http断点续传简单实现（java)

/* .?7So3  
**SiteFileFetch.java {&b-}f"m  
*/ ^)'||Ly  
package NetFox; ,|>nF;.Y  
import java.io.*; otZ JY)  
import java.net.*; vKV{ $|  
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public class SiteFileFetch extends Thread { 0MhxFoFO  
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SiteInfoBean siteInfoBean = null; //文件信息Bean -hm9sNox  
long[] nStartPos; //开始位置 t"
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long[] nEndPos; //结束位置 }8X:?S %  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +0)5H>h  
long nFileLength; //文件长度 {S# 5g2  
boolean bFirst = true; //是否第一次取文件 OQ 0b$qw  
boolean bStop = false; //停止标志 $M%}Oz3*  
File tmpFile; //文件下载的临时信息 2}1!WIin  
DataOutputStream output; //输出到文件的输出流 |oB]6VS`  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） gB'`I(q5.  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1W4H-/Re  
{ %0go%_  
siteInfoBean = bean; P}b Dn;  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \>_eEZ5  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); <kk'v'GW@  
if(tmpFile.exists ()) 72% {Wh/  
{ ~9]Vy (L  
bFirst = false; 1gO//fdI  
read_nPos(); IrUpExJ  
} 9 ?[4i'  
else rUhWZta  
{ )Ep@$Gv|S  
nStartPos = new long[bean.getNSplitter()]; -1dIZy  
nEndPos = new long[bean.getNSplitter()]; yzODF>KJ  
} :  ,|=Q}  
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} bK6, saN>  
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public void run()  :^C#-O  
{ DB!uv[c  
//获得文件长度 t4*aVHT  
//分割文件 /<Gyg7o0  
//实例FileSplitterFetch 4j2~"K  
//启动FileSplitterFetch线程 UEk|8yq  
//等待子线程返回 7UY('Q[  
try{ pyGFDB5_P  
if(bFirst) &FT5w T  
{ *s 1D\/H  
nFileLength = getFileSize(); ,<IL*=a  
if(nFileLength == -1) pvK \fSr  
{ 1j_aH#Fz:  
System.err.println("File Length is not known!"); 5QCw5N  
} F^J&g%ql  
else if(nFileLength == -2) 0fEZD$  
{ xow6@M,  
System.err.println("File is not access!"); dpl"}+  
} Vu^Q4Z  
else 2*b#+b  
{ !^rITiy  
for(int i=0;i<nStartPos.length;i++) gt(X!iN]  
{ Ss*LgK
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); R A-^!4tX  
} ~M|NzK_9  
for(int i=0;i<nEndPos.length-1;i++) `K@5_db\  
{
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nEndPos = nStartPos[i+1]; ~{kA) :  
} Uj y6vgU;  
nEndPos[nEndPos.length-1] = nFileLength; F=P+;%.  
} Mr@<ZTw  
} hJs&rpN  
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//启动子线程 D"1vw<Ak  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; j X^&4f  
for(int i=0;i<nStartPos.length;i++) !c3Qcva  
{ vgd}09y  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), loAfFK>g  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), (dw3'W  
nStartPos,nEndPos,i); OoA5!HEh  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?}!g
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fileSplitterFetch.start(); W_Ws3L1;N  
} htNL2N  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @p?b"?QaB  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3(XHF3q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", [v>Z(  
nEndPos = " + nFileLength); Al;%u0]5  
// fileSplitterFetch[nPos.length-1].start(); Q)7L
^  
{g23[$X]N  
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//等待子线程结束 xP|%rl4  
//int count = 0; ]-+.lR%vd9  
//是否结束while循环 kfG65aa>_  
boolean breakWhile = false; N23+1h  
;8 /+wBnm  
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while(!bStop) a`GN@ 8  
{ E:LQ!  
write_nPos(); 9|?(GG  
Utility.sleep(500); ;Fwm1ezx0  
breakWhile = true; nATfmUN L  
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for(int i=0;i<nStartPos.length;i++) xhp-4  
{ 6O[wVaC1u  
if(!fileSplitterFetch.bDownOver) A(_^_p.|  
{ av|6r#  
breakWhile = false; 1'@lg*^9  
break; eO[Cb]Dy:  
} bo?3E +B  
} ]CtoK%k  
if(breakWhile) e-duZ o  
break; DftGy:Ah3  
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//count++; %o
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//if(count>4) g)|++?  
// siteStop(); 3 MI) E  
} EY[
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System.err.println("文件下载结束！"); olQ8s*  
} AD4L`0D  
catch(Exception e){e.printStackTrace ();}  6@Z'fT4  
} s5Bmv\e.i5  
4jyr\=42F'  
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//获得文件长度 qyG636i  
public long getFileSize() e8ig[:B>+  
{ u^4"96aXJ  
int nFileLength = -1; 1RUbY>K#U  
try{ >stVsFdV)  
URL url = new URL(siteInfoBean.getSSiteURL()); p'w"V6k('~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U!-+v:SF  
httpConnection.setRequestProperty("User-Agent","NetFox"); "3>*i!i  
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int responseCode=httpConnection.getResponseCode(); %?9r
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if(responseCode>=400) R4rm>zisVX  
{ O|7{%5h  
processErrorCode(responseCode); Ns(L1'9=  
return -2; //-2 represent access is error Vlxb<$5Nh  
} yPxG`w'  
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String sHeader; q MT.7n:  
-GkK[KCH  
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for(int i=1;;i++) S&)) 0d  
{ +qW w
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); qzbkxQu]g  
//Utility.log(in.readLine()); ?GD?J(S  
sHeader=httpConnection.getHeaderFieldKey(i); ]OCJ~Zw  
if(sHeader!=null) -L4G WJ~.-  
{ %F]9^C+  
if(sHeader.equals("Content-Length")) n4_:#L?  
{ 'rq#q)1MT  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); E{]|jPdr  
break; 'Tan6Qa  
} mEc;-b f  
} g KmRjK  
else `J7L
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break; f[I'
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} pNf9  
} ]ieA?:0Hi  
catch(IOException e){e.printStackTrace ();} f/WM}Hpj  
catch(Exception e){e.printStackTrace ();} i7!mMO8]  
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Utility.log(nFileLength); Z6/~2S@  
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return nFileLength; Y1ilH-8  
} S%gO6&
^  
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j6d"8oH _  
//保存下载信息（文件指针位置） byj mH  
private void write_nPos() G mUs U{  
{ 41Q   
try{ huD\dmQ:]  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Rc.<0#  
output.writeInt(nStartPos.length); {hq ;7  
for(int i=0;i<nStartPos.length;i++) <GmrKdM  
{ hz|z&vyP  
// output.writeLong(nPos); {S:3 FI  
output.writeLong(fileSplitterFetch.nStartPos); uV$d7(N}"  
output.writeLong(fileSplitterFetch.nEndPos); &*:)5F5  
} 7LZb*+>  
output.close(); ].T;x|  
} 5!Mp#lO  
catch(IOException e){e.printStackTrace ();} C`T5d  
catch(Exception e){e.printStackTrace ();} h/bYtE  
} ?UhAjtYIS  
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>,]e[/p  
//读取保存的下载信息（文件指针位置） y!c7y]9__2  
private void read_nPos() ez:o9)N4  
{
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try{ ]}L1W`n  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #V,~d&_k  
int nCount = input.readInt(); xjk|O;ak  
nStartPos = new long[nCount]; S^`9[$KH0  
nEndPos = new long[nCount]; Ty|c@X  
for(int i=0;i<nStartPos.length;i++) F*( A; N_y  
{ pC.4AkEO  
nStartPos = input.readLong(); N4(VRA  
nEndPos = input.readLong(); :yFCp@&  
} >s?;2T2"yx  
input.close(); 1Kf t?g  
} lGBdQc]IL  
catch(IOException e){e.printStackTrace ();} ITqigGan%  
catch(Exception e){e.printStackTrace ();} LmdV@gR  
} mb`}sTU).  
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private void processErrorCode(int nErrorCode) R
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{ 0Lz56e'j  
System.err.println("Error Code : " + nErrorCode); Q/`o6xv  
} 1xV1#'@[Jd  
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m]}"FMH$  
//停止文件下载 19{?w6G<k  
public void siteStop() b/}0 &VXo  
{ &r%^wfp  
bStop = true; r9'H7J  
for(int i=0;i<nStartPos.length;i++) 92_H!m/  
fileSplitterFetch.splitterStop(); 'R5l =Wf  
nln[V$   
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} I[IQFka}  
} OL"5A18;M  
//负责部分文件的抓取 <l/Qf[V  
**FileSplitterFetch.java s/0FSv x  
*/ >:nJTr  
package NetFox; R:m=HS_  
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import java.io.*; >mSl~.I2  
import java.net.*; #@"rp]1xv  
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public class FileSplitterFetch extends Thread { +NMSvu_?  
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4\WkXwoqQO  
String sURL; //File URL k6XmBBIj-  
long nStartPos; //File Snippet Start Position !@1!ld  
long nEndPos; //File Snippet End Position Mo|5)8_  
int nThreadID; //Thread's ID *n?:)(  
boolean bDownOver = false; //Downing is over 6T_c#G5  
boolean bStop = false; //Stop identical nW*Oo|p~=  
FileAccessI fileAccessI = null; //File Access interface zb)SlR  
]J]p:Y>NL  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &c ~)z\$  
{ X^^D[U  
this.sURL = sURL; TL:RB)- <  
this.nStartPos = nStart; h;[Ncj]  
this.nEndPos = nEnd; T=Q{K|JE  
nThreadID = id; $oj<yH<i  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 O~]G(TMs8W  
} &}=,8Gt1G  
{moNtzE;  
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public void run() d>psqmQ  
{ l(4.
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while(nStartPos < nEndPos && !bStop) ,Gx=e!-N5  
{ "g[UX{L  
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try{ "evV/Fg(  
URL url = new URL(sURL); &"n9,$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); SVz.d/3Y  
httpConnection.setRequestProperty("User-Agent","NetFox"); }CqIKoX.  
String sProperty = "bytes="+nStartPos+"-"; zKT<QM!`  
httpConnection.setRequestProperty("RANGE",sProperty); 8}@a?QS(&  
Utility.log(sProperty); <9ph c  
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InputStream input = httpConnection.getInputStream(); PyE<`E  
//logResponseHead(httpConnection); t4uxon
 
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byte[] b = new byte[1024]; ~h+3WuOv  
int nRead; DO{4n1-U  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) (E[hl  
{ &p/k VM  
nStartPos += fileAccessI.write(b,0,nRead); >@
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//if(nThreadID == 1) biK.HL\V  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &|*|  
} >X)G`N@!  
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Utility.log("Thread " + nThreadID + " is over!"); z8MYgn7  
bDownOver = true; _?<Fc8F  
//nPos = fileAccessI.write (b,0,nRead); e0 EJ[bG  
} F4Z0g*^x  
catch(Exception e){e.printStackTrace ();} ,/9|j*9H  
} Jq)k?WS  
} x|5/#H  
5Px_vtqP  
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//打印回应的头信息 ]uf_"D  
public void logResponseHead(HttpURLConnection con) P*]g*&*Y +  
{ u1<kdTxA N  
for(int i=1;;i++) [%:NR  
{ Pp!W$C:  
String header=con.getHeaderFieldKey(i); `BY`ltW  
if(header!=null) (FHh,y~v  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )cXc"aj@s  
Utility.log(header+" : "+con.getHeaderField(header)); z>~3*a9&  
else $i Tgv?.Q  
break; s<]l[Y>  
} "'(4l 2.  
}

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public void splitterStop() ,;y^|X  
{ o 8U2vMH  
bStop = true; 'Ud5;?
{  
} zFIKB9NUn  
{]]I4a  
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} HY:
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o
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/* 2rM i~8T  
**FileAccess.java P
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*//文件访问(定位，写) MiRB*eA  
package NetFox; ~5b %~:  
import java.io.*; 107SXYdhI  
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public class FileAccessI implements Serializable{ O
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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 oCS NA.z  
RandomAccessFile oSavedFile; Mtr~d  
long nPos; bMYRQ,K`C  
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public FileAccessI() throws IOException x4K
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{ FKP^f\!M  
this("",0); 
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} NINiX(  
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public FileAccessI(String sName,long nPos) throws IOException Gex^\gf  
{ 2StpcAlU}  
oSavedFile = new RandomAccessFile(sName,"rw"); n_Z8%|h  
this.nPos = nPos;
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oSavedFile.seek(nPos); EMo6$(  
} "M tQj}  
yY+2;`CH  
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public synchronized int write(byte[] b,int nStart,int nLen) "?!IPX2\S  
{ b8Qm4b?:4  
int n = -1; ~oI49Q&{  
try{ t9}XO M*  
oSavedFile.write(b,nStart,nLen); F-6* BUqJ  
n = nLen; @N$r'@  
} $W2AiE[Wm  
catch(IOException e) +J} 41  
{ fiZ8s
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e.printStackTrace (); >cp9{+#f  
} -'2.^a-8-g  
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return n; *=8)]_=f  
} +2?[=g4;}  
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} ! 9e>J  
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/* ^$(|(N[;   
**SiteInfoBean.java BC+HP9<]  
*/ qhtc?A/0}  
package NetFox; )q,}jeM8  
:/3`+&T^/  
nF-FoO98  
public class SiteInfoBean { Z6=!}a%  
/H)g<YA  
iw{n|&Y#`  
private String sSiteURL; //Site's URL cA*%K[9  
private String sFilePath; //Saved File's Path {MS&t09Wh  
private String sFileName; //Saved File's Name P+/L,u  
private int nSplitter; //Count of Splited Downloading File gSC@uf  
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kU /?#s  
public SiteInfoBean() 1ysA~2  
{//nSplitter的缺省值为5 buoz La  
//default value of nSplitter is 5 .q=X58tHu  
this("","","",5); mH?hzxa+  
} xU&rUk/L  
@ZVc!5J_,  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) H\^^p!^)  
{ 1Nz\3]-  
sSiteURL= sURL; ..!yf e"5  
sFilePath = sPath; LV[4zo]=  
sFileName = sName; kxP6#8*:  
this.nSplitter = nSpiltter; y
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%guot~S|  
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} z7CYYU?  
#wo_  
4eKJ\Q=nX5  
public String getSSiteURL() M]W4S4&Y=  
{ YcI]_[  
return sSiteURL; 5Ql6?UHD  
} <[q)2 5RL  
A-~)7-  
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public void setSSiteURL(String value) k4@GjO1"$  
{ #\jPBLc  
sSiteURL = value; H0Tt(:.&  
} T&c[m!}X|t  
7+c@pEU]  
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public String getSFilePath() 1{wy%|H\  
{ 41.+3VP  
return sFilePath; RsbrD8*AD  
} vw3W:TL  
2vwT8/  
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public void setSFilePath(String value) ZGrV? @o,6  
{ [`&cA#C9Yp  
sFilePath = value; >A)he!I  
} ua{eri[  
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}X$>84s>[P  
public String getSFileName() 5ZSw0A(w  
{ 5t PmrWZ  
return sFileName; $&4Zw6"=  
} ;R67a V,  
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public void setSFileName(String value) XH. _Z  
{ HqbTJ!a  
sFileName = value; ED6H  
} Q.N^1?(>k  
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a
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public int getNSplitter() <sTaXaq?  
{ T4UY%E!0  
return nSplitter; 2|T@  
} mMMu'N  
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public void setNSplitter(int nCount) 4, :D4WYWD  
{ 7fVVU+y  
nSplitter = nCount; Uq&|iB#mF  
} n;MoMGnPh,  
} a5)+5  
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l0 1Lg6+S  
/* []Z6<rC|  
**Utility.java 4jXyA/F9V  
*/ FPqgncBHK  
package NetFox; $UH_)Q2#J^  
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public class Utility { 0 cQf_o  
:9)>!+|'  
l+#`  
public Utility() $Fo ,$  
{ iX,Qh2(ig  
vEb~QX0~  
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} P}PSS#nn  
(cMrEuv  
//线程睡眠 U9@q"v-  
public static void sleep(int nSecond) wU=(_S,c  
{ Ji7A9Hk  
try{ ;[|x5o/<  
Thread.sleep(nSecond); gcz1*3)  
} j;'NJ~NZ$  
catch(Exception e) ~r{Nc j  
{ gh~C.>W}q+  
e.printStackTrace (); lr|-_snx2  
} 0 xXAhv-)O  
} j\ )Qn2r  
-?GYW81Q  
//日志 Lrk^<:8;  
public static void log(String sMsg) Xc@4(Nyp  
{ jHFdDw|N`  
System.err.println(sMsg); "zqt'b0bW  
} R; IB o  
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VA]%i P,O-  
public static void log(int sMsg) xX&*&RPZ  
{ ch-GmAj 9  
System.err.println(sMsg); #)\KV7f!;  
} !?KY;3L:  
} x|Q6[Y  
Y!SD^Ie7!  
Pukq{/27  
/* c,+oH<bZZs  
**TestMethod.java `T mIrc  
*/ %Jw;c`JM  
package NetFox; ;DRJL   
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?1[go+56X  
public class TestMethod { c  xX  
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|S.-
5CAh4  
public TestMethod() Y H?>2u  
{ ///xx/weblogic60b2_win.exe pE=wP/#  
try{  Im#3sn  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2Ay2 G-  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?.4u'Dkn=  
SiteFileFetch fileFetch = new SiteFileFetch(bean); N!P* B$d  
fileFetch.start(); al^ yCoB  
} WjA)0HL(  
catch(Exception e){e.printStackTrace ();} b]J_R"}  
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} ]ao]?=q C  
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x*_c'\F|  
public static void main(String[] args) )EO$JwQ  
{ 4YdmG.CU  
new TestMethod(); /423!g0Q  
} :CV&WP  
} aZmSCi:&'  
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