http断点续传简单实现（java)

/* j,gM+4V^  
**SiteFileFetch.java qB`0^V  
*/ O(c4iWm  
package NetFox; %>x0*T$$  
import java.io.*; .q|xMS}4  
import java.net.*; 7@e[:>e  
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public class SiteFileFetch extends Thread { 6i?kkULBS  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Bt`r6v;\  
long[] nStartPos; //开始位置 /M{)k_V  
long[] nEndPos; //结束位置 E`sapk  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 e2VL/>y`  
long nFileLength; //文件长度 ;Kq<',u~  
boolean bFirst = true; //是否第一次取文件 n=#[Mi $Y  
boolean bStop = false; //停止标志 +(=[M]5#n  
File tmpFile; //文件下载的临时信息 S4uR\|  
DataOutputStream output; //输出到文件的输出流 #q^>qX y  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） G41$oalQ1  
public SiteFileFetch(SiteInfoBean bean) throws IOException G1n>@Y'j''  
{ g'l7Jr3  
siteInfoBean = bean; })yb   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .bY1N5=sz  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); +MZ2e^\F  
if(tmpFile.exists ()) 'KW+Rr~tZn  
{ 7u&H*e7  
bFirst = false; a7 '\*  
read_nPos(); im^I9G  
} .jG.90  
else 8)2u@sx%  
{ lfI7&d*  
nStartPos = new long[bean.getNSplitter()]; ]T28q/B;k  
nEndPos = new long[bean.getNSplitter()]; b^|,9en  
} ?),K=E+=U  
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}   
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} s\K-(`j}  
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public void run() &<;nl^  
{ a6K$omu  
//获得文件长度 4QN6BZJ5  
//分割文件 C J}4V!;|  
//实例FileSplitterFetch =*O9)$b  
//启动FileSplitterFetch线程 O'?lW~CD.>  
//等待子线程返回 j(2tbW
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try{ oU{-B$w  
if(bFirst) L:];[xa%  
{ hF?\K^tF  
nFileLength = getFileSize(); Q0oDl8
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if(nFileLength == -1) ZBh@%A  
{ 'XjHB!!hU  
System.err.println("File Length is not known!"); l>Oe ,`9O  
} PeR<FSF ,i  
else if(nFileLength == -2) }Q,C;!'"  
{ ^<H#dkECG  
System.err.println("File is not access!"); <MDFfnj  
} c9TkIe  
else [E&"9%K  
{ TuT=  
for(int i=0;i<nStartPos.length;i++) B\~3p4S  
{ =?QQb>  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "nS{ ;:  
} Uu<sntyv  
for(int i=0;i<nEndPos.length-1;i++) Pp")hFx  
{ #p^pvdvh3  
nEndPos = nStartPos[i+1]; U*#E aL  
} :r[-7 [/  
nEndPos[nEndPos.length-1] = nFileLength; '"NdT7*+  
} JZ*?1S>  
} ~s^6Q#Z9|  
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//启动子线程 O"w_sw  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; gj(l&F *@  
for(int i=0;i<nStartPos.length;i++) a>e 1jM[  
{ 2LK*Cv[  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;@$,
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), nHL>}Yg  
nStartPos,nEndPos,i); pl? J<48  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); SF}L3/C&h  
fileSplitterFetch.start(); kA$;vbm  
} '[M2Q"X  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), gbi~!S-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); w[7HY@[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", l=G#gKE  
nEndPos = " + nFileLength); a}8>(jtSt  
// fileSplitterFetch[nPos.length-1].start(); n@8{FoF  
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//等待子线程结束 7UnO/K7oB.  
//int count = 0; v?iH}7zb%Q  
//是否结束while循环 vt7
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boolean breakWhile = false; :=fHPT  
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while(!bStop) a[OLS+zf!P  
{ 
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write_nPos(); uaMmiR  
Utility.sleep(500); i_9/!D  
breakWhile = true; Kwmo)|7uPU  
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for(int i=0;i<nStartPos.length;i++) sjbC~Te--  
{ eT \Q  
if(!fileSplitterFetch.bDownOver) #pxet  
{ #hiDZ>nr  
breakWhile = false; %y~]3XWik  
break; sJ*U Fm{  
} vG=$
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} LGue=Hkp  
if(breakWhile) g{.@|;d<p  
break; <\Dl#DH  
)=y6s^}  
|Szr=[  
//count++; ~.=HN}E  
//if(count>4) oEf^o*5(  
// siteStop(); $XzlW=3y  
} )Syf5I  
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System.err.println("文件下载结束！"); Jywz27j  
} \^Q)`Lqp:g  
catch(Exception e){e.printStackTrace ();} Z#t.wWSq  
} E<[ bgL  
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//获得文件长度 @Pg@ltUd  
public long getFileSize() " ~hjB  
{ H s 3*OhK\  
int nFileLength = -1; "!eT  
try{ :l[Q  
URL url = new URL(siteInfoBean.getSSiteURL()); U-N/
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b-gVRf#F  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2n,
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int responseCode=httpConnection.getResponseCode(); y^fU_L?p  
if(responseCode>=400) sX?7`n1U  
{ UjK&`a;V  
processErrorCode(responseCode); SQ.Wj?W)  
return -2; //-2 represent access is error Dy'
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} qt;Tfuo  
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String sHeader; [wxI X  
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for(int i=1;;i++) qf
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{ &xT~;R^  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ZX}"  
//Utility.log(in.readLine()); )4C6+63OD&  
sHeader=httpConnection.getHeaderFieldKey(i); -C]a2  
if(sHeader!=null) Tj~#Xc  
{ smS0Rk  
if(sHeader.equals("Content-Length")) M)RQIl5  
{ c3BL2>c  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));
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break;
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} !~kzxY  
} $S("-3  
else f@g  
break; n#,l&Bx  
} u{d`  
} nAj2k  
catch(IOException e){e.printStackTrace ();} }Elce}  
catch(Exception e){e.printStackTrace ();} cW%O-  
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Utility.log(nFileLength); BS.6d}G4  
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return nFileLength; _L.yt5_  
} 2J;CiEB  
+.uk#K0o  
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//保存下载信息（文件指针位置） |Q;1;QXd  
private void write_nPos() H|O}Dsj  
{ 5Yr$dNe  
try{ hdb4E|'A  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?^Ux+mVE  
output.writeInt(nStartPos.length); jXR+>=_  
for(int i=0;i<nStartPos.length;i++) <rF  
{ 7mBL#T2   
// output.writeLong(nPos); z5/O8}Gz@  
output.writeLong(fileSplitterFetch.nStartPos); </p.OaNe  
output.writeLong(fileSplitterFetch.nEndPos); \]El%j4  
} &o.SmkJI  
output.close(); B/}>UHM  
} 9\2&6H  
catch(IOException e){e.printStackTrace ();} .@V>p6MV  
catch(Exception e){e.printStackTrace ();} B:.rp.1   
} aQFHB!  
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//读取保存的下载信息（文件指针位置） \:7EKzQ  
private void read_nPos() //|Vj | =  
{ Hq$|j,&?  
try{ g7-K62bb  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ^Quy64M  
int nCount = input.readInt(); RJD3o_("K  
nStartPos = new long[nCount]; '~0&m]N  
nEndPos = new long[nCount]; a/fYD2uNo  
for(int i=0;i<nStartPos.length;i++) K(2s%  
{ QeoDq  
nStartPos = input.readLong(); f'S"F  
nEndPos = input.readLong(); N5DS-g
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} b.&YUg[#  
input.close(); {'(8<n5
7  
} 8),Y|4  
catch(IOException e){e.printStackTrace ();} TH &B9  
catch(Exception e){e.printStackTrace ();} g~b'}^J  
} tHeLq*))  
>wwEa4   
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private void processErrorCode(int nErrorCode) (WvA9s{/  
{ aT#|mk=\  
System.err.println("Error Code : " + nErrorCode); 0M?}S~p]  
} dGe  
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//停止文件下载 \\JXY*DA:+  
public void siteStop() T~>:8i  
{ {'%=tJ[YX  
bStop = true; TF>F7v(,45  
for(int i=0;i<nStartPos.length;i++) da@ .J9  
fileSplitterFetch.splitterStop(); ^(R gSMuT`  
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} 2_Z60]  
} RU=%yk-gM  
//负责部分文件的抓取 &3V4~L1aEg  
**FileSplitterFetch.java g,nE
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*/ XJ9>a-{  
package NetFox; 2Z~ofrj  
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import java.io.*; g=Lt2UIJ  
import java.net.*; ]Ea-?IhD  
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public class FileSplitterFetch extends Thread { 4.TG&IQ nN  
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String sURL; //File URL <3KrhhH  
long nStartPos; //File Snippet Start Position ;<\*(rUe  
long nEndPos; //File Snippet End Position @Klj!2cv$  
int nThreadID; //Thread's ID mwxJ#  
boolean bDownOver = false; //Downing is over 5|Qr"c$p  
boolean bStop = false; //Stop identical ]CjODa  
FileAccessI fileAccessI = null; //File Access interface
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException l}x{.q7Ul  
{ tR3hbL$W  
this.sURL = sURL; a$ }^z  
this.nStartPos = nStart; UWHC]V?  
this.nEndPos = nEnd; Hg4Ut/0  
nThreadID = id; @)B_e*6>'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "<n{/x(  
} DWAU8>c+  
@,]v'l!u  
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public void run() 4.8,&{w<m  
{ 0^=S:~G  
while(nStartPos < nEndPos && !bStop) #qWEyb2UZ  
{ 0:*$i(2  
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try{ S`::f(e  
URL url = new URL(sURL); 7j+.H/2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t%)L8%Jr  
httpConnection.setRequestProperty("User-Agent","NetFox"); vzL>ZBe
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String sProperty = "bytes="+nStartPos+"-"; kQ +   
httpConnection.setRequestProperty("RANGE",sProperty); ]zO]*d=m  
Utility.log(sProperty); g!$ "CX%8  
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InputStream input = httpConnection.getInputStream(); UxW~

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//logResponseHead(httpConnection); 7?Fl [FW$  
;.Kzc3yz}  
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byte[] b = new byte[1024]; W6pS.}  
int nRead; jV(IS
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) B~^\jRd"  
{ ^JTfRZ:a  
nStartPos += fileAccessI.write(b,0,nRead); ?@~FT1"6G  
//if(nThreadID == 1) f*Kipgp  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {1o=/&  
} }V 1sY^C  
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Utility.log("Thread " + nThreadID + " is over!"); -I -wdyDr  
bDownOver = true; -$7Jc=:>  
//nPos = fileAccessI.write (b,0,nRead); /<mc~S7  
} \sk,3b
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catch(Exception e){e.printStackTrace ();} ]C!u~A\jq  
} 1yhx)m;f  
} E_
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^C(AMT  
//打印回应的头信息 _7Z$"  
public void logResponseHead(HttpURLConnection con) L8V'mUyD  
{ CTwP{[%Pk  
for(int i=1;;i++) KT3[{lr  
{ `]%{0 Rx  
String header=con.getHeaderFieldKey(i); @y,p-##e  
if(header!=null) '!_o`t@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ,yB-jk?  
Utility.log(header+" : "+con.getHeaderField(header)); D!:Qy@Zw  
else bc+'n  
break; hJ|z8Sy@1  
} TqWvHZX  
} \UXQy{Ex  
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public void splitterStop() 3LEN~N}  
{ (F @IUbnl  
bStop = true;
8}U/fQ~  
} ^0r@",  

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} YXmLd'F^3  
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/* `aCcTs7~]p  
**FileAccess.java Q[}mH: w  
*//文件访问(定位，写) rIu>JyC"p  
package NetFox; \\[P^ tsF  
import java.io.*; Ar|_UV>Zf  
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public class FileAccessI implements Serializable{ [9w8oNg0  
l!`m}$  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 c0tv!PSw  
RandomAccessFile oSavedFile; uz%rWN`{  
long nPos; &)rm
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public FileAccessI() throws IOException b+w|3bQa  
{ 5Eq_L  
this("",0); \wTWhr0  
}  HSTtDTo  
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public FileAccessI(String sName,long nPos) throws IOException 9X!OQxmg  
{ J H6\;G6  
oSavedFile = new RandomAccessFile(sName,"rw"); P,,@&* :  
this.nPos = nPos; d=q2Or   
oSavedFile.seek(nPos); 6Z7{|B5}Y  
} :g][99  
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public synchronized int write(byte[] b,int nStart,int nLen)
lx%<oC+M  
{ d kPfdK}G  
int n = -1; *`|F?wF  
try{ XWK A0  
oSavedFile.write(b,nStart,nLen); 1,Y-_e)  
n = nLen; n`}vcVL;  
} kGCd!$fsk  
catch(IOException e) hMi`n6m  
{ ZU/6#pb  
e.printStackTrace (); e5MX5 T^  
} g&v2=&aj  
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return n; Dk/;`sXV  
} 7v#sr<  
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} zxXm9zrLo  
) _"`
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/* )~rN{W<s`H  
**SiteInfoBean.java GBN^ *I  
*/ ~fEgrF d  
package NetFox; c}lUP(Ss  
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public class SiteInfoBean { @99@do|C  
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private String sSiteURL; //Site's URL `5Q0U%`W  
private String sFilePath; //Saved File's Path {Dqf.w>t  
private String sFileName; //Saved File's Name N_Yop  
private int nSplitter; //Count of Splited Downloading File sFMSH:5z  
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/qEoiL###  
public SiteInfoBean() A@+pv
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{//nSplitter的缺省值为5 .XTBy/(0  
//default value of nSplitter is 5 ?~hC.5  
this("","","",5); JuS#p5E #  
} u1(`^^Ml  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) an=8['X  
{ ~[t%g9  
sSiteURL= sURL; 3`$-  
sFilePath = sPath; K'Wg_ihA  
sFileName = sName; p
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this.nSplitter = nSpiltter; *ax$R6a#X  
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c&J,O1){\  
} 44b;]htv  
{IJ,y27  
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public String getSSiteURL() 8 YsDE_  
{ wHvX|GwMv  
return sSiteURL; V`m'r+ Y  
} =Z2Cg{z  
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4DaLmQ2O  
public void setSSiteURL(String value) 9])dLL0  
{ V)
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sSiteURL = value; *xI0hFJIM  
} GMyzQ]@}  
e3}`]  
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public String getSFilePath() :'|%~&J  
{ F$F,I,$ "  
return sFilePath; ?I6!m~  
} \ym3YwP4/:  
4f:B2x{
 
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public void setSFilePath(String value) 
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{ V)
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sFilePath = value; Vf:/Kokq  
} 1Ue)&RW  
:q/%uca9  
DY/xBwIF  
public String getSFileName() a6cq0g[#z  
{ T%B&HsH  
return sFileName; #`?B
:  
} 7VduewKX8  
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#?DwOUw  
public void setSFileName(String value) bz<f u  
{ t2uX+1F  
sFileName = value; ).0klwfV  
} B+
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| vL0}e  
public int getNSplitter() jgNdcP  
{ 8lk@ev=O&  
return nSplitter; uxLT*,  
} #eadkj#;  
"
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589hfET  
public void setNSplitter(int nCount) ^YiGvZJ  
{ z3x/Y/X$S  
nSplitter = nCount; !tJQ75Hwv  
} 7uQiP&v  
} N@6+DH
t  
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/* j1D 1tn  
**Utility.java @K
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*/ EIQ`?8KSR  
package NetFox; ^,O%E;g^#  
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public class Utility { RC?gozBFJ  
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public Utility() pZ
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{ >J(._K  
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} GWd71ZtFO  
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//线程睡眠 ^m pWQ`R  
public static void sleep(int nSecond) &GYnGrw?@  
{ %x{jmZ$}  
try{ o_ng{SL  
Thread.sleep(nSecond); 6)=`&>9  
} -@bOFClE  
catch(Exception e) -4wr)zjfW  
{ lidVe]>  
e.printStackTrace (); FJ-X~^  
} +;,65j+n   
} AwnQ5-IR\  
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//日志 P! cfe@;<4  
public static void log(String sMsg) t?1b(o
J  
{ [h&)h+xt  
System.err.println(sMsg); ^cRAtoa  
} ,i RUR8  
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%Yw?!GvL[  
public static void log(int sMsg) U/ds(*g@  
{ gug9cmA/Q7  
System.err.println(sMsg); _\&vA5-  
} NW]zMU{c  
} 'k'"+  
t?Ku6Z'  
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/* 1FA:"0lO  
**TestMethod.java (}B3df  
*/ E)>.2{]C>  
package NetFox; okm }%#|  
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public class TestMethod { B<$(
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~#MXhhqB  
6+UTEw;  
public TestMethod() ^=Dz)95c  
{ ///xx/weblogic60b2_win.exe LO;7NK  
try{ m+|yk.md  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); k%D|17I  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); gUr#3#  
SiteFileFetch fileFetch = new SiteFileFetch(bean); H~$*R7~  
fileFetch.start(); ,tTq25~H\  
} Efp[K}Z^$  
catch(Exception e){e.printStackTrace ();} 56JxHQu  
8&Md=ZvK`  
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} i2P:I A|@  
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public static void main(String[] args) '[Zgwz;z  
{ L}=DC =E  
new TestMethod(); ;~,)6UX7  
} rSa=NpFxLu  
} gWD46+A){  
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