http断点续传简单实现（java)

/* $2=-Q/lM  
**SiteFileFetch.java A`|OPi)  
*/ |0vV?f$  
package NetFox; m"P"iK/Av(  
import java.io.*; -z]v"gF?Px  
import java.net.*; I^pD=1Y]  
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public class SiteFileFetch extends Thread { _C3l2v'I$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean S&jZYq**  
long[] nStartPos; //开始位置 x j6-~<  
long[] nEndPos; //结束位置 I4kN4*d!N,  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 wV- kB4^4
 
long nFileLength; //文件长度 lPL>8.j  
boolean bFirst = true; //是否第一次取文件 6$qn'K$  
boolean bStop = false; //停止标志 c0v;r4Jo#j  
File tmpFile; //文件下载的临时信息 okx~F9  
DataOutputStream output; //输出到文件的输出流 Qo>VN`v  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Z `FqC  
public SiteFileFetch(SiteInfoBean bean) throws IOException \h
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{ ZzA4iT=KO  
siteInfoBean = bean; UxZT&x3=)}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); md_9bq/w  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5I,5da  
if(tmpFile.exists ()) ;EZ$8|  
{ P+!j[X^  
bFirst = false; Fj<#*2{]B  
read_nPos(); SV;S`\i  
} Fw!CssW  
else &]gw[ `  
{ >'3J. FY  
nStartPos = new long[bean.getNSplitter()]; "f|\":\  
nEndPos = new long[bean.getNSplitter()]; qP<wf=wY  
} 3-4' x2   
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} pj.}VF!d  
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public void run() s^Lg*t3I  
{ vz
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//获得文件长度 f8um.Xnp6  
//分割文件 c`w
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//实例FileSplitterFetch N
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//启动FileSplitterFetch线程 zCxr]md  
//等待子线程返回 8 ;oU{  
try{ '&{`^l/MH  
if(bFirst) Pl4$`Qw#y  
{ ..RCR_DIp  
nFileLength = getFileSize(); Op^r}7
 
if(nFileLength == -1) XPnN"Y"y  
{ ;`IZ&m$  
System.err.println("File Length is not known!"); DDh$n?2fd  
} YK Nz[x$|  
else if(nFileLength == -2) {Muw4DV  
{ dx{ZG'@aH  
System.err.println("File is not access!"); A;E7~qOG  
} A<esMDX  
else N<V,5  
{ bgs2~50  
for(int i=0;i<nStartPos.length;i++) I9GRSm;0<  
{ ajFSbi)l  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); V_*TY6  
} S EdNH.|I  
for(int i=0;i<nEndPos.length-1;i++) o<T_Pjp  
{ g:bw;6^u  
nEndPos = nStartPos[i+1]; ln}2  
} _bp9UJ  
nEndPos[nEndPos.length-1] = nFileLength; ,<]X0;~oB  
} `* !t<?$i  
} S7SD$+fX  
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//启动子线程 /8 /2#`3R  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; z Qtg]@S  
for(int i=0;i<nStartPos.length;i++) u'"VbW3u n  
{ Z3Le?cMt^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B=K&+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !Oj]. WQ  
nStartPos,nEndPos,i); G5~ Jp#uA  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Z~O1$,Z  
fileSplitterFetch.start(); P)he3  
} z)$X/v  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }r`m(z$z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Ys|n9pW  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Ic_>[E?k  
nEndPos = " + nFileLength); 0&!,+  
// fileSplitterFetch[nPos.length-1].start(); Ik_u34U  
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//等待子线程结束 uzA"+cV5  
//int count = 0; (gd+-o4  
//是否结束while循环 l_ /q/8-l  
boolean breakWhile = false; Ra%" +=  
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while(!bStop) R{zAs?j  
{ Hk)IV"[R  
write_nPos(); md8r"  
Utility.sleep(500); `/en&l  
breakWhile = true; biZwxP3  
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for(int i=0;i<nStartPos.length;i++) FM\yf]'  
{ @"[xX}xK;  
if(!fileSplitterFetch.bDownOver) yEm[C(gZ  
{ L~nVoKY*V  
breakWhile = false; *m_B#~4  
break; 1&_93  
} vMBF7Jfx  
} [gK (x%  
if(breakWhile) C(( 7  
break; ,dhSc<:LT  
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//count++; +S!gS|8P  
//if(count>4) 6|q\ M  
// siteStop(); {Vy2uow0  
} &p>VTD  
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System.err.println("文件下载结束！"); :q6j{C(
 
} 3<:(Eda}  
catch(Exception e){e.printStackTrace ();} FbxrBM  
} e
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//获得文件长度 ^HpUbZpat)  
public long getFileSize() 2)O-EAn  
{ JO*}\
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int nFileLength = -1; S
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try{ ;|(_;d  
URL url = new URL(siteInfoBean.getSSiteURL()); RzPqtN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~j}7Fre  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^Fmp"[q  
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int responseCode=httpConnection.getResponseCode(); 
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if(responseCode>=400) ["N{6d&Q  
{ 
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processErrorCode(responseCode); U-uBz4Gha  
return -2; //-2 represent access is error R
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} XE/K|o^Hp  
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String sHeader; lPA:aHcj  
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for(int i=1;;i++) nJEm&"AI  
{ IhIPy~Hgt  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~N2<-~=si  
//Utility.log(in.readLine()); tS1(.CRk  
sHeader=httpConnection.getHeaderFieldKey(i); #=>t6B4af  
if(sHeader!=null) \\\%pBT7]\  
{ @qC](5|TQ  
if(sHeader.equals("Content-Length")) *{}Y :  
{ {yPJYF
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Xi^#F;@sU  
break; %<4ZU!2L  
} HzdtR  
}
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else *|Cmm>z"7  
break; %XIPPEHU  
} !1g2'  
} hrLPyV:  
catch(IOException e){e.printStackTrace ();} l$j/Ye]  
catch(Exception e){e.printStackTrace ();}  3+[R
!  
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Utility.log(nFileLength); )U>JFgpI
W  
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return nFileLength; ^U[c:Rz  
} ;cye 'E  
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//保存下载信息（文件指针位置） hB]\vA7  
private void write_nPos() ]!v:xjzT  
{ Sdk:-Zuv  
try{ F;I %9-R  
output = new DataOutputStream(new FileOutputStream(tmpFile)); _{d0Nm  
output.writeInt(nStartPos.length); /hNZ7\|P  
for(int i=0;i<nStartPos.length;i++) x)+3SdH  
{ _[eAA4h   
// output.writeLong(nPos); y":Y$v,P  
output.writeLong(fileSplitterFetch.nStartPos); !|SVRaS  
output.writeLong(fileSplitterFetch.nEndPos); R~=_,JUW  
} @k"Q e&BQ  
output.close(); nPAVrDg O  
} h3}gg@Fm  
catch(IOException e){e.printStackTrace ();} z2EZ0vZ  
catch(Exception e){e.printStackTrace ();} ( !K?^si  
} 
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//读取保存的下载信息（文件指针位置） F4Jc7k2  
private void read_nPos() n0/H2>I[  
{ R]s\s[B  
try{ 0`{3|g  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); qUZm6)p6[a  
int nCount = input.readInt(); Y?1 3_~ K  
nStartPos = new long[nCount]; c^4^z"Mo`  
nEndPos = new long[nCount]; qHAZ)Tz  
for(int i=0;i<nStartPos.length;i++) (wMiXi  
{ fV 6$YCf  
nStartPos = input.readLong(); R{GT? wl  
nEndPos = input.readLong(); FEdWe\E  
} `oDs]90  
input.close(); H(MCY3t  
} x]1G u  
catch(IOException e){e.printStackTrace ();} BdK2I!mm  
catch(Exception e){e.printStackTrace ();} $r>\y (W  
} MS_@ Xe  
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private void processErrorCode(int nErrorCode) |=dmxfj@  
{ "0,d)L0,"  
System.err.println("Error Code : " + nErrorCode); c h_1-  
} `|Ll  
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//停止文件下载 u-31$z<<5}  
public void siteStop() Ps0g  
{ j.'Rm%@u  
bStop = true; N
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for(int i=0;i<nStartPos.length;i++) sSh=Idrx  
fileSplitterFetch.splitterStop(); r`; "  
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} T:/68b*H\:  
} &_DRrp0CN  
//负责部分文件的抓取 ~JU :a@)  
**FileSplitterFetch.java l7.W2mg
 
*/ x[ sSM:  
package NetFox; L>,j*a_[  
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import java.io.*; z_Nw%V4kr  
import java.net.*; f;Iaf#V_  
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public class FileSplitterFetch extends Thread { c]pO'6]  
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String sURL; //File URL V4('}Q!  
long nStartPos; //File Snippet Start Position :sMc}k?9S  
long nEndPos; //File Snippet End Position -:5]*zVp+-  
int nThreadID; //Thread's ID K3c(c%$<R  
boolean bDownOver = false; //Downing is over \Oku<5  
boolean bStop = false; //Stop identical :%#(<@{  
FileAccessI fileAccessI = null; //File Access interface @.4e^Km  
a ]PS`  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException NwK(<dzG  
{ xJ;DkPh  
this.sURL = sURL; WIe2j  
this.nStartPos = nStart; GM5s~,  
this.nEndPos = nEnd; wbC'SOM  
nThreadID = id; [M^ur%H  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 w Wx,}=  
} 9Q!X~L|\S  
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public void run() \Z +O9T%  
{ lS`hJ:  
while(nStartPos < nEndPos && !bStop) ;'\{T#5)  
{ E&?z-,-o@  
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try{ 7VP[U,  
URL url = new URL(sURL); Lv;R8^n  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `.0QY<;  
httpConnection.setRequestProperty("User-Agent","NetFox"); t^|+|>S  
String sProperty = "bytes="+nStartPos+"-";  c`'2  
httpConnection.setRequestProperty("RANGE",sProperty); {y{&tzZ  
Utility.log(sProperty); 0FDfB;  
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InputStream input = httpConnection.getInputStream(); ODGOWw0  
//logResponseHead(httpConnection); Ax#$z  
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byte[] b = new byte[1024]; 5"f')MKUV9  
int nRead; 1 :xN)M,s  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) YpFh_Zr[  
{ |eEcEu?/b  
nStartPos += fileAccessI.write(b,0,nRead); 0NY2Kw;  
//if(nThreadID == 1) xh7#\m_U8  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 49o5"M(  
} NqsIMCl  
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Utility.log("Thread " + nThreadID + " is over!"); 0Ey*ci^ue  
bDownOver = true; 8:j8>K*6  
//nPos = fileAccessI.write (b,0,nRead); * /S=9n0  
} 2 {lo  
catch(Exception e){e.printStackTrace ();} ^]He]FW':G  
} OzFA>FK0f;  
} ~E2xIhV  
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//打印回应的头信息 J$)lYSNE  
public void logResponseHead(HttpURLConnection con) Qrt[MJ+#  
{ 5feCA ,v7  
for(int i=1;;i++) -[kbHrl&  
{ ,UFr??ZKm  
String header=con.getHeaderFieldKey(i); \R>!HY  
if(header!=null) ?#F}mOVAa  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )'{:4MX  
Utility.log(header+" : "+con.getHeaderField(header)); @u.
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else +DwyMzeE  
break; Z8??+d=  
} ^(p}hSLAfQ  
} pKrol]cth8  
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public void splitterStop() 4Fr0/="H  
{ \lVX~r4  
bStop = true; |V2+
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} x\vb@!BZ  
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o@}+b}R}  
} X0X!:gX  
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/* v*Qr(4  
**FileAccess.java SSANt?\Z<  
*//文件访问(定位，写) v%|()Z0  
package NetFox; 28L3"c  
import java.io.*; RHo|&.B;+  
|qS<{WZ!h  
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public class FileAccessI implements Serializable{ )1H$5h  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 /8baJ+D"4\  
RandomAccessFile oSavedFile; 36D-J)-Z  
long nPos; ;b:Ct<  
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public FileAccessI() throws IOException 1!. CfQi  
{ t@-:e^ v  
this("",0); S5ofe]tS@  
} T!o 4k  
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public FileAccessI(String sName,long nPos) throws IOException <,,U>0?3  
{ 5fS89?/?  
oSavedFile = new RandomAccessFile(sName,"rw"); .}.5|z} A  
this.nPos = nPos; B[^mWVp6L  
oSavedFile.seek(nPos); 8Z>ZjNG  
} fG O.wb  
7>EjP&l  
e
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public synchronized int write(byte[] b,int nStart,int nLen) ( q^umw  
{ }et^'BkA(  
int n = -1; hQrO8T?2  
try{ z#b31;A@$  
oSavedFile.write(b,nStart,nLen); zH8l-0I+$  
n = nLen; ;pdW7  
} :Vq gmn  
catch(IOException e) CqDMq!  
{ 93:s[bmx  
e.printStackTrace (); w}pFa76rm  
} @=)_P
G  
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return n; z%t>z9hU  
} Dm6WSp1|b  
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} tsq]QTA*  
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/* ^lB'7#7  
**SiteInfoBean.java ]t]s/;9]K  
*/ ;ej;<7+  
package NetFox; YD$fN"}-  
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public class SiteInfoBean { hRSRz5 J}  
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private String sSiteURL; //Site's URL {$4fRxj  
private String sFilePath; //Saved File's Path Z2`(UbG}  
private String sFileName; //Saved File's Name SZH,I&8  
private int nSplitter; //Count of Splited Downloading File Fsv%=E{  
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public SiteInfoBean() WcAX/<Y>  
{//nSplitter的缺省值为5 U$6N-q  
//default value of nSplitter is 5 /og2+!  
this("","","",5); mYXe0E#6  
} '~%1p_0dq  
fZH:&EP  
95>(NwST4  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >F6'^9|  
{ bl(rCbj(w  
sSiteURL= sURL; %7pT\8E5  
sFilePath = sPath; =:mD)oX*  
sFileName = sName; eiI}:5~ /g  
this.nSplitter = nSpiltter; XKLkJZN  
[F%INl-sy  
GUE3|  
} bNp RGhlV  
"zL<:TQ"  
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public String getSSiteURL() 8-UlbO6  
{ ^tIs57!  
return sSiteURL; ko*Ir@SDv  
} DzYi> E:*  
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m^@,0\F  
public void setSSiteURL(String value) )t{?7wy  
{ E$=!l{Ms  
sSiteURL = value; )8p FPr  
} *KN'0Z@W  
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M%5qx,JQY  
public String getSFilePath() T?{"T/  
{ c#|!^gjf  
return sFilePath; g"c\ouSY  
} q+5g+9  
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public void setSFilePath(String value) thIuK V{CO  
{ b/HhGA0  
sFilePath = value; !E8y!|7$  
} Lqq RuKi  
zs:OHEZw  
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public String getSFileName() +Kg
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{ b^_#f:_j
 
return sFileName; .w/w] Eq  
} X|fl_4NC>  
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public void setSFileName(String value) E58fY|9  
{ j\k|5="w-  
sFileName = value; uP2e/a  
} g|ewc'y  
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public int getNSplitter() _b|mSo,{Y  
{ 4v9jGwnzt  
return nSplitter; WyciIO1  
} EK`}?>'  
U27YH1OK  
-d5b,leC^  
public void setNSplitter(int nCount) l*~O;do  
{ 'Dw+k;RH  
nSplitter = nCount; `u6CuH
5  
} |`vwykhezO  
} nX%b@cOXj  
3}R}|Ha J#  
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/* )tYu3*'  
**Utility.java !*Ex}K99  
*/ yTJ Eo\g/@  
package NetFox; QL/I/EgqC  
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public class Utility { jHjap:i`cI  
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public Utility() )&/ecx"
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{ $O nh2 ^  
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}
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//线程睡眠 \jA#RF.W  
public static void sleep(int nSecond) @vyq?H$U;N  
{ 7pPaHX8  
try{ suKr//_  
Thread.sleep(nSecond); OHRkhwF.  
} LH}]& >F  
catch(Exception e) CcCcuxtR  
{ @!'rsPrI  
e.printStackTrace ();  iYaS  
} `:b*#@  
} KC+jHk  
Nyx)&T&I  
//日志 i,
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public static void log(String sMsg) ^(F@#zN}  
{ HQkK8'\LP  
System.err.println(sMsg); r7ebFJEf  
} XoNBq9Iu  
~a$h\F'6  
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l  
public static void log(int sMsg) <aQ<Wy=\  
{ G!T_X*^q2U  
System.err.println(sMsg); /7N&4FrG  
} 7Is:hx|:  
} &J?:wC=E  
LvqWA}  
Y_zMj`HE  
/* dtj+ avG  
**TestMethod.java H\fsyxM7  
*/ ;\g0*b(  
package NetFox; i 558&:  
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public class TestMethod { $GR rTC!  
9-+N;g!q  
\ )WS^KR%  
public TestMethod() ^c<8|lK L@  
{ ///xx/weblogic60b2_win.exe uv=a}U;  
try{ 5OCt Q4u  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); a]/KJn/B(  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [ $5u:*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); q|{
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fileFetch.start(); {'p < o$(S  
} xa'^:H $X  
catch(Exception e){e.printStackTrace ();} ff;~k?L  
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} 5sANF9o!  
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x2sKj"2?@  
public static void main(String[] args) -=cm7/X  
{ ;W T<]  
new TestMethod(); -{}
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} eBH:_Ls_-^  
} i)$P1h
 
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