http断点续传简单实现（java)

/* Vh4z+JOC  
**SiteFileFetch.java W<v?D6dFq  
*/ Up)b;wR  
package NetFox; T?NwSxGo  
import java.io.*; Pg7W:L7  
import java.net.*; lOcvRF  
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public class SiteFileFetch extends Thread { '<$(*  
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SiteInfoBean siteInfoBean = null; //文件信息Bean W!V06.  
long[] nStartPos; //开始位置 BX2&tQSp  
long[] nEndPos; //结束位置 X62z>mM  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?cowey\m .  
long nFileLength; //文件长度 _sJp"4?  
boolean bFirst = true; //是否第一次取文件 x>p=1(L  
boolean bStop = false; //停止标志 !Kd/ lDY  
File tmpFile; //文件下载的临时信息 {#0B~Zr  
DataOutputStream output; //输出到文件的输出流 HO}aLp  
a{el1_DIGK  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） <iv9Mg
}  
public SiteFileFetch(SiteInfoBean bean) throws IOException _N0x&9S$  
{ 2mVH*\D  
siteInfoBean = bean; dV.)+X7<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 1K4LEga`  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); b{
(!Ls_ &  
if(tmpFile.exists ()) &3S;5{7_e  
{ FxD\F  
bFirst = false; Cf2rRH  
read_nPos(); ib*$3
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} DV]Kd 7  
else yV=hi?f-[V  
{ $bD 3  
nStartPos = new long[bean.getNSplitter()]; &h8+-  
nEndPos = new long[bean.getNSplitter()]; qeH#c=DQ  
} pcoJ\&&W  
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m
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} L)HuQVc g  
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public void run() %ktU 51o  
{ s[8<@I*u  
//获得文件长度 >x(^g~i  
//分割文件 =r:D]?8oC  
//实例FileSplitterFetch +SZ#s:#SE  
//启动FileSplitterFetch线程 @fPiGu`L  
//等待子线程返回 /,c9&it(M  
try{ HaJD2wvr  
if(bFirst) (*^_wq-;  
{ e8--qV#<  
nFileLength = getFileSize(); d+[hB4!l2  
if(nFileLength == -1) 71w  
{ F~)xZN3=  
System.err.println("File Length is not known!"); T1\.~]-msb  
} z^ KrR
 
else if(nFileLength == -2) SN\;&(
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{ vEW;~FLd  
System.err.println("File is not access!"); p+#uPY1#  
} 9Z6O{ >  
else D.
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{ BVC\~j j  
for(int i=0;i<nStartPos.length;i++) ! FhN(L[=j  
{ qwiM.b5  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "<txg%j\J  
}
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for(int i=0;i<nEndPos.length-1;i++) enDjP  
{ (LkGBnXE  
nEndPos = nStartPos[i+1]; !H~G_?Mf\O  
} M)i2)]FS  
nEndPos[nEndPos.length-1] = nFileLength; ERCW5b[RT  
} Vdh5s292h  
} CP["N(fF  
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p@YU7_sF^!  
//启动子线程 7z5AI!s_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; L&.9.Ll  
for(int i=0;i<nStartPos.length;i++) 1
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{ )LKutN?tBy  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), AdKv!Ta5b  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ko=v
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nStartPos,nEndPos,i); )zz"DH  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [;83 IoU}  
fileSplitterFetch.start(); M,3sK!`>  
} m7cp0+Peo  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xCiY jl$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [ !].G=8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ikw_t?  
nEndPos = " + nFileLength); #q6jE  
// fileSplitterFetch[nPos.length-1].start(); ?R#-
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Go=MG:`  
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//等待子线程结束 ZdY:I;)s  
//int count = 0; ")i4w{_y  
//是否结束while循环 |36d<b Io  
boolean breakWhile = false; (w6024~  
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while(!bStop) ^R! qxSj  
{ &
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write_nPos(); oDrfzm|[Y  
Utility.sleep(500); VK[^v;  
breakWhile = true; d3St Z~&r!  
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for(int i=0;i<nStartPos.length;i++) p?>(y  
{ bd5\Rt  
if(!fileSplitterFetch.bDownOver) ~*79rDs
{  
{ SRRqIQz  
breakWhile = false; 4%Z!*W*  
break; .!/DM-C  
} ;xS@-</:  
} sC(IeGbX
 
if(breakWhile) '-N `u$3Y  
break; ;QO3^P}  
#dA9v7  
|"}oGL6-  
//count++; =z>d GIT1  
//if(count>4) 43wm_4C!H  
// siteStop(); TrCut2  
} $, hHR:  
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System.err.println("文件下载结束！"); 6-E>-9]'E  
} \-Vja{J]  
catch(Exception e){e.printStackTrace ();} [}$jO,H5r  
} $8>kk  
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{ 9:vq|  
//获得文件长度 5Ve`j,`=<  
public long getFileSize() &u`EYxT  
{ [>$?/DM  
int nFileLength = -1; '\B0#z3  
try{ c,CcKy;+  
URL url = new URL(siteInfoBean.getSSiteURL()); .;\uh$c  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); dNu?O>=  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ztl?*zL  
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int responseCode=httpConnection.getResponseCode(); gV}c4>v(  
if(responseCode>=400) %1mIngW
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{ 0Q7|
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processErrorCode(responseCode); ?B+]Ex(\B,  
return -2; //-2 represent access is error A)#w~X4  
} 3AcS$.G  
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String sHeader; Qz4eQlWhp  
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for(int i=1;;i++) 3xk-D &"  
{ =AcK9?%5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); cYgd1  
//Utility.log(in.readLine()); U?%T~!  
sHeader=httpConnection.getHeaderFieldKey(i); 1B#iJZ}  
if(sHeader!=null) l(Ya,/4  
{ A]laS7Q  
if(sHeader.equals("Content-Length")) Cxd^i  
{ =pZ$oTR  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); I`77[  
break; %I=/ y  
} NQxx_3*4O  
} \kZ@2.pN  
else ;m=k FZ?  
break; V%(T#_E/6  
} 0.S7uH%
"  
} :9DyABK=Cv  
catch(IOException e){e.printStackTrace ();} ;qO3m-(d  
catch(Exception e){e.printStackTrace ();} 2#   
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Utility.log(nFileLength); QFK'r\3pU  
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return nFileLength; ? o&goiM  
} P2&0bNY  
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 9mW   
//保存下载信息（文件指针位置） # 0d7
  
private void write_nPos() EERCb%M8Z  
{ ~|[i64V<^  
try{ U'^ G-@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .}GOHW)}  
output.writeInt(nStartPos.length); <isU D6TC  
for(int i=0;i<nStartPos.length;i++) Y[|9 +T  
{ !<HF764@`  
// output.writeLong(nPos); 8>G5VhCm~o  
output.writeLong(fileSplitterFetch.nStartPos); 6-~ZOMlV  
output.writeLong(fileSplitterFetch.nEndPos); DQ}&J  
} :]4s;q:m  
output.close(); &lID6{79Z  
} uJ=d!Kn  
catch(IOException e){e.printStackTrace ();} 2I3H?Lrx!m  
catch(Exception e){e.printStackTrace ();} gil:SUW1r  
} sOVpDtZ]LR  
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//读取保存的下载信息（文件指针位置） 
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private void read_nPos() VeqB/QX  
{ GDs/U1[*  
try{  c_,pd  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); \[|X^8j  
int nCount = input.readInt(); mhM;`dl  
nStartPos = new long[nCount]; PT~F^8,)  
nEndPos = new long[nCount]; P9R-41!  
for(int i=0;i<nStartPos.length;i++) }O+S}Hbwy  
{ fLeHn,*,"  
nStartPos = input.readLong(); dKP| TRd  
nEndPos = input.readLong(); 3sRI7g  
} O2"@09:  
input.close(); C
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} YzJWS|]  
catch(IOException e){e.printStackTrace ();} Bio QV47B  
catch(Exception e){e.printStackTrace ();} l: kW|  
} A/&u/?*C  
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private void processErrorCode(int nErrorCode) uhv_'Q  
{ *3h_'3yo@  
System.err.println("Error Code : " + nErrorCode); m&#D~  
} OlptO60{ ]  
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//停止文件下载 .Wi%V"  
public void siteStop() I~E&::,  
{ nEP3B'+  
bStop = true; knzo6  
for(int i=0;i<nStartPos.length;i++) ^jcVJpyT@R  
fileSplitterFetch.splitterStop(); /!.]Y8yEH  
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} I.>8p]X  
} XWX]/j2jA  
//负责部分文件的抓取 E$A=*-u  
**FileSplitterFetch.java {%RwZ'  
*/ sO!m,p
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package NetFox; pV!WZUfg  
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import java.io.*; biForT_no  
import java.net.*; '|*e4n  
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public class FileSplitterFetch extends Thread { _KBa`lhE  
91nB?8ZE6,  
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String sURL; //File URL Ls3r( Tf  
long nStartPos; //File Snippet Start Position m( %PZ*s  
long nEndPos; //File Snippet End Position ka{!' ^  
int nThreadID; //Thread's ID T.B7QAI. H  
boolean bDownOver = false; //Downing is over W
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boolean bStop = false; //Stop identical R((KAl
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FileAccessI fileAccessI = null; //File Access interface W59xe&l  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (\wV)c9  
{ SLH;iqPT  
this.sURL = sURL; ttt4h  
this.nStartPos = nStart; <K>qK]|C  
this.nEndPos = nEnd; e5"5 U7  
nThreadID = id; G,1g~h%I$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 mtw{7E  
} r Cz,XYV  
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public void run() YM.  
{ RXu`DWN  
while(nStartPos < nEndPos && !bStop) 64<*\
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{ N-Bw&hEZ  
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try{ 0bSnD|#I  
URL url = new URL(sURL); S0LaQ<9.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *<h)q)HS  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8.7lc2aX  
String sProperty = "bytes="+nStartPos+"-"; '!`]Z
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httpConnection.setRequestProperty("RANGE",sProperty); m}>Q#IVZ  
Utility.log(sProperty); 41Ab,  
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InputStream input = httpConnection.getInputStream(); xX Dj4j,  
//logResponseHead(httpConnection); Y'#uZA3KA  
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byte[] b = new byte[1024]; K `A8N  
int nRead; kQn}lD
 
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 8kE3\#);\  
{ YlR9 1LX  
nStartPos += fileAccessI.write(b,0,nRead); IABF_GwF  
//if(nThreadID == 1) oR3t vw.  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m3&b)O7  
} vY,D02EMw  
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Utility.log("Thread " + nThreadID + " is over!"); Ue"pNjd|  
bDownOver = true; ~)6EH`-  
//nPos = fileAccessI.write (b,0,nRead); Y.#fpG'  
} tX,x%(  
catch(Exception e){e.printStackTrace ();} HK%W7i/k@  
} 2zuQeFsK  
} &VG  
_sY; dS/  
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//打印回应的头信息 ^uPg71r:  
public void logResponseHead(HttpURLConnection con) k~fH:X~x  
{ 7 y$a=+D i  
for(int i=1;;i++) iO2jT+i  
{ ,R-aO= %  
String header=con.getHeaderFieldKey(i); #wZH.i#  
if(header!=null) Qd>\{$N  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ,lFp4C  
Utility.log(header+" : "+con.getHeaderField(header)); o7eWL/1  
else 8Dn~U:F/?  
break; 91nw1c!  
} mU.c!|Y  
} xJA{Hws  
!/=.~B  
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public void splitterStop() \)ZC
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{ ;mPX8bT  
bStop = true; hML-zZ  
} IFhS(3YK[  
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} $dA]GWW5A  
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/* f[ia0w5 m  
**FileAccess.java 7+qKA1t^  
*//文件访问(定位，写) 8;#yXlf  
package NetFox; l[rK)PM  
import java.io.*; T''<yS  
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public class FileAccessI implements Serializable{ S5
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 G8!|Lo  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 M>}_2G]#F  
RandomAccessFile oSavedFile; 3rjKwh7  
long nPos; bZ``*{I/  
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public FileAccessI() throws IOException 
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{ p@[ fZj  
this("",0); AWKJ@&pA9m  
} ou-uZ"$,c  
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public FileAccessI(String sName,long nPos) throws IOException HrfS^B  
{ P{yb%@I~J  
oSavedFile = new RandomAccessFile(sName,"rw"); _l"nwE
s  
this.nPos = nPos;
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oSavedFile.seek(nPos); n?;rWq"  
} ;_2+Y^Qb  
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n.z,-H17  
public synchronized int write(byte[] b,int nStart,int nLen) xV 2C4K  
{ P;mp)1C  
int n = -1; aT(_c/t.  
try{ D W^Zuu/)  
oSavedFile.write(b,nStart,nLen); 44|tCB`  
n = nLen; a^pbBDi W  
} 9 <{C9  
catch(IOException e) Dad$_%  
{ qb/}&J7+  
e.printStackTrace (); Bc[~'gn  
} q=V'pML  
7(N+'8  
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return n; Y[
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} d7 H*F  
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} Y)+q[MZ R  
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/* $|.8@ nj  
**SiteInfoBean.java xZlCFu 
 
*/ ;}"Eqq:  
package NetFox; ne/JC(  
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y,3ZdY"  
public class SiteInfoBean { ,<r&] eC  
5UO+c(T  
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private String sSiteURL; //Site's URL mpMAhm
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private String sFilePath; //Saved File's Path !W9:)5^X  
private String sFileName; //Saved File's Name ow.!4kx{d  
private int nSplitter; //Count of Splited Downloading File
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Xa?O)Bq.  
pX?3inQP%(  
public SiteInfoBean() A>1$?A8Q  
{//nSplitter的缺省值为5 voRry6Q;  
//default value of nSplitter is 5 %BP>,E/w  
this("","","",5); '#Au~5  
} ]myRYb5Z
 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)  p;w&}l{{  
{ Aj4 a-vd.  
sSiteURL= sURL; MK=oGzK  
sFilePath = sPath; 7GYf#} N  
sFileName = sName; )hXTgUZa  
this.nSplitter = nSpiltter; d?2ORr|m=  
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} >+P}S@  
H@=oVyn/  
:ZV|8xI  
public String getSSiteURL() X8$Mzeq  
{ w`)5(~b  
return sSiteURL; 6]?mjG6  
} d_@ E4i  
f^uiZb  
olE(#}7V  
public void setSSiteURL(String value) ?e$&=FC0;  
{ c>_ti+  
sSiteURL = value; lFnls6dp  
} 4XjwU`  
f+
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public String getSFilePath() cag5w~Px  
{ .| 4P :r  
return sFilePath; {aY) Qv}  
} 0K%okq|n  
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public void setSFilePath(String value) Z7a@$n3h  
{ x77L"5
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sFilePath = value; >G6kF!V  
} GY%9V5GB  
o$*(N  
EN!C5/M{&  
public String getSFileName() =!'9TS  
{ [ohLG_9  
return sFileName; XV]N}~h o`  
} 8z`ZHn3=  
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,HZ%q]*:~  
public void setSFileName(String value) hIe.Mv-I)  
{ yYP_TuNa  
sFileName = value; fsL9d}  
} N%dY.Fk  
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)U %`7(bN  
public int getNSplitter() Ib..X&N2  
{ nwFBuP<LR  
return nSplitter; m_)-  
} `K{}  
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ojM'8z0Hn  
public void setNSplitter(int nCount) z!g$#hmL>  
{ KuJ)alD;1  
nSplitter = nCount; }yT/UlU  
} cW%)C.M  
} Y#F.{i  
 /a1uG]Mt  
<x}wy+SG  
/* j\ y!  
**Utility.java DTezG':  
*/ jEBn"]\D  
package NetFox; k4q":}M  
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public class Utility { n#X~"|U`  
8jz>^.-o  
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public Utility() {)qr3-EM#  
{ ._rPM>B?  
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l[E^nh>  
} {!

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c+FTt(\8.  
//线程睡眠 !<];N0nt#  
public static void sleep(int nSecond) /9_%NR[  
{ ~R|9|k  
try{ YoKE=ln7  
Thread.sleep(nSecond); ]aPf-O*  
} /h53;$zK  
catch(Exception e) T,!EL+o4  
{ #zsaQg, B  
e.printStackTrace (); (2b${Q@V  
} i]MemM-  
} ta?NO{*  
QT c{7&  
//日志 7T/BzXr,B  
public static void log(String sMsg) 6Q:Wo)^!  
{ h3`}{ w  
System.err.println(sMsg); yEWm.;&3=  
} .=eEuH  
znrO~OK  
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public static void log(int sMsg) ]T)N{"&N/  
{ Q"I(3 tp9[  
System.err.println(sMsg); z|Y54o3  
} $W7}Igx#  
} RG'iWA,9m`  
r|l?2 eO~  

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/* !yv>e7g^  
**TestMethod.java i(%2t(wf+  
*/ cvsH-uAp  
package NetFox; WK$\#>T  
6,5h4[eF*  
WVR/0l&bU  
public class TestMethod { _#V&rY&@  
}.o.*N  
93*d:W8Vr  
public TestMethod() X$UK;O  
{ ///xx/weblogic60b2_win.exe +q pW"0[  
try{ ;B@#,6t/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); CcUF)$kz  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); "SN*hzs"]`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *OA(v^@tx7  
fileFetch.start(); I/w;4!+)  
} D_dv8  
catch(Exception e){e.printStackTrace ();} Z7bJ<TpZ  
<( OHX3~  
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} 2OUx@Vj  
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public static void main(String[] args) curYD~7  
{ f+9WGNpw  
new TestMethod(); I8! .n  
} A5j?Yts  
} |@_<^cV110  
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