http断点续传简单实现（java)

/* :d9GkC  
**SiteFileFetch.java K<:%ofB"S  
*/ {q`8+$Z;  
package NetFox; >n3GvZ5%  
import java.io.*; fo+s+Q|Y  
import java.net.*; Y @'do)  
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public class SiteFileFetch extends Thread { \t1#5  
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SiteInfoBean siteInfoBean = null; //文件信息Bean q[VQ?b~9  
long[] nStartPos; //开始位置 l"E{ ?4  
long[] nEndPos; //结束位置 }dzVwP=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 p?>J86%[  
long nFileLength; //文件长度 $3l#eKZA  
boolean bFirst = true; //是否第一次取文件 .z_nW1id  
boolean bStop = false; //停止标志 {Kr}RR*{X  
File tmpFile; //文件下载的临时信息 ~`&4?c3p  
DataOutputStream output; //输出到文件的输出流 BHAFO E  
*X$qgSW  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） >QvqH 2  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1Z)P.9c  
{ hWbu

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siteInfoBean = bean; #*.4Jv<R  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); y\;oZ]J  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^i#0aq2}  
if(tmpFile.exists ()) #*qV kPX  
{ _g/d/{-{Q  
bFirst = false; >*gf
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read_nPos(); SF*mY=1  
} KTT
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else BM:p)%Pv#P  
{ d*Su c  
nStartPos = new long[bean.getNSplitter()]; /nA>ox78  
nEndPos = new long[bean.getNSplitter()]; F/lL1nTdK  
} CHv n8tk  
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} Bf00&PE;  
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public void run() ";(m,if-  
{ qXq#A&  
//获得文件长度 nbP}a?XC  
//分割文件 flqr["czwK  
//实例FileSplitterFetch _ymSo`IvR  
//启动FileSplitterFetch线程 cJq{;~  
//等待子线程返回 d7b`X<=@s  
try{ NiVLx_<Pr'  
if(bFirst) X%-hTl  
{ CPNV\qCY  
nFileLength = getFileSize(); \R@}X cqZ  
if(nFileLength == -1) <ZZfN@6  
{ P;25F
 
System.err.println("File Length is not known!"); hl**G4z9q  
} k7*-v/*S  
else if(nFileLength == -2) B^dMYFelJ  
{ xC _3&.  
System.err.println("File is not access!"); N)
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} W%ix|R^2]  
else g~K-'Nw  
{ bt=D<YZk  
for(int i=0;i<nStartPos.length;i++) 8M!9gvcaO  
{ _?{KTgJG  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); /rD9)
 
} bHSoQ \  
for(int i=0;i<nEndPos.length-1;i++) 9<CUm"%J  
{ '!Va9m*w7  
nEndPos = nStartPos[i+1]; B &Z0ZWx  
} n~`jUML2d  
nEndPos[nEndPos.length-1] = nFileLength; oSMIWwg7G  
} F'{T[MA  
} #oEtLb@O  
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//启动子线程 502(CO>  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; mXJG &EA  
for(int i=0;i<nStartPos.length;i++) gf9,/m  
{ 4xs>X7  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }W " i{s/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), B\AyG4J  
nStartPos,nEndPos,i); r\b$/:y<e  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -6F\=  
fileSplitterFetch.start(); u{WI 4n?  
} aF"PB h=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]nIVP  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); f~=e  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", }o GMF~  
nEndPos = " + nFileLength); su\Lxv  
// fileSplitterFetch[nPos.length-1].start(); Aj\m57e,6  
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O&.gc p!  
//等待子线程结束 tJd/uQJ  
//int count = 0; uh)f/)6  
//是否结束while循环 ;2BPEo>z9  
boolean breakWhile = false;  :5^5l  
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while(!bStop) A#~CZQY^$  
{ :8)3t! A  
write_nPos(); u?g;fh6  
Utility.sleep(500); +)( "!@  
breakWhile = true; K nn<q=';G  
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for(int i=0;i<nStartPos.length;i++) 1?p:66WmR  
{ ABtv|0K  
if(!fileSplitterFetch.bDownOver) ) { "}b
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{ +Sv2'& B  
breakWhile = false; Sf`?j  
break; ]Ah<kq2sk  
} &s.-p_4w^D  
} r)qow.+&  
if(breakWhile) $I4JKh  
break; J(,gLl  
}`$({\^w  
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//count++; z*^vdi0  
//if(count>4) viS7+E|O  
// siteStop(); Y-DHW/Z~  
} $*0XWrE  
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System.err.println("文件下载结束！"); [ dVRVm0N  
} m<4tH5};d  
catch(Exception e){e.printStackTrace ();} W6*5e{  
} kf",/?s2Z  
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//获得文件长度 5&U?\YNLa  
public long getFileSize() $>l65)(E\  
{ <M
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int nFileLength = -1; MIAC'_<-e  
try{ gAGcbepX  
URL url = new URL(siteInfoBean.getSSiteURL()); <^A1.o<GN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c30kb  
httpConnection.setRequestProperty("User-Agent","NetFox"); *zPz)3;
 
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int responseCode=httpConnection.getResponseCode(); [ 3SbWwg  
if(responseCode>=400) ^MZ9Zu_  
{ YQfQ[{kp  
processErrorCode(responseCode); Wf$P+i*  
return -2; //-2 represent access is error ,n{|d33  
} +-:G+9L@  
-
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String sHeader; &>auW}r  
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}  
for(int i=1;;i++) )d?L*X~y'  
{ 5fhe{d"si  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); T 3+lYE  
//Utility.log(in.readLine()); pXxpEv  
sHeader=httpConnection.getHeaderFieldKey(i); 9d,2d5Y  
if(sHeader!=null) pB]+c%\  
{ Je~Ybh  
if(sHeader.equals("Content-Length")) ]M9r<x*  
{ ZEU/6.  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));  %?:eURQ  
break; =g^JJpS  
} {B6tGLt#bf  
} `OyYo^+D|.  
else :,dO7dJi  
break; ApAHa]Ccp  
} (=i+{ 3`|  
} DKf:0E8  
catch(IOException e){e.printStackTrace ();} O>L 5 dP  
catch(Exception e){e.printStackTrace ();} >_?Waz%  
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Utility.log(nFileLength); *e-+~/9~  
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return nFileLength; SA16Ng  
} +~\c1|f  

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l+8G6?@]>  
//保存下载信息（文件指针位置） lAPvphO  
private void write_nPos() ! .|\}=[e  
{ r$Ck:Q}  
try{ zc#aQ.  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1 9C=' TMS  
output.writeInt(nStartPos.length); kFHtZS(  
for(int i=0;i<nStartPos.length;i++) </8F  
{ :CAbGs:56  
// output.writeLong(nPos); eyGY8fF8$  
output.writeLong(fileSplitterFetch.nStartPos); `[Xff24(eb  
output.writeLong(fileSplitterFetch.nEndPos); #!X4\+)  
} -F|
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output.close(); 2oFHP_HVfu  
} 564)ha/^(  
catch(IOException e){e.printStackTrace ();} nE3'm[)  
catch(Exception e){e.printStackTrace ();} r8E)GBH-|  
} ]2P*Z6Az  
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//读取保存的下载信息（文件指针位置） ^B|Q&1  
private void read_nPos() ?xuhN G@  
{ l4sFT)}-J  
try{ ,D`iV| (  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 2& l~8,  
int nCount = input.readInt(); 6U`yf&D  
nStartPos = new long[nCount]; ]%PQ3MT.  
nEndPos = new long[nCount]; =i/7&gC  
for(int i=0;i<nStartPos.length;i++) MZX-<p+  
{ O:Fnxp5@  
nStartPos = input.readLong(); _cY!\'  
nEndPos = input.readLong(); &O5W  
} IE-c^'W=}m  
input.close(); ,wN>
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} '
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catch(IOException e){e.printStackTrace ();} (*Jcx:rH  
catch(Exception e){e.printStackTrace ();} RTW4r9~'  
} F`$V H^%V  
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private void processErrorCode(int nErrorCode) XJ|CC.]1u  
{ :i&ZMH,O  
System.err.println("Error Code : " + nErrorCode); z;_fO>u:  
} 9wPc03a  
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//停止文件下载 s^]F4'  
public void siteStop() hDp -,ag{  
{ \)=X=yn2  
bStop = true; El~x$X*  
for(int i=0;i<nStartPos.length;i++) q89#Ftkt  
fileSplitterFetch.splitterStop(); <wt#m`Za  
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} {jX h/`  
} G] -$fz  
//负责部分文件的抓取 G
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**FileSplitterFetch.java 7T]}<aK<c[  
*/ aN7VGc  
package NetFox; x:`]uOp  
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import java.io.*; T [ `t?,  
import java.net.*; /;t42 g9w  
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public class FileSplitterFetch extends Thread { }b-"[TDEF  
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String sURL; //File URL ^mLZT*
  
long nStartPos; //File Snippet Start Position 28u)q2s^W|  
long nEndPos; //File Snippet End Position A7*<,]qT  
int nThreadID; //Thread's ID v,N*vqWS  
boolean bDownOver = false; //Downing is over .z u0GsU=  
boolean bStop = false; //Stop identical VjbRjn5LI  
FileAccessI fileAccessI = null; //File Access interface }ZMbTsm  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException zPp?D_t  
{ +'9l 2DI;  
this.sURL = sURL; VC "66\d&  
this.nStartPos = nStart; w /$4 Rv+S  
this.nEndPos = nEnd; x:W nF62  
nThreadID = id; kw8?:: <  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 6b9 oSY-8  
} `+[e]dH  
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public void run() A"t~ )  
{ CA7ZoMB#  
while(nStartPos < nEndPos && !bStop) hr&&"d {s  
{ m}\G.$h4  
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try{ 6/ir("L
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URL url = new URL(sURL); /3F4t V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Zgt:ZO  
httpConnection.setRequestProperty("User-Agent","NetFox"); NIcPjo  
String sProperty = "bytes="+nStartPos+"-"; h:iK;  
httpConnection.setRequestProperty("RANGE",sProperty); hn
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Utility.log(sProperty); 1b:3'E.#w  
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InputStream input = httpConnection.getInputStream(); T/DKT1P-  
//logResponseHead(httpConnection); A`Vz5WB  
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byte[] b = new byte[1024]; g9> 0N#<  
int nRead; V)M+dhl  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Q}p+/-U\  
{ }D_h*9  
nStartPos += fileAccessI.write(b,0,nRead); L>~wcoB  
//if(nThreadID == 1) 3+mC96wN  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OOy]:t4 /  
} . :Q[Z  
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Utility.log("Thread " + nThreadID + " is over!"); hu (h'  
bDownOver = true; bD_|n!3  
//nPos = fileAccessI.write (b,0,nRead); TwBwqQ)t  
} b/IT8Cm3  
catch(Exception e){e.printStackTrace ();} E/mp.f2!  
} .LDK+c  
} tbHU(#~  
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//打印回应的头信息 xc[LbaBG  
public void logResponseHead(HttpURLConnection con) pPt7M'uL"  
{ %n-:mSus  
for(int i=1;;i++) ]-d:wEj  
{ UR|UGldt_T  
String header=con.getHeaderFieldKey(i); HvSKR1wL\  
if(header!=null) M{gtu'.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); KE3/sw0  
Utility.log(header+" : "+con.getHeaderField(header)); XQAdb"
`  
else tZlz0BY!  
break; *RugVH4  
} 4.)
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} iM;7V*u  
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public void splitterStop() Fm(~Vt;%u  
{ (R)\  
bStop = true;  PZZTRgVc  
} c,%9Fh?(  
/fCj;8T3o  
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} N1r
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/* ^:g8mt  
**FileAccess.java tFLdBv!=:^  
*//文件访问(定位，写) %/KN-*  
package NetFox; <Z%iP{  
import java.io.*; AfmGA9  
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public class FileAccessI implements Serializable{ V?U->0>Z4  
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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 MNURYA=  
RandomAccessFile oSavedFile; k,o|"9H  
long nPos; CAg\-*
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public FileAccessI() throws IOException u4QPO:,a4  
{ b#%s!  
this("",0); @i`*i@g  
} ~IvAnwQ'  
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public FileAccessI(String sName,long nPos) throws IOException KLpu7D5(|  
{ =fmM=@!$<  
oSavedFile = new RandomAccessFile(sName,"rw"); =C{)i@ +  
this.nPos = nPos; _^cDB1I?  
oSavedFile.seek(nPos); <eRE;8C-  
} s'\PU1{  
6u>${}  
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public synchronized int write(byte[] b,int nStart,int nLen) D 3m4:z  
{ .{+<o  
int n = -1; &oJ=   
try{ KKm&~^c  
oSavedFile.write(b,nStart,nLen); 4$Oakl*l  
n = nLen; m89-rR:Kc  
} P/;sZo  
catch(IOException e) ;ru=z@  
{ f\+MnZ4[Qj  
e.printStackTrace (); >r+Dl\R  
} Q]WjW'Ry\  
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return n; C?6wIdp  
} J#DYZ>}Y  
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} J7:VRf|,?(  
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/* @]r,cPx0Y  
**SiteInfoBean.java H8d%_jCr  
*/ *FoH'\=  
package NetFox; 5o;M  
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public class SiteInfoBean { h3rdqx1  
 ^2-2Jz@  
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private String sSiteURL; //Site's URL 61e)SIRz9I  
private String sFilePath; //Saved File's Path PCzC8~t  
private String sFileName; //Saved File's Name LQT^1|nq  
private int nSplitter; //Count of Splited Downloading File X
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public SiteInfoBean() QkbXm[K.Z  
{//nSplitter的缺省值为5 uan%j
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//default value of nSplitter is 5 r}k2n s9  
this("","","",5); 0k"n;:KM8  
} ?@"F\Bv<h  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) !1 :%!7  
{ QcBuUFf!c  
sSiteURL= sURL; px6[1'|g  
sFilePath = sPath; m\QUt ;  
sFileName = sName; (]* Ro 8  
this.nSplitter = nSpiltter; AD_RU_a9  
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} .U.Knn  
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public String getSSiteURL() Pf`HF|NI  
{ o6LeC*  
return sSiteURL; w|$i<OIi)  
}
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public void setSSiteURL(String value) *?sdWRbu}l  
{ DC?U+  
sSiteURL = value; d/I,`  
} aLZza"W  
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, y%!s27  
public String getSFilePath() W&E?#=*X  
{ t>nx#ErS  
return sFilePath; bCWSh~  
} -'SpSy'_  
38<!Dt+S(,  
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public void setSFilePath(String value) X>}-UHKV+  
{ 9FB k|g"U)  
sFilePath = value; C
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} +<#0V
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public String getSFileName() cJ[gCS  
{ dk<) \C"  
return sFileName; PVfky@wl"  
} AQAZ+g(I
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public void setSFileName(String value) a=m4)tjk  
{ ?T.'  q  
sFileName = value; %x(||cq  
} Tj0qq.
 
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public int getNSplitter() 2
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{ o$PY0~#  
return nSplitter; |HT5G=dw
 
} 6uNWL `v  
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public void setNSplitter(int nCount) lVb{bO9-O  
{ [S Jx\Os  
nSplitter = nCount; CKB~&>xx  
} &E&_Z6#  
} [g<rzhC~=  
} O:Y?Wq
^  
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/* B!
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**Utility.java b!lS=zIN  
*/ zDakl*  
package NetFox; 4i]h0_]  
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public class Utility { 0Y|"Bo9
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public Utility() f2*e&+LjTP  
{ WdtZ{H  
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} &/+LY_r'<I  
h*X5Oh6  
//线程睡眠 \mp2LICQg  
public static void sleep(int nSecond) BIQQJLu  
{ 7+'&(^c  
try{ zCz"[9k  
Thread.sleep(nSecond); gUa-6@  
} Fy#y.jK9v  
catch(Exception e) !xD$U/%c  
{ ZovF]jf k  
e.printStackTrace (); ?^} z  
} Ef)v("'w  
} c_~tCKAZ  
n
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//日志 |K.J@zW  
public static void log(String sMsg) %]"eN{Uvn  
{ n{*A<-vL  
System.err.println(sMsg); {JGXdp:SB  
} #[
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public static void log(int sMsg) I+GP`=\  
{ 3[*x'"Q;H  
System.err.println(sMsg); %(}%#-X  
} &P pb2  
} "=Xky,k  
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/* 
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**TestMethod.java prw% )#,  
*/ `ElJL{Rn  
package NetFox; ,DIr&5>p2  
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public class TestMethod { nN'>>'@>  
p3Z[-2I  
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public TestMethod() #&sw%CD  
{ ///xx/weblogic60b2_win.exe boeIO\2}P0  
try{ Xh?J"kjof  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); N"[r_!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); MwE^.6xl{  
SiteFileFetch fileFetch = new SiteFileFetch(bean); v;.w*x8Jw  
fileFetch.start(); ?QRoSQ6  
} XjFaP {  
catch(Exception e){e.printStackTrace ();} @v~<E?Un  
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} o>^@s4t  
1$n!Lj=5  
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public static void main(String[] args) c~)H" n  
{ 3gQ2wP*K  
new TestMethod(); _m@+d>f_  
} 3kW%,d*_  
} (nnIRN<}$  
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