http断点续传简单实现（java)

/* 3t22KY[`  
**SiteFileFetch.java 'bGL@H  
*/ O(
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package NetFox; V#.;OtF]  
import java.io.*; 'c<vj jIg  
import java.net.*; sUN>uroi !  
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public class SiteFileFetch extends Thread { n)uvN  
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SiteInfoBean siteInfoBean = null; //文件信息Bean C`+g:qT  
long[] nStartPos; //开始位置 XIh2Y\33ys  
long[] nEndPos; //结束位置 vn|u&}h  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 OLUQjvnU  
long nFileLength; //文件长度 ,oX48Wg_+  
boolean bFirst = true; //是否第一次取文件 4b=hFwr[?  
boolean bStop = false; //停止标志 CZRrb84  
File tmpFile; //文件下载的临时信息 =Xh^@OR  
DataOutputStream output; //输出到文件的输出流 Tl5K'3  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） h^^zR)EVb  
public SiteFileFetch(SiteInfoBean bean) throws IOException vK6YU9W~J  
{ {MdxIp[  
siteInfoBean = bean; |7]7~ 6l  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Qw4P{>|Y  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); UMwB.*  
if(tmpFile.exists ()) fx %Y(W#5  
{ 2K<rK(  
bFirst = false; *F*c  
read_nPos(); EW*
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} Mm`jk%:%]  
else n={}='  
{ r@FdxsCnGM  
nStartPos = new long[bean.getNSplitter()]; `bu3S}m7  
nEndPos = new long[bean.getNSplitter()]; u8qL?Aj^  
} (A O]f fBU  
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} :J]S+tQ)  
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public void run() .z&V!2zp  
{ 6cz%>@  
//获得文件长度 0i\ol9,bf  
//分割文件  hh<5?1  
//实例FileSplitterFetch / U1VE|T  
//启动FileSplitterFetch线程 !Sr^4R+Z  
//等待子线程返回 f gI.q  
try{ !3U1HS-i62  
if(bFirst) [
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{ o_&.R  
nFileLength = getFileSize(); J7$1+|"  
if(nFileLength == -1) ^4(CO[|c~  
{ a OR}  
System.err.println("File Length is not known!"); ya5a7  
} q88p~Ccoa  
else if(nFileLength == -2) #@H{Ypn`  
{ :,rD5aOQ  
System.err.println("File is not access!"); g`)3m,\  
} /{YUM~  
else ^y'xcq  
{ 8yz A W&q  
for(int i=0;i<nStartPos.length;i++) S`2MQL  
{ *cCr0\Z`  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Q>7#</i\.  
} ^k&zX!W  
for(int i=0;i<nEndPos.length-1;i++) x={t}qDS8  
{ !_E E|#`n  
nEndPos = nStartPos[i+1]; qyl~*r*  
}
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nEndPos[nEndPos.length-1] = nFileLength; q_>DX,A  
} <y'B !d#  
} rMxst  
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//启动子线程 asP>(Li  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; CvmZW$5Yo  
for(int i=0;i<nStartPos.length;i++) I'"*#QOX  
{ <kn#`w1U'  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R*.XbkW~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), .Y'kDuUu  
nStartPos,nEndPos,i); @A!Ef=R  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1w+OnJI?  
fileSplitterFetch.start(); O8SX#,3^}  
} GW'=/ z7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), S
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); xp/u, q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", }^G'oR1LF  
nEndPos = " + nFileLength); 25ul,t_Du  
// fileSplitterFetch[nPos.length-1].start(); x)G/YUv76  
HG@!J>YaD  
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//等待子线程结束 [rTV)JsTb  
//int count = 0; S)VuT0  
//是否结束while循环 )
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boolean breakWhile = false; la)f\Nk  
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while(!bStop) ] 5
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{ s`C#=l4  
write_nPos(); ;}f%bE  
Utility.sleep(500); BOL_kp"   
breakWhile = true; a6WE,4T9  
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for(int i=0;i<nStartPos.length;i++) ]*i>KR@G  
{ U@& <5'  
if(!fileSplitterFetch.bDownOver) ct~lt'L\  
{ 2:p2u1Q O  
breakWhile = false; >z^T~@
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break; dmlh;Z  
} MLBZmM '  
} U45/%?kE)  
if(breakWhile) M*c\=(  
break; IZAbW  
7Fy^K;V"  
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//count++; b17p;wS  
//if(count>4) Y%=A>~s*c:  
// siteStop(); r`<evwIe  
} ,nHz~Xi1t  
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;F5B)&/B  
System.err.println("文件下载结束！"); T7W+K7kbI  
} (O`=$e  
catch(Exception e){e.printStackTrace ();} xVl90ak  
} 8L=QfKr  
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//获得文件长度 |LNXu  
public long getFileSize() e#zGLxa  
{ Fa/i./V2  
int nFileLength = -1; p:4vjh=1h  
try{ H/, tE0ZV  
URL url = new URL(siteInfoBean.getSSiteURL()); } KMdfA  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G3U+BC23E  
httpConnection.setRequestProperty("User-Agent","NetFox"); "(C}Dn#  
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+Nza@B d  
int responseCode=httpConnection.getResponseCode(); d>AVUf<o~  
if(responseCode>=400) #%{\59/w  
{ M?\)&2f[Z  
processErrorCode(responseCode); '[juPI(!  
return -2; //-2 represent access is error S`6'~g  
} "RShsJZMH  
\JyWKET::_  
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String sHeader; *508PY  
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for(int i=1;;i++) f0[xMn0Tu  
{ @O3
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 22*t%{(  
//Utility.log(in.readLine()); ?"C]h s  
sHeader=httpConnection.getHeaderFieldKey(i); {jc~s~<#  
if(sHeader!=null) 6?a(@<k_  
{ TY#1Z )%  
if(sHeader.equals("Content-Length")) @qe>ph[UA  
{ 21WqLgT3 4  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); BT#>b@Xub  
break; 7<tqT @c  
} n$Pv2qw  
} *K98z ?  
else JZv]tJWq  
break; + zrwz\  
} C=m Y  
} Z8#I  
catch(IOException e){e.printStackTrace ();} wYxi
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catch(Exception e){e.printStackTrace ();} 5\'%zZ,l  
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Utility.log(nFileLength); N Hh  
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return nFileLength; Y5NbY02E  
} 87Uv+((H  
YH[_0!JY^  
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//保存下载信息（文件指针位置） ?rOb?cu-  
private void write_nPos() c@^:tB  
{ ]EcZ|c7o9y  
try{ WV@Tm$
r  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ICTtubjV"  
output.writeInt(nStartPos.length); M+E5PZ|_  
for(int i=0;i<nStartPos.length;i++) (p?3#|^  
{ Wu4Nq+  
// output.writeLong(nPos); *0hiPj:  
output.writeLong(fileSplitterFetch.nStartPos); y;Zfz~z  
output.writeLong(fileSplitterFetch.nEndPos); IX*S:7S[  
} ,%'0e/  
output.close(); Yz,!#ob$  
} ?|7+cz$g  
catch(IOException e){e.printStackTrace ();} Wi5|9  
catch(Exception e){e.printStackTrace ();} 3.0c/v5Go  
} \l:g{GnoT  
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//读取保存的下载信息（文件指针位置） xI: 'Hk1  
private void read_nPos() $i@EfujY  
{ u,akEvH~a  
try{ WDGGT.hG  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); c9uT`h  
int nCount = input.readInt(); z;C=d(|nN  
nStartPos = new long[nCount]; VqL 5f  
nEndPos = new long[nCount]; bQy%$7UmX,  
for(int i=0;i<nStartPos.length;i++) 8-"5|pNc  
{ ]pV1T  
nStartPos = input.readLong(); -k <9v.:  
nEndPos = input.readLong(); SO<m(o)G2  
} iHn!KV  
input.close(); b H?qijrC  
} DjzUH{6O  
catch(IOException e){e.printStackTrace ();} ' f$L  
catch(Exception e){e.printStackTrace ();} d `kM0C
 
} _qeuVi=A  
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private void processErrorCode(int nErrorCode) kLVn(dC "  
{ vif8{S  
System.err.println("Error Code : " + nErrorCode); e4Ox`gLa*p  
} %i-lx`U  
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vaR
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//停止文件下载 >I& jurU#  
public void siteStop() ;:4P'FWm^  
{ @ 9 {%Kn  
bStop = true; \`/E !ub  
for(int i=0;i<nStartPos.length;i++) akhL\-d)al  
fileSplitterFetch.splitterStop(); `8(h,aj;  
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} M7DLs;sD  
} r)p2'+}pV  
//负责部分文件的抓取 9c6GYWIFt&  
**FileSplitterFetch.java 43>9)
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*/ P-+M,>vNy[  
package NetFox; }xb_s  
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import java.io.*; 'cZMRRc<  
import java.net.*; Y=a v8Y|`  
*`ZB+ \*  
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public class FileSplitterFetch extends Thread { H^D 3NuUC  
!ww:O|0  
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String sURL; //File URL GsIwY {d  
long nStartPos; //File Snippet Start Position a|QE *s.  
long nEndPos; //File Snippet End Position *BLe3dok(  
int nThreadID; //Thread's ID .?rbny  
boolean bDownOver = false; //Downing is over Dxt),4%P  
boolean bStop = false; //Stop identical 1E
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FileAccessI fileAccessI = null; //File Access interface
@S}/g/+2  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Ot`LZ"H:  
{ t7w-TJvP  
this.sURL = sURL; z\f
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this.nStartPos = nStart; Xhcn]  
this.nEndPos = nEnd; wMb)6YZs  
nThreadID = id; O^9CV*]!n  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 jR{-  
} `$s)X$W?  
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public void run() z`k El@  
{ |KL')&"  
while(nStartPos < nEndPos && !bStop) %#~((m1  
{ eV"!/A2:N5  
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try{ 1T ( u  
URL url = new URL(sURL); g;pR^D'M5C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1/B]TT  
httpConnection.setRequestProperty("User-Agent","NetFox"); !fY7"E{%%  
String sProperty = "bytes="+nStartPos+"-"; Ve{n<{P  
httpConnection.setRequestProperty("RANGE",sProperty); xfjd5J7'  
Utility.log(sProperty); M!1U@6n!=)  
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InputStream input = httpConnection.getInputStream(); w OI^Q~  
//logResponseHead(httpConnection); x^G'rF"nT  
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byte[] b = new byte[1024]; (n,u|}
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int nRead; /F.Wigv  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) E<tK4?i"  
{ j^flwk  
nStartPos += fileAccessI.write(b,0,nRead); {( #zcK  
//if(nThreadID == 1) iPq &Y*  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bLzs?eos  
} &-%>qB|*  
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Utility.log("Thread " + nThreadID + " is over!"); UiH!Dl}<  
bDownOver = true; }pVTTs`  
//nPos = fileAccessI.write (b,0,nRead); ]mQw,S)/"  
} [}OgSP9i  
catch(Exception e){e.printStackTrace ();} r> k-KdS  
} -&|:0#@P  
} {Z> M  

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//打印回应的头信息 :w`3cwQ  
public void logResponseHead(HttpURLConnection con) '$G"[ljr  
{ ).5RPAP  
for(int i=1;;i++)
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{ =^&%9X  
String header=con.getHeaderFieldKey(i); z0%\OhuCcf  
if(header!=null) QzOkpewf  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 6KHN&P  
Utility.log(header+" : "+con.getHeaderField(header)); %' $o"  
else r X'*|]  
break; |&3x#1A  
} tz^/J=)"  
} |TsE-t*E}  
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public void splitterStop() OFk8>"|  
{ Bc7V)YK  
bStop = true; @L/o\pvc  
} JL=U,Mr6  
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} ^n1%OzGK#  
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/* N_eX/ux  
**FileAccess.java *N'K/36;  
*//文件访问(定位，写) sRSz}]  
package NetFox; rxnFrx  
import java.io.*; v+7kU=  
ldha|s.*  
O.aG[wm8  
public class FileAccessI implements Serializable{ r3E!dTDWq  
/1N6X.Zb  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 W>_]dPBS/  
RandomAccessFile oSavedFile; j9Ybx#  
long nPos; Snp|!e  
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public FileAccessI() throws IOException -fhN"B)  
{ 6E(Qx~iL  
this("",0); +#U|skl  
} =4V&*go*\  
2M#M"LHo  
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public FileAccessI(String sName,long nPos) throws IOException )?_#gLrE6  
{ \(226^|j  
oSavedFile = new RandomAccessFile(sName,"rw"); mxor1P#|  
this.nPos = nPos; KT]Pw\y5  
oSavedFile.seek(nPos); b0iSn#$  
} 4tL<q_  
!.2<| 24  
*6HTV0jv  
public synchronized int write(byte[] b,int nStart,int nLen) A-:O`RK  
{ "KcA  
int n = -1; W3`>8v1?o  
try{ ga?*DI8w  
oSavedFile.write(b,nStart,nLen); ^u3V E  
n = nLen; Y5fLmPza  
} vJAZ%aW  
catch(IOException e) Gt9&)/#  
{ 06jqQ-_`h  
e.printStackTrace (); U,nEbKJgk  
} WJI[9@^I~  
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return n; lu Q~YjH  
} N0#JOu}~  
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} C6rg<tCH  
B"%{i-v>**  
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/* iNMx"F0r  
**SiteInfoBean.java o)'y.-@Q  
*/ Ef<b~E@  
package NetFox; ZvcJK4hi  
DY[$"8Kxcp  
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public class SiteInfoBean { fGmT_C0t  
vTv]U5%:>%  
}NsUnbxT  
private String sSiteURL; //Site's URL #-h\.#s  
private String sFilePath; //Saved File's Path ^e+
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private String sFileName; //Saved File's Name 6~*9;!th  
private int nSplitter; //Count of Splited Downloading File O]qU[y+  
t(="h6i  
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public SiteInfoBean() ,m,)
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{//nSplitter的缺省值为5 /T.KbLx~q  
//default value of nSplitter is 5 P6MRd/y |  
this("","","",5); hR.@b*q?R  
} ZY:[ekm%4Z  
1h.)#g?{  
]THPSw_y8  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) bGorH=pb5R  
{ 7#wn<HDY%  
sSiteURL= sURL;  f3UXCp  
sFilePath = sPath; $Y 7c  
sFileName = sName; &.Zb,r$Y  
this.nSplitter = nSpiltter; <7Ae-!>x  
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&7_Qd4=08w  
} _!|/ ;Nk  
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+&["HoKg}&  
public String getSSiteURL() H)(:8~c,p  
{ iPrLwheb  
return sSiteURL; w}CmfR
 
} x
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?MQ.% J  
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public void setSSiteURL(String value) owPm/
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{ +b3^.wkq  
sSiteURL = value; M2U&?V C!  
} SvR7eC  
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public String getSFilePath() mJM_2Ab  
{ yZ!T8"mz{  
return sFilePath; n>'Kp T9|  
} RW P<B0)  
[=|jZVhT  
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public void setSFilePath(String value) "al`$%(
 
{ ?@n/v F  
sFilePath = value; \Y}3cE  
} l (3bW1{n  
P<K){V  
O=9-Qv|  
public String getSFileName() CpQN,-4  
{ pZU9^Z?~6  
return sFileName; %N#%|2B  
} !|<=ZF2  
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!  
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public void setSFileName(String value) 1$
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{ =rR~`  
sFileName = value; sm$(Y.N  
} [2|kl l  
!!o8N<NU  
|]Qg7m,O  
public int getNSplitter() FaBqj1O1  
{ iS
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return nSplitter; MfmACd^3$  
} al`3Lu0  
:eZh'-c?  
|7#[ (%D!  
public void setNSplitter(int nCount) [p=*u,-  
{ }y%oT P&  
nSplitter = nCount; X=C1/4wU  
} Tz9`uW~Mf  
} F_bF  
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a {ab*tM  
/* .IJ_jt-^d  
**Utility.java 1jX3ey~  
*/ 3/#:~a9Q  
package NetFox; )a3IQrf=  
/CTc7.OYt  
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public class Utility { $'pNp B#vH  
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;
}<  
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public Utility() {Q<$Uo6V  
{ *H[Iq!@  
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IHp_A  
} 8UkKU_Uso  
"KJ%|pg_C  
//线程睡眠 wZh:F !  
public static void sleep(int nSecond) DKVT(#@T  
{ L^^4=ao0  
try{ d^(1TNS  
Thread.sleep(nSecond); M.td^l0  
} Tg3!Rq55  
catch(Exception e) 1.q_f<
U  
{ z>R#H/h+  
e.printStackTrace (); VYw%01#  
} FecktD=  
} +}Av-47`h  
gN {'UDg  
//日志 dO7;}>F$n  
public static void log(String sMsg) _IeU+tS  
{ 6bBdIqGb}  
System.err.println(sMsg); dC}`IR  
} +%\oO/4Fs  
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u-"
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public static void log(int sMsg) V,EF'-F  
{ &6Il(3-^  
System.err.println(sMsg); fa.0I~  
} (cv!Y=]  
} TCvSc\Q[:1  
U/;]zdP.K  
A"Q@W<.  
/* nW?R"@Zm  
**TestMethod.java ?*r!{3T ,u  
*/ ;3C:%!CdA]  
package NetFox; nU`Lhh8y  
Lv1{k\aw  
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public class TestMethod { T@^]i&  
x
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public TestMethod() 8
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{ ///xx/weblogic60b2_win.exe v[<Bjs\q5  
try{ /,|CrNwY*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); NBl __q  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); \Btk;ivg  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }gf}eH  
fileFetch.start(); |Y_ -  
} P"7ow-  
catch(Exception e){e.printStackTrace ();} DlE_W+F  
K'6[J"dB  
>{Rb 3Z]  
} 3]E(mRX  
'4;6u]d)2  
iz}sM>^  
public static void main(String[] args) (*l2('e#@  
{ `{FwTZ=6{  
new TestMethod(); 8V4V3^_xs  
} gp|1?L54  
} |;;!8VO3J  
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