http断点续传简单实现（java)

/* `
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**SiteFileFetch.java uD{ xs  
*/ v7#|%  
package NetFox; v&]yzl  
import java.io.*; ~>0H k}Hv  
import java.net.*; i tk/1  
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public class SiteFileFetch extends Thread { 4qsxlN>4O
 
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SiteInfoBean siteInfoBean = null; //文件信息Bean Y2dml!QM  
long[] nStartPos; //开始位置 {%y|
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long[] nEndPos; //结束位置 $[7/~I>m  
FileSplitterFetch[] fileSplitterFetch; //子线程对象
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long nFileLength; //文件长度 w?N>3`Jnf  
boolean bFirst = true; //是否第一次取文件 ,PJC FQMR  
boolean bStop = false; //停止标志 bt.3#aj  
File tmpFile; //文件下载的临时信息 <1*\ ~CX  
DataOutputStream output; //输出到文件的输出流 <X& fs*x&  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） alNn(0MG  
public SiteFileFetch(SiteInfoBean bean) throws IOException VUHf-bKl  
{ !V/7q'&t=  
siteInfoBean = bean; 4UzXTsjM7  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); f:~$x  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5e7\tBab  
if(tmpFile.exists ()) A9"!=/~  
{ Bx$?*y&f!v  
bFirst = false; `GCK%evLG  
read_nPos(); mD
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} bF+j%=  
else |68/FJZ,5  
{ pm:-E(3#  
nStartPos = new long[bean.getNSplitter()]; eU e, P  
nEndPos = new long[bean.getNSplitter()]; b+hN\/*]  
} ~kDJ-V  
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} &k-NDh3  
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public void run() F8Mf,jnPs  
{ #qD[dC$[t  
//获得文件长度 ]\L+]+u~  
//分割文件 ];b+f@  
//实例FileSplitterFetch V3d$C&<(  
//启动FileSplitterFetch线程 fH:S_7i  
//等待子线程返回 X6qgApyE  
try{ DUF$-'A  
if(bFirst) UA]fKi  
{ ~3f|-%Z  
nFileLength = getFileSize(); ji.?bKqHE  
if(nFileLength == -1) EN}XIa>R  
{ tXZMr  
System.err.println("File Length is not known!"); )/~o'M3  
} ]fU&?z#  
else if(nFileLength == -2) H~>8q~o]  
{ 9nFWJn  
System.err.println("File is not access!"); KH=
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} DxpJP,wY3  
else Y3(I;~$!  
{ yaWY>sB  
for(int i=0;i<nStartPos.length;i++) +*Uv+oC|  
{ KU+\fwYpnk  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ;)P=WS:=  
} %f1IV(3Qc  
for(int i=0;i<nEndPos.length-1;i++) 4*5e0:O  
{ ZW0\_1  
nEndPos = nStartPos[i+1]; _Rkvg-  
} Em5,Zr_  
nEndPos[nEndPos.length-1] = nFileLength; ;c DMcKKIA  
} (~E-=+R[$&  
} oGl<i  
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//启动子线程 [/VpvQ'  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;$gV$KB:xA  
for(int i=0;i<nStartPos.length;i++) .9,x_\|G*  
{ T{"Ur:p  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4gNN "  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;FF+uK  
nStartPos,nEndPos,i); a l6y=;\jZ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); e5n]@mu%  
fileSplitterFetch.start(); hiA\~}sl n  
} )|k#cT{=M  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0( A  ?&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); wAX;)PLg  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", k.o8!aCm  
nEndPos = " + nFileLength); {x_cgsn  
// fileSplitterFetch[nPos.length-1].start(); M6^ \LtFt  
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//等待子线程结束 o^*:  
//int count = 0; H)"]I3  
//是否结束while循环 S4{vS?>j  
boolean breakWhile = false; /~f[>#  
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while(!bStop) =s]2?m  
{ -o`K/f}d  
write_nPos(); 7Hgn/b[?b  
Utility.sleep(500); 0j6b5<Gpc*  
breakWhile = true; c ^.^5@  
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for(int i=0;i<nStartPos.length;i++) j%-Ems*H  
{ vcp{Gf|^  
if(!fileSplitterFetch.bDownOver) fHEIys,{  
{ 8#Z)qQWi_t  
breakWhile = false; ]BjYUTNm  
break; 8]`s&d@GY  
} 9lR6:}L7  
} p5vQ.Ni*\-  
if(breakWhile) g'7\WQ  
break; "5 ~{  
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//count++; F+Qnf'at1  
//if(count>4) e7{6<[k3+$  
// siteStop(); 3C%|src  
} b|DU  
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System.err.println("文件下载结束！"); r"h09suZBW  
} Z$KyK.FUU  
catch(Exception e){e.printStackTrace ();} FZ+2{wIV^  
} W,Q>3y
*
 
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//获得文件长度 rA B=H*|6  
public long getFileSize() wbKJ:eWgt  
{ [7gz?9VyLF  
int nFileLength = -1; xW5`.^5  
try{ [m h>N$  
URL url = new URL(siteInfoBean.getSSiteURL()); `^hA&/1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Oy=0Hsh@x  
httpConnection.setRequestProperty("User-Agent","NetFox"); iJOG"gI&  
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int responseCode=httpConnection.getResponseCode(); 50-7L,  
if(responseCode>=400) tugIOA  
{ -
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processErrorCode(responseCode); C
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return -2; //-2 represent access is error yx-"&K=`  
} :LNZC,-f}5  
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String sHeader;  =5B5  
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for(int i=1;;i++) qg`ae  
{ Zn r4^i&(  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 6:B,ir _  
//Utility.log(in.readLine()); ]J!#"m-]  
sHeader=httpConnection.getHeaderFieldKey(i); {Hl(t$3V`  
if(sHeader!=null) U= f9b]Y  
{ h~Z &L2V  
if(sHeader.equals("Content-Length")) @Q2E1Uu%  
{ 1) 2-UT  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); V )oXJL  
break; f['lY1#V1  
} 6c-'CW  
} =lk'[P/p`  
else $A{$$8P  
break; s-Yu(X2  
} <|Lz#iV37  
} [u K,.G  
catch(IOException e){e.printStackTrace ();} UV}:3c6ZX  
catch(Exception e){e.printStackTrace ();} :M{ )&{D  

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Utility.log(nFileLength); cRr3!<EZ  
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return nFileLength; W?4:sLC#3  
} ,z#D[5
  
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3-:^mRPJ  
//保存下载信息（文件指针位置） Ar/P%$Zfq  
private void write_nPos() 7ixG{yu  
{ 0Q7<;'m  
try{ p7`9 d1n  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )hO%W|  
output.writeInt(nStartPos.length); Eb9h9sjv  
for(int i=0;i<nStartPos.length;i++) ?_AX;z  
{ '\8YH+%It  
// output.writeLong(nPos); CckfoJ 9  
output.writeLong(fileSplitterFetch.nStartPos); "OI$PLK  
output.writeLong(fileSplitterFetch.nEndPos); LXby(|<j  
} wn_ >Vi1  
output.close(); a9NuYYr,h  
} x<!]#**;  
catch(IOException e){e.printStackTrace ();} }15&<s  
catch(Exception e){e.printStackTrace ();} jA:'P~`Hj  
} p.(+L^-=  
*: FS/ir  
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//读取保存的下载信息（文件指针位置） [
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private void read_nPos() 6%6dzZ  
{ o!+'<IQ'  
try{ BRu}"29  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); m2(}$z3e  
int nCount = input.readInt(); H*<E5^#dw  
nStartPos = new long[nCount]; gfAWN  
nEndPos = new long[nCount]; _ti^i\8~  
for(int i=0;i<nStartPos.length;i++) 7#UJ444b~  
{ RZpjr !R  
nStartPos = input.readLong(); hC<E4+5.,  
nEndPos = input.readLong(); mpwh=  
} {_\dwe9  
input.close(); z@19gD#8  
} 4|\M`T  
catch(IOException e){e.printStackTrace ();} u|$HA>F[  
catch(Exception e){e.printStackTrace ();} ShV_8F z  
} Lhg  
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private void processErrorCode(int nErrorCode) *< fJgc"3  
{ 5WfZd  
System.err.println("Error Code : " + nErrorCode); CL5^>.}  
} "-Nyf  
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//停止文件下载 q*4@d)_&  
public void siteStop() 'Tqusr>lPY  
{ p
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bStop = true; `]GL3cIh:  
for(int i=0;i<nStartPos.length;i++) %|JL=E}%|  
fileSplitterFetch.splitterStop(); V:5aq.o!  
};9/J3]m  
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} A9ld9R  
} 9{SzE /[  
//负责部分文件的抓取 1l^[%0  
**FileSplitterFetch.java v?3xWXX,  
*/ o\Fv~^  
package NetFox; W4nn)qBrh  
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import java.io.*; IR2Qc6+{  
import java.net.*; CcV@YST?  
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public class FileSplitterFetch extends Thread { MoiRAO  
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String sURL; //File URL ia /#`#.  
long nStartPos; //File Snippet Start Position QjpJIw  
long nEndPos; //File Snippet End Position _RzoXn{1e  
int nThreadID; //Thread's ID Imzh`SI,  
boolean bDownOver = false; //Downing is over a ge8I$*`@  
boolean bStop = false; //Stop identical I=[09o  
FileAccessI fileAccessI = null; //File Access interface JCZ&TK  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException dKDCJt]t  
{ W>{&" 5  
this.sURL = sURL; >N`, 3;Z  
this.nStartPos = nStart; c-.F{~  
this.nEndPos = nEnd; "[z/\l8O  
nThreadID = id; 3ErV" R4"$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 N@'l:N'f4  
} (A}c22qe  
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public void run() {~g7&+9x*
 
{ Ae^4  
while(nStartPos < nEndPos && !bStop) =7:}/&  
{ P$ b5o  
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try{ i8EK
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URL url = new URL(sURL); 0@u{(m  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~_ovQ4@  
httpConnection.setRequestProperty("User-Agent","NetFox"); }p)a7xn}  
String sProperty = "bytes="+nStartPos+"-"; :m'(8s8  
httpConnection.setRequestProperty("RANGE",sProperty); Bv*VNfUm  
Utility.log(sProperty); %%wngiz\  
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InputStream input = httpConnection.getInputStream(); 9/&1lFKJ  
//logResponseHead(httpConnection); RJT55Rv{  
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byte[] b = new byte[1024]; *z~
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int nRead; 4 #lLC-k  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) & }"I!  
{ [5b[ztN%  
nStartPos += fileAccessI.write(b,0,nRead); 3XbFg%8YG  
//if(nThreadID == 1) Fghan.F  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !HXsxNe  
} >A6PH*x  
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Utility.log("Thread " + nThreadID + " is over!"); )J[Ady^5  
bDownOver = true; .'-t>(}v  
//nPos = fileAccessI.write (b,0,nRead); vKkvB;F41  
} [c=![*}/  
catch(Exception e){e.printStackTrace ();} &XhxkN$8  
} 0
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} 5rA>2<\pQ  
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//打印回应的头信息 `I|Y7GoUO  
public void logResponseHead(HttpURLConnection con) fv>Jn`  
{ * _,yK-et  
for(int i=1;;i++) dftX$TS  
{ `\BBdQ#bH  
String header=con.getHeaderFieldKey(i); 6p,}?6^  
if(header!=null) Fk`6 q
 
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :}v:=ck  
Utility.log(header+" : "+con.getHeaderField(header)); c Ct5m  
else hGUQdTNP  
break; u
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} 8h|~>v  
} ]HG>Og  
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public void splitterStop() ZU9RvtbKB  
{ 8Tc:TaL  
bStop = true; f+
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} L#_QrR6Sny  
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} `-rtU  
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/* 6HVGqx  
**FileAccess.java z-S8s2.Fd  
*//文件访问(定位，写) `3UvKqe  
package NetFox; ]RW*3X  
import java.io.*; <|a9r: [  
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public class FileAccessI implements Serializable{ -r{]9v2j  
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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 &G+:t)|S  
RandomAccessFile oSavedFile; \FyHIs  
long nPos; kr]_?B(r  
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public FileAccessI() throws IOException C2 !F  
{ `[f IK,  
this("",0); bgmOX&`G  
} |Gb~[6u   
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public FileAccessI(String sName,long nPos) throws IOException As#/ln$nE  
{ )|S!k\^A  
oSavedFile = new RandomAccessFile(sName,"rw"); ~eGtoEY  
this.nPos = nPos; Jz_`dLL^w  
oSavedFile.seek(nPos); qI\B;&hr(  
} V ;M'd@  
{Hxziyv~Y(  
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public synchronized int write(byte[] b,int nStart,int nLen) 
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{ N8]d0  
int n = -1; SjU0Xb)[  
try{ u O~MT7~[X  
oSavedFile.write(b,nStart,nLen); N5fMMi(O  
n = nLen; E`3[62C  
} Z9PG7h  
catch(IOException e) [i N}W5 m  
{ _5768G`P  
e.printStackTrace (); `"E<%$|ZQy  
} xTdh/}  
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return n; Y<`uq'V  
} Yg")/*!H  
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} 2ISnWzq;  
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/* qznd'^[  
**SiteInfoBean.java ?$X1X`@  
*/ 6imQjtI  
package NetFox; e_CgZ  
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public class SiteInfoBean { .AHww7  
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private String sSiteURL; //Site's URL Y-:{a1/RKo  
private String sFilePath; //Saved File's Path
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private String sFileName; //Saved File's Name 'd=B{7k@  
private int nSplitter; //Count of Splited Downloading File &r!*Y&  
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public SiteInfoBean() ^T/d34A;SP  
{//nSplitter的缺省值为5 w#`E;fN'  
//default value of nSplitter is 5 1C\[n(9  
this("","","",5); <al/>7z' O  
} 9mH/xP:y  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) PaYsn *{})  
{ 5J8U] :Y)  
sSiteURL= sURL; Qa=v }d-O  
sFilePath = sPath; *H,vqs\}y  
sFileName = sName; veh?oJi@  
this.nSplitter = nSpiltter; *4
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} '}NQ`\k  
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public String getSSiteURL() F2RU7o'f.  
{ |cCrLa2*-  
return sSiteURL; Aaq!i*y  
} x0_$,Tz@  
}*I:0"WH  
0 lsX~d'W  
public void setSSiteURL(String value) o72G oUfs  
{ \"@BZ.y
 
sSiteURL = value; DkGC+Dw  
} &]Q\@;]Aq  
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public String getSFilePath() V8.o}
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{ 8(c,b  
return sFilePath; Mm+kG'Z!S  
} 8P=z"y  
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public void setSFilePath(String value) t1)Qa(#]  
{ D|p`~(  
sFilePath = value; 2-*zevPiG=  
} Jx8?x#}  
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public String getSFileName() Cj x
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{ NiQ_0Y}  
return sFileName; Wq1%  
} +5:oW~ ;  
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public void setSFileName(String value) 3-5X^!C  
{ -_RMiGM?T  
sFileName = value; <Prz>qL$  
} nT.2HQ((Xg  
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pIy+3&\e;  
public int getNSplitter() !!4` #Z0+#  
{ D> |R.{  
return nSplitter; fYuz39#*  
} AF}6O(C~  
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~;A36M-[.  
public void setNSplitter(int nCount) vf+GC*f  
{ 2}P?N  
nSplitter = nCount; L`Lro:E?kL  
} OTNcNY  
} 1\_S1ZS  
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/* 9fyJw1  
**Utility.java "Y Z B@  
*/ {>E`Zf:  
package NetFox; &xG>"sJ  
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public class Utility { +&7D ;wj=  
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}  
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public Utility() u"*@k^}(  
{ '7UW\KEB[}  
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} mgk<PY  
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//线程睡眠 WxB}Uh  
public static void sleep(int nSecond) fP>*EDn@xg  
{ H +O7+=&  
try{ DRC2U%[  
Thread.sleep(nSecond); jW^@lH EU  
} ]\y:AkxhJ  
catch(Exception e) b'Scoa7@'  
{ tp-PE?  
e.printStackTrace (); ~9Nn8g6  
} gi|j! m  
} 06FBI?;|=  
aB6F<"L,  
//日志 >8$]g  
public static void log(String sMsg) e^?0uVxS1  
{ pDlU*&  
System.err.println(sMsg); =@F1J7  
} ?=X G#we  
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public static void log(int sMsg) $n30[P@p;  
{ 3_:J`xX(4  
System.err.println(sMsg); T(UPWsj  
} &\Es\qVSf  
} &R\t<X9 n  
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&&/2oP+z  
/* @j/UDM  
**TestMethod.java :`~;~g
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*/ k?%?EsR  
package NetFox; <<,YgRl2  
95 7C
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8.S&J6  
public class TestMethod { .Du-~N4\  
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public TestMethod() 8[zux4<m  
{ ///xx/weblogic60b2_win.exe 8<gYB$* S  
try{ :T62_cFG  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?pS,?>J f  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); sEQAC9M  
SiteFileFetch fileFetch = new SiteFileFetch(bean); #bz#&vt$  
fileFetch.start(); jA&ZO>4  
} 3oH.1M/  
catch(Exception e){e.printStackTrace ();} T}%8Vlt]  
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} k}xXja*  
e} =tUdDf  
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public static void main(String[] args) gLyXe,Jp  
{ `1AVw]k  
new TestMethod(); oa4{s&db-  
} \e89 >m  
} CK<Wba  
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