http断点续传简单实现（java)

/* te-xhJ&K  
**SiteFileFetch.java !>> A@3  
*/ .ZF%$H  
package NetFox; \{:A&X~\!  
import java.io.*; jDb\4QyC  
import java.net.*; 7WS$fUBi  
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public class SiteFileFetch extends Thread { tt?`,G.(]  
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SiteInfoBean siteInfoBean = null; //文件信息Bean JS^DyBXc  
long[] nStartPos; //开始位置 G`O*A
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long[] nEndPos; //结束位置 rP7 QW)NF  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 c86KDEF  
long nFileLength; //文件长度 uq s   
boolean bFirst = true; //是否第一次取文件 !'^l}K>  
boolean bStop = false; //停止标志 4jebx jZ  
File tmpFile; //文件下载的临时信息 k-=lt\?  
DataOutputStream output; //输出到文件的输出流 6R<+_e+v  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 
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public SiteFileFetch(SiteInfoBean bean) throws IOException ~:7y!=8#  
{ A)"L+Yu5  
siteInfoBean = bean; Dh2Cj-| ~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); U52V1b  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); z~vcwiYAP  
if(tmpFile.exists ()) GWuKDq  
{ G)I` M4}*n  
bFirst = false; }6-olVg  
read_nPos(); m8
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} N s0,Z#Z+  
else ,H+Y1N4W(  
{ U[x$QG6m!  
nStartPos = new long[bean.getNSplitter()]; mN]WjfII  
nEndPos = new long[bean.getNSplitter()]; XN Uw  
} tdxzs_V,-
 
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}  Jk(V ]  
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public void run() a
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{ AH&RabH2  
//获得文件长度 uthW AT &  
//分割文件 AE~a=e\x  
//实例FileSplitterFetch i8e*9;4@  
//启动FileSplitterFetch线程 T{Xd>  
//等待子线程返回 P1rjF:x[*  
try{ Pz0Ma
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if(bFirst) 2kVZlt'y  
{ P'tXG  
nFileLength = getFileSize(); \DujF>:  
if(nFileLength == -1) UU>+b:  
{ tNr'@ls  
System.err.println("File Length is not known!"); cdL]s^z  
} /g+-{+sx  
else if(nFileLength == -2) U$gR}8\e  
{ o|h=M/  
System.err.println("File is not access!"); oFP8s[B  
} ugTsI~aE  
else (+(@P*c1  
{ ?ld&}|W~  
for(int i=0;i<nStartPos.length;i++) YT+b{   
{ a
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); >"!ScYn  
} 0}e?hbF%U  
for(int i=0;i<nEndPos.length-1;i++) /.7RWy`  
{ Pp!4Ak4TT9  
nEndPos = nStartPos[i+1]; ZtO$kK%q;  
} 8k-]u3  
nEndPos[nEndPos.length-1] = nFileLength; e7"T37  
} X$6NJ(2G  
} 2T+-[}*  
e,}h^^"  
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//启动子线程 b;jdk w|  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $k0(iFzR1  
for(int i=0;i<nStartPos.length;i++) H;\C7w|  
{ q,)V0Ffe[|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V5Z
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), I9G^T' W  
nStartPos,nEndPos,i); tIDN~[1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  :2nsi4  
fileSplitterFetch.start(); $T3_~7N  
} xgcJEox!  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !i-t6f  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); LcvczST  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", C`_/aR6  
nEndPos = " + nFileLength); 9F[3B`w  
// fileSplitterFetch[nPos.length-1].start(); Hh;l
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*tj(,:!  
//等待子线程结束 I{dy,\p  
//int count = 0; j36YIz$a  
//是否结束while循环  cX C[O  
boolean breakWhile = false; GgY8\>u  
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while(!bStop) c|.te]!ds  
{ rmA?Xlh\  
write_nPos(); d*{Cv2A.  
Utility.sleep(500); <!RkkU& 6  
breakWhile = true; Qb?a[[3  
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for(int i=0;i<nStartPos.length;i++) N8Rq7i3F?a  
{ FtyT:=Kpc  
if(!fileSplitterFetch.bDownOver) N2s"$Ttq  
{ mM&P&mz/D  
breakWhile = false; :a/rwZ[r  
break; 13F]7l-#  
} @Nsn0-B?ne  
} (n7xYGfYS  
if(breakWhile) 8%B_nVc  
break; 9R8q+2  
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//count++; r]cq|Nv8:  
//if(count>4) d)-ZL*o  
// siteStop(); E{ c+`>CY  
} HL"c yxe  
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System.err.println("文件下载结束！"); JR]elRR  
} $7AsMlq[(  
catch(Exception e){e.printStackTrace ();} :'Gn?dv|  
}
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//获得文件长度 :1qLRr  
public long getFileSize() K!CVS7  
{ 5B:"$vC{=  
int nFileLength = -1; 3v_j*wy  
try{ /Q@4HV  
URL url = new URL(siteInfoBean.getSSiteURL()); eG(YORkR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /~'C!so[v  
httpConnection.setRequestProperty("User-Agent","NetFox"); r~T!$Tb  
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int responseCode=httpConnection.getResponseCode(); ]'xci"qV`  
if(responseCode>=400) gBV4IQ  
{ GEy7Vb)  
processErrorCode(responseCode); %!Eh9C*  
return -2; //-2 represent access is error \wz^Z{U  
} IQ\!wWKmY  
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String sHeader; iWjNK"W  
'Iw`+=iVz  
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for(int i=1;;i++) A<c<!N  
{ ktqFgU#rT  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); JmCHwyUK?  
//Utility.log(in.readLine()); ?0X$ox  
sHeader=httpConnection.getHeaderFieldKey(i); @Un/,-ck  
if(sHeader!=null) UeCi{W  
{ [/hoNCH!  
if(sHeader.equals("Content-Length")) zu?112-v2  
{ -x6_HibbD  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [x7Rq_^  
break; gnN>Rl 5_  
} !
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} NqF*hat  
else KtAEM;g  
break; *bpN!2  
} moFrNcso  
} Jk}3c>^D  
catch(IOException e){e.printStackTrace ();} ?&:N|cltD  
catch(Exception e){e.printStackTrace ();} I\1E=6"  
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Utility.log(nFileLength); -n"f>c_{>  
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return nFileLength; 
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} R-pON4D"*  
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//保存下载信息（文件指针位置） zZ-/S~l  
private void write_nPos() aO1.9!<v  
{ 8HLL3H0  
try{ T$M
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output = new DataOutputStream(new FileOutputStream(tmpFile)); OcF_x/#  
output.writeInt(nStartPos.length); |g{50r'=  
for(int i=0;i<nStartPos.length;i++) J ##a;6@  
{ Y_]y :H  
// output.writeLong(nPos); h
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output.writeLong(fileSplitterFetch.nStartPos); 5KB Z-,  
output.writeLong(fileSplitterFetch.nEndPos); nWCJY:q;5  
} /z^v%l  
output.close(); th*
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} vh2/d.MO  
catch(IOException e){e.printStackTrace ();} Yqh-U%"'  
catch(Exception e){e.printStackTrace ();} :I?lT2+ea  
} *j(fk[,i  
,DHH5sDCn  
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//读取保存的下载信息（文件指针位置） ;FwUUKj  
private void read_nPos() CaCApL  
{ `Qb!W45  
try{ )2EvZn  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;/Y#ph[  
int nCount = input.readInt(); kygj" @EX  
nStartPos = new long[nCount]; T@vE@D  
nEndPos = new long[nCount]; B7C<;`5TiD  
for(int i=0;i<nStartPos.length;i++) ?8grK  
{ :twp95{R1  
nStartPos = input.readLong(); ^0_>  
nEndPos = input.readLong(); p\~ a=  
} )ty>{t  
input.close(); h{HpI 0q4  
} k:/Z6TLk3  
catch(IOException e){e.printStackTrace ();} h;E.y   
catch(Exception e){e.printStackTrace ();} 76[qFz  
} o}waJN`yI  
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private void processErrorCode(int nErrorCode) nY;Sk#9  
{ 5<GeAW8ns]  
System.err.println("Error Code : " + nErrorCode); O '#FVZ.g  
} ,%/F,O+#  
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//停止文件下载 +{6:]  
public void siteStop()  1l}Am>}  
{ p{qA%D  
bStop = true; @CR<&^s5V  
for(int i=0;i<nStartPos.length;i++) ?:GrM!kq76  
fileSplitterFetch.splitterStop(); -*&aE~Cs  
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} XOS^&;  
} n~>b}DY  
//负责部分文件的抓取 U\{I09@E 0  
**FileSplitterFetch.java 0:`YY8j1k  
*/ es69P)  
package NetFox; "E5=AWd  
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import java.io.*; #EKnjh=Uq  
import java.net.*; e=j
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public class FileSplitterFetch extends Thread { C_[
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String sURL; //File URL ze+S_{  
long nStartPos; //File Snippet Start Position #\="^z6  
long nEndPos; //File Snippet End Position lzFg(Ds!f  
int nThreadID; //Thread's ID }
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boolean bDownOver = false; //Downing is over V~.SgbLc  
boolean bStop = false; //Stop identical \Ym$to  
FileAccessI fileAccessI = null; //File Access interface 0^2e^qf  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException f~jdN~  
{ s!Id55R]  
this.sURL = sURL; 3!?QQT,!)  
this.nStartPos = nStart; x)q$.u+  
this.nEndPos = nEnd; ](ztb)  
nThreadID = id; Mns=X)/hc  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 E[CvxVCx  
} KJ-Q$ M  
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public void run() N'5DB[:c:  
{ RzB64  
while(nStartPos < nEndPos && !bStop) *:l$ud  
{ #s}tH$MT#  
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try{ &t@ $]m(  
URL url = new URL(sURL); eEmLl(Lb  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -42 U  
httpConnection.setRequestProperty("User-Agent","NetFox"); !P6y_Frpe  
String sProperty = "bytes="+nStartPos+"-"; ri9n.-xs  
httpConnection.setRequestProperty("RANGE",sProperty); Eh`W J~  
Utility.log(sProperty); M9yqJPS}B  
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InputStream input = httpConnection.getInputStream(); ws]d,]  
//logResponseHead(httpConnection); BIvz55g  
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byte[] b = new byte[1024]; 127@ TN"  
int nRead; QX-M'ur99  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ~vR<UQz  
{ ;ZrFy=Iv  
nStartPos += fileAccessI.write(b,0,nRead); 5kv]k?   
//if(nThreadID == 1) (ub
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P_@ty~u  
} M?$tHA~OX  
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.9!&x0;  
Utility.log("Thread " + nThreadID + " is over!"); *EtC4sP  
bDownOver = true; Gg7ZSB 7  
//nPos = fileAccessI.write (b,0,nRead); aUBu"P$J  
} `\-MpNw  
catch(Exception e){e.printStackTrace ();} 6z67%U*8r  
} KkHlMw
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} 1[dQVJqMp(  
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//打印回应的头信息 
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public void logResponseHead(HttpURLConnection con) tki
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{ _..5G7%#%  
for(int i=1;;i++) l?beqw:  
{ Cmj `WSSa  
String header=con.getHeaderFieldKey(i); 'ka"0~:NS{  
if(header!=null) z<<aT  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); fli7Ow?M~  
Utility.log(header+" : "+con.getHeaderField(header)); l}Vg;"1'J  
else gE!`9#..  
break; |VoYFoiQ  
} =u&NdMy  
} W!Rr_'yFe)  
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public void splitterStop() 0k|/]zfb  
{ *;(GL  
bStop = true; v\COl*  
} xm<sH!,j  
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} 5z:/d`P[  
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/* Yf^/YLLS  
**FileAccess.java O[')[uo8s  
*//文件访问(定位，写) gq?~*4H  
package NetFox; >z8y L+  
import java.io.*; }(if|skau  
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public class FileAccessI implements Serializable{ C;!h4l7L  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <Xj ,>2m;  
RandomAccessFile oSavedFile; AqP\g k  
long nPos; l_*:StyR+  
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public FileAccessI() throws IOException s}Sxl0  
{ x1*@PiO,.  
this("",0); Z{.L_]$I  
} \U'TL_Ql  
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public FileAccessI(String sName,long nPos) throws IOException }\\6"90g*  
{ T]J#>LBd  
oSavedFile = new RandomAccessFile(sName,"rw"); zzBqb\Ky  
this.nPos = nPos; JYWc3o6  
oSavedFile.seek(nPos); A,#hYi=-,  
} zn{[]J  
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d
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public synchronized int write(byte[] b,int nStart,int nLen) ('pxX+  
{ pDx}~IB  
int n = -1; z'}?mE3i  
try{ p}swJ;S  
oSavedFile.write(b,nStart,nLen); NBZ>xp[U  
n = nLen; > 'KQL?!F  
} >pl*2M&  
catch(IOException e) h?:Y\DlU'  
{ _A/ ]m4  
e.printStackTrace (); k-vxKrjZ/  
} ;R?9|:7  
|tS~\_O/  
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return n; 4)nQBFX  
} @'!61'}f  
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} >taZ
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/* 5Gsj;  
**SiteInfoBean.java R OQIw  
*/ QcQ|,lA.HI  
package NetFox; ;EfMTI}6K  
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public class SiteInfoBean { 7u^6`P  
Gu_Rf&:  
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private String sSiteURL; //Site's URL !kfnqe?|  
private String sFilePath; //Saved File's Path [}_ar  
private String sFileName; //Saved File's Name 7e"(]NC84  
private int nSplitter; //Count of Splited Downloading File uQ.VW/>  
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public SiteInfoBean() Fk,3th  
{//nSplitter的缺省值为5 #B)`dA0a  
//default value of nSplitter is 5 tgYIM`f  
this("","","",5); l9.wMs*`X  
} ),6Z1 K1  
c$'Uf
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &WHEP
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{ 6%_d m'  
sSiteURL= sURL; 0\U28zbMJw  
sFilePath = sPath; 3^us;aOr  
sFileName = sName; qO9_e  
this.nSplitter = nSpiltter; <`9:hPp0  
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} h OboM3_  
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public String getSSiteURL() q+o(`N'~G  
{ MU&5&)m  
return sSiteURL; "v3u$-xN1  
} aV(*BE/@F  
q#Qr@Jf  
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public void setSSiteURL(String value) ^HL#)fK2I  
{ XfsCu>  
sSiteURL = value; X>|.BvY|  
} .[Sv|;x"E  
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public String getSFilePath() 1 )j%]zd2  
{ Z?hBn`.  
return sFilePath; 3G8uXB_`}  
} ._tv$Gd@k  
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public void setSFilePath(String value) $9DZ5"  
{ c/2OR#$t  
sFilePath = value; km<~Hw>Z  
} xHr  
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L6A6|+H%E  
public String getSFileName() sq)Nn&5A  
{ sX_^H%fd  
return sFileName; !P92e1  
} Cm;N5i  
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public void setSFileName(String value) m&A/IW,.  
{ |k+&weuY  
sFileName = value; T8hQ< \g  
} BkqIfV%O  
[bOy,^@4  
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public int getNSplitter() |_=jXf\TL  
{ zPk
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return nSplitter; !s)$_tG  
} 329xo03-[  
WAdl@){  
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public void setNSplitter(int nCount) v}Aw!Dv/  
{ G+g`=7  
nSplitter = nCount; Ixec]UOS  
} }5]s+m  
} .D>lv_kp  
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/* MK[spV  
**Utility.java =0]Mc$Ih  
*/ [ $"iO#oO  
package NetFox; /w!' [  
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public class Utility { ~!nd'{{9  
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 #b"IX`5  
public Utility() i ('EBO  
{ ?\pE#~m  
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} BxT~1SBFq  
!KlSw,&=.6  
//线程睡眠 x> q3w# B  
public static void sleep(int nSecond) 0Its;|  
{ +8Px` v1L  
try{ q7PRJX  
Thread.sleep(nSecond); aKUr":z  
} zg j35  
catch(Exception e) Ni)#tz_9  
{ Zn} )&Xt  
e.printStackTrace (); ]`kvq0Gyb  
} }n7e_qy4  
} i|O7nB@  
<&Uk!1Jd  
//日志 7w$R-Y/E  
public static void log(String sMsg) lKD@2  
{ Uy1xNb/d  
System.err.println(sMsg); [O)Zof  
} ;VH]TKkk  
<EUSl|6  
"PHv~_:^R  
public static void log(int sMsg) g|HrhUT;  
{ PmY:sJ{M  
System.err.println(sMsg); E9:hK  
} bOdv]nQ1  
} %Uk/P  
lG+ltCc$9  
qR<DQTO<  
/* $"(YE #]|  
**TestMethod.java }:8>>lQ  
*/ Q(IS=

 
package NetFox; D6oby*_w  
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c>
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public class TestMethod { -:>#w`H  
7EO&:b]  
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public TestMethod() q{ 1U  
{ ///xx/weblogic60b2_win.exe }\{1`$*~  
try{ vTEkh0Ys  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .%<&W1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); t5APD?5 c  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "3MUrIsB>  
fileFetch.start(); 4<K`yU]"  
} *4:/<wI!  
catch(Exception e){e.printStackTrace ();} xwxjj  
z{jAt6@7  
D5b_m|7%  
} ]."c4S_)|  
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kw~H%-,]  
public static void main(String[] args) $Ig,cTR.b  
{ S:uEK  
new TestMethod(); SkA'+(  
} XXcf!~uO  
} EXcjF  
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