http断点续传简单实现（java)

/* [i,5>YIk
 
**SiteFileFetch.java m _t(rn~f6  
*/ o'x_g^ Y  
package NetFox; K9x*Sep  
import java.io.*; w3>Y7vxiz`  
import java.net.*; >m)2ox_B  
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public class SiteFileFetch extends Thread { zJB+C=]D7H  
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SiteInfoBean siteInfoBean = null; //文件信息Bean : L6-{9$  
long[] nStartPos; //开始位置 44/0}v]  
long[] nEndPos; //结束位置 C%x(`S^/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 kVB}r.NHP  
long nFileLength; //文件长度 MkluK=$  
boolean bFirst = true; //是否第一次取文件 (HTk;vbZm  
boolean bStop = false; //停止标志 MJ*oeI!.=  
File tmpFile; //文件下载的临时信息 S`'uUvAA  
DataOutputStream output; //输出到文件的输出流 BIb{<tG^N  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） AW{/k'%xw  
public SiteFileFetch(SiteInfoBean bean) throws IOException K>DnD0  
{ d~Z:$&r  
siteInfoBean = bean; K|Ij71  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #!<+:y'S?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 4`^TC[
  
if(tmpFile.exists ()) FZ}C;yUPD  
{ r*
 
bFirst = false; BT*K,p  
read_nPos(); *}Ae9  
} h
} b^o*  
else -*]9Ma<wa  
{ ^/5E773  
nStartPos = new long[bean.getNSplitter()]; tM?I()Y&P  
nEndPos = new long[bean.getNSplitter()]; lw/
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} T_;G))q'  
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} {&Ju
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public void run() enfu%"(K)  
{ -%QEzu&  
//获得文件长度 })=c:h&  
//分割文件 "~,(
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//实例FileSplitterFetch B )3SiU  
//启动FileSplitterFetch线程 daokiU+l2  
//等待子线程返回 x:D<Mu#  
try{ iz|9a|k6x  
if(bFirst) >Gu>T\jpe.  
{ 0%L$TJ.''  
nFileLength = getFileSize(); _ER cmP  
if(nFileLength == -1) w]}cB+C+l#  
{ (^OC%
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System.err.println("File Length is not known!"); B2+_F"<;  
} y`P7LC  
else if(nFileLength == -2) OKNs (H  
{ ,?skJ  
System.err.println("File is not access!"); (Gb{ckzs  
} Ns7l-mb  
else uC$4TnoQx.  
{ W SeRV?+T  
for(int i=0;i<nStartPos.length;i++) [}g5Z=l  
{ *{n,4d\..  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); -wHGi  
} K {N;k-  
for(int i=0;i<nEndPos.length-1;i++) <8}9s9Nk  
{ iegPEb  
nEndPos = nStartPos[i+1]; U";Rp&\3;  
} %4g4 C#  
nEndPos[nEndPos.length-1] = nFileLength; }t{^*(  
} peP:5WB  
} ZCq\Zk1O&  
J'&?=|  
<@2?2l+`X  
//启动子线程 J+Y|# U  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; P6Ol+SI#m  
for(int i=0;i<nStartPos.length;i++) (IWd?,H,n  
{ Gl\RAmdc  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =$`")3y3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), S%%qn  
nStartPos,nEndPos,i); +hY
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !Kn+*'#  
fileSplitterFetch.start(); Ts *'f  
} O4+w2'.,  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R(#;yn  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); /]UNN~(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5 BG&r*U  
nEndPos = " + nFileLength); 206jeH9  
// fileSplitterFetch[nPos.length-1].start(); #k]0[;1os  
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//等待子线程结束 Y2~{qY  
//int count = 0; {;gWn'aq  
//是否结束while循环 )bJ6{&  
boolean breakWhile = false; (9QRg;   
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while(!bStop) 2{q
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{ k3eN;3#&  
write_nPos(); ;^SgV   
Utility.sleep(500); DO*C]   
breakWhile = true; 9Ei#t FMc  
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for(int i=0;i<nStartPos.length;i++) e=$xn3)McY  
{ 7
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if(!fileSplitterFetch.bDownOver) y
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{ R9HS%O6b6  
breakWhile = false; _Xe< JJvq  
break; UYLI>XSd  
} )W3l{T(  
} cSWVHr  
if(breakWhile) /v<8x?=  
break; :O=Vr]Y8K  
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}z:=b8}  
//count++; p =O1aM  
//if(count>4) msJn;(Pn  
// siteStop(); b8Sl3F?
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} dRC+|^rSC  
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System.err.println("文件下载结束！"); lsf?R'1  
} S}yb
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catch(Exception e){e.printStackTrace ();} 6ng9 o6  
} zh#uwT1u  
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//获得文件长度 ]>j_ Y,  
public long getFileSize() ~<-h# B  
{ /pEkig7M  
int nFileLength = -1; $x0F(|wxt  
try{ 1Tkz!  
URL url = new URL(siteInfoBean.getSSiteURL()); =25"qJr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j'cS_R  
httpConnection.setRequestProperty("User-Agent","NetFox"); w?"l4.E%  
/GNYv*  
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int responseCode=httpConnection.getResponseCode(); 7 |A,GH  
if(responseCode>=400) >^}z  
{ l"
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processErrorCode(responseCode); [sRQd;+  
return -2; //-2 represent access is error ':
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} z9ZAY!Zhq]  
nz
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String sHeader; =XB)sC%  
8X5XwFf}  
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for(int i=1;;i++) ?*0kQo'  
{ !h~\YE)  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); a6OT2B  
//Utility.log(in.readLine()); wH.'E
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sHeader=httpConnection.getHeaderFieldKey(i); 0v?,:]A0E  
if(sHeader!=null) .N2Yxty8>  
{ J\BdC];  
if(sHeader.equals("Content-Length")) 7Fx8&Z  
{  '}=M~
 
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2I  
break; @2<J_Ja  
} $Z4p$o dk  
} ]Yy S
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else [iD!!{6+  
break; xN]bRr  
} *gnL0\
*  
} SzDi=lY  
catch(IOException e){e.printStackTrace ();} ()Z$j,2  
catch(Exception e){e.printStackTrace ();} $A,=z  
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//(c 1/s  
Utility.log(nFileLength); .6*A~%-=[d  
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return nFileLength; ,3K?=e2  
} R?(j#bk  
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//保存下载信息（文件指针位置） Nb6HM~  
private void write_nPos() W*0KAC`m  
{ {!w]t?h  
try{ l6~eb=u;9g  
output = new DataOutputStream(new FileOutputStream(tmpFile)); p5*Y&aKj  
output.writeInt(nStartPos.length); Ok@5`?08  
for(int i=0;i<nStartPos.length;i++) :MpCj<<[  
{ @AwH?7(b  
// output.writeLong(nPos); _Cs.%R!r  
output.writeLong(fileSplitterFetch.nStartPos); q/Q*
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output.writeLong(fileSplitterFetch.nEndPos);  :2?du  
} V\_ &2',t  
output.close(); ^l9S5 {  
} C-Mop,w  
catch(IOException e){e.printStackTrace ();} fu`oDi  
catch(Exception e){e.printStackTrace ();} l}m@9 ~oC  
} tNjrd}8s  
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//读取保存的下载信息（文件指针位置） ^^v!..V]J  
private void read_nPos() Ne=D$o  
{ uwbj`lpf  
try{ vm(% u!_P  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); j
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int nCount = input.readInt(); NTV0DkX  
nStartPos = new long[nCount]; fE(rDQI  
nEndPos = new long[nCount]; H*Yyo?  
for(int i=0;i<nStartPos.length;i++) /h_BF\VBs  
{
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nStartPos = input.readLong(); &ha39&I  
nEndPos = input.readLong(); BM3nZ<%3  
} 9N9;EY-U  
input.close(); =KX:&GU  
} hgm`6TQ  
catch(IOException e){e.printStackTrace ();} C&Rv)
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catch(Exception e){e.printStackTrace ();} qp7>_B  
} NJ|8##Z>  
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private void processErrorCode(int nErrorCode) #{0c01JZ  
{ RJ0w3T]7  
System.err.println("Error Code : " + nErrorCode); SW bwD/SN  
} ]86U-`p  
oM< 9]jK}  
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//停止文件下载 ]]Wa.P~]O  
public void siteStop() rt f}4.  
{ s{gdTG6v`  
bStop = true; g4Tc (k#  
for(int i=0;i<nStartPos.length;i++) 5{{u #W%=  
fileSplitterFetch.splitterStop(); KX{S8_  
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} 9Czc$fSSt  
} 'y@0P5[se  
//负责部分文件的抓取 S/8xo@vct]  
**FileSplitterFetch.java ~/QzL.S;p  
*/ pm^[ve  
package NetFox; SFTThM]8M1  
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import java.io.*; L~~;i'J  
import java.net.*; o: qB#8X  
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public class FileSplitterFetch extends Thread { >wZ!1Jq  
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String sURL; //File URL D.X%wJ8  
long nStartPos; //File Snippet Start Position &vo]l~.  
long nEndPos; //File Snippet End Position )0YMi!&j`  
int nThreadID; //Thread's ID .Q4EmpByCg  
boolean bDownOver = false; //Downing is over flnoK%wi  
boolean bStop = false; //Stop identical I@e{>}  
FileAccessI fileAccessI = null; //File Access interface yPKeatH]  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException y1B3F5  
{ MYDAS-  
this.sURL = sURL; .(ki(8Z N  
this.nStartPos = nStart; aOETmsw  
this.nEndPos = nEnd; Ub%5# <k|-  
nThreadID = id; 7C F
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 :k#Y|(  
} $s5LzJn  
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public void run() ['Hl$2 j  
{ 3t)07(x_B  
while(nStartPos < nEndPos && !bStop) c\065#f!  
{ ?l &S:` L  
@/g%l1$`  
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try{ q]DV49UK  
URL url = new URL(sURL); M|w;7P}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o+r?N5  
httpConnection.setRequestProperty("User-Agent","NetFox"); RQ;pAO  
String sProperty = "bytes="+nStartPos+"-"; %A|9=x*  
httpConnection.setRequestProperty("RANGE",sProperty); @2nar<  
Utility.log(sProperty); qH1[BsOx  
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InputStream input = httpConnection.getInputStream(); `A_CLVE  
//logResponseHead(httpConnection); Z%E;*R2+:>  
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byte[] b = new byte[1024]; dDK4
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int nRead; B4Ko,=pg  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) O/Ub{=g  
{ O~?H\2S  
nStartPos += fileAccessI.write(b,0,nRead); &@p_g8r#  
//if(nThreadID == 1) P:,' 
 
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Up*1j:_O  
} w\ 4;5.$  
1zqIB")s>  
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Utility.log("Thread " + nThreadID + " is over!"); `K5Lp>=R  
bDownOver = true; -FftEeo7  
//nPos = fileAccessI.write (b,0,nRead); <#/r.}.x  
} O<[h  
catch(Exception e){e.printStackTrace ();} 5tfD*j n  
} zW.I7Z0^  
} 8S/SXyS  
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//打印回应的头信息 {,xI|u2R  
public void logResponseHead(HttpURLConnection con) }%2hBl/
  
{ mqe83 k%  
for(int i=1;;i++) cBcfGNTJ~  
{ $]LhE:!G  
String header=con.getHeaderFieldKey(i); {;mT.[  
if(header!=null) Uao8#<CkvJ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); rG[iEY  
Utility.log(header+" : "+con.getHeaderField(header)); ]+4QsoFNt  
else )bqSM&SO  
break; <KY \sb9  
} +\Uq=@  
} zy8Z68%E`*  
q~:H>;:G-  
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public void splitterStop() J n>3c  
{ ?OjZb'+=K  
bStop = true; ]? 2xS?vd  
} lB)%s~P:s  
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} ~t=73fwB  
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/* }^Ymg
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**FileAccess.java fI<|]c}P&J  
*//文件访问(定位，写) [KcF0%a  
package NetFox; ;r8< Ed
  
import java.io.*; zjE|UK{  

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public class FileAccessI implements Serializable{ ]`+J!G,  
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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 g$/C-j4A[  
RandomAccessFile oSavedFile; 7=hISQMsVP  
long nPos; u=QG%O#B  
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public FileAccessI() throws IOException D`9a"o  
{ &"gQrBa  
this("",0); QJ4=*tX)  
} ztEM>xsk  
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public FileAccessI(String sName,long nPos) throws IOException F[@M?  
{ )lhPl  
oSavedFile = new RandomAccessFile(sName,"rw"); #@UzOQ>  
this.nPos = nPos; aam6R/
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oSavedFile.seek(nPos); S"<"e\\}"_  
} ?9Hs,J  

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public synchronized int write(byte[] b,int nStart,int nLen) <*Bk.>f!  
{ ']&rPvkL  
int n = -1; Z1dLC'/b]  
try{ EEJ OJ<  
oSavedFile.write(b,nStart,nLen); vT=?U
Tq  
n = nLen; )`z{T  
} /^pPT6  
catch(IOException e) .,*68S0k7  
{ +1pY^#A  
e.printStackTrace (); qP5'&!s&!  
} &:?2IAe  
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return n; MhL>6rn  
} /H'F4->  
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} %] #XIr  
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/* :vXlni7N[M  
**SiteInfoBean.java cCBYM  
*/ G
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package NetFox; mx=2lL`  
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public class SiteInfoBean { x='T`*HD  
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private String sSiteURL; //Site's URL a+=.
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private String sFilePath; //Saved File's Path HP(dhsd<c  
private String sFileName; //Saved File's Name lN~V1(1B  
private int nSplitter; //Count of Splited Downloading File xe@11/F  

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public SiteInfoBean() 4apaUP=Jp  
{//nSplitter的缺省值为5 vw)lD9-"  
//default value of nSplitter is 5 Me2qOc^Z-  
this("","","",5); zEy,aa:M  
} ',bSJ4)Y  
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2Fc>6]:*  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) SUN!8 qFA  
{ k1E(SXcW9  
sSiteURL= sURL; kK~,?l  
sFilePath = sPath; nm#,oX2C  
sFileName = sName; 60z8U#upM  
this.nSplitter = nSpiltter; V.|#2gC]t  
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} (~N[j;W,_W  
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public String getSSiteURL() #p7K2  
{ $(fhO  
return sSiteURL; !g7lJ\
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} Xj5oHHwn  
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public void setSSiteURL(String value) 952l1c!
  
{ y8j6ttQv=t  
sSiteURL = value; 2Y~nU(  
} 0b(x@>
 
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public String getSFilePath() l05'/duuJ  
{ *!^l ZpF  
return sFilePath; enT[#f[{  
} |*(
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public void setSFilePath(String value) -?p4"[
 
{ {Jc.49  
sFilePath = value; :Z&<5  
} ^v5<*uf%m  
<Uc?#;%Y}  
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public String getSFileName() ./35_Vy/O  
{  7 T  
return sFileName; yJ4ZB/ZQ  
} Zo<j"FG  
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public void setSFileName(String value) <,*3Av  
{ ,lcSJ^yr  
sFileName = value; NwyNl  
} K%ptRj$  
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?$#P =VK  
public int getNSplitter() ^
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{ yA#nnu1  
return nSplitter; 4L_)@n}  
}
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public void setNSplitter(int nCount) AsI\#wL)  
{  <HnpI  
nSplitter = nCount; hp`ZmLq/[  
} 55FRPNx-x  
} /gn!="J  
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/* k [LV^oEg  
**Utility.java c\;_jg  
*/ >Ptu-*  
package NetFox; GvZ[3GT  
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*M/:W =,t  
public class Utility { zdm2`D;~p  
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public Utility() THARr#1b};  
{ '50}QY_R.  
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}  md,KRE  
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//线程睡眠 !ewT#afyu(  
public static void sleep(int nSecond) t3h){jZ  
{ Sy']fGvx  
try{ %DA&txX}w  
Thread.sleep(nSecond); o7s!ti\G  
} kD0bdE|  
catch(Exception e) H'JU5nE  
{ 
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e.printStackTrace (); F0~<p[9Nx  
} [N12X7O3  
} f!{@
{\  
K:^0*5Y-k  
//日志 ITg<u?z_  
public static void log(String sMsg) -QwH|  
{ G{I),Y~IF  
System.err.println(sMsg); 4Us_Z{.  
} yRIXUCy  
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public static void log(int sMsg) Svb>s|D  
{ Inn{mmz 1  
System.err.println(sMsg); YM};85K  
} * k<@  
} aZ+><1TD  
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/* :PtZKt;~X  
**TestMethod.java ~USt&?  
*/ 1Qu@pb^  
package NetFox; |JP19KFx'B  
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public class TestMethod { R|v'+bv  
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public TestMethod() xDGS`o_w_  
{ ///xx/weblogic60b2_win.exe o<G#%9j  
try{ a&V;^ /  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); R(`:~@3\6  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); D}q"^"#T  
SiteFileFetch fileFetch = new SiteFileFetch(bean); tq}45{FH3  
fileFetch.start(); m3TR}=n  
} u8]FJQ*\6+  
catch(Exception e){e.printStackTrace ();} MUAs(M;  
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} xH xTL>,?  
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public static void main(String[] args) PO`p.("h  
{ Aeb(b+=  
new TestMethod(); pK@=]K~l0  
} 8.[F3Tk=  
} Jsysk $R  
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