http断点续传简单实现（java)

/* \
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**SiteFileFetch.java $AfM>+GQ`n  
*/ , 0imiv  
package NetFox; $@"l#vJPfc  
import java.io.*; Y-pzy']4  
import java.net.*; .JYaH?  
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public class SiteFileFetch extends Thread { m4aB*6<lq  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ?6Jx@Sh  
long[] nStartPos; //开始位置 [p{#XwN  
long[] nEndPos; //结束位置 s8wmCzB~  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 61.Brp.eP  
long nFileLength; //文件长度 J!0DR4=Xi  
boolean bFirst = true; //是否第一次取文件 !6BW@GeF]  
boolean bStop = false; //停止标志 ^=T$&gD  
File tmpFile; //文件下载的临时信息 g,}_G3[j0m  
DataOutputStream output; //输出到文件的输出流 ^oVs+vC  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Nd`%5%'::  
public SiteFileFetch(SiteInfoBean bean) throws IOException !;0U,!WI  
{ 9 TvV=  
siteInfoBean = bean; -}=i 04^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Rec6c&5_  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); G;&-\0>W  
if(tmpFile.exists ()) 1KMLG=  
{ y&Mr=5:y  
bFirst = false; W{%TlN  
read_nPos(); K&nE_.kbl  
} v 0 }
@  
else n1JRDw"e$$  
{ Ey_" ~OB  
nStartPos = new long[bean.getNSplitter()]; ZYI{i?Te#  
nEndPos = new long[bean.getNSplitter()]; /]=C{)8  
} %70~M_  
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} TcIcS]w%  
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public void run() IOb*GT
b  
{ :E_g"_  
//获得文件长度 z*kutZ:6Y  
//分割文件 MNC*Glj=  
//实例FileSplitterFetch CsTF  
//启动FileSplitterFetch线程 9;_sC  
//等待子线程返回 1nQWW9i
 
try{ \Kl+ 5%L  
if(bFirst) ?3*l{[@J  
{ z54EG:x.7^  
nFileLength = getFileSize(); 2@9Tfm(=  
if(nFileLength == -1) dls ss\c^M  
{ L
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System.err.println("File Length is not known!"); zhpx"{_  
} *RXbc~ H  
else if(nFileLength == -2) L!rw[x  
{ vY%d  
System.err.println("File is not access!"); 9{-EJ)  
} vW
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else K%"5ImM  
{ k
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for(int i=0;i<nStartPos.length;i++) YQ39A_e g  
{ l%?T2Fm3>  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @\0Eu212  
} 99}(~B  
for(int i=0;i<nEndPos.length-1;i++) ?0)&U  
{ F">
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nEndPos = nStartPos[i+1]; oX0D
 
} q8s0AN'@t'  
nEndPos[nEndPos.length-1] = nFileLength; OJ/
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} Ko;{I?c  
} 0}$Hi  
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//启动子线程 CPP` qt%f  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; nyBJb(5"B  
for(int i=0;i<nStartPos.length;i++) c/zJv*}x?  
{ Cz72?[6  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +)j$|x~(A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), c%&:6QniZ  
nStartPos,nEndPos,i); !'mq ?C=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _acE:H  
fileSplitterFetch.start(); I 6<*X  
} Bm"KOr$}-  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1jy9lP=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); I 4,K43|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2C/$Ei^t  
nEndPos = " + nFileLength); #Yr9AVr}K  
// fileSplitterFetch[nPos.length-1].start(); c:-!'l$ !  
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//等待子线程结束 HvM)e.!  
//int count = 0; U}MXT<6  
//是否结束while循环 ^;/b+ /B0  
boolean breakWhile = false; sB^<6W!`(  
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while(!bStop) 2'_:S@  
{ qjf[zF  
write_nPos(); eU<]o< \Qo  
Utility.sleep(500); IG|X!l  
breakWhile = true; o3I Tr';  
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for(int i=0;i<nStartPos.length;i++) `t_W2y
  
{ ,!dh2xNH
^  
if(!fileSplitterFetch.bDownOver) j:E<p_T  
{ KnsT\>[K  
breakWhile = false; J(c{y]`J  
break; YN`H BFH  
} A-4h  
} J.ck~;3  
if(breakWhile) %!du,2  
break; ^@qvl
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//count++; AgFVv5  
//if(count>4) 7b<je=G6PA  
// siteStop(); ai nG6Y<O`  
} =|I>G?g-  
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System.err.println("文件下载结束！"); @6mBqcE'?  
} d!:6[7X6  
catch(Exception e){e.printStackTrace ();} xZ4~Oo@@_'  
} Z00+!Tnd  
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//获得文件长度 P@,nA41,j  
public long getFileSize() KuMF^0V%c  
{ DdVF,  
int nFileLength = -1; kAu+zX>S+  
try{ pek%08VSEU  
URL url = new URL(siteInfoBean.getSSiteURL()); wi4=OU1L)a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1RK=,Wx  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?r?jl;A&  
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int responseCode=httpConnection.getResponseCode(); iVd.f A  
if(responseCode>=400)
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{ *e-A6Sh  
processErrorCode(responseCode); emdoA:w+   
return -2; //-2 represent access is error IRn2|  
} m< 3Ao^I+  
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String sHeader; !!Aj<*%  
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for(int i=1;;i++) ik!..9aB  
{ ^NX"sM0g  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); .!G94b  
//Utility.log(in.readLine()); xA9:*>+>  
sHeader=httpConnection.getHeaderFieldKey(i); >lBD<;T  
if(sHeader!=null) (HSgEs1d  
{ #{=;NuP  
if(sHeader.equals("Content-Length")) x-?{E
  
{ :PtF+{N>  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); pp
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break; jcI&w#re  
} YhY
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} ds&e|VSH;  
else ]ut5S>,"  
break; $ZNu+tn Y  
} $d
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} 3"G>>nC&  
catch(IOException e){e.printStackTrace ();}  8HRmQ  
catch(Exception e){e.printStackTrace ();} e0J6Ae4V[  
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Utility.log(nFileLength); Ma+$g1
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return nFileLength; Z7RiPSdxp  
} m+#iR}*1L  
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//保存下载信息（文件指针位置） r\blyWi  
private void write_nPos() k%E2n:|*  
{ 04*6(L)h*  
try{ Wd
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output = new DataOutputStream(new FileOutputStream(tmpFile)); :"l-KQ0  
output.writeInt(nStartPos.length); \#rI
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for(int i=0;i<nStartPos.length;i++) Vo7dAHHL  
{ OX"j#  
// output.writeLong(nPos); ;\[(- )f!=  
output.writeLong(fileSplitterFetch.nStartPos); y|Ir._bt  
output.writeLong(fileSplitterFetch.nEndPos); 1c;6xc,ub  
} r" K':O6y  
output.close(); lRveHB&V  
} E=cwq"  
catch(IOException e){e.printStackTrace ();} 2e|N@j &  
catch(Exception e){e.printStackTrace ();} ^qC;Nh4F  
} Ton94:9bZ  
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//读取保存的下载信息（文件指针位置） Y& F=t/U2  
private void read_nPos() HU9Sl*/  
{ 4[BG#  
try{ QjC22lW-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); tOOchu?=  
int nCount = input.readInt(); iC*F
  
nStartPos = new long[nCount]; [xT:]Pw}  
nEndPos = new long[nCount]; EZYBeqv  
for(int i=0;i<nStartPos.length;i++) P)uDLFp]  
{ A.D{.a  
nStartPos = input.readLong(); r%e KFS  
nEndPos = input.readLong(); XfKo A0  
} V~ TWKuR  
input.close(); z Nl ,  
} J!5v~<v?-  
catch(IOException e){e.printStackTrace ();} P<Zh XN'  
catch(Exception e){e.printStackTrace ();} lw :`M2P,  
} MCT'Nw@A  
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private void processErrorCode(int nErrorCode) _
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{ b9"jtRTdz  
System.err.println("Error Code : " + nErrorCode); >/#KI~}'N  
} _ib"
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//停止文件下载 7c;9$j  
public void siteStop() jr)7kP@  
{ Ed:eGm }  
bStop = true; 0x9x@gF  
for(int i=0;i<nStartPos.length;i++) iA,kX\nK  
fileSplitterFetch.splitterStop(); >OP+^^oZ<  
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} &|aqP \Q5  
} (708H_  
//负责部分文件的抓取 c)Ic#<e(  
**FileSplitterFetch.java DaH?@Q
 
*/ gZEi]/8_  
package NetFox; 5"/J^"!h  
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import java.io.*; $46{<4.  
import java.net.*; -!)xQvagD.  
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public class FileSplitterFetch extends Thread { 4HAp{
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String sURL; //File URL >I<r)w]  
long nStartPos; //File Snippet Start Position )?2e  
long nEndPos; //File Snippet End Position #eN{!Niy&U  
int nThreadID; //Thread's ID )9S>ZZF  
boolean bDownOver = false; //Downing is over @ a4/ELx  
boolean bStop = false; //Stop identical z`6fotL  
FileAccessI fileAccessI = null; //File Access interface L.T?}o  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException c!hwmy;  
{ cD4 kC>P*  
this.sURL = sURL; TM8=U-A  
this.nStartPos = nStart; huudBc A[  
this.nEndPos = nEnd; 5`]UE7gT  
nThreadID = id; nr)c!8  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 p7ir*r/2  
} c>1RP
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public void run() {"vkji>  
{ W- $a Y2  
while(nStartPos < nEndPos && !bStop) >|Q:g,I  
{ NWfAxkz{/  
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o  
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try{ ez3Z3t`  
URL url = new URL(sURL); fZKt%m  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); kGkA:g:  
httpConnection.setRequestProperty("User-Agent","NetFox"); Y:ldR  
String sProperty = "bytes="+nStartPos+"-"; `imWc"'Ej  
httpConnection.setRequestProperty("RANGE",sProperty); 0GDvwy D1  
Utility.log(sProperty); muW!xY  
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InputStream input = httpConnection.getInputStream(); ?4CNkk=v  
//logResponseHead(httpConnection); Cv)/7vyB8  
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byte[] b = new byte[1024]; 39 Y(!q  
int nRead; @>x pYV  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) zNSu  
{ -;;Z 'NM;8  
nStartPos += fileAccessI.write(b,0,nRead); i{^Z1;Yl  
//if(nThreadID == 1) ^O^:$nXhYy  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); h5kPn~  
} /$"[k2 N  

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Utility.log("Thread " + nThreadID + " is over!"); L?Yoh<  
bDownOver = true; N:VX!w  
//nPos = fileAccessI.write (b,0,nRead); 3E^M?N2oc  
} T88Y qI  
catch(Exception e){e.printStackTrace ();} QIB>rQCceo  
} IgL_5A  
} xKOq[d/8  
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//打印回应的头信息 v=I|O%  
public void logResponseHead(HttpURLConnection con) R)Mt(gFZT_  
{ Xl |1YX1&m  
for(int i=1;;i++) RE3Z%;'  
{ 2h {q h  
String header=con.getHeaderFieldKey(i); E3/:.t  
if(header!=null) 9^F2$+T[:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 8iC:xcN3  
Utility.log(header+" : "+con.getHeaderField(header)); 2WvN2"f3  
else w'7R4  
break; m+$ @'TbP  
} MVCl.o  
} V+wH?H=  
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public void splitterStop() MVv1.6c7Y  
{ {}>n{_  
bStop = true; pN[0YmY#  
} IO.<q,pP!_  
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! o,5h|\  
} ]r]k-GZ$  
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/*
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**FileAccess.java qBk``!|s]  
*//文件访问(定位，写) oCi ~P}r  
package NetFox; CPazEe1S  
import java.io.*; S(eQ{rSs  
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#6S75{rnW"  
public class FileAccessI implements Serializable{ -dTLunv  
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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 _q>SE1j+W=  
RandomAccessFile oSavedFile; K7vw3UwGN  
long nPos; Y\/gU8w/  
|E/L.gdP7  
7_KhV  
public FileAccessI() throws IOException %NHYW\sKX  
{ N1--~e  
this("",0); u~ F;xQ  
} e5
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public FileAccessI(String sName,long nPos) throws IOException NSLVD[
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{ iT)WR90  
oSavedFile = new RandomAccessFile(sName,"rw"); q(z7~:+qNr  
this.nPos = nPos; eTE2J~\  
oSavedFile.seek(nPos); MXAEX2xmme  
} &w~Xa( uu  
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public synchronized int write(byte[] b,int nStart,int nLen) >X Qv?5  
{ mU{4g`Iw  
int n = -1; Nofu7xiDw[  
try{ ?H;{~n?  
oSavedFile.write(b,nStart,nLen); cHvF*A  
n = nLen; zDBD.5R;  
} :pKG\A  
catch(IOException e) o#i ]"  
{ nf%4sIQ*x  
e.printStackTrace (); 7$T8&Mh  
} &&RA4  

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ij)Cm]4(2  
return n; 7t(Y;4<2  
} : 1)}Epo,  
?s{C//  
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} I^0t2[M  
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.5hp0L}  
/* 0'ZYO
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**SiteInfoBean.java mc@M,2@D  
*/ {K.rl%_|N  
package NetFox; {gkwOMW  
2)LX^?7R  
/(6zsq'v|  
public class SiteInfoBean { Q)6va}2ai  
Kr3];(w{  
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private String sSiteURL; //Site's URL B\<ydN  
private String sFilePath; //Saved File's Path a?<?5  
private String sFileName; //Saved File's Name @!H '+c  
private int nSplitter; //Count of Splited Downloading File %O) Z  
af>3V(7  
#vnT&FN0[  
public SiteInfoBean() ?eWJa  
{//nSplitter的缺省值为5 C6k4g75U2  
//default value of nSplitter is 5 ?n*fy  
this("","","",5); i!~>\r\6\  
} 8 lS($@@{  
{rGYRn,  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Xem| o&  
{ i:Mc(mW  
sSiteURL= sURL; lBiovT  
sFilePath = sPath; ep?:;98|t  
sFileName = sName; 0$Ff#8  
this.nSplitter = nSpiltter; _g6wQdxT  
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} m "]!I~jd  
AVpuMNd@  
iSd?N}2,I  
public String getSSiteURL() m`9^.>]P  
{
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return sSiteURL; BvJ=iB<E  
} O
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public void setSSiteURL(String value) %|?1B$s0  
{ !GNXt4D  
sSiteURL = value; 1o#vhk/"+  
} R~c1)[[E  
Jk*QcEE=  
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public String getSFilePath() A}4t9|/K6  
{ C"No5r'K3  
return sFilePath; +!$dO'0nt,  
} @zs1>\J7  
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public void setSFilePath(String value) E4m:1=Nd~]  
{ .;Z.F7{q  
sFilePath = value; 5&%fkZ0  
} j];G*-iv{  
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bA+[{  
public String getSFileName() V85.DK!  
{ yM17H\=  
return sFileName; C38XQLC  
} `(T!>QVW+g  
4 m$sJ  
SY8U"Qc;9  
public void setSFileName(String value) R9E6uz.j  
{ `t9.xB#Z  
sFileName = value; b6Xi  
} nk>8SW^  
q(1r<2  
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public int getNSplitter() <[5#c*A  
{ u2,H ]-  
return nSplitter; E@]sq A  
} ]W|RtdF3.N  
K Dz]wNf  
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public void setNSplitter(int nCount) r4S=I  
{ k) 3s
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nSplitter = nCount; uf?b%:A  
} /sH0x,V  
} :5<#X8>d  
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#}j]XWy  
/* Avd *~  
**Utility.java X=#It&m%s  
*/ }
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package NetFox; w?/f Zx  
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public class Utility { QP<FCmt8  
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1::LN(`<  
public Utility() K /8qB~J*  
{ J2=*-O:  
/6smVz@O  
A{t"M-<  
} Fi/jR0]e2  
[{/$9k-aF?  
//线程睡眠 )ZeLaaP  
public static void sleep(int nSecond) 79a9L{gso  
{ n8Q* _?Z/  
try{ p*!q}%U  
Thread.sleep(nSecond); <YSg~T  
} W`5a:"Vg  
catch(Exception e) oB3q AP  
{ {[N?+ZJD*L  
e.printStackTrace (); cPm~` Zd  
} >z5Oy  
} y78z>(jV  
h%/ssB  
//日志 #9INX`s-  
public static void log(String sMsg) k|l5"&K~.  
{
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System.err.println(sMsg); :`;(p{  
} !2wETs?  
VZIKjrKs  
uGM>C"  
public static void log(int sMsg) K^8@'#S  
{ mUiOD$rO  
System.err.println(sMsg); 8Y7 @D$=w  
} srhFEmgN7)  
} !4_!J (q%  
;i/"$K  
/jvOXS\M  
/* OoE9W  
**TestMethod.java <TL])@da  
*/ G}s;JJax  
package NetFox; Q^vGj</u  
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*  
7 s7}?l9  
public class TestMethod { ,R8n,az  
l,^xX=,  
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public TestMethod() >2nF"?"=  
{ ///xx/weblogic60b2_win.exe 7Onk!NH  
try{ 3V"dG1?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); $m{{,&}k  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); OX`?<@6  
SiteFileFetch fileFetch = new SiteFileFetch(bean); X1O65DMr`g  
fileFetch.start(); f>p; siR)  
} Q})t<l+L  
catch(Exception e){e.printStackTrace ();} }Z^FEd"y  
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} ys/`{:w8p  
gZ1N&/9;  
%bEGv:88s  
public static void main(String[] args) i_|h{JK)  
{ *m iONc  
new TestMethod(); Pu1GCr(  
} >y&[BB7S6  
} bJANZn|H  
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