFile = new RandomAccessFile(sName,"rw"); y8} /e@&  
this.nPos = nPos; J_9[xmM  
oSavedFile.seek(nPos); XcL%0%`  
} mo&9=TaG  
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'p[B`Ft3F  
public synchronized int write(byte[] b,int nStart,int nLen) \[ 4y  
{ =uR3|U(.|u  
int n = -1; (]zi;  
try{ -oB=7+g  
oSavedFile.write(b,nStart,nLen); @0 [^SU?  
n = nLen; Dd:^ {  
} $ k_6  
catch(IOException e) @\W-=YKLg  
{ NnaO!QW%  
e.printStackTrace (); K@a#^lmd  
} R'fEw3^  
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return n; K\.tR  
} A,3qjd,$ c  
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} )RQQhB  
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/* J5Ti@(G5V  
**SiteInfoBean.java zU_dk'&,  
*/ %OP|%^2  
package NetFox; Fqh./@o  
(B!DBnq  
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public class SiteInfoBean { '~1Zr uO  
nC)"% Sa  
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private String sSiteURL; //Site's URL F_4Et  
private String sFilePath; //Saved File's Path E0+~c1P-  
private String sFileName; //Saved File's Name U\M9sTqo  
private int nSplitter; //Count of Splited Downloading File
ES8(:5  
\r [@A3O  
7OS i2  
public SiteInfoBean() 08! _B\  
{//nSplitter的缺省值为5 4&v&XLkb  
//default value of nSplitter is 5 f>3)}9?xc}  
this("","","",5); kfZ(
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} 0|8cSE< i  
{SD%{  
ekqS=KfWl;  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) e>bARK<  
{ ~ H/ZiBL@  
sSiteURL= sURL; p"j&s  
sFilePath = sPath; (!YJ:,!so  
sFileName = sName; $8SSu|O+x  
this.nSplitter = nSpiltter; pgZQ>%  
QS1lg  
($W%&(:/  
} zS h9`F  
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COmu.'%*  
public String getSSiteURL() ^YB2E*  
{ }Z
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return sSiteURL; +;M 5Sp  
} 0)ZLdF_6  
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public void setSSiteURL(String value) Q{an[9To~P  
{ T8x8TN"  
sSiteURL = value; 1kR. .p<"  
} {-f%g-@L6|  
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public String getSFilePath() ]>%2,+5  
{ 3i'01z  
return sFilePath; VL'wrgk  
} {3kz\FS  
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zQ<;3+*  
public void setSFilePath(String value) *'\HG  
{ G?61P[j7  
sFilePath = value; {FS)f  
} #;?/fZjY  
[x]~G  
Ih4$MG6QC  
public String getSFileName() P"]l/  
{ gGx(mX._L?  
return sFileName; {J,4g:4G  
} t1yOAbI  
)VqPaKZl  
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public void setSFileName(String value) lnm@DWhf  
{ nwC*w
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sFileName = value; J@}PySq  
} ^ meU&  
96J]g*o(uU  
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public int getNSplitter() $)BPtGMGo  
{ rK`^A  
return nSplitter; *<6dB#' J  
} 0CK
  
*c&OAL]  
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public void setNSplitter(int nCount) A1`6+8}o;b  
{ lNtxM"G&  
nSplitter = nCount; 1i_%1Oip  
} 3la`S$c  
} K<`W>2"  
)Q>Ao.  
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/* @+Sr~:K  
**Utility.java UUb0[oy  
*/ |5X59! JL  
package NetFox; xXa4t4gR  
T?6<1n
U)  
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public class Utility { 56.JBBZZ  
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public Utility() svb7-.!  
{ u86PTp+  
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TW70z]B  
} [{Q$$aV1  
o?Cc  
//线程睡眠 qswC>Gi  
public static void sleep(int nSecond) ZkQ6~cM  
{ ZGsd cnz  
try{ yXv@yn  
Thread.sleep(nSecond); u/-EVCHr y  
} _nEVmz!zg  
catch(Exception e) ;134$7!Y  
{ :FtV~^Z  
e.printStackTrace (); F]r'j ZL  
} \%.o
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} jYFmL_{  
Sy4|JM-5  
//日志 ?!/8~'xA6  
public static void log(String sMsg) =Y6W Qf  
{ '5[(QM5Gi&  
System.err.println(sMsg); 47Bg[  
} +PI}$c-|`  
OVU)t]  
dv3u<XM~  
public static void log(int sMsg) W*#5Sk  
{ -C}"1|P!  
System.err.println(sMsg); ?A_+G 5  
} JX[]u<h?  
} (xVx|:R[<H  
ls!A'@J  
!Ko>   
/* !G0Mg; ,  
**TestMethod.java VwZ~ntk  
*/ ;in-)`UC!  
package NetFox; :yJ([  
^_DwuY  
Zv=pS (9  
public class TestMethod { >A6W^J|[  
wy${EY^h  
ilHf5$  
public TestMethod() &z:bZH]DH  
{ ///xx/weblogic60b2_win.exe
?eX/vqk  
try{ yt="kZ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); As,e.V5!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); LP|YW*i=IQ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); rxyeix  
fileFetch.start(); JS%LJ_J  
} w5~j|c=_W  
catch(Exception e){e.printStackTrace ();} -l[$+Kw1S  
xS5 -m6/  
]4c+{  
} .74C~{}$  
Pmd[2/][  
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public static void main(String[] args) <!UnH6J.b  
{ 9X;*GC;d  
new TestMethod(); ]H}2|~c  
} 7(h@5  
} "G.X=, V  
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