http断点续传简单实现（java)

/* ?4t~z 1.f  
**SiteFileFetch.java `(]mU
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*/ ceLr;}?Ws  
package NetFox; GuF-HP}xM  
import java.io.*; %;#9lkOXWH  
import java.net.*;
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public class SiteFileFetch extends Thread { _zLEHEZ-  
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SiteInfoBean siteInfoBean = null; //文件信息Bean +A%zFF3  
long[] nStartPos; //开始位置 #2+hu^Q-  
long[] nEndPos; //结束位置 3*R(&O6}  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 n65fT+;  
long nFileLength; //文件长度 d;a"rq@a)  
boolean bFirst = true; //是否第一次取文件 7o-}86x#  
boolean bStop = false; //停止标志 %5;kNeD\Fq  
File tmpFile; //文件下载的临时信息 Up>,~bs]  
DataOutputStream output; //输出到文件的输出流 #+^l3hMK  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） hDbZ62DDN  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]@qD4:  
{ |[!0ry*N%  
siteInfoBean = bean; xRF_'|e  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ?h8/\~Dw  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); yCv"(fNQ  
if(tmpFile.exists ()) FWo`oJeN  
{ s%
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bFirst = false; V{{UsEVO  
read_nPos(); WX+@<y}%  
} t5QGXj  
else x!onan  
{ .>'J ^^  
nStartPos = new long[bean.getNSplitter()]; r
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nEndPos = new long[bean.getNSplitter()]; z=LO$,JW`  
} /Wy9".  
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} V.[b${  
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public void run() }Ub "Vb  
{ [{J1b  
//获得文件长度 &jDRRT3  
//分割文件 T{T> S%17~  
//实例FileSplitterFetch 1'5!")r  
//启动FileSplitterFetch线程 hflDVG
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//等待子线程返回 +7K]5p;!~  
try{ Uzk_ae  
if(bFirst) cr{dl\Na  
{ hy:K) _   
nFileLength = getFileSize(); 2aQ}| `  
if(nFileLength == -1) U7G|4(  
{ Vb2")+*:  
System.err.println("File Length is not known!"); *c@]c~hY,  
} cH7D@p}  
else if(nFileLength == -2)  ^9kdd[  
{ t*Wxvoxk  
System.err.println("File is not access!"); NO#^_N`#\  
} ,0$b8lb;x/  
else ||?wRMV  
{ OL[_2m*;9p  
for(int i=0;i<nStartPos.length;i++) tWdP5vfp  
{ QpifO  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 2K'}Vm+  
} uMP&.Y(  
for(int i=0;i<nEndPos.length-1;i++) OZh+x`' #  
{ zdDJcdbGd1  
nEndPos = nStartPos[i+1]; !?)iP  
} W/;qMP1"-  
nEndPos[nEndPos.length-1] = nFileLength; "(?[$R  
} {c$%3iQq  
} B Zw#ACU  
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//启动子线程 u"a$/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;D<rGkry  
for(int i=0;i<nStartPos.length;i++) ,<-a 6  
{ &nZ.$UK<  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), j8p'B-yS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ]%%cc  
nStartPos,nEndPos,i); k<S!|  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0 .p $q  
fileSplitterFetch.start(); AwL;-|X  
} 3!B
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @KYmkxW  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); -OP5v8c f  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2!Ex55  
nEndPos = " + nFileLength); Onoi6^G  
// fileSplitterFetch[nPos.length-1].start(); _mL9G5~r  
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jW",'1h
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//等待子线程结束 L=}U
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//int count = 0; +=@Z5eu  
//是否结束while循环 p:ST$1 K  
boolean breakWhile = false; M !OI :v  
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while(!bStop) @kwD$%*0  
{ 7"JU)@ U]  
write_nPos(); U>x2'B v  
Utility.sleep(500); .]H]H*wC  
breakWhile = true; hOMFDfhU  
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for(int i=0;i<nStartPos.length;i++) 90aPIs-  
{ 1,`x1dcO!A  
if(!fileSplitterFetch.bDownOver) %dT%r=%Y  
{ Pjb9FCA'  
breakWhile = false; Azz]TO  
break; L}a3!33)C  
} IL:"]`f*  
} ,em6wIq,  
if(breakWhile) pr0V)C6  
break; t1Khf  
#CQ>d8&  
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//count++; khv!\^&DD  
//if(count>4) X-{:.9  
// siteStop(); }\DQxHG  
} j*:pW;)^  
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System.err.println("文件下载结束！");
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} e<^4F%jSK  
catch(Exception e){e.printStackTrace ();} kyo ,yD  
} Z%OSW  
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//获得文件长度 nG%j4r ;  
public long getFileSize() VD#^Xy4% r  
{ !d0@^JbM"  
int nFileLength = -1; Xp?Z;$r$  
try{ a@jP^VVk  
URL url = new URL(siteInfoBean.getSSiteURL()); 49zp@a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }\*Sf[EMD  
httpConnection.setRequestProperty("User-Agent","NetFox"); dw4)4_  
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int responseCode=httpConnection.getResponseCode(); 6~/H#8Kdn  
if(responseCode>=400) KnFbRhu[  
{ #EM'=Q%TO  
processErrorCode(responseCode); #129 i2  
return -2; //-2 represent access is error #dfW1@m  
} y14@9<~9  
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String sHeader; TnaIRJ\B  
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for(int i=1;;i++) B&$89]gs|  
{ ~3YNHm6V  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); LGMFv  
//Utility.log(in.readLine()); y d$37G|n  
sHeader=httpConnection.getHeaderFieldKey(i); 2Ls<OO  
if(sHeader!=null) t]o gn(  
{ l&A`  
if(sHeader.equals("Content-Length")) E>1USKxn  
{ UK<"|2^sT  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ]\ezES  
break; f\^QV  
} E{ ,O}  
} 7@"
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else XHg%X  
break; Q}T9NzOH%  
} rN~`4mZ  
} By_Ui6:D  
catch(IOException e){e.printStackTrace ();} QaO`:wJj  
catch(Exception e){e.printStackTrace ();} DRIv<=Bt  
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Utility.log(nFileLength); ]O\W<'+V  
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return nFileLength; 7| T:TbY>  
} ^Bb_NcU  
@6!JW(,]\  
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//保存下载信息（文件指针位置） =KZ4:d5  
private void write_nPos() Vel;t<1  
{ u@EM,o  
try{ ZkJM?Fzq  
output = new DataOutputStream(new FileOutputStream(tmpFile)); D.6dPzu`  
output.writeInt(nStartPos.length); xVyUUzXs  
for(int i=0;i<nStartPos.length;i++) p o`$^TB^+  
{ lBdF9F<  
// output.writeLong(nPos); KV*:,>  
output.writeLong(fileSplitterFetch.nStartPos); B# fzMaC  
output.writeLong(fileSplitterFetch.nEndPos); 1X*T219o  
} Jq#Cn+zW  
output.close(); l}2WW1b(  
} ;^*!<F%t9R  
catch(IOException e){e.printStackTrace ();} `Vi:r9|P  
catch(Exception e){e.printStackTrace ();} NHF?73:  
} @7=D]yu  
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//读取保存的下载信息（文件指针位置） 9F](%/  
private void read_nPos() `[&2K@u  
{ o4;Nb|kk9+  
try{ dE]"^O#Mc  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0mh8.  
int nCount = input.readInt(); iL, XBoE  
nStartPos = new long[nCount]; Fzs'@*  
nEndPos = new long[nCount]; Fc~w`~tv  
for(int i=0;i<nStartPos.length;i++) 5uer [1A  
{ }A7qIys$4  
nStartPos = input.readLong(); 2>k)=hl:  
nEndPos = input.readLong(); R6XMBYK^  
} m4wTg 8LJ  
input.close(); @RIEO%S  
} c1J)yv1y  
catch(IOException e){e.printStackTrace ();} h$k3MhYDes  
catch(Exception e){e.printStackTrace ();} E3skC%}  
} |mmG s  
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private void processErrorCode(int nErrorCode) lKUm_; m  
{ Bedjw =B  
System.err.println("Error Code : " + nErrorCode); ]P$DAi  
} <\g&%c,  
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//停止文件下载 Ne7{{1  
public void siteStop() ;x^,t@ xge  
{ _%vqBr*  
bStop = true; +[/r^C  
for(int i=0;i<nStartPos.length;i++) y UAn~!s  
fileSplitterFetch.splitterStop(); }>~>5jc/Pg  
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} 1cBhcYv"  
} xPup?oP >  
//负责部分文件的抓取 !<zzP LC  
**FileSplitterFetch.java '5/}MMT  
*/
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package NetFox; Zw][c7%  
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import java.io.*; }@%ahRGx%9  
import java.net.*; BQ&q<6Tk  
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public class FileSplitterFetch extends Thread { N%A`rY}u  
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String sURL; //File URL "%Ana=cc  
long nStartPos; //File Snippet Start Position m%c0#=D  
long nEndPos; //File Snippet End Position F}(Q
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int nThreadID; //Thread's ID aiZo{j<6  
boolean bDownOver = false; //Downing is over 0"psKf'  
boolean bStop = false; //Stop identical @1?]$?u&  
FileAccessI fileAccessI = null; //File Access interface [Cqqjv;_  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Vnj/>e3  
{ *X l<aNNx  
this.sURL = sURL; BDkBYhz;7  
this.nStartPos = nStart; #7-@k-<|  
this.nEndPos = nEnd; :n9xH  
nThreadID = id; C'czXZtn  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 nQ17E{^pR  
} :LiDJF  
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public void run() Vt=(2d5:p  
{ 8J3@VD.  
while(nStartPos < nEndPos && !bStop) V9j1j}  r  
{ Tj21YK.mk  
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try{ %y\eBfW,/  
URL url = new URL(sURL); 72ViPWW  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Kq 4<l  
httpConnection.setRequestProperty("User-Agent","NetFox"); n_aNs]C9R  
String sProperty = "bytes="+nStartPos+"-"; W0MnGzZ  
httpConnection.setRequestProperty("RANGE",sProperty); mH*@d"  
Utility.log(sProperty); 2Uv3_i<  
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InputStream input = httpConnection.getInputStream(); CLY6 YB' R  
//logResponseHead(httpConnection); afF+*\xXN  
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byte[] b = new byte[1024]; 8| e$  
int nRead; 9;]wF8h  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Sm$j:xw<  
{ .pIR/2U\F  
nStartPos += fileAccessI.write(b,0,nRead); e(w/m(!Wny  
//if(nThreadID == 1) mKq<'t]^k  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dxn0HXU  
} *$Lz2 ]  
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Utility.log("Thread " + nThreadID + " is over!"); PM-PP8h  
bDownOver = true; Q6.*"`  
//nPos = fileAccessI.write (b,0,nRead); qTTn51  
} } }f_  
catch(Exception e){e.printStackTrace ();} m c\
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} M*O(+EM  
} IQw %|
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//打印回应的头信息 GL5^_`n  
public void logResponseHead(HttpURLConnection con) i9;27tT~<  
{ }*.:Hv"  
for(int i=1;;i++) j!S1Y0CV  
{ 'l' X^LMD  
String header=con.getHeaderFieldKey(i); 0n*rs=\VG  
if(header!=null) VZ2.w4b  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); chO'Q+pw  
Utility.log(header+" : "+con.getHeaderField(header)); hg&w=l  
else Q)G!Y (g\  
break; ~Un64M?  
} DhWWN>I  
} D(qHf9  
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public void splitterStop() CO:*x,6au  
{ c>S"`r  
bStop = true; Mr=}B6`  
} TZh\#dp4l  
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} |7QVMFZ  
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/* qSEB}1  
**FileAccess.java 66~e~F}z  
*//文件访问(定位，写) %Lp2jyv.  
package NetFox; MUbhEau?  
import java.io.*; 5;FP.{+  
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public class FileAccessI implements Serializable{ oUQGLl!V  
;'=VrE6  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 X2\E9hJg  
RandomAccessFile oSavedFile; X)Dqeb6  
long nPos; DC|xilP1O  
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public FileAccessI() throws IOException BgJkrv7~  
{ m x3}m?W
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this("",0); [as-3&5S  
} oMh~5 W  
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public FileAccessI(String sName,long nPos) throws IOException FNz84qVIx'  
{ 3TU'*w &  
oSavedFile = new RandomAccessFile(sName,"rw"); 7o;x
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this.nPos = nPos; >"cr-LB  
oSavedFile.seek(nPos); s.^c..e75C  
} *nYB o\@g  
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public synchronized int write(byte[] b,int nStart,int nLen) gI)w^7Gi  
{ <K.Bq]
 
int n = -1; I:F'S#  
try{ EvwbhvA(  
oSavedFile.write(b,nStart,nLen); 0=OD?48<  
n = nLen; E x_L!9>!  
} 4id3P{aU  
catch(IOException e) i^je.,Bi  
{ 'rS'B.D  
e.printStackTrace (); WYSck&9  
} T?H\&2CLT  
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return n; t-!Rgg$9  
} Z,0O/RFJ.q  
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} qPsyqn?Y|  
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/* oz%h)#;  
**SiteInfoBean.java /"(b.&  
*/ ]KsGkAG  
package NetFox; 8]My k>  
54=}GnZN  
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public class SiteInfoBean { 3QCMK^#Z:  
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private String sSiteURL; //Site's URL xttYn]T  
private String sFilePath; //Saved File's Path b![t6-f^z  
private String sFileName; //Saved File's Name U8YO0}_z  
private int nSplitter; //Count of Splited Downloading File NtHbwU,  
kfVZ=`p}  
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public SiteInfoBean() !\aV0,  
{//nSplitter的缺省值为5 rwoF}}  
//default value of nSplitter is 5 q1UBKhpnH  
this("","","",5); --Oprl  
} }W1^t  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) GUKDhg,W  
{ wjuGq.qIu  
sSiteURL= sURL; e d_m +NM  
sFilePath = sPath; ll_}&
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sFileName = sName; fb/qoZ  
this.nSplitter = nSpiltter; aJI>FTdK  
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} 3KtAK9PT  
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public String getSSiteURL() {&uT3*V1  
{ 6mwvI4)  
return sSiteURL; Pow|:Lau!  
} ,`<]>;s  
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mLJDxh'B  
public void setSSiteURL(String value) $>;a'f~  
{ $;y1Qiel  
sSiteURL = value; 7 xUE,)?  
} 3Mw}R6g@#  
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public String getSFilePath() fO#?k<p  
{ ,pn)>  
return sFilePath; 9MT3T?IS  
} rm
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public void setSFilePath(String value) A&NqQ V,  
{ 6>s=CiZB  
sFilePath = value; jSB'>m]  
} 1ADv?+j)A/  
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public String getSFileName() A9t8`|1"%H  
{ M</Wd{.g"  
return sFileName; p/N62G  
} +SyUWoM  
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public void setSFileName(String value) /V#7=,,  
{ #J\s%60pt  
sFileName = value; dKb ^x^  
} Gh'X.?3   
|<1M&\oaQ'  
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public int getNSplitter() RYH)AS4w'  
{ \p3v#0R{  
return nSplitter; h<)yJh  
} 6i| ~7md,  
!j{CuA/  
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public void setNSplitter(int nCount) O)`Gzx*ShU  
{ s047"Q  
nSplitter = nCount; LaclC]yLU  
} %uua_&#)  
} lr0M<5d=p  
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f  
/* rEmwKZF'  
**Utility.java Si]X rub  
*/ gn^!"MN+g  
package NetFox; $
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public class Utility { _\UIc;3Gl  
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h  
{<!hlB  
public Utility() %P;[fJ `G  
{ QAi1,+y]7w  
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} mVt3W
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ncj!KyU  
//线程睡眠 ]=|P<F  
public static void sleep(int nSecond) [8TS"ph>  
{ <cj}:H *  
try{ B2Z0  
Thread.sleep(nSecond); }qL~KA{&  
} >;7a1+`3  
catch(Exception e) ]q&tQJ/Fa  
{ ??j&i6sp  
e.printStackTrace (); Td&d,;  
} pjdo|  
} oBC]UL;8xJ  
s*.3ZS5  
//日志 z>p]/Sa  
public static void log(String sMsg) ++0rF\&  
{ zQ_z7FJCB  
System.err.println(sMsg); 9*DEv0}a^  
} 5x2L(l-2  
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p_r4^p\  
public static void log(int sMsg)
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{ l|7O)  
System.err.println(sMsg); ;P8(Zf3wJb  
} +<{m45  
} %i595Ij-]  
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/* 8O9Gs  
**TestMethod.java ;Yv14{T!  
*/
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package NetFox; R+uw/LG  
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public class TestMethod { nd.hHQ  
7 OWsHlU  
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public TestMethod() ,_bp)-OG  
{ ///xx/weblogic60b2_win.exe fK"iF@=Z`  
try{ {[tZ.1.w  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #Z0-8<\  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); (kY@7)d'e  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 9DPb|+O-  
fileFetch.start(); {Xv3:"E"O  
} ]=Pu\eE  
catch(Exception e){e.printStackTrace ();} ]'g:B p  
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} >jKjh!`)!e  
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public static void main(String[] args) mrqaM2,(I  
{ 59Nd}wPO;  
new TestMethod(); cJ/4Gl  
} Yt*vqm[WV  
} JnHNkCaU  
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