http断点续传简单实现（java)

/* 
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**SiteFileFetch.java Y_,Tm  
*/ d]+2rt}]hL  
package NetFox; z6uHe{|  
import java.io.*; ;&`6b:ug  
import java.net.*; PaZd^0'!Z  
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public class SiteFileFetch extends Thread { vEC#W43l  
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SiteInfoBean siteInfoBean = null; //文件信息Bean u]MQ(@HHF  
long[] nStartPos; //开始位置 fir#5,*q|  
long[] nEndPos; //结束位置 St;@ZV  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 SdNxSD$Q  
long nFileLength; //文件长度 RW|Xh8.O  
boolean bFirst = true; //是否第一次取文件 ,)PpE&  
boolean bStop = false; //停止标志 ;uN&yj<}a  
File tmpFile; //文件下载的临时信息 Zy=DY  
DataOutputStream output; //输出到文件的输出流 d:JP935  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ()(^B}VK  
public SiteFileFetch(SiteInfoBean bean) throws IOException 0 LQ%tn  
{ <|1Khygv  
siteInfoBean = bean; L|Bjw3K&D  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); w-P;E!gTt  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); H?wf%0  
if(tmpFile.exists ()) EqF>=5*  
{ :uB(PeAv*  
bFirst = false; Nn-Et
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read_nPos(); DA^!aJ6iF  
} :Ny^-4-N  
else OPJ(ub  
{ ?e2G{0
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nStartPos = new long[bean.getNSplitter()]; \JDxN  
nEndPos = new long[bean.getNSplitter()]; $%.,=~W7  
} L7n
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} %hi]oz  
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public void run() 4P}d/w?'KL  
{ y/;DA=  
//获得文件长度 R#4f_9e<Z  
//分割文件 Mw|lEctN0  
//实例FileSplitterFetch hp$1c  
//启动FileSplitterFetch线程 |>Pz#DCy  
//等待子线程返回 ZDx1v_xr  
try{ 7[:?VXQ  
if(bFirst) l
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{ 'tJxADK  
nFileLength = getFileSize(); Wn&9R j  
if(nFileLength == -1) =kjD ]+l  
{ 3u/ Grs
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System.err.println("File Length is not known!"); N*SUA4bnuM  
} D*t[5,~j  
else if(nFileLength == -2) 58t~? 2E  
{ gdkHaLL"  
System.err.println("File is not access!"); A@jBn6  
} =5
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else 2hY"bpGW  
{ d#|%h] 6  
for(int i=0;i<nStartPos.length;i++) qAi:F=> X  
{ V)]lca  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); CPcB17!  
} X3HJ3F;==  
for(int i=0;i<nEndPos.length-1;i++) J~)JsAXAI  
{ uvJmEBL:  
nEndPos = nStartPos[i+1]; `$XgfMBf |  
} #6mr'e1  
nEndPos[nEndPos.length-1] = nFileLength; ce7$# #f  
} Q}|0  
} 8@r>`c  
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//启动子线程 S^{tRPF%d  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; c3(0BSv  
for(int i=0;i<nStartPos.length;i++) s:oj
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{ &'u%|A@  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ';LsEI[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {EJ+   
nStartPos,nEndPos,i); FTu<$`!1L  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &Z%'xAOGR  
fileSplitterFetch.start(); *1h@Jb34  
} Kl]l[!c7$  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \qJ cs'D  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); # blh9.V&F  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ~h$ H@&5  
nEndPos = " + nFileLength); kH?PEA! \  
// fileSplitterFetch[nPos.length-1].start(); 9Us'Q{CD   
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//等待子线程结束 /4$ c-k  
//int count = 0; 1w#vy1m J  
//是否结束while循环 Y4N)yMSl"  
boolean breakWhile = false; WnhH]WY  
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while(!bStop)
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{ 2{S*$K[M  
write_nPos(); .}Hs'co  
Utility.sleep(500); \zzPsnFIg  
breakWhile = true; p1s|JI  
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for(int i=0;i<nStartPos.length;i++) YGhHIziI  
{ eBqF@'DQ  
if(!fileSplitterFetch.bDownOver) 3935cxT1U  
{ aT8A+=K6  
breakWhile = false; H>wXQ5?W;  
break; D0yH2[j+  
} o<rbC < U  
} !L)yI#i4C  
if(breakWhile) `+(4t4@ew  
break; EUS^Gtc  
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//count++; 4"eeEs h  
//if(count>4) hA+;eXy/  
// siteStop(); :@S=0|:j  
} 02C;  
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System.err.println("文件下载结束！"); L08"8\  
} n6{nx[%7N7  
catch(Exception e){e.printStackTrace ();} 5;A=8bryU  
} ;0}C2Cz'  
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//获得文件长度 4Yd$RP  
public long getFileSize() *oAnG:J+M  
{ (qDJgf4fgn  
int nFileLength = -1; CFeAKjG  
try{ N|w;wF!3  
URL url = new URL(siteInfoBean.getSSiteURL()); Rk}=SB-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wD SSgk  
httpConnection.setRequestProperty("User-Agent","NetFox"); i~tps   
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int responseCode=httpConnection.getResponseCode();
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if(responseCode>=400) 2>im'x 5  
{ 'h 7n}  
processErrorCode(responseCode); cyWDtq  
return -2; //-2 represent access is error kS_37-;  
} Co`:D  
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String sHeader; uN6xOq/  
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for(int i=1;;i++) }t
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{ 7G_OFD  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >2tosxH M  
//Utility.log(in.readLine()); 3,Bm"'b6  
sHeader=httpConnection.getHeaderFieldKey(i); N}q*(r!q<  
if(sHeader!=null) r8!M8Sc  
{ +N!/>w]n  
if(sHeader.equals("Content-Length")) |sDp>..  
{ sJ|IW0Mr  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 7/BA!V(na  
break;  DIh[%  
} @fd
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} F=yE>[! LB  
else ~PCS_  
break; T7Yg^ -"  
} cQ/T:E7$`  
} s=n_(}{ q  
catch(IOException e){e.printStackTrace ();} <@=w4\5j9  
catch(Exception e){e.printStackTrace ();} x2+M0 }g  
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Utility.log(nFileLength); ~T&X#i  
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return nFileLength; zxvowM  
} (rSBzM]H  
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 U66oe3W  
//保存下载信息（文件指针位置） K|.!)L  
private void write_nPos() .,SWa;[iB  
{ \K(# r=  
try{ a4N8zDS  
output = new DataOutputStream(new FileOutputStream(tmpFile)); =eG:Scoug?  
output.writeInt(nStartPos.length); el,n5OZ7  
for(int i=0;i<nStartPos.length;i++) 6}PoBhgSg-  
{ )>
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// output.writeLong(nPos); sg,9{R ^  
output.writeLong(fileSplitterFetch.nStartPos); ,y/N^^\  
output.writeLong(fileSplitterFetch.nEndPos); vC5y]1QDd  
} z#sSLE.$Z  
output.close(); P4~C0z  
} N9cUlrD
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catch(IOException e){e.printStackTrace ();} ^v@& q  
catch(Exception e){e.printStackTrace ();} U+g<lgH1J  
} vjD||!g'  
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//读取保存的下载信息（文件指针位置） sTO9>~sj  
private void read_nPos() (1Ii86EP  
{ !6d`e"\K  
try{ z@J;sz  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); lF!Iu.MM 9  
int nCount = input.readInt(); WhR'MkfL  
nStartPos = new long[nCount]; ca8.8uHY\  
nEndPos = new long[nCount]; pc<A ,?  
for(int i=0;i<nStartPos.length;i++) %ck/ Z  
{ <2 S?QgR,  
nStartPos = input.readLong(); kM/;R)3t4/  
nEndPos = input.readLong(); ;923^*\:F{  
} >zB0+l  
input.close(); b `.h+=3  
} JV9Ft,xk  
catch(IOException e){e.printStackTrace ();} X.!|#FWb+  
catch(Exception e){e.printStackTrace ();} e5fzV.'5  
} $9O%,
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private void processErrorCode(int nErrorCode) L<TL6  
{ _M7NL^B&  
System.err.println("Error Code : " + nErrorCode); wmG[*a_H  
} x$aFJCL  
/|{~GD +A&  
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//停止文件下载 ]Q0+1'yuK  
public void siteStop() p*]nCUs}n  
{ w.\#!@kZ!  
bStop = true; 4vRIJ}nQ  
for(int i=0;i<nStartPos.length;i++) j#E&u*IR  
fileSplitterFetch.splitterStop(); |\ 4cQ  
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} 4PAuEM/z  
} <',bqsg[  
//负责部分文件的抓取 Lj03Mx.2S  
**FileSplitterFetch.java VtD
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*/ Q@/358.LA  
package NetFox; `.a~G y  
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import java.io.*; S?Z"){  
import java.net.*; 5 MD=o7O^  
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public class FileSplitterFetch extends Thread { Vtr5<:eEx  
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String sURL; //File URL (}LLk+  
long nStartPos; //File Snippet Start Position 5Mq7l$]h$  
long nEndPos; //File Snippet End Position zwJVi9sO  
int nThreadID; //Thread's ID x>=8~wIK  
boolean bDownOver = false; //Downing is over gnN"pa!&~  
boolean bStop = false; //Stop identical s4{WPU9  
FileAccessI fileAccessI = null; //File Access interface JgY#W1>  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException r*t\\
2  
{ BTu_$5F  
this.sURL = sURL; <i!7f26r  
this.nStartPos = nStart; CA{(x(W\:  
this.nEndPos = nEnd; COf>H0^%Q  
nThreadID = id; nJ-U*yz  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 x#_0 6  
} [Vaw$c-+[y  
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public void run()  rVo?I  
{ m'i^BE  
while(nStartPos < nEndPos && !bStop) R59'
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{ 52JtEt7E  
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try{ L4L[@tMPmY  
URL url = new URL(sURL); &p2fMVWJ7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !Yan}{A,  
httpConnection.setRequestProperty("User-Agent","NetFox"); =fr_` "?k  
String sProperty = "bytes="+nStartPos+"-"; 1v^eXvY  
httpConnection.setRequestProperty("RANGE",sProperty); \E<t'\>@X  
Utility.log(sProperty); [10;Mg  
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InputStream input = httpConnection.getInputStream();
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//logResponseHead(httpConnection); %"0g}tK6  
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byte[] b = new byte[1024]; z_LN*u  
int nRead; &_N$S2  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {)8!>K%G  
{ ]FLi^}ct  
nStartPos += fileAccessI.write(b,0,nRead); CUR70[pB)  
//if(nThreadID == 1) ?yq1\G)]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .s!qf!{V`  
} eBW=bK~[VP  
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Utility.log("Thread " + nThreadID + " is over!"); hh<Es|v  
bDownOver = true; oJEUNgY&  
//nPos = fileAccessI.write (b,0,nRead); BcvCm+.S:  
} xrPC  
catch(Exception e){e.printStackTrace ();}  qg+bh  
} p7pJ90~E  
} _a 40lcP  
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//打印回应的头信息 5/)
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public void logResponseHead(HttpURLConnection con) FX#fh 2  
{ #AJo75E%  
for(int i=1;;i++) ![,W?  
{ n(MVm-H  
String header=con.getHeaderFieldKey(i); /.u0rxoRP}  
if(header!=null) >[ox|_o  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?Hd/!I&  
Utility.log(header+" : "+con.getHeaderField(header));
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else #&cNR_"w  
break; *N;# _0)/  
} RN%*3{-  
} ,'m<YTF  
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public void splitterStop()  H?(I-vO  
{ VkNg Vjg  
bStop = true; W_E0+  
} {|kEGq~aE  
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} z[I3k  
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/* zNs8yMnFr  
**FileAccess.java s]"NqwIPK  
*//文件访问(定位，写) -Pr1
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package NetFox; MyyNYZ  
import java.io.*; X. =%  
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public class FileAccessI implements Serializable{ x
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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 (0=e ,1 n  
RandomAccessFile oSavedFile; H7xyK  
long nPos; /8(\AuDT  
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public FileAccessI() throws IOException m;S!E-W  
{ avb'J^}f  
this("",0); B
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} [LQD]#  
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public FileAccessI(String sName,long nPos) throws IOException YjTRz.e{[7  
{ P@m_tA%  
oSavedFile = new RandomAccessFile(sName,"rw"); )e$}sw{t  
this.nPos = nPos; MrW#~S|ED  
oSavedFile.seek(nPos); d%y)/5  
} =q%Q^  
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public synchronized int write(byte[] b,int nStart,int nLen) +ti_?gfx  
{ JfJLJ(}  
int n = -1; I,*zZNvRi  
try{ atW=xn  
oSavedFile.write(b,nStart,nLen); UkE fuH  
n = nLen; TJHab;7F  
} sUc_)  
catch(IOException e) ,[ UqUEO  
{ eCDwY:t`  
e.printStackTrace (); GI~JIXHTQ  
} yZ_6yJw3}  
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return n; 5cv&`h8uo_  
} 6%hr]>L  
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} m5wfQ_}}ss  
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/* ; S
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**SiteInfoBean.java b"lzR[X,e  
*/ WRa4g  
package NetFox; m44"qp  
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public class SiteInfoBean { C#^V<:9  
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private String sSiteURL; //Site's URL (;9-8Y&_d  
private String sFilePath; //Saved File's Path Y]xFe>  
private String sFileName; //Saved File's Name Z
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private int nSplitter; //Count of Splited Downloading File _(U|Kpi  
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public SiteInfoBean() D%=VhKq  
{//nSplitter的缺省值为5 B_gzpS]  
//default value of nSplitter is 5 kqebU!0-  
this("","","",5); lUL6L4m  
} ?5N7,|K)  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) t",=]k  
{
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sSiteURL= sURL; DRDn;j  
sFilePath = sPath; 6.!aJJLN  
sFileName = sName; eK=W'cNu  
this.nSplitter = nSpiltter; nY>UYSv  
 {"RUiL^  
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} Oc Gg'R7  
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public String getSSiteURL() 'n>v}__&|  
{ sjZ@}Vk3b  
return sSiteURL; gB3Tz(!  
} ii3{HJ*C  
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public void setSSiteURL(String value) {RmN1'%  
{ W~!uSrY  
sSiteURL = value; lYF~CNvE  
} m@Q%)sc)  
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public String getSFilePath() S'h{["P~ 0  
{ 1edeV48{:  
return sFilePath; IO@Ti(,  
} &y} ]^wB  
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public void setSFilePath(String value)  dcd9AW=  
{ +Fk]hCL  
sFilePath = value; {:63% j  
} iI]E%
H}  
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public String getSFileName() N!{waPbPi  
{ ,\DSi&T  
return sFileName; !,(6uO%  
} nNEIwlj;  
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![ce=9@t<  
public void setSFileName(String value) [X\<C '<  
{ ~+~^c|  
sFileName = value; )B!64'|M  
} Dcep^8'  
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public int getNSplitter() ?BEO(;'  
{
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return nSplitter; G
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} a,YU
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public void setNSplitter(int nCount) L'@@ewA  
{ C-TATH%f^  
nSplitter = nCount; GGWdMGI/  
} 4g
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} zz7#gU  
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/* pR,eus;8  
**Utility.java D-S"?aO-  
*/ *}Cm/li/w  
package NetFox; !</Snsi  
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public class Utility { Wu1">|  
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public Utility() K]Rb~+a<  
{ hgmo b"o  
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|/M^q{h&7s  
} A4mnm6Tf  
Ltrw)H}  
//线程睡眠 F5(DA  
public static void sleep(int nSecond) AB0>|.  
{ +*')0I
 
try{ .zQ'}H1.C  
Thread.sleep(nSecond); d>YX18'<Q  
} px~:'U  
catch(Exception e) .}4^b\  
{ lI&5.,2MP  
e.printStackTrace (); ro8c-[V  
} TEEt]R-y  
} ndE"v"_H  
LV6BSQyQ  
//日志 \5q0nB@i5y  
public static void log(String sMsg) h)o5j-M>4  
{ G,,7.%eib=  
System.err.println(sMsg); a?NoNv)&  
} =kiDW6 JJU  
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public static void log(int sMsg) c)q'" r  
{ '#ow9w+^  
System.err.println(sMsg); -n#fj;.2_  
} 1<n'F H3  
} j3$\+<m]  
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tsys</E&  
/* "NOll:5"(  
**TestMethod.java loByT p ^  
*/ .Z#8,<+  
package NetFox; F./$nwb  
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public class TestMethod { ZBxV&.9/  
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47
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public TestMethod() BqG7Et  
{ ///xx/weblogic60b2_win.exe C?-_8OA  
try{ D@iE2-n&V  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 
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//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); tFrNnbmlQ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \O G`+"|L  
fileFetch.start(); *{1]b_<  
} Cu-z`.#}R  
catch(Exception e){e.printStackTrace ();} ^>/] Qi  
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} zLS=>iLD{  
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public static void main(String[] args) rd hM#?  
{ K=Y{iH
n  
new TestMethod(); ~H\1dCW  
} #Ab,h#f*7  
}  &C&?kS(  
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