http断点续传简单实现（java)

/* ?Ss!e$jf  
**SiteFileFetch.java \lNN Msd&  
*/ v(%*b,^  
package NetFox; -H-~;EzU  
import java.io.*; /_ajaz%  
import java.net.*; K"@M,8hb  
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public class SiteFileFetch extends Thread { f`66h M[  
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SiteInfoBean siteInfoBean = null; //文件信息Bean mXs; b 2r^  
long[] nStartPos; //开始位置 Mrb)  
long[] nEndPos; //结束位置 ,"79P/C  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 l}M!8:UzU  
long nFileLength; //文件长度 1yY0dOoLG)  
boolean bFirst = true; //是否第一次取文件 Srd4))2/0  
boolean bStop = false; //停止标志 dUdT7ixo  
File tmpFile; //文件下载的临时信息 _PR4`C*  
DataOutputStream output; //输出到文件的输出流 )Xyn q(  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @`Su0W+.  
public SiteFileFetch(SiteInfoBean bean) throws IOException % %UE+u@J  
{ Y\'}a+:@Ph  
siteInfoBean = bean; +x}<IS8  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); %e}Saf  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); bi;1s'Y<D  
if(tmpFile.exists ()) g< .qUBPKX  
{ vY`s'%WV  
bFirst = false; Ny)X+2Ae  
read_nPos(); uFga~&#g  
} #gw]'&{8D  
else ]')RMg zM*  
{ "@

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nStartPos = new long[bean.getNSplitter()]; [z9Z5sLO  
nEndPos = new long[bean.getNSplitter()]; '@P^0+B!(.  
} KJZ4AWH`  
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} ;i+#fQO7Q  
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public void run() aC)!T  
{ ^5 Tqy(M  
//获得文件长度 x]ot 2  
//分割文件 X)3!_  
//实例FileSplitterFetch }*"p?L^p{  
//启动FileSplitterFetch线程 ;gr9/Vl  
//等待子线程返回
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try{ uY'
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if(bFirst) ^K@C"j?M/  
{ H} g{Cr"Ex  
nFileLength = getFileSize(); BIL Lq8)  
if(nFileLength == -1) jWfa;&Ra  
{ u\JNr}bL  
System.err.println("File Length is not known!"); +=8VTCn?  
} FaJ&GOM,  
else if(nFileLength == -2) M
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{ E-g_".agO  
System.err.println("File is not access!"); k|d+#u[Mj@  
} jRV/A!4  
else wLr_-vJ  
{ q>
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for(int i=0;i<nStartPos.length;i++) V3j= Kf  
{ 8)I^ t81
 
nStartPos = (long)(i*(nFileLength/nStartPos.length)); H$4:lH&(  
} @f_+=}|dc  
for(int i=0;i<nEndPos.length-1;i++) [!OxZ!  
{ |ZBI *  
nEndPos = nStartPos[i+1]; #Mw8^FST  
} "snw4if  
nEndPos[nEndPos.length-1] = nFileLength; W5MTD]J   
} Q]>.b%s[  
} 1
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//启动子线程 czd~8WgOa  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Th%Sjgsn
 
for(int i=0;i<nStartPos.length;i++) y'*K|aTG  
{ -3Vx76Y  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4{`{WI{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), '!$Rw"K.  
nStartPos,nEndPos,i); c!9nnTap  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V "h +L7T  
fileSplitterFetch.start(); o"#\ >  
}
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [ibu/W$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); D,FkB"ZZE  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", BThrO d  
nEndPos = " + nFileLength); ?5 7Sk+  
// fileSplitterFetch[nPos.length-1].start();
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//等待子线程结束 8-77d^cprR  
//int count = 0; @sC`!Rmy'-  
//是否结束while循环 kPLxEwl  
boolean breakWhile = false; W6/yn
 
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while(!bStop) @I!0-OjL  
{ )Z9>$V$j  
write_nPos(); d-dEQKI?;  
Utility.sleep(500); N<injx  
breakWhile = true; e**qF=HCw  
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for(int i=0;i<nStartPos.length;i++) &KRX[2  
{ ~IN>3\j  
if(!fileSplitterFetch.bDownOver) 6~w@PRy  
{ :Fvrs( x  
breakWhile = false; hQDXlFHT  
break; r\V ={p  
} OpYY{f  
} AkQ~k0i}b  
if(breakWhile) kpN)zxfk  
break; %OOl'o"V{s  
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j#q-^
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//count++; N[ Og43Y  
//if(count>4) A2jUmK.&  
// siteStop(); q5)O%l!  
} fmDCPkj  
}S<2A7)el  
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System.err.println("文件下载结束！"); '$%l7  
} 4@# `t5H  
catch(Exception e){e.printStackTrace ();} ._{H~R|  
} @r/nF5  
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//获得文件长度 2a Q[zK  
public long getFileSize() 8c^TT&  
{ XuM'_FN`A<  
int nFileLength = -1; :E )>\&  
try{ 9m~p0ILh  
URL url = new URL(siteInfoBean.getSSiteURL()); ;@Y;g(bw:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4u})+2W  
httpConnection.setRequestProperty("User-Agent","NetFox"); n8ZZ#}Nhg  
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int responseCode=httpConnection.getResponseCode(); q6V>zi  
if(responseCode>=400) QX'qyojxN  
{ n[Y~]  
processErrorCode(responseCode); Fyatd  
return -2; //-2 represent access is error IKilr'  
} 6zuTQ^pz  
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String sHeader; D7Q$R:6|  
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for(int i=1;;i++) z/@slT  
{ 9Y_HyOZ*GX  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A@{PZ   
//Utility.log(in.readLine()); PP33i@G  
sHeader=httpConnection.getHeaderFieldKey(i); @YTaSz$L  
if(sHeader!=null) a'yK~;+_9  
{ ML56k~"BL  
if(sHeader.equals("Content-Length")) VY=jc~c]v  
{ h^(*Tv-!  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _H7x9 y=  
break; #( 146  
} |~mOfuQb  
} ra gXn  
else O`t&ldU  
break; fdi\
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} p}pjfG  
} eF-."1  
catch(IOException e){e.printStackTrace ();} !9VY|&fHe  
catch(Exception e){e.printStackTrace ();} .~~T\rmI  
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Utility.log(nFileLength); m'=Crei  
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return nFileLength; ,G?WAOy,  
} lE(HFal0-(  
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//保存下载信息（文件指针位置） bI9~jWgGp  
private void write_nPos() TpwkD_fg  
{ 
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try{ jZkcBIK2  
output = new DataOutputStream(new FileOutputStream(tmpFile)); aP
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output.writeInt(nStartPos.length); Q1I6$8:7  
for(int i=0;i<nStartPos.length;i++) %axh`xK#  
{ U}rU~3N  
// output.writeLong(nPos); \aUC(K~o\;  
output.writeLong(fileSplitterFetch.nStartPos); V1`o%;j  
output.writeLong(fileSplitterFetch.nEndPos); w(3G&11N?  
} K+K#+RBK  
output.close(); u$Jz~:=,  
} .|>3k'<l  
catch(IOException e){e.printStackTrace ();} ep)n_!$OH"  
catch(Exception e){e.printStackTrace ();} )e=D(qd  
} Em
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' ;FnIZ  
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//读取保存的下载信息（文件指针位置） Kaqc74Mv  
private void read_nPos() Vl=l?A8  
{ J7Hl\Q[D1  
try{ bP$dU,@p~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); rCbDu&k]  
int nCount = input.readInt(); SaAFz&WRl  
nStartPos = new long[nCount]; Q}K"24`=  
nEndPos = new long[nCount]; 3-qr)h  
for(int i=0;i<nStartPos.length;i++) DIfaVo/"  
{
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nStartPos = input.readLong(); v,{ :Ez(H  
nEndPos = input.readLong(); y@:h4u"3  
} 17[3/m8a  
input.close(); u=?.}Pj  
} 8f)
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catch(IOException e){e.printStackTrace ();} P%:wAYz1^O  
catch(Exception e){e.printStackTrace ();} ~"&|W'he[  
} vkx7paY_  
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private void processErrorCode(int nErrorCode) *yt=_Q  
{ FxtQXu-g  
System.err.println("Error Code : " + nErrorCode); F|o:W75  
} j_!F*yul  
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//停止文件下载 jrlVvzZ  
public void siteStop() ~Ei$nV  
{ ^& t
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bStop = true; 9N%We|L,c  
for(int i=0;i<nStartPos.length;i++) n.`($yR_  
fileSplitterFetch.splitterStop(); 6xe*E[#k\  
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} ?qLFaFt/  
} Yq0| J  
//负责部分文件的抓取 q77;ZPfs8  
**FileSplitterFetch.java jk; clwyz/  
*/ B:;pvW]  
package NetFox; 8>2.UrC  
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import java.io.*; 'RQ+g}|Ba!  
import java.net.*; [LjT*bi  
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public class FileSplitterFetch extends Thread { szZr4y<8|1  
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String sURL; //File URL hLd^ agX  
long nStartPos; //File Snippet Start Position '8RsN-w  
long nEndPos; //File Snippet End Position zUkgG61  
int nThreadID; //Thread's ID F#,90F'  
boolean bDownOver = false; //Downing is over 55nlg>j  
boolean bStop = false; //Stop identical UUYSFa%  
FileAccessI fileAccessI = null; //File Access interface g|DF[  
=w_Ype`  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException t9kzw*U9  
{ ';w#w<yaI  
this.sURL = sURL; 7u -p%eq2  
this.nStartPos = nStart; Z58X5"  
this.nEndPos = nEnd; (Ft+uuG  
nThreadID = id; jiV<+T?  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Zw 26  
} IXMop7~  
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public void run() knu,"<  
{ =V,mtT  
while(nStartPos < nEndPos && !bStop) vsCCB}7\  
{ qOIyub  
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try{ P%V'4pc  
URL url = new URL(sURL); k_L7 kvpt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); fa jGZyd0:  
httpConnection.setRequestProperty("User-Agent","NetFox"); |B?m,U$A!  
String sProperty = "bytes="+nStartPos+"-"; X:f UI4  
httpConnection.setRequestProperty("RANGE",sProperty); fy>{QC\  
Utility.log(sProperty);
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InputStream input = httpConnection.getInputStream(); %~O,zs.2p  
//logResponseHead(httpConnection); e
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byte[] b = new byte[1024]; |IeTqEu9  
int nRead; 7Kr*P<-G  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {g'(~ qv  
{ c?(4t67|  
nStartPos += fileAccessI.write(b,0,nRead); vONasD9At  
//if(nThreadID == 1) p,EQ#Ik  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9%o32eo,3  
} +xh`Q=A  
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Utility.log("Thread " + nThreadID + " is over!"); xeg/
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bDownOver = true; )nC]5MXU  
//nPos = fileAccessI.write (b,0,nRead); lZd(emH@  
} 7cuE7"  
catch(Exception e){e.printStackTrace ();} WA<v9#m  
} \#8D>i?m  
} AVsDt2A  
euK5pA>L  
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//打印回应的头信息 b<tNk]7  
public void logResponseHead(HttpURLConnection con) >2Y=*K,:  
{ ]{;gw<T  
for(int i=1;;i++) $g^@AdE%  
{ aj-Km`5r}  
String header=con.getHeaderFieldKey(i); 6B8VfQ9[  
if(header!=null) z 4e7PW|  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); =Pyj%4Rs  
Utility.log(header+" : "+con.getHeaderField(header)); $f$SNx)),  
else |QF7 uV  
break; nQF(vTDN  
} %e8@*~h@  
} ]vB$~3||  
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public void splitterStop() @JiLgIe`  
{ 0.Q Ujw  
bStop = true; %HhBt5w  
} ,5P0S0*{  
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} B5,N7z34F  
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/* [>vLf2OID  
**FileAccess.java v1#otrf  
*//文件访问(定位，写) ,X?{07gH  
package NetFox; h,(26 y/s  
import java.io.*; CmWeY$Jb  
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public class FileAccessI implements Serializable{ w$>u b@=  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 %6t
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RandomAccessFile oSavedFile; av(6wht8  
long nPos; 3RUy,s  
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public FileAccessI() throws IOException 8%:Iv(UMk  
{ 2/U.|*mH  
this("",0); qRu~$K  
} b;L\EB  
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public FileAccessI(String sName,long nPos) throws IOException A_rGt?i  
{ i[i4h"$0  
oSavedFile = new RandomAccessFile(sName,"rw"); I !- U'{  
this.nPos = nPos; 1Te%F+7  
oSavedFile.seek(nPos); !OZy7  
} "6A `
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{aZ0;  
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public synchronized int write(byte[] b,int nStart,int nLen) IM*y|UHt  
{ g/4
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int n = -1; (xycJ`N  
try{ ?C]vS_jAh  
oSavedFile.write(b,nStart,nLen); 6dHOf,zjm  
n = nLen; z,RhYm  
} ]iVcog"T  
catch(IOException e) 2y75  
{ xexaQuK  
e.printStackTrace (); )',R[|<  
} {.`vs;U  
53_Hl]#qZ  
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return n; SV4E0c>  
} p;a,#IJu  
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} $yP*jO4i  
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/* ,};&tR  
**SiteInfoBean.java 'I|v[G$l
 
*/ j\yjc/m  
package NetFox; 0J*??g-n  
'(6z. toQ  
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public class SiteInfoBean { I]|Pq  
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private String sSiteURL; //Site's URL 'B$
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private String sFilePath; //Saved File's Path &/Z /Y ]  
private String sFileName; //Saved File's Name J[&@PUy  
private int nSplitter; //Count of Splited Downloading File 5"VTK  
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public SiteInfoBean() wKh4|Ka  
{//nSplitter的缺省值为5 hwuiu*  
//default value of nSplitter is 5 ]Ee?6]bN  
this("","","",5); E#34Wh2z  
}
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]2A^1Del  
{ ;7*[Bcj.  
sSiteURL= sURL; >fG3K`  
sFilePath = sPath; 6{K,c@VFd  
sFileName = sName; _`$qBw.Nx  
this.nSplitter = nSpiltter; U)TUOwF  
299H$$WS,Z  
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} b1q"!+8y  
j8i[ONq^  
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public String getSSiteURL() te`$%NRl  
{ W ~<^L\Lu  
return sSiteURL; u~N?NW Q  
} iO$8:mxm0?  
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public void setSSiteURL(String value) sfH_5 #w  
{ 5&g@3j]  
sSiteURL = value; Oamg]ST  
} wVXS%4|v  
&<g|gsG`  
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public String getSFilePath() Rr$-tYy6  
{ Oxnp0 s  
return sFilePath; `cn#B BV  
} 2ACCh4(/P  
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public void setSFilePath(String value) &3>)qul  
{ m,28u3@r  
sFilePath = value; cU (D{~  
} Y|m+dT6  
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public String getSFileName()
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{ h8j.(  
return sFileName; yF:1( 4  
} 0JS?;fk  
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Rh2+=N<X  
public void setSFileName(String value) OKZV{Gja  
{ 234p9A@  
sFileName = value; o 11jca|  
} Xq4O@V  
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j  
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public int getNSplitter() &AMl:@p9  
{ ^6
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return nSplitter; Hvauyx5T  
} ^0)g/`H^>  
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public void setNSplitter(int nCount) FkDmP`Od  
{ %Xd[(Q)  
nSplitter = nCount; 5ta `%R_  
} 4B;=kL_f  
} %Xg4b6<9  
#Pau\|e_  
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/* 5~U/  
**Utility.java 2W(s(-hD  
*/ I|!OY`ko  
package NetFox; hag$GX'2k
 
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public class Utility { o[4}h:> dq  
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public Utility() 0o4XUW   
{ k'Hs}zeNn  
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} *R,5h2;  
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//线程睡眠 ?<,l3pwqa  
public static void sleep(int nSecond) A2FYBM`Q&D  
{ }K>d+6qk5  
try{ \K{ z  
Thread.sleep(nSecond); iMh#TUlQEQ  
} tjS@meT  
catch(Exception e) i"FtcP^  
{ zk+9'r`-D  
e.printStackTrace (); P;no?  
} 2;b\9R^>A  
} S?LQu  
2.y-48Nz  
//日志 dQX6(Jj  
public static void log(String sMsg) :=V[7n])  
{ nF:4}qy\  
System.err.println(sMsg); 4@gG<QJW  
} U>SShpmZA  
T Z@]:e:"b  
7z,C}-q  
public static void log(int sMsg) (E3b\lST  
{ `[yKFa I  
System.err.println(sMsg); #z%fx
 
} fbvL7* (  
} /s?`&1v|r  
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/* ^ +\dz  
**TestMethod.java #%2rP'He  
*/ W*:.Gxv]  
package NetFox; 6_;icpN]  
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h"W,WxL8  
public class TestMethod { `(;m?<%  
/}Axf"OE  
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public TestMethod() Rv>-4@fMJ  
{ ///xx/weblogic60b2_win.exe Q{>k1$fkV  
try{ Yh7t"=o  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); R29~~IOqO  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); C): 1?@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Nx;~@  
fileFetch.start(); ~8+ Zs
  
} @ q3k%$4  
catch(Exception e){e.printStackTrace ();} +`0k Fbx  
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} q i;1L Kc  
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public static void main(String[] args) ~ Iuf}D;  
{ h#*dI`>l-  
new TestMethod(); S hWJ72c  
} ^76]0`gS  
} e9tjw[+A  
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