http断点续传简单实现（java)

/* ~ dmyS?Or  
**SiteFileFetch.java 'N'EC`R  
*/ #O`nQ  
package NetFox; opdi5e)jK  
import java.io.*; lZE x0  
import java.net.*; WM*7p
;t@)  
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%'@&j2j>  
public class SiteFileFetch extends Thread { _[IN9ZC2G  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ;pS Wu9  
long[] nStartPos; //开始位置 6fQQKM@a|  
long[] nEndPos; //结束位置 :Q!U;33aG  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 E}4R[6YD  
long nFileLength; //文件长度 ;v>2z!M  
boolean bFirst = true; //是否第一次取文件 E3sl"d;~  
boolean bStop = false; //停止标志 ?v `0KF  
File tmpFile; //文件下载的临时信息 v(]\o;/O  
DataOutputStream output; //输出到文件的输出流 Tig`4d-%  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） </Q<*@p?  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~#7=gI&p@  
{ 53@*GXzE  
siteInfoBean = bean; s$|GVv1B  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,Q2`N{f  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~B1)!5Z  
if(tmpFile.exists ()) lc#su$xR>  
{ 1kvBQ1+  
bFirst = false; 'I\bz;VT  
read_nPos(); )Q&:$]  
} 9xN4\y6F  
else -
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{ l<!?`V6}  
nStartPos = new long[bean.getNSplitter()]; c$bb0J%  
nEndPos = new long[bean.getNSplitter()]; .$L'Jt
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} Q4}2-}|  
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" :@5|4qK  

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} DF P0WXbOE  
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public void run() tNG0ft%a  
{ }p]8'($  
//获得文件长度 <TC\Nb$
~  
//分割文件 {D 9m//x  
//实例FileSplitterFetch /*B-y
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//启动FileSplitterFetch线程 >01&3-r  
//等待子线程返回 :l'61$=  
try{ :Fm;0R@/k  
if(bFirst) IlN9IF\9L  
{ sy0|=E*;8"  
nFileLength = getFileSize(); 7%b?[}y4  
if(nFileLength == -1) #kR8v[Z  
{ iLIH |P%  
System.err.println("File Length is not known!"); Oc}4`?oy<O  
} ]O,;t>  
else if(nFileLength == -2)  ")q  
{ g+bc4eU  
System.err.println("File is not access!"); -iLp3m<ai  
} >ZTRwy`_(  
else 2/
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{ yM`J+tq  
for(int i=0;i<nStartPos.length;i++) z'z_6]5  
{ ,qz$6oxh\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); x\z*iv  
} p2cwW/^V  
for(int i=0;i<nEndPos.length-1;i++) 
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{ 0hVw=KDO9:  
nEndPos = nStartPos[i+1]; Zi<Y?Vm/,O  
} 0<d9al|J  
nEndPos[nEndPos.length-1] = nFileLength; G~b/!clN  
} ]q~_  
} 8b\XC%k  
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5 Sm9m*/  
//启动子线程
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 
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for(int i=0;i<nStartPos.length;i++) qS1byqq78l  
{ }#]2u|G  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $o2H#"  
nStartPos,nEndPos,i); )(V|d$n  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); olda't  
fileSplitterFetch.start(); v/gxQy+l  
} xvn@zi  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]@LeyT'cY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); pbc<326X"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", *L7&P46  
nEndPos = " + nFileLength); /&1FgSARK  
// fileSplitterFetch[nPos.length-1].start(); }^3CG9%  
c"F3[mrff  
TC[(mf:8  
//等待子线程结束 K{DsGf,  
//int count = 0; mcO/V-\5'  
//是否结束while循环 s9^r[l@W0U  
boolean breakWhile = false;
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9vX~gh{]~  
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while(!bStop) qrdA4S  
{ [9N
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write_nPos(); %)'# d  
Utility.sleep(500); jgpSFb<9F  
breakWhile = true; ZDn5d%  
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for(int i=0;i<nStartPos.length;i++) oyfY>^bs  
{ Ov<EOK+^  
if(!fileSplitterFetch.bDownOver) %)o'9  
{ kn5X:@{  
breakWhile = false; $f>h_8cla  
break; "|k 4<"]  
} STln_'DF'  
} u([|^~H]  
if(breakWhile) r.z=  
break; vIzREu|5  
^mp#7OL  
'DeI]IeP  
//count++; 3fBV SFVS  
//if(count>4) cVb&Jzd  
// siteStop(); oeKVcVP|'&  
} Wxeg(L}E  
azBYh*s=5{  
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System.err.println("文件下载结束！"); f\+E&p.  
} #OMFv.  
catch(Exception e){e.printStackTrace ();} Sdo mG?;kV  
} ahoXQ8c:\}  
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//获得文件长度 ](@HPAG]  
public long getFileSize() _Jt  
{ V9:Jz Q=?`  
int nFileLength = -1; :MPfCiAv  
try{ ,%=SO 82W  
URL url = new URL(siteInfoBean.getSSiteURL());
R`HC EX)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '-KYeT\;  
httpConnection.setRequestProperty("User-Agent","NetFox"); chC= $(5t  
;}>g/lw  
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int responseCode=httpConnection.getResponseCode(); =:"wU  
if(responseCode>=400) '
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{ /$=<"Y7&g  
processErrorCode(responseCode); c>b!{e@*  
return -2; //-2 represent access is error &#< M o  
} ABaK60.O[O  
A||,|He~  
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String sHeader; QW
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for(int i=1;;i++) V] 0T P#  
{ ;R[w}#Sm  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); E#zLm  
//Utility.log(in.readLine()); 2{}8_G   
sHeader=httpConnection.getHeaderFieldKey(i); MBn ZO  
if(sHeader!=null) W/@-i|v  
{ t9eEcqMg  
if(sHeader.equals("Content-Length")) dTrz7ay
H  
{ P _x(`H  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); xP7#`S6W  
break; UP .4#1I  
} \=&F\EV  
} 6* 6 |R93  
else M* 0zvNg  
break; Y/<`C  
} l.Q.G<ol  
} S&J>15oWM`  
catch(IOException e){e.printStackTrace ();} 7R7e3p,K  
catch(Exception e){e.printStackTrace ();} }h+{>{2j  
~?JNI8  
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Utility.log(nFileLength); S;K5JBX0#  
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return nFileLength; hA=}R.gi  
} N;` jz(r  
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A}4 ",  
//保存下载信息（文件指针位置） @j<Q2z^  
private void write_nPos() +5x{|!Pn  
{ 3|Y2BAd  
try{ uGpLh0  
output = new DataOutputStream(new FileOutputStream(tmpFile)); v\2-%  
output.writeInt(nStartPos.length); S| |OSxZ  
for(int i=0;i<nStartPos.length;i++) L\zyBfK}  
{ d6e$'w@(\T  
// output.writeLong(nPos); H7 "r^s]D  
output.writeLong(fileSplitterFetch.nStartPos); cV4]Y(9  
output.writeLong(fileSplitterFetch.nEndPos); 
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} 7g>|e  
output.close(); 5t,X;  
} / ?'FSWDU  
catch(IOException e){e.printStackTrace ();} 1hY%ZsjC  
catch(Exception e){e.printStackTrace ();} j6WDh}#  
} *]:J@KGf  
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//读取保存的下载信息（文件指针位置） BA8g[TA7K  
private void read_nPos() ns#v?D9NF  
{ zF@[S  
try{ \h/)un5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); lhX4MB"  
int nCount = input.readInt(); w>e+UW25Y  
nStartPos = new long[nCount]; u7SC_3R  
nEndPos = new long[nCount]; GuC 9h^[=M  
for(int i=0;i<nStartPos.length;i++) .@0@Y  
{ 2f6BZ8H+Z  
nStartPos = input.readLong(); A,EuUp  
nEndPos = input.readLong(); :_|Xr'n`A  
} y@(EGfI  
input.close(); I9e3-2THfj  
} [!#}#  
catch(IOException e){e.printStackTrace ();} PJT$9f~3;.  
catch(Exception e){e.printStackTrace ();} D?FmlDTr[  
} jx}7/  
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j;I(w [@P  
private void processErrorCode(int nErrorCode) hC4 M}(XM  
{ hka%!W5  
System.err.println("Error Code : " + nErrorCode); nErr&{C  
} >sZ_I?YDs  
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X%5 `B2Wu  
//停止文件下载 ehLn+tg  
public void siteStop() Z<*"sFpAO  
{ yg6o#;  
bStop = true; .Fx3WryF  
for(int i=0;i<nStartPos.length;i++) N85ZbmU~  
fileSplitterFetch.splitterStop(); \Xe{vlo>h  
}~p%e2<  
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} uPC(|U%  
} BSL+Gjj~}  
//负责部分文件的抓取 CM6! 1 7  
**FileSplitterFetch.java c D.;  
*/ 1p$*N  
package NetFox; P$]
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import java.io.*; b`JS&E  
import java.net.*; ?M^qSo=/~  
#xfav19{.  
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public class FileSplitterFetch extends Thread { `(DHa=s1  
noLr185  
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String sURL; //File URL Xpv<v[a  
long nStartPos; //File Snippet Start Position HCx0'|J  
long nEndPos; //File Snippet End Position C$$Zwgy  
int nThreadID; //Thread's ID _pzYmQ  
boolean bDownOver = false; //Downing is over  6@"E*-z$  
boolean bStop = false; //Stop identical EPA 2_  
FileAccessI fileAccessI = null; //File Access interface Q`{Vs:8X  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 8C[eHC*r  
{ I!}V+gu=  
this.sURL = sURL; HH0ck(u_A*  
this.nStartPos = nStart; 6pt|Crvu
 
this.nEndPos = nEnd; ).0p\.W~  
nThreadID = id; ] _W'-B  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 LK!sk5/  
} ]1eZ<le`6  
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public void run() 6,|>;,U7  
{ !&cfX/y8  
while(nStartPos < nEndPos && !bStop) WncHgz  
{ 0l/7JH_@V  
)T?BO  
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try{ -SLk8x  
URL url = new URL(sURL); &/:c?F?l  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); LpI4R  
httpConnection.setRequestProperty("User-Agent","NetFox"); j}K3YfH  
String sProperty = "bytes="+nStartPos+"-"; `Y+R9bd  
httpConnection.setRequestProperty("RANGE",sProperty); 8k+k\V{  
Utility.log(sProperty); #K iqV6E  
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InputStream input = httpConnection.getInputStream(); J|@D @\?7  
//logResponseHead(httpConnection);
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byte[] b = new byte[1024]; ^:,wk7  
int nRead; D&pX0  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) UMT}2d%  
{ (cV1Pmn  
nStartPos += fileAccessI.write(b,0,nRead); ] mK{E~Zll  
//if(nThreadID == 1) p["pGsf  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7#X`D  
} ~yV?*"Hi  
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Utility.log("Thread " + nThreadID + " is over!"); <q Q@OUI   
bDownOver = true; G*~CB\K_  
//nPos = fileAccessI.write (b,0,nRead); 0-57_"
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} BB ::zBg  
catch(Exception e){e.printStackTrace ();} J3B+WD]  
} GiXs`Yt|  
} >6IUle>z  
D9hq$?
  
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//打印回应的头信息 x}=Q)|)]  
public void logResponseHead(HttpURLConnection con) =h+-1zp{M^  
{ /CbiYm  
for(int i=1;;i++) kf#S"[/E  
{ e AaS }g 0  
String header=con.getHeaderFieldKey(i); &7\fj  
if(header!=null) ~y whl'"k  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 2L51H(  
Utility.log(header+" : "+con.getHeaderField(header)); IGab~`c-[  
else W@zu
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break; =.JcIT'  
} fN:FD`  
} sM%l:Fv  
 ':DL  
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public void splitterStop() :)kHXOb.  
{ g1]bI$;  
bStop = true; L>0Pur)[  
} <'BsQHI  
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} 4$U^)\06W  
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pRUQMPn (  
/* r`RLDN!`  
**FileAccess.java ^+k= ;nl  
*//文件访问(定位，写) ou`KkY||  
package NetFox; TefPxvd  
import java.io.*; Y0m?ZVt  
2uV5hSHYe  
e<FMeg7n  
public class FileAccessI implements Serializable{  5PC:4  
%%)y4>I  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 %?[0G,JG  
RandomAccessFile oSavedFile; ! CJ*zZ*  
long nPos; 7KJ0>0~Et  
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public FileAccessI() throws IOException "/2kf)l{4  
{ j |o&T41  
this("",0); Lw1[)Vk}E  
} >hV2p/D  
!,]c}Y{i  
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public FileAccessI(String sName,long nPos) throws IOException BQ70<m2D$  
{ Q&"oh  
oSavedFile = new RandomAccessFile(sName,"rw"); NzeiGj  
this.nPos = nPos; SZ7; } r8  
oSavedFile.seek(nPos); v(Sh+p  
} rw0s$~'  
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o)DO[  
public synchronized int write(byte[] b,int nStart,int nLen) $jv"$0Fc  
{ Y>~jho  
int n = -1; XD_!5+\H1  
try{ In+2~Jw/2!  
oSavedFile.write(b,nStart,nLen); \=&Z_6Mu  
n = nLen; >m{>0k(^`  
} } j;es(~D  
catch(IOException e) z^WY5~?  
{ ~ tN/  
e.printStackTrace (); x~{W(;`!  
} -z se+]O`  
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return n; $+Z2q<UT  
} oEj$xm_}  
{MDM=;WP_  
{ 9\/aXPS  
} =En1?3?  
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_5$L`&  
/* o=xMaA  
**SiteInfoBean.java @e$EwCV,  
*/ YIb7y1\UM  
package NetFox; yUO%
@;  
9jNh%raG|  
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public class SiteInfoBean { FT J{  
>RpMw!NT  
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private String sSiteURL; //Site's URL y-gXGvZ  
private String sFilePath; //Saved File's Path F}1._I`-  
private String sFileName; //Saved File's Name u|D L?c>W  
private int nSplitter; //Count of Splited Downloading File
2pP"dX  
U%;E:|  
2:e7'}\D.  
public SiteInfoBean() nHp$5|r<  
{//nSplitter的缺省值为5 M 8(w+h{  
//default value of nSplitter is 5 aMJ2bu  
this("","","",5); %5@> nC?`[  
} NZFUCD)  
Z J1
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) fRkx ^u P  
{ ocp  
sSiteURL= sURL; b5f+q:?{  
sFilePath = sPath; Vh]=sd<F  
sFileName = sName; =@X?$>'  
this.nSplitter = nSpiltter; CUBL/U\=  
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} m#RMd,'X  
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public String getSSiteURL() &+H\ST(/  
{ >enP~uW[#  
return sSiteURL; 'AmA3x)9u  
} /BhP`a%2Q  
7_lgo6  
^$RpP+d  
public void setSSiteURL(String value) EZhk(LE  
{ n3 Rf:j^R  
sSiteURL = value; P4c}@Mq3  
} 8p1:dTI5Pb  
(Fq]y5  
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public String getSFilePath() u^x<xw6f  
{ !vHCftKel  
return sFilePath; uv{*f)j/d  
} F*NHy.Y  
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public void setSFilePath(String value) ^1aY,6I:  
{ gI@nE:(m  
sFilePath = value; GSH
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} v`:!$U* H=  
%%h.`p1  
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public String getSFileName() Wv,?xm  
{ %(s2{$3  
return sFileName; H;Gs0Qi;  
} L[Wi[S6=)g  
7~QAprwVS  
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public void setSFileName(String value) Q2Uk0:M  
{ XZ3M~cDq  
sFileName = value; Uf?+oc'{  
} m}6>F0Kv  
_LWMz=U=J/  
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public int getNSplitter() ^lK!tOeO  
{ =Fq{#sC>  
return nSplitter; LVL#qNIu  
} hIa,PZ/Q  
i9peQ61{  
eV0eMDY5  
public void setNSplitter(int nCount) V{}TG]  
{ v)*eLX$  
nSplitter = nCount; 7CX5pRNL  
} DnF|wS  
} x"Ij+~i{l  
s(MdjWw  
0zA:
?}  
/* C"k]U[%{  
**Utility.java NpGz y`&b  
*/ |Y2n6gkH[  
package NetFox; 1Va@w  
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public class Utility {  BfW@f  
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public Utility() :"+3Uk2  
{ 4@M
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} x\G<R; Q  
~k ]$J|}za  
//线程睡眠 ;$4: &T  
public static void sleep(int nSecond) )_Iu7b  
{ j~hvPlho  
try{ >vuR:4B  
Thread.sleep(nSecond); ]:4\rBR3  
} 9*CRMkPrd  
catch(Exception e) 2W63/kRbU  
{ A5G@u}YS5  
e.printStackTrace (); ORfMp'uP=  
} ~jC$C2A0  
} tA K=W$r  
.5#+)] l  
//日志 pq
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public static void log(String sMsg) `O?j -zR  
{ lhF)$M  
System.err.println(sMsg); 6N.MCB^  
} >5Sm.7}R  
cvV8;  
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public static void log(int sMsg)  t&
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{ ~A*$+c(  
System.err.println(sMsg); @8SA^u0  
} qwd T=H  
} t y%Hrw  
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nz  
s09&A]G  
/* kM(,8j  
**TestMethod.java 2K{)8;^  
*/ +?0r%R%\  
package NetFox;
?a~#`<  
5>h# hcL  
m=MM  
public class TestMethod { AD"L
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t\-;n:p-  
qB3=wFI  
public TestMethod() oX6()FR  
{ ///xx/weblogic60b2_win.exe !f#[4Xw  
try{ PtOYlZTe?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); <+ckE2j  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); %r:Uff@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); kBrU%[0O  
fileFetch.start(); =UZm4=T  
} J-~:W~Qx4N  
catch(Exception e){e.printStackTrace ();} dijHi  
WNiM&iU  
#!]~E@;E  
} |Q#CQz  
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8?$XT  
public static void main(String[] args) 8Y~\:3&1<  
{ Hr=?_Un"  
new TestMethod(); I<$m%  
} %Yny/O\e%  
} e `IL7$  
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