http断点续传简单实现（java)

/* J<27w3bs~p  
**SiteFileFetch.java [ m#|[%  
*/ v
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package NetFox; ^wTod\y  
import java.io.*; xu(N'l.7&  
import java.net.*; M9d
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public class SiteFileFetch extends Thread { (I0QwB  
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SiteInfoBean siteInfoBean = null; //文件信息Bean t/Y)%N  
long[] nStartPos; //开始位置 xa]e9u%  
long[] nEndPos; //结束位置 s:f%=4-7  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )a0%62  
long nFileLength; //文件长度 ;($"_h  
boolean bFirst = true; //是否第一次取文件 /^^wHW:  
boolean bStop = false; //停止标志 F?*ko,  
File tmpFile; //文件下载的临时信息 JR^#NefJ  
DataOutputStream output; //输出到文件的输出流 N2/t  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） `p\@b~GM  
public SiteFileFetch(SiteInfoBean bean) throws IOException LqcHsUFj  
{ Di>
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siteInfoBean = bean; /+g)J0
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Lcow2 SbH  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); A{,ZfX;SPO  
if(tmpFile.exists ()) ~3r}6,%  
{ au~}s |#  
bFirst = false; ~uRL+<.c  
read_nPos(); 9f7T.}HM  
} \$[; d:9j  
else o5`LLVif5y  
{ = k7}[!T  
nStartPos = new long[bean.getNSplitter()]; qEy]Rc%  
nEndPos = new long[bean.getNSplitter()]; ;rjd?r  
} ]^c]*O[8  
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} {- Y.C
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public void run() 9}*<8%PSt,  
{ ie9,ye"  
//获得文件长度 .Mz'h9@  
//分割文件 X|wg7>kh*`  
//实例FileSplitterFetch JVawWw0q  
//启动FileSplitterFetch线程 %9Y3jB",2  
//等待子线程返回 dRu|*s  
try{ G ;fc8a[X  
if(bFirst) ae-hQ
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{ i3v|r 0O~L  
nFileLength = getFileSize(); TF7~eyLg  
if(nFileLength == -1) 7'1 +i  
{ jt,dr3|/n  
System.err.println("File Length is not known!"); X\ bXat+  
} H(,D5y`k1  
else if(nFileLength == -2) V3t;V-Lkt  
{ KV {J>J1  
System.err.println("File is not access!"); l0GsY.~,  
} R
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else =&YhA}l\O  
{ .sE5QRVc  
for(int i=0;i<nStartPos.length;i++) Q( g&/O  
{ SdM@7%UK  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 71(C@/J  
} ?@LqrKj11  
for(int i=0;i<nEndPos.length-1;i++) GiGXV @dq  
{ .]D7Il  
nEndPos = nStartPos[i+1]; #Rx|oSc}  
} 1Bhd-  
nEndPos[nEndPos.length-1] = nFileLength; q[Ed6FM$~  
} c3]X#Qa#m$  
} 7ElU5I<S  
I {&8iUN  
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//启动子线程 >J,y1jzJ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \I[50eh|  
for(int i=0;i<nStartPos.length;i++) 
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{ "B"Yfg[  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ( {}Z '  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), x
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nStartPos,nEndPos,i); eGr;PaG  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); l:$i}
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fileSplitterFetch.start(); TOC2[mc'  
} ~&\}qz3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /CfgxPo  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &w"1VOV<  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", lwj,8  
nEndPos = " + nFileLength); L^><APlX  
// fileSplitterFetch[nPos.length-1].start(); DJ.n8hne  
M>LgEc-v67  
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//等待子线程结束 ;I@@PUnR  
//int count = 0; h#o?O k  
//是否结束while循环 \#O}K  
boolean breakWhile = false; guc[du  
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while(!bStop) kD.KZV  
{ jSc!"Trl]  
write_nPos(); bxR6@  
Utility.sleep(500); BfOQ/k))  
breakWhile = true; H)VzPe#{  
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for(int i=0;i<nStartPos.length;i++) W0_ pO  
{ 7ea<2va,  
if(!fileSplitterFetch.bDownOver) /.m&rS  
{ 6! .nj3$*  
breakWhile = false; HJ^SqSm  
break; yNU.<d 5  
} 1 |T{RY5  
} jPc"qER!  
if(breakWhile) {Z!x]}{M  
break; pS6p}S=1]  
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//count++; DITo.PU  
//if(count>4) Ae[Na:G+  
// siteStop(); {2,vxGi  
} Z\. n6  
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System.err.println("文件下载结束！"); &Ay[mZQ 7  
} NcMohpkq  
catch(Exception e){e.printStackTrace ();} AAW])c`.  
} /|MHZ$Y9w?  
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//获得文件长度 pEp`Z,p  
public long getFileSize() 2*)2c[/0F  
{ K~6,xZlDWM  
int nFileLength = -1; rU!QXg]uD  
try{ 4#"_E:;PQ  
URL url = new URL(siteInfoBean.getSSiteURL()); HY!R|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ky#5G-X  
httpConnection.setRequestProperty("User-Agent","NetFox"); K*id 1YY  
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int responseCode=httpConnection.getResponseCode(); z}z 6Vg  
if(responseCode>=400) T0TgV  
{ ($or@lfs  
processErrorCode(responseCode); Vl\8*!OL%  
return -2; //-2 represent access is error M%(^GdI#Vf  
} #ExNiFZ  
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String sHeader; <reALC  
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for(int i=1;;i++) :}*  
{ sFbN)Cx  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); <N'v-9=2jl  
//Utility.log(in.readLine()); V]Z!x.x"=y  
sHeader=httpConnection.getHeaderFieldKey(i); ``:+*4e9  
if(sHeader!=null) kWMz;{I5*w  
{ 7U647G(Sg  
if(sHeader.equals("Content-Length")) OUF
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{ 1"yr`,}?8r  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); n4sO#p)'  
break; r?2EJE2{V  
} ,[UK32KWI  
} xNOArb5e5  
else a${<~
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break; ^gSZzJ5  
} $+  
} i9koh3R\  
catch(IOException e){e.printStackTrace ();} 'B\7P*L"p  
catch(Exception e){e.printStackTrace ();} fHd|tl  
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Utility.log(nFileLength); G$mAyK:  
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return nFileLength; Rl{e<>O\^  
} B&L-Lc2  
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//保存下载信息（文件指针位置） N@#,YnPI  
private void write_nPos() Lm3~< vP1e  
{ 4&kC8 [r  
try{ Bw/8-:eb  
output = new DataOutputStream(new FileOutputStream(tmpFile)); %urd;h
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output.writeInt(nStartPos.length); VjLv{f<p  
for(int i=0;i<nStartPos.length;i++) 0PD=/fh[  
{ _)kTlX:,  
// output.writeLong(nPos); U!i1~)s  
output.writeLong(fileSplitterFetch.nStartPos); ]_(J8v  
output.writeLong(fileSplitterFetch.nEndPos); uL{CUt  
} /*2)|2w  
output.close(); IqAML|C  
} [9^lAhX  
catch(IOException e){e.printStackTrace ();} ("KtJ  
catch(Exception e){e.printStackTrace ();} Bwl@Muw  
} 0,whTnH|  
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//读取保存的下载信息（文件指针位置） 4w5);x.  
private void read_nPos() #w@V
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{ g{^~g  
try{ GIZw/L7Yb  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Ge7Uety  
int nCount = input.readInt(); Nsn~mY%  
nStartPos = new long[nCount]; cq0-Dd9^&  
nEndPos = new long[nCount]; ryNe=9p  
for(int i=0;i<nStartPos.length;i++) 5=&ME(fmV  
{ c!ieN9^+  
nStartPos = input.readLong(); J9-n3o  
nEndPos = input.readLong(); X;]Ijha<*  
} \q@Co42n\  
input.close(); YeS5%?Fk  
} s}F.D^^G  
catch(IOException e){e.printStackTrace ();} 1
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catch(Exception e){e.printStackTrace ();} }qT{" *SC  
} [vqf hpz  
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private void processErrorCode(int nErrorCode) k+BY3a  
{ +rJDDIb  
System.err.println("Error Code : " + nErrorCode); :s*t\09V7  
} K7R!E,oPg  
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//停止文件下载 2<9&OL  
public void siteStop() wk#cJ`wG;  
{ lVCnu>8  
bStop = true; :%_h'9Qq  
for(int i=0;i<nStartPos.length;i++) Vi`P &uPF  
fileSplitterFetch.splitterStop(); KM"BHaSkF  
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} DwGRv:&HH  
} vmg[/#  
//负责部分文件的抓取 nC(Lr,(  
**FileSplitterFetch.java 2@W`OW Njm  
*/ y
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package NetFox; :{ iK 5  
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import java.io.*; w75Ro6y  
import java.net.*; 10Q!-K),p  
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public class FileSplitterFetch extends Thread { eX1_=?$1P  
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String sURL; //File URL d_!}9  
long nStartPos; //File Snippet Start Position CaV@<T  
long nEndPos; //File Snippet End Position +p[O|[z  
int nThreadID; //Thread's ID +/ {lz8^,  
boolean bDownOver = false; //Downing is over <0;G4fE7[H  
boolean bStop = false; //Stop identical eLLOE)x  
FileAccessI fileAccessI = null; //File Access interface ;l^'g}dQ^  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException j\"d/{7Q  
{ Lr9E02  
this.sURL = sURL; k<x7\T  
this.nStartPos = nStart; \x:} |   
this.nEndPos = nEnd; H_,4N_hL  
nThreadID = id; B2Rpd &[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 fw VI%0C@  
} "!_vQ^y  
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public void run() 4V;-*:  
{ U{qwhz(  
while(nStartPos < nEndPos && !bStop) ^q`RaX)  
{ kZhd^H.  
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try{ wwv+s~(0  
URL url = new URL(sURL); )3R5cq  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); v_WF.sb~  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8H1&=)M=  
String sProperty = "bytes="+nStartPos+"-"; QeN7~ J  
httpConnection.setRequestProperty("RANGE",sProperty); );h  
Utility.log(sProperty); XD" 4t4~>  
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InputStream input = httpConnection.getInputStream(); ZuZCIqN  
//logResponseHead(httpConnection); D^a(|L3;  
:wEy""*N0  
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byte[] b = new byte[1024]; b
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int nRead; /EJy?TON*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) !x\\# 9  
{ wz{c;v\J^  
nStartPos += fileAccessI.write(b,0,nRead); *CbV/j"P?  
//if(nThreadID == 1) _h`4`r  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :Gzp (@<@e  
} _2)QL  
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Utility.log("Thread " + nThreadID + " is over!"); =Ot_P7'5gv  
bDownOver = true; Gx4{ 9  
//nPos = fileAccessI.write (b,0,nRead); )TyP{X>  
} ;U$Rd,T4S  
catch(Exception e){e.printStackTrace ();} 'vYt_T  
} !]5V{3  
} 17`-eDd  
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//打印回应的头信息 x8x-b>|$&<  
public void logResponseHead(HttpURLConnection con) 1|AY&u%fiP  
{ fz?woVn  
for(int i=1;;i++) :`lP+y?a1  
{ }:u-l3e  
String header=con.getHeaderFieldKey(i); ?G<?:/CU  
if(header!=null) B&BL<X r  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); f@$kK?c?  
Utility.log(header+" : "+con.getHeaderField(header)); d'H gek{T  
else |DPq~l(d  
break; m
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} 6!USSipn  
} gzy|K%K  
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public void splitterStop() mB6%. "  
{ Gd'_X D  
bStop = true; Kr<UPr  
} us8HXvvp{  
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}
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/* G1*,~1i  
**FileAccess.java 9]lyV  
*//文件访问(定位，写) A_e5Vb,u.  
package NetFox; (uy\~Zb  
import java.io.*; &Nw|(z&$  
XX "3.zW  
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public class FileAccessI implements Serializable{ 9qB4\ONXZ  
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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  p:eaZ  
RandomAccessFile oSavedFile; "q!*RO'a  
long nPos; l8 $.k5X  
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public FileAccessI() throws IOException o*"Q{Xh#Qd  
{ ZG{#CC
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this("",0); O3%#Q3c>3  
} fZLAZMrM  
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public FileAccessI(String sName,long nPos) throws IOException +(z[8BJl  
{ ,U+>Q!$`\^  
oSavedFile = new RandomAccessFile(sName,"rw"); J, +/<Y!  
this.nPos = nPos;  B@*!>R  
oSavedFile.seek(nPos); -v|lM8  
} k,; (`L  
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public synchronized int write(byte[] b,int nStart,int nLen) ^#K^WV  
{ GU9p'E  
int n = -1; .7:ecF
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try{ R9D2cu,{  
oSavedFile.write(b,nStart,nLen); :S7[<SwL  
n = nLen; 57]La^#  
} X?JtEQ~>  
catch(IOException e) &.#dZ}J  
{ h?}S|>9  
e.printStackTrace (); T&bB8tQk  
} a<>cbP  
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return n; 2+pXtP@O  
} w>}n1Nc$G  
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} &OEBAtc/  
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/* ,S@B[+VZ  
**SiteInfoBean.java V?`|Ha}  
*/ zy8+~\a+Y&  
package NetFox; S
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public class SiteInfoBean { /F''4%S?E  
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private String sSiteURL; //Site's URL hstGe>f[6  
private String sFilePath; //Saved File's Path r>PKl'IbE  
private String sFileName; //Saved File's Name FFmXT/K"/j  
private int nSplitter; //Count of Splited Downloading File 'YYT1H)  
N pQOLX/<?  
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public SiteInfoBean() d>c`hQ(V  
{//nSplitter的缺省值为5 [a}Idi` K  
//default value of nSplitter is 5 F[0~{*/|G  
this("","","",5); _F^NX%  
} +&J1D8  
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7 n^1H[q  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) cS@p`A7Tpo  
{ -Ekf T_  
sSiteURL= sURL; *"6A>:rQs  
sFilePath = sPath; </SO#g^r<  
sFileName = sName; ]@}hyM[D;  
this.nSplitter = nSpiltter; TC@F*B;  
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} A@4{-e\  
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public String getSSiteURL() -~H "zu`  
{ ymnK`/J!Q  
return sSiteURL; ycvgF6Me<  
} v:>sS_^  
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public void setSSiteURL(String value)  p1&=D%/  
{ {~(XO@;b  
sSiteURL = value; -rHqU|  
} fZJM'+J@A  
77 Z:!J|  
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public String getSFilePath() I?%#`Rvu  
{ iU=:YPE+.  
return sFilePath; u09D`QPP]  
} +>c%I&h}`  
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public void setSFilePath(String value) 3hzz*9/n  
{ L}A2$@  
sFilePath = value; nvc(<Ovw  
} Ywcgt|  
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public String getSFileName() @ Yo*h"s  
{ 9\kEyb$F=  
return sFileName; 04}c_XFFE  
} Y;dqrA>@  
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public void setSFileName(String value) 2uF'\y  
{ !.4q{YWcYk  
sFileName = value; J@IKXhb7_  
} *xKy^f  
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public int getNSplitter() /R6\_oM  
{ M~Er6Zg  
return nSplitter; }wJH@'0+  
} 0wF)bQv1  
%/!f^PIwX  
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public void setNSplitter(int nCount) ,Hp7`I>/  
{ r C
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nSplitter = nCount; }We-sZ/w7r  
} 3-[+g}kak?  
} 1&Mpx!K*T  
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/* 9PaV*S(\TR  
**Utility.java , 0?_? GO  
*/ ^$rqyWZYp  
package NetFox; <u?\%iJ"  
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public class Utility { 1p<*11  
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public Utility() U0N6\+  
{ ;:Tb_4Hr  
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} f>Tn#
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//线程睡眠 <^ratz!-  
public static void sleep(int nSecond) 7$*x&We  
{ rf!i?vAe  
try{ w
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Thread.sleep(nSecond); @Q!Tvw/  
}
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catch(Exception e) f/m0,EERk  
{ uw@-.N^  
e.printStackTrace (); fEGnI
\  
} Tv|iCYB?  
} {T0Au{88H  
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//日志 'HL.W](  
public static void log(String sMsg) $wl_  
{ )t2eg1a:  
System.err.println(sMsg); c;n\HYk  
} Lg-!,Y   
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public static void log(int sMsg) Pv*]AF;9pQ  
{ z1.vnGP  
System.err.println(sMsg); :1v.Jk  
} A3J=,aRI_v  
}
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/* ^pqJz^PO.  
**TestMethod.java fd&>p  
*/ Q0g^%  
package NetFox; S2#@j#\  
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public class TestMethod { 02YmV%  
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public TestMethod() Bt(nm>Ng  
{ ///xx/weblogic60b2_win.exe Sb}=j;F  
try{ Kv ajk~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \Y6r !D9  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,Z8)DC=  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \]3[Xw-$  
fileFetch.start();  LYyud  
} &fE2zTz  
catch(Exception e){e.printStackTrace ();} %kP=VUXj  
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} xX.{(er  
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public static void main(String[] args) l4U  
{ c/l^;6O/!\  
new TestMethod(); \4O_@d`A  
} RP k'1nD  
} B'bOK`p  
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