http断点续传简单实现（java)

/* + d)~;I$  
**SiteFileFetch.java nZ+5@( *  
*/ 92ww[+RQ@  
package NetFox; Saq>o.  
import java.io.*; Pisr&"A  
import java.net.*; bh6wI%8H  
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public class SiteFileFetch extends Thread { fU7:3"|s8  
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pXEVI6 }  
SiteInfoBean siteInfoBean = null; //文件信息Bean ~vZzKRVS  
long[] nStartPos; //开始位置 ;mKU>F<V  
long[] nEndPos; //结束位置 ]8nm9qmF<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 8VGXw;(Y,d  
long nFileLength; //文件长度 .-6s`C2 Y}  
boolean bFirst = true; //是否第一次取文件 l0 :xQV`  
boolean bStop = false; //停止标志 (G!J=
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File tmpFile; //文件下载的临时信息 A;HKR4p;8  
DataOutputStream output; //输出到文件的输出流 -t#a*?"$w  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） _ShJ3\,K  
public SiteFileFetch(SiteInfoBean bean) throws IOException `mTxtuid{  
{ =C2C~Xd  
siteInfoBean = bean; p<['FRf"  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); uKzz
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Z"KuS  
if(tmpFile.exists ()) <:t\P.  
{ qz SI cI  
bFirst = false; yC$7XSr=  
read_nPos(); )%c)-c  
} YAG3PWmD  
else >~InO^R`5  
{ <4bo7XH  
nStartPos = new long[bean.getNSplitter()]; k~F/Ho+R&  
nEndPos = new long[bean.getNSplitter()]; D4-U[l+K>  
} :m)?+  
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} h /Nt
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public void run() T ua @w+  
{ %c{)'X  
//获得文件长度 IGQ8-#=  
//分割文件 EHjhez  
//实例FileSplitterFetch vBXr[XoC  
//启动FileSplitterFetch线程 1nmWL0  
//等待子线程返回 t9{EO#o'k  
try{ DR=1';63  
if(bFirst) r&RSQHa)  
{ Yw `VL)v(y  
nFileLength = getFileSize(); ~`.%n7  
if(nFileLength == -1) w5\)di  
{ C(hg"_W ou  
System.err.println("File Length is not known!"); N*W.V,6yH  
} Lo4t:H&  
else if(nFileLength == -2) w:v:znQrW  
{ u>#'Y+7  
System.err.println("File is not access!"); ,Fiiw  
} 2Mp;/b!  
else (H^o8J   
{ /+YWp>6LU  
for(int i=0;i<nStartPos.length;i++) r>o6}Mx$  
{ SF7 Scd  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); RPwSo.c4
 
} /.bwwj_;  
for(int i=0;i<nEndPos.length-1;i++) ]ghPbS@  
{ s5e}X:  
nEndPos = nStartPos[i+1]; 0jH2.d=  
} g-36Q~`9v  
nEndPos[nEndPos.length-1] = nFileLength; ,88}5)b[  
} g=8e.Y*Fr  
} =j-{Mxb3  
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7dZ!GX?\y  
//启动子线程 .rHO7c,P~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; wC~Uy%  
for(int i=0;i<nStartPos.length;i++) IT|CfQ [D  
{ TzJN,]F!M  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !WXSrICX[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2z:9^a/]Na  
nStartPos,nEndPos,i); =9-c*bL  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &/p9+gd  
fileSplitterFetch.start(); l"/Os_4O  
} t*#T
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zuw6YY8kQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); w'C(? ?mH  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", `KN{0<Ne  
nEndPos = " + nFileLength); e!#:h4I  
// fileSplitterFetch[nPos.length-1].start(); 2cL<`  
#"l=Lv  
$v,_8{ !  
//等待子线程结束 ^
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//int count = 0; V!p;ME  
//是否结束while循环 [/FIY!nC?  
boolean breakWhile = false; A]1](VQ)4  
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while(!bStop) |yr
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{ I~,*Rgv/Z  
write_nPos(); Jc*A\-qC.  
Utility.sleep(500); L,$9)`j  
breakWhile = true; SX#ATf6#  
/KkUCq2A  
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for(int i=0;i<nStartPos.length;i++) 8Pq|jK "  
{ *:iFhKFU  
if(!fileSplitterFetch.bDownOver) \O56!,k  
{ t5S S]  
breakWhile = false; pV_2JXM~@  
break; /n_N`VJ7H  
} ;TY
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} K=V)"v5o3  
if(breakWhile) 0=NB[eG  
break; +NQw^!0qy  
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//count++; !"Kg b;A
 
//if(count>4) ;tO(,^  
// siteStop(); *&7Av7S  
} ne%ckW?ks  
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System.err.println("文件下载结束！"); uXXwMc<p  
} HghNI  
catch(Exception e){e.printStackTrace ();} \%UA6uj  
} <3'r&ks  
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I<DS
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//获得文件长度 !I@"+oY<  
public long getFileSize() >#SQDVFf  
{ KdUmet
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int nFileLength = -1; |VIBSty2d  
try{ #8cY,%<S]  
URL url = new URL(siteInfoBean.getSSiteURL()); R4{2+q=0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); e tY9Pq  
httpConnection.setRequestProperty("User-Agent","NetFox"); t ;(kSg.  
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int responseCode=httpConnection.getResponseCode(); A>Js`s  
if(responseCode>=400) _&P![o
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{ 7cH[}v`pn  
processErrorCode(responseCode); 5TqX;=B  
return -2; //-2 represent access is error F]xo*  
} D3$}S{Yw1  
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M   
String sHeader; 0Db#W6*^  
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for(int i=1;;i++) \f.ceh;!  
{ !h4L_D0  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); j*xxOwf  
//Utility.log(in.readLine()); 5P [b/.n  
sHeader=httpConnection.getHeaderFieldKey(i); iXeywO2nP  
if(sHeader!=null) ?Jio9Zr  
{ 7*`cWT_X  
if(sHeader.equals("Content-Length")) pPUKx=d  
{ H1]G<N3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ZBi|BD  
break; 7EO/T,{a  
} Vv#|%^0  
} $ba3dqbCW  
else a~jM^b;VN  
break; @Pb!:HeJE  
} Hn+w1v&3  
} _ 7X0  
catch(IOException e){e.printStackTrace ();} Q
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catch(Exception e){e.printStackTrace ();} C;QIp6"1  
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Utility.log(nFileLength); ]X%T^3%G  
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return nFileLength; CvS}U%  
} gP:
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//保存下载信息（文件指针位置） !lpKZG  
private void write_nPos() }&M$  
{ q$7SJ.pF  
try{ =^#^Mq)  
output = new DataOutputStream(new FileOutputStream(tmpFile)); z)*7LI  
output.writeInt(nStartPos.length);
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for(int i=0;i<nStartPos.length;i++) R-5EztmLae  
{ K=nW|^  
// output.writeLong(nPos); J=Q?_$xb}  
output.writeLong(fileSplitterFetch.nStartPos); KG=h!]Meq  
output.writeLong(fileSplitterFetch.nEndPos); '[V}]Z>-  
} ]n _OQ)VO
 
output.close(); ]rU$0)VN  
} qD0sD2 x  
catch(IOException e){e.printStackTrace ();} 5'*v-l,[  
catch(Exception e){e.printStackTrace ();} av~dH=&=  
} M*6}#ST  
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//读取保存的下载信息（文件指针位置） &Cv0oi&B  
private void read_nPos() %+0 7>/  
{ 8Evon&G59  
try{ {\u=m>2U|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Y;n;7M<F  
int nCount = input.readInt(); ,z8<[Q-#  
nStartPos = new long[nCount]; 8y:c3jzP_  
nEndPos = new long[nCount]; vOMmsU F  
for(int i=0;i<nStartPos.length;i++) zPWJ=T@N  
{ "eRf3Q7w:  
nStartPos = input.readLong(); [R-&5 G!x  
nEndPos = input.readLong(); z;fi  
} =\uQGH  
input.close(); rsSE*(T t  
} `*Ar6  
catch(IOException e){e.printStackTrace ();} r92C^h0  
catch(Exception e){e.printStackTrace ();} t.
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}
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private void processErrorCode(int nErrorCode) #I]5)XT  
{ t>]wWYy  
System.err.println("Error Code : " + nErrorCode); {-FS+D`  
} ;ndsq[k>  
~x}/>-d  
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//停止文件下载 WcE{1&PXx  
public void siteStop() F?>rWP   
{ 8Df(|>mK  
bStop = true; %(72+B70R  
for(int i=0;i<nStartPos.length;i++) 8+gti*C?\  
fileSplitterFetch.splitterStop(); lL6bIjf  
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} ?=C?3R  
} Ry5/O?QL  
//负责部分文件的抓取 kZ^}  
**FileSplitterFetch.java Y%1J[W  
*/ vO2I"Y*\  
package NetFox; g`(' k5=  
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import java.io.*; ~Z ,b
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import java.net.*;
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public class FileSplitterFetch extends Thread { z?a<&`W  
W
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String sURL; //File URL z% ln
}  
long nStartPos; //File Snippet Start Position |(mr&7O  
long nEndPos; //File Snippet End Position =x8F!W}Bt<  
int nThreadID; //Thread's ID H*SEzVb  
boolean bDownOver = false; //Downing is over t")+L{  
boolean bStop = false; //Stop identical %j '_I\  
FileAccessI fileAccessI = null; //File Access interface !>%U8A  
jQrj3b.NC3  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 32DSZ0  
{ Y5J}*`[Mr  
this.sURL = sURL; `vkNp8|  
this.nStartPos = nStart; j\,HquTR  
this.nEndPos = nEnd; 0zSRk]i.f  
nThreadID = id; "K.XoG4|  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ,34|_  
} a!`b`r-4  
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public void run() i\4Qv"%  
{ q T16th[D  
while(nStartPos < nEndPos && !bStop) uVO*@Kj+  
{ me-:A:si  

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try{
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URL url = new URL(sURL); F4!,8)}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c&A;0**K,  
httpConnection.setRequestProperty("User-Agent","NetFox"); A5d(L4Q]a(  
String sProperty = "bytes="+nStartPos+"-"; 0SoU\/kUi  
httpConnection.setRequestProperty("RANGE",sProperty); ;n-)4b]\  
Utility.log(sProperty); V}leEf2'  
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InputStream input = httpConnection.getInputStream(); 2u0dn?9\  
//logResponseHead(httpConnection); q&eUw<(F  
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byte[] b = new byte[1024]; ZBDEE+8e  
int nRead; hq5=>p  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) /xK5%cE>B  
{ fz)i9D@  
nStartPos += fileAccessI.write(b,0,nRead); ##%R|P3  
//if(nThreadID == 1) m,zZe}oJ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); wm3fd7T  
} ?[[K6v}q{  
j( *;W}*^  
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Utility.log("Thread " + nThreadID + " is over!"); 9fWr{fx  
bDownOver = true; $gYy3y  
//nPos = fileAccessI.write (b,0,nRead); won(HK\1p  
} ELF,T(  
catch(Exception e){e.printStackTrace ();} kg2?IL  
} NNWbbU3wjh  
} tDuQ+|~M  
$(2c0S{1  
ObDcNq/b!  
//打印回应的头信息 _$OhV#LKG  
public void logResponseHead(HttpURLConnection con) PB !\r}Q  
{ {.W$<y (j7  
for(int i=1;;i++) ;pU#3e+P8  
{ By3/vb)M5  
String header=con.getHeaderFieldKey(i); !}sYPz]7!  
if(header!=null) ~I0I#_$'P  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); u8Ul +u  
Utility.log(header+" : "+con.getHeaderField(header)); %4Nq T  
else O5PCR6U  
break; X&^8[,"  
} F,CQAgx  
} >x%Z^U  
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public void splitterStop() {5+t\~q$  
{ MSPzOJQPy  
bStop = true; jW6~^>S  
} (h0i2>K  
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} e_6@oh2s-  
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/* $'}:nwq6x  
**FileAccess.java X*F#=.lh  
*//文件访问(定位，写) 89F^I"Im(  
package NetFox; YQ>M&lnQ<  
import java.io.*; NQq$0<7.=W  
CT6Ca,  
#!\g5 ')mC  
public class FileAccessI implements Serializable{ a;AvY O  
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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 A{Giz&p  
RandomAccessFile oSavedFile; %WrUu|xj>_  
long nPos; 8W?/Sg`  
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public FileAccessI() throws IOException u"-q"0
 
{ e:IUO1#  
this("",0); ysA~Nq@  
} ' jFSv|g+0  
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public FileAccessI(String sName,long nPos) throws IOException U/E M(y  
{ |yiM7U,i  
oSavedFile = new RandomAccessFile(sName,"rw"); #_{3W-35*  
this.nPos = nPos; d^X;XVAvP  
oSavedFile.seek(nPos); I.I:2Ew+  
} xZt]s3?  
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public synchronized int write(byte[] b,int nStart,int nLen) X b-q:{r1h  
{ %fMK^H8{  
int n = -1; o Y_(UIa  
try{ uW!',"0ER  
oSavedFile.write(b,nStart,nLen); l)`bm/k]V  
n = nLen; W:8_S%~d  
} [;II2[5 ,  
catch(IOException e) g*Nc+W](P>  
{ 6=2M[T  
e.printStackTrace (); ,EW-21  
} xuQ$67F`;z  
AQ 3n=Lr   
xlF$PpRNM  
return n; C5#3c yf*B  
} Da5Zz(  
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} cP63q|[[  
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; k{w@L.@  
/* 0 } uEM_a  
**SiteInfoBean.java :P<} bGN  
*/ j K?GB  
package NetFox; x3O$eKy\|5  
/>_Mz  
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public class SiteInfoBean { U
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private String sSiteURL; //Site's URL F,Ec
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private String sFilePath; //Saved File's Path Am&/K\O  
private String sFileName; //Saved File's Name SU9qF73Y  
private int nSplitter; //Count of Splited Downloading File =xScHy{$  
'S\YNLqQ  
(D F{l?4x-  
public SiteInfoBean() poj@G{  
{//nSplitter的缺省值为5 f.cIhZF  
//default value of nSplitter is 5 szN`"Yi){  
this("","","",5); vBAds  
} =FQ]eb*  
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((F[]<?  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _P.+[RS@  
{ z8FeL5.(  
sSiteURL= sURL; (5rH72g(  
sFilePath = sPath; FI{9k(  
sFileName = sName; H5uWI  
this.nSplitter = nSpiltter; pJ-/"Q|:i  
DZKVZ_q  
6=a($s!   
} !fUrDOM0E  
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public String getSSiteURL() +[M5x[[$  
{ 67Rsd2   
return sSiteURL; *.4;7#  
} e8O[xM  
n.P$7%G`2  
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public void setSSiteURL(String value) :[P>e ox  
{ 1"ko wp  
sSiteURL = value; 'eg?W_zu  
} X+"8yZz3?  
;hU56lfZ)X  
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public String getSFilePath() Vvu+gP'z.  
{ ]etLobV  
return sFilePath; ;=.VKW%U  
} ?zp@HSa9  
](c[D9I!8  
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public void setSFilePath(String value) +Z[(s!  
{ EdxTaR  
sFilePath = value; P[-2^1P
"  
} }<`Mn34@  
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public String getSFileName() 7RNf)nz  
{ 4Sv&iQ=vh  
return sFileName; 2}:scag  
} \:ntqj&A|  
+V*FFv  
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public void setSFileName(String value) tkU"
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{ OV ~|@{6T  
sFileName = value; *fVs|  
} fwB+f`w`  
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Cn4o^6?"  
public int getNSplitter() }wzU<(Rx  
{ E ?(+v  
return nSplitter; ukBj@.~  
} 6Ouy%]0$I3  
o<2H~2/  
~9#[\/;"  
public void setNSplitter(int nCount) GGHe{l  
{ RGy4p)z*+  
nSplitter = nCount; ':
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} (.Yt| "j  
} c%Ht; sK`*  
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t.B%7e  
/* $8#zPJR&  
**Utility.java s\g"~2+  
*/ ]h8[b9$<")  
package NetFox; @mM'V5
_#  
7+';&2M)n~  
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public class Utility { sE7!U|  
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public Utility() "F%w{bf  
{ +:@HJXwK  
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} 6FuZMasr*  
!_<zK:`-L  
//线程睡眠 p<IMWe'tP  
public static void sleep(int nSecond) 8/cD7O  
{ mk#xbvvG  
try{ h ,;f6  
Thread.sleep(nSecond); e\%emp->  
} ~_^#/BnAl  
catch(Exception e) Lk{ES$  
{ $w{!}U2+-  
e.printStackTrace (); & yFS  
} hd*bPj;  
} -m*
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2u
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//日志 P)bS ;w\(Y  
public static void log(String sMsg) E
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{ yxq+<A4,a  
System.err.println(sMsg); ;w,+x 7  
} <:=}1t.Z  
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L
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public static void log(int sMsg) +RLHe]9&  
{ y>}dKbCN  
System.err.println(sMsg); p^1s9CM%  
} f4F13n_0X  
} owYf1=G  
IK~'ke  
R:49Gn:F  
/* -90qG"@  
**TestMethod.java V2-fJ!  
*/ + ;u<tA  
package NetFox; &|rh~;:jUX  
<)01]lKH  
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public class TestMethod { ('yBIb\ue  
AWkXWl}  
Fy(-.S1  
public TestMethod() .~J}80a/  
{ ///xx/weblogic60b2_win.exe AC*> f&  
try{ 8^bc4(H  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?"oW1a\  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); t+C9QXY  
SiteFileFetch fileFetch = new SiteFileFetch(bean); v
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fileFetch.start(); Vgzw['L}  
} ')!+>b(P  
catch(Exception e){e.printStackTrace ();} 3q +C8_:  
)3h%2C1uM  
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} A6D.bJ)  
Z/#l~.o[  
""LCyKu   
public static void main(String[] args) {J_1.uN=  
{ p'# (^  
new TestMethod(); cb ICO  
} f+*wDH  
} GTvp)^h  
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