http断点续传简单实现（java)

/* C)UU/4a;  
**SiteFileFetch.java D
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*/ 6\.LG4@LO  
package NetFox; \'|t>|zhp  
import java.io.*; Vi
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import java.net.*; ikb77?.  
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public class SiteFileFetch extends Thread { tCA0H\';  
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SiteInfoBean siteInfoBean = null; //文件信息Bean s0Z)BR #  
long[] nStartPos; //开始位置 P
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long[] nEndPos; //结束位置 'MNCJ;A@V  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 g`tV^b")  
long nFileLength; //文件长度 "D KrQ,L  
boolean bFirst = true; //是否第一次取文件 Md8<IFi9]Q  
boolean bStop = false; //停止标志 @xBO[v  
File tmpFile; //文件下载的临时信息 <Q`3;ca^  
DataOutputStream output; //输出到文件的输出流 [$:L|V!{  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） /s+S\ djk  
public SiteFileFetch(SiteInfoBean bean) throws IOException @gM}&G08  
{ xVN!w\0  
siteInfoBean = bean; 3Wx\Liw,  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); C@<gCMj,"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #7}YSfm^6  
if(tmpFile.exists ())
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{ F[W0gjUc  
bFirst = false; 8!@}\6qM  
read_nPos(); *O\lR-z!k  
} SUW=-M  
else A>HCX 4i  
{ 7W5Cm\  
nStartPos = new long[bean.getNSplitter()]; 3-kL0Q["  
nEndPos = new long[bean.getNSplitter()]; sYvlf0  
} vo2GFo  
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} ?{5}3abB`  
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public void run() u,N<U t  
{ ]1W]  
//获得文件长度 "<%J^Z9G  
//分割文件 8#o2qQ2+  
//实例FileSplitterFetch \w(0k^<7  
//启动FileSplitterFetch线程 ;qr?[{G  
//等待子线程返回 */K]sQZa  
try{ v"o@q2f_  
if(bFirst) 3preBs#i  
{ BMV\@Sg  
nFileLength = getFileSize(); |sP0z !)b  
if(nFileLength == -1) U;"J8  
{  C?'s  
System.err.println("File Length is not known!"); s<aG
 
} ]9JH.fF  
else if(nFileLength == -2)  !$!%era`  
{ o)DO[  
System.err.println("File is not access!"); V7O7"Q^q  
} :Gx5vo  
else n[# **s  
{ 7VWy1  
for(int i=0;i<nStartPos.length;i++) ra_v+HR7  
{ j'hWhLax  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); I:YgK
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} J8Vzf$t};  
for(int i=0;i<nEndPos.length-1;i++)  acQHqR  
{ *Tr{a_{~C  
nEndPos = nStartPos[i+1]; 8F's9c,  
} } j;es(~D  
nEndPos[nEndPos.length-1] = nFileLength; EQ|Wke  
} L.}sN.  
} "*(a2k3J  
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//启动子线程 UISsiiG(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; up0=Y o@  
for(int i=0;i<nStartPos.length;i++) v$g\]QS p  
{
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Fdq5:v?k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !C^>
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nStartPos,nEndPos,i); IR;3{o  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *&R|0I{>  
fileSplitterFetch.start(); x-4d VKE*z  
} v$5D&Tv  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), vz1I/IdTd  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #TH(:I=[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", .C ,dV7  
nEndPos = " + nFileLength); Ae"|a_>fMI  
// fileSplitterFetch[nPos.length-1].start(); #uICHt3  
JeA_mtSQ|  
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//等待子线程结束 3*(><<ZC  
//int count = 0; yx;K&>  
//是否结束while循环 +kD JZ  
boolean breakWhile = false; S;%k?O7v  
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while(!bStop) R|wS*xd,  
{ xj3{Ke`6  
write_nPos(); FT J{  
Utility.sleep(500); p1mAoVxR  
breakWhile = true; k72NXagh  
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for(int i=0;i<nStartPos.length;i++) [~`p~@\+  
{ P4|A\|t  
if(!fileSplitterFetch.bDownOver) RUVrX`u*(  
{ <p2\;\?4z  
breakWhile = false; l7IF9b$c  
break; MIWc @.i2  
} >xsY"N&1i'  
} A* Pz-z>z  
if(breakWhile) NGO?K?  
break; 8qxZ7|Y@  
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//count++; Py/~Q-8p  
//if(count>4) 8=?U7aw  
// siteStop(); "I{Lcn~!@  
} j7NOYm5N  
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System.err.println("文件下载结束！"); <JvYCWX`  
} cjd-B:l  
catch(Exception e){e.printStackTrace ();} S?VKzVDB.S  
} 7-\wr^ll3  
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//获得文件长度 Vh]=sd<F  
public long getFileSize() <yvo<R^30  
{ B[+b%a3  
int nFileLength = -1; u^WZsW  
try{ _x,(576~  
URL url = new URL(siteInfoBean.getSSiteURL()); /ZH*
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C 20VSwd  
httpConnection.setRequestProperty("User-Agent","NetFox");
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int responseCode=httpConnection.getResponseCode(); 4E1j0ARQQ  
if(responseCode>=400) F5M|QX@
-  
{ 9F~5Ht  
processErrorCode(responseCode); dP]Z:  
return -2; //-2 represent access is error !X-
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} eiRVw5g  
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String sHeader; SbsdunW+?  
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for(int i=1;;i++) EZhk(LE  
{ mGoC8t}iP  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());
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//Utility.log(in.readLine()); yD8Qy+6L  
sHeader=httpConnection.getHeaderFieldKey(i); \{ C ~B;=  
if(sHeader!=null) q^<;B Y  
{ :R$v7{1  
if(sHeader.equals("Content-Length")) MiF( &#  
{ '
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); N4{g[[ T  
break; -Y N(j\  
} !vHCftKel  
} Hd gABIuX  
else &?}h)
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break; wOrj-Smx  
} %?8.UW\m  
} fWDTP|DV  
catch(IOException e){e.printStackTrace ();} zgn`@y2  
catch(Exception e){e.printStackTrace ();} <7/7+_y  
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Utility.log(nFileLength); _eH@G(W(  
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return nFileLength; l}#d^S/  
}
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//保存下载信息（文件指针位置） fQ_tXY  
private void write_nPos() -Q ];o~  
{ T~p>Ed9  
try{ NvpDi&i  
output = new DataOutputStream(new FileOutputStream(tmpFile)); OG
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output.writeInt(nStartPos.length); 1 7iw`@  
for(int i=0;i<nStartPos.length;i++) Y'R/|:YL@  
{ +j$nbU0U  
// output.writeLong(nPos); k9VWyq__  
output.writeLong(fileSplitterFetch.nStartPos); |>>^Mol  
output.writeLong(fileSplitterFetch.nEndPos); ^nQJo"g\  
} %0f*OC  
output.close(); uF)^mT0D=  
} ``kesz  
catch(IOException e){e.printStackTrace ();} :cP u  
catch(Exception e){e.printStackTrace ();} Dr}elR>~G=  
} SLvo)`Nc3-  
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X[?E{[@Z  
//读取保存的下载信息（文件指针位置） [:A">eYI  
private void read_nPos() 2%`8  
{ 8Kn}o@Yd  
try{ ICTjUQP  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); N2u4MI2  
int nCount = input.readInt(); $ylxl"Y  
nStartPos = new long[nCount]; NxF
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nEndPos = new long[nCount];  FE1En  
for(int i=0;i<nStartPos.length;i++) v)*eLX$  
{ a"k,x-EL(  
nStartPos = input.readLong(); Ct3+ga$  
nEndPos = input.readLong(); "#Q"gC.K  
} u=(.}  
input.close(); 4%<D\#  
} nGTqW/k[+s  
catch(IOException e){e.printStackTrace ();} Fg2/rC:_  
catch(Exception e){e.printStackTrace ();} cn9=wm\\  
} E6-~  
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private void processErrorCode(int nErrorCode) +>%AG&Pc  
{ 'sk M$jr  
System.err.println("Error Code : " + nErrorCode); li}>xDSQ4  
} ZalL}?E ?  
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//停止文件下载 \PmM856=ms  
public void siteStop() H;FzWcm  
{ P1`YbLER5  
bStop = true; QX.U:p5C  
for(int i=0;i<nStartPos.length;i++) eNm Wul  
fileSplitterFetch.splitterStop(); KXu1%`x=%Z  
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} =]<X6!0mR  
} u:^9ZQ+  
//负责部分文件的抓取 ^)3=WD'!  
**FileSplitterFetch.java ,^@/I:  
*/ XKT[8o<L  
package NetFox; \@_?mL@=  
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import java.io.*;
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import java.net.*; fs#9*<]m  
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public class FileSplitterFetch extends Thread { m`@~ZIa?>B  
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String sURL; //File URL SQJ4}w>i  
long nStartPos; //File Snippet Start Position #*}cc  
long nEndPos; //File Snippet End Position rFto1m  
int nThreadID; //Thread's ID miY=xwK&  
boolean bDownOver = false; //Downing is over EDA6b]  
boolean bStop = false; //Stop identical  b|Eo\l2  
FileAccessI fileAccessI = null; //File Access interface 3E8 Gh>J_  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException uN$ <7KB"  
{ qp/nWGj  
this.sURL = sURL; P_ b8_ydU  
this.nStartPos = nStart; 6N.MCB^  
this.nEndPos = nEnd; 3gW+|3E  
nThreadID = id; -TyBb]  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {ka={7  
} m;u:_4  
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public void run() ~A*$+c(  
{ Z&GjG6t  
while(nStartPos < nEndPos && !bStop) hOm0ND?;1  
{ YUlH5rO3  
v=YI%{tx)  
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try{ z+Ej`$E{lD  
URL url = new URL(sURL); {=P}c:iW  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); HB}iT1.`  
httpConnection.setRequestProperty("User-Agent","NetFox"); Pm|S>r  
String sProperty = "bytes="+nStartPos+"-"; NF_[q(k'  
httpConnection.setRequestProperty("RANGE",sProperty); v&"sTcS|  
Utility.log(sProperty); Qmj%otSg  
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InputStream input = httpConnection.getInputStream(); Kr%O}<"  
//logResponseHead(httpConnection); VQ4rEO=t  
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byte[] b = new byte[1024]; F\+!\b*lP  
int nRead; ov'C0e+o  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) a &hj|  
{ #:[CF:  
nStartPos += fileAccessI.write(b,0,nRead); 9:*a9xT,  
//if(nThreadID == 1) 12bztlv  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); HgOrrewj  
} N<aMUVm  
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Utility.log("Thread " + nThreadID + " is over!"); dca?(B!'6  
bDownOver = true; y~rtYI  
//nPos = fileAccessI.write (b,0,nRead); ?#u_x4==e  
} kBrU%[0O  
catch(Exception e){e.printStackTrace ();} H`jvT]  
} ?L>}( {9  
} >]?!9@#IH  
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//打印回应的头信息 cb_nlG!  
public void logResponseHead(HttpURLConnection con) IjRUL/\=  
{ !l1jQq_mK  
for(int i=1;;i++) - !s=`9o  
{ Y9nyKL  
String header=con.getHeaderFieldKey(i); 3x E^EXV  
if(header!=null) NMhI0Ix$w  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *6]_ 6xO  
Utility.log(header+" : "+con.getHeaderField(header)); @}A3ie'w  
else lFc^y  
break; -
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} 7iH%1f  
} gnZc`)z  
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A
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public void splitterStop() ||rZ
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{ ?xzDz  
bStop = true; NE-c[|rq  
} 42,K

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} jxDA+7  
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 =E:a\r  
/* wL" 2Cm  
**FileAccess.java >Gr,!yP  
*//文件访问(定位，写) RVa{%  
package NetFox; EdS7m,d  
import java.io.*; Hr;\}  
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public class FileAccessI implements Serializable{ Cg%}=  
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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 rJc=&'{&)N  
RandomAccessFile oSavedFile; ?Yh
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long nPos; hbTJXP~~?  
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public FileAccessI() throws IOException Ip;;@o&D  
{ "$N 4S9U  
this("",0); ug9]^p/)^  
} JS0957K  
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public FileAccessI(String sName,long nPos) throws IOException -^= JKd&p  
{ $3{I'r]  
oSavedFile = new RandomAccessFile(sName,"rw"); ,IQ%7*f;O_  
this.nPos = nPos; ^97\TmzP{  
oSavedFile.seek(nPos); e><,WM,e
 
} <~35tOpv  
)r:gDd#/X  
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public synchronized int write(byte[] b,int nStart,int nLen) +We=- e7  
{ hquN+eIDH  
int n = -1; m7m)BX%O  
try{ p
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oSavedFile.write(b,nStart,nLen); q%8Ck)xz  
n = nLen; \Gz 79VW  
} rZG6}<Hx  
catch(IOException e) qwHP8GU  
{ [35>T3Ku  
e.printStackTrace (); 'V(9ein^Q  
} xs$-^FnD  
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return n; t%]b`ad  
} E#mp
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} _&/2-3]\B  
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/* t{Gc,S!]5  
**SiteInfoBean.java \xexl1_;  
*/ _f<#+*y  
package NetFox; OiMr,  
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public class SiteInfoBean { |bv7N@?e  
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private String sSiteURL; //Site's URL nO .:f  
private String sFilePath; //Saved File's Path K.::P84m;  
private String sFileName; //Saved File's Name S]}W+BF3  
private int nSplitter; //Count of Splited Downloading File 38gEto#q  
)dZ1$MC[  
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public SiteInfoBean() jinXK  
{//nSplitter的缺省值为5 .+dego
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//default value of nSplitter is 5 =z +iI;  
this("","","",5);
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} gWHjI3;  
{ ^ @c96&  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) lxXIu8  
{ @[w.!GW%  
sSiteURL= sURL; glgXSOj  
sFilePath = sPath; yu@u0vlc  
sFileName = sName; ,U#FtOec  
this.nSplitter = nSpiltter; spv'r!*\ed  
+]jJ:V  
4+4C0/$Y  
} pJPP6Be<  
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public String getSSiteURL() \:`-"Ou(*  
{ ^U0)iz  
return sSiteURL; OA{PKC  
} d}(b!q9  
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public void setSSiteURL(String value) c-bTf$6}  
{ R:t  
sSiteURL = value; DzE_p- zs  
} wBIhpiJX0  
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-
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public String getSFilePath() ck K9@RQ  
{ V( SRw  
return sFilePath; SH#!Y  
} TM^.y Y  
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public void setSFilePath(String value) &Y|AX2KUC  
{ H|/U0;s  
sFilePath = value; _/)HAw?k  
}  _V_GdQ  
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public String getSFileName() `w/b];e1)  
{ ]sG^a7Z.X  
return sFileName; |^$?9Dn9.L  
} j<C p&}X  
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public void setSFileName(String value) FG6mh,C!  
{ ipn0WQG  
sFileName = value; ,1|0]:  
} u<K{=94!e  
(=/}i'  
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public int getNSplitter() {'1e?  
{ e.?;mD  
return nSplitter; T@\%h8@~]  
} I18<brZJ  
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public void setNSplitter(int nCount) ;}E$>]*Yn  
{ UJhUb)}^  
nSplitter = nCount; 'NDDj0Y  
} 31=vUS  
} _&|<(m&."  
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/* LQ3J$N  
**Utility.java <^Sp4J  
*/ 1@{qPmf^  
package NetFox; (H-}z`sy/@  
~e#QAaXD#5  
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public class Utility {  ua]?D2  
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public Utility() ~#y(]Xec2  
{  V4qv7  
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} w~l%xiC  
?QG?F9?  
//线程睡眠 Zia<$kAO  
public static void sleep(int nSecond) ~5sH`w~vQ  
{ rugR>&mea  
try{ FvT;8ik:3  
Thread.sleep(nSecond); &NB"[Mm:@  
} >[a&,gS  
catch(Exception e) 6
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{ gO
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e.printStackTrace (); /XZ\Yy=  
} Xw |6 #^  
} QDpzIjJj  
q"|#KT^)  
//日志 p{S#>JT
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public static void log(String sMsg) k$v8cE  
{ 6;{E-y  
System.err.println(sMsg); AxZaV;%*  
} d gRTV<vM  
o=ULo &9  
I!;vy/r  
public static void log(int sMsg) YqNI:znm-  
{ 5BsfbLKC  
System.err.println(sMsg); T f;:C]  
} 3}25=%;[  
} Fvae
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1J @43>u{  
:elTqw>pn  
/* kQQhZ8Ch  
**TestMethod.java I4%25=0?  
*/ ]#t5e>o|  
package NetFox; p4M7BK:nf  
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public class TestMethod { WuUT>omH  
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public TestMethod() "pW@[2Dkx/  
{ ///xx/weblogic60b2_win.exe TSHH=`cx  
try{ Z&Ao;=Gp1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); f$p7L.d<  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); T$r?LIa ,Q  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ;/|3U7{c  
fileFetch.start(); IM9P5?kJ ?  
} ~zD*=h2C  
catch(Exception e){e.printStackTrace ();} Zg~6  
#;~dA  
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} 'Bb@K[=s  
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public static void main(String[] args) n9x&Ws;  
{ PHHX)xK  
new TestMethod(); r,-9]?i  
} %5|DdpES  
} rN5;W  
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