http断点续传简单实现（java)

/* Dw6mSsC/  
**SiteFileFetch.java  N\9Wxz$  
*/ j6_
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package NetFox; =xq+r]g6  
import java.io.*; aEW sru  
import java.net.*; 5p7?e3  
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public class SiteFileFetch extends Thread { e7^B3FOx  

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SiteInfoBean siteInfoBean = null; //文件信息Bean ^E^Cj;od@  
long[] nStartPos; //开始位置 - .EH?{i  
long[] nEndPos; //结束位置 .sOEqwO}>  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?]]d 
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long nFileLength; //文件长度 2)zAX"#
/  
boolean bFirst = true; //是否第一次取文件 C>:'@o Z  
boolean bStop = false; //停止标志 b,Vg3BS  
File tmpFile; //文件下载的临时信息 3</gK$f2  
DataOutputStream output; //输出到文件的输出流 H${5pY_M  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Z>si%Npm\  
public SiteFileFetch(SiteInfoBean bean) throws IOException O<o>/HH$  
{ ~d072qUos  
siteInfoBean = bean; M)JKe!0ad1  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Dxlpo! ?#  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); p2/Pj)2  
if(tmpFile.exists ()) T7bDt  
{ WQ1~9#  
bFirst = false; muJR~
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read_nPos(); 88l\8k4r  
} RMvq\J}w!  
else 9cwy;au  
{ Z=&cBv4Fs  
nStartPos = new long[bean.getNSplitter()]; f6r~Ycf,f  
nEndPos = new long[bean.getNSplitter()]; $ rU"Krf67  
}
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} ^I CSs]}1  
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public void run() !
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{ f"}g5eg+  
//获得文件长度 ac%6eW0#  
//分割文件 7B)m/%>3s  
//实例FileSplitterFetch 1z5Oi u  
//启动FileSplitterFetch线程 ;#Y'SK  
//等待子线程返回 qLYz-P'ik  
try{
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if(bFirst) D,l&^diz  
{ QK`5KB(k'  
nFileLength = getFileSize(); nR(v~_y[V  
if(nFileLength == -1) EIrAq!CA  
{ ~Bi>T15e  
System.err.println("File Length is not known!"); S[ln||{  
}
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else if(nFileLength == -2) 'OTQiI^t=  
{ * ",/7(  
System.err.println("File is not access!"); fR$_=WWN>h  
} ' %&gER  
else js..k
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{ . \t8s0A  
for(int i=0;i<nStartPos.length;i++) rn9n_)  
{ Oe~x,=X)  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9>6DA^
 
} rV_i|  
for(int i=0;i<nEndPos.length-1;i++) @$aGVEcU$  
{ / :z<+SCh  
nEndPos = nStartPos[i+1]; x=M%QFe  
} sW^e D;  
nEndPos[nEndPos.length-1] = nFileLength; /2.}m`5  
} K8bKTG\  
} =f/CBYNw@V  
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//启动子线程 S T1V  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; QHDR*tB:{  
for(int i=0;i<nStartPos.length;i++) ]T:a&DHC  
{ b$;qtfJG  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _@5|r|P>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), vk0b b3){D  
nStartPos,nEndPos,i); |ns B'Q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,` 64t'g  
fileSplitterFetch.start(); T@%\?=P  
} B%^W$7 q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bt{b%r  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Ls`[7w  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0H/)wy2ym  
nEndPos = " + nFileLength); d@XXqCR<  
// fileSplitterFetch[nPos.length-1].start(); JyO2P  
)UCc!  
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//等待子线程结束 cE;n>ta"F  
//int count = 0; bQ3txuha  
//是否结束while循环 (yb$h0HN  
boolean breakWhile = false; l@)`Q  
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while(!bStop) lz7?Z  
{ }6_*i!68"U  
write_nPos(); Lc#GBaJ  
Utility.sleep(500); 2{Y~jYt{h  
breakWhile = true; z?^oy.  
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for(int i=0;i<nStartPos.length;i++) p9>1a j2a  
{ `y|_hb  
if(!fileSplitterFetch.bDownOver) Uv m:`e~?  
{ ZXIw^!8@/  
breakWhile = false; oo\7\b#Jx  
break; @V&c=8)8  
} g\% Z+Dc  
} AU
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if(breakWhile) E|vXM"zFl  
break; [=BccT:b  
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//count++; ;_=N YG.  
//if(count>4) PU,%Y_xR  
// siteStop(); UCt}\IJ  
} a$j ~YUG_  
)qRH?Hsb7  
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System.err.println("文件下载结束！"); %s! |,Cu  
} H76iBJ66  
catch(Exception e){e.printStackTrace ();} s IFE:/1,  
} g<N;31:c\  
^)(-7H  
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//获得文件长度 bksv2@ar  
public long getFileSize() ?I[*{}@n"  
{ : eCeJ~&E  
int nFileLength = -1; Sv_Nb>  
try{ 0|Xz-Y  
URL url = new URL(siteInfoBean.getSSiteURL()); N=PSr4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); EE^x34&=  
httpConnection.setRequestProperty("User-Agent","NetFox"); kuI~lBWI  
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int responseCode=httpConnection.getResponseCode(); >J5C.hx  
if(responseCode>=400) T]JmnCX>:  
{ q;}iW:r&Q  
processErrorCode(responseCode); \_ V*Cs  
return -2; //-2 represent access is error _u+ 7>  
} Mj{w/'  
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r'`7}@H*  
String sHeader; M
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for(int i=1;;i++) ^v`naA(  
{ ftG3!}  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); o]Xt2E  
//Utility.log(in.readLine()); 41x"Q?.bY  
sHeader=httpConnection.getHeaderFieldKey(i); /O5&)%N  
if(sHeader!=null) eP,bFc  
{ QtwQVOK  
if(sHeader.equals("Content-Length"))
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{ .faf!3d  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Y hQ)M5  
break; N
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} 8
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}  vTgx7gP  
else x_/}R3d  
break; n1JtY75#,/  
} tYXE$i  
} {l)$9!  
catch(IOException e){e.printStackTrace ();} EJ>&\Iq  
catch(Exception e){e.printStackTrace ();} fZezDm(Q  
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Utility.log(nFileLength); o K>(yC[  
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return nFileLength; ,sIC=V +  
} @AF<Xp{  
V^,eW!  
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//保存下载信息（文件指针位置） \"1>NJn&k)  
private void write_nPos() Z6rhInIY  
{ MoE&)~0u&  
try{ (c>g7d<>n  
output = new DataOutputStream(new FileOutputStream(tmpFile)); l2LLM
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output.writeInt(nStartPos.length); p]%di8&;N  
for(int i=0;i<nStartPos.length;i++) =C2sl;7~*  
{ [lg!*  
// output.writeLong(nPos); vjq2(I)u  
output.writeLong(fileSplitterFetch.nStartPos); )Xh}N  
output.writeLong(fileSplitterFetch.nEndPos); o]~\u{o#.  
} d)emTXB(  
output.close(); `0N7Gc  
} J Cq>;br.  
catch(IOException e){e.printStackTrace ();} <(q(5jG  
catch(Exception e){e.printStackTrace ();}  ]'`E  
} m/1FVC@*  
b?l>vUgAg  
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//读取保存的下载信息（文件指针位置） 0muC4  
private void read_nPos() B ytx.[zbX  
{ t&xoi7!$  
try{ 8 ECX[fw  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); X3\PVsH$K  
int nCount = input.readInt(); !+Xul_XG  
nStartPos = new long[nCount]; cf88Fd6l/  
nEndPos = new long[nCount]; Oj;*Gi9E  
for(int i=0;i<nStartPos.length;i++) H; NV?CD  
{ FDQ=$w}'>  
nStartPos = input.readLong(); U\p`YZ  
nEndPos = input.readLong(); a(|6)w-  
} %(1OjfZc  
input.close(); ~<?Zj  
} TIKkS*$  
catch(IOException e){e.printStackTrace ();} *3H=t$1G}  
catch(Exception e){e.printStackTrace ();} _Xt/U>N  
} 16zReI(  
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private void processErrorCode(int nErrorCode) 9F>`M  
{ >[AmIYg  
System.err.println("Error Code : " + nErrorCode); "_q~S$i
^  
} SvT0%2  
1o`1W4Q  
E ?Mgbd3  
//停止文件下载 rXi&8R[  
public void siteStop() [zx|3wWAX-  
{ l S)^8  
bStop = true; {+WBi(=W  
for(int i=0;i<nStartPos.length;i++) w6i2>nu_O  
fileSplitterFetch.splitterStop(); ryVYY>*(K  
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} |Dn Zk3M,  
} ZC N}iQu4  
//负责部分文件的抓取 [(heE  
**FileSplitterFetch.java DjM*U52Yfj  
*/ sfyLG3$/  
package NetFox; LN|(Z*  
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import java.io.*; w'K7$F51  
import java.net.*; CefFUqo4  
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public class FileSplitterFetch extends Thread { (oGYnN,2  
}PBme'kP  
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String sURL; //File URL c!ZZMCs  
long nStartPos; //File Snippet Start Position k( :Bl  
long nEndPos; //File Snippet End Position 6G2~'zqPc~  
int nThreadID; //Thread's ID <D/K[mz-  
boolean bDownOver = false; //Downing is over >qo!#vJc a  
boolean bStop = false; //Stop identical ?6CLUu|7n  
FileAccessI fileAccessI = null; //File Access interface R iLl\S#  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException N4vcd=uG#  
{ EB}B75)x  
this.sURL = sURL; a;xeHbE
 
this.nStartPos = nStart; SZF 8InyF  
this.nEndPos = nEnd; ^2~ZOP$A  
nThreadID = id; Kk8wlC  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8"j$=T6;W  
} c["1t1G  
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public void run() },8|9z#pyB  
{ NftnbsTmy  
while(nStartPos < nEndPos && !bStop) "z{/*uM2<  
{ @P7'MiP]K  
/x??J4r0  
I _KHQ&Z*  
try{ FBXktSg  
URL url = new URL(sURL); )/jDt dI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); gy}3ZA*F  
httpConnection.setRequestProperty("User-Agent","NetFox"); cy8>M))c  
String sProperty = "bytes="+nStartPos+"-"; 8J3#(aBm  
httpConnection.setRequestProperty("RANGE",sProperty); "du(BZw  
Utility.log(sProperty); m^QoB  
^*}D*=>\  
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InputStream input = httpConnection.getInputStream(); 28"1ONs3  
//logResponseHead(httpConnection); VZi1b0k1.  
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byte[] b = new byte[1024]; G3_7e A#;  
int nRead; =`3r'c  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) l ms^|?  
{ i{fw?))+  
nStartPos += fileAccessI.write(b,0,nRead); sWlxt qg  
//if(nThreadID == 1) )Z:-qH  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T \/^4N`  
} nX!%9x$3  
hl:Ba2_E +  
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Utility.log("Thread " + nThreadID + " is over!"); !V.]mI  
bDownOver = true; ~EBaVl ({  
//nPos = fileAccessI.write (b,0,nRead); 2H`r:x<Z-  
} (2;Aqx5i  
catch(Exception e){e.printStackTrace ();} mfj{_fR3  
} E!Q@AZ  
} i3)3.WK^  
]V/5<O1  
q]="ek&_  
//打印回应的头信息 E:9RskI  
public void logResponseHead(HttpURLConnection con) &}u_e`A  
{ w: BJ4bi=  
for(int i=1;;i++) ._0$#J S[  
{ 5S4Nx>  
String header=con.getHeaderFieldKey(i); X?haHM#]  
if(header!=null) /RB%m8@;  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %`bs<ZWT  
Utility.log(header+" : "+con.getHeaderField(header)); %Ik5|\ob?  
else JYc:@\   
break; s]m]b#1!r  
} %72# tY  
} 
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public void splitterStop() ~~{lIO)&  
{ |KJGM1]G  
bStop = true; r3Ol?p  
} YHN6/k7H  
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oT}$N_gFT  
} d[h=<?E5  
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/* q}_8iDO6  
**FileAccess.java #sU>L=  
*//文件访问(定位，写) k x:+mF  
package NetFox; 8;qOsV)UDT  
import java.io.*; mg*iW55g  
!"hlG^*9  
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public class FileAccessI implements Serializable{ LiEEQ  
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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 Nn_b  
RandomAccessFile oSavedFile; t]sk[  
long nPos; @^0}wk  
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public FileAccessI() throws IOException \/dOv

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{ jXx~5  
this("",0); /\fR6|tJ  
} sB0]lj-[Un  
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public FileAccessI(String sName,long nPos) throws IOException ]#N8e?b,  
{ ;-i)}<  
oSavedFile = new RandomAccessFile(sName,"rw"); vo#$xwm1  
this.nPos = nPos; \ $TM=Ykj  
oSavedFile.seek(nPos); T pCXe\W  
} un\o&0}  
^d>m`*px  
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public synchronized int write(byte[] b,int nStart,int nLen) qW3XA$g|j'  
{ +^J&x>5  
int n = -1; `_DA!  
try{ \HD:#a  
oSavedFile.write(b,nStart,nLen); Uv
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n = nLen; "wVisL2+.  
} )[99SM   
catch(IOException e) 2L<1]:I  
{ F
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e.printStackTrace (); ZHRMW'Ne  
} 3Q&@l49q  
z>W?\[E<2  
#H
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return n; f/ 3'lPK^  
} .mnkV -m  
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} e9\_H=t+  
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/* 4{,!'NA  
**SiteInfoBean.java 0 Swu]OE  
*/ >xRUw5jN  
package NetFox; HII@Ed f?  
uEsF 8  
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public class SiteInfoBean { 4tkb7D q  
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private String sSiteURL; //Site's URL R<3 -!p1v  
private String sFilePath; //Saved File's Path iQ;lvOja  
private String sFileName; //Saved File's Name Ut%{pc 7^F  
private int nSplitter; //Count of Splited Downloading File %f\j)qw  
^Ux.s Q  
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public SiteInfoBean() "6~+-_:  
{//nSplitter的缺省值为5 A{3nz DLI  
//default value of nSplitter is 5 ]:#W$9,WL  
this("","","",5); h1Y^+A_  
} ?J|
 
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p=[I;U-#H  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Eb'M< ZY  
{ t@2MEo  
sSiteURL= sURL; 5H
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sFilePath = sPath; 5rtE/{A  
sFileName = sName; PTQN.[bBh  
this.nSplitter = nSpiltter; =OrVaZ0  

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} Q*f0YjH!  
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public String getSSiteURL() ZlMS=<hgFx  
{ 6m:$RW  
return sSiteURL; p`"Ic2xPJ  
} on7?V<  
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public void setSSiteURL(String value) ;Rxc(tR!n  
{ aMK\&yZD  
sSiteURL = value; z2A,*|I  
} dM -<aq  
{H=<5  
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public String getSFilePath() 1O2V!?P  
{ *mw *z|-^V  
return sFilePath; M^n^wz  
} X4k|k>  
+wGvYr  
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public void setSFilePath(String value) n&Q0V.  
{ DRVvC~M-,  
sFilePath = value; n482?Wp  
} Nc^:v/(P  
7 $dibTER  
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public String getSFileName() T#}"?A|  
{ GG4FS  
return sFileName; Jg&f.  
} U*BI/wZ  
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public void setSFileName(String value) usU6,  
{ %mS>v|  
sFileName = value; iML?`%/vN  
} MMQ\V(C  
0Y!~xyg/  
I#(?xHx  
public int getNSplitter() EQy~ ^7V B  
{ c&g*nDuDj  
return nSplitter; 0.~s>xXp  
} XS>( Bu  
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public void setNSplitter(int nCount) .
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{ [KEw5-=i@  
nSplitter = nCount; ;IT'6m`@W  
} :?gp}.  
} t&o&gb  
%y+v0.aWH+  
bc6|]kB:  
/* &'m&'wDt:  
**Utility.java +[V.yY/t|>  
*/ 
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package NetFox; 
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public class Utility { cOdgBi  
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public Utility() .aC/ g?U  
{ 7Y 4!  
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} F ^)( 7}ph  
-{p~sRc&  
//线程睡眠 cZ,}1?!  
public static void sleep(int nSecond) Cv< s|  
{ ^= qL[S6/M  
try{ eB<R"Yvi  
Thread.sleep(nSecond); ?V =#x.9  
} we33GMxHl`  
catch(Exception e) u"U7aYGkY  
{ cE*d(g  
e.printStackTrace (); 'Z6x\p  
} gAK"ShOhG=  
} v+DXs!O{  
NqN}] nu6  
//日志 gq.l=xS  
public static void log(String sMsg) WS\Ir-B  
{ S3y(' PeF  
System.err.println(sMsg); o}Q3mCB  
} *dxE (dP  
l-8rCaq&J  
pE{Ecrc3|  
public static void log(int sMsg) B#o6UO\  
{ R-Gg= l5  
System.err.println(sMsg); :;w#l"e7<  
} =DXN`]uN  
} 4 udW6U  
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4V'HPD>=V  
/* be HEAQ  
**TestMethod.java E_#?;l>  
*/ rs0Wy  
package NetFox; lB   
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public class TestMethod { AK&=/[U>  
6P02=  
-o@L"C>  
public TestMethod() CrYPcvd6  
{ ///xx/weblogic60b2_win.exe ?DKY;:dZF  
try{  ^]?juL  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2k^'}7G%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); |Zdl[|kX  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }qBmt>#  
fileFetch.start(); 5I/lFoy7  
} yVyh\u\  
catch(Exception e){e.printStackTrace ();} pL
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} [=^Wj`;  
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public static void main(String[] args) _>4)q=  
{ U,Fyi6{~  
new TestMethod(); ^`bMFsP  
} pz]!T'  
} EvF[h:C2  
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