http断点续传简单实现（java)

/* ?;|$R   
**SiteFileFetch.java ]BP/KCjAI<  
*/ >('L2]4\v  
package NetFox; :{LVS nG  
import java.io.*; &.=d,XKN  
import java.net.*; U-3KuR+0  
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public class SiteFileFetch extends Thread { ;#3!ZB:}  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 1b;Aru~l  
long[] nStartPos; //开始位置 e1}h|HLj  
long[] nEndPos; //结束位置 f>waFu-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 {;Mcor3  
long nFileLength; //文件长度 .+ai dWd  
boolean bFirst = true; //是否第一次取文件 88pz<$  
boolean bStop = false; //停止标志 /Rx%}~x/m  
File tmpFile; //文件下载的临时信息 t{!}^{ "5  
DataOutputStream output; //输出到文件的输出流 emw3cQ  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） RX=C)q2c  
public SiteFileFetch(SiteInfoBean bean) throws IOException 0O
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{ )`-9WCd&  
siteInfoBean = bean; A7+eWg{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *u 3K8"XZ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 6peO9]Zy  
if(tmpFile.exists ()) Nh]eZ3O  
{ ^%#v AS  
bFirst = false; \KLWOj%  
read_nPos(); bW3e*O$V  
}
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else )f(#Fn  
{ -:a 9'dT  
nStartPos = new long[bean.getNSplitter()]; iIcO_ZyA  
nEndPos = new long[bean.getNSplitter()]; "]kaaF$U%  
} V`S6cmwdc\  
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} +X cB5S>  
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public void run() kIrME:  
{ ut& RKr3  
//获得文件长度 +S^Uw'L$=T  
//分割文件 zg)Z2?K|;u  
//实例FileSplitterFetch t \DS}3pv  
//启动FileSplitterFetch线程 V2i*PK X  
//等待子线程返回 lsY5QE:Qrp  
try{ s#)fnNQ,  
if(bFirst) @]Iku6d-  
{ Rc0OEs%7P  
nFileLength = getFileSize(); j@ UIN3  
if(nFileLength == -1) #kA/,qyM  
{ IA$:r@QNx8  
System.err.println("File Length is not known!"); opte)=]J  
} }j+ZF'#  
else if(nFileLength == -2) # T$^{/J  
{ Ls5|4%+&  
System.err.println("File is not access!"); 3PpycJ}  
} -zN*2T  
else QI=",vmau  
{ SD8Q_[rY  
for(int i=0;i<nStartPos.length;i++) _9Iz'-LgB  
{ BNQ~O^R0  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &=<x&4H+  
} A$;U*7TJuO  
for(int i=0;i<nEndPos.length-1;i++) "CT'^d+  
{ fg*IHha  
nEndPos = nStartPos[i+1]; p
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} tL 3]9qfj  
nEndPos[nEndPos.length-1] = nFileLength; 2e/ JFhA  
}
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} ^7Z)/c`"  
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//启动子线程 (](:0H  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ,m8l /wG  
for(int i=0;i<nStartPos.length;i++) xs.>+(@|;  
{ Br`Xw^S  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &h
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [Sg1\UTl  
nStartPos,nEndPos,i); i0v;mc  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); X4Q?]{  
fileSplitterFetch.start(); ] 8+!  
} HP:ee+n  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `rbTB3?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); r_@;eh  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "n}J
6  
nEndPos = " + nFileLength); (Z,v)TOXjV  
// fileSplitterFetch[nPos.length-1].start(); yS@c2I602  
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//等待子线程结束 Ha[Bf*  
//int count = 0; i!*w'[G->Y  
//是否结束while循环 ]- ")r  
boolean breakWhile = false; =;l.<{<VH  
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while(!bStop) 3yszfWr  
{ *l)_&p  
write_nPos(); Q]S~H+eRy  
Utility.sleep(500); ~4
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breakWhile = true; @mSdksB/L  
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for(int i=0;i<nStartPos.length;i++) 47|Lk
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{ =3]}87  
if(!fileSplitterFetch.bDownOver) }%c2u/PQ  
{ GPONCL8(0  
breakWhile = false; ` .|JTm[  
break; (0/,R  
} LBq~?Q.e  
} DJVH}w}9_P  
if(breakWhile) Nj$3Ig"l  
break; qjFz}6  
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//count++; I<`K;El'  
//if(count>4) P^&%T?Y6z  
// siteStop(); )h]~< fU  
} 9t:F![rg  
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System.err.println("文件下载结束！"); Cc/h|4  
} [=7=zV;}4  
catch(Exception e){e.printStackTrace ();} 2BZYC5jy  
} sD H^l)4h  
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//获得文件长度 b`){f\#t  
public long getFileSize() K1>X%f^  
{ 5\gL+qM0  
int nFileLength = -1; GqMa|8j  
try{ c7UmR?m  
URL url = new URL(siteInfoBean.getSSiteURL()); VT8PV5z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?oana%  
httpConnection.setRequestProperty("User-Agent","NetFox"); gqV66xmJ3  
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int responseCode=httpConnection.getResponseCode(); UF0W%Z  
if(responseCode>=400) ,n<t':-  
{ 'n4Ro|kA  
processErrorCode(responseCode); 'w3BSaJi  
return -2; //-2 represent access is error $0$'co"  
} B~+3<#B  
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String sHeader; RfH.WXi  
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for(int i=1;;i++) ,5!&}  
{ +`tl<rg;  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); i[_(0P+Da  
//Utility.log(in.readLine()); yMaU`z  
sHeader=httpConnection.getHeaderFieldKey(i); 5.m&93P  
if(sHeader!=null) }<R,)ZV^G  
{ iO1ir+B\  
if(sHeader.equals("Content-Length")) Z6s-n$dSm  
{ w0qrh\3du  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `EKmp|B_p_  
break; G&,1 NjSi  
} I@Cq<:+(3  
} :btb|^C  
else G"k.sRKu  
break; \ #<.&`8B  
} Dl=9<:6FW  
} =
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catch(IOException e){e.printStackTrace ();} KaVNRS  
catch(Exception e){e.printStackTrace ();} DJ_[{WAV  
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Utility.log(nFileLength); eS#kDa/ %  
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return nFileLength; krqz;q-p~  
} S!+c1q: ].  
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//保存下载信息（文件指针位置） `HVS}}{a  
private void write_nPos() J]&^A$  
{ L& =a(  
try{ :ohGG ,`Dh  
output = new DataOutputStream(new FileOutputStream(tmpFile)); a ?D]]0%  
output.writeInt(nStartPos.length); zT<fTFJ1  
for(int i=0;i<nStartPos.length;i++) I=aoP}_  
{ 6/-]  
// output.writeLong(nPos); *vy^=Yea  
output.writeLong(fileSplitterFetch.nStartPos); O
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output.writeLong(fileSplitterFetch.nEndPos); |Gp!#D0b
  
} L`'#}#O l  
output.close(); /ILj}g'  
} OlU')0Y  
catch(IOException e){e.printStackTrace ();} ->Z9j(JU  
catch(Exception e){e.printStackTrace ();} 1Vf?Rw  
} v C23  
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//读取保存的下载信息（文件指针位置） 7bV(eV  
private void read_nPos() @jL](Mq|]  
{ ~7p!t%;$  
try{ DWv(|gO  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ak,KHA6u  
int nCount = input.readInt(); %x'}aTa  
nStartPos = new long[nCount]; e p jb  
nEndPos = new long[nCount]; 7eNLs  
for(int i=0;i<nStartPos.length;i++) mM9aT0_w  
{ [^Z)f<l  
nStartPos = input.readLong(); 2[!3!@.  
nEndPos = input.readLong(); u+/Uc:XK)  
} {c :7:  
input.close(); ]& 8c 45c  
} ~];r{IU  
catch(IOException e){e.printStackTrace ();} 'FNnFm  
catch(Exception e){e.printStackTrace ();} $-D}y:  
} Yg/g9$'  
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private void processErrorCode(int nErrorCode) ^C=dq(i=[  
{ Vc[aNpE  
System.err.println("Error Code : " + nErrorCode); r'
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} jgvzp  
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@V?T'@W7D  
//停止文件下载 Vu`5/QDq  
public void siteStop() 1Clid\T,o  
{ ?rm3Iac0S  
bStop = true; ` 0$i^,}  
for(int i=0;i<nStartPos.length;i++) 8Y]% S9.  
fileSplitterFetch.splitterStop(); qX[{_$^Q  
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} a}e GB +  
} F50l->F2&  
//负责部分文件的抓取 vp32}zeD  
**FileSplitterFetch.java (ZPl~ZO  
*/ 6"Ze%:AZZ  
package NetFox; F9} zt 9  
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import java.io.*; h;+{0a  
import java.net.*; iQJa6QF&:  
#a`D6;  
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public class FileSplitterFetch extends Thread { (*M*muk  
.5"s[(S  
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String sURL; //File URL &SG5f[  
long nStartPos; //File Snippet Start Position >'lvZt  
long nEndPos; //File Snippet End Position xfF;u9$;  
int nThreadID; //Thread's ID tj?%{L  
boolean bDownOver = false; //Downing is over r|63T%q!  
boolean bStop = false; //Stop identical "ejsz&n  
FileAccessI fileAccessI = null; //File Access interface )3 I~6ar  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +CVB[r#hu  
{ M}! qH.W  
this.sURL = sURL; n^q%_60H  
this.nStartPos = nStart; qyBC1an5,  
this.nEndPos = nEnd; 'fs tfk  
nThreadID = id; %[4u #G`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位  >akC  
} ur:8`+" (  
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public void run() fN1b+d~*6  
{ }4g$aTc  
while(nStartPos < nEndPos && !bStop) R XCjYzt  
{ QuP)j1"X  
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}rvX}   
try{ ]K3bDU~  
URL url = new URL(sURL); YQ@2p?4m  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); N%,zME  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~_hA{$  
String sProperty = "bytes="+nStartPos+"-"; 8(Q|
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httpConnection.setRequestProperty("RANGE",sProperty); c1q;  
Utility.log(sProperty); .VR~[aD  
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InputStream input = httpConnection.getInputStream(); f
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//logResponseHead(httpConnection); QE8`nMf  
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byte[] b = new byte[1024]; aNn4j_V(  
int nRead; UGlHe7  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 76o3Sge:  
{ 7|o!v);uR  
nStartPos += fileAccessI.write(b,0,nRead); k*u6'IKi.4  
//if(nThreadID == 1) \#PZZ
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YV _ 7 .+A  
} &"?99E>  
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Utility.log("Thread " + nThreadID + " is over!"); qqJghV$Oj  
bDownOver = true; M}j[{wW3  
//nPos = fileAccessI.write (b,0,nRead); JljCI@  
} 2">de/jS  
catch(Exception e){e.printStackTrace ();} `rXb:P7m{j  
} t 9t '9  
} !MrQ-B(  
:.tL~% q  
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//打印回应的头信息 @U4hq7xzV2  
public void logResponseHead(HttpURLConnection con) x#5vdBf  
{ h-//v~V)  
for(int i=1;;i++) uts>4r>+  
{ H0!$aO  
String header=con.getHeaderFieldKey(i); 2~4&4  
if(header!=null) ::+;PRy_E  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); DSRmFxkk  
Utility.log(header+" : "+con.getHeaderField(header)); f`KO#Wc  
else d``wx}#Uk  
break; tot~\S  
} 6uv~.-T<l  
} z(8G=C  
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public void splitterStop() mo3A*|U  
{ "G-h8IN^O  
bStop = true; :5['V#(o  
} u;]xAr1  
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} ;Xa N  
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/* &XdTY +  
**FileAccess.java Q-!gO  
*//文件访问(定位，写) hkyO_ns  
package NetFox; 9J~\.:jH-  
import java.io.*; j:qexhtho  
^%!SKhRIK  
c_C
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public class FileAccessI implements Serializable{ \m~p;B  
*sZH3:  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6-uLK'E  
RandomAccessFile oSavedFile; -%]1q#C>@  
long nPos; rQ_]%ies8  
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public FileAccessI() throws IOException /M::x+/T  
{ w[\rS`J  
this("",0); #
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} |:&O!36  
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public FileAccessI(String sName,long nPos) throws IOException Ue60Mf
  
{ ;2\6U;  
oSavedFile = new RandomAccessFile(sName,"rw"); W8$0y2  
this.nPos = nPos; 122s7A  
oSavedFile.seek(nPos); dCS f$5  
} ~,ozhj0f/  
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public synchronized int write(byte[] b,int nStart,int nLen) ;9WU
t,R  
{ G'p322Bu  
int n = -1; ^e <E/j{~  
try{ .4U*.Rf  
oSavedFile.write(b,nStart,nLen); @MB)B5  
n = nLen; 09anQHa  
} !H)-  
catch(IOException e) fqY'Uq$=  
{ 'Etq;^H  
e.printStackTrace (); ,OubK
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} !`RMXUV  
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kE
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return n; "f_qG2A{  
} ^g|cRI_"  
}.&;NgZS  
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} t"YsIOT:O"  
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/* <=&$+3r  
**SiteInfoBean.java _p%n%Oce
 
*/ d?J&mLQ6  
package NetFox; q)Nw$dW<  
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public class SiteInfoBean { ^}p##7t[  
M @-:iP  
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private String sSiteURL; //Site's URL (@5`beEd  
private String sFilePath; //Saved File's Path sAqy(oy#M  
private String sFileName; //Saved File's Name tx>7?e8E  
private int nSplitter; //Count of Splited Downloading File K&`1{,  
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nL/]
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public SiteInfoBean() 1J/'R37lP  
{//nSplitter的缺省值为5 $8UW^#Bpq  
//default value of nSplitter is 5 kt)Et  
this("","","",5); +sjzT[ Dn  
} A2:}bb~H  
}URdoTOvb  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #8"oqqYi  
{ X1`3KqK<9  
sSiteURL= sURL; gh?[x.U  
sFilePath = sPath; o4WQA"VxM  
sFileName = sName; Fy Ih\  
this.nSplitter = nSpiltter; J'|=J   
 jb&MC2  
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} A8vd@0  
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public String getSSiteURL() pN5kcvQ  
{ HS{Vohy>  
return sSiteURL; N=<`|I  
} CL1*pL  
|*NZ^6`@  
)/>BgXwH  
public void setSSiteURL(String value) [M~tH *4"  
{ O%\cRn8m  
sSiteURL = value; zvdut ,6<  
} 4-x<^ ev=  
MVzuE}  
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public String getSFilePath() GT<oYrjU  
{ <z,)4z++  
return sFilePath; 8A3/@Z;0S  
} #\l
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public void setSFilePath(String value) A|r3c?q  
{ ]<\YEz&A  
sFilePath = value; Tt)z[^)%  
} 0<\|D^m=&h  
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public String getSFileName() bKCE;Wu:G  
{ ;F"!$Z/  
return sFileName; ,7&\jET5^0  
} I!Z`'1"  
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public void setSFileName(String value) K/ On|C  
{ !\7`I}:  
sFileName = value; xyGwYv>*KO  
} wg?}c ;  
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$3HqVqF^R  
public int getNSplitter()  *XhlIQ  
{ =){G  
return nSplitter; uxU-N  
} cWkg.ri-x  
1WMZ$vsQUb  
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public void setNSplitter(int nCount) M co:eE  
{ }MRgNr'k  
nSplitter = nCount; _ l`F}v  
} larv6ncV  
} D
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/* Zt3sU_  
**Utility.java a|u#w~  
*/ ZTzec zXpQ  
package NetFox; 9<_hb1'  
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public class Utility { 3<r7"/5  
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;\0|1Eem`  
public Utility() lz0-5z+\  
{ , lR(5ZI  
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} hH1Q:}a  
_s^tL2Pc  
//线程睡眠 h.vy SwF"j  
public static void sleep(int nSecond) uy<3B>3~.  
{ utZI'5i  
try{ M
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Thread.sleep(nSecond); V|'@D#\  
} "mJo<i}  
catch(Exception e) lubsLI  
{ #EzhtuHxn  
e.printStackTrace (); %]LoR$|Y  
} L>14=Pr^(  
} e`4mrBtz|  
S5hc@^|0Z  
//日志 }h;Z_XF&  
public static void log(String sMsg) -w"I  
{ QlGK+I>y;  
System.err.println(sMsg); FvT4?7-  
} kc2B_+Y1  
4~Cf_`X}]  
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public static void log(int sMsg) Gky*EY  
{ m-O*t$6  
System.err.println(sMsg); F7=9> ,  
} gV@xu)l  
} aftt^h  
*,X)tZ6VX  
RDbNC v#  
/* AJ/Hw>>$?m  
**TestMethod.java rd->@s|4mT  
*/ %h ;oi/pe  
package NetFox; q<E7qY+  
n8EKTuy  
.$-;`&0cZ  
public class TestMethod { Lmjd,t  
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PJB_"?NTTC  
public TestMethod() =r/K#hOR\J  
{ ///xx/weblogic60b2_win.exe )$^xbC#j`3  
try{ Mt4]\pMUb  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); qY-aR;  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); IA0vSF:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); AIOGa<^  
fileFetch.start(); l#cVQ_^"  
} s>G6/TTH6  
catch(Exception e){e.printStackTrace ();} 65zwi-  
? /!Fv/  
dwB#k$VIOw  
} "#wAGlH6>  
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?3N/
#  
public static void main(String[] args) \Nik`v*Pd  
{ `P\H{  
new TestMethod(); ~W>{Dd(J_  
} G--vwvL  
} ypM,i  
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