http断点续传简单实现（java)

/* 5k69F  
**SiteFileFetch.java (lb6]MtTHY  
*/ {3hqp*xl  
package NetFox; 9C_*3?6  
import java.io.*; \e<mSR  
import java.net.*; "2a$1Wmj(  
 ]nUR;8  
*4t-e0]j@w  
public class SiteFileFetch extends Thread { e RA7i  
)s7bJjT0=X  
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SiteInfoBean siteInfoBean = null; //文件信息Bean a mqOxb  
long[] nStartPos; //开始位置 4otl_l(`yv  
long[] nEndPos; //结束位置 %y>+1hakkX  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ,eDD:#)$}  
long nFileLength; //文件长度 !\^jt%e&  
boolean bFirst = true; //是否第一次取文件 n@ 4@,  
boolean bStop = false; //停止标志 +'|{1gB  
File tmpFile; //文件下载的临时信息 Z==!C=SBv  
DataOutputStream output; //输出到文件的输出流 KbAR_T1n  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） U;g S[8,p  
public SiteFileFetch(SiteInfoBean bean) throws IOException 2{-!E ^g  
{ abBO93f^  
siteInfoBean = bean; 'WQdr(  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 1 tPVP  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); bpW!iY/q3  
if(tmpFile.exists ()) &|b4\uj9  
{ icE|.[  
bFirst = false; Yt+h2ft!  
read_nPos();  `?|Rc  
} ;1 |x  
else D+sQPymI  
{ "(,2L,Zh  
nStartPos = new long[bean.getNSplitter()]; o)&"Rf  
nEndPos = new long[bean.getNSplitter()]; >7'+ye6z  
} BX[~%iE  
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}
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public void run() jvHFFSK  
{ X*F_<0RC1  
//获得文件长度 m`y9Cuk  
//分割文件 *}cSE|S%  
//实例FileSplitterFetch F2;:vTA>  
//启动FileSplitterFetch线程 6Ps.
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//等待子线程返回 r\2vl8X~  
try{ =gjDCx$|  
if(bFirst) E!J=8C.:  
{ $DebXxJw0l  
nFileLength = getFileSize(); gKo%(6{n~  
if(nFileLength == -1) JoZ(_Jh%m  
{ M;jcUX_{  
System.err.println("File Length is not known!"); (ChD]PWQ  
} T\9~<"P^  
else if(nFileLength == -2) UKtSm%\  
{ V`#.7uUP  
System.err.println("File is not access!"); W.I\J<=V  
} w0w1PE-V=  
else FhkkWWL  
{ O_;Dk W  
for(int i=0;i<nStartPos.length;i++) IP3E9z_L  
{ bsS:"/?>  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); T2FE+A]n9  
} 6N~q`;p0  
for(int i=0;i<nEndPos.length-1;i++) +=BAslk  
{ t"vRc4mf  
nEndPos = nStartPos[i+1]; uO6{r v\  
} =*Z5!W'd  
nEndPos[nEndPos.length-1] = nFileLength; S($Su7g%_  
} }TB(7bbd;  
} i7*EbaYzUO  
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-WJ?:?'  
//启动子线程 4x;_AN  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; .}B(&*9,v  
for(int i=0;i<nStartPos.length;i++) p{D4"Qn+P9  
{ ~" i0x
 
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), HKDID[d0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %NHkDa!  
nStartPos,nEndPos,i); BlA[T%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); QDx$==Fo  
fileSplitterFetch.start(); XH}'w9VynR  
} "Gb1K9A im  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), oczG|_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9(4&KZpK  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", {)8>jxQN  
nEndPos = " + nFileLength); _)T5lEFl=  
// fileSplitterFetch[nPos.length-1].start(); Z?5V4F:f  
g%[c<l9  
LJ)5W  
//等待子线程结束 v59dh (:`Z  
//int count = 0; 6!'3oN{  
//是否结束while循环 W2FD+ wt  
boolean breakWhile = false; ~*A8+@\R  
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ngohtB^]  
while(!bStop) !8NC# s  
{ ^T"vX  
write_nPos(); ?']5dD  
Utility.sleep(500); !$-\;<bZw  
breakWhile = true; fk1ASV<rN  
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for(int i=0;i<nStartPos.length;i++) (8.Z..PH  
{ ?=m?jNa;nC  
if(!fileSplitterFetch.bDownOver) aT>'.*\]  
{ F *FwRj  
breakWhile = false; 6f')6X'x  
break; y{dTp  
} $,+O9
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} ={K`4BD  
if(breakWhile) 35E_W>n  
break; ]QzGE8jp*  
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//count++; h4q|lA6!k8  
//if(count>4) S S2FTb-m  
// siteStop(); &boOtl^  
} ,lZB96r0  
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System.err.println("文件下载结束！"); v?KC%  
} 6d_'4B  
catch(Exception e){e.printStackTrace ();} $STaQ28C  
} $2W%2rZ  
%Ev4]}2C1  
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//获得文件长度 bbrXgQ`s+w  
public long getFileSize() x>Zn?YR,"  
{ -r-k_6QP  
int nFileLength = -1; !o:f$6EA~C  
try{ &YF^j2  
URL url = new URL(siteInfoBean.getSSiteURL()); e" St_z(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3AU;>D^5  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9I6
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:]\([Q+a  
a!=D[Gz*5  
int responseCode=httpConnection.getResponseCode(); z6*X%6,8  
if(responseCode>=400) ,P;Pm68V  
{ r>o63Q:  
processErrorCode(responseCode); $<}$DH
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return -2; //-2 represent access is error vN`klDJgW[  
} 03q5e  
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String sHeader; G3Z)Z)N  
bbE!qk;hEP  
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for(int i=1;;i++) h&KO<
>  
{ 37s0e;aF  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); F(>Np2oi6  
//Utility.log(in.readLine()); h1de[q
)  
sHeader=httpConnection.getHeaderFieldKey(i); aA
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if(sHeader!=null) .(K)?r-g5  
{ o~`/_+  
if(sHeader.equals("Content-Length")) )Y"+,$$>Y`  
{ VK m&iidU  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); pR=@S>!|  
break; F1*>y  
} *\ R ]NV  
} c2l@6<W
w  
else vS;RJg=  
break; CsGx@\jN  
} i@*{27t  
} >*35C`^  
catch(IOException e){e.printStackTrace ();} wW>A_{Y  
catch(Exception e){e.printStackTrace ();} ;U/&I3dzV  
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Utility.log(nFileLength);
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return nFileLength; Tp?7_}tRi  
} 9ijfRqI=x  
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A8muQuj]~~  
//保存下载信息（文件指针位置） "g5^_UP  
private void write_nPos() xQ7l~O b  
{ R@1xt@?  
try{ R0KPZv-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); <sb~ ^B  
output.writeInt(nStartPos.length); =W(Q34  
for(int i=0;i<nStartPos.length;i++) kMIcK4.MH  
{ G/)O@Ugp  
// output.writeLong(nPos); o_izl
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output.writeLong(fileSplitterFetch.nStartPos); Ua
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output.writeLong(fileSplitterFetch.nEndPos); 3Z>Ux3[  
} rD*jp6Cl  
output.close(); Dj"F\j 1  
} l!D}3jD  
catch(IOException e){e.printStackTrace ();} l{*@v=b(  
catch(Exception e){e.printStackTrace ();} 8
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} `'DmDg  
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//读取保存的下载信息（文件指针位置） R$R*'l  
private void read_nPos() Xr,1&"B&t  
{ HY56"LZ$(}  
try{ X]ipI$'+C  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); R)c?`:iUB  
int nCount = input.readInt(); {i;r  
nStartPos = new long[nCount]; u+9hL4  
nEndPos = new long[nCount]; \[;0KV_  
for(int i=0;i<nStartPos.length;i++) xK>*yV  
{ NDN7[7E  
nStartPos = input.readLong(); P0;n9>g  
nEndPos = input.readLong(); iDpSj!x/_  
} ld[I}88$  
input.close(); [*Z;\5&P  
} sU=H&D99  
catch(IOException e){e.printStackTrace ();} ]_)yIi"  
catch(Exception e){e.printStackTrace ();} " s,1%Ltt  
} x`mG<Yt
 
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(^ J
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private void processErrorCode(int nErrorCode) M`0V~P`^  
{ wi!?BCseq  
System.err.println("Error Code : " + nErrorCode); d9k0F OR1  
} R!HXhQ  
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//停止文件下载 `~cqAs}6]Q  
public void siteStop() 9[#pIPxNK  
{ W<'m:dq  
bStop = true; b]e"1Y)D-  
for(int i=0;i<nStartPos.length;i++) L7l FtX+b  
fileSplitterFetch.splitterStop(); t^&Cxh  
)L? P}$+  
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} Ao 'l"-  
} BT !^~S%w  
//负责部分文件的抓取 <NMEGit  
**FileSplitterFetch.java _T60;ZI+^  
*/ 5=-Q4d  
package NetFox; juJklSD  
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import java.io.*; /'SNw?&  
import java.net.*; }PlRx6r@  
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public class FileSplitterFetch extends Thread { i$Ul(?  
}{Pp]*I<A  
4Z3su^XR  
String sURL; //File URL }CSDV9).S  
long nStartPos; //File Snippet Start Position 2DA]i5  
long nEndPos; //File Snippet End Position `bq
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int nThreadID; //Thread's ID MpT8" /.]A  
boolean bDownOver = false; //Downing is over +
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boolean bStop = false; //Stop identical ic:zsuEm  
FileAccessI fileAccessI = null; //File Access interface 2k~l$p>CN!  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException aqZi:icFa  
{ <_L,t 1H{  
this.sURL = sURL; ]h`&&Bqt  
this.nStartPos = nStart; |d2SIyUc  
this.nEndPos = nEnd; j^sg6.Z*  
nThreadID = id; J3V= 46Yc  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 q>_.[+6  
} Wu/]MBM  
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public void run() ktXM
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{ B3`5O[6  
while(nStartPos < nEndPos && !bStop) #lo6c;*m5  
{ U+jOTq8M  
 4\N;2N  
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try{ VBlYvZ;$*  
URL url = new URL(sURL); nF]W,@u"h  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h+H%?:FX  
httpConnection.setRequestProperty("User-Agent","NetFox"); DCO\c9  
String sProperty = "bytes="+nStartPos+"-"; !
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httpConnection.setRequestProperty("RANGE",sProperty); _yx>TE2e  
Utility.log(sProperty); (S5R!lpO  
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InputStream input = httpConnection.getInputStream(); QVT5}OzMt  
//logResponseHead(httpConnection); wU36sCo  
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byte[] b = new byte[1024]; s\(k<Ks  
int nRead; 1-uxC^u?|#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) k"%~"9  
{ S3%FHS  
nStartPos += fileAccessI.write(b,0,nRead); 4Z=_,#h4.  
//if(nThreadID == 1) M/'sl;  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I]t!xA~  
} qr^3R&z!}  
uAq~=)F>,  
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Utility.log("Thread " + nThreadID + " is over!"); OZF rtc+  
bDownOver = true; Sv#XIMw{,  
//nPos = fileAccessI.write (b,0,nRead); X7MM2V  
} I*{nP)^9  
catch(Exception e){e.printStackTrace ();} gCS<iBT(7  
} 'F3f+YD  
} nNV'O(x}  
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6<SAa#@ey  
//打印回应的头信息 }'V5/>m[  
public void logResponseHead(HttpURLConnection con) <c-=3}=U\  
{ )[6U^j4  
for(int i=1;;i++) iC32nY?  
{ wk D^r(hiH  
String header=con.getHeaderFieldKey(i); h8S.x)  
if(header!=null) hbDXo:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); (0r3/t?DQ  
Utility.log(header+" : "+con.getHeaderField(header)); K(rWNO  
else )p0^zv{  
break; ItVWO:x&v  
} BwGfTua  
} #aJ(m&  
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public void splitterStop() @Zu5VpJ  
{ 3?9IJ5p  
bStop = true; py!|\00}  
} `Bp.RXsd*  
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}
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/* Y|f[bw  
**FileAccess.java W?
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*//文件访问(定位，写) gMmaK0uhS  
package NetFox; /GN<\_o=q  
import java.io.*; G
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public class FileAccessI implements Serializable{ 9G#n 0&wRJ  
 :D6 ON"6  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 u(>^3PJ+  
RandomAccessFile oSavedFile; jh%Eq+#S  
long nPos; KNvZm;Q6  
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{ ]{/t-=  
public FileAccessI() throws IOException rdP[<Y9  
{ Ys!82M$g  
this("",0); D9
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} t ;;U}
 
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public FileAccessI(String sName,long nPos) throws IOException ghG**3xr  
{ qFCOUl  
oSavedFile = new RandomAccessFile(sName,"rw"); %~H-)_d20  
this.nPos = nPos; Q:G4Z9Kt  
oSavedFile.seek(nPos); +US!YU  
} +NZ_D#u  
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public synchronized int write(byte[] b,int nStart,int nLen) %+W
{iu[|  
{ _~l5u8{^6  
int n = -1; QC OM_$y  
try{ ifMRryN4  
oSavedFile.write(b,nStart,nLen); kzQ+j8.,U  
n = nLen; +s,=lL  
} zII|9
y  
catch(IOException e) oi&VgnSk  
{ jjRi*^d9  
e.printStackTrace (); y*jp79G  
} YW,tCtI0_  
%op**@4/t\  
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return n; abmYA#  
} >reU#
j  
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} .nf#c.DI  
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/* W fN2bsx>  
**SiteInfoBean.java Uou1
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*/ XSwl Tg  
package NetFox; 7?!d^$B  
#_ ;lf1x!  
x/
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public class SiteInfoBean { 4<w.8rR:A  
{=9,n\85#  
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private String sSiteURL; //Site's URL YlJ@
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private String sFilePath; //Saved File's Path Gi|w}j_  
private String sFileName; //Saved File's Name +6M}O[LP  
private int nSplitter; //Count of Splited Downloading File 9rA0lqr]5  
^qvZXb  
Zgp4`)}:  
public SiteInfoBean() h9&0Z+zs  
{//nSplitter的缺省值为5 DZ3wCLQtK  
//default value of nSplitter is 5 e9Wa<i8  
this("","","",5); hlvK5Z  
} t9GR69v:?  
P-9)38`5  
c)6m$5]  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Y!aSs3c  
{ |#v7/$!  
sSiteURL= sURL; Y#ap*  
sFilePath = sPath; > ym,{EHK  
sFileName = sName; 

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this.nSplitter = nSpiltter; q<x/Hat)  
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%vn"{3y>rF  
} j1Y~_  
6IN e@  
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public String getSSiteURL() yM6pd U]i  
{ @(EAq<5{  
return sSiteURL; v ,i%Q$  
} G{As,`{  
o)M}!MT  
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public void setSSiteURL(String value) (U DnsF  
{ (R,#a *CV  
sSiteURL = value; RN1y^`  
} r8t}TU>C  
`z}?"BW|  
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public String getSFilePath() '0;l]/i.  
{ ?>9/#Nv  
return sFilePath; zF`0J  
} M5LfRBO  
z#9aP&8Q  
MVpGWTH@F  
public void setSFilePath(String value) !NK1MU?T)  
{ dM.f]-g  
sFilePath = value;  \{_q.;}  
} ~f2z]JLr:  
3oj' ytxN  
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public String getSFileName() ,C\i^>=  
{ s2p\]|5  
return sFileName; {S]}.7`l9(  
} nQZx=JK  
.D"m@~j7  
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public void setSFileName(String value) '`[&}R  
{ JJ-( Sl  
sFileName = value; P-_6wfg,;>  
} 0(}t8lc  
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public int getNSplitter() KJUH(]>F  
{ tPWLg),  
return nSplitter; Ys9[5@7  
} 4HXo>0  
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public void setNSplitter(int nCount) wD}l$& +  
{ #6aW9GO  
nSplitter = nCount; IZ-1c1   
} yf.~XUk^  
} sRR(`0Zp  
 `,*3[  
se2!N:|R!G  
/* e`_LEv  
**Utility.java ha<[bue  
*/ :as$4|  
package NetFox; K=Z|/Kkh  
|Pax=oJ\M  
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public class Utility { F`W?II?  
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public Utility() dh iuI|?@  
{ :gibfk]C  
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} #$07:UJ  
h 0Q5-EA  
//线程睡眠 x.6:<y  
public static void sleep(int nSecond) !sP{gi#=  
{ <oV(7  
try{ ORw,)l  
Thread.sleep(nSecond); zT]8KA   
} BoWg0*5xb  
catch(Exception e) xwq (N_  
{ nPl?K
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e.printStackTrace (); =z69e%.  
} BhGu!Y6f  
} '[:D$q;  
u'DRN,h+  
//日志 sY Q
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public static void log(String sMsg) :U%W%
  
{ $k%2J9O  
System.err.println(sMsg); 'G4ICtHQ  
} \'D0'\:vz  
cp7=epho  
Hg izW  
public static void log(int sMsg) v>)"HL"XG  
{ sIGMA$EK  
System.err.println(sMsg); K7:)nv E  
} 3yF,ak{Sl  
} 9}<ile7^  
d.d/<  
06Sceq  
/* IueFx u  
**TestMethod.java vMH  
*/ }rw
8PZ9  
package NetFox; x*U)Y  
[!#L6&:a8  
)_S(UVI5  
public class TestMethod { k"zv~`i'  
h2]P]@nW;W  
Yu^4VXp~M%  
public TestMethod() k2tF}  
{ ///xx/weblogic60b2_win.exe }@q`%uzi  
try{ G@X% +$I  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 9-a0:bP  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); C1n>M}b  
SiteFileFetch fileFetch = new SiteFileFetch(bean); xr Jg\to{i  
fileFetch.start(); CXM
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} LYK"(C  
catch(Exception e){e.printStackTrace ();} D.u{~  
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)'cMYC  
} G}raA%  
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public static void main(String[] args) .g<DD)`  
{ .|fHy  
new TestMethod(); "JV_2K_i  
} []1C$.5DD  
} `l[c_%Bm  
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