http断点续传简单实现（java)

/* XW)lDiJl  
**SiteFileFetch.java a fW@T2  
*/ YHygo#4=8  
package NetFox; Pw`8Wj  
import java.io.*; yZU6xY  
import java.net.*; 6HWE~`ok6  
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public class SiteFileFetch extends Thread { r1{@Ucw2  
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SiteInfoBean siteInfoBean = null; //文件信息Bean czgO ;3-C  
long[] nStartPos; //开始位置 " 9wvPC ^  
long[] nEndPos; //结束位置 yEoF4bt  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Ww+IWW@  
long nFileLength; //文件长度 2*l/3VW  
boolean bFirst = true; //是否第一次取文件 ZI}Fom<  
boolean bStop = false; //停止标志 ,K"U>&  
File tmpFile; //文件下载的临时信息 ]dmrkZz:  
DataOutputStream output; //输出到文件的输出流 &d?CCb$|0Y  
}?_?V&K|  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） qvKG-|j  
public SiteFileFetch(SiteInfoBean bean) throws IOException z3m85F%dR  
{ u?<%q!  
siteInfoBean = bean; yfjWbW  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Z4w!p?Wqa  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 6@F9G4<Z  
if(tmpFile.exists ()) sW'AjI  
{ dhf!o0'1M  
bFirst = false; u5b|#&-mX  
read_nPos(); Y>dzR)~3[  
} W ]?G}Q;  
else X Dm[Gc>(~  
{ pG^  
nStartPos = new long[bean.getNSplitter()]; m6\E$;`  
nEndPos = new long[bean.getNSplitter()]; ~#[yJNYQ  
} .K2qXw"S#  
n&qg;TT  
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} CMG&7(MR  
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aU "8{  
public void run() li'YDtMKCY  
{ JWhdMU  
//获得文件长度 :tB1D@Cb6  
//分割文件 iDz++VN
V  
//实例FileSplitterFetch Sc1 8dC0  
//启动FileSplitterFetch线程 gpvYb7Of0  
//等待子线程返回 kY|utoAP  
try{ H.|#c^I  
if(bFirst) (
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{ FF(#]vz'  
nFileLength = getFileSize(); `O!X((  
if(nFileLength == -1)
/
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{ lH x^D;m6  
System.err.println("File Length is not known!");
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} SpLzm A  
else if(nFileLength == -2) rv^@,8vq  
{ n&;85IF1  
System.err.println("File is not access!"); TA`1U;c{n  
} =_ ./~  
else (y
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{ WwBOM~/`2  
for(int i=0;i<nStartPos.length;i++) ;
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{ L:pYn_  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ]7F=u!/`<C  
} 2W96Zju\  
for(int i=0;i<nEndPos.length-1;i++) HV!m8k=6  
{ JPc+rfF  
nEndPos = nStartPos[i+1]; $%CF8\0  
} sV{,S>s  
nEndPos[nEndPos.length-1] = nFileLength; Sw8]EH6  
} +mmSfuO&\  
} 3G)#5Lf<  
7uS~MW  
?GoR^p #p  
//启动子线程 l|~A#kq  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; rb2S7k0{  
for(int i=0;i<nStartPos.length;i++) Jr ,;>   
{ D3Ig>gKo?m  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "$Z= %.3Q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), J6s`'gFns  
nStartPos,nEndPos,i); qo90t{|c  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ustv{:7v  
fileSplitterFetch.start(); <ro7vPKNa  
} uk<4+x,2)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8 S:w7Hr  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &Fzb6/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", B:;pvW]  
nEndPos = " + nFileLength); 8>2.UrC  
// fileSplitterFetch[nPos.length-1].start(); j9x<Y]  
nzuX&bSw  
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//等待子线程结束 7a=gH2]&  
//int count = 0; L%*!`T
N  
//是否结束while循环 hYT0l$Ng  
boolean breakWhile = false; *
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while(!bStop) J{p1|+h%  
{ 6y%qVx#!  
write_nPos(); g2LM_1\  
Utility.sleep(500); pXT4)JDpc  
breakWhile = true; ^pAAzr"h
v  
N ,'GN[s  
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for(int i=0;i<nStartPos.length;i++) -LoZs ru  
{ 8`q:Gz=M\  
if(!fileSplitterFetch.bDownOver) ]_mb7X>  
{ =r?hgGWe  
breakWhile = false; |C;=-|  
break; AW%#O\N  
} ?>D+ge  
} (Du@ S  
if(breakWhile) Zw 26  
break; IXMop7~  
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LvH4{B  
//count++; =\&;Fi]  
//if(count>4) =V,mtT  
// siteStop(); DbBcQ%  
} a?I= !js  
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iTBx\u%{  
System.err.println("文件下载结束！"); &=@IzmA  
} \+oQd=K@  
catch(Exception e){e.printStackTrace ();} $B2J T9  
} o8V5w!+#  
?(' wn<  
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//获得文件长度 fa jGZyd0:  
public long getFileSize() :KSV4>X[%a  
{ rKe2/4>0X  
int nFileLength = -1; fy>{QC\  
try{
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URL url = new URL(siteInfoBean.getSSiteURL()); v+W&9>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )al]*[lY  
httpConnection.setRequestProperty("User-Agent","NetFox"); %~O,zs.2p  
e
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int responseCode=httpConnection.getResponseCode(); 2@n{yYwy  
if(responseCode>=400) X[-xowE-  
{ `&r+F/Ap2  
processErrorCode(responseCode); #`qx<y*S  
return -2; //-2 represent access is error dc+>m,3$  
} !fV+z%:  
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String sHeader; |PvPAPy)uu  
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for(int i=1;;i++) 9%o32eo,3  
{ +xh`Q=A  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); L4@K~8j7  
//Utility.log(in.readLine()); B?eCe}*f;B  
sHeader=httpConnection.getHeaderFieldKey(i); 0JWDtmK=C  
if(sHeader!=null) !j
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{ wjU9ZGM  
if(sHeader.equals("Content-Length")) GL>O4S<`  
{ afCW(zHp  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); yJ[0WY8<kC  
break; Hck]aKI+  
} G*?8MTP8![  
} a(m2n.0'>  
else e[{0)y>=  
break; uP`Z12&  
} `[y^ :mj  
} NJ%P/\ C  
catch(IOException e){e.printStackTrace ();} +C^nO=[E  
catch(Exception e){e.printStackTrace ();} _>o:R$ %}  
w1FcB$  
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Utility.log(nFileLength); =}<IfNA  
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return nFileLength; k90YV(  
} iOf<$f  
$H2u.U<ip  
*l(7D(#  
//保存下载信息（文件指针位置） 3p$?,0ELH  
private void write_nPos() *[Imn\hu  
{ `Y0%cXi3  
try{ R)?*N@.s  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ,5P0S0*{  
output.writeInt(nStartPos.length); [CTnXb  
for(int i=0;i<nStartPos.length;i++) /m!BY}4W  
{ #JqB ;'\  
// output.writeLong(nPos); xS5vbJ  
output.writeLong(fileSplitterFetch.nStartPos); ^7`BP%6  
output.writeLong(fileSplitterFetch.nEndPos); }g@v`5  
} dUD[e,?  
output.close(); WSPI|#Xr%  
} 8$]1M,$r  
catch(IOException e){e.printStackTrace ();} :^<3>zk  
catch(Exception e){e.printStackTrace ();} Q8$}@iA[  
} Ex.yU{|c  

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//读取保存的下载信息（文件指针位置） ,Y@Gyx!4  
private void read_nPos() 4XL^D~V  
{ oe ~'o'  
try{ :ffY6L+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); HRpte=`q  
int nCount = input.readInt(); $o!zUH~'v  
nStartPos = new long[nCount]; tb 5`cube  
nEndPos = new long[nCount]; kx8G  
for(int i=0;i<nStartPos.length;i++) `](e:be}  
{ NYhB'C2  
nStartPos = input.readLong(); RV1coC.g4x  
nEndPos = input.readLong(); i}(LqcYU  
} Do9x XK  
input.close(); M.JA.I@XC  
} `T1  
catch(IOException e){e.printStackTrace ();} g%aYD
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catch(Exception e){e.printStackTrace ();} W PC]%:L"  
} .zf~.R;>  
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private void processErrorCode(int nErrorCode) "6A `
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{ {aZ0;  
System.err.println("Error Code : " + nErrorCode); RCJ|P~*  
} IM*y|UHt  
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T%+#xl  
//停止文件下载 \-E^lIVF  
public void siteStop() ??5Q)Erm1  
{ pG_;$8Hc  
bStop = true; k``_EiV4t  
for(int i=0;i<nStartPos.length;i++) pt?bWyKG  
fileSplitterFetch.splitterStop(); R- X5K-  
]43/`FX  
L]7=?vN=8  
} />C^WQI^  
} 53_Hl]#qZ  
//负责部分文件的抓取 "%)qRe  
**FileSplitterFetch.java \Zk;ikEY  
*/ cUk7i`M;6  
package NetFox; `Uq#W+r,  
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import java.io.*; ~Za
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import java.net.*; eNh39er  
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public class FileSplitterFetch extends Thread { G+9,,`2  
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H;mSkRD3N  
String sURL; //File URL %64)(z  
long nStartPos; //File Snippet Start Position `K"L /I9  
long nEndPos; //File Snippet End Position v4<nI;Ux  
int nThreadID; //Thread's ID \Dm";Ay>  
boolean bDownOver = false; //Downing is over 3l]lwV  
boolean bStop = false; //Stop identical 'B$
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FileAccessI fileAccessI = null; //File Access interface &/Z /Y ]  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 7jrt7[{
 
{ +D6YR$_<  
this.sURL = sURL; ';k5?^T  
this.nStartPos = nStart; W<{h,j8  
this.nEndPos = nEnd; |o"?gB}Dh  
nThreadID = id; sQ3[<  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 h#I>M`|  
} $V
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public void run() Mc lkEfn  
{ ]2A^1Del  
while(nStartPos < nEndPos && !bStop) S)(.,x  
{ + /G2fhE  
- nm"of\o  
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try{ 4(n-_BS  
URL url = new URL(sURL); eSn+B;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1y&\5kB  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1NFsb-<u  
String sProperty = "bytes="+nStartPos+"-"; J6"9v;V  
httpConnection.setRequestProperty("RANGE",sProperty); -]Bq|qTH[(  
Utility.log(sProperty); >tS'Q`R
 
*][`@@->  
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InputStream input = httpConnection.getInputStream(); 63iUi9P  
//logResponseHead(httpConnection); n)/z0n!\  
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\
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byte[] b = new byte[1024]; -/B+T>[nTb  
int nRead; Z3e| UAif  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) /V8#[9K  
{ y
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nStartPos += fileAccessI.write(b,0,nRead); ,oe <  
//if(nThreadID == 1) u]wZQl#-  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .8g)av+  
} nUr5Qn?  
8$cLG*=h4  
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Utility.log("Thread " + nThreadID + " is over!"); )CYGQMK  
bDownOver = true; w_c"@CjkE  
//nPos = fileAccessI.write (b,0,nRead); <V'@ks%  
} L- iy  
catch(Exception e){e.printStackTrace ();} qx(xvU9  
} %QH$ipM  
} _{O>v\u  
3Aip}<1  
*"2+B&Y  
//打印回应的头信息 s
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public void logResponseHead(HttpURLConnection con) S>+|OCl";  
{ hNiE\x  
for(int i=1;;i++) ^#-l q)  
{ @s>Czm5  
String header=con.getHeaderFieldKey(i); N];NAMp  
if(header!=null) dbLZc$vPj  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >=lC4Tu  
Utility.log(header+" : "+con.getHeaderField(header)); G>_*djUf  
else 2szPAuN+  
break; lBE=(A`  
} H'5)UX@LP  
} eIF5ZPSZi  
?,Xw[pR  
je-!4r,  
public void splitterStop() 5pG}Yk_(x  
{ tFn)aa~L  
bStop = true; +480 l}  
} JG.y,<xW  
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} P:S.~Jq  
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/* Q}JOU  
**FileAccess.java 2W(s(-hD  
*//文件访问(定位，写) m 0C@G5  
package NetFox; X05/uX{  
import java.io.*; h&iC;yj=  
K3&qq[8.e  
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public class FileAccessI implements Serializable{ ztY}5A2`  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 s)t@ol  
RandomAccessFile oSavedFile; M?49TOQA  
long nPos; ;d$rdFA_  
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public FileAccessI() throws IOException bs&4
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{ }K>d+6qk5  
this("",0); \K{ z  
} iMh#TUlQEQ  
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public FileAccessI(String sName,long nPos) throws IOException 8`{:MkXP  
{ (m}'4et~L  
oSavedFile = new RandomAccessFile(sName,"rw"); a!SiX  
this.nPos = nPos; pF
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oSavedFile.seek(nPos); }&D WaO]J7  
} {WS;dX4  
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public synchronized int write(byte[] b,int nStart,int nLen) <dNOd0e  
{ 3
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int n = -1; T<>,lQs(a  
try{ Q\vpqE!9  
oSavedFile.write(b,nStart,nLen); zI uJ-8T"  
n = nLen; =%O6:YM   
} fbvL7* (  
catch(IOException e) ~=LE0.3[  
{ hE/cd1iJ$  
e.printStackTrace (); )q4[zv9  
} B-Hrex]  
H41?/U,{  
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return n; Qel9G($=  
} {Mk6T1Bkq  
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} |-ALklXr  
#X$\&,Yn"  
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/* ,qwuLBW  
**SiteInfoBean.java Dy&i&5E.-l  
*/ =svN#q5s  
package NetFox; q<<v,ihh  
wJqMa9|  
{Xy5pfW Q  
public class SiteInfoBean { JR|ck=tq  
>y>5#[M!  
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private String sSiteURL; //Site's URL RB\uK 1+  
private String sFilePath; //Saved File's Path >:!5*E5?  
private String sFileName; //Saved File's Name _f,C[C[e&  
private int nSplitter; //Count of Splited Downloading File ({_{\9O,3  
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public SiteInfoBean() :-Z2:
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{//nSplitter的缺省值为5 qR{=pR  
//default value of nSplitter is 5 hfTY.  
this("","","",5); ?^{Ah}x  
} Izc\V9+  
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kD%( _K5  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }8z?t:|S  
{ ]W!0$'
o  
sSiteURL= sURL; !qg`/y9  
sFilePath = sPath; vr l-$ii  
sFileName = sName; u=sp`%?  
this.nSplitter = nSpiltter; l)\! .X  
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+sA2WK]  
} |df Pki{  
5qm`J,~k  
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public String getSSiteURL() b%`1cV  
{ ;'K5J9k  
return sSiteURL; w&#]
-|$  
} &z3o7rif$  
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public void setSSiteURL(String value) aXYY:;  
{ Y.UFbrv  
sSiteURL = value; 'H!Uh]!  
} ,4$>,@WW~  
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public String getSFilePath() n\DV3rXI9  
{ Lq^)R  
return sFilePath; {
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} f}e`X
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<'*LRd$1  
public void setSFilePath(String value) 0~S^
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{ ;^*W+,4WB  
sFilePath = value; *)Zdz9E'1(  
} f6Ah6tb  
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q} >%8;nm  
public String getSFileName() O>,e~#!  
{ t~XN}gMxw  
return sFileName; yf+)6D -9n  
} oPM96 (  
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bd
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public void setSFileName(String value) 7NGxa6wi  
{ i.m^/0!  
sFileName = value; 5;EvNu  
} ,O(hMI85]  
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public int getNSplitter() lo+A%\1  
{ Xv^
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return nSplitter; i/4>2y9/F4  
} tD)J*]G  
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ux4POO3C|  
public void setNSplitter(int nCount) i_%_x*  
{ !|(NgzDP/  
nSplitter = nCount; K|, .C[  
} 1+s;FJ2}  
} 4hj|cCrO  
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/* ZECfR>`x  
**Utility.java e^voW"?%  
*/ <5051UEu  
package NetFox; 2+XAX:YD  
})%{AfDRF  
MQ2}
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public class Utility { upmx $H>  

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public Utility() !a\^Sk /  
{ 75lA%| *X  
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} ]-#DB^EQ  
uY To9A  
//线程睡眠 W>r+h-kR  
public static void sleep(int nSecond) J&_n9$  
{ RA 6w}:sq7  
try{ 9(Xn>G'iT  
Thread.sleep(nSecond); Di{de`  
} wCBplaojJ  
catch(Exception e) :ws<-Qy  
{ (
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e.printStackTrace (); }S
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} ~} ~4  
} Vurqt_nb  
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//日志 dZuOrTplA  
public static void log(String sMsg) UEL_uij  
{ #'`{Qv0,  
System.err.println(sMsg); KI.hy2?e  
} vY3h3o  
n@3>6_^rwT  
[-w%/D%@  
public static void log(int sMsg) y~V(aih}D  
{ *-X[u
:  
System.err.println(sMsg); %BODkc Zh  
} PA*5Bk="q  
} !4!~Lk=  
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/* EU#^7  
**TestMethod.java |7~<Is~*  
*/ lB4WKn=?Kl  
package NetFox; 6S#Cl>v  
 Z\sDUJ  
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public class TestMethod { M6TD"-  
/-s6<e!  
|s_GlJV.  
public TestMethod() DmcZta8n]  
{ ///xx/weblogic60b2_win.exe 1Y,Z %d  
try{ kx^/*~ex  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); K=&>t6s<  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); *qq+jsA6wH  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Zd+bx*rD  
fileFetch.start(); t{>q|0  
} -?a 26o%e  
catch(Exception e){e.printStackTrace ();} ]M3yLYK/P  
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} :!QAC@  
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public static void main(String[] args) `vV7c`K?  
{ !r-F>!~  
new TestMethod(); Q2>gU#  
} :Dp0?&_  
} F'Z,]b'st3  
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