http断点续传简单实现（java)

/* lz#@_F|.*  
**SiteFileFetch.java unN*L  
*/ kkT=g^D9j  
package NetFox; |JUAR{  
import java.io.*; $L]E< gWrP  
import java.net.*; 1[Jv9S*f/  
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public class SiteFileFetch extends Thread { @A%\;oo  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 59_VC('  
long[] nStartPos; //开始位置 eGrxS;NY  
long[] nEndPos; //结束位置 @7Nc*-SM  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Y-"7R>^I  
long nFileLength; //文件长度 0ARj3
 
boolean bFirst = true; //是否第一次取文件 VsRdZ4  
boolean bStop = false; //停止标志 [k,FJ5X  
File tmpFile; //文件下载的临时信息 _~b]/]|z#N  
DataOutputStream output; //输出到文件的输出流 2s`~<EF N  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） w}(Ht_6q{  
public SiteFileFetch(SiteInfoBean bean) throws IOException HO8x:2m  
{ A0uA\E4q  
siteInfoBean = bean; d a.6Z!a  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); c~Z\|Y`#B  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^ G>/;mZ  
if(tmpFile.exists ()) Jy#21  
{ u6p nO  
bFirst = false; PKNpR  
read_nPos(); v<S?"# ]F=  
} hjoxx F\
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else nTXM/  
{ F='rGQK!1  
nStartPos = new long[bean.getNSplitter()]; }mQh^  
nEndPos = new long[bean.getNSplitter()]; 7|7sA'1cM  
} C@FX[:l@-  
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} i<uk}  
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public void run() y{uN+QS  
{ x5nw/''[2  
//获得文件长度 f5|Ew&1EP  
//分割文件 e^Lt{/  
//实例FileSplitterFetch )XL}u4X  
//启动FileSplitterFetch线程 hXsH9R  
//等待子线程返回 %N-f9o8  
try{ T,Zfz9{n  
if(bFirst) ye1h
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{ 
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nFileLength = getFileSize(); _,9/g^<  
if(nFileLength == -1) 6`
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{ o;Ma)/P  
System.err.println("File Length is not known!"); 9"mcN3x:\e  
} 1Igo9rv  
else if(nFileLength == -2) _0]{kB.$_  
{ hiA%Tq?  
System.err.println("File is not access!"); lip1wR7  
} h4dT N}  
else 9
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{ h$y0>eMWs  
for(int i=0;i<nStartPos.length;i++) )'gO
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{ C'jE'B5b  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Qh. : N  
} J+6bp0RIh  
for(int i=0;i<nEndPos.length-1;i++) /6@Wm?`DB  
{ H-aSLc  
nEndPos = nStartPos[i+1]; C~aNOe WR  
} } h pTS_  
nEndPos[nEndPos.length-1] = nFileLength; Y^W.gGM  
} $s-HG[lX[  
} Z39I*-6F9W  
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c'r7sI%Yi  
//启动子线程 qdeS*rp\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; -P>f2It  
for(int i=0;i<nStartPos.length;i++) w-.=u3  
{ m"Y|xvIA  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  BJi  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2K1odqO#  
nStartPos,nEndPos,i); 2m/=0sb\{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'v*Y7zZ#K  
fileSplitterFetch.start(); .U:DuyT  
} [J.-gN$X@  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zS##YR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); m;"i4!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", =9ISsI\Y6  
nEndPos = " + nFileLength); D.\s mk  
// fileSplitterFetch[nPos.length-1].start(); :{Crc   
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;0f?-W?1  
//等待子线程结束 'YcoF;&[C  
//int count = 0; On{p(|l  
//是否结束while循环 (X"WEp^Q{I  
boolean breakWhile = false; Gf{FFIe
(  
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while(!bStop) _jW}p-j  
{ TZ,kmk#
 
write_nPos(); szy^kj^2  
Utility.sleep(500); b8@gv OB  
breakWhile = true; s
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for(int i=0;i<nStartPos.length;i++) aI6fPQe  
{ ['S
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if(!fileSplitterFetch.bDownOver) &91U(Go  
{ k*8 ld-O  
breakWhile = false; HjO-6F#s  
break; loLN ~6  
} L[Dr[  
} W
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if(breakWhile) aQK>q. t  
break; 2vit{  
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//count++; y0R5YCq\":  
//if(count>4) t(|\3$z  
// siteStop(); x]gf3Tc58  
} 9(>l trA  
S"Dw8_y7}  
cbk|LQ.O  
System.err.println("文件下载结束！"); ? D?XaRb  
}  De>'  
catch(Exception e){e.printStackTrace ();} "@JSF  
} xsq+RBJi  
3UIR^Rh+  
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//获得文件长度 luyU!  
public long getFileSize() +
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{ RQZ|:SvV  
int nFileLength = -1; F;mK)Q-  
try{ }?pY~f  
URL url = new URL(siteInfoBean.getSSiteURL()); HY,+;tf2r  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z2]ySyt]  
httpConnection.setRequestProperty("User-Agent","NetFox"); `2X#;{a:  
c8cV{}7Kb  
]Hp o[IF  
int responseCode=httpConnection.getResponseCode(); fXPD^}?Ux4  
if(responseCode>=400) e7<//~W7W  
{ =U6%Wdth  
processErrorCode(responseCode); S0_#h)  
return -2; //-2 represent access is error BTwLx-p9t  
} m8q3Pp  
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String sHeader; Cc?BJ  
/ ;U  
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for(int i=1;;i++) D2`tWRm0  
{ ic}M)S FD;  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); K0#kW \4`  
//Utility.log(in.readLine()); NM0[yh  
sHeader=httpConnection.getHeaderFieldKey(i); 8#gS{  
if(sHeader!=null) lD;="b  
{ S aCa  
if(sHeader.equals("Content-Length")) BTXS+mvl  
{ [/}y!;3iXM  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); qV%t[>  
break; #OKzJ"g
 
} I<q=lK  
} s}]qlg  
else sbZ$h <  
break; 7a@%^G @!  
} R6ynL([xh  
} :>U2yI  
catch(IOException e){e.printStackTrace ();} %z6.}4h  
catch(Exception e){e.printStackTrace ();} '1lr "}"Q+  
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Utility.log(nFileLength); G:f\wK[  
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return nFileLength; S~QL x  
} x~Egax  
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//保存下载信息（文件指针位置） '/^bO#G:  
private void write_nPos() 4~Ptn/ g  
{ =)Cqjp  
try{ P=:mn>  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?=:wIMV  
output.writeInt(nStartPos.length); =#N;ZG  
for(int i=0;i<nStartPos.length;i++) VZ?"yUZ Id  
{ oyGO!j  
// output.writeLong(nPos); 3"O)"/"Q.  
output.writeLong(fileSplitterFetch.nStartPos); CKShz]1  
output.writeLong(fileSplitterFetch.nEndPos); UXz0HRRS0  
} B!|<<;Da6  
output.close(); ~c>*3*  
} -jc8ku3*  
catch(IOException e){e.printStackTrace ();} 2\flTO2Ny  
catch(Exception e){e.printStackTrace ();} ;\@co5.=  
} olNgtSX  
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), >jBYMJ  
//读取保存的下载信息（文件指针位置） 7tOOruiC  
private void read_nPos() |s&jWM$  
{ <$#b3F"I  
try{ `C~RA,M  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .z/M (  
int nCount = input.readInt(); WPBn?vb0<  
nStartPos = new long[nCount]; HS{a^c%  
nEndPos = new long[nCount]; \atztC{-L>  
for(int i=0;i<nStartPos.length;i++) BlF]-dF\  
{ W\s ]qsLS  
nStartPos = input.readLong(); =HT:p:S  
nEndPos = input.readLong(); Ys@M1o  
} ecK{+Z'G  
input.close(); box(FjrZE  
}
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catch(IOException e){e.printStackTrace ();} G.2ij%Zz  
catch(Exception e){e.printStackTrace ();} cPh U qET  
} p`// *gl  
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private void processErrorCode(int nErrorCode) T:ye2yg  
{ /"A)}>a  
System.err.println("Error Code : " + nErrorCode); S/}6AX#F4  
} 8}m bfuo1  
:3k&[W*  
nJJ9>#<g$  
//停止文件下载 Nf0'>`/  
public void siteStop() %vjLw`  
{ Mg H,"G  
bStop = true; \%nFCK0  
for(int i=0;i<nStartPos.length;i++) `8Y& KVhu  
fileSplitterFetch.splitterStop(); +*2wGAT  
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} s;'XX}Y  
} CmaV>  
//负责部分文件的抓取 ]:CU.M1  
**FileSplitterFetch.java 2|vArRKt  
*/ >
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package NetFox; F+A"-k_\T#  
BU[.P]  
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import java.io.*; ?CB*MWjd  
import java.net.*; mzufl:-=  
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public class FileSplitterFetch extends Thread { S<
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b#U nE  
String sURL; //File URL vn"2"hPF|  
long nStartPos; //File Snippet Start Position 8spoDb.S  
long nEndPos; //File Snippet End Position 2@``=0z  
int nThreadID; //Thread's ID I@Vh
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boolean bDownOver = false; //Downing is over iB[>uW  
boolean bStop = false; //Stop identical tlw$/tMa  
FileAccessI fileAccessI = null; //File Access interface > Y <in/  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException TJ@@kSSbl  
{ 3F'{JP  
this.sURL = sURL; H`/QhE  
this.nStartPos = nStart; =5NrkCk#V  
this.nEndPos = nEnd; 5'f4=J$Z)  
nThreadID = id; 7n*,L5%?]4  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9-;ujl?{  
} R<VNbm;  
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public void run() 5~T`R~Uqb  
{ v.,|#}0 o  
while(nStartPos < nEndPos && !bStop) >AsD6]   
{
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try{ D>9~JHB  
URL url = new URL(sURL); tx}}Kd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); J(*qOG
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httpConnection.setRequestProperty("User-Agent","NetFox"); L/1zG/@  
String sProperty = "bytes="+nStartPos+"-"; l2uh"!
 
httpConnection.setRequestProperty("RANGE",sProperty); (vm&&a@  
Utility.log(sProperty); sS5 ]d8  
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InputStream input = httpConnection.getInputStream(); DA)+)PhY7K  
//logResponseHead(httpConnection); Q3MG+@)S  
8<(qN>R  
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byte[] b = new byte[1024]; Bw-<xwD  
int nRead; T'9I&h%\  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) NNZ%jJy?=,  
{ ":E^&yQ  
nStartPos += fileAccessI.write(b,0,nRead); m+p}Qi8i)  
//if(nThreadID == 1) \u@4eBAV  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [(v?Z`cX\  
} %2Q:+6)  
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Utility.log("Thread " + nThreadID + " is over!"); (9:MIP  
bDownOver = true; 6@pPaq6  
//nPos = fileAccessI.write (b,0,nRead); xW@y=l Cu  
} J2cqnwUV  
catch(Exception e){e.printStackTrace ();} Wz)O,X^  
} 0yW#).D^b  
} `>CHE'_  
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//打印回应的头信息 dz fR ^Gv  
public void logResponseHead(HttpURLConnection con) (.Hiee43  
{ Wbo{v r[2+  
for(int i=1;;i++) ySP1,xq  
{ L/Cp\|~ O  
String header=con.getHeaderFieldKey(i); g_lj/u]P  
if(header!=null) "?Dov/+Q.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4|Z;EAFx  
Utility.log(header+" : "+con.getHeaderField(header)); @UCI^a~w  
else YXE?b@W"  
break; X`km\\*  
} lz>YjK:  
} ^VsX9  
~!( (?8"  
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public void splitterStop() lSv?!2  
{ 2E~WcB  
bStop = true; 61|uvTX  
} Kx.'^y  
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} yZup4#>8  
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/* <<#-IsT  
**FileAccess.java _'9
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*//文件访问(定位，写) [fF0Qa-  
package NetFox; r':wq
 
import java.io.*; :s8^nEK  
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public class FileAccessI implements Serializable{ DG& ({vy  
(XtN3FTY  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 eQh@.U*S)  
RandomAccessFile oSavedFile; ]IbX<  
long nPos; {"Xn`@Y  
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public FileAccessI() throws IOException @c&}\#;  
{ E6"+\-e  
this("",0); hLYy  
} [?rK9I&  
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public FileAccessI(String sName,long nPos) throws IOException )!+M\fT  
{ 8U,VpuQ:  
oSavedFile = new RandomAccessFile(sName,"rw"); E(J@A'cX  
this.nPos = nPos; /.1c<!  
oSavedFile.seek(nPos); Dqss/vw
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} %@/"BF;r  
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public synchronized int write(byte[] b,int nStart,int nLen) RbPD3&.  
{ Q]j[+e  
int n = -1;
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try{ ?f@g1jJP  
oSavedFile.write(b,nStart,nLen); DONXq]f:,"  
n = nLen; ~)!yl. H  
} ~)5NX 4Po  
catch(IOException e) 8<
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{ #-76E  
e.printStackTrace (); vW`Dy8`06  
} "B18|#v  
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return n; \G}02h  
} 0#\K9|.  
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8 xfn$  
} Y0nnn  
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/* L=`QF'Im  
**SiteInfoBean.java *nb `DR  
*/ <2b&AF{En  
package NetFox; F@m]Imn5Dx  
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public class SiteInfoBean { Gn*cphb  
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private String sSiteURL; //Site's URL GYvD*?uBc  
private String sFilePath; //Saved File's Path R _#x  
private String sFileName; //Saved File's Name <( "M;C3y  
private int nSplitter; //Count of Splited Downloading File Hzm<KQ g  
jA<(#lm;  
3y&N}'R(F  
public SiteInfoBean() n7Em t$Hi>  
{//nSplitter的缺省值为5 GnAG'.t-Z  
//default value of nSplitter is 5 }XmrfegF  
this("","","",5); }kJfTsFS  
} |nOqy&B  
;Dh\2! sr  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ++9?LH4S4  
{ ;_$Q~X  
sSiteURL= sURL; m1pge4*  
sFilePath = sPath; )FLDCer  
sFileName = sName; PjwDth A1  
this.nSplitter = nSpiltter; r4YiXss  
&Hz{  
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} VtP^fM^{  
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;$a+ >  
public String getSSiteURL() !sknO53`H`  
{ D.[h`Hkc  
return sSiteURL; 9Wu c1#  
} pyHU+B  
 3o_)x  
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public void setSSiteURL(String value) mS$9D{  
{ [zC1LTXe  
sSiteURL = value; CdEQiu  
} EF>vu+YK  
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public String getSFilePath() _h6j, )  
{ <QuIXA  
return sFilePath; V8w7U:K  
} 8+f{ /  
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}Z/[ "  
public void setSFilePath(String value) uOQ!av2"Rf  
{ RGu`Jk  
sFilePath = value; f-.
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} t]3> X  
J#>)+  
a/\SPXQ/9  
public String getSFileName() x5w5xw  
{ &nV/XLpG  
return sFileName; lQS(\}N  
} ^cUmLzM  
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public void setSFileName(String value) 1 5heLnei  
{ ._E 6?  
sFileName = value; =,BDd$e  
} {})d}dEC  
]Cc3}+(s  
]8n*fo2#  
public int getNSplitter() lGlh/B%  
{
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return nSplitter; /IxoS  
} L[s`8u<_)z  
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E"O6N.}.  
public void setNSplitter(int nCount) AZ9;6Df  
{ CL|d>  
nSplitter = nCount; > `1K0?_  
} &%UZ"CcA  
} <~ Dq8If  
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a Xn:hn~O  
/* AqA.
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**Utility.java >]L
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*/ C3K":JB  
package NetFox; !V'~<&   
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public class Utility { 2M+}o"g  
lC=-1*WH  
9bQD"%ha=d  
public Utility() n2(`O^yd7C  
{ ]')  
Y|
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} 1!%T<!A.  
Yu}[RXC(=  
//线程睡眠 4C#r=Uw`  
public static void sleep(int nSecond) | |u  
{ zH13~\  
try{ Q\nIU7:bZ  
Thread.sleep(nSecond); !X5LgMw^;  
} aBd>.]l?  
catch(Exception e) qOTo p-  
{ j5gL67B  
e.printStackTrace (); `Hx JE"/  
} _ea|E  8  
} wX4gy
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+h)1NX;o1  
//日志 zcy`8&{A<?  
public static void log(String sMsg) y]okOEV0  
{ S l
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System.err.println(sMsg); 1)H;}%[  
} FvJkb!5*e_  
cCuK?3V4K  
kz"QS.${  
public static void log(int sMsg) h+!@`c>)Y  
{ FfX*bqy
 
System.err.println(sMsg);  9+ A~(  
} eJ0Xfw%y%T  
} FfC\uuRe  
T8BewO=}  
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/* ~_F<"
40  
**TestMethod.java uC! dy  
*/ `J$7X  
package NetFox; M1q_gHA  
#Y0ru9
  
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public class TestMethod { Fr_6pEH]}  
d3]<'B:nb  
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public TestMethod() P9o
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{ ///xx/weblogic60b2_win.exe >x1yFwX}-f  
try{ 7fC:'1]G  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 1=_Qj}!1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [;Jq=G8&t  
SiteFileFetch fileFetch = new SiteFileFetch(bean); z?t75#u9.  
fileFetch.start(); 4iv&!hAc;  
} zGwM# -  
catch(Exception e){e.printStackTrace ();} oh7tE$"c  
iOtf7.@  
}OqP`B  
} xnDst
9%  
6@;sOiN+  
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public static void main(String[] args) uE}$ZBiq  
{ X>i{288M3  
new TestMethod(); cAn_:^
 
} A[`2Mnj  
} !-m 'diE  
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