http断点续传简单实现（java)

/* =VA5!-6<Uq  
**SiteFileFetch.java ,uz+/K%OA5  
*/ 117`=9F  
package NetFox; nsf.wHGZ"J  
import java.io.*; Nf@-i`  
import java.net.*; Ml-GAkgG  
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public class SiteFileFetch extends Thread { jLc"1+
 
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SiteInfoBean siteInfoBean = null; //文件信息Bean pI>yO~Ve  
long[] nStartPos; //开始位置 ^7b[spqE  
long[] nEndPos; //结束位置 $a /jfpV  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Oe#*-  
long nFileLength; //文件长度 H]]UsY`  
boolean bFirst = true; //是否第一次取文件 6?B'3~r  
boolean bStop = false; //停止标志 Z\1*g k  
File tmpFile; //文件下载的临时信息 *\gS 2[S  
DataOutputStream output; //输出到文件的输出流 [K5#4
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） A(Tqf.,G  
public SiteFileFetch(SiteInfoBean bean) throws IOException UQX.  
{ u/s,#  
siteInfoBean = bean; m!'moumL;  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); V1yY>  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); FCr^D$_w  
if(tmpFile.exists ()) dWR-}
>  
{ )># Y,/q  
bFirst = false; s)dL^lj;  
read_nPos(); 
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} +ConK>;  
else zcqv0lM '  
{ N~=,RPjq  
nStartPos = new long[bean.getNSplitter()]; DfPC@` k  
nEndPos = new long[bean.getNSplitter()]; iY~.U`b`  
} \`kH2`  
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} k vuSE  
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public void run() <2.87:  
{ z~m{'O`  
//获得文件长度 =/#+,  
//分割文件 a1Kh  
//实例FileSplitterFetch
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//启动FileSplitterFetch线程 8h?):e  
//等待子线程返回 1H-d<G0)  
try{ H{d;,KfX  
if(bFirst) qN=l$_UD  
{ ^ UDNp.6k  
nFileLength = getFileSize();  fOUW{s  
if(nFileLength == -1) -qJ%31Mr#  
{ :lfUVa{HN  
System.err.println("File Length is not known!"); QjIn0MJ)Xm  
} o9XT_!Cwg  
else if(nFileLength == -2) ! ^ DQX=1  
{ id?B<OM  
System.err.println("File is not access!"); h>a/3a$g  
} ~+)sL1lx  
else `w(~[`F t  
{ pYBY"r  
for(int i=0;i<nStartPos.length;i++) 2zPO3xL,  
{ !H^e$BA  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); x & ZW f?  
} @ L=dcO{r  
for(int i=0;i<nEndPos.length-1;i++) 3UNmUDl[~  
{ W1!Nq`  
nEndPos = nStartPos[i+1]; B)`@E4i  
} 'V`Hp$r  
nEndPos[nEndPos.length-1] = nFileLength;
+ FG Xx  
} !uc"|S?  
} xm*6I  
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//启动子线程 6>d0i S@R  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Hs#q 7  
for(int i=0;i<nStartPos.length;i++) W1\F-:4L@  
{ Ve9*>6i&-4  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \s@7pM=(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 84f~.45  
nStartPos,nEndPos,i); 0_f6Qrcj  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  N3m~nEj  
fileSplitterFetch.start(); "Nh}_jO  
} l\DcXgD x  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6V&HlJH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); K9=f`JI9  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Z[GeU>?P  
nEndPos = " + nFileLength); K?]c  
// fileSplitterFetch[nPos.length-1].start(); tPz!C&.=  
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//等待子线程结束 -RBH5+SS2  
//int count = 0; vwIP8z~<  
//是否结束while循环 +\s&v!  
boolean breakWhile = false; cKe{ ]a  
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while(!bStop) 1=Y pNXX  
{
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write_nPos(); =%ry-n G  
Utility.sleep(500); ,b'QL6>`  
breakWhile = true; *V[6ta
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for(int i=0;i<nStartPos.length;i++) 5~H}%W,P  
{ e"^n^_9  
if(!fileSplitterFetch.bDownOver) +A
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{ =g^k$ Rc  
breakWhile = false; oaGpqjBGQ  
break; c W^  
} !McRtxq?~  
} +2Wijrn  
if(breakWhile) Kq&JvY^  
break; %(d0`9  
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"LkI'>3}  
//count++; e;r?g67  
//if(count>4) "jA?s9  
// siteStop(); ,cwjieM  
}  .H7xG'$  
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System.err.println("文件下载结束！"); g"|/^G_6S  
} 4)z*Vux  
catch(Exception e){e.printStackTrace ();} 5169E*  
} #4wia%}u  
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//获得文件长度 f6U i~  
public long getFileSize() aF5=k:k  
{ vI5'npM  
int nFileLength = -1; Tp&7C
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try{ %C=?Xhnv  
URL url = new URL(siteInfoBean.getSSiteURL()); /PTk296@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .yN.  
httpConnection.setRequestProperty("User-Agent","NetFox"); Xb\de_8!  
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int responseCode=httpConnection.getResponseCode(); yl UkVr   
if(responseCode>=400) rw%1>]os  
{ Mx_
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processErrorCode(responseCode); JzZ@Z8%a;  
return -2; //-2 represent access is error {-.ZFUZmT  
} &!0%"4  
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String sHeader; .e1Yd8  
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for(int i=1;;i++) /A"UV\H`f  
{ W*.
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); s%Irh;Bs  
//Utility.log(in.readLine()); 344E4F"ph  
sHeader=httpConnection.getHeaderFieldKey(i); Fz1K*xx'  
if(sHeader!=null) 0.!!rq,  
{ \ ix&
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if(sHeader.equals("Content-Length")) ;^9y#muk  
{ 'FN+BvD  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); u~\l~v^mj  
break; @; 0t+  
} ~xakz BE  
} 1b`WzoJgH  
else L2`a| T=  
break; ^rssZQKY[  
} CI+@GXY  
} xG~7kj3  
catch(IOException e){e.printStackTrace ();} *z6m644H  
catch(Exception e){e.printStackTrace ();} 1 TA\6a}  
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Utility.log(nFileLength); B0dv_'L}L  
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return nFileLength; &T2qi'  
} }KFM8CbS  
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//保存下载信息（文件指针位置） *Vr;rk  
private void write_nPos() )Oix$B!-  
{ S?e*<s9k  
try{ 1rGi"kdf  
output = new DataOutputStream(new FileOutputStream(tmpFile)); bC0DzBnM;  
output.writeInt(nStartPos.length); i8i~b8r]  
for(int i=0;i<nStartPos.length;i++) qY$]^gS  
{ G[ gfD\  
// output.writeLong(nPos); U~s-'-C/  
output.writeLong(fileSplitterFetch.nStartPos); Jx
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output.writeLong(fileSplitterFetch.nEndPos); LypBS]ru  
} idSc#n22  
output.close(); NW`L
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} "
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catch(IOException e){e.printStackTrace ();} dZ%rmTE(H  
catch(Exception e){e.printStackTrace ();} #S') i1;  
} 8;Eg>_cL:  
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//读取保存的下载信息（文件指针位置） K\y W{y
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private void read_nPos() B f"L;L  
{ MHF7hk ps}  
try{ `&5_~4T7  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ]D&\|,,(
 
int nCount = input.readInt(); /{FS
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nStartPos = new long[nCount]; A? T25<}  
nEndPos = new long[nCount]; I|R;)[;X  
for(int i=0;i<nStartPos.length;i++) #Z1 <lAy  
{ *rv7#!].  
nStartPos = input.readLong(); MoMxKmI  
nEndPos = input.readLong(); WI\jm&H r  
} _8&a%?R@W  
input.close(); iNv"!'|  
} @JU Xp  
catch(IOException e){e.printStackTrace ();} prO
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catch(Exception e){e.printStackTrace ();} IUSV\X9  
} j+NsNIJq  
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private void processErrorCode(int nErrorCode) l }WvO]  
{ !]2`dp\!  
System.err.println("Error Code : " + nErrorCode); 9Z lfY1=  
} _l{_n2D-  
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//停止文件下载 iKA}??5e  
public void siteStop() @ *n oma  
{ E5 uk<e_  
bStop = true; ZfnJ&H'  
for(int i=0;i<nStartPos.length;i++) gaU1A"S}  
fileSplitterFetch.splitterStop(); Q1[EiM3  
8&c:73=?X  
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} Z:.*fs5  
} 3B?7h/f  
//负责部分文件的抓取 ]7J*(,sp  
**FileSplitterFetch.java |^C35 6M>  
*/ *Z2#U?_  
package NetFox; X{tfF!+iy  
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import java.io.*; 5m9;'SF  
import java.net.*; 3h**y %^  
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public class FileSplitterFetch extends Thread { 'Oa(]Br[  
I;+>@Cn(g<  
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String sURL; //File URL ?9ScKN  
long nStartPos; //File Snippet Start Position oL -udH  
long nEndPos; //File Snippet End Position 7O<K?;I  
int nThreadID; //Thread's ID g^[BnP)I  
boolean bDownOver = false; //Downing is over {"mb)zr  
boolean bStop = false; //Stop identical ie}?}s  
FileAccessI fileAccessI = null; //File Access interface OpLUmn  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (\H^KEy  
{ 9@wmngvM*Y  
this.sURL = sURL; T~)R,OA7m  
this.nStartPos = nStart; )uC5  
this.nEndPos = nEnd; FZx.Yuv  
nThreadID = id; Y3bZ&G)  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 '4,>#D8@O  
} 2 sK\.yS  
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public void run() GU7f27p  
{ Ti&v9re%wO  
while(nStartPos < nEndPos && !bStop) V?-SvQIk1  
{ cXbQ  
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try{ xP$\ }  
URL url = new URL(sURL); %H3 M0J2L  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7.bPPr&  
httpConnection.setRequestProperty("User-Agent","NetFox"); [WO>}rGw4  
String sProperty = "bytes="+nStartPos+"-"; ')>D*e  
httpConnection.setRequestProperty("RANGE",sProperty); U(5Yg  
Utility.log(sProperty); Ny G?^  
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InputStream input = httpConnection.getInputStream(); >r.W \  
//logResponseHead(httpConnection); Yz? 8n  
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byte[] b = new byte[1024]; o "1X8v  
int nRead; (lt{$0   
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 0,j!*  
{ 0gH;y+\=*  
nStartPos += fileAccessI.write(b,0,nRead); :(#5%6F  
//if(nThreadID == 1) tgC)vZ&a  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *{dMo,.eI  
} LN`Y`G|op  
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Utility.log("Thread " + nThreadID + " is over!"); PLRMW2  
bDownOver = true; o<Qt<*  
//nPos = fileAccessI.write (b,0,nRead); Zty9O8g  
} 23/;W|   
catch(Exception e){e.printStackTrace ();} naVbcY  
} v$#l]A_D  
} T9bUt|  
}A&
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//打印回应的头信息 h_15"rd  
public void logResponseHead(HttpURLConnection con) [wn! <#~v  
{ hkx(r5o  
for(int i=1;;i++) ._TN;tR~'  
{ uMX\Y;N  
String header=con.getHeaderFieldKey(i); 7'Gkip  
if(header!=null) Y{9xF8#  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); }70A>JBw  
Utility.log(header+" : "+con.getHeaderField(header)); tv%B=E!r  
else id[caP=`  
break; '3fN2[(  
} ~nb1c:F  
} TNlOj a:  
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public void splitterStop() QBb%$_Z  
{ CTJwZY7  
bStop = true; J=b'b%  
} R)6"P?h._4  
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} d fSj= 4  
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/* ! =*k+gpF  
**FileAccess.java wY"BPl]b  
*//文件访问(定位，写) rUZ09>nDy  
package NetFox; :Z+Jt=;  
import java.io.*; 2^y*O  
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1AQy8n*  
public class FileAccessI implements Serializable{ h!?rk|  
fWyXy%Qq  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 eIQ@){lJ-]  
RandomAccessFile oSavedFile; !,R=6b$E5  
long nPos; [DvQk?,t  
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public FileAccessI() throws IOException ~.CmiG.7  
{ & l0LW,Bx  
this("",0); B`:l;<&jX  
} b-RuUfUn0  
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]q/USVj{  
public FileAccessI(String sName,long nPos) throws IOException k:URP`w[X=  
{ (*9-
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oSavedFile = new RandomAccessFile(sName,"rw"); *W2o$_Hs  
this.nPos = nPos; c$x>6&&L  
oSavedFile.seek(nPos); `eeA,K_  
} Z9eP(ip  
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public synchronized int write(byte[] b,int nStart,int nLen) A2SD
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{ L~C:1VG5  
int n = -1; -_= m j  
try{ <u/(7H
 
oSavedFile.write(b,nStart,nLen); nO#x"  
n = nLen; e-#Vs{?|r  
} /@&#U bN\  
catch(IOException e) |,tKw4  
{ }s[`T   
e.printStackTrace (); HSVl$66  
} QOY{j  
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return n; ZEso2|   
} l#Vg=zrT  
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} qfjUJ/  
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B  
/* eJeL{`NS  
**SiteInfoBean.java MG~bDM4  
*/ rQosI:$  
package NetFox; 1iqgVby  
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public class SiteInfoBean { .y lv
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private String sSiteURL; //Site's URL '8[; m_S  
private String sFilePath; //Saved File's Path P#D|CP/Cu  
private String sFileName; //Saved File's Name J 5xMA-  
private int nSplitter; //Count of Splited Downloading File zRb
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1jO%\uR/  
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public SiteInfoBean() .R l7,1\  
{//nSplitter的缺省值为5 Pm,.[5uc  
//default value of nSplitter is 5 x2'pl (^  
this("","","",5); 4-I7"pW5  
} ".2d{B  
*f_A:`:  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) VJ?>o  
{ 4c[/%e:\-  
sSiteURL= sURL; #2Iag'4T  
sFilePath = sPath; ]k'^yc{5  
sFileName = sName; Qqx!'
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this.nSplitter = nSpiltter; :
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} /0$fYrg>J  
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public String getSSiteURL() noM=8C&U  
{ 1vxQ`)a  
return sSiteURL; Gp+\}<^Z  
} '.M4yif\g  
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public void setSSiteURL(String value) Ln t 1  
{ *")*w> R  
sSiteURL = value; 53gLz_ee  
} 
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public String getSFilePath() {+nf&5E 6  
{ V1pBKr)v  
return sFilePath; 4 Y
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} l1KgPRmEP  
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public void setSFilePath(String value) ~KYzEqy  
{ wc.=`Me  
sFilePath = value; iy_Y!wZ{  
} Pq8oK'z-  
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public String getSFileName() ^g5E&0a`g  
{ i q oXku  
return sFileName; )Jdku}Pf  
} 5bAdF'~  
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public void setSFileName(String value) 6@t&  
{ 2QM{e!9  
sFileName = value; o-7{\%+M  
} yNowhh
 
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public int getNSplitter() C\~}ySQc.e  
{ Bv!{V)$  
return nSplitter; q?dd5JzZy,  
} x\(#  
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public void setNSplitter(int nCount) W/hzo*o'g  
{ u~i
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nSplitter = nCount; "YY<T&n  
} 1*2ycfa  
} )Uy%iE*  
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/* ]& ckq  
**Utility.java lnHY?y7{  
*/ peBHZJ``RX  
package NetFox; #qYgQ<TM!  
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public class Utility { 7Q9Hk(Z9  
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public Utility() Z4Dx:m
-  
{ n]`]gLF\i  
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} gBv!E9~l  
q+9->D(6  
//线程睡眠 _ia&|#n  
public static void sleep(int nSecond) \}v@!PQl  
{ ">CRFee0  
try{ v:QUwW  
Thread.sleep(nSecond); j8p<HE51  
}   8sG?|u  
catch(Exception e) pxgf%P<7  
{ oo\^}jb  
e.printStackTrace (); i/+^C($'f  
} k
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} l`zhKj  
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//日志 /y{:N  
public static void log(String sMsg) T&dNjx  
{ rIPfO'T?  
System.err.println(sMsg); P
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} mMwV5\(  
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v77UE"4|c  
public static void log(int sMsg) iv_3R}IbX  
{ f&4+-w.:V|  
System.err.println(sMsg); eLPtdP5k  
} Hq 5#.rZ#  
} \O"H#gt  
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/* fYy w2"  
**TestMethod.java pJ}U'*Z2  
*/ l+F29_o#  
package NetFox; yZ,pH1  
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OU7OX]h  
public class TestMethod { !7I07~&1  
"[~yu* S  
9nc_$H{  
public TestMethod() 2~f*o^%l  
{ ///xx/weblogic60b2_win.exe ~/K&=xE  
try{ X,l7>>L{g  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 8A&N+sT  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 2[`n<R\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 'uL$j
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fileFetch.start(); yg'CL/P  
} W`
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catch(Exception e){e.printStackTrace ();} vw!7f|Pg ~  
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} 1q!k#Cliu  
1
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public static void main(String[] args) C('D]u$Hdk  
{ wsB-( 0-  
new TestMethod(); ,jC~U s<  
} k8}fKVU;  
} 6O{QmB0KK  
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