http断点续传简单实现（java)

/* uMBb=   
**SiteFileFetch.java dRTpG
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*/ Q1 vse  
package NetFox; 6:\z8fYD  
import java.io.*; [92bGR{  
import java.net.*; FRTvo  
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public class SiteFileFetch extends Thread { A3zNUad;  
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SiteInfoBean siteInfoBean = null; //文件信息Bean taOsC!Bp  
long[] nStartPos; //开始位置 ,I[A~  
long[] nEndPos; //结束位置 8\Eq(o}7  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 i4 tW8Il  
long nFileLength; //文件长度 5?|P
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boolean bFirst = true; //是否第一次取文件 .T*7nw  
boolean bStop = false; //停止标志 CY9`HQ1  
File tmpFile; //文件下载的临时信息 FD}>}fLv  
DataOutputStream output; //输出到文件的输出流 ..^,*  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） dk2o>jI4;  
public SiteFileFetch(SiteInfoBean bean) throws IOException SiJX5ydz  
{ v aaZ  
siteInfoBean = bean; upH%-)%'  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); '?!2h'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;"GI~p2~7  
if(tmpFile.exists ()) 4U:+iumy2  
{ Y'%_--  
bFirst = false; ^F1zkIE  
read_nPos(); :Ee5:S   
} fKT(.VNq5  
else GgjBLe=C  
{ @i:_JOl  
nStartPos = new long[bean.getNSplitter()]; VAR/
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nEndPos = new long[bean.getNSplitter()]; on1mu't_;  
} K#p&XIY,  
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} >:P3j<xTv  
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public void run() wwmODw<tT  
{ 1vxh3KS.  
//获得文件长度 (.
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//分割文件
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//实例FileSplitterFetch R:JS)>B  
//启动FileSplitterFetch线程 ( ]o6Pi  
//等待子线程返回 9/|i.2&  
try{ #Ryu`b  
if(bFirst) JXnPKAN  
{ c5rQkDW  
nFileLength = getFileSize(); IA;KEGJ  
if(nFileLength == -1) =
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{ ]QU52R@M  
System.err.println("File Length is not known!"); UoxF00H@!  
} s^{j  
else if(nFileLength == -2) Jq`fD~
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{ `0Q:d'  
System.err.println("File is not access!"); 7+u%]D!  
} ;7<a0HZ5!  
else j|(bDa
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{ ArU>./)Q  
for(int i=0;i<nStartPos.length;i++) BmUzsfD  
{ Xl*-A|:j  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ig/716r|  
}
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for(int i=0;i<nEndPos.length-1;i++) Sb[rSczS~  
{ @;,O V&XYn  
nEndPos = nStartPos[i+1]; 0+:.9*g=k  
} @]#+`pZ4A  
nEndPos[nEndPos.length-1] = nFileLength; ~K],hi^<P  
} 9e :E% 2  
} C127he  
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pN]Hp"v  
//启动子线程 2i(|?XJ^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; qc'tK6=jp  
for(int i=0;i<nStartPos.length;i++) v981nJ>w,  
{ a\m10Ih:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 25ZGuM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Da-(D<[0  
nStartPos,nEndPos,i); .Um%6a-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1I
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fileSplitterFetch.start(); ;+b}@e  
} v|,Hd  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), v V^GIWK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); q%:Jmi>  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", pmW=l/6+V3  
nEndPos = " + nFileLength); Ft.BfgJ$  
// fileSplitterFetch[nPos.length-1].start(); mQs'2Y6Oa  
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//等待子线程结束 q=1SP@;\6  
//int count = 0; e<^4F%jSK  
//是否结束while循环 kyo ,yD  
boolean breakWhile = false; V!U[N.&$  
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while(!bStop) 2aje$w-  
{ xf]4!zE  
write_nPos(); ia_8$>xW+  
Utility.sleep(500); VYAe!{[  
breakWhile = true; Xp?Z;$r$  
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for(int i=0;i<nStartPos.length;i++) T&23Pf1  
{ =W|Q0|U  
if(!fileSplitterFetch.bDownOver) 1aT$07G0  
{ d|NNIf  
breakWhile = false; d<3"$%C  
break; z"O-d<U5  
} e#OU {2X  
} [1UqMkXtf  
if(breakWhile) 6kuSkd$.  
break; $WPN.,7
  
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//count++; +{w&ksk  
//if(count>4) SA7,]&Zb  
// siteStop(); kv4J@  
} )nk>*oE  
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System.err.println("文件下载结束！"); E37@BfpO3  
} &L?Dogo  
catch(Exception e){e.printStackTrace ();} &sRJ'oc  
} 5~X%*_[],  
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M:SxAo-D2  
//获得文件长度 '} kq@  
public long getFileSize() ;i#gk%- 2  
{ ^,5.vfES  
int nFileLength = -1; ^9RBG#ud  
try{ _#F'rl6'  
URL url = new URL(siteInfoBean.getSSiteURL()); uR%H"f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <FK><aA_i*  
httpConnection.setRequestProperty("User-Agent","NetFox"); By_Ui6:D  
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int responseCode=httpConnection.getResponseCode(); R`&ioRWj  
if(responseCode>=400) J?<L8;$s
7  
{ u~kwNN9t3  
processErrorCode(responseCode); p{J_d,JH  
return -2; //-2 represent access is error E)E!  
} Ttj5%~  
rh_({rvQ  

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String sHeader; gZUy0`E  
;hvXFU  
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for(int i=1;;i++) 7GUJ&U)J  
{ ?:nZv< x  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !T~d5^l!  
//Utility.log(in.readLine()); 1W g8jr's  
sHeader=httpConnection.getHeaderFieldKey(i); %ze1ZWO{  
if(sHeader!=null) ezvaAhd{  
{ |Q;o538  
if(sHeader.equals("Content-Length")) GXRjR\Ch  
{ \d+HYLAJn  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); bH{aI:9Fb
 
break; c" 7pf T  
} gsp7N  
} 9-^p23.@[j  
else ftPw6  
break; QA(,K}z~^S  
} ^IpiNY/%Q  
} h'x~"k1  
catch(IOException e){e.printStackTrace ();} v1=X=H  
catch(Exception e){e.printStackTrace ();} bZXNo  
/<$"c"UQ  
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Utility.log(nFileLength); ,Tl5@RN  
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return nFileLength; n4 @a`lN5g  
} (<Xdj^v  
C(|5,P#5  
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//保存下载信息（文件指针位置） \xxVDr.  
private void write_nPos() i 8X
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{ '[
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try{ :gq@/COo(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); yp^*TD/J  
output.writeInt(nStartPos.length); `W n5 .V  
for(int i=0;i<nStartPos.length;i++) BfT,  
{ Zg&\K~OC  
// output.writeLong(nPos); d6EY'*0  
output.writeLong(fileSplitterFetch.nStartPos); Dj+Osh  
output.writeLong(fileSplitterFetch.nEndPos); &>l8SlC?  
} ef;L|b%pp  
output.close(); ~,68S^nP)H  
} @t8kN6.  
catch(IOException e){e.printStackTrace ();} O97bgj]  
catch(Exception e){e.printStackTrace ();} })lT fy  
} YXVJJd$U  
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//读取保存的下载信息（文件指针位置） Td1ba^J  
private void read_nPos() *v ^"4  
{ v|(b,J3  
try{ O + & xb  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -3tBN*0+  
int nCount = input.readInt(); QCf
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nStartPos = new long[nCount]; `;CU[Ps?]  
nEndPos = new long[nCount]; PX2k,%  
for(int i=0;i<nStartPos.length;i++) _D9@<+MS*  
{ XFTMT'9  
nStartPos = input.readLong(); vGwD~R  
nEndPos = input.readLong(); ;Ph)BY<  
} uO(guA,C  
input.close(); -==qMrKP  
} _|B&v  
catch(IOException e){e.printStackTrace ();} m`IQ+,e  
catch(Exception e){e.printStackTrace ();} gQ[^gPWP"  
} kO_XyC4(  
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private void processErrorCode(int nErrorCode) ;nKHm  
{ ;kW}'&Ug  
System.err.println("Error Code : " + nErrorCode); F ssEs!#  
} UX`DZb+^  
#6sC&w3  
-5v.1y=!L  
//停止文件下载 gQ=POJ=G  
public void siteStop() kj!7|1i2  
{ Au} ;z6k  
bStop = true; ^;$a_$|  
for(int i=0;i<nStartPos.length;i++) 4t Nvq  
fileSplitterFetch.splitterStop(); h+~df(S.  
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} h<1dTl*  
} Q!Ow{(|
 
//负责部分文件的抓取 ~po%GoH(K  
**FileSplitterFetch.java pJIE@Q|hi  
*/ _*ouo<x  
package NetFox; NTXL>Q*e  
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import java.io.*; ^I<T+X+<  
import java.net.*; MJK
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public class FileSplitterFetch extends Thread { #C1A5JE&  
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String sURL; //File URL )s<WG}  
long nStartPos; //File Snippet Start Position #} ~p^ 0  
long nEndPos; //File Snippet End Position ).}k6v[4)  
int nThreadID; //Thread's ID ,0uo&/Y4L  
boolean bDownOver = false; //Downing is over [AX"ne#M*  
boolean bStop = false; //Stop identical [TK? P0  
FileAccessI fileAccessI = null; //File Access interface +'['HQ)  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6{+_T  
{ P%+or*  
this.sURL = sURL; Wda\a.bXT  
this.nStartPos = nStart; P"9@8aLB  
this.nEndPos = nEnd; 0L0Jc,(F+  
nThreadID = id; ]LBvYjMY  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 @?3vRs}h  
} KT];SF^Y  
=Esbeb7P  
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public void run() z/0yO@_D/q  
{ }WO9!E(  
while(nStartPos < nEndPos && !bStop) WiNr866nB  
{ J[!x%8m  
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try{ 6I&j cHH  
URL url = new URL(sURL); +t>*l>[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); UOu
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httpConnection.setRequestProperty("User-Agent","NetFox"); Y$x"4=~  
String sProperty = "bytes="+nStartPos+"-"; R] Disljq  
httpConnection.setRequestProperty("RANGE",sProperty); KIKq9*  
Utility.log(sProperty); nEd M_JPv  
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InputStream input = httpConnection.getInputStream(); kQw
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//logResponseHead(httpConnection); +2EHmu
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byte[] b = new byte[1024]; eA1k)gjE  
int nRead; E5*-;
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 3V/_I<y  
{ }0BL0N`_  
nStartPos += fileAccessI.write(b,0,nRead); NqT1b
uU#  
//if(nThreadID == 1) ApG'jN  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); gHvW e  
} 8B*E+f0  
x/%7%_+'  
#.)xm(Ys  
Utility.log("Thread " + nThreadID + " is over!"); ]{|fYt_-  
bDownOver = true; "u<jbD  
//nPos = fileAccessI.write (b,0,nRead); /[Bl  
} }%!FMXe  
catch(Exception e){e.printStackTrace ();} V;iL[  
} JlC<MQ?  
} J[}gku?C;  
M)"]$TM  
!K3i-zY  
//打印回应的头信息 DYo<5^0  
public void logResponseHead(HttpURLConnection con) wi\z>'R  
{ Y
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for(int i=1;;i++) 068WlF cWV  
{ y _'eyR@)  
String header=con.getHeaderFieldKey(i); ;'=VrE6  
if(header!=null) X2\E9hJg  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); X)Dqeb6  
Utility.log(header+" : "+con.getHeaderField(header)); UsLh)#}h  
else "JzfL(yt  
break; /&D'V_Q`*  
} v#<\:|XAg  
} 2q"_^deI5*  
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public void splitterStop() 6Cl+KcJH  
{ s.^c..e75C  
bStop = true; *nYB o\@g  
} K4j@j}zK9I  
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} W *YW6  
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/* A#Xj]^-*  
**FileAccess.java D^,\cZbY  
*//文件访问(定位，写) M'\pkzx  
package NetFox; WYSck&9  
import java.io.*; T?H\&2CLT  
L3B8IDq  
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public class FileAccessI implements Serializable{ G$cxDGo  
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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 sL)Rg(rkx  
RandomAccessFile oSavedFile; 5{')GTdX>  
long nPos;

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i  
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public FileAccessI() throws IOException B^Xy0fq  
{ G3H#XK D  
this("",0); HjV\lcK:v  
} -&trk  
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public FileAccessI(String sName,long nPos) throws IOException M|U';2hZN:  
{ %v]7BV^%6  
oSavedFile = new RandomAccessFile(sName,"rw"); ER{yuw  
this.nPos = nPos; BwJNi6,  
oSavedFile.seek(nPos); IK8%Q(.c  
} L<0=giE  
(.PmDBW  
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public synchronized int write(byte[] b,int nStart,int nLen) +d=~LQ}*  
{ 2[.5oz`  
int n = -1; -<O JqB  
try{ )j\r,9<K+5  
oSavedFile.write(b,nStart,nLen); 9#u}^t  
n = nLen; {U(Bfe^a,  
} w]n4KR4  
catch(IOException e) .SG0}8gW  
{ #xlZU  
e.printStackTrace (); /[0F6  
} gC0;2  
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return n; NzAQ@E2d:  
} Hr8\QgD<4  
QS\Uq(Ja\  

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} SAP;9*f1\  
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/* 0X.TF  
**SiteInfoBean.java +hpSxdAz4  
*/ 0"TgLd  
package NetFox; Y7-*2"!  
4*iHw+%mq  
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public class SiteInfoBean { 0k%hY{  
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private String sSiteURL; //Site's URL ^ZR8s^X  
private String sFilePath; //Saved File's Path O"qR}W  
private String sFileName; //Saved File's Name 97!H`|u <  
private int nSplitter; //Count of Splited Downloading File R+s1[Z  
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public SiteInfoBean()
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{//nSplitter的缺省值为5 XYts8}y5  
//default value of nSplitter is 5 "i&fp:E0  
this("","","",5); |IAW{_9)U  
} +Jdm#n?_  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) +SyUWoM  
{ b]w[*<f?  
sSiteURL= sURL; 0:. 6rp  
sFilePath = sPath; ":V%(c  
sFileName = sName; B.}cB'|  
this.nSplitter = nSpiltter; V(r`.75  
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} -rO*7HO
 
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public String getSSiteURL() l/M[am  
{ 5E`JD  
return sSiteURL; ZEqE$:  
} Uh}+"h5  
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]  
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public void setSSiteURL(String value) \KCWYi]  
{ lr0M<5d=p  
sSiteURL = value; D!S8oKW  
} ^@K WYAAW5  
8]HY. $E  
%{U"EZ]D!  
public String getSFilePath() 5*Btb#:  
{ ?T <rt  
return sFilePath; ~~@y_e[N#l  
} =D5wqCT(Q  
|WBZN1W)  
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public void setSFilePath(String value) pu#[pa  
{ HJ",Sle  
sFilePath = value; =6
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} RbKwO} z$q  
#hy
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&*A:[b\  
public String getSFileName() \OT6L'l],  
{ $cu]_gu  
return sFileName; +X[8wUm|^  
} SwX@I6huM  
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public void setSFileName(String value) >9MS"t  
{ I3PQdAs~&h  
sFileName = value; Y0}4WWV  
} i(Vm!Y82  
7VY8CcL  
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public int getNSplitter() ,WGc7NN`  
{ %0zS  
return nSplitter; f7 wmw2  
} A$:|Qd7F1  
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!?b/-~o7S  
public void setNSplitter(int nCount) ki#bPgT  
{ )'t&q/Wn  
nSplitter = nCount; 5D L,U(Y  
} 8gAu7\p}  
} )P%4:P  
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/* hX3@f;[B2  
**Utility.java QvJZkGX  
*/ =|"=l1  
package NetFox; Z vRxi&Z{?  
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public class Utility { ,_bp)-OG  
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}#bZ8tm&  
public Utility() GMw)*  
{ *Dc@CmBr  
ol
}`Wwy  
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} fM2^MUp[=1  
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//线程睡眠 YXRjx.srf  
public static void sleep(int nSecond) WL:0R>0  
{ c 6q/X*  
try{ "koo` J  
Thread.sleep(nSecond); *6P
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} e=L*&X  
catch(Exception e) 0qR$J  
{ 59Nd}wPO;  
e.printStackTrace (); \447]<u  
} 8)?_{  
} #N9d$[R*  
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//日志 rs_h}+6"s  
public static void log(String sMsg) Pk:zfC?4  
{ ^vaL8+  
System.err.println(sMsg); 5k~\or 5_  
} 32^#RlSu8  
@,e8t BL  
#9,=Owup  
public static void log(int sMsg) \4QH/e  
{ B\0t&dai|'  
System.err.println(sMsg); Eu4 &-i  
} zi.mq&,]R  
} C`EY5"N r  
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/* MQ9vPgh  
**TestMethod.java Qi^;1&  
*/ NWaO_sm  
package NetFox; sv`"\3N[  
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public class TestMethod { {2EMz|&8  
o3\
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public TestMethod() yzg9I  
{ ///xx/weblogic60b2_win.exe y!hi"!  
try{ LuL$v+`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); q)k{W>O  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); *m&%vj.Kc  
SiteFileFetch fileFetch = new SiteFileFetch(bean); > Y]_K  
fileFetch.start(); \HD-vINV;  
} N%*9&FjrL  
catch(Exception e){e.printStackTrace ();} 1a*6ZGk.  
kC31$jMC3!  
H:{?3gk.P3  
} 0R4akLW0  
&~ y{'zoL  
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public static void main(String[] args) }H2#H7!H  
{ qy&\Xgn;GA  
new TestMethod(); J'Gm7h{   
} gi1j/j7  
} Oq}ip  
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