http断点续传简单实现（java)

/* cNX0.7Ls  
**SiteFileFetch.java QEavb
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*/ {x+"Ru~7,  
package NetFox; %|3I|'%Y  
import java.io.*; 4TBK:Vm5  
import java.net.*; q]-CTx$  
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public class SiteFileFetch extends Thread { .)7r /1o  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ^&AhWm7\  
long[] nStartPos; //开始位置 = }&@XRLJ  
long[] nEndPos; //结束位置 jL|y4  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 5,>Of~YN  
long nFileLength; //文件长度 \,w*K'B_Y  
boolean bFirst = true; //是否第一次取文件 Y\.ds%G  
boolean bStop = false; //停止标志 aXoD{zA  
File tmpFile; //文件下载的临时信息 ]kN<N0;\d  
DataOutputStream output; //输出到文件的输出流 bN,>,hj  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） hdw-gem{?  
public SiteFileFetch(SiteInfoBean bean) throws IOException
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{ YpAJ7E|7  
siteInfoBean = bean; ,~R`@5+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); d$3;o&VUNI  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); g1je':  
if(tmpFile.exists ()) |M*jo<C  
{ )YDuq(g&  
bFirst = false; RG'Ft]l92N  
read_nPos(); yzvNv]Z'*  
} fQ\nK H~  
else fkp
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{ p)t1]<,Of  
nStartPos = new long[bean.getNSplitter()]; D# $Fj  
nEndPos = new long[bean.getNSplitter()]; BZ]6W/0  
} {*=+g>RgD  
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} QFP3S(  
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public void run() @} nI$x.  
{ j|`6[93MG  
//获得文件长度 |Ef\B]Ns  
//分割文件 A9*( O)  
//实例FileSplitterFetch [j6EzMN  
//启动FileSplitterFetch线程 4Y):d!'b  
//等待子线程返回 yGNZw7^(  
try{ uCc.dluU  
if(bFirst) ;XJK*QDN  
{ Q}KNtNCpx  
nFileLength = getFileSize(); 5E~?hWAv  
if(nFileLength == -1) Dq#/Uw#  
{ sr0.4VU1  
System.err.println("File Length is not known!"); F{#m~4O  
} *K9I+t"g  
else if(nFileLength == -2) U4DQ+g(A  
{ S$CO T)7  
System.err.println("File is not access!"); z7[TgL7  
} >&@hm4  
else ~?V+^<P  
{ E8TJ*ZU  
for(int i=0;i<nStartPos.length;i++) 1v)X]nW  
{ xW$F-n  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9Tgl/}q)  
} [m9Pt]j@  
for(int i=0;i<nEndPos.length-1;i++) ]L'FYOfrpx  
{ /`M>3q[  
nEndPos = nStartPos[i+1]; hEO#uAR^Z  
} 4H7 3a5f  
nEndPos[nEndPos.length-1] = nFileLength; 9;Z2.P"w  
} dXkgWLI~  
} "4VC:"$f  
| HkLl^  
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//启动子线程 x=+R0ny  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; oYYns%r}{  
for(int i=0;i<nStartPos.length;i++) _
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{ =j)y.
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @S/PB[%S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), q|E0Y   
nStartPos,nEndPos,i); [x{S ,?6  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Z_Gb
9  
fileSplitterFetch.start(); w#?@ulr]d  
} /UJ@e  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $ae*3L>5M  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9n$0OH /q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", '64&'.{#>r  
nEndPos = " + nFileLength); >28.^\?H4  
// fileSplitterFetch[nPos.length-1].start(); 4$~]t:n  
RwH<JaL:  
|{#=#3X  
//等待子线程结束
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//int count = 0; .Y
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//是否结束while循环 }yCw|B|a  
boolean breakWhile = false; |E\0Rv{H3  
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while(!bStop) sZ,MNF8i  
{ _n.2'  
write_nPos(); "W_C%elg  
Utility.sleep(500); _1z|QC  
breakWhile = true; 4dDDi,)U  
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for(int i=0;i<nStartPos.length;i++) ^
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{ S.;>:Dd[K  
if(!fileSplitterFetch.bDownOver) 9m2_zfO[w  
{ >".,=u'  
breakWhile = false; l2
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break; )4d)G5{  
} r]x;JBy  
} hcQvL>  
if(breakWhile) 4<S*gu*W  
break; >*xa\ve  
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//count++; -+1it  
//if(count>4) Da)rzr|}>3  
// siteStop(); M@a?j<7P,m  
} s52c`+  
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System.err.println("文件下载结束！"); =*q|568  
} lVywc:X  
catch(Exception e){e.printStackTrace ();} 4\HB rd#P  
} h&7]Bp  
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55
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//获得文件长度 '1)BZ!  
public long getFileSize() -e=p*7']  
{ LGN,8v<W(  
int nFileLength = -1; /Kmzi9j+  
try{ (wmMHo|  
URL url = new URL(siteInfoBean.getSSiteURL()); X\SZ Q[gN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !GkwbHr+p  
httpConnection.setRequestProperty("User-Agent","NetFox"); im&E\`L7  
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int responseCode=httpConnection.getResponseCode(); B;'Dh<J1
 
if(responseCode>=400) 15Vb`Vf`N  
{ { 7y.0_Y
  
processErrorCode(responseCode); (7RxCo=X  
return -2; //-2 represent access is error 9I>+Q&   
} p*10u@,  
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String sHeader; IxT[1$e  
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for(int i=1;;i++) U;n$  
{ @%L4^ms  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); xq:.|{HUk  
//Utility.log(in.readLine()); DG8LoWZ  
sHeader=httpConnection.getHeaderFieldKey(i); !Gu,X'#Ab  
if(sHeader!=null) I__|+%oC  
{ v}hmI']yf  
if(sHeader.equals("Content-Length")) v*%#Fp,g8  
{ hd~X c  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); v\*43RL  
break; jsSxjf;O  
} qr%9Sdvx  
} "J]_B  
else BM*9d%m^  
break; #LlHsY530N  
} >:M3!6H_~{  
} R}F0_.  
catch(IOException e){e.printStackTrace ();} .op: 2y9]  
catch(Exception e){e.printStackTrace ();} hkw;W[ZWa  
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Utility.log(nFileLength); _Zya GDv  
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return nFileLength; JicAz1P1W  
} hXi^{ntw,  
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//保存下载信息（文件指针位置） $x5P5^Y  
private void write_nPos() s z  
{ 2wE?O^J  
try{ ]]{$X_0n  
output = new DataOutputStream(new FileOutputStream(tmpFile)); D3V5GQ\=  
output.writeInt(nStartPos.length); W B)
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for(int i=0;i<nStartPos.length;i++) WO W4c&  
{ FL!W oTB  
// output.writeLong(nPos); 5T;M,w6DV  
output.writeLong(fileSplitterFetch.nStartPos); ;cl\$TDL  
output.writeLong(fileSplitterFetch.nEndPos); _^Lv8a3(O  
} `_sc_Y|C!  
output.close(); R6HMi#eF  
} ?Y2ZqI  
catch(IOException e){e.printStackTrace ();} 9Vz1*4Ln  
catch(Exception e){e.printStackTrace ();} t4pc2b  
} Ddde,WJA  
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//读取保存的下载信息（文件指针位置） c%v[p8 %  
private void read_nPos() GHeJpS  
{ jr{C/B}  
try{ $$~
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !7!xJ&/V  
int nCount = input.readInt(); 8;;!2>N  
nStartPos = new long[nCount]; uZ( I|N$  
nEndPos = new long[nCount]; L+Yn}"gIs  
for(int i=0;i<nStartPos.length;i++) ]kq{9b';  
{ a'f"Zdh%w  
nStartPos = input.readLong(); . $uvQpyh  
nEndPos = input.readLong(); o^;$-O!/  
} ;T~]|#T\6  
input.close();
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} $.kP7!`:,  
catch(IOException e){e.printStackTrace ();} yC !`6$  
catch(Exception e){e.printStackTrace ();} wXp A1,i  
} IW3ZHmrpA  
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private void processErrorCode(int nErrorCode) 5bM/ v  
{ Zpg/T K  
System.err.println("Error Code : " + nErrorCode); -_Pd d[M  
} wEENN_w  
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//停止文件下载 "Wr5:T-;  
public void siteStop() c4ptY5R),  
{ $A"kHS7T  
bStop = true; KJ<7aZ
  
for(int i=0;i<nStartPos.length;i++) y0cHs|8  
fileSplitterFetch.splitterStop(); BJ!b LQ  
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} 84^'^nd  
} SA&0f&07i  
//负责部分文件的抓取 F>Rz}-Fy  
**FileSplitterFetch.java x@I*(I  
*/ <l]P <N8^  
package NetFox; py.lGywb_  
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import java.io.*; e*p7(b-  
import java.net.*; zWpJ\/k~  
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public class FileSplitterFetch extends Thread { Gm;)Om_  
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String sURL; //File URL e5KsKzu a  
long nStartPos; //File Snippet Start Position $X8(OS5d'  
long nEndPos; //File Snippet End Position ,#[0As29u  
int nThreadID; //Thread's ID tFt56/4  
boolean bDownOver = false; //Downing is over zY~  
boolean bStop = false; //Stop identical 5vs~8|aRo  
FileAccessI fileAccessI = null; //File Access interface nf&PDv1  

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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Z"PPXv-<jY  
{ 0X@!i3eu  
this.sURL = sURL; b/'{6zn  
this.nStartPos = nStart; 3~Od2nk(x  
this.nEndPos = nEnd; uc!j`G*]  
nThreadID = id; S9R(;  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 fe PH=C  
} X.hU23w  
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public void run() -SZXUN  
{ ,?k[<C  
while(nStartPos < nEndPos && !bStop) 7S$Am84%  
{ eqbQ,, &  
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try{ 2g5i3C.q$  
URL url = new URL(sURL); HA&7 ybl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
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httpConnection.setRequestProperty("User-Agent","NetFox"); Z-|.j^n  
String sProperty = "bytes="+nStartPos+"-"; |S.G#za  
httpConnection.setRequestProperty("RANGE",sProperty); I^"ouM9}Q  
Utility.log(sProperty); /aS=vjs  
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InputStream input = httpConnection.getInputStream(); yO*~)ALb+  
//logResponseHead(httpConnection); cb!mV5M-g  
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byte[] b = new byte[1024]; "1O!Ck_n  
int nRead; %@tKcQ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) O ]o7  
{ MB.\G.bV  
nStartPos += fileAccessI.write(b,0,nRead); &_Kb;UVRj  
//if(nThreadID == 1) j6v|D>I  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :5Vk+s]8  
}  [U9b_`  
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Utility.log("Thread " + nThreadID + " is over!"); MmiC%"7wt  
bDownOver = true; ^mxOQc !  
//nPos = fileAccessI.write (b,0,nRead); ZoX24C
'  
} m>yb}+  
catch(Exception e){e.printStackTrace ();} S3#NGBZ/  
} B1<:nl  
} D.d(D:  
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//打印回应的头信息 $ N`V%<W  
public void logResponseHead(HttpURLConnection con) 9U[Gh97Sf  
{ ldp x,  
for(int i=1;;i++) <xM$^r)  
{ DfYOGs]@  
String header=con.getHeaderFieldKey(i); 3ARvSz@5  
if(header!=null) Gk_%WY*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Z]?Tx2|7  
Utility.log(header+" : "+con.getHeaderField(header)); N(i%Oxp1  
else HYVSi3[  
break; MK
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} tGt/=~n9  
} iMG)zPj  
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public void splitterStop() vJZ0G:1  
{ 8vQGpIa,
 
bStop = true; \H<gKZquR  
} >,c$e' h  
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} O-m=<Fk> D  
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/* &L7u//  
**FileAccess.java C]S~DK1  
*//文件访问(定位，写) B ~u9"SR.  
package NetFox; $t*>A+J  
import java.io.*; |-Rg].  
=$bJ`GpJ  
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public class FileAccessI implements Serializable{ oCtg{*vp  
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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 nW)-bAV<  
RandomAccessFile oSavedFile; =^liong0  
long nPos; lMkDLobos  
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public FileAccessI() throws IOException d)@Hx8  
{ EY3x o-H  
this("",0); 'I$-h<W  
} SCwAAE9s]  
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public FileAccessI(String sName,long nPos) throws IOException u&4CXv=  
{ mCM7FFl I  
oSavedFile = new RandomAccessFile(sName,"rw"); b1+6I_u.  
this.nPos = nPos; H~Z$pk%  
oSavedFile.seek(nPos); qY,z,oAF  
} ~nit~;  
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public synchronized int write(byte[] b,int nStart,int nLen) 7 s+j)  
{ un*Ptc2%  
int n = -1; (pBPf  
try{ jbQ N<`!  
oSavedFile.write(b,nStart,nLen); XKp$v']u  
n = nLen; E`E$ }iLs  
} bBx.snBK  
catch(IOException e) !Cqm=q{K  
{ Wp2W:JX:  
e.printStackTrace (); @|I:A  
} R$>]7-N}  
@ P:b\WCI  
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return n; 2bJqZ,@  
} P:~Xaz\F  
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} :+ASZE.  
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/* 8PN/*Sa  
**SiteInfoBean.java |aAu4
 
*/ :ik$@5wp  
package NetFox; VV_Zrje  
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public class SiteInfoBean { ~Onj|w7  
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private String sSiteURL; //Site's URL /6?A#%hc  
private String sFilePath; //Saved File's Path o0yyP,?yh  
private String sFileName; //Saved File's Name @M]uUL-ze  
private int nSplitter; //Count of Splited Downloading File O~p@87aq  

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public SiteInfoBean() m=saUhI*9  
{//nSplitter的缺省值为5 gKp5*  
//default value of nSplitter is 5 s=[Tm}[  
this("","","",5);  Lg;b17  
} ,^Cl?\9"  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) p3m!Iota  
{ mbf'xG
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sSiteURL= sURL; ;-aF\}D@n  
sFilePath = sPath; /]xu=q2  
sFileName = sName; sl5y1W/]]  
this.nSplitter = nSpiltter; FJ/>=2^B  
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"7]YvZYu0  
} >DFpL$oP  
n;Nr[hI  
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public String getSSiteURL() p"xti+2,  
{ o{W4@:Ib  
return sSiteURL; R*"31&3le4  
} Qkk3>{I  
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3 s@6pI  
public void setSSiteURL(String value) ^)JUl!5j]C  
{ @ij8AGE:  
sSiteURL = value; oVD)Fb%[i9  
} u~uR:E%'C  
z%4E~u10  
{Df97n%h;  
public String getSFilePath() #  
{ 1 #zIAN>  
return sFilePath; NWSm  
} )aV\=a |A  
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}NH\Q$IU  
public void setSFilePath(String value) fXL&?~fS  
{ QU#u5sX A  
sFilePath = value; wgN)*dpuI
 
} P#8+GN+bF  
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public String getSFileName() n+sV$*wvS  
{ wqB 5KxO  
return sFileName; 3Y;<Q>roT  
} 9_$i.@L1  
T%[&[8{8  
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public void setSFileName(String value) &J]|pf3m  
{ 46yq F  
sFileName = value; [Iwb7a0p  
} m L#%H(  
lmsO 6=I4F  
35;UE2d)<  
public int getNSplitter() {?!0<0  
{ /k$H"'`j4  
return nSplitter; Wzn!BgxRr  
} JU6PBY~C'  
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public void setNSplitter(int nCount) 7Gos-_s  
{ !nm[ZrSP  
nSplitter = nCount; 5W Z9z-6  
} nDFF,ge;a#  
} ms(Z1ix^  
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/* h/LlH9S:!  
**Utility.java ^(Y}j8sj  
*/ \68x]q[  
package NetFox; Dc1tND$X3g  
2cB){.E  
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public class Utility { ]* #k|>Fl  
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public Utility() M*+MhM-  
{ tc|`cB3f  
?<*mIf:?  
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} hja;d1yH  
kPuI'EPK  
//线程睡眠 ~Z{IdE  
public static void sleep(int nSecond) ~xp(k  
{ SU`RHAo  
try{ $-=QTX  
Thread.sleep(nSecond); TJ5g?#Wul  
} 7CGxM  
catch(Exception e) G1!yPQa7d  
{ 34Fc oud);  
e.printStackTrace (); Bd8{25{c  
} dF`\ewRFn  
} +A!E 6+'  
c; MF  
//日志 pA%Sybw+  
public static void log(String sMsg) +Cf  
{ en5sqKqh+  
System.err.println(sMsg); q!qOy/}D  
} Ir,3' G  
-|FSdzvg  
@[2Go}VF  
public static void log(int sMsg) b3vPGR  
{ fOHgz,x=  
System.err.println(sMsg); 2omKP,9,2  
} AB:JXMyK  
} O^2@9 w  
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/* T, z80m}  
**TestMethod.java 5gg Yg$  
*/ b@>MA  
package NetFox; c1wP/?|.>  
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public class TestMethod { 8M~^/
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}~akVh`3  
-".q=$f  
public TestMethod() |Y9mre.Y;  
{ ///xx/weblogic60b2_win.exe Qm >x?  
try{ =.Hq]l6+  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %77X/%.Y  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); z2 m(<zb  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 6F)^8s02h  
fileFetch.start(); $GI
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} Pw:{  
catch(Exception e){e.printStackTrace ();} f)b+>!  
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} sx]kH$  
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public static void main(String[] args) Rt6(y #dF  
{ \I[f@D-J  
new TestMethod(); nRSiW*;R  
} kLfk2A;'i  
} Y+kfMAv  
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