http断点续传简单实现（java)

/* D+xPd<  
**SiteFileFetch.java rm%MQmF  
*/ "R0(!3  
package NetFox; 1StaQUB  
import java.io.*; b[^|.>b  
import java.net.*; glomwny  
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public class SiteFileFetch extends Thread { &?*H`5#?G  
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SiteInfoBean siteInfoBean = null; //文件信息Bean J\E?rT  
long[] nStartPos; //开始位置 ^wD@)Dz  
long[] nEndPos; //结束位置 k;f%OQsF_  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 M.K%;j`  
long nFileLength; //文件长度 ;Dp<|n  
boolean bFirst = true; //是否第一次取文件 ]p*Fq^  
boolean bStop = false; //停止标志 8Z>
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File tmpFile; //文件下载的临时信息 "b[w%KYyl  
DataOutputStream output; //输出到文件的输出流 F.iJz4ya_  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） %I#[k4,N  
public SiteFileFetch(SiteInfoBean bean) throws IOException ;3&HZq6Z (  
{ Gj&`+!\  
siteInfoBean = bean; S\0?~l"}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); :+Tvq,/"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); C zxF  
if(tmpFile.exists ()) "H|hN  
{ #@:GLmD%  
bFirst = false; j4+kL4M@H  
read_nPos(); xeW}`i5_w  
} <P_B|Y4N/  
else f,VJfY?#  
{ c^7QiTt_  
nStartPos = new long[bean.getNSplitter()]; ]5+<Rqdbg  
nEndPos = new long[bean.getNSplitter()]; R]" j
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} pwmH(94$0  
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} .9!?vz]1  
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public void run() z+]YB5zK%  
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//获得文件长度 #T08H,W/  
//分割文件 QBLha']'%  
//实例FileSplitterFetch jfjT::f>l  
//启动FileSplitterFetch线程 c=<5DC&p  
//等待子线程返回 |g!3f  
try{ :|N(:W>=$Y  
if(bFirst) W$`p ,$.n  
{ HG&rE3@  
nFileLength = getFileSize(); ]L_h3Xz\X  
if(nFileLength == -1) L+Q.y~  
{ c4iGtW  
System.err.println("File Length is not known!"); c52S2f7  
} :tT6V(-W  
else if(nFileLength == -2) gUrXaD#  
{ a[7Lqu  
System.err.println("File is not access!"); lO=~&_  
} 6MmkEU z  
else 5^Ps(8VbS  
{ &5Huv?^a'  
for(int i=0;i<nStartPos.length;i++) t{Z:N']H  
{ F1NYpCR  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); qHE(p+]E  
} frUO+  
for(int i=0;i<nEndPos.length-1;i++) nE=,=K~  
{ A;
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nEndPos = nStartPos[i+1]; Mcqym8,q|3  
} :NXM.@jJ="  
nEndPos[nEndPos.length-1] = nFileLength; ,_I#+XiXY  
} 1Ts$kdO  
} \kG;T
=H  
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BL H~`N3U  
//启动子线程 wD5fm5r=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |WsB0R  
for(int i=0;i<nStartPos.length;i++) tQIa6c4|  
{ h.)o4(bO  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), W5R /  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4(TR'_X(  
nStartPos,nEndPos,i); /7uAf{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); a G\  
fileSplitterFetch.start(); 2)(ynrCe  
} Y *n[*N  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +K7oyZg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 52q<|MW%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", D0LoT?$N  
nEndPos = " + nFileLength); tlcNGPa  
// fileSplitterFetch[nPos.length-1].start(); 5'S~PQka*  
{!NXu  
*/y (~O6  
//等待子线程结束 .a7!*I#g  
//int count = 0; j S<."a/n  
//是否结束while循环 W
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boolean breakWhile = false;
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while(!bStop) ;CLOZ{  
{ @aUQy;  
write_nPos(); ?k+>~k{}a  
Utility.sleep(500); Fm4)|5  
breakWhile = true; UpS7>c7s  
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for(int i=0;i<nStartPos.length;i++) 8 EUc 6  
{ pvYBhTz0  
if(!fileSplitterFetch.bDownOver) k.!m-5E  
{ `,$PRN"]  
breakWhile = false; }$Z0v`  
break; y-lBaTE9  
} dQJ)0!B  
} H1-eMDe  
if(breakWhile) ")D5ulb\  
break; 1i/&t[  
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~;yP{F8?  
//count++; @3Gr2/a  
//if(count>4) s_%KWkS  
// siteStop(); E@_]L<Z  
} `]j:''K  
~ ^*;#[<  
nj
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System.err.println("文件下载结束！"); .^V9XN{'a  
} l#fwNM/F  
catch(Exception e){e.printStackTrace ();} tFu"h1  
} nWFU8u%  
IM=3n%6  
;3Z6K5z*f  
//获得文件长度 %JPBD]&M  
public long getFileSize() XB;C~:  
{ $u%7]]Y^\  
int nFileLength = -1; {3eg4j.Z  
try{ fzZ`O{$8  
URL url = new URL(siteInfoBean.getSSiteURL()); D]+]Br8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); X{ f#kB]w  
httpConnection.setRequestProperty("User-Agent","NetFox"); L&hv:+3N  
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A8T8+M:  
int responseCode=httpConnection.getResponseCode(); K(}g!iT)~  
if(responseCode>=400) )6*)u/x:  
{ bE6bx6=u  
processErrorCode(responseCode); 'J_`
CS  
return -2; //-2 represent access is error $d5}OI"g  
} wf2v9.;X:<  
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String sHeader; Dy|)u1?  
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for(int i=1;;i++) :
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{ ff5 e]^,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); CkR 95*  
//Utility.log(in.readLine()); Y+!z]S/x  
sHeader=httpConnection.getHeaderFieldKey(i); i)= \-C  
if(sHeader!=null) JVR,Py:%G  
{ HcCT=x7:  
if(sHeader.equals("Content-Length")) Ot;)zft  
{ Dbw{E:pq  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); D\^\_r):  
break; `rb}"V+  
} Zmz $ hr  
} 7UsU03  
else )8%m|v#W  
break; nd~O*-uYg  
} S
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} M`p[ Zq  
catch(IOException e){e.printStackTrace ();}  w\y)  
catch(Exception e){e.printStackTrace ();} "Pa  y2  
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Utility.log(nFileLength); Y|cj&<o  
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return nFileLength; om2)Cd9~7  
} E7 P'}  
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//保存下载信息（文件指针位置） A,4Z{f83  
private void write_nPos() -+y3~^EYm,  
{ 22@w:  
try{ AmB*4p5b  
output = new DataOutputStream(new FileOutputStream(tmpFile)); WSbD."p<  
output.writeInt(nStartPos.length); [oOV@GE  
for(int i=0;i<nStartPos.length;i++) a/xnf<(H  
{ N#GMvU
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// output.writeLong(nPos); 5#~E[dr  
output.writeLong(fileSplitterFetch.nStartPos); <-"[9 w  
output.writeLong(fileSplitterFetch.nEndPos); w+gPU1|(r  
} KJ cuZ."wX  
output.close(); 4}NCdGD  
} Qrw:
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catch(IOException e){e.printStackTrace ();} MG vp6/Pd  
catch(Exception e){e.printStackTrace ();} 5M\bH'1  
} v]y=+* A  
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//读取保存的下载信息（文件指针位置） Y_/w}HB   
private void read_nPos() uZa)N-=b2  
{ h-6x! 6pm  
try{ v+C%t!dx  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0t%`jY~%  
int nCount = input.readInt(); upiYo(sN.  
nStartPos = new long[nCount]; 7M<co,"  
nEndPos = new long[nCount]; C(n_*8{  
for(int i=0;i<nStartPos.length;i++) a xz-H`oq4  
{ RG:_:%@%}  
nStartPos = input.readLong(); #6@4c5{2=4  
nEndPos = input.readLong(); \G2PK&)F  
} ]/7#[  
input.close(); > 1=].  
} t'[`"pp=  
catch(IOException e){e.printStackTrace ();} ~z'Y(qG  
catch(Exception e){e.printStackTrace ();} :{%~L4$HI  
} (
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private void processErrorCode(int nErrorCode) ")9jt
^  
{ H3+P;2{  
System.err.println("Error Code : " + nErrorCode); A`*Sx"~jdx  
} :@~mN7O*  
byPqPSY  

|%@pjJ`3  
//停止文件下载 P52qtN<  
public void siteStop() Sb^o`~ Eh  
{ ^1bM=9]F0  
bStop = true; XA\wZV |{  
for(int i=0;i<nStartPos.length;i++) ?u>A2Vc!  
fileSplitterFetch.splitterStop(); %*OQH?pyx}  
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} ]v l?
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} e17]{6y  
//负责部分文件的抓取 NmTo/5s  
**FileSplitterFetch.java ZQAiuea  
*/ vG~JK[  
package NetFox; s#FX2r3=Fg  
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import java.io.*;  CP
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import java.net.*; Va^(cnwa  
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public class FileSplitterFetch extends Thread { .9q`Tf  
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String sURL; //File URL Z GrDa  
long nStartPos; //File Snippet Start Position V`}u:t7r  
long nEndPos; //File Snippet End Position @zT2!C?^L  
int nThreadID; //Thread's ID }$#PIyz  
boolean bDownOver = false; //Downing is over c]NZGn*  
boolean bStop = false; //Stop identical 1cD  
FileAccessI fileAccessI = null; //File Access interface ~)*uJ wW/a  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException i<*W,D6  
{ meZZQ:eSl  
this.sURL = sURL; KgXu x-q  
this.nStartPos = nStart; k0,]2R  
this.nEndPos = nEnd; ;_m;:<  
nThreadID = id; V!QC.D<  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 { T?1v*.[  
} 8zQN[[#n  
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public void run() E+J+fi  
{ E
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while(nStartPos < nEndPos && !bStop) |OIU)53A-  
{ Se>v|6  
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try{ p MR4]G  
URL url = new URL(sURL); #
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); WTu!/J<\  
httpConnection.setRequestProperty("User-Agent","NetFox"); dte-2?%~j  
String sProperty = "bytes="+nStartPos+"-"; lD$\t/8B  
httpConnection.setRequestProperty("RANGE",sProperty); ,,G'Zur7  
Utility.log(sProperty); s3=slWY=  
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@ X5#?  
InputStream input = httpConnection.getInputStream(); ~'N+O K  
//logResponseHead(httpConnection); )gV @6w  
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byte[] b = new byte[1024]; 1i;Cw/mr  
int nRead; ptlag&Z  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )1f.=QZN^;  
{ AsR}qqG  
nStartPos += fileAccessI.write(b,0,nRead); Wz;@Rl|F  
//if(nThreadID == 1) y 7z)lBy\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %`lLX/4~  
} 2yVQqwQm  
(V0KmNCW`  
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Utility.log("Thread " + nThreadID + " is over!"); 6uxF<  
bDownOver = true; xW58B  
//nPos = fileAccessI.write (b,0,nRead); U5[r&Y D  
} W Haf}.
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catch(Exception e){e.printStackTrace ();} AI-ZZ6lzR  
} Qe`Nb4xf  
} b^"mQ  
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g|M>C:ZT  
//打印回应的头信息 q siV  
public void logResponseHead(HttpURLConnection con) z&z5EtFUTh  
{ ,r;E[k@  
for(int i=1;;i++)  p]jG ,S  
{ K4b2)8  
String header=con.getHeaderFieldKey(i); g`4WisL1n  
if(header!=null) bjq.nn<=  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); \_7'f  
Utility.log(header+" : "+con.getHeaderField(header)); ' ?a d  
else O;.DQ  
break; " "S&zN  
} B5[As8
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} M-(,*6Q  
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public void splitterStop() _)6r@fZ.p  
{ r(<91~Ww  
bStop = true; 3gv?rJV  
} r9p ((ir  
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8  
} O~Svk'.)  
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/* CKX3t:HP0  
**FileAccess.java d"S\j@  
*//文件访问(定位，写) _p<wATv?7t  
package NetFox; %&wi@ *#  
import java.io.*; :0p$r pJP  
HC"yC;_  
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v59  
public class FileAccessI implements Serializable{ [-^xw1:  
;X+cS,h  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 O7p=|F"  
RandomAccessFile oSavedFile; oo1h"[  
long nPos; QN#tj$x  
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n{=Ot^ ";  
public FileAccessI() throws IOException /< Dtu UM  
{ ?y,KN}s_  
this("",0); [_*?~  
} l0E]#ra"  
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fsWPU]\)  
public FileAccessI(String sName,long nPos) throws IOException zek>]l`!  
{ oAvLSFn  
oSavedFile = new RandomAccessFile(sName,"rw"); eTI?Mu>C  
this.nPos = nPos; ()<?^lr33  
oSavedFile.seek(nPos); lInf,Q7W  
} i0~Af`v  
$p*.[)  
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public synchronized int write(byte[] b,int nStart,int nLen) ~6{U^3  
{ gCbS$Pw  
int n = -1; sIRfC< /P  
try{ )GOio+{H  
oSavedFile.write(b,nStart,nLen); =+H,}  
n = nLen; Dy{lgT0k  
} :W$-b  
catch(IOException e) -
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{ 2`Ihrz6  
e.printStackTrace (); ViU5l*n;  
} <:!:7  
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Lc
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return n; [{zf
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} BY@l:y4  
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} zX6Q7Bc  
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/* f[?JLp   
**SiteInfoBean.java @0%[4  
*/ (~fv;}}v  
package NetFox; ep{/m-h(!_  
xRZ/[1f!  
 h
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public class SiteInfoBean { H`jnChD:M'  
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private String sSiteURL; //Site's URL i;\n\p1  
private String sFilePath; //Saved File's Path NTVaz.  
private String sFileName; //Saved File's Name Z_mQpt|y  
private int nSplitter; //Count of Splited Downloading File I/u>
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public SiteInfoBean() yTf/]H]d  
{//nSplitter的缺省值为5 vi` VK&+r  
//default value of nSplitter is 5 J|([(  
this("","","",5); H%0WD_  
} yi2F#o 'K  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) gw$?&[wY  
{ arvKJmD  
sSiteURL= sURL; R:[#OH.c  
sFilePath = sPath; H#G3CD2&  
sFileName = sName; 7c8`D;A-K  
this.nSplitter = nSpiltter; y[GqV_~?Y  
#VxN [770  
<`NtTG  
} @?gRWH;Pq  
b"Jr_24t3v  
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public String getSSiteURL() &AVX03P  
{ i?,\>LTG  
return sSiteURL; .R^ R|<x  
} iu2O/l#r  
Z:diM$Z?7  
d+"
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public void setSSiteURL(String value) cv. j  
{ m%c]+Our`  
sSiteURL = value; 5x!rT&!G  
} yh'*eli  
-J0I2D  
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public String getSFilePath() g'2}Y5m$`  
{ @.,'A[D!K  
return sFilePath; +wZ|g6vMct  
} =&~ K;=:  
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V(Cxd.u  
public void setSFilePath(String value) 2nCHL'8N  
{ w|4CBll  
sFilePath = value; 4}Lui9  
} e}(8BF  
,l.+$G  
9%riB/vkrF  
public String getSFileName() S'`RP2P  
{ ,rOh*ebF  
return sFileName; :d~mlyFI6P  
} uc LDl  
\\{78WDA  
 O`Htdnu  
public void setSFileName(String value) t{`uN  
{ zoBp02j  
sFileName = value; r4fd@<=g  
} g[;&_gL  
;u<F,o(  
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public int getNSplitter() X^i3(N  
{ vzF6e eaD  
return nSplitter; v~0lZe  
} :*-O;Yw?S@  
!uA'0U?ky  
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public void setNSplitter(int nCount) +~7[T/v+n  
{ [8vqw(2Tm(  
nSplitter = nCount; =FMrVE  
} Z7 ++c<|p  
} b,47 EJ}  
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Jg$ NYs.xZ  
/* TN/&^/  
**Utility.java /K;AbE  
*/ -6^Ee?"  
package NetFox; ony;U#^T  
pP%+@;  
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public class Utility { ?P}) Qa  
X>Z83qV5d!  
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public Utility() Z/;hbbG  
{ ;KG}Yr72  
"9Br)3  
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} )iZhE"?z  
zLPCWP.u  
//线程睡眠 c~d*SDca  
public static void sleep(int nSecond) yr)e."#S  
{ 
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try{ H~:g=Zw  
Thread.sleep(nSecond); V'9OGn2v  
} slLTZ]  
catch(Exception e) e.(RhajB  
{ ~8'HX*B]z  
e.printStackTrace (); |
1Nz8Vr.  
} ^5+7D1>W%  
} iphdJZ/f  
%v^qQWy=*  
//日志 k"cKxzB  
public static void log(String sMsg) G$~hAZ  
{ Y"dTm;&  
System.err.println(sMsg); k1LbWR1%wB  
} hJX;/~L  
% QaWg2Y=  
R^.c  
public static void log(int sMsg) /q!_f!<q4x  
{ EPM(hxCIQ  
System.err.println(sMsg); S-brV\v7  
} buHUBn[3)  
} !H @nAz  
9~ifST\  
W7 +Q&4Y  
/* Z#K0a'  
**TestMethod.java Mi`t$hmP  
*/ _HAr0R8BY  
package NetFox; ke'OT>8  
}-&#vP~I  
^SS9BQ*m  
public class TestMethod { $:?=A5ttuo  
%F<3_#Y  
t'C9;  
public TestMethod() N
9z!-y'X  
{ ///xx/weblogic60b2_win.exe K81&BVx/  
try{ + Cq&~<B  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); eqpnh^0}d  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ^!O2Fw  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !V/p.O  
fileFetch.start(); X
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} *C>
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catch(Exception e){e.printStackTrace ();}
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! n?j)p.  
prxmDI  
} g$8aB{)  
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p\xsW"=8q  
public static void main(String[] args) /jOug>s  
{ =[Tf9uQY  
new TestMethod(); <"S/M]9  
} JZ-M<rcC  
} > 'JWW*Y!  
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