http断点续传简单实现（java)

/* [~f%z(vI  
**SiteFileFetch.java &p=|z2 J  
*/ X7NRQ3P@  
package NetFox; ',*I=JW;  
import java.io.*; (^eE8j/K  
import java.net.*; vh KA8vr  
}\*dD2qNL}  
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public class SiteFileFetch extends Thread { 0O!%NL[,  
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SiteInfoBean siteInfoBean = null; //文件信息Bean d3 fE[/oU  
long[] nStartPos; //开始位置 wvx N6  
long[] nEndPos; //结束位置 &>i+2c~  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 3/}=x<ui  
long nFileLength; //文件长度 L a0H  
boolean bFirst = true; //是否第一次取文件 NZi5rXN  
boolean bStop = false; //停止标志 - FA#hUK$  
File tmpFile; //文件下载的临时信息 sJt&`kZ  
DataOutputStream output; //输出到文件的输出流 |Wi$@sWO  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） +]`MdOu  
public SiteFileFetch(SiteInfoBean bean) throws IOException _BHb0zeot  
{ 9.#\GI ;  
siteInfoBean = bean; ;=F^G?p^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); D GOc!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7KuTC%7  
if(tmpFile.exists ()) '
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{ DWm$:M4z  
bFirst = false; y9Yh%M(  
read_nPos(); e,`+6qP{  
} Z^>3}\_v  
else wH{lp/  
{ c6E@+xU  
nStartPos = new long[bean.getNSplitter()]; JgYaA*1X  
nEndPos = new long[bean.getNSplitter()]; <y-KWWE  
} #E{OOcM  
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} m`4Sp#m  
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public void run() NrNbNFfo  
{ NnrX64|0  
//获得文件长度 jP@H$$-=wH  
//分割文件 ylmf^G@JC  
//实例FileSplitterFetch Kn=P~,FaG3  
//启动FileSplitterFetch线程 ;gK+AU  
//等待子线程返回 J--9VlC'  
try{ c5R58#XK=  
if(bFirst) =WFMqBh<`  
{ ,K3)f.ArYc  
nFileLength = getFileSize(); G/N'8Q)  
if(nFileLength == -1) 5s;HF |2x  
{ ^|>vK,q$I  
System.err.println("File Length is not known!"); 2@uo2]o)  
} /NMd GKr  
else if(nFileLength == -2) !OPa `kSh
 
{ ]{.rx),  
System.err.println("File is not access!"); JV(|7Sk  
} qD7#q]  
else `[VoW2CLH+  
{ 3xp%o5K  
for(int i=0;i<nStartPos.length;i++) 1ncY"S/VO  
{ %]r@vjeyd  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 6$9n_AS  
} oizD:|  
for(int i=0;i<nEndPos.length-1;i++) )/Ee#)z*  
{ ?9OiF-:n  
nEndPos = nStartPos[i+1]; 0Evmq3,9  
} {-7];e  
nEndPos[nEndPos.length-1] = nFileLength; +>44'M^Z|(  
} T% Kj >
-  
} [0Z r z+q  
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//启动子线程
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _dmgNbs
  
for(int i=0;i<nStartPos.length;i++) 2\CFt;fk  
{ ;]KGRT  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), O}Fp\"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), TL1pv l  
nStartPos,nEndPos,i); lRZt
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u"?cmg<.1  
fileSplitterFetch.start(); $X WJxQRUv  
} {S'xZ._=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >|XQfavE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @&83/U?  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 
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nEndPos = " + nFileLength); " F~uTo  
// fileSplitterFetch[nPos.length-1].start(); C.}Z5BwS  
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//等待子线程结束 dAm(uJ  
//int count = 0; LXJ"ct  
//是否结束while循环 =S|SQz5%w  
boolean breakWhile = false; 9fzbR~s  
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while(!bStop) Jc-0.^]E}  
{ r2M._}bF  
write_nPos(); h<$Vry}  
Utility.sleep(500); hGcOk[m 4  
breakWhile = true; r*p<7  
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for(int i=0;i<nStartPos.length;i++) <&t^&6k  
{ }ytc oIuLf  
if(!fileSplitterFetch.bDownOver) m!$"-nh9  
{ ]9l=geZd%;  
breakWhile = false; c03A_2%  
break; 4 "@BbVYR  
} .%M=dL>  
} %)i?\(/  
if(breakWhile) RI')iz?  
break; vaxNF%^~yN  
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//count++; kbI:}b7H  
//if(count>4) n-#?6`>a  
// siteStop(); gk>A  
} ALiA+k N  
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System.err.println("文件下载结束！"); AVZ-g/<  
} _`+ !,kG[  
catch(Exception e){e.printStackTrace ();} g%4-QCZ,  
} K9mL1[B  
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{I@@i8)]  
//获得文件长度 yCf*ts1  
public long getFileSize() 53=VIN]  
{ #?@k=e\  
int nFileLength = -1; ZcYxH|Gn  
try{ i jg'X#E  
URL url = new URL(siteInfoBean.getSSiteURL()); $83TA><a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); OU]!2[7c  
httpConnection.setRequestProperty("User-Agent","NetFox"); so9h6K{qcp  
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int responseCode=httpConnection.getResponseCode(); 5$`i)}:s  
if(responseCode>=400) #6 e  
{ `|8)A)ZVT  
processErrorCode(responseCode); u#/Y<1gn  
return -2; //-2 represent access is error %F3M\)jU  
} %A,4vLe~6  
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String sHeader; 17a'C  
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for(int i=1;;i++) Z
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{ Be68 Fu0  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); RnE=T/VZJ  
//Utility.log(in.readLine()); xx)egy_  
sHeader=httpConnection.getHeaderFieldKey(i); D^E1  
if(sHeader!=null) /(bPc12  
{ Egi<m  
if(sHeader.equals("Content-Length")) 
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{ ]uI#4t~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); W~$YKBW  
break; V)mRG`L  
} (%rO'X  
} ;$ D*,W *  
else ]S[M]-I  
break; 6#MIt:#  
} !_QE|tVeR  
} lM3UjR|@  
catch(IOException e){e.printStackTrace ();} n-be8p)-  
catch(Exception e){e.printStackTrace ();} *r6+Vz  
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Utility.log(nFileLength); \S{ise/U  
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return nFileLength; QeuIAs*_  
} w^s|YF=c  
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//保存下载信息（文件指针位置） (|(#~o]40t  
private void write_nPos() _Jn-#du  
{ _Y4%Fv>@  
try{ t4R=$ km  
output = new DataOutputStream(new FileOutputStream(tmpFile)); aze}koNE  
output.writeInt(nStartPos.length); Ms;:+JI  
for(int i=0;i<nStartPos.length;i++) Z 7rVM  
{ C:\BvPoO  
// output.writeLong(nPos); ~e~iCyW;S  
output.writeLong(fileSplitterFetch.nStartPos); .S>:-j'u  
output.writeLong(fileSplitterFetch.nEndPos); 1@JAY!yoo_  
} Bd*:y qi  
output.close(); Cb~_{$A  
} (, Il>cR4  
catch(IOException e){e.printStackTrace ();} .uG|Vq1v  
catch(Exception e){e.printStackTrace ();} 494"-F6  
} d[;Sn:B  
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//读取保存的下载信息（文件指针位置） 3qR%Mf'  
private void read_nPos() ;HtHN K(o  
{ ?xu5/r<  
try{ rH"
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $TyV< G  
int nCount = input.readInt(); S 'S|k7Lp  
nStartPos = new long[nCount]; Lt$LXE  
nEndPos = new long[nCount]; P!q!+g  
for(int i=0;i<nStartPos.length;i++) (%=[J/F/  
{ ~:~-AXaMT  
nStartPos = input.readLong(); E96FwA5  
nEndPos = input.readLong(); 4loG$l+a1  
} H(GWC[tv  
input.close(); PzbLbH8A  
} *^e06xc:  
catch(IOException e){e.printStackTrace ();} ^"WrE(3  
catch(Exception e){e.printStackTrace ();} d%FD=wm  
} Pb4%"9`  
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private void processErrorCode(int nErrorCode) \_;zm+ <{  
{ &,/_"N"?D  
System.err.println("Error Code : " + nErrorCode); #!(OTeL  
} \yP\@cpY{  
,)^4H>~V  
OBp
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//停止文件下载 BO)K=gl;8  
public void siteStop() :Lu=t3#  
{ W9nmTz\8  
bStop = true; 2x%Xx3!  
for(int i=0;i<nStartPos.length;i++) qOAK`{b  
fileSplitterFetch.splitterStop(); Qxr&zT7f  
#\U;,r  
wN'Q\l+  
} ?.Z4GWyXa
 
} <3i2(k  
//负责部分文件的抓取 ;/T=ctIs  
**FileSplitterFetch.java k`ulDQu
 
*/ u hW@ Y+  
package NetFox; r!A1Sfo4P  
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import java.io.*; !cS A|C  
import java.net.*; Y|$3%t  
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public class FileSplitterFetch extends Thread { AG/?LPJ  
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String sURL; //File URL RS'!>9I  
long nStartPos; //File Snippet Start Position }j9V0`Q  
long nEndPos; //File Snippet End Position d/oxRzk'L  
int nThreadID; //Thread's ID ,ND}T#yTR  
boolean bDownOver = false; //Downing is over +72[*_ <  
boolean bStop = false; //Stop identical xaiA2  
FileAccessI fileAccessI = null; //File Access interface gbF^m`A>%+  
+ q@kRQY;n  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException v53qpqc  
{ Ovu!G q  
this.sURL = sURL; [AgS@^"sf5  
this.nStartPos = nStart; 6bj.z  
this.nEndPos = nEnd; Fv_rDTo  
nThreadID = id; gYb}<[O!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位  {oQ.y  
} ?VVtEmIN  
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public void run() Y)="of  
{ U
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while(nStartPos < nEndPos && !bStop) rq=D[vX\N(  
{ ?U3X,uv5J  
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try{ ipy1tXc  
URL url = new URL(sURL); Qry?h*p+`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); W
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httpConnection.setRequestProperty("User-Agent","NetFox"); *htv:Sr  
String sProperty = "bytes="+nStartPos+"-"; ,|RS]I>X  
httpConnection.setRequestProperty("RANGE",sProperty); )y8 u+5^  
Utility.log(sProperty); 8)n799<.  
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InputStream input = httpConnection.getInputStream(); o1I8l7
 
//logResponseHead(httpConnection); YMGzO  
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byte[] b = new byte[1024]; aH@GhI
^@  
int nRead; :mOHR&2xR%  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) G .PzpBA  
{ 9em?2'ysa  
nStartPos += fileAccessI.write(b,0,nRead); y"5>O|`  
//if(nThreadID == 1) c*iZ6j"iI  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w,uyN  
} .7lDJ2  
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Utility.log("Thread " + nThreadID + " is over!"); LRe2wT>I  
bDownOver = true; +v$,/~$tI  
//nPos = fileAccessI.write (b,0,nRead); DK-V3}`q}  
} e}V3dC^pU  
catch(Exception e){e.printStackTrace ();} dw6U}  
} aE]/w1a  
} kTJz
.  
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//打印回应的头信息 <~wr;"S  
public void logResponseHead(HttpURLConnection con) 5!GL"  
{ fyb:eO}  
for(int i=1;;i++) h?UUd\RU)  
{ sw:o3cC]  
String header=con.getHeaderFieldKey(i); 3RSiu}  
if(header!=null) PWU8 9YXp  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Rn] `_[)*~  
Utility.log(header+" : "+con.getHeaderField(header)); Na6z1&wS  
else <K6:"  
break; S(bYN[U  
} Rwu y!F  
} }V@ * :3w8  
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public void splitterStop() x}acxu 2H7  
{ }ZPO^4H;-  
bStop = true; HfQZRDH  
} /HlLfW  
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} "Q{)H8,E)x  
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/* }cl~Vo-mp  
**FileAccess.java ~3,>TV  
*//文件访问(定位，写) ED0Vlw+1  
package NetFox; *OoM[wEY  
import java.io.*; \
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public class FileAccessI implements Serializable{ R8Kj3wp  
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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 G6l:El&  
RandomAccessFile oSavedFile; *<.{sx^Gk  
long nPos; +>v3&[lGv  
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public FileAccessI() throws IOException ~ 9F rlj  
{ |$hBY
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this("",0); k/U1 :9  
} WAd5,RZ?  

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public FileAccessI(String sName,long nPos) throws IOException <FaF67[Q  
{ 8XS_I{}?  
oSavedFile = new RandomAccessFile(sName,"rw"); HUP~  
this.nPos = nPos; p,(gv])ie  
oSavedFile.seek(nPos); Nft~UggK  
} G=1&:nW'  
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public synchronized int write(byte[] b,int nStart,int nLen) %MA o<,ha  
{ 5X4
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int n = -1; >#9f{  
try{ 8[PD`*w  
oSavedFile.write(b,nStart,nLen); F!
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n = nLen; CrvL[6i  
} 6"OwrJB  
catch(IOException e) \B72 #NR  
{ iZ^tLnc  
e.printStackTrace (); n5Coxvy1  
} c >8IM  
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return n; :NHP,"  
} pm)kocG  
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} =hw&2c  
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/* e1Ne
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**SiteInfoBean.java rAv)k&l  
*/ PUU "k:{  
package NetFox; QsO%m  
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public class SiteInfoBean { vO?\u`vY  
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private String sSiteURL; //Site's URL 6h?v/\  
private String sFilePath; //Saved File's Path )
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private String sFileName; //Saved File's Name bjR:5@"  
private int nSplitter; //Count of Splited Downloading File Ba8 s  
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public SiteInfoBean() I`% ]1{  
{//nSplitter的缺省值为5 UPE9e   
//default value of nSplitter is 5 L  `\>_  
this("","","",5); spX*e1  
} cZb5h 9  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &E/0jxM1  
{ _nn\O3TB  
sSiteURL= sURL; 0%W0vTvL  
sFilePath = sPath; Q>%{Dn\?  
sFileName = sName; PLV-De  
this.nSplitter = nSpiltter; $2
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;YfKG8(0  
?D\6@G:,#@  
} q{c/TRp7  
}hm"49,O  
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public String getSSiteURL() crDm2oA~t  
{ 
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return sSiteURL; ,UveH` n-  
} aAi"  
3}F{a8iIm  
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public void setSSiteURL(String value) U65a_dakk  
{ *"HA=-Z;  
sSiteURL = value; > &VY  
} I'%\ E,  
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public String getSFilePath() o4U[;.?c  
{ Z'<I Is:J  
return sFilePath; R'z -#*[  
} ,,Ia4c  
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public void setSFilePath(String value) Rf4}4ixkj  
{ j@guB:0  
sFilePath = value; d1{%z\u a  
} ExW3LM9(  
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3 {OZdl|  
public String getSFileName() 
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{ Z37%jdr  
return sFileName; l`b%imX  
} &UextGk7  
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public void setSFileName(String value) C]f`  
{ |'SgGg=E  
sFileName = value; oScKL#Hu  
} tB<2mjg  
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vK7J;U+cJ  
public int getNSplitter() scZSnCrR  
{ B s{n  
return nSplitter; Be4n\c.  
} p+y2w{{  
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public void setNSplitter(int nCount) `9vCl@"IV  
{ WWtksi,  
nSplitter = nCount; wc~k4B9"  
} ][[\!og  
} 9bb5?b/  
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/* uupfL>h  
**Utility.java wQR0R~|M  
*/ rl0|)j  
package NetFox; NNTUl$  
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public class Utility { >=VtL4K^  
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95  
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public Utility() ,enU`}9V*  
{ =AVr<kP  
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} y7LT;`A  
4/+P7.}ea-  
//线程睡眠 ?]Wg{\NC6  
public static void sleep(int nSecond) =.9
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{ ,f3Ck*
M  
try{ =(\xe| Q  
Thread.sleep(nSecond); ](tv`1A,Wd  
} ecqL;_{o  
catch(Exception e) 1^R:[L4R`  
{ OLh QS_D  
e.printStackTrace (); w.0
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} Z^l!#"\4m  
} 863PVce",}  

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//日志 TD"w@jBA  
public static void log(String sMsg) "i1r9TLc  
{ NkYU3[m$v  
System.err.println(sMsg); >}|Vmy[/  
} ,K 1X/),  
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fd&=\~1_$  
public static void log(int sMsg) YjTA+1}  
{ n+94./Mh  
System.err.println(sMsg); QmRE<i  
} XL2iK)A  
} #->#mshd4  
n>##,o|Vr#  
[(D^`K<b  
/* xJ[Xmre  
**TestMethod.java $=rLs)  
*/ 8Z1pQx-P2C  
package NetFox; idLCq^jnJ  
*5Aq\g,n  
~K-_]*[x  
public class TestMethod { 4Px  
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+~]:oj  
public TestMethod() ")?NCun>  
{ ///xx/weblogic60b2_win.exe A"W}l)+X  
try{ "JBTsQDj!  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _=d X01  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); S-D=-{@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); #5a'Z+  
fileFetch.start(); l;'#!hC)  
} p#6V|5~8  
catch(Exception e){e.printStackTrace ();} #'2CST  
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} [ta3sEPjs  
@ApX43U(  
),#hBB`ZA  
public static void main(String[] args) -0R;C`(!  
{ r@9qjva  
new TestMethod(); InCo[ 8SI  
} LjOHlT'  
} DD
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