http断点续传简单实现（java)

/* Kzz]ZO*3  
**SiteFileFetch.java N)N\iad^  
*/ ";$rcg"%X  
package NetFox; qZ|>{^a*  
import java.io.*; @ob4y  
import java.net.*; (zL(  
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tNbZ{=I>  
public class SiteFileFetch extends Thread { f hS4Gb_  
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SiteInfoBean siteInfoBean = null; //文件信息Bean K|g+Wt^tQ  
long[] nStartPos; //开始位置 fkmN?CU{1%  
long[] nEndPos; //结束位置 5$.e5y<&(  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 i$:QOMA  
long nFileLength; //文件长度 M h5>@-fEE  
boolean bFirst = true; //是否第一次取文件 A9L {c!|-  
boolean bStop = false; //停止标志 ofIw7D*h  
File tmpFile; //文件下载的临时信息 RNB ha&  
DataOutputStream output; //输出到文件的输出流 jizp\%W+  
}Uc)i
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） >p|tIST  
public SiteFileFetch(SiteInfoBean bean) throws IOException eod-N}o  
{ % A8dO+W  
siteInfoBean = bean; /3ty*LQT  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }4A $j{\  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); pwG"_|h  
if(tmpFile.exists ()) d2XSw>  
{ ,U^V]
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bFirst = false; 2J5RZg9jL  
read_nPos(); m0zbG1OE  
} `rLy7\@;  
else -U#e  
{ 1L\\](^ 3  
nStartPos = new long[bean.getNSplitter()]; #2\ 0#H
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nEndPos = new long[bean.getNSplitter()]; xpjv@P  
} Q5~Y;0'  
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} zEYT,l  
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public void run() r[}5<S Q  
{ ,8^QV3  
//获得文件长度 /$NZj"#  
//分割文件 o+j~~P  
//实例FileSplitterFetch qe{:9  
//启动FileSplitterFetch线程 |}Wm,J  
//等待子线程返回 ./#F,^F2  
try{ "g=g' W#  
if(bFirst) s}5,<|DL  
{ e0; KmQjG  
nFileLength = getFileSize(); SZ'2/#R>  
if(nFileLength == -1) WQ>y;fi5/{  
{ y>YQx\mK
 
System.err.println("File Length is not known!"); XzF-g*e  
} yRF %SWO  
else if(nFileLength == -2) {InD/l'v6n  
{ ?@uyqi~:U  
System.err.println("File is not access!"); C0> Z<z  
} 'l7ey3B%  
else 4gkaCk{]  
{ U.,_zEbx,  
for(int i=0;i<nStartPos.length;i++) 6< T@\E  
{ y/(60H,{{  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ;VI/iwg  
} mufJ@YS#  
for(int i=0;i<nEndPos.length-1;i++) 7j22KQ|EX^  
{ gfY1:0  
nEndPos = nStartPos[i+1]; (m3 <)  
} PZjK6]N\  
nEndPos[nEndPos.length-1] = nFileLength; `1fNB1c  
} 9nrmz>es|-  
} td"D&1eQ@  
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//启动子线程 +8#hi5e  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; zOfMKrRG  
for(int i=0;i<nStartPos.length;i++) aHR&6
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{ rOyKugHe  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T}55ZpSC&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), h.%)RW?  
nStartPos,nEndPos,i); ^^FqN;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I"5VkeIx  
fileSplitterFetch.start();
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%\#rw  
} 6hX[5?}  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 2QN ~E  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", nQ5N\RAZ  
nEndPos = " + nFileLength); c ?(X(FQ  
// fileSplitterFetch[nPos.length-1].start(); 2iV/?.<Z&  
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o NqIrYH'  
//等待子线程结束 h:3^FV&#  
//int count = 0; :)eU)r"s4  
//是否结束while循环 ]aN]Ha  
boolean breakWhile = false; ~(~ y=M  
 q0y#Y  
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while(!bStop) KW 78J~u+  
{ u4
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write_nPos(); s-"oT=  
Utility.sleep(500); (l]_0-Z  
breakWhile = true; |[B JZ  
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for(int i=0;i<nStartPos.length;i++) ];63QJU  
{ 'n dX
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if(!fileSplitterFetch.bDownOver) ~M?^T$5  
{ QGoBugU  
breakWhile = false; .2v)x  
break; VTIRkC wl@  
} GJo`9  
} oT}-i [=}  
if(breakWhile) :% m56  
break; }xG~a=,  
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//count++; 'irHpN6n  
//if(count>4) nKu)j3o`  
// siteStop(); nSR<(-j!  
} I/`\>Hk  
*ud/'HR8]  
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System.err.println("文件下载结束！"); RJ0:O  
} f~-qjEWm  
catch(Exception e){e.printStackTrace ();} .;,` bH0  
} 2Cgq&\wS  
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3@8Zy:[8<  
//获得文件长度 kl[Jt)"4@  
public long getFileSize() oa q!<lI  
{ 4E0 Y=  
int nFileLength = -1; l37) Q  
try{ RJa1pYK  
URL url = new URL(siteInfoBean.getSSiteURL()); u|EHe"V"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vL ]z3  
httpConnection.setRequestProperty("User-Agent","NetFox"); e4<[|B!O  
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int responseCode=httpConnection.getResponseCode(); qtYVX:M@,  
if(responseCode>=400) h'|J$  
{ =OR"Bd:O  
processErrorCode(responseCode); cOrFe;8-.  
return -2; //-2 represent access is error m&{%6  
} A=bBI>GEYP  
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String sHeader; kB3@;z:  
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for(int i=1;;i++) M'>8P6O  
{ 7rSads  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 6~.{~+Bd  
//Utility.log(in.readLine()); S*w;$`Y  
sHeader=httpConnection.getHeaderFieldKey(i); >4iVVs  
if(sHeader!=null) 9~ rYLR(v  
{ JK9 J;c#T  
if(sHeader.equals("Content-Length")) GS&iSjw  
{ ,cCBAOueO  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )FSa]1t;x  
break; DC+l3N  
} c6~<vV'}  
} 1Q6~O2a  
else R!y`p:O C  
break; ka?EXF:  
} KbM1b  
} o|bm=&f  
catch(IOException e){e.printStackTrace ();} FQqk+P!  
catch(Exception e){e.printStackTrace ();} /j$`Cq3I  
'd |*n#Dqc  
}+dDGFk  
Utility.log(nFileLength); *9)yN[w  
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07#e{   
return nFileLength; r";;Fk#5  
} y|2y!&o,!  
!63]t?QXMG  
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//保存下载信息（文件指针位置） ?CSv
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private void write_nPos() cu )w6!f  
{ wq =Ef  
try{ .ovG_O  
output = new DataOutputStream(new FileOutputStream(tmpFile)); "?r_A*U  
output.writeInt(nStartPos.length); >&D}^TMYY  
for(int i=0;i<nStartPos.length;i++) Xcw6mpLt  
{ V8-*dE  
// output.writeLong(nPos); Q~zs]{\  
output.writeLong(fileSplitterFetch.nStartPos); `FHKQS5  
output.writeLong(fileSplitterFetch.nEndPos); t*(buAx  
} aM!%EaT  
output.close(); "U o~fJ  
} BVe c  
catch(IOException e){e.printStackTrace ();} Y"UB\_=  
catch(Exception e){e.printStackTrace ();} u=f}t=3  
} K(75)/  
|$G|M=*LN  
}[b3$WZ  
//读取保存的下载信息（文件指针位置） D0VbD" y  
private void read_nPos() A40Q~X  
{ [Nv)37|W  
try{ H*E4+3y  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); kJk6lPSqi7  
int nCount = input.readInt(); b<8,'QgB  
nStartPos = new long[nCount]; "pTU&He  
nEndPos = new long[nCount]; zY2o;-d|4  
for(int i=0;i<nStartPos.length;i++) cg).b?g  
{ ?AYb@&%  
nStartPos = input.readLong(); B'8T+qvA  
nEndPos = input.readLong(); |DkK7gw  
} M&J$9X  
input.close(); I08W I u  
} u`Abko<D  
catch(IOException e){e.printStackTrace ();} ':#DROe!  
catch(Exception e){e.printStackTrace ();} :)DvZxHE@  
} ^ RIWW0  
S:{`eDk\A_  
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private void processErrorCode(int nErrorCode) >bbvQb+j  
{ iCNJ%AZH  
System.err.println("Error Code : " + nErrorCode); I~)A!vp  
} n#"N"6s  
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//停止文件下载 e_3($pj  
public void siteStop() 5KC Zg'h  
{ l dw!G/  
bStop = true; W,bu=2K6  
for(int i=0;i<nStartPos.length;i++) $*c!9Etl4  
fileSplitterFetch.splitterStop(); @BoZZ  
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} Kdr}7#c  
} {VT**o  
//负责部分文件的抓取 M@<r8M]G  
**FileSplitterFetch.java a,eJO??  
*/ NN]
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package NetFox; O6$n VpD3  
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import java.io.*; 8T}Dn\f  
import java.net.*; +Y"HbNz
 
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public class FileSplitterFetch extends Thread { Rgb&EnVW  
=i:,")W7=  
{+jO/ZQu5  
String sURL; //File URL Q3rLCg,;  
long nStartPos; //File Snippet Start Position }.N~jx0R  
long nEndPos; //File Snippet End Position c_Jcy  
int nThreadID; //Thread's ID 1{.5X8y1x  
boolean bDownOver = false; //Downing is over i#:M2&twE  
boolean bStop = false; //Stop identical <|1Khygv  
FileAccessI fileAccessI = null; //File Access interface L|Bjw3K&D  
w-P;E!gTt  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException EqF>=5*  
{ h.4FY<  
this.sURL = sURL; `i)Pf WdBN  
this.nStartPos = nStart; >6Ody<JPHP  
this.nEndPos = nEnd; q_z;kCHM  
nThreadID = id; (CrP6]=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 BY>]6SrP  
} hUe\sv!x?  
;!,I1{`  
vY);7  
public void run() pMV?vH  
{ *X8Pa;x  
while(nStartPos < nEndPos && !bStop) EL(BXJrx{  
{ !112u#V  
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try{ a^7QHYJ6  
URL url = new URL(sURL); b]g
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ccwz:7r  
httpConnection.setRequestProperty("User-Agent","NetFox"); g4&f2D5  
String sProperty = "bytes="+nStartPos+"-"; FXh*!%"*  
httpConnection.setRequestProperty("RANGE",sProperty); SS!b`  
Utility.log(sProperty); iM M s3  
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InputStream input = httpConnection.getInputStream(); Qb8Z+7  
//logResponseHead(httpConnection); 2[i(XG{/  
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byte[] b = new byte[1024]; ?^WX]SAl  
int nRead; 5V8`-yO9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) S~U5xM^s  
{ OlX#1W]  
nStartPos += fileAccessI.write(b,0,nRead);  T
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//if(nThreadID == 1) e, }{$HStZ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d#|%h] 6  
} G6pR?K+  
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Utility.log("Thread " + nThreadID + " is over!"); X3HJ3F;==  
bDownOver = true; %J+k.UrM  
//nPos = fileAccessI.write (b,0,nRead); 8^!ib/@v"  
} 1pP q)}=+  
catch(Exception e){e.printStackTrace ();} !*PX
-  
} N5mhs#  
} >OKc\m2%Q  
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@  
//打印回应的头信息 85BB{T;  
public void logResponseHead(HttpURLConnection con) }c=YiH,o  
{ EpK7VW  
for(int i=1;;i++) m O"Rq5  
{ =yZ6$ hK  
String header=con.getHeaderFieldKey(i); y=zs6
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if(header!=null) "qoJIwl#q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <`Qbb=*  
Utility.log(header+" : "+con.getHeaderField(header)); aB{OXU}#  
else 3j2d&*0  
break;
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} R'qBG(?i  
} Y8for'  
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public void splitterStop() Se|h]+G  
{ |8fdhqy_  
bStop = true; HG^
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} LBIEG_/m  
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} Tsocc5gWZ*  
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7%W@Hr,%F  
/* ihD|e&  
**FileAccess.java '![VA8  
*//文件访问(定位，写) G0(A~Q"  
package NetFox; e}ivvs2  
import java.io.*; $]MOAj"LH  
U04)XfO;]  
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public class FileAccessI implements Serializable{ \~.elKw<U  
n<Ki.;-ZE  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 rB_ESNx  
RandomAccessFile oSavedFile; Mo\nY5  
long nPos; ([]\7}+8  
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public FileAccessI() throws IOException E//*bmww  
{ 6>b'g ~I  
this("",0); +1Pu29B0  
} G$s=P  
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public FileAccessI(String sName,long nPos) throws IOException lM.k*`$  
{ Kir|in)r0  
oSavedFile = new RandomAccessFile(sName,"rw"); :@S=0|:j  
this.nPos = nPos; 02C;  
oSavedFile.seek(nPos); OT#foP  
} aZ}z/.b]  
(, $Lp0mB7  
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public synchronized int write(byte[] b,int nStart,int nLen) BR
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{ xLw[ aYy4  
int n = -1; eNrwkV^  
try{ rLcXo%w  
oSavedFile.write(b,nStart,nLen); ZWx4/G  
n = nLen; @}{Fw;,(7n  
} ._<gc;G  
catch(IOException e) 9mEhZ"  
{ %3T:W\h  
e.printStackTrace (); c3Zwp%  
} i|fkwV,5  
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return n; C3b<Wa])  
} 29NP!W /g  

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} MJ.Kor  
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/* m^4Ojik  
**SiteInfoBean.java 3Z74&a$  
*/ ]o
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package NetFox; q[+V6n`Z5  
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public class SiteInfoBean { [Rzn>  
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private String sSiteURL; //Site's URL ?{>5IjL)en  
private String sFilePath; //Saved File's Path \?AA:U*  
private String sFileName; //Saved File's Name kaVYe)~  
private int nSplitter; //Count of Splited Downloading File v[>8<z8  

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public SiteInfoBean() >Yfo $S_  
{//nSplitter的缺省值为5 [bd?$qi  
//default value of nSplitter is 5 b<KKF'  
this("","","",5); osTin*T.  
} PAu/iqCH  
#b{;)C fL  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) g'V,K\TG  
{ / !A&z4;D  
sSiteURL= sURL; ^7C,GaDsn  
sFilePath = sPath; h3;RVtS  
sFileName = sName; Wl3fR[@3Q  
this.nSplitter = nSpiltter; ;T WYO  
1JN/oq;  
k)JwCt.%  
} #K/#-S  
Y'o.`':\~  
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public String getSSiteURL() hj[sxC>z5  
{ 6dYUMqQ  
return sSiteURL; @m"P_1`*  
} r5&?-G  
="]y^&(L(  
Fi"TY^-E;  
public void setSSiteURL(String value)
.vXe}%  
{ IF|%.%I$!U  
sSiteURL = value; x[2eA!NC  
} S]biN]+7s  
9|//_4]  
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public String getSFilePath() uB35CRd  
{ i%9xt1c_  
return sFilePath; /f -\ 3  
} BU;E6s>P  
) 2Hl\"F  
+K[H!fD  
public void setSFilePath(String value) P4~C0z  
{ N9cUlrD
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sFilePath = value; ^v@& q  
} 1PT0<C-  
kam\
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public String getSFileName() a5%IjgQ&z  
{ y?{YQ)fj  
return sFileName; PWs=0.Wj  
} 5[$jrG\!  
>]WQ1E[=  
z=VL|Du1OT  
public void setSFileName(String value) h:'wtn@l(  
{ o^~KAB7  
sFileName = value; Le}-F{~`^  
} X3rvM8  
O.+X,CQG*  
04R-}  
public int getNSplitter() C?%Oi:Gi&  
{ 1fb!sbGD.k  
return nSplitter; ,]-A
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} {siIRl2&  
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*7 >K"j  
public void setNSplitter(int nCount) -AU!c^-o  
{ 9~WjCa*,&  
nSplitter = nCount; +W9#^  
} L\X2Olfz1  
} -m>ng E~q  
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/* Po8
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**Utility.java .(2ui~ed  
*/ $qj||zA  
package NetFox; Md,KW#  
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 (.B+U'6  
public class Utility { ?]u=5gqUU  
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public Utility() ~b.e9FhdA  
{ S4BU!  
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%QrpFE5V5  
} au 5qbP  
;p'Ej'E  
//线程睡眠 xBi``x2eY  
public static void sleep(int nSecond) ]pP [0S  
{ 9~$'?  
try{ Gfn?1Kt{  
Thread.sleep(nSecond); ?_7^MP>  
} z gDc=  
catch(Exception e) seo.1.Da2  
{ }~`l!ApD  
e.printStackTrace (); j-j,0!T~b  
} )X-/0G=N-  
}
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'VTLp.~G~  
//日志 rfS kQT  
public static void log(String sMsg) &%4*~;o  
{ (Cjw^P|Y@  
System.err.println(sMsg); _l;$<]re\k  
} E<XrXxS1O  
g}=opw
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<rpXhcR  
public static void log(int sMsg) \zPcnDB  
{ )~l`%+
 
System.err.println(sMsg); @-QDp`QtI  
} ,a/<t"  
} Cn>RUGoUsI  
D#G(&<Q  
c/G]r|k  
/* Y^@Nvt$<K  
**TestMethod.java R3=]Av46  
*/ Fxr$j\bm  
package NetFox; D27MT/=7  
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i+HHOT  
public class TestMethod { x<%V&<z1g  
Lk~aMbw#  
J_PbRb  
public TestMethod() =^LX,!2zp{  
{ ///xx/weblogic60b2_win.exe $pg1Av7l  
try{ yl[6b1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `<:D.9vO "  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); A(Ss:7({  
SiteFileFetch fileFetch = new SiteFileFetch(bean); _7LZ\V+MLW  
fileFetch.start(); 1Xi.OGl  
} zn@yt%PCV  
catch(Exception e){e.printStackTrace ();} +(|6Wv  
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cc^[u+  
} y=)xo7(  
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b];p/V# <  
public static void main(String[] args) $M=W`E[g  
{ {)8!>K%G  
new TestMethod(); ]FLi^}ct  
} CUR70[pB)  
} (n,!
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