http断点续传简单实现（java)

/* *w'q   
**SiteFileFetch.java -TK|Y"  
*/ .# !'c  
package NetFox; Nl$gU3kL  
import java.io.*; ;o-\.=l  
import java.net.*; TbKP8zw{  
"}'8`k+d  
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public class SiteFileFetch extends Thread { ;gxN@%}@  
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SiteInfoBean siteInfoBean = null; //文件信息Bean VjA wn}eO  
long[] nStartPos; //开始位置 S+) l[0  
long[] nEndPos; //结束位置
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 6?1s`{yy  
long nFileLength; //文件长度 l)tTg+:  
boolean bFirst = true; //是否第一次取文件 Ie G7@  
boolean bStop = false; //停止标志 _DPB?)!x  
File tmpFile; //文件下载的临时信息 e5qrQwU  
DataOutputStream output; //输出到文件的输出流 ill-%OPeg  
P3>..fhoW  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） S3ab0JM  
public SiteFileFetch(SiteInfoBean bean) throws IOException 0`VD!_`  
{ H Z;ZjC*  
siteInfoBean = bean; w+Z--@\  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "*Lj8C3|n  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 8 3z'#  
if(tmpFile.exists ()) 5u2{n rc  
{ XKz;o^1a^  
bFirst = false; 1A7%0/K-]  
read_nPos(); lv<iJH\  
} .-SDo"K.h  
else g  ,/a6M  
{ ^%\)Xi  
nStartPos = new long[bean.getNSplitter()]; F[>7z3I  
nEndPos = new long[bean.getNSplitter()]; '}U_D:o.b  
} Q!4i_)rM  
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} U0NOU#  
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public void run() uL2"StW  
{ 1*C:hg@  
//获得文件长度 Zu\p;!e  
//分割文件 Q0pC4WJ`  
//实例FileSplitterFetch ?TvQ"Y}k  
//启动FileSplitterFetch线程 w{k1Y+1  
//等待子线程返回 1a7!4)\  
try{ u] F70C^~  
if(bFirst) Ni+3b  
{ I#"t'=9H  
nFileLength = getFileSize();
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if(nFileLength == -1) iP<k1#k  
{ >;&Gz-lm  
System.err.println("File Length is not known!"); |HrM_h<X  
} ;EgzC^2e  
else if(nFileLength == -2) `^v4zWDK  
{ S304ncS|M  
System.err.println("File is not access!"); u9TzZ  
} c u\ls^  
else Hu<p?mF#  
{ c5X`_  
for(int i=0;i<nStartPos.length;i++) E|pk
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{ {F'Az1^I=  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); .CVUEK@Z4  
} C@*%A
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for(int i=0;i<nEndPos.length-1;i++) +
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{ ?QGm
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nEndPos = nStartPos[i+1]; Uh>.v |P6  
} 1s Br.+p  
nEndPos[nEndPos.length-1] = nFileLength; A:kkCG!~Nf  
} HV ;;  
} N*~_\x  
#MUiL=  
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//启动子线程 tC2N>C[N  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ?$3r5sx  
for(int i=0;i<nStartPos.length;i++) {T&v2u#S  
{ Q4X7Iu:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,*7H|de7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #e*X0;m  
nStartPos,nEndPos,i); gF3TwA
r  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^Z2kq2}a  
fileSplitterFetch.start(); 2A*/C7
 
} ]pWP?Ws  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "9qp"%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |=\91fP68`  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", X:Q$gO?[4  
nEndPos = " + nFileLength); a'uU,Eb}#w  
// fileSplitterFetch[nPos.length-1].start(); &Cq{ _M  
z!:'V]  
s;J\Kc?"|  
//等待子线程结束 {DT4mG5  
//int count = 0; ;W0]66&  
//是否结束while循环 uArR\k(  
boolean breakWhile = false; MHo1 lrZa+  
>\ZR*CS  
71O3O7  
while(!bStop) E:FO_R(Xq  
{ NY@"&p'Q  
write_nPos(); "x&3Z@q7  
Utility.sleep(500); ?vu_k 'io  
breakWhile = true; %,|ztH/ Q  
t^.'>RwW|  
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for(int i=0;i<nStartPos.length;i++) vBNZ<L\|a  
{ }~Q5Y3]#~  
if(!fileSplitterFetch.bDownOver) 5
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{ _UkmYZ/  
breakWhile = false; )r9b:c\  
break; o 7G> y#Y  
} I]X  
} cOkgoL" 4  
if(breakWhile) c&f y{}10  
break; !%xP}{(7  
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<qhBc:kc  
//count++; .Pw%DZ'  
//if(count>4) yG&2UqX  
// siteStop(); S$eDnw~$  
} C0fmmI0z~  
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System.err.println("文件下载结束！"); B wC+o
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} JRO$<  
catch(Exception e){e.printStackTrace ();} pUCK-rL  
} (KTnJZ  
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//获得文件长度 |y"jZT6R}t  
public long getFileSize() ?z/Vgk+9|  
{ ,=o0BD2q  
int nFileLength = -1; e7xj_QH  
try{ ?} (=  
URL url = new URL(siteInfoBean.getSSiteURL()); =x0No*#|'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )`8pd 7<.  
httpConnection.setRequestProperty("User-Agent","NetFox"); F>+2DlA`<e  
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int responseCode=httpConnection.getResponseCode(); %6ub3PLw8  
if(responseCode>=400) =MLf[
 
{ >fzwFNdo  
processErrorCode(responseCode); sG,+  
return -2; //-2 represent access is error [$a<b/4  
} >t3'_cBC!  
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String sHeader; n.hElgkUOr  
59*M"1['Q  
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for(int i=1;;i++) M)!skU  
{ !QEL"iJ6M'  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^bUxLa[.  
//Utility.log(in.readLine());
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sHeader=httpConnection.getHeaderFieldKey(i); 7>i2OBkAhB  
if(sHeader!=null) NQ9Ojj{#  
{ w#(RW7":F  
if(sHeader.equals("Content-Length")) RY=1H  
{ b2kWjg.4  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 0oU=RbC  
break; 6)e5zKW!?  
} 4tXSYHd3  
} 1
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else [VSU"AJ
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break; EO)%UrWnC  
} +.Bmkim  
} &uM^0eM  
catch(IOException e){e.printStackTrace ();} 7Kf}O6nE  
catch(Exception e){e.printStackTrace ();} (~s|=Hxq|-  
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Utility.log(nFileLength); 8o-bd_  
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return nFileLength; [@"wd_f{l  
} Owf.f;QR  
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//保存下载信息（文件指针位置） TJy4<rb  
private void write_nPos() >dQK.CG  
{ Bct"X#W|&  
try{ N.j "S'(i  
output = new DataOutputStream(new FileOutputStream(tmpFile)); |(% u}V?  
output.writeInt(nStartPos.length); XnU
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for(int i=0;i<nStartPos.length;i++) `v nJ4*  
{ ~]uZy=P? 5  
// output.writeLong(nPos); D>sYPrf  
output.writeLong(fileSplitterFetch.nStartPos); V"RpH,  
output.writeLong(fileSplitterFetch.nEndPos); vtxvS3   
} |L:Cn J  
output.close(); zAScRg$:?  
} oq;'eM1,.  
catch(IOException e){e.printStackTrace ();} YaY8 `M{  
catch(Exception e){e.printStackTrace ();} {CUk1+  
} .T.5TMiOSq  
$.K?N@(W  
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//读取保存的下载信息（文件指针位置） H:S,\D?%2x  
private void read_nPos() <@,$hso7:  
{ K7`YJp`i  
try{ P $>`  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?tYpc_p
#  
int nCount = input.readInt(); UAYd?r  
nStartPos = new long[nCount]; :w-`PYJ%G  
nEndPos = new long[nCount]; Jb(Y,LO^  
for(int i=0;i<nStartPos.length;i++) 5/I_w0  
{ WDx Mo`zT  
nStartPos = input.readLong(); >n
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nEndPos = input.readLong(); KMjg;!y  
} Xm_$ dZ  
input.close(); smU4jh9S  
} G'#41>q+  
catch(IOException e){e.printStackTrace ();} jO'|mGUM  
catch(Exception e){e.printStackTrace ();} ]tt} #  
} 6*XM7'n  
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private void processErrorCode(int nErrorCode) &M"ouy Zo9  
{ wH6u5*$p  
System.err.println("Error Code : " + nErrorCode); \
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} F 3RB  
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3$p#;a:=n  
//停止文件下载 Utt>H@t[  
public void siteStop() i~yX tya  
{ (#Mp 5C'X  
bStop = true; ;b%{ilx:  
for(int i=0;i<nStartPos.length;i++) A7-r<s  
fileSplitterFetch.splitterStop(); <94G  
*\XH+/]+  
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} 8^yJ
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} .y4&rF$n  
//负责部分文件的抓取 .v`b[4M4  
**FileSplitterFetch.java e~\QE0Oe:  
*/ zlf}.  
package NetFox; mLwY]2T"  
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import java.io.*; }ot"Sx\.  
import java.net.*; d@kc[WLD^  
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public class FileSplitterFetch extends Thread { 5nLDj:C~  
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String sURL; //File URL <,8l *1C  
long nStartPos; //File Snippet Start Position ;j}y
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long nEndPos; //File Snippet End Position J !#Zi#8sF  
int nThreadID; //Thread's ID 0Xl%uF+w  
boolean bDownOver = false; //Downing is over +]!lS7nsW  
boolean bStop = false; //Stop identical /g.]RY+u|x  
FileAccessI fileAccessI = null; //File Access interface r6.N4eW.L  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException {]/8skov5]  
{ ,
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this.sURL = sURL; (H#M<N  
this.nStartPos = nStart; 8k!6b\Imz  
this.nEndPos = nEnd; =!.mGW-Q}  
nThreadID = id; tJZc/]%`H  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 n9UKcN-  
} .b>TK  
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public void run() sa#.l% #  
{ Z!{UWegun  
while(nStartPos < nEndPos && !bStop) S%6
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{ !{%G0(Dv  
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try{ %'ZN`XftG  
URL url = new URL(sURL); 4ke^*g K<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :7b-$fm  
httpConnection.setRequestProperty("User-Agent","NetFox"); Sp?NfJ\Ie  
String sProperty = "bytes="+nStartPos+"-"; Y E1Hpeb  
httpConnection.setRequestProperty("RANGE",sProperty); f(Hu {c5yV  
Utility.log(sProperty); yYTVXs`fVj  
w]!0<  
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InputStream input = httpConnection.getInputStream(); RQ' H!(K  
//logResponseHead(httpConnection); .9M
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byte[] b = new byte[1024]; Fdt}..H%  
int nRead; C1B'#F9EO  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) R]L2(' B  
{ {B{i(6C(  
nStartPos += fileAccessI.write(b,0,nRead); Ap<J'?~y  
//if(nThreadID == 1) HeIS;gfUY  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G$=-,6kZO  
} y-+G wa3  
@$U 
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Utility.log("Thread " + nThreadID + " is over!"); Z)9R9s  
bDownOver = true; %e=!nRc  
//nPos = fileAccessI.write (b,0,nRead); T\sNtdF`:  
} (B#(Z=  
catch(Exception e){e.printStackTrace ();} dOXD{c  
} x ^vt; $  
} Q7a(P  
?q$P>guH6-  
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//打印回应的头信息 !v>ew9  
public void logResponseHead(HttpURLConnection con) 6 =>G#  
{ ! D1zXXq  
for(int i=1;;i++) !nw[  
{ X"/~4\tJ"  
String header=con.getHeaderFieldKey(i); dWpk='  
if(header!=null) uqZ3Hyb  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ^gg!Me
 
Utility.log(header+" : "+con.getHeaderField(header)); 3|eUy_d3  
else \E hr@g  
break; Yj8&  
} dY'Y5Th~  
} JvJ;bFXD  
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e\N0@  
public void splitterStop() w}k B6o]  
{ ?r3e*qJGn  
bStop = true; "c Pz|~  
} QJXdb]Y^;  
8/q*o>[?  
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} !S,pR
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wn84?$BGd  
/* L@A9{,9Pl  
**FileAccess.java hqW$kw  
*//文件访问(定位，写) 'NjSu64W  
package NetFox; rPTfpeqN)  
import java.io.*; 0yQe5i}  
e
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public class FileAccessI implements Serializable{ PqfVX8/q0  
RKe?
.  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 [%~NM/xu<  
RandomAccessFile oSavedFile; .^H1\p];Lw  
long nPos; 'j#a%j@{  
A-0m8<  
4  
public FileAccessI() throws IOException 3- )kwy6L  
{ gA+YtU{z  
this("",0); 7}07Pit  
} v=MzI#0L  
Ar5JP_M`E  
:SeLkQC  
public FileAccessI(String sName,long nPos) throws IOException Tw}z7U"  
{ k4mTZ}6E  
oSavedFile = new RandomAccessFile(sName,"rw"); /cY[at
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this.nPos = nPos; y`+<X{V5L  
oSavedFile.seek(nPos); ^Kum%<[i  
} my=~"bw4  
#tP )-ww  
,whM22Af~{  
public synchronized int write(byte[] b,int nStart,int nLen) ,s8&#1rJ-  
{ skSNzF7'  
int n = -1; |{!Ns+'  
try{ |vT=Nnu  
oSavedFile.write(b,nStart,nLen); )#mW7m9M#  
n = nLen; U)b&zZc;  
} h%|9]5(=  
catch(IOException e) 7t+]z)  
{ o"f%\N0_8  
e.printStackTrace (); DW4MA<UQ  
} >:fJhF@  
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*IVD/9/  
return n; s'2y%E#  
} XSls]o s  
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@US '{hO1p  
} ~.!?5(AH8z  
,Zr YJ<  
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/* tTE3H_  
**SiteInfoBean.java n*Q4G}p  
*/ s}<)BRZi  
package NetFox; B##C{^5A`  
P'gT6*an,"  
v3!byN^  
public class SiteInfoBean { 5auL<Pq  
}]Qmt5'NI  
}% FDm@+  
private String sSiteURL; //Site's URL bmSpbX\  
private String sFilePath; //Saved File's Path <w%Yq?^  
private String sFileName; //Saved File's Name VQ
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private int nSplitter; //Count of Splited Downloading File *%z<P~}  
2>`m<&y  
+}`p"<'u  
public SiteInfoBean() ,2E`:#$  
{//nSplitter的缺省值为5 W[@"H1bVH  
//default value of nSplitter is 5 ?BXP}]  
this("","","",5); t>m8iS>  
} he_HVRpB  
d#RF0,Y9  
k-;.0!D^  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) o&*1U"6D  
{ {Nzmb|&  
sSiteURL= sURL; P]{B^,E  
sFilePath = sPath; z[_
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sFileName = sName; Y+}OClS  
this.nSplitter = nSpiltter; !#l0@3  
;e`D#k
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VuP#b'g=|]  
} HFpjNR  
k QB 1=c  
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public String getSSiteURL() &8IWDx.7}  
{ K[`4vsE  
return sSiteURL; -zkW\O[  
} 1nw$B[  
?Aj\1y4L1  
]JGKL5~p  
public void setSSiteURL(String value) E5v|SFD  
{ Xd90n>4S  
sSiteURL = value; l;"ub^AH  
} 7r:nMPX  
6C@0[Q\ER  
}UJdE#4  
public String getSFilePath() }7f 1(#{7  
{ ~`tJvUo0  
return sFilePath; )1X' W  
} weTK#O0@v  
z{7,.S u  
<VauJB*R  
public void setSFilePath(String value) PxdJOtI"  
{ :8p2Jxm  
sFilePath = value; bdNY7|j`  
} ;+aDjO2(  
z|oA{VxW>  
GN}9$:  
public String getSFileName() <S:,`v&Z  
{ t*ri`}a{v  
return sFileName; }V93~>  
} f@,hO5h(_|  
2- |
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public void setSFileName(String value) U?+30{hb  
{ s%0[
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sFileName = value; ;dpS@;v  
} f%(e,KgW=  
SWe!9Y$  
:&\E\9  
public int getNSplitter() $bM#\2'  
{ ijR*5#5h  
return nSplitter; "pKGUM  
} b(.o|d/P  
0B!mEg  
*N&^bF"SF  
public void setNSplitter(int nCount) 5y 'ycTjY  
{ ~O7cUsAi'  
nSplitter = nCount; ?!Th-Cc&m  
} y:(C=*^<t  
} [{d[f|  
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SgQmYaa&  
/* SE7 (+r  
**Utility.java Ltq*Vcl\  
*/ |Jx2"0:M  
package NetFox; l1.Aw|'D  
30T:* I|  
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public class Utility {
q;He:vX  
WZy6K(18"'  
e]L3=R;  
public Utility() u/c~PxC  
{ y<gYf -E+  
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} 4s+J-l  
?28G6T]/?d  
//线程睡眠  TVEF+t  
public static void sleep(int nSecond) 2>_LX!kyP]  
{ Ee?K|_\${  
try{ 'E6gEJ  
Thread.sleep(nSecond); Am}PXj6  
} 7n3x19T  
catch(Exception e) oXZ@*   
{ &rtz&}Z
B;  
e.printStackTrace (); H1c|b!C  
} aDJjVD  
} WFc[F`b  
'\vmfp=  
//日志 eVNBhR}HS  
public static void log(String sMsg) t1_y1!uQ  
{ =dw*B
 
System.err.println(sMsg); nr9#3Lb  
} B0?@k  
= ,E(!Sp  
$hY]EB  
public static void log(int sMsg) eNk!pI7g  
{ `[HoxCV3o  
System.err.println(sMsg); ]NhWhJ:  
} n;
T  
} )T~ +>+t  
Y_iF$m/R  
)<&CnK  
/* A.cZa  
**TestMethod.java z_iyuLRdb  
*/ :^.87>V7  
package NetFox; j$i8@]  
^Y*.Ktp,o  
'MM~~:  
public class TestMethod { q,h.W JI  
IfI$  
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public TestMethod() Svp
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{ ///xx/weblogic60b2_win.exe [Kj#KJxy  
try{ F v^80M=z  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Sy7^;/(ZZ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); |Btx&'m  
SiteFileFetch fileFetch = new SiteFileFetch(bean); /r 2.j3:l  
fileFetch.start(); U~`^Y8UF  
} /01(9(  
catch(Exception e){e.printStackTrace ();} (DaP~*c3cC  
-t
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)( jNd&H  
} l4.@YYzbp.  
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(Y@|h%1W  
public static void main(String[] args) we).8%)'  
{ 2o7C2)YT$  
new TestMethod(); N`GwL aF  
} &=t(N
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} -VT?/=Y s  
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