http断点续传简单实现（java)

/* 4Le{|B  
**SiteFileFetch.java YTfi g{a  
*/ lvR>%I0`*  
package NetFox; rF/<}ye/4M  
import java.io.*; Lr "V

 
import java.net.*; ci
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public class SiteFileFetch extends Thread { 8xoC9!xt  
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SiteInfoBean siteInfoBean = null; //文件信息Bean aMxM3"  
long[] nStartPos; //开始位置 w:~
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long[] nEndPos; //结束位置 Ou|kb61zg  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 uPb.uG  
long nFileLength; //文件长度 r;"Qu  
boolean bFirst = true; //是否第一次取文件 Zo Ra^o  
boolean bStop = false; //停止标志 hXc:y0 0  
File tmpFile; //文件下载的临时信息 Bv7os3xb  
DataOutputStream output; //输出到文件的输出流 bhW&,"$Z  

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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 6ziBGU#.-  
public SiteFileFetch(SiteInfoBean bean) throws IOException [E qZj/  
{ ?]_A~_J!  
siteInfoBean = bean; - G=doP0  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); U@}P]'`'f  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `mS0]/AV/  
if(tmpFile.exists ()) 7aHP;X~0  
{ PD^Cj?wm  
bFirst = false; ztC,[
 
read_nPos(); 1E$^ul-v  
} 8`|Z9umW*  
else /!hxW}>^  
{ NU3s^ 8\(  
nStartPos = new long[bean.getNSplitter()]; f!B\X*|  
nEndPos = new long[bean.getNSplitter()]; [QwqP=-6  
} ;a(7
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} jZ<f-Ff0  
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public void run() 80LN(0?x  
{ ca'c5*Fs  
//获得文件长度 o"qG'\x  
//分割文件 aBKJd  
//实例FileSplitterFetch [-nPHmZV[  
//启动FileSplitterFetch线程
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//等待子线程返回 kM
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try{ <t,lq  
if(bFirst) wf~n>e^e  
{ .h
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nFileLength = getFileSize(); yDi'@Z9R?  
if(nFileLength == -1) +"VXw2R_e  
{ d.y-R#F_]  
System.err.println("File Length is not known!"); LUA<N:  
} yY80E[v  
else if(nFileLength == -2) ]!WD">d:  
{ 7fW$jiw  
System.err.println("File is not access!"); ,d8*7my  
} Y>CZ  
else 6KX/Yj~B  
{ 2))pB/  
for(int i=0;i<nStartPos.length;i++) 1HeE$  
{ 6I\4Yv$N  
nStartPos = (long)(i*(nFileLength/nStartPos.length));
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} !Ic~_7"  
for(int i=0;i<nEndPos.length-1;i++) p$$0**p!`  
{ t'HrI-x  
nEndPos = nStartPos[i+1]; ,'@t.XP  
} Nkk+*(Z  
nEndPos[nEndPos.length-1] = nFileLength; jB\Knxm v  
} .:Zb~  
} (l)r.Vj  
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//启动子线程 T{*!.+E  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; PLK
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for(int i=0;i<nStartPos.length;i++) GO6uQ};  
{ s 5F?m  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^7Z.~A y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),
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nStartPos,nEndPos,i); xepp."
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  SB^xq  
fileSplitterFetch.start(); +QEiY~i  
} F>aaUj  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }J_#N.y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); w[/m:R?eX  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", E7@m& R  
nEndPos = " + nFileLength); Z:>ek>Op  
// fileSplitterFetch[nPos.length-1].start(); j$r2=~1  
8/W2;>?wKc  
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//等待子线程结束 ;<BMgO}N  
//int count = 0; 'I@l$H  
//是否结束while循环 o AM)<#U>  
boolean breakWhile = false; P"Y7N?\](  
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while(!bStop) /Hyi/D{W  
{ +\25ynM

 
write_nPos(); gO_d!x*  
Utility.sleep(500); DP!~WkU~  
breakWhile = true; 2h`Tn{&1/  
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for(int i=0;i<nStartPos.length;i++) .-cx9&  
{ D8)6yPwE  
if(!fileSplitterFetch.bDownOver) Vv*](iM  
{ Gg5+Ap D  
breakWhile = false; > |(L3UA9  
break; 'E4}++\  
} e^orqw/I  
} oN=>U"<\1  
if(breakWhile) bA/'IF+  
break; Z4D[nPm$  
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//count++; B[;aNyd<  
//if(count>4) }k_'a^;C1  
// siteStop(); !5>PZ{J  
} %G'P!xQhy  
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System.err.println("文件下载结束！"); *Jg&:(#}<J  
} (vwKC D&  
catch(Exception e){e.printStackTrace ();} '_FxxLAO  
} `5MK(K :  
:} DTK  
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//获得文件长度 Up\ k67  
public long getFileSize() +*x9$LSD  
{ m[Cp G=32B  
int nFileLength = -1; #2?3B  
try{ \ 9#X]H  
URL url = new URL(siteInfoBean.getSSiteURL()); ,7SqRY,+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :rEZR`  
httpConnection.setRequestProperty("User-Agent","NetFox"); PgYIQpV  
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int responseCode=httpConnection.getResponseCode(); :O]US)VSj  
if(responseCode>=400) Wn Ng3'6  
{ q)OCY}QA  
processErrorCode(responseCode); }[SYWJIc  
return -2; //-2 represent access is error yhd]s0(!  
} W@Rb"5Gy+  
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String sHeader; ) RNB;K~s9  
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for(int i=1;;i++) 0t6DD  
{ DJ|lel/'  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 
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//Utility.log(in.readLine()); _a zJ>  
sHeader=httpConnection.getHeaderFieldKey(i); mi@ni+2Tn  
if(sHeader!=null) !JA//{?  
{ `pfRY!  
if(sHeader.equals("Content-Length")) kQO-V4z!  
{ hY|-l%2f  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 05o<fa2HE  
break; W;|%)D)y
 
} 'q1cc5(ueV  
}
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else z+<ofZ(.  
break; VUZeC,FfO  
} K7wU tg  
} h8icF}m  
catch(IOException e){e.printStackTrace ();} [R<>3}50Y  
catch(Exception e){e.printStackTrace ();} L$v<t/W  
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Utility.log(nFileLength); `Nv P)|  
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return nFileLength; u4ZOHy_O^  
} =Js
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//保存下载信息（文件指针位置） C0CJ;   
private void write_nPos() 3)hQT-)  
{ 3 5/ s\  
try{ 9hjzOJPuga  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Zm6|aHx8v  
output.writeInt(nStartPos.length); +g_m|LF  
for(int i=0;i<nStartPos.length;i++)  7MQxW<0  
{ .pIO<ZAFT  
// output.writeLong(nPos); %$67*pY'JH  
output.writeLong(fileSplitterFetch.nStartPos); +NVXFjPC  
output.writeLong(fileSplitterFetch.nEndPos); Cm9#FA  
} 2IXtIE  
output.close(); 5RyxVC0<  
} /ACau<U]t  
catch(IOException e){e.printStackTrace ();} XHh*6Yt_ (  
catch(Exception e){e.printStackTrace ();} I!T=$Um  
} b"w@am>&  
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//读取保存的下载信息（文件指针位置） ubMN  
private void read_nPos() $4hi D;n  
{ NKl`IiGv  
try{ pRA%07?W  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); %JI*)K1WI  
int nCount = input.readInt(); V,]Fh5f  
nStartPos = new long[nCount]; ?Cv([ ^Y.u  
nEndPos = new long[nCount]; FIx|4[&>S  
for(int i=0;i<nStartPos.length;i++) 0rxGb} b*  
{ WAJKP"  
nStartPos = input.readLong(); Q;GcV&f;f  
nEndPos = input.readLong(); u-*z#e_L0  
} IUz`\B
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input.close(); S2>$S^[U  
} HQMug  
catch(IOException e){e.printStackTrace ();} JA4}Bwn  
catch(Exception e){e.printStackTrace ();} k}!'@  
} xXSfYW  
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private void processErrorCode(int nErrorCode) L.8`5<ITw  
{ uw(Ml=  
System.err.println("Error Code : " + nErrorCode); Gh352  
} 3gtKD9RL:  
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//停止文件下载 ??lsv(v-  
public void siteStop() 1'|g
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{ O
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bStop = true; 1C0' Gf)3  
for(int i=0;i<nStartPos.length;i++) V!N
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fileSplitterFetch.splitterStop(); wLNkXC  
?} lqu7S  
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} Vq'n$k}  
} h.kjJF  
//负责部分文件的抓取 tJA"BP3f  
**FileSplitterFetch.java p!DOc8a.\e  
*/ <r m)c.  
package NetFox; y{2\T  
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import java.io.*; zL9:e7o  
import java.net.*; .yD5>iBh  
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public class FileSplitterFetch extends Thread { J0B*V0'z
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String sURL; //File URL 4BeHj~~  
long nStartPos; //File Snippet Start Position k{U[ U1j  
long nEndPos; //File Snippet End Position )Br#R:#  
int nThreadID; //Thread's ID Lcf?VV}  
boolean bDownOver = false; //Downing is over U2CC#,b!(  
boolean bStop = false; //Stop identical 8fktk?|  
FileAccessI fileAccessI = null; //File Access interface ZD4aT1|Q7  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException VCwC$ts  
{ Yv0y8Vz@  
this.sURL = sURL; ?Ezy0>j  
this.nStartPos = nStart; wN^^_  
this.nEndPos = nEnd; &.qLE  
nThreadID = id; P)LOAe1'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Ihv@2{*(b  
} QL*RzFAD3  
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public void run() 0.2stBw  
{ /:"^,i\t  
while(nStartPos < nEndPos && !bStop) fIJX5)D  
{ ^E.mG>
 
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try{ GMB3`&qh  
URL url = new URL(sURL); ewWw  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); gtT&97tT<  
httpConnection.setRequestProperty("User-Agent","NetFox"); `g4N]<@z  
String sProperty = "bytes="+nStartPos+"-"; W|"bV 6d3  
httpConnection.setRequestProperty("RANGE",sProperty); uGHM ]"!)  
Utility.log(sProperty); I:6
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InputStream input = httpConnection.getInputStream(); 7|jy:F,w%  
//logResponseHead(httpConnection); VLJ]OW8cO  
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byte[] b = new byte[1024]; p<?lF  
int nRead; a*iKpr-:  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) OR37  
{ J:O&2g"g  
nStartPos += fileAccessI.write(b,0,nRead); s_^N=3Si   
//if(nThreadID == 1) %@|)&][hO  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &N]e pV>  
} %~k
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Utility.log("Thread " + nThreadID + " is over!"); 6']G HDK  
bDownOver = true; k'+y  
//nPos = fileAccessI.write (b,0,nRead); Ro4!y:2|  
} e/#6qCE  
catch(Exception e){e.printStackTrace ();} 1$`|$V1  
} L\5:od[EP  
} ,Q.[Lc=w  
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*'tGi_2?(  
//打印回应的头信息 S9ic4rcd  
public void logResponseHead(HttpURLConnection con) rBi6AM/  
{ K\zb+  
for(int i=1;;i++) }E[v
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{  dvz6  
String header=con.getHeaderFieldKey(i); 3\{\ al   
if(header!=null) hpYv*WH:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); m)?0;9bt  
Utility.log(header+" : "+con.getHeaderField(header)); p=#/H,2  
else E1dhj3+3  
break; U<>@)0~7g!  
} =sefT@<  
} !ZvVj\{  
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public void splitterStop() 2I& dTxIa  
{ DY{v@ <3  
bStop = true; G)c+GoK  
} <a&xhG}  
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} .726^2sx  
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/* R y(<6u0  
**FileAccess.java B&<5VjZ\  
*//文件访问(定位，写) m1X*I  
package NetFox; >[wB|V5  
import java.io.*; ,?IXfJ`c  
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public class FileAccessI implements Serializable{ Cbl
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pGF;,h>  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 }_}    
RandomAccessFile oSavedFile; bj0<A  
long nPos; Ciz,1IV  
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public FileAccessI() throws IOException ?<Hgq8J  
{ jC$~m#F  
this("",0); O '`|(L  
} %++S;#)~  
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public FileAccessI(String sName,long nPos) throws IOException 8 nqF i  
{ qJO6m-  
oSavedFile = new RandomAccessFile(sName,"rw"); -dN`Ok<g  
this.nPos = nPos; ~l.C
-  
oSavedFile.seek(nPos); 59v=\; UI  
} Vpzjh,r-j  
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xj&~>&U){;  
public synchronized int write(byte[] b,int nStart,int nLen) cxvO,8NiB  
{ ="f-I9y  
int n = -1; [;4ak)!  
try{ I9rQX9#B  
oSavedFile.write(b,nStart,nLen); O8N1gf;t  
n = nLen; ~E_irzOFP  
} c* ~0R?  
catch(IOException e) *~cNUyd  
{ Ux{QYjFE  
e.printStackTrace (); heB![N0:  
} fA0wQz]u  
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return n; =CS$c?  
} *f{4_ts  
,
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} e6qIC*C!  
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/* !{ _:k%B  
**SiteInfoBean.java AW9%E/{  
*/ 1=E}X5  
package NetFox; ,?Vxcr  
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public class SiteInfoBean { n<HF]  
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private String sSiteURL; //Site's URL QwF.c28[  
private String sFilePath; //Saved File's Path p]Qe5@NT  
private String sFileName; //Saved File's Name a9_2b}t  
private int nSplitter; //Count of Splited Downloading File e8egxm  
p)"EenUK  
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public SiteInfoBean() 6W7,EIf  
{//nSplitter的缺省值为5 :0Y.${h  
//default value of nSplitter is 5 d(9SkXr  
this("","","",5); HM"(cB(n`  
} .>PwbZ  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) C:bA:O  
{ <S;YNHLC  
sSiteURL= sURL; XRyeEwA;pp  
sFilePath = sPath; kI5LG6  
sFileName = sName; 3W.D^^)eCV  
this.nSplitter = nSpiltter; Z3ODZfu>  
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} 0tMzVxS  
V/R@=[  
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public String getSSiteURL() (5[#?_~  
{ 36.mf_AM  
return sSiteURL; -(}N-yu  
} W&Xi&[Ux  
5"q{b1  
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public void setSSiteURL(String value) YxA nh  
{ R_Bf JD.  
sSiteURL = value; =FFs8&PKys  
} o$*DFvk  
^BI&-bR@  
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public String getSFilePath() c]z^(:_>  
{ Ml+f3#HP  
return sFilePath; 8-b~p  
} =U:]x'g(  
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public void setSFilePath(String value) S=~+e{  
{ T).}~i;!  
sFilePath = value; {c&9}u$e  
} gK dNgU  
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public String getSFileName() E!I4I'  
{ .Dr7YquW  
return sFileName; v yP_qG  
} td#m>S  
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public void setSFileName(String value) 7bJM $   
{ >S?7-2X  
sFileName = value; '64/2x  
} jd 8g0^  
&N%-.&t'  
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public int getNSplitter() *\Hut'7 d  
{ ~H]d9C  
return nSplitter; /`O'eH  
} 5=4-IO6W[]  
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3|Ar~_]  
public void setNSplitter(int nCount) I&x69  
{ Ww{-(Ktx  
nSplitter = nCount; -r0oO~KT  
} 1;>RK  
} xlW>3'uHfa  
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/* HI)U6.'  
**Utility.java i l%9j  
*/ mj y+_  
package NetFox; o%Qn%gaX  
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public class Utility { o`}8ZtD  
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public Utility() [|HQfTp$  
{ %';DBozZ  
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ZPY84)A_}  
} e9B$"_ &2  
!|Y&h0e  
//线程睡眠
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public static void sleep(int nSecond) bHHR^*B  
{ x1:1Jj:  
try{ +OUM 4y  
Thread.sleep(nSecond); ZJ_P=  
} Zt4 r_7  
catch(Exception e) HL!"U(_  
{ D/WzYc2h]  
e.printStackTrace (); @jD19=  
} j7HOh
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} "QY~V{u5  
Q $>SYvW  
//日志 ,
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public static void log(String sMsg) wtGb3D"am  
{ /B  
System.err.println(sMsg); jbTyM"Y  
} j!`2Z@  
:#W>lq@H  
vYG
$>*  
public static void log(int sMsg) Aj=c,]2  
{ R~BW=Dz,e  
System.err.println(sMsg); W{;LI WsZ  
} d _koF-7  
} fP1fm  
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q
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/* sk`RaDq@;  
**TestMethod.java rB5+~ K@  
*/ lnntb3q  
package NetFox; ~


9+\  
k+cHx799  
aeF^&F0  
public class TestMethod { 7kidPAhY  
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public TestMethod() cNqw(\rr  
{ ///xx/weblogic60b2_win.exe :y[tZ&*<_?  
try{ Q|cA8Fn  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Ad`jV_z  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 1Aa=&B2  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Yy0m &3[  
fileFetch.start(); <8/lHQ^\)  
} w+tO@  
catch(Exception e){e.printStackTrace ();} rx;zd?  
aw/5#(1R  
n 6|\  
} R2[!h1nZ  
Rd*/J~TK  
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public static void main(String[] args) :J+GodW  
{ u8@>ThPD  
new TestMethod(); #/`V.jXt>  
} M3 $MgsN:  
} LHP?!rO0  
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