http断点续传简单实现（java)

/* f7Ul(D:j\  
**SiteFileFetch.java UR:aD_h  
*/ O1')nYF7  
package NetFox; tx?dIy;  
import java.io.*; </uOe.l>Q  
import java.net.*; >-&R47G  
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public class SiteFileFetch extends Thread { >#ZUfm{k$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean P`r55@af4  
long[] nStartPos; //开始位置 d[rv1s>i  
long[] nEndPos; //结束位置 a>\vUv*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Ym;*Y !~[  
long nFileLength; //文件长度 cqxVAzb  
boolean bFirst = true; //是否第一次取文件 8Sz})UZ  
boolean bStop = false; //停止标志 Z{?G.L*/  
File tmpFile; //文件下载的临时信息 s3Cc;#  
DataOutputStream output; //输出到文件的输出流 JTi!Xu5Jq  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 8p[)MiC5W^  
public SiteFileFetch(SiteInfoBean bean) throws IOException Vh>Z,()>>@  
{ p~LrPWHSTP  
siteInfoBean = bean; n~VD uKn9  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); <nEi<iAY>U  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); G "P4-  
if(tmpFile.exists ()) f6$b s+oP  
{ q -8t'7  
bFirst = false; 3Hf0MAt  
read_nPos(); .s$
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} D7_*k%;@  
else VK@!lJu!  
{  Q1@A2+ c  
nStartPos = new long[bean.getNSplitter()]; 9m
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nEndPos = new long[bean.getNSplitter()]; |7x\m t  
} yA47"R  
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} /dnCwFXf  
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public void run() )>BHL3@  
{ $.]l!cmi%Q  
//获得文件长度 86nN"!{l:  
//分割文件 arf8xqR-U]  
//实例FileSplitterFetch +^;JS3p@\  
//启动FileSplitterFetch线程 <$JaWL  
//等待子线程返回 s(W|f|R  
try{ +{
/  
if(bFirst) g}]t[}s1]  
{ # W"=ry3{  
nFileLength = getFileSize(); ?6'rBH/w  
if(nFileLength == -1) rj!0GI  
{ 1'?4m0W1  
System.err.println("File Length is not known!"); utr:J  
} Y))NK'B5  
else if(nFileLength == -2) J=/5}u_gw  
{ *2jK#9"MP  
System.err.println("File is not access!"); r&FDEBh  
} Yw0[[N<SW  
else Ewg:HX7<(  
{ R##~*>#  
for(int i=0;i<nStartPos.length;i++) mc4i@<_
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{ %.Q !oYehj  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); {z|;Xi::"  
} .`&F>o(A  
for(int i=0;i<nEndPos.length-1;i++) 5ZBKRu  
{ AlJ} >u  
nEndPos = nStartPos[i+1]; r(9~$_(vK  
} XVU2T5s}  
nEndPos[nEndPos.length-1] = nFileLength; kZ"BBJ6w  
} R LD`O9#j  
} Z(Jt~a3o  
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//启动子线程 K$d$m <  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; /&4U6a  
for(int i=0;i<nStartPos.length;i++) ={u0_j W  
{ ~y7jCcd`  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m4*@o?Ow  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), G z)NwD  
nStartPos,nEndPos,i); 2it?$8#i  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3h<,  
fileSplitterFetch.start(); ]kboG%Dl?9  
} RD.V'`n"  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), I|Gp$uq _  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Rn@#d}  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", A~mum+[5  
nEndPos = " + nFileLength); #Skv(IL  
// fileSplitterFetch[nPos.length-1].start(); M'/aZ# b  
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//等待子线程结束 n93=8;&  
//int count = 0; 9YBv|A  
//是否结束while循环 aFLO{tr`  
boolean breakWhile = false; 5scEc,JCi  
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while(!bStop) Qa.uMq  
{ &y#r;L<9  
write_nPos(); /soKucN"h  
Utility.sleep(500); #BSTlz  
breakWhile = true; )(@Hd  
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for(int i=0;i<nStartPos.length;i++) @/1w4'M  
{ iJ~Vl"|m  
if(!fileSplitterFetch.bDownOver) D:K4H+ch  
{ nWHa.H#  
breakWhile = false; =lpQnj
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break; @K!&qw  
} !Ta>U^7  
} 1</kTm/Qa  
if(breakWhile) [ I/<_AT#  
break; `[n("7,  
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)K2HK&t:  
//count++; h*<P$t  
//if(count>4) ?y!E-&  
// siteStop(); w[ ~#av9  
} 6VhjJJ  
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System.err.println("文件下载结束！"); !e?.6% %   
} 7t*"%]o  
catch(Exception e){e.printStackTrace ();} c?@T1h4  
} OiP!vn}k  
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//获得文件长度 4f;HQ-Iv  
public long getFileSize() NhYLtw^u  
{ Q6r7.pk"SU  
int nFileLength = -1; pn^ d]rou?  
try{ rX1QMR7?  
URL url = new URL(siteInfoBean.getSSiteURL()); nt@aYXK4|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T|TO}_x  
httpConnection.setRequestProperty("User-Agent","NetFox"); +="e]Yh;  
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int responseCode=httpConnection.getResponseCode(); @qHNE,K  
if(responseCode>=400) 6!(@@^7{*  
{ Q0ON9gqqv  
processErrorCode(responseCode); \0gM o&  
return -2; //-2 represent access is error #KiRfx4G  
} }3L@J8:D"  
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String sHeader; jXMyPNTK  
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for(int i=1;;i++) *~x/=.}  
{ 0/oyf]HR  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9,"L^W8"k  
//Utility.log(in.readLine()); ,11H.E Z  
sHeader=httpConnection.getHeaderFieldKey(i); *C:|X b<9  
if(sHeader!=null) +PuPO9jKO@  
{ #&7}-"Nd  
if(sHeader.equals("Content-Length")) 2m2;t0  
{ =7o"
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?%y?rk <  
break; ) v,:N.@Q  
} Ck|8qUz-  
} L;f!.FX#  
else E\4 +_L_j  
break; = MOj|NR [  
} yT,.z 0  
} ok4@N @  
catch(IOException e){e.printStackTrace ();} 1{r)L{]  
catch(Exception e){e.printStackTrace ();} EB8\_]6XJ  
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Utility.log(nFileLength); .?Gd'Lp  
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return nFileLength; #
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} aqc?pqM  
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//保存下载信息（文件指针位置） E0?iXSJ  
private void write_nPos() ])!o5`ltZ  
{ a0ObBe'
  
try{ ;{"+g)u  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 81i655!Z  
output.writeInt(nStartPos.length); L# 2+z@g  
for(int i=0;i<nStartPos.length;i++) 7fba-7-P  
{ w2'f/  
// output.writeLong(nPos);  pn5Q5xc  
output.writeLong(fileSplitterFetch.nStartPos); K]0JC/R6(@  
output.writeLong(fileSplitterFetch.nEndPos); `u&Zrdr,  
} gjAIEI  
output.close(); ixT:)|'i  
} EL9
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catch(IOException e){e.printStackTrace ();} B,=H
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catch(Exception e){e.printStackTrace ();} /x1![$oC0  
} fk x \=  
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L');!/:  
//读取保存的下载信息（文件指针位置） :d#VE-e  
private void read_nPos() AQiwugs  
{ eXf22;Lz  
try{ b8LLr;oQw  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); y`XU~B)J1  
int nCount = input.readInt(); wLOB}ZMT  
nStartPos = new long[nCount]; 9^G/8<^^>  
nEndPos = new long[nCount]; Aw5HF34J  
for(int i=0;i<nStartPos.length;i++) S :<Nc{C  
{ Gnq?"</  
nStartPos = input.readLong(); }=]M2}  
nEndPos = input.readLong(); 3S}Pm2D2  
} w_{wBL[3e  
input.close(); hK,Sf ;5V  
} pj?f?.^  
catch(IOException e){e.printStackTrace ();} 7w6cwHrL@  
catch(Exception e){e.printStackTrace ();} Evjj"h&0J  
} ~15N7=wCM  
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private void processErrorCode(int nErrorCode) De(Hw& IV  
{ x}"uZ$g  
System.err.println("Error Code : " + nErrorCode); %YC_Se7  
} W|g4z7Pb  
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//停止文件下载 /Id%_,}Kb  
public void siteStop() [.uG5%fa  
{ K8UP,f2  
bStop = true; %*0^0wz  
for(int i=0;i<nStartPos.length;i++) 8Y7Q+p|O  
fileSplitterFetch.splitterStop(); >^*+iEe  
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} @3C>BLI8+  
} =t H:,SH  
//负责部分文件的抓取 5?F__Hx*2  
**FileSplitterFetch.java jGpN,/VQa  
*/ Tw;3_Lj  
package NetFox; ([m mPyp>L  
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import java.io.*; ;CPr]avY  
import java.net.*; [J4gH^Z_  
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public class FileSplitterFetch extends Thread { )]H-BIuGm  
r'HtZo$^R  
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String sURL; //File URL e3nYbWBy]  
long nStartPos; //File Snippet Start Position P>NF.BCq  
long nEndPos; //File Snippet End Position g9Xu@N;bL  
int nThreadID; //Thread's ID K+3IWZ&+dG  
boolean bDownOver = false; //Downing is over 9{5&^RbCp  
boolean bStop = false; //Stop identical [nrYpb4  
FileAccessI fileAccessI = null; //File Access interface C8V/UbA /  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 'z%o16F)L  
{ <YhB8W9 P  
this.sURL = sURL; ZL&g_jC  
this.nStartPos = nStart; W;!}#o|%s  
this.nEndPos = nEnd; K,:cJ  
nThreadID = id; ]);%wy{Ho  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 uP~@U"!  
} Vt".%d/`7  
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public void run() {pnS Q  
{ 3@M|m<_R$  
while(nStartPos < nEndPos && !bStop) { + Zd*)M[  
{ Pa V@aM~3  
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try{ B1>/5hV}  
URL url = new URL(sURL); 8TLgNQP
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); z6
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httpConnection.setRequestProperty("User-Agent","NetFox"); (nlvl?\d  
String sProperty = "bytes="+nStartPos+"-"; XF;ES3 d  
httpConnection.setRequestProperty("RANGE",sProperty); Of[XKFn_  
Utility.log(sProperty); 3TY5;6  
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InputStream input = httpConnection.getInputStream(); `Nb[G)Xh  
//logResponseHead(httpConnection); XkXHGDEf1  
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@,cowar*  
byte[] b = new byte[1024]; ,D]QxbwZ  
int nRead; pgE}NlW  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) v*
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{ LSGB
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nStartPos += fileAccessI.write(b,0,nRead); B&[M7i  
//if(nThreadID == 1) W;'!g
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); VcSVu  
} \KQ71yqY  
+zaA,e?\  

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Utility.log("Thread " + nThreadID + " is over!"); b\$}>O  
bDownOver = true; Rv$[)`&T  
//nPos = fileAccessI.write (b,0,nRead); clL2k8VS  
} qB0E_y)a  
catch(Exception e){e.printStackTrace ();}
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} d4>Z8FF|1B  
} Ay5i+)MD  
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*n 6s.$p)%  
//打印回应的头信息 $c:ynjL|P-  
public void logResponseHead(HttpURLConnection con) Vzdh8)Mu\  
{ #Ssx!+q?  
for(int i=1;;i++) mpuq 9)6  
{ YaKeq5%y  
String header=con.getHeaderFieldKey(i); TgmnG/Z  
if(header!=null) ;CmS ~K:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); s;S?;(QI  
Utility.log(header+" : "+con.getHeaderField(header)); XWS%zL
aK  
else j/r]wd"aUS  
break; w$z}r  
} g
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} BF
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public void splitterStop() i
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{ oASY7k_3  
bStop = true; 7w'wjX-  
} f!s=(H;  
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} p?B=1vn-2  
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'yL%3h _@  
/* LL2=&VK  
**FileAccess.java QA<Jr5Ys  
*//文件访问(定位，写) Zrvz;p@~  
package NetFox; cm?\ -[cV  
import java.io.*; ~kZ G{  
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*Eo?k<:zPm  
public class FileAccessI implements Serializable{ MrDc$p W G  
@&1ZB6OCb:  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 G*-b}f
 
RandomAccessFile oSavedFile; BaSZ71>9]r  
long nPos; SzjkI+-$:  
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my}
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public FileAccessI() throws IOException z"0I>gl  
{ B5X(ykaX~  
this("",0); <-[wd.M_  
} *q()f\  
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public FileAccessI(String sName,long nPos) throws IOException }[4r4 1[  
{ 7PtN?;rP  
oSavedFile = new RandomAccessFile(sName,"rw"); F;+|sMrq  
this.nPos = nPos; h&--,A >  
oSavedFile.seek(nPos); w]]8dz  
} Cn "s
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8$0rR55  
public synchronized int write(byte[] b,int nStart,int nLen) ^-,xE>3o  
{ qYlhlHD  
int n = -1; /+@p7FqlE  
try{ %O!v"Xh  
oSavedFile.write(b,nStart,nLen); ;4.!H,d  
n = nLen; Bh;7C@dq  
}
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catch(IOException e) v"#mzd.tW  
{ kic/*v\6@  
e.printStackTrace (); J/[=p<I)  
} Jo@|"cE=  
@te
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return n; $shoasSuI  
} \lZf<f  
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} &N
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/* cm&I* 0\  
**SiteInfoBean.java ] :BX!<  
*/ i`dCG[  
package NetFox; ;|vpwB@B
 
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public class SiteInfoBean { f]JM /  
=jX8.K4]  
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private String sSiteURL; //Site's URL 1e&QSzL  
private String sFilePath; //Saved File's Path .zn;:M#T  
private String sFileName; //Saved File's Name iy14mh\ ~  
private int nSplitter; //Count of Splited Downloading File Y6Lf@}2(i  
f"u%J/e&  
^!9~Nwn  
public SiteInfoBean() rz@=pR :  
{//nSplitter的缺省值为5 QrYpZZ;  
//default value of nSplitter is 5 kX>f^U{j  
this("","","",5); YEj8S5"Su\  
} JWMpPzs  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) K)\M5id]  
{ TW[_Ko86  
sSiteURL= sURL; Mi/&f   
sFilePath = sPath; r9 !Tug*>m  
sFileName = sName; yp66{o  
this.nSplitter = nSpiltter; 7D!u1?]d{  
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} `.x Fiyc  
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public String getSSiteURL() z&{5;A}Q@  
{ *7h!w!LN~  
return sSiteURL; il \$@Bn  
} dO4
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public void setSSiteURL(String value) -mRA#  
{ US%
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sSiteURL = value; ;uW}`Q
<  
} hb^7oq"a  
^",ACWF4Sk  
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public String getSFilePath() T+<A`k: -  
{ bIEhgiH  
return sFilePath; ngat0'oa  
} sRrzp=D  
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public void setSFilePath(String value) ODC8D>Z
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{ cg*)0U-_(  
sFilePath = value; "B8"_D&  
} W@Lu;g.Yc  
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public String getSFileName() TM|)Ljm  
{ ?zsB6B?
;  
return sFileName; v0ES;  
} ^>N]H>0'S  
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public void setSFileName(String value) y
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{ ulER1\W  
sFileName = value; i6 (a@KRY  
} u*#ZXW  
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public int getNSplitter() S.d^T](  
{ zKsz*xv6b  
return nSplitter; *mMEl]+  
} o,!T2&}  
,+ #6Y_  
}QsZ:J.  
public void setNSplitter(int nCount) 0`I-2M4F*Q  
{ QEu=-7@>  
nSplitter = nCount; "n=vN<8(o  
} QlHd,w  
} n9\]S7]52  
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/* &%_& 8DkG  
**Utility.java vUnRi=:|  
*/ WMBm6?54  
package NetFox; bug Ot7  
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public class Utility { 6O22P?v  
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public Utility() 1<<kA:d  
{ e[Jem5C  
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ad_`x  
}
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q;:6_Qr  
//线程睡眠 V`-vR2(  
public static void sleep(int nSecond) @YH+cG|  
{ ~6I)|^Z  
try{ @Kgl%[NmX  
Thread.sleep(nSecond); ne>g?"Pex{  
} D>!6,m2  
catch(Exception e) ,\aUq|~  
{ Jz!Z2c  
e.printStackTrace (); %,iIpYx  
} u?[ q=0.J7  
} ZK'-U,Y.H7  
uyF|O/FC  
//日志 > QFHm5Jw  
public static void log(String sMsg) _NcYI  
{ EOoZoVdzx  
System.err.println(sMsg); [,aqQ6S  
} "aF8l<1xn  
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public static void log(int sMsg) O3.C:?;x  
{ ,b$2=JO'f  
System.err.println(sMsg); =ORf%f5"'  
} R4<lln:[  
} sgr=w+",Q  
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/* ./p|?pu  
**TestMethod.java Q8MS,7y/  
*/ ==cd>03()  
package NetFox; {NCF6Mk  
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public class TestMethod { X[W]=yJJ  
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public TestMethod() 5=KF!?  
{ ///xx/weblogic60b2_win.exe g8'DoHJ*  
try{ ^I]{7$6^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); I|/'Ds:  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5v^L9!`@%v  
SiteFileFetch fileFetch = new SiteFileFetch(bean); E:nt)Ef,  
fileFetch.start(); A7P`lJgv  
} zx1:`K0bi  
catch(Exception e){e.printStackTrace ();} eu'1H@vX(  
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} Z v0C@r  
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public static void main(String[] args) 5% nt0dc  
{ 3hq1yyec  
new TestMethod(); 0W>9'Rw  
} +ySY>`1k~  
} &HM-g7|C0E  
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