http断点续传简单实现（java)

/* ~Y;Z5e=  
**SiteFileFetch.java &O
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*/ _PQk<QZ  
package NetFox; }
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import java.io.*; ^rO!-  
import java.net.*; 7AqbfLO  
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public class SiteFileFetch extends Thread { Q~n%c7  
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SiteInfoBean siteInfoBean = null; //文件信息Bean -G'3&L4 D  
long[] nStartPos; //开始位置 ]r%fAmj  
long[] nEndPos; //结束位置 I"QU{]|J  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ``@e7~F{  
long nFileLength; //文件长度 )>iPx.hVSS  
boolean bFirst = true; //是否第一次取文件 bj_/  
boolean bStop = false; //停止标志 Z.rhM[*+0C  
File tmpFile; //文件下载的临时信息 >z%WW&Z'  
DataOutputStream output; //输出到文件的输出流 ~BE=z:  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） |Ho} D~  
public SiteFileFetch(SiteInfoBean bean) throws IOException &' y}L'  
{ RSw;b.t7  
siteInfoBean = bean; g706*o)h  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); M"msLz  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @3U=kO(^+\  
if(tmpFile.exists ()) ?k@;,l :s  
{ MX+gc$Y O  
bFirst = false; ?(}~[  
read_nPos(); h&!$ `)  
} ^&c &5S}  
else ~fzuz'"^  
{ TN08,:k  
nStartPos = new long[bean.getNSplitter()]; "`4M4`'  
nEndPos = new long[bean.getNSplitter()]; ,% .)mf  
} H|MAbx 7  
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} NSR][h_  
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public void run()  H =&K_  
{ V^>< =DNE  
//获得文件长度 Hq?dqg'%~  
//分割文件 v0bP|h[t  
//实例FileSplitterFetch HV]u9nrt#  
//启动FileSplitterFetch线程 u
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//等待子线程返回 xK5~9StP  
try{ 7xO~v23oe  
if(bFirst) )YZx]6\l)  
{ n;:C{5  
nFileLength = getFileSize(); =rkW325O  
if(nFileLength == -1) g@>93j=cZU  
{ myd:"u,}9  
System.err.println("File Length is not known!"); nyOmNvZf  
} rd=+[:7L  
else if(nFileLength == -2) Gq%,'amf  
{ N0ef5J JM`  
System.err.println("File is not access!"); FJ{&R Ld  
} hx4c`fOs  
else X+N8r^&  
{ Im]6-#(9\|  
for(int i=0;i<nStartPos.length;i++) @~&^1%37)  
{ EN8xn9M?  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); D^U?!S&4~  
} U]9k,#  
for(int i=0;i<nEndPos.length-1;i++) 8KKhD$  
{ k 6i&NG6  
nEndPos = nStartPos[i+1]; KYl!Iw67d  
} x0%@u^BF  
nEndPos[nEndPos.length-1] = nFileLength; xX Dj4j,  
} [81q 0@  
} [F{P0({%?  
e nw*[D !  
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//启动子线程 g'2;///  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; F%O+w;J4  
for(int i=0;i<nStartPos.length;i++) ep*8*GmP  
{ FMWM:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), f9)0OHa  
nStartPos,nEndPos,i); 1xO-tIp/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YlR9 1LX  
fileSplitterFetch.start(); %u2",eHCB  
} {.e^1qE  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), sk3AwG;A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $s 'n]]Wq  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", gyT0h?xDt  
nEndPos = " + nFileLength); 1(e64w@  
// fileSplitterFetch[nPos.length-1].start(); =j{Kxnv  
b&AeIU}&  
M)H*$!x}>  
//等待子线程结束 ySF^^X$J  
//int count = 0; yW"[}Lh4  
//是否结束while循环 >Pvz5Hf/wW  
boolean breakWhile = false; ;krIuk-  
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while(!bStop) iqN?'8  
{ /Ba/gq0j  
write_nPos(); 1y,/|Y  
Utility.sleep(500); 3UUN@Tx  
breakWhile = true; "^Y zHq6  
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for(int i=0;i<nStartPos.length;i++) 7 y$a=+D i  
{ J@#rOOu  
if(!fileSplitterFetch.bDownOver) $\M];S=CY  
{ }02(Y!Gh  
breakWhile = false; Hxleh><c-  
break; ?I\,RiZkz^  
} %36@1l-N  
} Qd>\{$N  
if(breakWhile) /!`xqG#  
break; uf"(b"N0  
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H5o=nWQ6e  
//count++; ;kT~&.,y  
//if(count>4) 6
& 6|R3  
// siteStop(); wzBw5nf\  
} py'xBi6}v  
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System.err.println("文件下载结束！");
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} k+Z2)j"  
catch(Exception e){e.printStackTrace ();} !/=.~B  
} zJ@^Bw;A^@  
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//获得文件长度 QZ*gR#K]Sz  
public long getFileSize() cH+ ~|3  
{ hML-zZ  
int nFileLength = -1; 0Q)YZ2  
try{ k|U2Mp  
URL url = new URL(siteInfoBean.getSSiteURL()); !%.=35NS@E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); i6g=fx6j*  
httpConnection.setRequestProperty("User-Agent","NetFox"); v-/vj/4>  
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int responseCode=httpConnection.getResponseCode(); {w7/M]m-  
if(responseCode>=400) e*U6^Xex  
{ )V&hS5P=S  
processErrorCode(responseCode); 2(m#WK7>F  
return -2; //-2 represent access is error Wrh$`JC  
} u(\O@5a  
$g/h=w@  
n=|%
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String sHeader; i4nFjz  
(NN;1{DB8  
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for(int i=1;;i++) o$rF-?  
{ cLw|[!5:  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); U]@?[+I0]  
//Utility.log(in.readLine()); ,]]*
}4[r  
sHeader=httpConnection.getHeaderFieldKey(i); vu#Z
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if(sHeader!=null) qI${7  
{ JYv<QsD  
if(sHeader.equals("Content-Length")) PTqia!  
{ _ElG&hyp  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `!AI:c*3p1  
break; k+vfZ9bD(J  
} m/I
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} k[,0kP;  
else *ZxurbX#  
break; }r!hm?e  
} +-,iC
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} Vjw u:M  
catch(IOException e){e.printStackTrace ();} KHgn  
catch(Exception e){e.printStackTrace ();} 5;,h8vW  
"/mtuU3rt  
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Utility.log(nFileLength); S>S7\b'  
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return nFileLength; -4zV yW S<  
} L"n)fe$  
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//保存下载信息（文件指针位置） K1Uq`TJ  
private void write_nPos() L(sT/  
{ ;{q*  
try{ P.
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output = new DataOutputStream(new FileOutputStream(tmpFile)); ~QDM .5  
output.writeInt(nStartPos.length); C+[)^2M{  
for(int i=0;i<nStartPos.length;i++) aB?usVoS  
{ -
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// output.writeLong(nPos); #sDb611}#  
output.writeLong(fileSplitterFetch.nStartPos); qmt9J?$k  
output.writeLong(fileSplitterFetch.nEndPos); y@<2`h  
} VpSpj/\m)'  
output.close(); w( _42)v]g  
} ZfK[o{9>  
catch(IOException e){e.printStackTrace ();} !?/:p.  
catch(Exception e){e.printStackTrace ();} P^48]Kj7  
} 7 )rL<+  
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//读取保存的下载信息（文件指针位置） \"Y,1in#  
private void read_nPos() RjVmHhX
 
{ V)N{Fr)&  
try{ XmwAYf  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); u3GBAjPsIk  
int nCount = input.readInt(); D79:L:  
nStartPos = new long[nCount]; "WUS?Q  
nEndPos = new long[nCount]; m[74p  
for(int i=0;i<nStartPos.length;i++) %^vT7c>  
{ 6a9$VGInU  
nStartPos = input.readLong(); v8j3 K  
nEndPos = input.readLong(); TlRc8r|  
} (QJe-)0_y  
input.close(); rp{|{>'`.q  
} xLDD;Qm,  
catch(IOException e){e.printStackTrace ();} g\ vT7x  
catch(Exception e){e.printStackTrace ();} tiHR&v  
} q$mc{F($D  

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private void processErrorCode(int nErrorCode) G3%Ju=  
{ sA77*T  
System.err.println("Error Code : " + nErrorCode); j7k}!j_O{  
} +a1iZ bh  
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//停止文件下载 RZ xwr  
public void siteStop() =R|XFZ,  
{ %0N HU`j  
bStop = true; W ';X4e  
for(int i=0;i<nStartPos.length;i++) i>s  
fileSplitterFetch.splitterStop(); -p.\fvip  
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} e)g&q'O  
} n=vDEX:'  
//负责部分文件的抓取 *{!Y_FrL  
**FileSplitterFetch.java hW<v5
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*/ bAGKi.  
package NetFox; uMS+,dXy  
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import java.io.*; @2)nhW/z6  
import java.net.*; %dFJ'[jDL  
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public class FileSplitterFetch extends Thread {
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*_
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String sURL; //File URL 'in%Gii  
long nStartPos; //File Snippet Start Position v#d\YV{I  
long nEndPos; //File Snippet End Position UI+6\ 3  
int nThreadID; //Thread's ID O'mcN*  
boolean bDownOver = false; //Downing is over hEQyaDD;  
boolean bStop = false; //Stop identical ~<m^  
FileAccessI fileAccessI = null; //File Access interface .
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [eDrjf3m  
{ ExS5RV@v'  
this.sURL = sURL; VNHceH  
this.nStartPos = nStart;  JhFbze>  
this.nEndPos = nEnd; -}|L<~  
nThreadID = id; KBmOi  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 % D  
} +*]$PVAFA  
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public void run() ^H3N1eC,`F  
{ ?K>)bA&l'  
while(nStartPos < nEndPos && !bStop) 2@
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{ 49~d6
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try{ ERpAV-Zf  
URL url = new URL(sURL); Zj2 si  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t]$n~!  
httpConnection.setRequestProperty("User-Agent","NetFox"); [-])$~WfW  
String sProperty = "bytes="+nStartPos+"-"; w={q@. g%  
httpConnection.setRequestProperty("RANGE",sProperty); o@e/P;E  
Utility.log(sProperty); %N*[{j= ^  
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InputStream input = httpConnection.getInputStream(); g<W]NYm  
//logResponseHead(httpConnection); $nO~A7  
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byte[] b = new byte[1024];  AG@gOm  
int nRead; c>_ti+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Hd|[>4Z  
{ <l{oE?N  
nStartPos += fileAccessI.write(b,0,nRead); k&ci5MpN  
//if(nThreadID == 1)  ES~b f  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u
}[ a  
} q!y.cyL  
aDF@AS  
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Utility.log("Thread " + nThreadID + " is over!"); u2 s  
bDownOver = true; pAE (i7  
//nPos = fileAccessI.write (b,0,nRead); yV(#z2|  
} ]F4QZV
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catch(Exception e){e.printStackTrace ();} ,|:.0g[n  
} qzUiBwUi@  
} *#T: _  
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//打印回应的头信息 |nefg0`rk  
public void logResponseHead(HttpURLConnection con) Kjd3!%4mB  
{ Qr$'Q7  
for(int i=1;;i++) e*7O!Z=O  
{ &n6{wtBP  
String header=con.getHeaderFieldKey(i); Z<nNk.G  
if(header!=null)  J=` 8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); tO M$'0u  
Utility.log(header+" : "+con.getHeaderField(header)); ;llPM`)  
else J3e
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break; 4z0gyCAC A  
} .l1
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} ?+t;\  
ys9:";X;}  
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public void splitterStop() U>2KjZB  
{ 4$xVm,n|  
bStop = true; Nk7y2[  
} I%5vI}  
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} u cpU$+  
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/* Bl b#h  
**FileAccess.java \l GD8@,x  
*//文件访问(定位，写) sFpg  
package NetFox; Kb%Y
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import java.io.*; =XR~
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MB)<@.A0  
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public class FileAccessI implements Serializable{ Tbi?AJa}  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \CjJa(vV  
RandomAccessFile oSavedFile; w}3N!jNDv  
long nPos; !Cr3>tA  
:^)?AO#J  
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public FileAccessI() throws IOException 5P!ZG
bG  
{ +e{ui +  
this("",0); fd'kv  
} +``vnC  
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public FileAccessI(String sName,long nPos) throws IOException 6Z_V,LD9L  
{ a|t~&\@  
oSavedFile = new RandomAccessFile(sName,"rw");  /a1uG]Mt  
this.nPos = nPos; w%])  
oSavedFile.seek(nPos); <
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} d5'Q1"{  
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public synchronized int write(byte[] b,int nStart,int nLen) Qt.*Z;Gs  
{ s5*4<VxQN.  
int n = -1; `%Ih'(ne  
try{ VIAq$iu7  
oSavedFile.write(b,nStart,nLen); EH844k8 p  
n = nLen; =8]`-(  
} ~0PzRS^o  
catch(IOException e) ~5P9^`KNH  
{ }097[-g7  
e.printStackTrace (); v`|]57?A  
} h@ lz  
cEL:5*cAU}  
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return n; Mq0MtC6-  
} ._rPM>B?  
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} 0F)v9EK(W4  
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/* w9|x{B  
**SiteInfoBean.java );!ND%  
*/ \TP$2i%W  
package NetFox; Q:P)g#suc  
%6Gg&Y$j!  
_HwA%=>7  
public class SiteInfoBean { c6:uM1V{  
IHEbT   
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private String sSiteURL; //Site's URL >w.;A%|N  
private String sFilePath; //Saved File's Path VP1hocW  
private String sFileName; //Saved File's Name _mm(W=KiL  
private int nSplitter; //Count of Splited Downloading File yY8zT
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KYiJXE[Q-  
public SiteInfoBean() 9QU\J0c/  
{//nSplitter的缺省值为5 : #a  
//default value of nSplitter is 5 ZxtO.U2  
this("","","",5); YrL(4Nt8  
} UBL{3s^"  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *}]#E$  
{ ;.4y@?B  
sSiteURL= sURL; 6Q:Wo)^!  
sFilePath = sPath; q(n"r0)=  
sFileName = sName; `NtW+v  
this.nSplitter = nSpiltter; ST{Vi';}  
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} dfFw6R  
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public String getSSiteURL() Tx}Nr^  
{ r)gK5Mv  
return sSiteURL; y,:WLk~  
} HGYTh"R  
>az~0PeEL  
1{N+B#*<[X  
public void setSSiteURL(String value) .2%t3ul[  
{ =AO (  
sSiteURL = value; ]njNSn  
} mh8fJ6j29N  
(7qlp*8.s  
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public String getSFilePath() # `^nmC/F  
{ 3@":&  
return sFilePath; ,P9F*;Dj  
} o-bH3Jkb]&  
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public void setSFilePath(String value) L(|K{vHh]  
{ 1Le8W)J  
sFilePath = value; gnH{_  
} VzXVy)d  
4FzTf7h^  
,\i*vJ#f  
public String getSFileName() X$UK;O  
{ ?3~t%Q`  
return sFileName; j4;^5 Dy^  
} "73*0'm  
jSpj6:@B  
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public void setSFileName(String value) s?HK2b^;D  
{ FO/cEu  
sFileName = value; z%E(o%l8  
} Tw';;euw  
&.E/%pQ`  
AO8 #l YP?  
public int getNSplitter() c>$d!IKCL  
{ ?1L<VL=b  
return nSplitter; nFJW\B&(`  
} 2,:{ 5]Q$  
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{#kCqjWG  
public void setNSplitter(int nCount) I3 "6"  
{ z]9t 5I  
nSplitter = nCount; <( OHX3~  
} E2M<I;:EA  
} Q
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/* Stwg[K0<  
**Utility.java R[zN?  
*/ ueJ^Q,-t  
package NetFox; Ug+ K:YUq  
$,K@xq5  
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public class Utility { q;#AlquY@  
;SE*En  
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public Utility() 'o)Y!VYnJF  
{  el2Wk@*  
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} 7C'@g)@^/  
__eB 7]#E  
//线程睡眠 wb9(aS4  
public static void sleep(int nSecond) dDA8IW![S  
{ Pd+*syOM  
try{ ^oav-R&  
Thread.sleep(nSecond); z00X ?F  
} ~IYR&GEaUG  
catch(Exception e) {XIpHr  
{ X'b3CS4  
e.printStackTrace (); cO]w*Hti  
} rmggP(  
} 2pmj*Y3"8  
K&&T:'=/  
//日志 3ibQbk  
public static void log(String sMsg) F5X9)9S  
{ : jkO  
System.err.println(sMsg); G>"n6v'^d  
} vLxaZWr  
5/Qu5/  
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public static void log(int sMsg) rrz([2E2  
{ l7uTk5  
System.err.println(sMsg); @k{q[6c2n  
} 9n is8  
} )PvnB=wy  
7 q!==P=  
$
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/* 7zx xO|p[  
**TestMethod.java Ej)7
[  
*/ 3|!3R'g/ >  
package NetFox; EC5= 2w<  

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public class TestMethod { }j2;B 8j  
>d`GNE  
t]0DT_iE  
public TestMethod() OIj.K@Kr  
{ ///xx/weblogic60b2_win.exe Y!45Kio  
try{ _IdW5G  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2FaCrc/  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); vE,^K6q0`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); hBRi5&%  
fileFetch.start(); L754odc  
} ;6 W[%{  
catch(Exception e){e.printStackTrace ();} Csy$1;"A  
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F?tWx+N<{  
} q6rkp f,Tl  
,+IFV  
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public static void main(String[] args) FR
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{ u=Ik&^v Wq  
new TestMethod(); ,\iXZ5"R  
} )#z{P[
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} 7b08Lo7b  
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