http断点续传简单实现（java)

/* k]l
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**SiteFileFetch.java ^;$a_eR  
*/ 4&!`Yi_1L  
package NetFox; }I}RqD:`  
import java.io.*; x,@cU}D  
import java.net.*; Jj*XnL*  
,;y5Mu8  
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public class SiteFileFetch extends Thread { vi["G7  
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SiteInfoBean siteInfoBean = null; //文件信息Bean "63
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long[] nStartPos; //开始位置 ?lnX."eAdB  
long[] nEndPos; //结束位置 us"SM\X#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 uNxR#S  
long nFileLength; //文件长度 xV}E3Yj2#  
boolean bFirst = true; //是否第一次取文件 !3v!BJ#+,&  
boolean bStop = false; //停止标志 }?$d~]t)  
File tmpFile; //文件下载的临时信息 y+_GL=J  
DataOutputStream output; //输出到文件的输出流 tcSn`+Bu_`  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类）
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public SiteFileFetch(SiteInfoBean bean) throws IOException QB'-`GwL  
{ pjvChl5  
siteInfoBean = bean; q!$ZBw-7>A  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); I{;s.2  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); D\ HmY_  
if(tmpFile.exists ()) 4gG&u33RrE  
{ =&U JFu  
bFirst = false; `S2YBKz,1  
read_nPos(); ,6~c0]/  
} ~=aGv%vX  
else ,u-i9`B  
{ 6P;IKOv^  
nStartPos = new long[bean.getNSplitter()]; J1cD)nM<A  
nEndPos = new long[bean.getNSplitter()]; 3:&!Q*i;  
} 8RVNRV@g%  
;VSHXU'H  
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} &1ASWllD  
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public void run() 4C/  
{ ;-~Wfh+  
//获得文件长度 QxwZ$?w%  
//分割文件 Se9I1~mX  
//实例FileSplitterFetch 8wp)aGTcU  
//启动FileSplitterFetch线程 9IIQon  
//等待子线程返回 KRd.Ubs -  
try{ sOa`Tk  
if(bFirst) {# ;e{v  
{ HTao)`.  
nFileLength = getFileSize(); 5u'"m<4  
if(nFileLength == -1) ,DqI> vx|  
{ ls
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System.err.println("File Length is not known!"); BB-E"
<  
} ~P 1(%FZ  
else if(nFileLength == -2) M\ vj&T{k  
{ s4Lqam!  
System.err.println("File is not access!"); ,'v]U@WK  
} iK#5HW{  
else (5]<t&M  
{ fKY6stJE  
for(int i=0;i<nStartPos.length;i++) h`-aO u  
{ v AP)(I  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); r"x|]nvg^  
} }_u1'  
for(int i=0;i<nEndPos.length-1;i++) *F1!=:&s  
{ q+.DZ @  
nEndPos = nStartPos[i+1]; 4`)`%R$  
} 2>l4$G0  
nEndPos[nEndPos.length-1] = nFileLength; r@5_LD@f  
} G&)A7WaC  
} \\AufAkJ  
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hn{]Q@(I  
//启动子线程 >0~|iRySi  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; r&@#,g  
for(int i=0;i<nStartPos.length;i++) 75v 5/5zRn  
{ Bwj^9J/ob  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), } 1^/[?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 6T! *YrS  
nStartPos,nEndPos,i); 2Vas`/~u~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `*mctjSN  
fileSplitterFetch.start(); `of 5h*k  
} j2\bCGY  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <k-&Lh:o3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); =o^oMn  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8ME_O~,N  
nEndPos = " + nFileLength); 2~Z P[wr  
// fileSplitterFetch[nPos.length-1].start(); FPE[}  
YHAhF@&  
5
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//等待子线程结束 S9S8T+  
//int count = 0; .0kltnB  
//是否结束while循环 tsVQXvo  
boolean breakWhile = false; 
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}-?_c#G3  
while(!bStop) t}>6"^}U  
{ *%5.{J!  
write_nPos(); x9k(mn%,  
Utility.sleep(500);
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breakWhile = true; FivgOa  
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for(int i=0;i<nStartPos.length;i++) secD `]  
{ _TfG-Ae  
if(!fileSplitterFetch.bDownOver) U\a.'K50F  
{ jq:FDyOAW  
breakWhile = false; F$QN>wPpM  
break; B{$4s8XU  
} j&,,~AZm  
} A;7p  
if(breakWhile) 0O<g)%Vz>  
break; xpCzx=n3.m  
+EjH9;gx  
=cI -<0QSn  
//count++; 0h/gqlTK1  
//if(count>4) T;K@3]FbX  
// siteStop(); @[h)M3DFd  
} GEj/Z};;[b  
o7 ^t- L  
;U=IbK*  
System.err.println("文件下载结束！"); ]Q1
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} H&\[iZ|-N  
catch(Exception e){e.printStackTrace ();} gw' uY$  
} mRU-M|  
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//获得文件长度 rDFDrviW_  
public long getFileSize() BwMi@r =  
{ s\2
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int nFileLength = -1; VM=A#}  
try{ uJ<nW%}  
URL url = new URL(siteInfoBean.getSSiteURL()); lVF}G[B  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "#1KO1@G  
httpConnection.setRequestProperty("User-Agent","NetFox"); V'?bZcRr~  
*`$Y!uzG:\  
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int responseCode=httpConnection.getResponseCode(); H8.Aq\2S  
if(responseCode>=400) J&Ig%&/  
{ g$bbm}6S  
processErrorCode(responseCode); x}v]JEIf[Q  
return -2; //-2 represent access is error
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} >xrO W`p]  
D=Ia$O0.  
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String sHeader; JrlDTNJj'  
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for(int i=1;;i++) K8`Jl=}z%&  
{ JLgk?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !SRElb A;i  
//Utility.log(in.readLine()); )y>o;^5
'  
sHeader=httpConnection.getHeaderFieldKey(i); xPMTmx?2  
if(sHeader!=null) v0uDL7  
{ -OV:y
],-  
if(sHeader.equals("Content-Length")) 6[3oOO:uo  
{ \yt-_W=
[  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Sl,X*[HGd  
break; Mj&`Y gW5a  
} D>Ij  
} d&[Ct0!++u  
else ~*"]XE?M  
break; ;#-yyU  
}  dxHKXw  
} %c+`8 wj  
catch(IOException e){e.printStackTrace ();} 12l-NWXf  
catch(Exception e){e.printStackTrace ();} ab"6]%_  
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Utility.log(nFileLength); MI8f(
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return nFileLength; J)(KGdk  
} 3"v k$  
;Q*=AW  
]`@= ;w  
//保存下载信息（文件指针位置） c%|K x  
private void write_nPos() Jv_KZDOdk  
{ 'Mp8!9=&  
try{ st~ 1[in  
output = new DataOutputStream(new FileOutputStream(tmpFile)); F3d: W:^_  
output.writeInt(nStartPos.length); Y2lBQp8'|  
for(int i=0;i<nStartPos.length;i++) +,oEcCi  
{ wxC&KrRF  
// output.writeLong(nPos); (4:&tm/;  
output.writeLong(fileSplitterFetch.nStartPos); ^G:}%4  
output.writeLong(fileSplitterFetch.nEndPos); j}P x
q  
} )v\zaz  
output.close(); M"XILNV-~  
} poLzgd  
catch(IOException e){e.printStackTrace ();} G@$Y6To[  
catch(Exception e){e.printStackTrace ();} bogw/)1  
} ,Sz`$'^c  
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//读取保存的下载信息（文件指针位置） t<8vgdD  
private void read_nPos() Oz8"s4Y7  
{ Z8vMVo  
try{ Ug :3)q[O  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _FpZc?=  
int nCount = input.readInt(); 8+}yf.`  
nStartPos = new long[nCount]; RbOEXH*]  
nEndPos = new long[nCount]; cV;<!f+  
for(int i=0;i<nStartPos.length;i++) VTS7K2lBvX  
{ y$i^C:N  
nStartPos = input.readLong(); 0)<\jo1 F  
nEndPos = input.readLong(); `O5 Hzb(}  
} p2m@0ou  
input.close(); Myj5qh  
} VkFvV><"  
catch(IOException e){e.printStackTrace ();} MTnW5W-r9  
catch(Exception e){e.printStackTrace ();} #6g9@tE  
} >z{*>i,m1  
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4KbOyTQ  
private void processErrorCode(int nErrorCode) 6_UCRo5h%  
{ @*Y"[\"$  
System.err.println("Error Code : " + nErrorCode); 7(8i~}  
} :?uUh  
[N@t/^gRC  
tW^oa  
//停止文件下载 gu1:%raXd  
public void siteStop() WFr;z*  
{ F!k3/z  
bStop = true; qS8p)pw  
for(int i=0;i<nStartPos.length;i++) t(~V:+W9  
fileSplitterFetch.splitterStop(); ot%^FvQ[c  
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u& 4i=K'x8  
} c+BD37S  
} L3N?^^]  
//负责部分文件的抓取 !xE/  
**FileSplitterFetch.java _cRCG1
CJ  
*/ J\@ r~x5G  
package NetFox; ,0hk)Vvr3  
>Bw<THx  
x]6-r`O7r  
import java.io.*; |\}&mBR  
import java.net.*; w}20l F  
h+\+9^l6|  
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public class FileSplitterFetch extends Thread { @PQ% xcOC7  
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v[7iWBqJ  
String sURL; //File URL s'7PHP)LOJ  
long nStartPos; //File Snippet Start Position ?IN'Dc9&%-  
long nEndPos; //File Snippet End Position 24g\xNnt  
int nThreadID; //Thread's ID $a@T:zfe  
boolean bDownOver = false; //Downing is over v3*y43  
boolean bStop = false; //Stop identical nE
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FileAccessI fileAccessI = null; //File Access interface i]cD{hv  
9mmkFaBQ  
^ gMkQYo(#  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException WX-J4ieL  
{ f]_{4Olk  
this.sURL = sURL; =%)Y, )"  
this.nStartPos = nStart; ~|:U"w\[=  
this.nEndPos = nEnd; 7:M`k#oDP  
nThreadID = id; x>]14bLz  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 icrcP ~$A  
} 3 P=I)q  
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public void run() jW8,}Xs  
{ ?lPn{oB9"  
while(nStartPos < nEndPos && !bStop) `MLOf  
{ k#g` n3L  
f,}(=
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try{ bo-AM]  
URL url = new URL(sURL); &E?TR A# E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Vr^UEu.w?  
httpConnection.setRequestProperty("User-Agent","NetFox"); Vsj1!}X:  
String sProperty = "bytes="+nStartPos+"-"; W?:e4:Q  
httpConnection.setRequestProperty("RANGE",sProperty); /&i6vWMhP  
Utility.log(sProperty); =#Z+WD-E  
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InputStream input = httpConnection.getInputStream(); QomihQnc  
//logResponseHead(httpConnection); : MEB] }  
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byte[] b = new byte[1024]; mx!EuF$I  
int nRead; 8}?wi[T  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2JhE`EVH  
{ /prR;'ks  
nStartPos += fileAccessI.write(b,0,nRead); w7%.EA{N  
//if(nThreadID == 1) 1RgERj  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {y%|Io`P  
} '>^!a!<G  
!jTxMf  
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Utility.log("Thread " + nThreadID + " is over!");  ?8/T#ox  
bDownOver = true; hh[@q
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//nPos = fileAccessI.write (b,0,nRead); QPyHos`  
} b[2 #t  
catch(Exception e){e.printStackTrace ();} W9G1w
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} E)iX`Xq|0{  
} 4c]=kbGW  
( }RJW:  
3+/^  
//打印回应的头信息 ;)ku SH  
public void logResponseHead(HttpURLConnection con) ;L@p|]fu  
{ O>LqpZ  
for(int i=1;;i++) KIGMWS^^  
{ 0F%/R^mw  
String header=con.getHeaderFieldKey(i); [9;[g~;E%m  
if(header!=null) 4J{W8jX  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `uof\D<']  
Utility.log(header+" : "+con.getHeaderField(header)); ^4~?]5Y\  
else ET[>kn^#  
break;
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} s}<i[hY>  
} |vPU]R>
6  
 WjsmLb:5  
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public void splitterStop()
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{ $YiG0GK<"  
bStop = true; )agrx76]3w  
} v:gdG|n"  
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} 2@Zw#2|
]  
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/* hiEosI C  
**FileAccess.java r@c!M|m@  
*//文件访问(定位，写) *pYawT  
package NetFox; 0O?\0k;o  
import java.io.*; #('GGzL6c  
tI<6TE'!p#  
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public class FileAccessI implements Serializable{ %RIlu[J  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 gbu*6&j9  
RandomAccessFile oSavedFile; q\/xx`L  
long nPos;
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public FileAccessI() throws IOException G6bvV*TRi  
{ .\+c{  
this("",0); p{x6BVw?>  
} Gce[RB:  
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public FileAccessI(String sName,long nPos) throws IOException e8&7W3 m  
{ bQ-n<Lx  
oSavedFile = new RandomAccessFile(sName,"rw"); `-g$ 0lm7  
this.nPos = nPos; w19OOD  
oSavedFile.seek(nPos); w>4( hGO  
} ^ f[^.k$3d  
y/>Nx7C0=2  
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public synchronized int write(byte[] b,int nStart,int nLen) mGoNT  
{ I9h{fB  
int n = -1; qOAhBZ~  
try{ #V.u[:mO  
oSavedFile.write(b,nStart,nLen); XEUS)X)  
n = nLen; qga\icQr  
} rAk;8)O$  
catch(IOException e) Rl'xEtaN  
{ xLP8*lvy  
e.printStackTrace (); b_)SMAsO7  
} #n+sbx5~
7  
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tm.&k6%  
return n; p.5 *`, )  
} _6->D[dB  
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} _TyQC1 d  
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e 8^%}\F  
/* s>=$E~qq  
**SiteInfoBean.java f[q_eY  
*/ gX(8V*os^  
package NetFox; x[R?hS,0t  
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public class SiteInfoBean { Pr,C)uch  
}Qh%Z)  
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private String sSiteURL; //Site's URL mhF@S@  
private String sFilePath; //Saved File's Path _)~|Z~  
private String sFileName; //Saved File's Name u1|v3/Q-  
private int nSplitter; //Count of Splited Downloading File qc3?Aplj  
W+.?J 60  
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public SiteInfoBean() !q8A!P4|'  
{//nSplitter的缺省值为5 0Qg%48u
 
//default value of nSplitter is 5 {"0n^
!  
this("","","",5); !v*#E{r"g=  
} [-\DC*6  
jRp @-S#V  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) DvTbt?i[  
{  aqwW`
\  
sSiteURL= sURL; Lve$H(GHT  
sFilePath = sPath; BbI),iP  
sFileName = sName; }dSFv   
this.nSplitter = nSpiltter; Y5TBWcGU%  
(CE2]Nv9")  
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} s%
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9  
V{{UsEVO  
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public String getSSiteURL() t5QGXj  
{ x!onan  
return sSiteURL; .>'J ^^  
} %Ip=3($Ku[  
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)EG-
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public void setSSiteURL(String value) TSsx^h8/  
{ obw:@
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sSiteURL = value; U27ja|W^  
} L~_zR>  
~'):1}KN]  
'v@1_HHW\  
public String getSFilePath() ;e~K<vMm;y  
{ o#IWH;ck.  
return sFilePath; vw` '9~  
} 3iiOxg?j  
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BW  
) |hHbD^V  
public void setSFilePath(String value) Uzk_ae  
{ cr{dl\Na  
sFilePath = value; hy:K) _   
} bre6SP@  
:Czvwp{z  
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public String getSFileName() 6.4,Qae9E  
{ )sapUnqrlR  
return sFileName; s_,&"->  
} <zu)=W'R]  
,-BZsZ0~  
wJF$<f7P  
public void setSFileName(String value) A3zNUad;  
{ wD[qE  
sFileName = value; D7$xY\0r  
} Sq2yQSd  
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public int getNSplitter() OZh+x`' #  
{ Xg97[I8/  
return nSplitter; < YuI}d~'  
} \y/+H  
JDC,]  
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public void setNSplitter(int nCount) W&^2Fb  
{ F^');8~L  
nSplitter = nCount; @yjui  
} ;Y16I#?;Kh  
} t,;b*ZR  
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/* s[@@INU  
**Utility.java *-9b!>5eD  
*/ n1c Q#u  
package NetFox; M,UYDZ',  
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public class Utility { YJwz*@l  
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public Utility() <kor;exeJ  
{ +<I1@C  
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} @)8C
 
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//线程睡眠 E0S[TEDa]  
public static void sleep(int nSecond) kLqFh<  
{ Wkv**X}  
try{ &On0)G3Rc  
Thread.sleep(nSecond); O^gq\X4}  
} f:g<Bz=u)*  
catch(Exception e) u]cnbm  
{ Cj):g,[a  
e.printStackTrace (); I@q>ES!1H  
} am05>c9  
} }Mo9r4}  
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//日志 "Hjw  
public static void log(String sMsg) et]*5Y6  
{ M+^K,  
System.err.println(sMsg); 0+:.9*g=k  
} .]H]H*wC  
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public static void log(int sMsg) T[q-$8U  
{ cCV"(Oo[H|  
System.err.println(sMsg); v981nJ>w,  
} .Na>BR\F  
} D&9j$#9Rh  
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/* Yhw* `"X  
**TestMethod.java c[y=K)<Z  
*/ TcfBfscU  
package NetFox; Jp-ae0 Ewa  
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public class TestMethod { 'HcDl@E  
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LMG\jc?,  
public TestMethod() M<~F>(wxA  
{ ///xx/weblogic60b2_win.exe NxX1_d  
try{ N[+dX_h  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =;/h{ t  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ycAQPz}=I  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 'qd")  
fileFetch.start(); ]VYl Eqe  
} -% fDfjP  
catch(Exception e){e.printStackTrace ();} cT0g, ^&  
( L6`_)  
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} 3CHte*NL=  
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public static void main(String[] args) !aEp88u  
{ jw[`_  
new TestMethod(); tQ}gBE63  
} &^7)yS+C  
} -)I_+N  
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