http断点续传简单实现（java)

/* HmW=t}!  
**SiteFileFetch.java i`R(7Z  
*/ ^K"ZJ6?+1  
package NetFox; :q(D(mK  
import java.io.*; Ca X^)  
import java.net.*; 'V1!&Q6  
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public class SiteFileFetch extends Thread { ygMd$0:MN  
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SiteInfoBean siteInfoBean = null; //文件信息Bean "cNg:  
long[] nStartPos; //开始位置 Q*Y4m8wY  
long[] nEndPos; //结束位置 K[*h+Y
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 zUJ
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long nFileLength; //文件长度 
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boolean bFirst = true; //是否第一次取文件 ;4l-M2  
boolean bStop = false; //停止标志 fjcr<&{:  
File tmpFile; //文件下载的临时信息 Bpm,mp4g\#  
DataOutputStream output; //输出到文件的输出流 q?(A!1(u  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） xUQdVrFU  
public SiteFileFetch(SiteInfoBean bean) throws IOException z1kBNOr  
{ g ,`F<CF9  
siteInfoBean = bean; QjI#Cs}w  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); b/z'`?[  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); l
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if(tmpFile.exists ()) ijE<spG  
{ CcBQo8!G  
bFirst = false; lK "'nLL  
read_nPos(); gAj0ukX5  
} tB]`Hj  
else mZ]P[lQ'5  
{ *3!(*F@M,  
nStartPos = new long[bean.getNSplitter()]; X{#bJ  
nEndPos = new long[bean.getNSplitter()]; 7qpzk7X?pR  
} 9z+vFk`  
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} L^6"'#  
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public void run() zMbfV%b  
{ uFz/PDOZ@  
//获得文件长度 JvKO $^  
//分割文件 fdN45in=>  
//实例FileSplitterFetch "&@gX_%  
//启动FileSplitterFetch线程 cLn;,u4  
//等待子线程返回 )uANmThOz  
try{ _MGNKA6JI  
if(bFirst) u
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{ ]U_5\$  
nFileLength = getFileSize(); p 7 ,f6kG  
if(nFileLength == -1) 3gC\{y!8  
{ dv}8YH["  
System.err.println("File Length is not known!"); TViBCed40  
} {F<)z%^  
else if(nFileLength == -2) )>ug{M%g  
{ eH ;Wfs2f  
System.err.println("File is not access!"); o^8*aH)I>Y  
} 4 U3C~J  
else :x8Jy4L  
{ =g/4{IL%  
for(int i=0;i<nStartPos.length;i++) `Q:de~+AM{  
{ H~~7~1"x  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); >/(i3)  
}  AqKHjCI  
for(int i=0;i<nEndPos.length-1;i++) -b@v0%Q2M*  
{ E7V38Z  
nEndPos = nStartPos[i+1]; MomLda V9Q  
} _TtX`b_Z  
nEndPos[nEndPos.length-1] = nFileLength; mfj4`3:NV  
} \El|U#$u'  
} <sm#D"GpP  
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//启动子线程 PthIdaN@  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];
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for(int i=0;i<nStartPos.length;i++) or?0PEx\  
{ {CW1t5$*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0eQ~#~j&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3"^a rK^N  
nStartPos,nEndPos,i); K%98;e9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); pGO|~:E/L  
fileSplitterFetch.start(); eV"dv*R  
} ^wvH,>Yo  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Gtj(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); CkmlqqUHC  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", xR\D(FLVS  
nEndPos = " + nFileLength); z8 hTZU  
// fileSplitterFetch[nPos.length-1].start(); pw0Px  
|Dl*w/n  
sjkWz2]S  
//等待子线程结束 C4&U:y<ju  
//int count = 0; b7?U8/#'  
//是否结束while循环 KC&H*  
boolean breakWhile = false; SNQz8(O  
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Ah6wU|_-g  
while(!bStop) pWWL{@J  
{ %4?SY82  
write_nPos(); qFvg}}^y  
Utility.sleep(500); ~5lKL5w  
breakWhile = true; _
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for(int i=0;i<nStartPos.length;i++) N BV}4  
{ *ah>-}-  
if(!fileSplitterFetch.bDownOver) G3Idxs  
{ 6a "VCE]  
breakWhile = false; ap Fs UsE  
break; *ge].E  
} jA20c(O  
} y0/WA4,  
if(breakWhile) lcu("^{3  
break; FQ;4'B^k]  
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//count++; <;2P._oZ  
//if(count>4) 8QkWgd7y  
// siteStop(); kvMk:.  
} ?b!CV   
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System.err.println("文件下载结束！"); b@nri5noBm  
} .`oJcJ  
catch(Exception e){e.printStackTrace ();} b&\3ps  
} jF%)Bhn(  
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9  
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//获得文件长度 ek<PISlci  
public long getFileSize() hQgk.$g  
{ FRl3\ZDqrb  
int nFileLength = -1; oV0LJ%  
try{ ga4/,   
URL url = new URL(siteInfoBean.getSSiteURL()); OaD Alrm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #6Efev  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3a'Rs{qxn  
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int responseCode=httpConnection.getResponseCode(); =]_d pEEQ  
if(responseCode>=400) fhBO~o+K>  
{ viW~'}^k7  
processErrorCode(responseCode); mF6@Y[/B  
return -2; //-2 represent access is error *G%1_   
} !ol hZ  
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String sHeader; (cOND/S  
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for(int i=1;;i++) yj}bY?4I  
{ 8ktjDs$=.:  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }m=tzHB*  
//Utility.log(in.readLine()); t*Z .e.q+  
sHeader=httpConnection.getHeaderFieldKey(i); kPx]u\  
if(sHeader!=null) P#dG]NMf  
{ baUEsg[~V  
if(sHeader.equals("Content-Length")) w0a+8gexi  
{ u
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); kjLsk-  
break; H(5S Kv5  
} }aHB$}"!  
} aGq_hP   
else 6=Y3(#Ddt  
break; c]AKeq]  
} mhHA!:Y  
} rd&*j^?  
catch(IOException e){e.printStackTrace ();} EmtDrx4!(f  
catch(Exception e){e.printStackTrace ();} U~u6}s]:  
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Utility.log(nFileLength); p`E|SNt/W  
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return nFileLength; >5Q^9 9V  
} nvO%  
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//保存下载信息（文件指针位置） Dg9--wI}I9  
private void write_nPos() ;ZxK3/(7  
{ rQd1Ch  
try{ M-
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output = new DataOutputStream(new FileOutputStream(tmpFile)); Sah<sb=  
output.writeInt(nStartPos.length); }$&T O$LX  
for(int i=0;i<nStartPos.length;i++) mr{k>Un\  
{ K^z5x#Yj  
// output.writeLong(nPos); Y0P}KPD  
output.writeLong(fileSplitterFetch.nStartPos); Hm+6QgCs  
output.writeLong(fileSplitterFetch.nEndPos); ZXssvjWQV}  
} b:}wR*Adc  
output.close(); bik] JIM  
} ?YkO+?}+  
catch(IOException e){e.printStackTrace ();} "xvV'&lQ  
catch(Exception e){e.printStackTrace ();} KRnB[$3F1  
}  m+72C]9  
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//读取保存的下载信息（文件指针位置） haEZp6Z  
private void read_nPos() *#prSS  
{ CO:m]oj  
try{ bBeFL~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); I&'S2=s  
int nCount = input.readInt(); KV^:sxU  
nStartPos = new long[nCount]; ^-e3=&  
nEndPos = new long[nCount]; nK?k<  
for(int i=0;i<nStartPos.length;i++) DU*g~{8T$  
{ +,vJ7  
nStartPos = input.readLong(); F?RCaj  
nEndPos = input.readLong(); {Gk}3u/  
} uNPD~TYN  
input.close(); E5Snl#Gl\0  
} n3HCd-z  
catch(IOException e){e.printStackTrace ();} _-|yCo  
catch(Exception e){e.printStackTrace ();} tKs4}vW  
} ;9!yh\\   
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private void processErrorCode(int nErrorCode) ?FY@fO?es  
{ Y-neD?VN  
System.err.println("Error Code : " + nErrorCode); ySr091Q  
} DiGUxnP  
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:N*q;j>  
//停止文件下载 $ sA~p_]  
public void siteStop() Kd`l[56#  
{ a!^-~pH:  
bStop = true; <M=W)2D7  
for(int i=0;i<nStartPos.length;i++) zal3j^  
fileSplitterFetch.splitterStop(); W{$+mow7S  
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} hZss  
} %WJ{IXlz  
//负责部分文件的抓取 bY"eC i{K  
**FileSplitterFetch.java vZ_DG}n11  
*/ |$.sB|_ N  
package NetFox; ZaNyNxbp>z  
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import java.io.*; 8eS@<[[F#  
import java.net.*; RBv=  
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public class FileSplitterFetch extends Thread { \fM!^  
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String sURL; //File URL <Hr@~<@~  
long nStartPos; //File Snippet Start Position _,K>u6N&  
long nEndPos; //File Snippet End Position yNWbI0a  
int nThreadID; //Thread's ID W"}*Q-8W  
boolean bDownOver = false; //Downing is over <4!&iU+;  
boolean bStop = false; //Stop identical R^u^y{ohr  
FileAccessI fileAccessI = null; //File Access interface [hv3o0".  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <-oRhi4  
{
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this.sURL = sURL; !+
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this.nStartPos = nStart; +poIgjq0  
this.nEndPos = nEnd;  1+i  
nThreadID = id; v0jz)z<#  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 b]s1Q ]V  
} `X.=uG+m  
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public void run() u UVV>An  
{ k>z-Zg  
while(nStartPos < nEndPos && !bStop) "]\":T  
{ BorfEv} SN  
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try{ 5f`XFe$8  
URL url = new URL(sURL); cnUU1Uz>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Nh7!Ah  
httpConnection.setRequestProperty("User-Agent","NetFox"); -)vp&-  
String sProperty = "bytes="+nStartPos+"-"; n]ppO U|[  
httpConnection.setRequestProperty("RANGE",sProperty); c&I,eds  
Utility.log(sProperty); h>5~ (n8  
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InputStream input = httpConnection.getInputStream(); GE3U0w6WbK  
//logResponseHead(httpConnection); Y;/=3T7An  
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TeN1\rA,  
byte[] b = new byte[1024]; #V9hG9%8  
int nRead; OHtZ"^YG  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) hDkqEkq1R  
{ ~NW5+M(u  
nStartPos += fileAccessI.write(b,0,nRead); t+)GB=C  
//if(nThreadID == 1) \tw#pk  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); koWb@V]  
} Y,pS/  
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6>  
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Utility.log("Thread " + nThreadID + " is over!"); zH\;pmWiN9  
bDownOver = true; j n&9<"W  
//nPos = fileAccessI.write (b,0,nRead); A@Yi{&D_Q]  
} pvwnza1  
catch(Exception e){e.printStackTrace ();} @okm@6J*X  
} 4z3$  
} I\4`90uBN  
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//打印回应的头信息 3<'Q`H>  
public void logResponseHead(HttpURLConnection con) v=Bh A9[  
{ Sdu@!<?B  
for(int i=1;;i++) uxJiec`&  
{ [\M?8R$)  
String header=con.getHeaderFieldKey(i); ! {o+B^^  
if(header!=null) O>):^$-K%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); #pn AK  
Utility.log(header+" : "+con.getHeaderField(header)); 90if:mYA  
else K'rs9v"K|  
break; Nm:<rI,^  
} N,+g/o\f  
} #1!BD!u  
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public void splitterStop() EV,NJ3V  
{ yURh4@  
bStop = true; c"&!=@  
} i.dAL)V  
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]}Hv,a   
} ^d$e^cU  
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/* F1[[fH  
**FileAccess.java 3\l9Sf=M|
 
*//文件访问(定位，写) ]~ 8N  
package NetFox; <.B> LU  
import java.io.*; LYT<o FE-  
xcRrI|?eC  
}~,cCtg:o  
public class FileAccessI implements Serializable{ BL^Hj  
PaI63 !  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 o|n0?bThS-  
RandomAccessFile oSavedFile;  hahD.P<  
long nPos;  SSM> ID  
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public FileAccessI() throws IOException ;}9Ws6#XQs  
{ *8eh%3_$h  
this("",0); 1ZW'PXUZ  
} m<LzB_G\  
:<3;7R'5  
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public FileAccessI(String sName,long nPos) throws IOException q'-l;V|  
{ jN{xpd  
oSavedFile = new RandomAccessFile(sName,"rw"); LO*a>9LI  
this.nPos = nPos; GT}#iM  
oSavedFile.seek(nPos); xfQ;5n  
} `ZV'7|  
:H:}t>X6Vo  
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public synchronized int write(byte[] b,int nStart,int nLen) X?xm1|\  
{ c@{^3V##T  
int n = -1; aZ3 #g  
try{ UHszOl  
oSavedFile.write(b,nStart,nLen); _IGa8=~  
n = nLen; TK?N^ly  
} {$=%5  
catch(IOException e) BqAwo  
{ nE.s  
e.printStackTrace (); bGnJ4R3J  
} ebwoMG,B-  
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return n; h0QQP  
} J3E:r_+  
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} j'b4Sbs-f  
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/* #`wfl9tj  
**SiteInfoBean.java j-E>*N}-_  
*/ D"aQbQP  
package NetFox; 6j![m+vo%  
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5 :>  
public class SiteInfoBean { v333z<<S  
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_ L6>4  
private String sSiteURL; //Site's URL DuZ]g#  
private String sFilePath; //Saved File's Path Rzj!~`&N  
private String sFileName; //Saved File's Name {]N?DmF  
private int nSplitter; //Count of Splited Downloading File [NDYJ'VGe  
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@D{[Hj`<  
public SiteInfoBean() !-Q!/
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{//nSplitter的缺省值为5 {D
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//default value of nSplitter is 5 45JLx?rN_  
this("","","",5); +@v} (  
} Li$k<AM  
#Jb$AA!z  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) t$%}*@x7  
{ K?eo)|4)DB  
sSiteURL= sURL; v65r@)\`  
sFilePath = sPath; K",]_+b  
sFileName = sName; b=go"sJ@>(  
this.nSplitter = nSpiltter; Um&@ 0C+L  
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} _~<TAFBr  
Z)~4)71Y:  
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public String getSSiteURL() Ps-d#~4U;  
{ _CT|5wQF<  
return sSiteURL; wpmtv325  
} |Q+v6r(<zZ  
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public void setSSiteURL(String value) Dn!V)T  
{ Fm{y.URo  
sSiteURL = value; |
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} C*<LVW{P  
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public String getSFilePath() Yq.@7cJ  
{ ,^T2hY`  
return sFilePath; 5Ep  
} 3<lDsb(}0A  
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public void setSFilePath(String value) >
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{ %M:"Ai5:  
sFilePath = value; JJO"\^,;~  
} nV1
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public String getSFileName() X} 8U-N6)  
{ $S/8T  
return sFileName; D':A-E
  
} *n\qV*|6bI  
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public void setSFileName(String value) ]5CFL$_Q{  
{ ~*WbMA  
sFileName = value; H2p;J#cv@  
} q3t@)+l>*  
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public int getNSplitter() B7C6Mau  
{ co|0s+%PBq  
return nSplitter;
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} AmFHn  
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public void setNSplitter(int nCount) .l!Z=n|  
{ JKGZ0yn  
nSplitter = nCount; 9:>vl0  
} ~Fh(4'  
} yDrJn* r^  
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"
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/* k5/}S@F8  
**Utility.java t!$/r]XM h  
*/ :yeTzIz]  
package NetFox; ?T&D@Ohsx  
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public class Utility { Kk#@8h>  
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public Utility() t<=L&:<N  
{ I&9B^fF6  
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} :1I,:L  
PC5FfX  
//线程睡眠 6 9Cxh  
public static void sleep(int nSecond) P#C`/%$S  
{ t&0p@xLQ  
try{ xHmc8G$zu  
Thread.sleep(nSecond); DX|kO  
} cW2:D$Pe  
catch(Exception e) ,$Mw/fA  
{ :d;5Q\C`  
e.printStackTrace (); 4C$,X!kzF  
} _<8y^y
mo  
} @QEVl
 
&nss[w$%C  
//日志 gVc[`(@h  
public static void log(String sMsg) bP[/  
{ gDrqs>8  
System.err.println(sMsg); Lv"83$^S9  
} W~qo `r  
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7g$t$cZby,  
public static void log(int sMsg) QZY(S*Up  
{ VmW_,  
System.err.println(sMsg); b({2|R  
} cjL!$OE6  
} ;%)i/MGEB  
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t t=$:}A  
/* (
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**TestMethod.java 2+'&||h  
*/ z"-Urd^O  
package NetFox; ifkA3]  
0-FbV,:;  
+RM3EvglDQ  
public class TestMethod { cGDA0#r  
(8{Z@  
(]JJ?aAF  
public TestMethod() >wn&+%i&  
{ ///xx/weblogic60b2_win.exe rtI4W  
try{
/[IK[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); &HE8O}<>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); REJ}T:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); .F]6uXd  
fileFetch.start(); 0Ec -/   
} gyPF!"!5dq  
catch(Exception e){e.printStackTrace ();} 7J_H Ox#  
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} k;)L-ge9  
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f?]cW h%  
public static void main(String[] args) 6 3HxQH  
{ 0YS*=J"7z  
new TestMethod(); q*T+8O  
} cc>h=%s`  
} -{O2Nv-]]  
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