http断点续传简单实现（java)

/* 3gmu-tv  
**SiteFileFetch.java i+.bR.WO  
*/ qUp DmH  
package NetFox; 5 %aT  
import java.io.*; UbV} !  
import java.net.*; Bbx.RL.V  
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public class SiteFileFetch extends Thread { 1Xu^pc  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ag$UNV  
long[] nStartPos; //开始位置 lV!@h}mG  
long[] nEndPos; //结束位置 $f<Rj/`&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 w-MnJ(r  
long nFileLength; //文件长度 %!1:BQ,p,i  
boolean bFirst = true; //是否第一次取文件 +EgQj*F*  
boolean bStop = false; //停止标志 !~k-Sexh  
File tmpFile; //文件下载的临时信息 niN$!k+Jr  
DataOutputStream output; //输出到文件的输出流 )Ikx0vDFQ  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） >U$,/_uMNW  
public SiteFileFetch(SiteInfoBean bean) throws IOException [&FWR  
{ M0%):P?x  
siteInfoBean = bean; xpVYNS{c+|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); $ V"7UA22  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ojd/%@+u+Y  
if(tmpFile.exists ()) R|AGN*.  
{ 4E& 3{hnp  
bFirst = false; PDssEb7  
read_nPos(); H\<C@OkJS}  
} nZM|8  
else N~ XzgI  
{ nPUq+cXy]C  
nStartPos = new long[bean.getNSplitter()]; {*%'vVv+  
nEndPos = new long[bean.getNSplitter()];  0$l D  
} /z+}xRS  
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} ;dYpdy  
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public void run() ?<slB>8  
{ e&u HU8k*  
//获得文件长度 %+9Mr ami  
//分割文件 2FS,B\d  
//实例FileSplitterFetch ;wz YZ5=Di  
//启动FileSplitterFetch线程 l$Y7CIH  
//等待子线程返回 %-:6#bz  
try{ 8P'>%G<m  
if(bFirst) Piz/vH6M}  
{ d+fig{<b  
nFileLength = getFileSize(); 2,<!l(X  
if(nFileLength == -1) =GjxqIv  
{ . \fzK  
System.err.println("File Length is not known!"); TlZ|E '_C  
}
\
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else if(nFileLength == -2) -U=bC   
{ mOyBSOad4  
System.err.println("File is not access!"); R28h%KN  
} BfF$  
else F/}PN1#T  
{ jfHVXu^M  
for(int i=0;i<nStartPos.length;i++) h
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{ =2{^qvP  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); D{/GjFO  
} P$D1kcCw  
for(int i=0;i<nEndPos.length-1;i++) %c(':vI#  
{ hun/H4f|  
nEndPos = nStartPos[i+1]; l23#"gGb  
} K$\]\qG6  
nEndPos[nEndPos.length-1] = nFileLength; VHB5
 
} A=|&N%lP'  
} O&irgc!  
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1NT@}j~/  
//启动子线程 z/N~HSh!d  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 5o2;26c  
for(int i=0;i<nStartPos.length;i++) f|_iHY  
{ Ssr P  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6546"sU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;e_n7>'#%  
nStartPos,nEndPos,i); ^'C1VQ%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ; eq^m,oz  
fileSplitterFetch.start(); t8 #&bUX  
} }S
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !B(6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); m4|9p{E  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", A3bE3Fk$  
nEndPos = " + nFileLength); !["WnF{5eC  
// fileSplitterFetch[nPos.length-1].start(); H{`S/>)[   
m>?OjA!  
2bfKD'!aH  
//等待子线程结束 4?,N;Q  
//int count = 0; +=^10D  
//是否结束while循环 a4L8MgF&$-  
boolean breakWhile = false; $v+Q~\'  
L*1C2EL/q  
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while(!bStop) =\?KC)F*e  
{ BD9W-mF  
write_nPos(); {(AYs*5  
Utility.sleep(500); 'ac %]}`-  
breakWhile = true; M"#xjP.  
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for(int i=0;i<nStartPos.length;i++) x(&o=Pu  
{ ZPY#<^WOzr  
if(!fileSplitterFetch.bDownOver) _CBG?  
{ [L"(flY(E  
breakWhile = false; SI)u@3hl&w  
break; HkD6aJ:kA!  
} }i./,  
} NI\jGR.  
if(breakWhile) ,D3?N2mB  
break; mHUQtGAVQ  
Pp6(7j  
%<DXM`Y  
//count++; vu;pILN  
//if(count>4) -S OP8G  
// siteStop(); P|_>M SO1'  
} !&Vp5]c  
 [ K;3Qf)  
lh&Q{t(+8  
System.err.println("文件下载结束！"); M;,Q8z%  
} ]i)m   
catch(Exception e){e.printStackTrace ();} ,n}X,#]  
} xg k~y,F  
lphQZ{8  
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//获得文件长度 OW
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public long getFileSize() gh|TlvnA  
{ m@R!
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int nFileLength = -1; )Y+n4UL3NK  
try{ X<m#:0iD  
URL url = new URL(siteInfoBean.getSSiteURL()); [*Nuw_l  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); VChNDHiH  
httpConnection.setRequestProperty("User-Agent","NetFox"); )"2)r{7:  
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int responseCode=httpConnection.getResponseCode(); Lf{9=;  
if(responseCode>=400) /mX/ "~  
{ _$]3&P  
processErrorCode(responseCode); ] hGU.C"(  
return -2; //-2 represent access is error nxkbI:+t  
} d:.S]OI0  
x}$SB%9/  
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String sHeader; ) RS*MEgA  
qI"Xh" c?  
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for(int i=1;;i++) Stq&^S\x69  
{ qR/~a  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); DpH+lpC  
//Utility.log(in.readLine()); \3LP@;Phn  
sHeader=httpConnection.getHeaderFieldKey(i); `+[Ct08  
if(sHeader!=null) Z1 %"w*U  
{ $'}rBPA/  
if(sHeader.equals("Content-Length")) -'r4@='6}  
{ :3J,t//c  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); @9lV~,,U  
break; 9AO`Zk{/Ez  
} &#^^UT(nj  
} /]zn8d  
else S<H2e{~  
break; ^pruQp1X  
} jT>G8}h  
} byoP1F%  
catch(IOException e){e.printStackTrace ();} v% 6uU  
catch(Exception e){e.printStackTrace ();} 3DRJl,v  
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m r"b/oM{  
Utility.log(nFileLength); Z:9xf:g*  
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return nFileLength; Oo^kV:.)  
} MwbXZb{#"=  
<ZO"0oz%  
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//保存下载信息（文件指针位置） 5]pvHc  
private void write_nPos() #@FMH*?xX6  
{ Z0HfrK#oU  
try{ =?]H`T:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); BdBwfH%:  
output.writeInt(nStartPos.length); @yp#k
>  
for(int i=0;i<nStartPos.length;i++) L/\s~*:M  
{ ])F*)U  
// output.writeLong(nPos); *?bOH5$@Nw  
output.writeLong(fileSplitterFetch.nStartPos); >G7dw1;  
output.writeLong(fileSplitterFetch.nEndPos); E/[>#%@i  
} q@k/"ee*?  
output.close(); }z%fQbw  
} tQ=3Oa[u  
catch(IOException e){e.printStackTrace ();} 'EzKu~*  
catch(Exception e){e.printStackTrace ();} 'KvSI=$  
} prtNfwJz1j  
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//读取保存的下载信息（文件指针位置） |H-%F?<{  
private void read_nPos() a',6WugIP  
{ OlRtVp1  
try{ !r\u,l^
  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >
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int nCount = input.readInt(); r@")MOGc  
nStartPos = new long[nCount]; (;\" K?  
nEndPos = new long[nCount]; 8Of.n7{  
for(int i=0;i<nStartPos.length;i++) vH1IVF"DS  
{ ^UU@7cSi|G  
nStartPos = input.readLong(); B xAyjA6  
nEndPos = input.readLong(); {A^3<=|  
} Td,2.YMQ  
input.close(); NM FgCL  
} uuHg=8(  
catch(IOException e){e.printStackTrace ();} EzII!0 F  
catch(Exception e){e.printStackTrace ();} 0?V{u`*  
} 0zQ~'x  
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private void processErrorCode(int nErrorCode) N+lhztYQ?  
{ DVJuX~'|!  
System.err.println("Error Code : " + nErrorCode); gq%U5J"x;J  
} ?D>%+rK8c  

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i~Qnw-^B  
//停止文件下载 UHyGW$B  
public void siteStop() qa-%j+  
{ \ -n&z;`  
bStop = true; z }3`9  
for(int i=0;i<nStartPos.length;i++) t@X{qm:%Z  
fileSplitterFetch.splitterStop(); 8'WoG]E_  
r+=%Ag  
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} ?)NgODU  
} [0bp1S~  
//负责部分文件的抓取 ._%8H  
**FileSplitterFetch.java n4XEyCrD  
*/ ;t~Y>,  
package NetFox; "2 \},o9  
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, wXixf2  
import java.io.*; H0(.p'eN  
import java.net.*; ^O0trM>h-  
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public class FileSplitterFetch extends Thread { hZIbN9)8A  
L;\f^v(  
]ZR}Pm/CA  
String sURL; //File URL dzk1!yy  
long nStartPos; //File Snippet Start Position /07iQcT(  
long nEndPos; //File Snippet End Position mX2X.ww(4  
int nThreadID; //Thread's ID jXPf}{^  
boolean bDownOver = false; //Downing is over -,186ZVZ  
boolean bStop = false; //Stop identical 4 :phq  
FileAccessI fileAccessI = null; //File Access interface -M6#,Ji  
/+wCx#!  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException }!uwWBw`  
{ Gq=tR`.  
this.sURL = sURL; !L[$t~z  
this.nStartPos = nStart; 8B?*?,n5  
this.nEndPos = nEnd; %45*DT  
nThreadID = id; %E8HLTEvl  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~@#s<a,%;  
} j'x@P+A  
-!lSk?l  
I*z|_}$  
public void run() 8\F|{vt#  
{ i);BTwW)#]  
while(nStartPos < nEndPos && !bStop) uS<
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{ qWU59:d^{  
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try{ QVF561Yz  
URL url = new URL(sURL); yi8AzUW cW  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); fBb:J+  
httpConnection.setRequestProperty("User-Agent","NetFox"); !k<k]^Z\  
String sProperty = "bytes="+nStartPos+"-"; vYybQ&E/  
httpConnection.setRequestProperty("RANGE",sProperty); FwE<_hq//  
Utility.log(sProperty); v4qpE!W27~  
:x,dYJm  
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InputStream input = httpConnection.getInputStream(); Bx/)Sl@  
//logResponseHead(httpConnection); ], IQ~  
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byte[] b = new byte[1024]; y*Gq VA[  
int nRead; ^V~^[Yp  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) R5i xG9  
{ _'|C-j`u$  
nStartPos += fileAccessI.write(b,0,nRead); *V_b/Vt  
//if(nThreadID == 1) ef@F!s_fI  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +4n}H}9l  
} >]HvXEdNZ|  
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Utility.log("Thread " + nThreadID + " is over!"); R2==<"gq  
bDownOver = true; dy~M5,zn  
//nPos = fileAccessI.write (b,0,nRead); } rX)A\ g6  
} (&=3Y8  
catch(Exception e){e.printStackTrace ();} 4Wu(Tps  
} DoNN
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} HJ!!"  
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//打印回应的头信息 de9e7.(2  
public void logResponseHead(HttpURLConnection con) zjTCq; G  
{ peew<SX  
for(int i=1;;i++) WOeG3j
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{ (Z0.H3  
String header=con.getHeaderFieldKey(i); 9e7):ZupO  
if(header!=null) 8lyNg w1  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); FzOlM-)m   
Utility.log(header+" : "+con.getHeaderField(header)); v8 II=9  
else I* PxQ  
break; Uw?25+[b  
} 7:zoF],s  
} &p+2Vz{  
*'BI=*`  
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public void splitterStop() q&&uX-ez5W  
{  T4J WZ  
bStop = true; N3V4Mpf  
} ]M 2n%9  
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} #'m#Q6`  
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/* XM3~]  
**FileAccess.java (SCZ.G(>  
*//文件访问(定位，写) @.=2*e.z|b  
package NetFox; VrKLEN\  
import java.io.*; MH]?:]K9V  
'X\C/8\
 
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public class FileAccessI implements Serializable{ P@<K&S+f  
.G}$jO}  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 vos-[$  
RandomAccessFile oSavedFile; ZSB;4 ?:h  
long nPos; fc<,
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public FileAccessI() throws IOException ]'vAeC6{  
{ )"Wy/P  
this("",0); H:t2;Z'  
} t4p-pH'9b  
"/x/]Qx2  
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public FileAccessI(String sName,long nPos) throws IOException dCWq~[[  
{ T2to!*T  
oSavedFile = new RandomAccessFile(sName,"rw"); _AiGD  
this.nPos = nPos; >p3S,2SM  
oSavedFile.seek(nPos); h2aO-y>K  
}
?#:!!.I:  
L(/wsw~y*  
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public synchronized int write(byte[] b,int nStart,int nLen) (#Xgfb"S3  
{ TrVQ]9;jWk  
int n = -1; 6f J5Y iQ  
try{ OSK:Cb.-?F  
oSavedFile.write(b,nStart,nLen); Zf?jnDA  
n = nLen; '1lz`CAB+  
} /pp;3JPf  
catch(IOException e) s ~i,R  
{ 6a6N$v"  
e.printStackTrace (); ]2z Gb5s"  
} NV^n}]ci  
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1!R:}r3t  
return n; QjsN7h&%  
} pS!N<;OWr  
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} \qbEC.-K  
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/* 0[s<!k9=  
**SiteInfoBean.java ibgF,N  
*/ z.:IUm{z  
package NetFox; U}W7[f lc  
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h-@_.&P0e  
public class SiteInfoBean { a{iG0T.{Yh  
B 3eNvUFZg  
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private String sSiteURL; //Site's URL y|%lw%cSe  
private String sFilePath; //Saved File's Path 5dLb`Gf  
private String sFileName; //Saved File's Name Lw{'mtm  
private int nSplitter; //Count of Splited Downloading File HT
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v
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public SiteInfoBean() iu'rc/=V  
{//nSplitter的缺省值为5 84-7!< 6i  
//default value of nSplitter is 5 -axmfE?g0  
this("","","",5); SA6.g2pFz  
} j"<F?k@`Q  
[u8JqX  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) LMYO>]dg  
{ -GL-&^3IjH  
sSiteURL= sURL; f>+:UGmP  
sFilePath = sPath; oz?6$oE(bt  
sFileName = sName; zj'uKBDl  
this.nSplitter = nSpiltter; ;Z#DB$o\  
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S]DYEL$  
} g8;JpPw  
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public String getSSiteURL() j=w`%nh4"f  
{ 0bG2YMs  
return sSiteURL; yl~h `b4  
} 96CC5  
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public void setSSiteURL(String value) AlT04H
  
{ rxAb]~MMp  
sSiteURL = value; 1)h+xY  
} p"/B3  
*mXs(u  
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public String getSFilePath() #)$@Kvm  
{ t>%J3S>'ZV  
return sFilePath; '|K408i   
} <7sGA{  
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public void setSFilePath(String value) l050n9#9p  
{ . vQCX1V(  
sFilePath = value; j
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} cXvq=Rb  
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9!oNyqQ  
public String getSFileName() !`#xFRHe  
{ 'x!
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return sFileName; 421ol  
}
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public void setSFileName(String value) +eD+Z.{  
{ =`
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sFileName = value; #Y9~ Xp^.  
} u@-x3%W  
7q[a8rUdh  

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public int getNSplitter() 7{e*isV  
{ @s;qmBX4  
return nSplitter; Q'S"$^~{  
} k\a&4v  
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k),.  
public void setNSplitter(int nCount) J-g<-!>RM  
{ myeez+@ m  
nSplitter = nCount; Th)Z?\8zk  
} G\ht)7SGgf  
} ~1v5H]T{  
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+1%7*2q,  
/* YCd[s[  
**Utility.java UL.x*@o  
*/ 3Rsbi  
package NetFox; h|j
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public class Utility { jRP9e  
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public Utility() Q5H! ^RQm  
{ iFy_D  
/!mF,oR!  
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} >3a<#s{%  
(}u2) 9  
//线程睡眠 ]l WEdf+  
public static void sleep(int nSecond) _c4kj  
{ 93*MY7j}  
try{ (/r l\I  
Thread.sleep(nSecond); lU[" ZFP  
} O+^l>+ZGj?  
catch(Exception e) Gd8FXk,.!  
{ \'gb{JO  
e.printStackTrace (); *Jy'3o  
} ZYy?JDAO  
} |aovZ/b4  
:Ej#qYi  
//日志 W5^m[,GU'  
public static void log(String sMsg) w+NdEE4H9z  
{ MM*B.y~TxZ  
System.err.println(sMsg); .A. VOf_  
} "[rChso  
Hq*\,`b&  
vO#=]J8`  
public static void log(int sMsg) D!- 78h
 
{ dC7YVs_,#  
System.err.println(sMsg); $-}a<UFE;  
} .m]"lH*  
} %&RF;qa2xu  
`H.~#$  
}j/($,  
/* Ip0~  
**TestMethod.java <:mV^tK  
*/ %)$^_4.g  
package NetFox; =skw@c^  
ur
,!-t(~t  
{WE1^&Vk-}  
public class TestMethod { s^{hdCCl67  
9BJP|L%q  
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public TestMethod() &G)I|mv  
{ ///xx/weblogic60b2_win.exe ?~vVSY  
try{ 0GtL6M@pP  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^}+qd1r  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); iz&$q]P8  
SiteFileFetch fileFetch = new SiteFileFetch(bean); avmuI^LLs  
fileFetch.start(); S4m??B  
} L"|~,
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catch(Exception e){e.printStackTrace ();}  jIMT&5k  
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} sw={bUr6G`  
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public static void main(String[] args) i|]Kw9  
{ !\ IgTt,  
new TestMethod(); QUPZe~G>L  
} (aAv7kB&  
} {{G`0i2KV  
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