http断点续传简单实现（java)

/* YRu/KUT$ 7  
**SiteFileFetch.java l'1_Fb  
*/ *-3*51 jW  
package NetFox; '#
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import java.io.*; WtlLqD!_D  
import java.net.*; &x3R+(H {  
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public class SiteFileFetch extends Thread { S" PJ@E}^E  
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4  
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SiteInfoBean siteInfoBean = null; //文件信息Bean #iT3aou  
long[] nStartPos; //开始位置 geNvp0  
long[] nEndPos; //结束位置 &r!jjT  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~3$:C#"Dl  
long nFileLength; //文件长度 8aY}b($*ZI  
boolean bFirst = true; //是否第一次取文件 m[%P3  
boolean bStop = false; //停止标志 82YZN5S3]3  
File tmpFile; //文件下载的临时信息 8"ulAx74>  
DataOutputStream output; //输出到文件的输出流 ynn>d  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 0KN'\KE  
public SiteFileFetch(SiteInfoBean bean) throws IOException BO>[\!=y  
{ v807)JwS  
siteInfoBean = bean; (r-PkfXvIf  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;m"R.Q9*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); hdpA& OteR  
if(tmpFile.exists ()) \/!jGy*  
{ _o-01gu.  
bFirst = false; bLC+73BjC  
read_nPos(); SQ`KR'E  
} J@IF='{  
else rW2l+:@c  
{ -e.ygiK.`S  
nStartPos = new long[bean.getNSplitter()];  -K4uqUp  
nEndPos = new long[bean.getNSplitter()]; >L^2Z*  
} -l<[CI  
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} W3xObt3w\  

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public void run() 3JZ9 G79H  
{ H,)2Ou-Wn  
//获得文件长度 J6J; !~>_  
//分割文件 Zb2.o5#}  
//实例FileSplitterFetch "9,+m$nj  
//启动FileSplitterFetch线程 cN7|Zsc\  
//等待子线程返回 ,Z(J;~  
try{ 9j1 tcT  
if(bFirst) 6~Y`<#X5J  
{ dLw,dg  
nFileLength = getFileSize(); rk `]]  
if(nFileLength == -1) 51puR8AG>  
{ *KPNWY9!W  
System.err.println("File Length is not known!"); )z7+%nTO  
} \Bn$b2j!%  
else if(nFileLength == -2) JjG>$z  
{ = $6pL  
System.err.println("File is not access!"); +|Mi lwr  
} I_'0!@Nn7  
else jxZd =%7Q  
{ <a=k"'0  
for(int i=0;i<nStartPos.length;i++) ig?Tj4kD  
{ SA.,Q~_T7  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); G=>LW1E|  
} 7;NvR4P%  
for(int i=0;i<nEndPos.length-1;i++) (L"G,l  
{ +w+qTZyky  
nEndPos = nStartPos[i+1]; xcN >L  
} &uxwz@RC0  
nEndPos[nEndPos.length-1] = nFileLength; Mh5 =]O+  
} %|3NCyJ*7  
} z.*=3   
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//启动子线程 }"AGX  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; E"b"VB  
for(int i=0;i<nStartPos.length;i++) E#,n.U>#)  
{ H_7X%TvXb  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), pAdSOR2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3
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nStartPos,nEndPos,i); /-1 F9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); a\v@^4   
fileSplitterFetch.start(); ]39A1&af}  
} q}%;O >Z  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f"A?\w@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,7izrf8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #zw 'H9l  
nEndPos = " + nFileLength); &^
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// fileSplitterFetch[nPos.length-1].start(); Z sbE  

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+X7+:QQ}  
//等待子线程结束 R6dD17  
//int count = 0; f*ZIBTb 9  
//是否结束while循环 %/=#8v4*  
boolean breakWhile = false; qU:Mvb^5&  
x2H?B`5  
j!QP>AM|`  
while(!bStop) vq*)2.  
{ Zkn1@a  
write_nPos(); >-YWq  
Utility.sleep(500); 3}X;WE `  
breakWhile = true; |%-:qk4rG  
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NQhlb"Ix  
for(int i=0;i<nStartPos.length;i++) 0Xw3h^%  
{ $5a%hK  
if(!fileSplitterFetch.bDownOver) b7? 2Pu  
{ [lX3":)  
breakWhile = false; `)s>},8W!  
break; 7=x]p
  
} }mSfg  
} 3QzHQU  
if(breakWhile) oyY0!w,Y  
break; >L>t$1hXM  
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Ga}&%  
//count++; _rf  
//if(count>4) kQMALS@R  
// siteStop(); tL~?)2uEN  
} JOJ?.H&su  
ckPI^0A!  
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System.err.println("文件下载结束！"); xYCX}bksh  
} 5KFd/9  
catch(Exception e){e.printStackTrace ();} XK4idC  
} 4`#3p@-  
/|2#s%|-=  
-wj
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//获得文件长度 UP}5Eh  
public long getFileSize() Wg2Y`2@t  
{ l4s_9  
int nFileLength = -1; t
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try{ K@zzseQ}=  
URL url = new URL(siteInfoBean.getSSiteURL()); pC'GKk 8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Qc
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httpConnection.setRequestProperty("User-Agent","NetFox"); T5+iX`#M  
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int responseCode=httpConnection.getResponseCode(); .OC{,f+  
if(responseCode>=400) ^#VyIF3q  
{ ^?)o,djY&  
processErrorCode(responseCode); }$ZcC_  
return -2; //-2 represent access is error XABI2Ex  
} >-{)wk;1&  
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Y|iJO>_Uu=  
String sHeader; DdL0MGwX  
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~rX2oLw{&  
for(int i=1;;i++) a}+7MEUmZ/  
{ =@d IM  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Cq,ox'kGl  
//Utility.log(in.readLine()); YdK]%%  
sHeader=httpConnection.getHeaderFieldKey(i); R~],5_|  
if(sHeader!=null) 3./4] _p  
{ N3Jfp3_b@  
if(sHeader.equals("Content-Length")) zp2IpYQ,3  
{ !`G7X  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |NcfR"[c  
break; Y(4#b`k3  
} '_~=C-g  
} Ex ?)FL$4  
else 4S]`S\w  
break; 6NV- &0 _  
} P#g"c.?;  
} ^p0BeSRiy;  
catch(IOException e){e.printStackTrace ();} #Pz},!7  
catch(Exception e){e.printStackTrace ();} iraO/KhD*3  
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Utility.log(nFileLength); @i9T),@  
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return nFileLength; z Lw=*  
} VR/>V7*7@  
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//保存下载信息（文件指针位置） XTHy CK  
private void write_nPos() 3JiDi X"|  
{ 1|VnPQqA  
try{ wPDA_ns~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )hHkaI>eYv  
output.writeInt(nStartPos.length); (N U*PQY6  
for(int i=0;i<nStartPos.length;i++) F(8>"(C  
{ dE+xU(\,w  
// output.writeLong(nPos); qF{u+Ms  
output.writeLong(fileSplitterFetch.nStartPos); 8}0W_CU,  
output.writeLong(fileSplitterFetch.nEndPos); l("Dw8H  
} )j40hrR  
output.close(); 7mSVL\\^  
} Elt=/,v`!  
catch(IOException e){e.printStackTrace ();} N4%q-fi  
catch(Exception e){e.printStackTrace ();} ~h] <E  
} RpE69:~PV  
dFF[2  
 ? {Lp  
//读取保存的下载信息（文件指针位置） &Z_W*D  
private void read_nPos() V@Z8t8  
{ +'H_sMmi{  
try{ zQ$*!1FmN  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));
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int nCount = input.readInt(); xD;5z`A3  
nStartPos = new long[nCount]; dlC)&Ai
 
nEndPos = new long[nCount]; zLlu%Oc  
for(int i=0;i<nStartPos.length;i++) ;$G.?r  
{ 9}FWO&LiB  
nStartPos = input.readLong(); nB
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nEndPos = input.readLong(); )DsC:cP  
} J'O</o@e  
input.close(); Z@=1-l  
} :J-@+_J  
catch(IOException e){e.printStackTrace ();} a[:0<Ek  
catch(Exception e){e.printStackTrace ();} n^|n6(EZ  
} /lSz8h2  
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private void processErrorCode(int nErrorCode) h#?L6<*tm  
{ 5tg  
System.err.println("Error Code : " + nErrorCode); 1O1/P,u+  
} ?k~(E`ZE3  
"z\T$/  
5B!l6ST  
//停止文件下载 uYlC*z{  
public void siteStop() }u&.n pc  
{ T^8t<S@`  
bStop = true; 1Fn+nDnO6  
for(int i=0;i<nStartPos.length;i++) NaSgK  
fileSplitterFetch.splitterStop(); |b{XnD_g  
|eIN<RY5  
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} w} *;^n  
} (bi}?V*
 
//负责部分文件的抓取 S*6P=O*  
**FileSplitterFetch.java 1Tf"<Dp  
*/ o~,dkV
  
package NetFox; cA1"Nek  
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import java.io.*;  /E/J<  
import java.net.*; a&~d,vC  
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p5c^dC{  
public class FileSplitterFetch extends Thread { $ +;`[b   
&'4id[$9  
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String sURL; //File URL _e$15qW+  
long nStartPos; //File Snippet Start Position L5E.`^?  
long nEndPos; //File Snippet End Position ^SB?NRk  
int nThreadID; //Thread's ID nnX,_5s  
boolean bDownOver = false; //Downing is over Jz s.)  
boolean bStop = false; //Stop identical  Q0'xn  
FileAccessI fileAccessI = null; //File Access interface Mxn>WCPo  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ziR}  
{ |BnjT*_9  
this.sURL = sURL; s_-G`xT>{  
this.nStartPos = nStart; 1HG~}E  
this.nEndPos = nEnd; v!T%xUb0  
nThreadID = id; >tnQuFKg]  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 zRdL-u%(#  
} );V6YE  
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W[[3'JTF  
public void run() D)XF@z;  
{ V*rAZ0  
while(nStartPos < nEndPos && !bStop) 1u7Kc'.xc  
{ tgH@|Kg  
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try{ O^48c$Apv  
URL url = new URL(sURL); *|ez|*-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~;k-/Z"  
httpConnection.setRequestProperty("User-Agent","NetFox"); m'k.R j  
String sProperty = "bytes="+nStartPos+"-"; yTwv2l;U  
httpConnection.setRequestProperty("RANGE",sProperty); R>U0W{1NO  
Utility.log(sProperty); W/9dT^1y4'  
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InputStream input = httpConnection.getInputStream(); C1^=se  
//logResponseHead(httpConnection); "5u*C#T2$  
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byte[] b = new byte[1024]; qc\]~]H]r  
int nRead; cS/\&%7u  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) x2/\%!mt  
{ xal+buOiP  
nStartPos += fileAccessI.write(b,0,nRead); z=B*s!G  
//if(nThreadID == 1) $^?"/;8P5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ehu^_HZ  
} nIJ2*QJ  
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6lOT5C eJ"  
Utility.log("Thread " + nThreadID + " is over!"); 1X2MhV  
bDownOver = true; !`L%wS  
//nPos = fileAccessI.write (b,0,nRead); 9 o6ig>C  
} w~hO)1c],:  
catch(Exception e){e.printStackTrace ();} B}8xA}<  
} &{NN!X  
} 6/Y3#d  
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@9g$+_"ZT  
//打印回应的头信息 St9W{  
public void logResponseHead(HttpURLConnection con) C-lv=FJEk/  
{ Ahk6{uz  
for(int i=1;;i++) Nw[TP G5  
{ =mxG[zDtQ  
String header=con.getHeaderFieldKey(i); XQ]noaU  
if(header!=null) &^Q-:Kxs8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >%5Ld`c:SD  
Utility.log(header+" : "+con.getHeaderField(header)); awh<CmcZ  
else 9HrT>{@  
break; n@ lf+  
} ,
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} WzZ<ZCHm  
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public void splitterStop() H)z}6[`  
{ P*Va<'{:{  
bStop = true; LgXc}3  
} TeaP\a  
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} "1|n]0BF  
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/* F \6-s`(  
**FileAccess.java =i[_C>U  
*//文件访问(定位，写) Xc~yr\%]  
package NetFox; xR}^~14Bz  
import java.io.*; Y!s94#OaZ  
jWk1FQte  
5e=9~].7  
public class FileAccessI implements Serializable{ Hc^q_{}"  
7pf]h$2  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -L&r2RF/  
RandomAccessFile oSavedFile; K}7E;O5m"  
long nPos; koDIxj'%X  
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public FileAccessI() throws IOException Pj(DlC7G,  
{ c-1,((p  
this("",0); OQ>8Q
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} :bt;DJ@  
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public FileAccessI(String sName,long nPos) throws IOException #4UK
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{ & -L$B  
oSavedFile = new RandomAccessFile(sName,"rw"); k|V%*BvY>  
this.nPos = nPos; Nki08qZ[  
oSavedFile.seek(nPos); tNP>6F/  
} :Z)a&A9v  
r,I';vm<`  
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public synchronized int write(byte[] b,int nStart,int nLen) RlW0U-%u  
{ ]e`&py E  
int n = -1; d
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try{ &h^E_]P  
oSavedFile.write(b,nStart,nLen); }#%3y&7M7  
n = nLen; A$d)xq-]K  
} &%eWCe++  
catch(IOException e) Wk<heF  
{ X
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e.printStackTrace (); Lv;% z  
} b)ytm=7ha  
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return n; _v=S4A#tF  
} k*XI/k5Vc  
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v *'anw&Z  
} aia`mO]  
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u NmbR8Mx  
/* xib?XzxGo  
**SiteInfoBean.java !@>_5p>q*  
*/ Vx'82CIC  
package NetFox; :\hcl&W:  
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public class SiteInfoBean { P;~`%,+S  
?X $#J'U;  
l$[7pM[  
private String sSiteURL; //Site's URL lL8
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private String sFilePath; //Saved File's Path rK` x<  
private String sFileName; //Saved File's Name
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private int nSplitter; //Count of Splited Downloading File SXqWq  
f6/<lSoW  
BQWhTS7  
public SiteInfoBean() yV"k:_O{  
{//nSplitter的缺省值为5 r_
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//default value of nSplitter is 5 xA7>";sla[  
this("","","",5); GgT 5'e;N  
} +lYo5\1=  
uX/K/4  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) h D5NX  
{ ^Pwtu  
sSiteURL= sURL; |ty?Ah,vb  
sFilePath = sPath; 5:R$xgc  
sFileName = sName; Zc!rL0
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this.nSplitter = nSpiltter; DsJ ikg(J  
5r2A^<)  
mYUR(*[  
} ) |t;nK,  
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public String getSSiteURL() q\DN8IJ  
{ IL0e:-@!0  
return sSiteURL; hw5NHZ I'  
} z:Y Z]   
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public void setSSiteURL(String value)
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{ C4[)yJ  
sSiteURL = value; Y
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} X&LaAqlSG  
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7y?aw`Sw:  
public String getSFilePath() |lDxk
[  
{ oMNt676  
return sFilePath; !k3 eUBF  
} cy-o@U"s8  
&u`]Zn  
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public void setSFilePath(String value) #zf,%IYF  
{ I%|,KWM  
sFilePath = value; ~:krJ[=  
} qkbGM-H%U  
zH5
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public String getSFileName() ApD`i+Y@  
{ n 9>**&5L  
return sFileName; C^IPddw>  
} W5*Kq^6Pd  
fEo5j`}  
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public void setSFileName(String value) T)Y{>wT  
{ oNEjlV*  
sFileName = value; <da-iY\5  
} 9 _oAs"w  
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@fQvAok  
public int getNSplitter() 5
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{ A.9ZFFz  
return nSplitter; c4f3Dr'xw  
} i7XM7+}  
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public void setNSplitter(int nCount) ]?7q%7-e.a  
{ h/oC9
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nSplitter = nCount; rD;R9b"J  
} C+L_f_6]  
} pi|=3W  
^`S.Mw.  
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/* }`pxs  
**Utility.java oh
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*/ -Hh.8(!XoO  
package NetFox; p:NIRs  
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public class Utility { ],~H3u=s3  
h'nXV{N0  
8B`w!@hf  
public Utility() Fhrj$  
{ ,p>@:C/M  
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i
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} $KVCEe!X  
`%/w0,0  
//线程睡眠 G,}"}v:  
public static void sleep(int nSecond) Y 8n*o3jM  
{ R=J5L36F  
try{ @~QI3)=s  
Thread.sleep(nSecond); ?j;,:n  
} ~f:"Q(f+  
catch(Exception e) MW2{w<-]7  
{ `F$lO2#k  
e.printStackTrace (); BR-4L2[  
} udOdXz6K?  
} -
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P~*'/!@  
//日志 a$5
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public static void log(String sMsg) x#XxD<y  
{ G ?Hx"3:?  
System.err.println(sMsg); I}+9@d  
} x }@P  
3wMnTT"At  
LP'wL6#  
public static void log(int sMsg) 0!b9%I=j  
{ (h|E@gRa  
System.err.println(sMsg); ^GS\(egt  
} \<HY'[gr  
} q#O8Fv  
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aHdQi,=z  
/* h0?w V5H  
**TestMethod.java W2&(:C8V@  
*/ \30rF]F`l  
package NetFox; N/zP!%L  
d"tR?j  
NRT@"3,1YP  
public class TestMethod { z?@N+||,.  
Nt|Fw$3*5{  
3T/&T`T+c  
public TestMethod() @1A.$:  
{ ///xx/weblogic60b2_win.exe '5(T0Ws/w  
try{ h=4 GSU  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \hWac%#  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -zzoz x]S=  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %NDr5E^cc  
fileFetch.start(); ,h9?o  
} _C)\X(;  
catch(Exception e){e.printStackTrace ();} ZfXgVTJ`  
&x\cEI)!  
4t-l@zFWb  
} [V_+/[AA)  
hEFOT]P4  
26;Gt8  
public static void main(String[] args) {rwT
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{ F!fsW9  
new TestMethod(); BV6B:=E0  
} 6!se,SCvw  
} -
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