http断点续传简单实现（java)

/* Z:ni$7<.  
**SiteFileFetch.java 'iy*^A `Y  
*/ qNI, 62  
package NetFox; YiYV>gaf"H  
import java.io.*; vK(i9>;7  
import java.net.*; lW<PoT  
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public class SiteFileFetch extends Thread { -<Hu!V`+  
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SiteInfoBean siteInfoBean = null; //文件信息Bean TqNadHQ  
long[] nStartPos; //开始位置 b5,x1`#7k  
long[] nEndPos; //结束位置 J~%K_~Li  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 wpN
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long nFileLength; //文件长度 GGe,fb<k  
boolean bFirst = true; //是否第一次取文件 ;?W|#*=R  
boolean bStop = false; //停止标志 D*Ik7Pe  
File tmpFile; //文件下载的临时信息 ?
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DataOutputStream output; //输出到文件的输出流 y[>;]R7'  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ng:kA%! Q  
public SiteFileFetch(SiteInfoBean bean) throws IOException nM\eDNK  
{ 9
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siteInfoBean = bean; ;WgJ<&33  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >a"Z\\dF  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); GQ*wc?f3  
if(tmpFile.exists ()) A;5n:Sd  
{ ,B08i o-  
bFirst = false; SaC d0. h  
read_nPos(); _tSAI  
} 76>7=#m0u'  
else [v$0[IuY,  
{ a,3j,(3  
nStartPos = new long[bean.getNSplitter()]; cHcmgW\4  
nEndPos = new long[bean.getNSplitter()]; J~B<7O<?!1  
} 7Q7-vx  
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} 4VHqBQ4  
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public void run() n"+[ :w4  
{ dcLA1sN,  
//获得文件长度 k4,BNJt'Z  
//分割文件 fq5_G~c=  
//实例FileSplitterFetch C|d\3S\(  
//启动FileSplitterFetch线程 O@MGda9_;  
//等待子线程返回 /c"efnb!  
try{ ?|
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if(bFirst) !iH-#B-
 
{ bKj%s@x  
nFileLength = getFileSize(); PlF87j (  
if(nFileLength == -1) M~WijDj  
{ LUH"  
System.err.println("File Length is not known!"); RG3l.jL  
} SF}<{x_  
else if(nFileLength == -2) WX}xmtLs  
{ uum;q-"  
System.err.println("File is not access!"); )'/|)  
} umF Z?a  
else .fN"@l  
{ &j?#3Qt'_  
for(int i=0;i<nStartPos.length;i++) @

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{ <EPj$::  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); F6o_b4l  
} @Ys!DScY,  
for(int i=0;i<nEndPos.length-1;i++) !FA# K8  
{ L f"i !  
nEndPos = nStartPos[i+1]; c~{9a_G  
} @[#$J0qq  
nEndPos[nEndPos.length-1] = nFileLength; s <   
} "]oO{'1X  
} qb5#_1qz+^  
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//启动子线程 HS{(v;  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; AjJURn0`,!  
for(int i=0;i<nStartPos.length;i++) _<=S_<$2  
{ "jTKSgv+q5  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), NZP.0coY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), w?zKjqza=v  
nStartPos,nEndPos,i); 56e r`=ms  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); b !%hH  
fileSplitterFetch.start(); 7M<'ddAN  
} `W dD8E  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), lIUuA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); : p{+G  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", >$
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nEndPos = " + nFileLength); >*-FV{{  
// fileSplitterFetch[nPos.length-1].start(); lc2i`MC  
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//等待子线程结束 j [rB"N`0  
//int count = 0; |,#t^'S!  
//是否结束while循环 MZTx:EN!  
boolean breakWhile = false; yu6`66h)  
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while(!bStop) is1's[  
{ ;w6>"O$a  
write_nPos(); }j2Y5  
Utility.sleep(500); rC.eyq,105  
breakWhile = true; 'mH)d  
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for(int i=0;i<nStartPos.length;i++) {/X4(;~0  
{ 4q'B<7{Q  
if(!fileSplitterFetch.bDownOver) :N<.?%Kf  
{ d~/q"r1"  
breakWhile = false; JCPUM*g8  
break; #'-Sh7ycW  
} UK$ms~H  
} v
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if(breakWhile) 6*qL[m.F[o  
break; @*0cMO;SpG  
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//count++; 21ppSN>  
//if(count>4) }w/;){gu  
// siteStop(); Iq#ZhAk  
} -pU|hSW*b  
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System.err.println("文件下载结束！"); oT{@_U{*J  
} $`8Ar,Xz`  
catch(Exception e){e.printStackTrace ();} E,wVe[0)f  
} ZT[3aXS  
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//获得文件长度 Yz4_vePh+5  
public long getFileSize() N%7{J  
{ m6MOW&  
int nFileLength = -1; \":?xh_H  
try{ E]J:~H'Er  
URL url = new URL(siteInfoBean.getSSiteURL()); R g?1-|Tj  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
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httpConnection.setRequestProperty("User-Agent","NetFox"); ;>%~9j1C  
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'
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int responseCode=httpConnection.getResponseCode(); 5jgdbHog]  
if(responseCode>=400) '=E3[0W  
{ uk9g<<3T  
processErrorCode(responseCode); Zes+/.sA}]  
return -2; //-2 represent access is error Wxkx,q?  
} Nrah;i+H\o  
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String sHeader; 9D 0dg(  
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for(int i=1;;i++) 7QVuc!V  
{ g|Y] wd  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); O<jPGU  
//Utility.log(in.readLine()); {/LZcz[  
sHeader=httpConnection.getHeaderFieldKey(i); 9'DtaTmGW  
if(sHeader!=null) 3IR ^  
{ >#}2J[2HQ  
if(sHeader.equals("Content-Length")) N7%TYs  
{ FP#FB$eP  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 7l."b$U4yv  
break; .c^ ggy%  
} _
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} ~gI{\iNF/  
else /<&h@$NHH4  
break; yMc:n"-[  
} 6yu]GK}es  
} kvGCbRC  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} ?X9]HlH  
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Utility.log(nFileLength); SQWa
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return nFileLength; Ogg#jx(4  
} Jqr

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//保存下载信息（文件指针位置） RGD
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private void write_nPos() a :HNg  
{ G",.,Px  
try{ `nJu?5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Ybg-"w  
output.writeInt(nStartPos.length); Zg:gY"^  
for(int i=0;i<nStartPos.length;i++) p"`
%  
{ -Dzsa  
// output.writeLong(nPos); ,Vd7V}t  
output.writeLong(fileSplitterFetch.nStartPos); BF8"rq}r0  
output.writeLong(fileSplitterFetch.nEndPos); JmOW~W  
} -DO&_`kn  
output.close(); wk\L*\@Y}  
} %do1i W  
catch(IOException e){e.printStackTrace ();} h4fLl3%H  
catch(Exception e){e.printStackTrace ();} pKJK9@Ad  
} LD(C\  
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//读取保存的下载信息（文件指针位置） cs_}&!c{  
private void read_nPos() Zv qn%K],  
{ $T }Tz7(  
try{ \ Aq;Q?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); BH@b1}  
int nCount = input.readInt(); TSo:7&|  
nStartPos = new long[nCount]; (E($3t8  
nEndPos = new long[nCount]; Xt,X_o2m|]  
for(int i=0;i<nStartPos.length;i++) FN )d1q(~  
{ 2H[)1|]l  
nStartPos = input.readLong(); IS]{}Y\3H  
nEndPos = input.readLong(); <%bw
/  
} `Y3(~~YGn  
input.close(); iRV;Fks  
} :kw0y  
catch(IOException e){e.printStackTrace ();} $V8vrT#:  
catch(Exception e){e.printStackTrace ();} 2HOe__Ns  
} 0^_MN~s(X  
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private void processErrorCode(int nErrorCode) HdQj?f3  
{ bY#;E;'7  
System.err.println("Error Code : " + nErrorCode); %my
  
} ,5-Zb3\  
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//停止文件下载 =B5E0x  
public void siteStop() R "E<8w  
{ Hc!!tbBQ  
bStop = true; jmW^`%;7  
for(int i=0;i<nStartPos.length;i++) !Q[}s#g  
fileSplitterFetch.splitterStop(); ;?im(9h"v!  
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} =jIxI,  
} 2oNV=b[  
//负责部分文件的抓取 ZDlu1>Q  
**FileSplitterFetch.java :c;_a-69  
*/ 3bH5C3(u  
package NetFox; my[,w$YM  
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import java.io.*; wF;B@  
import java.net.*; T#e4":A&x  
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public class FileSplitterFetch extends Thread { n8FT<pUq  
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String sURL; //File URL b3^R,6]x&  
long nStartPos; //File Snippet Start Position (6#M9XL  
long nEndPos; //File Snippet End Position 9L
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int nThreadID; //Thread's ID (1y='L2rj  
boolean bDownOver = false; //Downing is over zg0%>iqO  
boolean bStop = false; //Stop identical rIp'vy S\p  
FileAccessI fileAccessI = null; //File Access interface gN\*Y  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6BPAux.]  
{ NV(fN-L  
this.sURL = sURL; R8{e&nPE  
this.nStartPos = nStart; b60[({A\s&  
this.nEndPos = nEnd; <"NyC?b+G  
nThreadID = id; _s@bz|yqw  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (l;C%O7*  
} 09x+Tko9;*  
4 f3=`[%  
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public void run() |<QI%Y$dr  
{ wV %8v\  
while(nStartPos < nEndPos && !bStop) V4oak!}?  
{ >~>{;Wq(p+  
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try{ {SHqW5VX  
URL url = new URL(sURL); /9TL&_A-T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); iZu:uMoc  
httpConnection.setRequestProperty("User-Agent","NetFox"); lSs^A@s  
String sProperty = "bytes="+nStartPos+"-"; aC}vJ93i  
httpConnection.setRequestProperty("RANGE",sProperty); I<9n(rA  
Utility.log(sProperty); I4CHfs"ar  
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$ #t|(\  
InputStream input = httpConnection.getInputStream(); U!.~XT=  
//logResponseHead(httpConnection); (,d/JnP  
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byte[] b = new byte[1024]; o9~h%&  
int nRead; ;4R=eI  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Y]M^n&f
 
{ u% r!?-z  
nStartPos += fileAccessI.write(b,0,nRead); IMw
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//if(nThreadID == 1) 1Q0%7zRirI  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;!^ +N  
} Vx}Yl&*D  
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Utility.log("Thread " + nThreadID + " is over!"); XX*'N+  
bDownOver = true; 9$:QLE+t  
//nPos = fileAccessI.write (b,0,nRead); uT'-B7N  
} d?Ia#K93G  
catch(Exception e){e.printStackTrace ();} &S9f#Ui  
} Wk0>1 rlu  
} h85(N  
)PsN_ 42~  
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//打印回应的头信息 z"G`o"4 V  
public void logResponseHead(HttpURLConnection con) Mp]yKl  
{ jc${.?m  
for(int i=1;;i++) aW52.X z%8  
{ 5xG|35Pj  
String header=con.getHeaderFieldKey(i); KyuA5jQ7  
if(header!=null) g,A.Y,})  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); DBqg_v  
Utility.log(header+" : "+con.getHeaderField(header)); Pmqx ;  
else n25irCD`  
break; ORV}j,Ym  
} V%X:1 8j  
} c
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public void splitterStop() ?Zc/upd:$N  
{ >reaIBT  
bStop = true; d~togTs1  
} y
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} +YGw4{\EL  
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/* [dSDg2]  
**FileAccess.java f:x9Y{Y  
*//文件访问(定位，写) T% /xti5$!  
package NetFox; ~!
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import java.io.*; WHpUjyBP  
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public class FileAccessI implements Serializable{ yFPaWW  
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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 E
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RandomAccessFile oSavedFile; = )JVT$]w  
long nPos; 7- *(
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+ d+hvwEM  

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public FileAccessI() throws IOException imJ[:E  
{ L|C1C cP  
this("",0); p]1yd;Jt  
} w(vE2Y ?  
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public FileAccessI(String sName,long nPos) throws IOException W|r+J8  
{  BdE`p{  
oSavedFile = new RandomAccessFile(sName,"rw"); ,E/Y@sajn+  
this.nPos = nPos; m p|20`go  
oSavedFile.seek(nPos); *D09P%  
} 6`s%%v  
E.H,1 {  
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public synchronized int write(byte[] b,int nStart,int nLen) 1a=9z'8V  
{ 5Sm5jRr  
int n = -1; M0Kh>u  
try{ 7q2"b?|h  
oSavedFile.write(b,nStart,nLen); c
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n = nLen; zT4ulXN  
} $_URXI  
catch(IOException e) xM'S ;Sg  
{ d=4f`q0k  
e.printStackTrace (); }!Diai*C  
} v]`A_)[  
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return n; /n(bThDH  
} Rbj+P;t&  
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} AHMV@o`V  
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/* PgG |7='  
**SiteInfoBean.java [b k&Nd[  
*/ B0oY]r6  
package NetFox; s68_o[[E  
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$?/Xk%d+  
public class SiteInfoBean { @)2V"FE4i  
@R OY}CZ{/  
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private String sSiteURL; //Site's URL CI,`R&=xO  
private String sFilePath; //Saved File's Path Q~w G(0'8  
private String sFileName; //Saved File's Name 1$!RKqT  
private int nSplitter; //Count of Splited Downloading File 
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public SiteInfoBean() ,m?UFRi  
{//nSplitter的缺省值为5 ?_Dnfa_  
//default value of nSplitter is 5 #G!Adj+p5  
this("","","",5); 'MdE}  
} tzW<&^  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 't]EkH]BC  
{ da?th  
sSiteURL= sURL; o4[2`mT  
sFilePath = sPath; :{xN33@6\X  
sFileName = sName; M(h H#_$  
this.nSplitter = nSpiltter; ;\*Od?1  
,@>rubUz  
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} -SY:qG3?  
|nH0~P#!  
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/  
public String getSSiteURL() j3[OY  
{ &!YH"{b  
return sSiteURL; *r?51
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} ='bmjXu  
~"rwP=<}  
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public void setSSiteURL(String value) 33KPo0g7  
{ ~Yz/t  
sSiteURL = value; np\Q&  
} +heS\I_Mp  
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public String getSFilePath() pnA]@FW  
{ ccR
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return sFilePath; z3jzpmz  
} OI}HvgV^!  
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public void setSFilePath(String value) Cm}UWX  
{ ,sJfMY  
sFilePath = value; rnhf(K.{3  
} (l P4D:X  
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public String getSFileName() qf=[*ZY  
{ dVt@D&  
return sFileName; }7
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} x7
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public void setSFileName(String value) U?ic$J]N  
{
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sFileName = value; j6HbJ#]  
} ,h`D(,?X  
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public int getNSplitter() # %y{mn  
{ x,c68Q)g  
return nSplitter; @Be:+01z  
} aw"%B-N\  
/aa;M*Qp  
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public void setNSplitter(int nCount) hPpXB:(-0  
{ ;k%sKVP  
nSplitter = nCount; HPdwx V  
} ZL@DD(S-/  
} \ g(#)f  
(*Q|;  
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/* ^k<$N  
**Utility.java 1p<?S}zg@  
*/ :tG".z  
package NetFox; K y2xWd8  
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public class Utility { 4H?Ma|,  
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public Utility() WA\f`SRF  
{ +i!M[  
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} !jq6cND  
q;PzB4#  
//线程睡眠 3D dG$@  
public static void sleep(int nSecond) (3r,PS@Qq@  
{ TC#B^m`'p  
try{ 2U+p@}cQUA  
Thread.sleep(nSecond); 3 v$
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} #7T={mh  
catch(Exception e) J5IJy3d  
{ u.Yb#?  
e.printStackTrace (); X*"O'XCA  
} bd*(]S9d  
} L/LNX{|  
l>?vjy65  
//日志 DkKD~  
public static void log(String sMsg)  /?xn  
{ 9cj-v}5j  
System.err.println(sMsg); HKw:fGt/o^  
} F|Ihq^q  
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public static void log(int sMsg) ?R:Hj=.  
{ ~At.V+  
System.err.println(sMsg); 'oL[rO~j  
} Li^!OHro.  
} c6)zx b  
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O^%ace1  
/* /k"P4\P`+Q  
**TestMethod.java K!gFD
  
*/ ^v|!(h\ZC  
package NetFox; Hv*O9!cC  
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public class TestMethod { GTNTx5H  
b
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public TestMethod() a8aqcDs>O  
{ ///xx/weblogic60b2_win.exe #8OqX*/  
try{ 
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); r=aQS5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); q~_jF$9SX  
SiteFileFetch fileFetch = new SiteFileFetch(bean); i=QhXCM  
fileFetch.start(); iUBni&B  
} U.(_n  
catch(Exception e){e.printStackTrace ();} BIyG[y?qO  
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'=* 5C{  
} Ft!~w#&-  
59 Y=VS
 
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public static void main(String[] args) H4Ek,m|c  
{ L1i> %5:g  
new TestMethod(); )D*xOajo+l  
} h--bN*}H2  
} HI 61rXNF  
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