http断点续传简单实现（java)

/* vSi_t K4  
**SiteFileFetch.java K\XH4kic  
*/ TuW%zF/  
package NetFox; 3~nnCR[R  
import java.io.*; Fu&EhGm6  
import java.net.*; L\y;LSTU  
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public class SiteFileFetch extends Thread { \(t@1]&jw  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ?wnzTbJN  
long[] nStartPos; //开始位置 hXqD<?  
long[] nEndPos; //结束位置 V& C/Z}\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 u%~igt@x  
long nFileLength; //文件长度 +cD!1IT:  
boolean bFirst = true; //是否第一次取文件 6N)!aT9eo  
boolean bStop = false; //停止标志 3O7!`Nm@  
File tmpFile; //文件下载的临时信息 $Of0n` e  
DataOutputStream output; //输出到文件的输出流 #j *d^j&  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） BD`2l!d  
public SiteFileFetch(SiteInfoBean bean) throws IOException WVY\&|)$  
{ ]E]2o  
siteInfoBean = bean; 1"pw  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `,Ph/oM  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); *N{emwIq  
if(tmpFile.exists ()) H\XP\4#u  
{ XJLQ{  
bFirst = false; gY@N~'f;"  
read_nPos(); J>u
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} {uGP&c
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else .BFYY13H  
{ Ok n(pJ0  
nStartPos = new long[bean.getNSplitter()]; 2Ry1b+\  
nEndPos = new long[bean.getNSplitter()]; &3yD_P_3  
} F <hJp,q9  
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} 4.IU!.Uo  
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public void run() #!)n {
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{ >
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//获得文件长度 ss5m/i7  
//分割文件 da (km+  
//实例FileSplitterFetch ?JL:CBvCp  
//启动FileSplitterFetch线程 C-iK$/U  
//等待子线程返回 yRo-EP  
try{ :O(^w}sle  
if(bFirst) ^5=B`aich  
{ xhRngHU\z<  
nFileLength = getFileSize(); d6W SL;$  
if(nFileLength == -1) c+
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{ b$Vz2Fzx  
System.err.println("File Length is not known!"); /%Nr?V  
} EY \H=@A  
else if(nFileLength == -2) ;\p KDPr  
{ H"qOSf{  
System.err.println("File is not access!"); @-+Q# Zz`  
} rL}YLR  
else 92^w8Z.  
{ -YsLd 9^4  
for(int i=0;i<nStartPos.length;i++) Nj?/J47?,  
{ qu|B4?Y/CR  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); .|/~op4;  
} "_`F\DGAZu  
for(int i=0;i<nEndPos.length-1;i++) S{Er?0wm.R  
{ y~75r\"R
 
nEndPos = nStartPos[i+1]; ^$t7+g  
} 6oBfB8]:d  
nEndPos[nEndPos.length-1] = nFileLength; ?:w1je7  
}
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} 8jyG"
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//启动子线程 U*3uq7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 5< ja3  
for(int i=0;i<nStartPos.length;i++) zL\OB?)5J  
{ *6} N =Z  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), hcyM6:}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), /c,(8{(O  
nStartPos,nEndPos,i); X$yN_7|+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hXA6D)
  
fileSplitterFetch.start(); ]8T!qS(UJd  
} sVl-N&/  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), VZ\B<i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); d'Zqaaf k%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", {uHU]6d3qy  
nEndPos = " + nFileLength); 0=K9`=5d0  
// fileSplitterFetch[nPos.length-1].start(); 7PkJ-JBA  
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mdw7}%5V  
//等待子线程结束 EI^06q4x  
//int count = 0; Yb
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//是否结束while循环 i@4~.iZ8  
boolean breakWhile = false; Q_t`.
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while(!bStop) [/X4"D-uOK  
{ !&"<oPjr+  
write_nPos(); Qm/u h  
Utility.sleep(500); l\sU  
breakWhile = true; m'f,_ \'  
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for(int i=0;i<nStartPos.length;i++) >Bgw}PI  
{ )LyojwY_g  
if(!fileSplitterFetch.bDownOver) ~t~-A,1  
{ Iyyh!MVF  
breakWhile = false; |gU(s  
break; 4vwTs*eB`  
} 3#TV5+x*"`  
} w.0qp)}  
if(breakWhile) 'UYR5Y>  
break; #cCL.p"]  
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//count++; #/Eb*2C`b  
//if(count>4) X3V'Cy/sy  
// siteStop(); R>(@ZM&  
} m`FNIY  
sUU{fNC6|  
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System.err.println("文件下载结束！"); ivW(*c  
} )kkhJI*v  
catch(Exception e){e.printStackTrace ();} (4Zts0O\  
} $]A/ o(  

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//获得文件长度 'FS?a  
public long getFileSize() T"0,r$
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{ ~PHB_cyth  
int nFileLength = -1; sn?]n~z  
try{ cJL'$`gWf  
URL url = new URL(siteInfoBean.getSSiteURL()); @!8ZPiW<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /
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httpConnection.setRequestProperty("User-Agent","NetFox"); 4M^G`WA}t9  
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int responseCode=httpConnection.getResponseCode(); F<(i.o(  
if(responseCode>=400) ;j)FnY=:-  
{ +fnK/%b  
processErrorCode(responseCode); C(K; zo*S(  
return -2; //-2 represent access is error 8 P>#l.#  
} jvQ*t_L  
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String sHeader; u3o#{~E/#  

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for(int i=1;;i++) !0dNQ[$82  
{ [u._q:A  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); wX*K]VMn  
//Utility.log(in.readLine()); B.L]Rk\4  
sHeader=httpConnection.getHeaderFieldKey(i); H/"lAXfb  
if(sHeader!=null) Ck/F9(  
{ <Engi!  
if(sHeader.equals("Content-Length")) ~jb"5CX  
{ MX ;J5(Ae  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =k oSUVO0  
break; mSo_} je(  
} Q[d}J+l4{  
} 8zBWIi  
else ScSZGs 5&  
break; LvEnXS  
} ykFJ%sw3X  
} -> J_ ~  
catch(IOException e){e.printStackTrace ();} MW+b;0U`#  
catch(Exception e){e.printStackTrace ();} oaK%Ww6~  
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Utility.log(nFileLength); %G?;!Lz  
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return nFileLength; _fwb!T}$  
} Kn?lHH*w7  
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//保存下载信息（文件指针位置） 5
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private void write_nPos() mB0l "# F  
{ "rAY.E]  
try{ -!8(bjlJ&  
output = new DataOutputStream(new FileOutputStream(tmpFile)); oQL59XOT4  
output.writeInt(nStartPos.length); /NFz4h=>  
for(int i=0;i<nStartPos.length;i++) P(a.iu5  
{ [JaS??ig  
// output.writeLong(nPos); sk|=% }y  
output.writeLong(fileSplitterFetch.nStartPos); @;?T~^nGj  
output.writeLong(fileSplitterFetch.nEndPos); $ F S_E
 
} Zx$ol;Yd  
output.close(); )}L??|#  
} p)~lL  
catch(IOException e){e.printStackTrace ();} P%MfCpyj  
catch(Exception e){e.printStackTrace ();} I_q~*/<h  
} z7-k`(l4  
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//读取保存的下载信息（文件指针位置） 9*:gr#(5  
private void read_nPos() RJeSi`19T)  
{ "+uNmUUnm  
try{ =KT7nl  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >Ng)k]G  
int nCount = input.readInt(); b5:op@V  
nStartPos = new long[nCount]; #*>E*#?t  
nEndPos = new long[nCount]; vEG'HOP  
for(int i=0;i<nStartPos.length;i++) W~Z<1[  
{ F6hmku>\1  
nStartPos = input.readLong(); 4m-I5!=O  
nEndPos = input.readLong(); j(#%tIv  
} -xD*tf*  
input.close(); $Q+s/4\  
} H7[6yh  
catch(IOException e){e.printStackTrace ();} mNYl@+:psj  
catch(Exception e){e.printStackTrace ();} lHB
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} !rhk $L  
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private void processErrorCode(int nErrorCode) x&A vUJ  
{ 0qFH s  
System.err.println("Error Code : " + nErrorCode); '!1$9o^$  
} 3I 0eW%,  
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W9zE{)Sc~  
//停止文件下载 ;PyZ?Z;  
public void siteStop() q|)Q9+6$+  
{ s0hBbL0DH  
bStop = true;
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for(int i=0;i<nStartPos.length;i++) rgcWRt  
fileSplitterFetch.splitterStop(); ]=F8p2w?  
O3NWXe<  
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} tK%c@gGU9  
} La[K!u\B  
//负责部分文件的抓取 GQ_Ia\  
**FileSplitterFetch.java )fU(AXSP  
*/ hF&}lPVtv  
package NetFox; <JI& {1  
q\9d6u=Gm  
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import java.io.*; (S^ck%]]a!  
import java.net.*; J0220 _  
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public class FileSplitterFetch extends Thread { *9gD*AnM,  
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String sURL; //File URL CV.+P-  
long nStartPos; //File Snippet Start Position rlznwfr7+  
long nEndPos; //File Snippet End Position `EMi0hm&H  
int nThreadID; //Thread's ID +3^NaY`Y  
boolean bDownOver = false; //Downing is over ^i_Iqph=  
boolean bStop = false; //Stop identical Jfg7\&|  
FileAccessI fileAccessI = null; //File Access interface </E>tMW  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (v#pj8aE  
{ /r
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this.sURL = sURL; z \?UGxu}  
this.nStartPos = nStart; W8aU"_  
this.nEndPos = nEnd; .gT4_  
nThreadID = id; ^b53}f8H  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 kR6A3?[  
} p#H]\P'  
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public void run() A0#Y, 1  
{ d
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while(nStartPos < nEndPos && !bStop) \{PNwF?  
{ aR:<<IF\  
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try{ SFO&=P:U  
URL url = new URL(sURL); x N`T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jp m#hH{R  
httpConnection.setRequestProperty("User-Agent","NetFox"); KU2$5[~j  
String sProperty = "bytes="+nStartPos+"-"; #%cR%Z  
httpConnection.setRequestProperty("RANGE",sProperty); f9'] jJ+  
Utility.log(sProperty); YsAF{  
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InputStream input = httpConnection.getInputStream(); $Sb@zLi)  
//logResponseHead(httpConnection); 37KU~9-A  
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byte[] b = new byte[1024]; '4
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int nRead; WF)s*$'uz;  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) l;5`0N?QO  
{ "/y|VTV"  
nStartPos += fileAccessI.write(b,0,nRead); yqBa_XPV8  
//if(nThreadID == 1) 1NGyaI  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A`C-sD>  
} yiO31uQt  
B"[{]GP BY  
bs:QG1*.  
Utility.log("Thread " + nThreadID + " is over!"); +:y&{K  
bDownOver = true; `]hCUaV   
//nPos = fileAccessI.write (b,0,nRead); fKYKW?g;)Z  
} "7?t)FO
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catch(Exception e){e.printStackTrace ();} }s6G!v^2""  
} s*+ZYPk  
} pVz pN8!  
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2*YP"R
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//打印回应的头信息 N&N 82OG  
public void logResponseHead(HttpURLConnection con) ?w8pLE~E  
{ kc|>Q7~{  
for(int i=1;;i++) ^Yr|K  
{ uOb2npPj  
String header=con.getHeaderFieldKey(i); hy=u}^F.C  
if(header!=null) 4)E|&)-fu8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); x{2o[dK4}  
Utility.log(header+" : "+con.getHeaderField(header)); $~TfL{$  
else FSVS4mtiX\  
break; 2| $k`I,  
} QglYU  
} F*X%N_n  
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public void splitterStop() Z3Gm  
{ UMv"7~  
bStop = true; |9x%gUm  
} BQuRHi IV  
at=D&oy4"+  
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MR  
} xV?*!m$V%R  
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/* xdCs5
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**FileAccess.java /AoVl'R  
*//文件访问(定位，写) \!m!ibr  
package NetFox; BZ2nDW*%  
import java.io.*; (}sDm~;s  
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public class FileAccessI implements Serializable{ i+U@\:=  
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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|b+I"M  
RandomAccessFile oSavedFile; <r0.ppgY  
long nPos; @pTD{OW?  
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public FileAccessI() throws IOException ?VU
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{ uAc@ Z-  
this("",0); #aj|vox}  
}  4c  
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public FileAccessI(String sName,long nPos) throws IOException U.HoFf+HN  
{ |*Of^IkG0  
oSavedFile = new RandomAccessFile(sName,"rw"); <'yf|N
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this.nPos = nPos; $+A%ODv  
oSavedFile.seek(nPos); UwZu:[T6H  
} (s5<  
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public synchronized int write(byte[] b,int nStart,int nLen) iTj"lA  
{ c*Eok?O  
int n = -1; hN Z4v/  
try{ hTlnw[I  
oSavedFile.write(b,nStart,nLen); 5{8x*PSl  
n = nLen; (y-x01H  
} 'bZMh9|  
catch(IOException e) TS\9<L9S  
{ &oon'q5;  
e.printStackTrace (); XRClBTKF  
} !w @1!Xpn1  
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return n; gJ<@;O8zu0  
} -}=@ *See#  
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} V}vl2o
  
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/* z*Myokhf  
**SiteInfoBean.java ?)Tz'9l  
*/ `E./p  
package NetFox; TSc~$Q]  
4]Un=?)I  
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public class SiteInfoBean { DBu)xr}7A  
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private String sSiteURL; //Site's URL {B'Gm]4  
private String sFilePath; //Saved File's Path kGB#2J  
private String sFileName; //Saved File's Name mp&Le YYn  
private int nSplitter; //Count of Splited Downloading File 4@/q_*3o  
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public SiteInfoBean() 4FfwpO3,Ku  
{//nSplitter的缺省值为5 k7z(Gbzu   
//default value of nSplitter is 5 O4 +SD  
this("","","",5); v`z=OHc  
} x?k  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) RT.wTJS;  
{ MFc=B`/X  
sSiteURL= sURL; 9 NGeh*`  
sFilePath = sPath; eHF(,JI  
sFileName = sName; 1+16i=BF)  
this.nSplitter = nSpiltter; X]+(c_i:hC  
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} ;qMnO_E  
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public String getSSiteURL() r|JiGj^om  
{ Z?.p%*>`T=  
return sSiteURL; ch)Ps2i  
} i-i}`oN  
i#M a-0#  
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public void setSSiteURL(String value) ])$."g  
{ `aO@N(  
sSiteURL = value; uDy>xJ|  
} S2At$47v  
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public String getSFilePath() Zgy2Pot  
{ *Lb(urf  
return sFilePath; 5ykk11!p$  
} gT5Ji~xI  
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public void setSFilePath(String value) RV#uy]  
{ #T$'.M  
sFilePath = value; )bIK0h  
} #g-*n@ 1  
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public String getSFileName() njwR~aL`|  
{ _ \v@9Q\  
return sFileName; sS1J.R  
} FB=  
+Qi52OG  
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public void setSFileName(String value) GmmT'3Q  
{ yZ?_q$4kEI  
sFileName = value; ax{-Qi7z-+  
} ,Zcx3C:#  
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public int getNSplitter() wzQdKlV  
{ xV n]m9i  
return nSplitter; =:n[{/O=  
} a`@<ZsR  
21/a3Mlx#  
;FgEE%  
public void setNSplitter(int nCount) ;@ll  
{ u>Axq3F  
nSplitter = nCount; dl7p1Cr  
} /nMqEHCyg  
} 7AtXG^lK  
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e/HX,sf_g  
/* k+Ma_H`  
**Utility.java C1Pt3  
*/ qLW-3W;WUH  
package NetFox; xU\:Vid+A  
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public class Utility { >gi{x|/  
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public Utility() G`9F.T_Z^)  
{ BE2\?q-  
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} ]kplb0`  
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//线程睡眠 n%ArA])_&  
public static void sleep(int nSecond) r+#V{oE_  
{ qf&a<[p~  
try{ _8b>r1$  
Thread.sleep(nSecond); _]r)6RT  
} yYg&'3  
catch(Exception e) HG3>RcB  
{ CD<u@l,1  
e.printStackTrace (); O"-PNF,J  
} |xgCV@  
} k;:u| s8NS  
kFa?q}47  
//日志 (b2^d  
public static void log(String sMsg) ]zMBZs  
{ -qCJwz30  
System.err.println(sMsg); -JO46 #m  
} V_d%g<n4  
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6exlb:  
public static void log(int sMsg) a
5~C:EU0  
{ qF6%XKbh=  
System.err.println(sMsg); [MXXY  
} y $DB  
} Cg\)BHv~  
m}'@S+k^  
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/* fu "z%h]   
**TestMethod.java +p}Xmn  
*/ gLxyRbVI  
package NetFox; z4fK{S  
dvWlx]'  
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public class TestMethod { Pk]9.e1_  
Ek
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sF3 l##Wv  
public TestMethod() qlT:9*&g  
{ ///xx/weblogic60b2_win.exe `IRT w"  
try{ 25
7;@;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); h=y(2xA  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;3}b&Z[N]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); n$0)gKN7  
fileFetch.start(); 4_:e+ ql  
} 4wD^?S!p  
catch(Exception e){e.printStackTrace ();} K:50?r_-6  
|w]i$`3
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AX Jj"hN  
} <4HuV.K  
^g){)rz|  
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public static void main(String[] args)
;RZa<2  
{ (y4Eq*n%!  
new TestMethod(); e/D\7Pf  
} C4TD@  
} s"F,=]HQ!G  
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