http断点续传简单实现（java)

/* Cu)%s  
**SiteFileFetch.java S<2CG)K[  
*/ dw{#||  
package NetFox; SoXX}<~E4  
import java.io.*; .g(\B  
import java.net.*; Pq[0vZ_}dN  
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public class SiteFileFetch extends Thread { i5>J  
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SiteInfoBean siteInfoBean = null; //文件信息Bean c'TiWZP~  
long[] nStartPos; //开始位置 Y*5@|Q  
long[] nEndPos; //结束位置 M&}oat*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _Vk,&'  
long nFileLength; //文件长度 Z;"4$@|qE  
boolean bFirst = true; //是否第一次取文件 ^w&5@3d  
boolean bStop = false; //停止标志 O3<Y_I^  
File tmpFile; //文件下载的临时信息 c4qp3B_w  
DataOutputStream output; //输出到文件的输出流 ^J#*n;OQ3A  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） m_r@t*  
public SiteFileFetch(SiteInfoBean bean) throws IOException x[.z"$T@  
{ r[UyI3(i^  
siteInfoBean = bean; b.%B;qB  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @kCD.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .JD4gF2N  
if(tmpFile.exists ()) mER8> <  
{ VFO&)E/-  
bFirst = false; "t%1@b*u  
read_nPos(); O0=,&=i  
} z6L>!=  
else %Zv(gI`A  
{ I 1VEm?CQ  
nStartPos = new long[bean.getNSplitter()]; ?-.Ep0/  
nEndPos = new long[bean.getNSplitter()]; TYJnQ2m  
} Ls$g-k%c@Q  
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} HhY2`P8  
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public void run() xP5mL3j  
{ ;+TF3av0zq  
//获得文件长度 g.`t!6Hc  
//分割文件 wC
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//实例FileSplitterFetch :)+@qxTy  
//启动FileSplitterFetch线程 )kY_"= d  
//等待子线程返回 23u1nU[0  
try{ ffoo^1}1  
if(bFirst) 4MF}FS2)  
{ b/n8UxA  
nFileLength = getFileSize(); ` HE:D2b  
if(nFileLength == -1) b0z{"  
{ eB/hyC1  
System.err.println("File Length is not known!"); W_f"Gk  
} #iqhm,u7D  
else if(nFileLength == -2) yOn2}Z  
{
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System.err.println("File is not access!"); ttAVB{kdo  
} beHCEwh  
else G(|(y=ck  
{ EkB6- nz  
for(int i=0;i<nStartPos.length;i++) `S/1U87  
{ ]\9B?W(#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); OL ]T+6X  
} )zL"r8si  
for(int i=0;i<nEndPos.length-1;i++) XB!`*vZ/<  
{ }r<@o3t  
nEndPos = nStartPos[i+1]; \Q?|gfJH  
} M\.T 0M_  
nEndPos[nEndPos.length-1] = nFileLength; [nPzhXs  
} h7W%}6Cqkw  
} f'i8Mm4IL  
=Q=&Ucf_  
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//启动子线程 GZhfA ;O,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3EW f|6RI  
for(int i=0;i<nStartPos.length;i++) UN .[,
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{ 2Fp]S a  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d`],l\oC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {+UNjKQC  
nStartPos,nEndPos,i); 
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _]~ht H  
fileSplitterFetch.start(); 84oW  
} o|*|  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m9<[bEO<$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7s fuju(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 9bcyPN  
nEndPos = " + nFileLength); E[Ws} n.  
// fileSplitterFetch[nPos.length-1].start(); ga1gd~a  
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j+B5m:ExfI  
//等待子线程结束 6quWO2x  
//int count = 0; 5t5S{aCDr  
//是否结束while循环
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boolean breakWhile = false; uI-76  
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while(!bStop) Mb2 L32  
{ )}it,<  
write_nPos(); V8U`%/`N  
Utility.sleep(500); Nec(^|[  
breakWhile = true; :_YG/0%I  
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% x*Ec[l  
for(int i=0;i<nStartPos.length;i++) 3ws(uF9$  
{ Iv|WeSL.  
if(!fileSplitterFetch.bDownOver) "KI,3g _V  
{ 53+rpU_  
breakWhile = false; d_7Xlp@  
break; gjN!_^_  
} 46?F+,Rzl  
} U#]eN[  
if(breakWhile) r5qx! >  
break; 
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=5=Vm[  
//count++; y>cmKE  
//if(count>4) w3bH|VnU8;  
// siteStop(); 5NvyK[w]  
} UV8r&O  
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System.err.println("文件下载结束！"); QKaj4?p$|S  
} ut5!2t$c  
catch(Exception e){e.printStackTrace ();} 6ewOZ,"j"4  
} a&c#* 9t{  
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1 l*(8!_  
//获得文件长度 q{+poVX  
public long getFileSize() Yg,WdVI&@  
{ 56 kgL;$h  
int nFileLength = -1; FR6I+@ oX~  
try{ ]%Yis=v  
URL url = new URL(siteInfoBean.getSSiteURL()); 5eSTT#[+R  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); sv6U%qV  
httpConnection.setRequestProperty("User-Agent","NetFox"); DMxS-hl  
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int responseCode=httpConnection.getResponseCode(); irw
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if(responseCode>=400) <^q"31f  
{ =ObtD"  
processErrorCode(responseCode); ~q|e];tA  
return -2; //-2 represent access is error H!>oLui  
} .&}4  
95 .'t}  
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String sHeader; MMr7,?,$  
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for(int i=1;;i++) ?_j6})2zY  
{ c@#zjJhW]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); sCCr%r]zL  
//Utility.log(in.readLine()); xPJJ !mY  
sHeader=httpConnection.getHeaderFieldKey(i); nK'8Mo  
if(sHeader!=null) H1j6.i}q  
{ vG_v89t!ex  
if(sHeader.equals("Content-Length")) <07W&`Dw  
{ sr@XumT  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); K/d&c]  
break; ^W[`##,{Od  
} NE%yv,B  
} C(*@-Npf[  
else W (c\$2`  
break; g+r{>x  
} BCZnF /Zo  
} @=#s~3  
catch(IOException e){e.printStackTrace ();} Z*aU2Kr`;  
catch(Exception e){e.printStackTrace ();} `"":  
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Utility.log(nFileLength); -XIvj'u  
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return nFileLength; safS>wM]  
} ~I|R}hS  
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//保存下载信息（文件指针位置） YIUmCx0a  
private void write_nPos() &Wz:-G7<n  
{ +pViHOJu&V  
try{ (ai-n,y  
output = new DataOutputStream(new FileOutputStream(tmpFile)); |A/_Qe|s2  
output.writeInt(nStartPos.length); PjZvLK@a9)  
for(int i=0;i<nStartPos.length;i++) J*&=J6  
{ /~huTKA}  
// output.writeLong(nPos); LF.~rmPa  
output.writeLong(fileSplitterFetch.nStartPos); HtYR 0J  
output.writeLong(fileSplitterFetch.nEndPos); 4m!3P"$  
} cE>/iZc  
output.close(); }e=GvWGa  
} Pc4cSw#5  
catch(IOException e){e.printStackTrace ();} 1g
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catch(Exception e){e.printStackTrace ();} J7^T!7V.  
} (wF$"c3'{  
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//读取保存的下载信息（文件指针位置） @5VZ   
private void read_nPos() kGiw?~t=%  
{  !Ocg  
try{ tU/NwA"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); a(T4WDl^  
int nCount = input.readInt(); }M@Jrq+7  
nStartPos = new long[nCount]; 3v+}YT{>b  
nEndPos = new long[nCount]; L\CM);y  
for(int i=0;i<nStartPos.length;i++) <U`Nb) &  
{ tS|zf,7  
nStartPos = input.readLong(); ^l9 *h  
nEndPos = input.readLong(); jV&W[xKa  
} E?D{/k,zZ  
input.close(); FGhr
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} 0M2+?aKif  
catch(IOException e){e.printStackTrace ();} Xtnmh)'K~#  
catch(Exception e){e.printStackTrace ();} 'z!#E!i  
} f|1FqL+T]  
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private void processErrorCode(int nErrorCode) <%uZwk>#  
{ rWKLxK4oU  
System.err.println("Error Code : " + nErrorCode); \1D,Kx;Cb  
} S%#Mu|  
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u`,R0=<
4  
//停止文件下载 A_U0HVx_  
public void siteStop() K
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{ Bin&:%|9?  
bStop = true; >.~k?_Of  
for(int i=0;i<nStartPos.length;i++) 5{aQ4H>~tx  
fileSplitterFetch.splitterStop(); 4GA-dtyV&  
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} [N+ruc?)  
}
* xXc$T  
//负责部分文件的抓取 2;r^~:  
**FileSplitterFetch.java urjp&L&  
*/ m|FONQ,@D  
package NetFox; LOkDx2@g  
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import java.io.*; 4>`w9  
import java.net.*; bGO_y]Pc  
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public class FileSplitterFetch extends Thread { cNCBbOMr  
r T$g^  
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String sURL; //File URL V t
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long nStartPos; //File Snippet Start Position >m{-&1Tx  
long nEndPos; //File Snippet End Position vA~hkkj{  
int nThreadID; //Thread's ID 7
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boolean bDownOver = false; //Downing is over A1T;9`E  
boolean bStop = false; //Stop identical sJ()ItU5i
 
FileAccessI fileAccessI = null; //File Access interface ~3]8f0^%m  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException W7>_nK+g?  
{ %'5wwl  
this.sURL = sURL; ~,1X>N"
  
this.nStartPos = nStart; <rxem(PPu  
this.nEndPos = nEnd; 1H@F>}DP  
nThreadID = id; $R36`wk  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 `o'sp9_3  
} nwH|Hs riU  
 1uzfV)  
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public void run() J1MnkxJmpQ  
{ #R|4(HlL  
while(nStartPos < nEndPos && !bStop) b~echOj  
{ +Q&@2 oY"  
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try{ NKYyMHv6  
URL url = new URL(sURL); n&&y\?n  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); g;@PEZk1  
httpConnection.setRequestProperty("User-Agent","NetFox"); Pfy;/}u^c  
String sProperty = "bytes="+nStartPos+"-"; <!$Cvx\U  
httpConnection.setRequestProperty("RANGE",sProperty); wt,N<L  
Utility.log(sProperty); rMloj8O*  
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InputStream input = httpConnection.getInputStream(); izA3INT  
//logResponseHead(httpConnection); ZH:X4!  
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byte[] b = new byte[1024]; AP@d2{"m}  
int nRead; #}?$mxME*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) F@3,>~[%I  
{ f}3bYF  
nStartPos += fileAccessI.write(b,0,nRead); (avaTUMOqy  
//if(nThreadID == 1) rR;Om1 -,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jL>r*=K)%  
} (>23[;.0  
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Utility.log("Thread " + nThreadID + " is over!"); x$sQ .aT  
bDownOver = true; w"J(sVy4  
//nPos = fileAccessI.write (b,0,nRead); ~coG8r"o  
} S?$T=[yY)  
catch(Exception e){e.printStackTrace ();} )I_I?e  
} Kz;VAH  
} c8MNo'h  
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//打印回应的头信息 ) 'KHUa9  
public void logResponseHead(HttpURLConnection con) " OtLJ  
{ Dr609(zg^  
for(int i=1;;i++) QB>e(j%  
{ j>zVC;Sj*  
String header=con.getHeaderFieldKey(i); S/aPYrk>6  
if(header!=null) l.! ~t1i  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Oylw
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Utility.log(header+" : "+con.getHeaderField(header)); %yVZ|d*Q  
else NeP1 #  
break; 7)#/I  
} 4
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} Zup?nP2GkT  
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public void splitterStop() 5`Z#m:+u  
{ 0fNBy^(K  
bStop = true; IA'AA|v  
} up?8Pq*  
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} gS
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# L R[6l  
/* ] $*cmk(Y  
**FileAccess.java &0`L;1R  
*//文件访问(定位，写) q ^?{6}sy  
package NetFox; R<)uvW_@  
import java.io.*; +Xk!)Ge5E*  
9S^-qQH3}  
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public class FileAccessI implements Serializable{ V RL6F2 >6  
O<*iDd`(e  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 (;h\)B!o  
RandomAccessFile oSavedFile; _ U\vHa$#  
long nPos; sQvEUqy9  
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public FileAccessI() throws IOException |bh:x{h  
{ -eya$C  
this("",0); 4^5s\f B  
} {+MMqJCa  
\BDNF<_  
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public FileAccessI(String sName,long nPos) throws IOException li[g =A,  
{ u/AN| y  
oSavedFile = new RandomAccessFile(sName,"rw"); M;OYh  
this.nPos = nPos; T&%>/7I>  
oSavedFile.seek(nPos); Y!H"
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} Tm `CA0@  
0=04:.%D  
= ~yh[@R)  
public synchronized int write(byte[] b,int nStart,int nLen) ~kL":C>2  
{ n| %
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int n = -1; L2N/DB'{  
try{ TBpW/wz/  
oSavedFile.write(b,nStart,nLen); S}+n\pyQ  
n = nLen; LX8vVj8K  
} cX2b:  
catch(IOException e) g8C+j6uR0  
{ 0|cQx VJb  
e.printStackTrace (); 83h6>D b  
} "^\4xI  
D
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return n; ~_q\?pw<$L  
} g7F>o76M  
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} 
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/* gaJS6*P#  
**SiteInfoBean.java h)w<{/p(  
*/ _Nd\Cm  
package NetFox; 79Iz,_  
Z?~7#F~Z`  
C][`Dk\D{  
public class SiteInfoBean { CyE.q^Wm  
=(o$1v/k  
(C!fIRY  
private String sSiteURL; //Site's URL (Az^st/_  
private String sFilePath; //Saved File's Path X(8]9  
private String sFileName; //Saved File's Name 2/GH5b(  
private int nSplitter; //Count of Splited Downloading File 4CDmq[AVS[  
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public SiteInfoBean() 2$jY_{B+x  
{//nSplitter的缺省值为5 ZnQnv@{8l  
//default value of nSplitter is 5 6Cibc.vt  
this("","","",5); }MoCUN)I  
} *yB!^O  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 5~qr+la  
{ `/"z.~8  
sSiteURL= sURL; zdY`c  
sFilePath = sPath; +q3W t|  
sFileName = sName; ).-FuL4Y  
this.nSplitter = nSpiltter; fx*Swv%r  
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@wpm
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} cewQQ&  
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public String getSSiteURL() $XJe)  
{ |/q*Fg[f  
return sSiteURL; L)Kn8  
} PoC24#vS  
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public void setSSiteURL(String value) YyI|^f8C  
{ BKN]DxJ6  
sSiteURL = value; %bddR;c  
} &vLZj  
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public String getSFilePath() nwz}&nR  
{ r8@:Ko= a  
return sFilePath; {
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} pnf3YuB  
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public void setSFilePath(String value) O^LzS&I*  
{ 'A4Lr  
sFilePath = value; ~,ac{%8x  
} :kgwKuhL  
K~[/n<ks  
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public String getSFileName() <n0-zCf  
{ }Za[<t BWS  
return sFileName; 3wD6,x-e   
} ?onZ:s2  
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public void setSFileName(String value) zVp|%&  
{ X^"95Ic  
sFileName = value; eGZIdv1  
} n}a# b%e  
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public int getNSplitter() N-lXC"{)  
{ 8^+Qn/b_%  
return nSplitter; t:W`=^  
} T?Gi;ld7  
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public void setNSplitter(int nCount) Jzh_`jW0l  
{ 89~)nV)  
nSplitter = nCount; KWM.b"WnXr  
} nJrV  
} bD=_44
I  
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/* h}.0Ne  
**Utility.java 'j>Q7M7q{  
*/ )0!hw|0|  
package NetFox; _bFX(~37z?  
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public class Utility { ?f:FmgQk  
_^Rf
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public Utility() E+csK
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{ . [*6W.X  
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} aZ- )w  
zPZy#7/A  
//线程睡眠 ?2QssfB  
public static void sleep(int nSecond) J/WPffqD  
{ vA"yy"B+ V  
try{ dfO84Z} 5  
Thread.sleep(nSecond); iw<+rh*C  
} J$@3,=L6V  
catch(Exception e) -&%#R_RV  
{ {'EQ%H$q  
e.printStackTrace (); 0t'WM=W<!8  
} &U!@l)<  
} HSq&'V  
#*XuU8q?  
//日志 Lw1~$rZg  
public static void log(String sMsg) 3/P
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{ 0vf2wBK'T  
System.err.println(sMsg); pv;}Sv$ ]-  
} l. !5/\  
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|-=^5q5  
public static void log(int sMsg) dKi+~m'w  
{ HS>Z6|uLY  
System.err.println(sMsg); L-",.U*;  
} D'c,z[  
} szGp<x
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/* z'XFwk  
**TestMethod.java 8?J\  
*/ yIOoVi\m  
package NetFox; G"3D"7fa  
U_B"B;ng+  
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public class TestMethod { 9g|o17  
tFO86 !ln  
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public TestMethod() Ws{2+G~  
{ ///xx/weblogic60b2_win.exe aU4v-9@U8  
try{ 2y`rS _2  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); lt`#or"o  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); BMgiXdv.B  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ~f;d3dJ]/  
fileFetch.start(); 58ev (f  
} "O!J6  
catch(Exception e){e.printStackTrace ();} H3nx8R$j](  
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} 2<y!3OeN  
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~kj1L@gy  
public static void main(String[] args) z|x0s0q?  
{ Gn>#Mvq  
new TestMethod(); =TE6R 0b  
} /n"Ib)M  
} b<u   
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