http断点续传简单实现（java)

/* .R5z>:A  
**SiteFileFetch.java 92Iv'(1ba  
*/ b@hoH)<9E  
package NetFox; 2Wtfx" .y  
import java.io.*; 7Y:s6R|  
import java.net.*; 5{TF6  
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public class SiteFileFetch extends Thread { [y>.)BU  
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SiteInfoBean siteInfoBean = null; //文件信息Bean OQvJdjST  
long[] nStartPos; //开始位置 xd<68%Cn  
long[] nEndPos; //结束位置 +\chHOsw  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 + aFjtb  
long nFileLength; //文件长度 qcF{Kex"  
boolean bFirst = true; //是否第一次取文件 }=FQKqtC  
boolean bStop = false; //停止标志 l1S1CS  
File tmpFile; //文件下载的临时信息 NQ!F`  
DataOutputStream output; //输出到文件的输出流 Nfh(2gK+  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） DJ^JUVi  
public SiteFileFetch(SiteInfoBean bean) throws IOException :e;fs.C  
{ IYPLitT  
siteInfoBean = bean; cS"6%:hQ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); l-rnDl  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); kn.z8%^(  
if(tmpFile.exists ()) jG#sVK]  
{ >smaR^m  
bFirst = false; ( 9l|^w["  
read_nPos(); {PKER$C  
} q8J/tw?%v  
else \q>,c49a{  
{ M*N8p]3Cq  
nStartPos = new long[bean.getNSplitter()]; "oQ@.]-#  
nEndPos = new long[bean.getNSplitter()]; m[f\I^\%8  
} )j]RFt  
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*
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} !IS,[  
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public void run() Sa0\93oa  
{ sIpK@BQ'  
//获得文件长度 o>YRKb  
//分割文件 '};Xb|msU  
//实例FileSplitterFetch RUEUn  
//启动FileSplitterFetch线程 ?=l(29tH  
//等待子线程返回 rZEu@6
3  
try{ 19S,>  
if(bFirst) e/6oC~#]  
{ {f)p|)  
nFileLength = getFileSize(); LYX+/@OU2  
if(nFileLength == -1) d={}a,3?  
{ <Wd$6  
System.err.println("File Length is not known!"); L`\ILJz  
} i=ba=-"Mt  
else if(nFileLength == -2) t`?FSV  
{ _heQ|'(  
System.err.println("File is not access!"); (.c?)_G,  
} .f}I$ "2  
else SG~R!kN}Q  
{ e\89;)  
for(int i=0;i<nStartPos.length;i++) ()rDM@  
{ V;m3=k0U  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); V
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} ,FTF@h-Cs  
for(int i=0;i<nEndPos.length-1;i++) T<OLf
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{ `27? f$,  
nEndPos = nStartPos[i+1]; dG| iA]  
} CB~&!MdMr  
nEndPos[nEndPos.length-1] = nFileLength; Uz0mSfBp  
} i@2?5U>h  
} W46sKD;\^W  
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//启动子线程 =$m|M m[a  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; mBNa;6w?{*  
for(int i=0;i<nStartPos.length;i++) S4Rv6{r:  
{ $o
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9+L! A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 6)TFb,  
nStartPos,nEndPos,i); QoqdPk#1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); '{J!5x?L^  
fileSplitterFetch.start(); ?znSA >  
} <_
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ON=xn|b4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); _+UD>u{  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4Q$\hO3b  
nEndPos = " + nFileLength); [P[syi#]t  
// fileSplitterFetch[nPos.length-1].start(); $N+azal+y  
6Up,B=sX0  
uy B ?-Y+  
//等待子线程结束 2LgRgY{Bl  
//int count = 0; b2Ct^`|M5  
//是否结束while循环 iKDGYM  
boolean breakWhile = false; rtY0?  
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s,0,w--=  
while(!bStop) 7)[4|I  
{ 0BD3~Lv  
write_nPos(); #j@Su )+  
Utility.sleep(500); u%&zY97/  
breakWhile = true; Xh){W~-  
|vzGFfRI  
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for(int i=0;i<nStartPos.length;i++) 27;*6/>,  
{ {+Eq{8m`  
if(!fileSplitterFetch.bDownOver) #.) qQ8*(  
{ Y(<>[8S m  
breakWhile = false; xHI>CNC,  
break; K^9!Qp  
} [Q)lJTs  
} #SQFI;zj  
if(breakWhile) Nk]r2^.z[  
break; Ww@Rewo  
.4U::j}  
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//count++; pi+m`O   
//if(count>4) C7,Ol0`v  
// siteStop(); LR}b^QU7  
} =eYrz@,  
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System.err.println("文件下载结束！"); RBiDU}j  
} d&t|Y:,8  
catch(Exception e){e.printStackTrace ();} Nf
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} h@/c76}f6p  
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//获得文件长度 KI#),~nS  
public long getFileSize() lY0^Z  
{ #O qfyY!  
int nFileLength = -1; 8D)2/$NsY}  
try{ #~ UG9@a  
URL url = new URL(siteInfoBean.getSSiteURL()); ;L++H5Kz6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :Q"]W!kCs  
httpConnection.setRequestProperty("User-Agent","NetFox"); BY72fy#e  
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int responseCode=httpConnection.getResponseCode(); (Z;-u+ }.  
if(responseCode>=400) Tw);`&Ulo  
{ UC3?XoT\  
processErrorCode(responseCode); ;)~loa1\  
return -2; //-2 represent access is error b\F(.8  
} O8r9&Nv  
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RL SP?o2J  
String sHeader; Z@=#ry  
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for(int i=1;;i++) xm6cn\
e  
{ he;&KzEu  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); sTU`@}}  
//Utility.log(in.readLine()); 7lqj"
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sHeader=httpConnection.getHeaderFieldKey(i); %70sS].@  
if(sHeader!=null) ehPrxIyC  
{ &+u) +<&;(  
if(sHeader.equals("Content-Length")) ^?VYE26  
{ S9U,so?  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); D4?5%s  
break; CfNHv-jDL  
} }PTYNidlR  
} dd@qk`Zl&A  
else 4N|^Joi  
break; !'Q/9%g  
} 3.Oc8(N^}  
} }Zu>?U  
catch(IOException e){e.printStackTrace ();} R_e{H^pY^  
catch(Exception e){e.printStackTrace ();} !ZPa
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Utility.log(nFileLength); ,|,DXw  
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return nFileLength; NguJ[  
} gNY}`'~hr  
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//保存下载信息（文件指针位置） K4b# y~@  
private void write_nPos() Av:5v3%  
{ po~V{>fUm  
try{ NHG+l)y:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); wg\*FfQn  
output.writeInt(nStartPos.length); #Cks&[!c  
for(int i=0;i<nStartPos.length;i++) -'*\KA@u  
{ cLj@+?/
 
// output.writeLong(nPos); 484lB}H  
output.writeLong(fileSplitterFetch.nStartPos); >DeG//rv
 
output.writeLong(fileSplitterFetch.nEndPos); 5RCZv\Wd&  
} _-$O6eZ  
output.close(); :oh(M|;/2  
} l=G=J(G  
catch(IOException e){e.printStackTrace ();} b1Bu5%bt,:  
catch(Exception e){e.printStackTrace ();} JDrh-6Zgj  
} Ch8w_Jf1yx  
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//读取保存的下载信息（文件指针位置） P[6@1  
private void read_nPos() d5mhk[p7\J  
{ y1z<{'2x  
try{ W&23M26"{  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); G?e"A0,  
int nCount = input.readInt(); @|kBc.(]  
nStartPos = new long[nCount]; -S5M>W.Qb{  
nEndPos = new long[nCount]; <+ 0cQq=2  
for(int i=0;i<nStartPos.length;i++) T7`9[  
{ h$7rEs  
nStartPos = input.readLong(); wmbjL=f Ia  
nEndPos = input.readLong(); tr3Rn :0]  
} 6z3 Yq{1  
input.close(); )2t!= ua  
} aN9#ATE  
catch(IOException e){e.printStackTrace ();} DtkY;Yl  
catch(Exception e){e.printStackTrace ();}
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} JRQ{Q"`)  
%%
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private void processErrorCode(int nErrorCode) J!r,ktO^U?  
{ Qx{k_ye`  
System.err.println("Error Code : " + nErrorCode); F^& Rg  
} 2D|2/ >[  
U(#)[S,  
F&?55@b  
//停止文件下载 e45gjjts  
public void siteStop() +c&n7  
{ @pq#?  
bStop = true; Ckd=tvL  
for(int i=0;i<nStartPos.length;i++) V/w:^@5+p  
fileSplitterFetch.splitterStop(); f4.k%|
]  
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}
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} 4u}"ng   
//负责部分文件的抓取 Kj
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**FileSplitterFetch.java [^wEKRt&  
*/ I,4t;4;Zk  
package NetFox; &' ,A2iG  
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import java.io.*; &0B<iO<f  
import java.net.*; !e~Yp0gX#  
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public class FileSplitterFetch extends Thread { l#7].-/  
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String sURL; //File URL f8]Qn8  
long nStartPos; //File Snippet Start Position  LW?Zd=  
long nEndPos; //File Snippet End Position Lg[v-b=?I  
int nThreadID; //Thread's ID !N5+.E0j  
boolean bDownOver = false; //Downing is over kOfq6[JC
 
boolean bStop = false; //Stop identical zqEMR>px  
FileAccessI fileAccessI = null; //File Access interface $HjKELoJ<  
HN'r ZAZ(  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >dH5n$Gb  
{ 1d49z9F  
this.sURL = sURL; Izrf42 >k  
this.nStartPos = nStart;
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this.nEndPos = nEnd; V,,/}f'  
nThreadID = id; ]W,K}~!
 
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ">b~k;M?  
} $`q8-+{  
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1_JxDT,=>  
public void run() ]7WBoC8  
{  ESOuDD2<  
while(nStartPos < nEndPos && !bStop)  y w"Tw  
{ Qxds]5WB/  
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Y.$InQ gL  
try{ W":is"  
URL url = new URL(sURL); [BS3y`c  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w, 0tY=h6  
httpConnection.setRequestProperty("User-Agent","NetFox"); YJgw%UVJ5m  
String sProperty = "bytes="+nStartPos+"-"; dZ!Wj7K)  
httpConnection.setRequestProperty("RANGE",sProperty); Qy ; M:q  
Utility.log(sProperty); jE)&`yZ5  
v4L#^Jw(^p  
%hK?\Pg3=E  
InputStream input = httpConnection.getInputStream(); &s!"pEZWck  
//logResponseHead(httpConnection); )c@I|L  
w>I>9O}(`  
\GtZX!0  
byte[] b = new byte[1024]; 9IL#\:d1  
int nRead; H[o'j@0  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2G"mm(   
{ x&3!z[m@@  
nStartPos += fileAccessI.write(b,0,nRead); 3j.Ft*SV  
//if(nThreadID == 1) *AXu_^^  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); W38My j!  
} w<_.T#  
= PldXw0  
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Utility.log("Thread " + nThreadID + " is over!"); `gqBJi  
bDownOver = true; {+f@7^/i.  
//nPos = fileAccessI.write (b,0,nRead); -
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} /:>f$k4~h  
catch(Exception e){e.printStackTrace ();} dQ^>,(  
} IS7g{:}=p  
} h$ M+Yo+  
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//打印回应的头信息 %" $.2O@  
public void logResponseHead(HttpURLConnection con) AO;`k]0e  
{ UuxWP\~2  
for(int i=1;;i++) MxxYMR  
{ _jef{j  
String header=con.getHeaderFieldKey(i); 1rC8]M.N  
if(header!=null) Z~
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); ,oDZ:"
;  
Utility.log(header+" : "+con.getHeaderField(header)); WX 79V  
else -$;H_B+.  
break; yuswWc'  
} \~xsBPX+x  
} }.gDaxj  
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<(d^2-0  
public void splitterStop() U*/  
{ =b,$jCv<,5  
bStop = true; xN2M|E]  
} %x
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 AO;+XP=  
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} 9`.b   
ci
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/* 9R>A,x(
  
**FileAccess.java G#duZNBdc  
*//文件访问(定位，写) OjMDxG w  
package NetFox; abD55YJY  
import java.io.*; (0D0G-r:  
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:@_CQc*yB  
public class FileAccessI implements Serializable{ xi;SKv;p  
3X0^xUA6  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 H
) q9.Jg  
RandomAccessFile oSavedFile; 1$@k@*u\  
long nPos; VbBZ\`b  
w \0=L=J  
p`{<q -  
public FileAccessI() throws IOException Js^ADUy  
{ wi*Ke2YKP  
this("",0); .d8) *  
} 2c0eh-Gf  
),bdj+wr78  
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public FileAccessI(String sName,long nPos) throws IOException P;hjr;  
{ yKZ~ ^  
oSavedFile = new RandomAccessFile(sName,"rw"); BT d$n!'$n  
this.nPos = nPos; uT]
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oSavedFile.seek(nPos); v.r$]O  
} $6fHY\i#R  
}qV4]*+{  
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public synchronized int write(byte[] b,int nStart,int nLen) J9poqp@`MG  
{ ( }JX ]-  
int n = -1; e;rs!I!Yw  
try{ !nuXK  
oSavedFile.write(b,nStart,nLen); f=/S]o4/3  
n = nLen; lt,x(2  
} Bu!Gy8\  
catch(IOException e) qf
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{  Kn\Oj=4  
e.printStackTrace (); 1+#Vj#  
} dUjdQ  
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return n; .V/TVz!b  
} A FfgGO  
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} P.;B V",  
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/* ZV;
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**SiteInfoBean.java JvHJ*E   
*/ |:H[Y"$1;  
package NetFox; ;2dhue  
m?<C\&)6x  
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public class SiteInfoBean { p(0!TCBs  
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private String sSiteURL; //Site's URL I"@5=m5  
private String sFilePath; //Saved File's Path )QI]b4[  
private String sFileName; //Saved File's Name d(To)ly.  
private int nSplitter; //Count of Splited Downloading File 4|++0=#D$  
NaVZ)  
/6 P()Upe  
public SiteInfoBean() ;AG5WPI  
{//nSplitter的缺省值为5  d(v )SS  
//default value of nSplitter is 5 p(Qm\g<  
this("","","",5); &N
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} n$b/@hp$z  
kTC6fNj[  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Xv:<sX  
{ vhhsOga  
sSiteURL= sURL; ^'
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sFilePath = sPath; bR;H@Fdg?  
sFileName = sName; z@i
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this.nSplitter = nSpiltter; VK?,8Y  
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} TR:D  
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public String getSSiteURL() 5RlJybN"o  
{ ^PWZ1.T  
return sSiteURL; g7d)YUc  
} TH6g:YP`7  
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fNB*o={r|  
public void setSSiteURL(String value) wetkmd  
{ M}@^8  
sSiteURL = value; 0]NsT0M  
} 5IMh$!/uc  
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TXy*-<#vR  
public String getSFilePath() T8qG9)~3  
{ 44_n5vp,T  
return sFilePath; T]E$H, p  
} :.sK:W("v  
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public void setSFilePath(String value) 5Z;Py"%  
{ #UGbSOoCtn  
sFilePath = value; ?|8
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} QR^pu.k@  
-G*u2i_*  
u,'c:RMV  
public String getSFileName() e=_*
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{ qLPI^g,  
return sFileName; $]%k <|X  
} (D~mmffY1  
&=s{ +0  
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public void setSFileName(String value) L(X:=) !K0  
{ ~[,E i k  
sFileName = value; d5u,x.R  
} +/UInAM  
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n){\KIU/O  
public int getNSplitter() 57r\s8  
{ U>:p`@  
return nSplitter; '3<YZWS  
} c{&sf y  
9N-mIGJ
 

3 #jPQ[+  
public void setNSplitter(int nCount) eQYW>z'%,  
{ 8BWLi5R[  
nSplitter = nCount; u/hD9g~H7K  
} =P2T
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} uRUysLIw  
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\)LY_D:  
/* r)*KgGsk  
**Utility.java N(F9vZOs  
*/ Zb}=?fcL;@  
package NetFox; WRD^S:`BH  
WI~';dK2]  
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public class Utility { b%pLjvU  
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?K}/b[[0v  
public Utility() |ukEnjI`u  
{ Ak|jJ
 
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} T#h`BtET[  
u QCQ$  
//线程睡眠 KS%xo6k.  
public static void sleep(int nSecond) F#W'>WB
U  
{ Z=wLNmH  
try{ 9g "?`_  
Thread.sleep(nSecond); /SP^fB*y  
} o
3%Gc/6%  
catch(Exception e) 8<IOX  
{ `)K1[&  
e.printStackTrace (); )<jj O  
} C2bN<K  
} 'N'EC`R  
N{oD1%  
//日志 l
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public static void log(String sMsg) U%U%a,rA5s  
{ Fe`$mtPu.  
System.err.println(sMsg); u9}=g%TV  
} B ljZ&wZW  
uiO8F*,!&r  
CCQ<.iCU  
public static void log(int sMsg) NcFHvK  
{ :8\z 0  
System.err.println(sMsg); 2z&HT SI  
} u9sffX5x[J  
} ~eE2!/%9  
-:>Mi5/ s  
_fa2ntuS=f  
/* $Jx] FZDQ  
**TestMethod.java iv:[]o  
*/ >*k3D&  
package NetFox; M0 =K#/  
|a/"7B|?\  
53@*GXzE  
public class TestMethod { <5?.
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#!C/~"Y*`|  
public TestMethod() 4GeWo@8h  
{ ///xx/weblogic60b2_win.exe {N/(lB8  
try{ jQ(qaX&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); )t&j0`Yq  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 0ir]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); l<!?`V6}  
fileFetch.start(); {3@/@jO?  
} Rw=gg>\  
catch(Exception e){e.printStackTrace ();} i|y8n7c  
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+{4ziqYj  
} *Xn{{  
349W0>eOT  
UuzT*Y>  
public static void main(String[] args) gW$X8ECX  
{ 7[.aAGTZ;  
new TestMethod(); MCjf$pZN]  
} MXq+aS{  
} <`+U B<K  
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