http断点续传简单实现（java)

/* ,g}$u'A+d  
**SiteFileFetch.java - EGZ  
*/ M^8zqAA  
package NetFox; F)X`CG ;t  
import java.io.*; Hcg7u7M{  
import java.net.*; S'qT+p
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/ [49iIzC  
public class SiteFileFetch extends Thread { 'dh{q`#0  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ~!2fUewEu  
long[] nStartPos; //开始位置 ;SjNZi)4d  
long[] nEndPos; //结束位置 T]z(>{  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ,G46i)E\  
long nFileLength; //文件长度 aXqig&:  
boolean bFirst = true; //是否第一次取文件 BF2U$-k4  
boolean bStop = false; //停止标志 'Ca;gi !U  
File tmpFile; //文件下载的临时信息 ;b=diZE  
DataOutputStream output; //输出到文件的输出流 Mb[4_D
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） $.
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public SiteFileFetch(SiteInfoBean bean) throws IOException 5EVypw?]x  
{ GVlT+Rs7  
siteInfoBean = bean; :ChXzZ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); a}f/<-L  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7?uDh'utt  
if(tmpFile.exists ()) ]g;+7  
{ =oh%-Sh:  
bFirst = false; XKZsX1=@R  
read_nPos(); ,q#SAZ/N  
} s#aj5_G  
else ~' 955fK>  
{ BQ u
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nStartPos = new long[bean.getNSplitter()]; Gvdok<o  
nEndPos = new long[bean.getNSplitter()]; /
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} :vEfJSA 1<  
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} :w5
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public void run() Y7g%nz[[  
{ ,4'y(X<R  
//获得文件长度 F5YoE
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//分割文件 ?yjg\S?L  
//实例FileSplitterFetch ^&mrY[;S  
//启动FileSplitterFetch线程 H.>EO&#|p  
//等待子线程返回 H<fi,"X^  
try{ # }}6JM  
if(bFirst) ulW>8bW&  
{ Hc>yZ:c;  
nFileLength = getFileSize();
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if(nFileLength == -1) GXD<X_[  
{ n.'Ps+G(  
System.err.println("File Length is not known!"); fa/o4S<  
} ^{=UKf{  
else if(nFileLength == -2) +2eri_p  
{ 9Xa.%vw>  
System.err.println("File is not access!"); . 70=xH  
} W/t,7lPFb  
else c u";rnj  
{ wzxV)1jT  
for(int i=0;i<nStartPos.length;i++) `@1e{?$  
{ T+B-R\@t  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); qyVARy  
} u1UCe  
for(int i=0;i<nEndPos.length-1;i++) (n>Gi;u(R  
{ 6XZjZ*)W  
nEndPos = nStartPos[i+1]; H{N},B  
} XY? Cl  
nEndPos[nEndPos.length-1] = nFileLength; fB7Jx6   
} Owu?ND  
} VO {z)_  
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//启动子线程 ackeq#  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; P`Now7! GW  
for(int i=0;i<nStartPos.length;i++) D
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{ O#[bNLV  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), | Z7j s"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), *JFkqbf  
nStartPos,nEndPos,i); ZQKo ]Kdr  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); JM/\n4ea:  
fileSplitterFetch.start(); &0bq3JGW  
} "HqmS  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rX5"p!z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); }vY^eOK.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ,\&r\!=  
nEndPos = " + nFileLength); z3L=K9)  
// fileSplitterFetch[nPos.length-1].start(); =ca[*0^Z7  
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//等待子线程结束 8`)* ?Q9~  
//int count = 0; 0n
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//是否结束while循环 Gukvd6-g9b  
boolean breakWhile = false; Srmr`[i  
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while(!bStop) DOFW"SpE  
{ p&<n_b  
write_nPos(); CC3i@  
Utility.sleep(500); WW6-oQs_#*  
breakWhile = true; q&9]4j  
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for(int i=0;i<nStartPos.length;i++) ?#&[1.= u  
{ (vD==n9Hd  
if(!fileSplitterFetch.bDownOver) >m!Z$m([J  
{ 0iR?r+|  
breakWhile = false; 3[_WTwX0  
break; J> ,w},`  
} VrfEa d  
} DxN\ H"  
if(breakWhile) cc`u{F9  
break; /&47qU4PJ  
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//count++; +eH`mI0f  
//if(count>4) UeZ(@6_:  
// siteStop(); }dMX1e1h8  
} r 20!  
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System.err.println("文件下载结束！"); MxX)&327  
} <<gW`KF   
catch(Exception e){e.printStackTrace ();} [hot,\+f  
} <wFmfrx+
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//获得文件长度 KTmwkZcfYD  
public long getFileSize()
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{ adri02C/  
int nFileLength = -1; H<ovIMd  
try{ IaRwPDj6  
URL url = new URL(siteInfoBean.getSSiteURL()); WEG!;XZ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); UfO='&U^  
httpConnection.setRequestProperty("User-Agent","NetFox"); &#u\@Qze  
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int responseCode=httpConnection.getResponseCode(); $39TP@?:Z)  
if(responseCode>=400) Dt7z<1-)l  
{ Lh-Y5(c o  
processErrorCode(responseCode); h\Y~sm?
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return -2; //-2 represent access is error
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} ) d'H&c3  
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String sHeader; +.^pAz U}R  
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for(int i=1;;i++) C{t}q*fG 5  
{ M3!;u%~}s  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); G[>CBh5  
//Utility.log(in.readLine()); rbv  
sHeader=httpConnection.getHeaderFieldKey(i); J
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if(sHeader!=null) 3rN}iSF^  
{ L_:~{jV  
if(sHeader.equals("Content-Length")) )`Qr=DIsW  
{ /GJL&RMx  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `\ IaeMvo  
break; `<T4
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} doX`NbA  
} dikX_ Q>D  
else "mU2^4q  
break; LB$0'dZU  
} yD!GgnW  
} 7iv g3*  
catch(IOException e){e.printStackTrace ();} J%q)6&  
catch(Exception e){e.printStackTrace ();} "9Q_lVI|Q  
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Utility.log(nFileLength); Wq1OYZ,  
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return nFileLength; fo>_*6i74  
} @J^ Oy 3z  
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//保存下载信息（文件指针位置） YFj#{C.  
private void write_nPos() \YF;/KwX$  
{ 9[YnY~z)  
try{ h;#^?v!+  
output = new DataOutputStream(new FileOutputStream(tmpFile));

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output.writeInt(nStartPos.length); j3+ hsA/(k  
for(int i=0;i<nStartPos.length;i++) ;.$vDin6  
{ 4wEkxCWp/  
// output.writeLong(nPos); V5 9Vf[i|  
output.writeLong(fileSplitterFetch.nStartPos); `s=Z{bw  
output.writeLong(fileSplitterFetch.nEndPos); 0/z$W.!  
} :]8A;`G}  
output.close(); "9*MSsU  
} `W1TqA  
catch(IOException e){e.printStackTrace ();} c;yp}k]\  
catch(Exception e){e.printStackTrace ();} QiV
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} +yk0ez  
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//读取保存的下载信息（文件指针位置） UIIsgNca  
private void read_nPos() >8vq`,e  
{ CSWA/#&8>  
try{ &i`(y>\  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); wF6a*b@v  
int nCount = input.readInt(); #X{lV]Z  
nStartPos = new long[nCount]; ,ag* /  
nEndPos = new long[nCount]; R Eo{E  
for(int i=0;i<nStartPos.length;i++) ] ONmWo77o  
{ md\Vw?PkU  
nStartPos = input.readLong(); D=5%lL  
nEndPos = input.readLong(); Gw6!cp|/  
} w'xPKO$bzR  
input.close(); 1guiuR4  
} ]D2d=\  
catch(IOException e){e.printStackTrace ();} qI74a F  
catch(Exception e){e.printStackTrace ();} Pum&\.l  
} Y~#.otBL&  
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private void processErrorCode(int nErrorCode) *Kq;xM6Ck  
{ 2`FDY3n  
System.err.println("Error Code : " + nErrorCode); PCc{0Rp\vk  
} D7B g!*  
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//停止文件下载 K}whqe]j  
public void siteStop() Rp_}_hL0  
{ Eh9{n,5-  
bStop = true; l u{6  
for(int i=0;i<nStartPos.length;i++) UhU+vy6)/  
fileSplitterFetch.splitterStop(); -"2
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} AuBBSk8($  
} 00Ye ]j_  
//负责部分文件的抓取 9r
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**FileSplitterFetch.java a?W<<9]  
*/ {G|= pM\'  
package NetFox; H:16aaMn(  
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import java.io.*; mD?={*7%  
import java.net.*; {HVsRpNEf  
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public class FileSplitterFetch extends Thread { criNeKa  
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String sURL; //File URL #%z@yg  
long nStartPos; //File Snippet Start Position 7$"5qJ{s  
long nEndPos; //File Snippet End Position #Qu|9Q[QH  
int nThreadID; //Thread's ID +ul.P)1J6  
boolean bDownOver = false; //Downing is over ,C'mE''x  
boolean bStop = false; //Stop identical `yRt?UQRS  
FileAccessI fileAccessI = null; //File Access interface es$<Vkbp  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @]V_%,  
{ Orlf5{P  
this.sURL = sURL; ExOSHKU,e  
this.nStartPos = nStart; Z?eedVV@  
this.nEndPos = nEnd; 0o 8V8 :  
nThreadID = id; a3 t||@v!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9}G<\y  
} Qb86*  
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public void run() 2P|j<~JS  
{ NV2$ >D  
while(nStartPos < nEndPos && !bStop) OuPfB  
{ 5N2`e3:I  
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try{ A_.}-dzF  
URL url = new URL(sURL); `2G%&R,k"D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); kNrd=s,-]D  
httpConnection.setRequestProperty("User-Agent","NetFox"); J p0j  
String sProperty = "bytes="+nStartPos+"-"; T&E'MB  
httpConnection.setRequestProperty("RANGE",sProperty); &w^:nVgl  
Utility.log(sProperty);
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InputStream input = httpConnection.getInputStream(); pEG!j ~  
//logResponseHead(httpConnection); Tx$bg(  
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byte[] b = new byte[1024]; z{U^j:A
 
int nRead; % )}rQqQ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 4tp}  
{ )u=a+T  
nStartPos += fileAccessI.write(b,0,nRead); c 1{nOx  
//if(nThreadID == 1) #b;TjnC5{$  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 19\ V@d^  
} Z4T{CwD`D  
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Utility.log("Thread " + nThreadID + " is over!"); 6lQP+! EF  
bDownOver = true; .DhB4v&  
//nPos = fileAccessI.write (b,0,nRead); 6eK7Jv\K  
} R)]+>M-.  
catch(Exception e){e.printStackTrace ();} e1R<+`]  
} {"*gX&;~  
} o-<.8Z}>at  
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//打印回应的头信息 mqQC`Aqx:  
public void logResponseHead(HttpURLConnection con) >ZnnGX6$(  
{ N >];xb>  
for(int i=1;;i++) qoC<qn{.a  
{ ,mE}#cyY  
String header=con.getHeaderFieldKey(i); FBA th !E  
if(header!=null) *XG.?%x*|  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); K'U=);W  
Utility.log(header+" : "+con.getHeaderField(header)); L\t?^u  
else AK$i0Rn;pm  
break; }Y3*X:i7  
} fRcy$  
} di~ [Ivw  
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public void splitterStop() 7@!3.u1B  
{ D.x&N~-  
bStop = true; Q
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} " 8g\UR"[  
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} %VO>6iVn  
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/* cx*$GaMk  
**FileAccess.java 5Ln !>,  
*//文件访问(定位，写) )JA^FQ5N  
package NetFox; xbZR/!?  
import java.io.*; T2ZN=)xZ1  
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public class FileAccessI implements Serializable{ vF'Y; M  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 P,K^oz}  
RandomAccessFile oSavedFile; EnYEAjX  
long nPos; ^-qz!ib  
J L2g!n= K  
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public FileAccessI() throws IOException rTA#4.*&  
{ `Wp& 'X  
this("",0); aj$&~-/ R  
} D4U<Rn6N_5  
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public FileAccessI(String sName,long nPos) throws IOException B3&ETi5NTU  
{ S+-V16{i  
oSavedFile = new RandomAccessFile(sName,"rw"); X;yThb`iI  
this.nPos = nPos; SM[VHNr,-  
oSavedFile.seek(nPos); lxtt+R  
} n@//d.T  
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public synchronized int write(byte[] b,int nStart,int nLen) dY.NQ1@"  
{ mZL0<v
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int n = -1; Ihx[S!:  
try{ x8RiYi+  
oSavedFile.write(b,nStart,nLen); e+wIN
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n = nLen; _/h<4G6A  
} a} :2lL%  
catch(IOException e) t^g+nguz  
{ \_t[\&.a}  
e.printStackTrace (); -@mcu{&  
} G,,f' >  
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return n; Ew&|!d  
} @eN,m {b  
 J?qikE&  
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} ;^ YpQP  
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/* q$jwH] .  
**SiteInfoBean.java o
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*/ 3Hhu]5  
package NetFox; iq3TP5%i  
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public class SiteInfoBean { GT-ONwVDq  
VN]"[  
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private String sSiteURL; //Site's URL dIk9C|-.  
private String sFilePath; //Saved File's Path ZtX\E
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private String sFileName; //Saved File's Name Ksvk5r&y  
private int nSplitter; //Count of Splited Downloading File O2oF\E_6  
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public SiteInfoBean() i6xzHfaYG  
{//nSplitter的缺省值为5 G3.\x_;k  
//default value of nSplitter is 5 So}pA2[0  
this("","","",5); $~'G<YYF4  
} Ej$oRo{IG  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) cs)R8vuB)z  
{ qDjH^f  
sSiteURL= sURL; -hZw.eChQa  
sFilePath = sPath; ]t_ Wl1*|  
sFileName = sName; vW5>{
  
this.nSplitter = nSpiltter; |uM(A~?  
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} Xb1is\JB  
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public String getSSiteURL() {5JYu  
{ qex::Qf  
return sSiteURL; +Q+!#  
} c"NGE  
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public void setSSiteURL(String value) SQDc%I>b  
{ r-&* `Jh  
sSiteURL = value; o>
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} b:x*H
jf  
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public String getSFilePath() /1?{,Das=  
{ `k3s
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return sFilePath; Mqm9i  
} Y$
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public void setSFilePath(String value) tCQf `  
{ UX)QdT45Mh  
sFilePath = value; 2o~UA\:+=  
} e(jD[q  
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public String getSFileName() W ZW:q  
{ EP6@5PNZ  
return sFileName; KZ|p_{0&  
} ^-s`$lTp  
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public void setSFileName(String value) W(PNw2  
{ u\=yY.   
sFileName = value; &&te(DC\  
}  pwo @ S"  
- 4B&{P  
2z9N/SyN  
public int getNSplitter() %wIb@km  
{ \Z625jt  
return nSplitter; y1Y  
} __ G=xf  
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&M2fcw?  
public void setNSplitter(int nCount) $K_-I8e|  
{ VQn]"G(`  
nSplitter = nCount; j15t8du&O  
} ;et(Yi;9  
} /mnV$+BE  
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/* !GtCOr\'  
**Utility.java 6jz~q~I  
*/ &a";jO GB  
package NetFox; `5Em: 8 M  
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public class Utility { &;$- &;  
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public Utility() 9HD5A$  
{ d&%}u1 .  
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=[`gfw  
} xWKUti i  
w/Wd^+IIn  
//线程睡眠 `+GiSj8'G  
public static void sleep(int nSecond) p+Icq!aH5  
{
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try{ T0K*!j}O  
Thread.sleep(nSecond); 4,:)%KB"V  
} \w2X.2b.F  
catch(Exception e) {e83 A/{  
{ 4m6%HV8{}[  
e.printStackTrace (); ' y_2"  
} =v~$&@  
} @<44wMp  
Z^GXKOeq  
//日志 h($Jo  
public static void log(String sMsg) DO ,7vMO  
{ tDNo; f  
System.err.println(sMsg); (0zYS_mA  
} l#|M.V6G  
&F|Wk,y  
qQCds}<w  
public static void log(int sMsg) Z/b,aZhB  
{ 2G}@s.iE  
System.err.println(sMsg); ?,
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} }Z% j=c"d  
} wW0m}L  
>TS=tK  
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/* !9EbG  
**TestMethod.java PpR eqmo  
*/ );fPir?+  
package NetFox; Hu$JCB-%  
RH&}'4JE:  
BmCBC,j<v>  
public class TestMethod { qim|=  
5S&^mj-9  
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public TestMethod() k:CSH{s5{  
{ ///xx/weblogic60b2_win.exe SW=%>XKkh  
try{ kI/%|L%6D  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); FO?I}G22  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); p&3~n: Fo  
SiteFileFetch fileFetch = new SiteFileFetch(bean); bE2{^5iG  
fileFetch.start(); A9M/n^61  
} Cj#?Z7}z  
catch(Exception e){e.printStackTrace ();} *jo1?  
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} r8[Ywn<u  
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public static void main(String[] args) UQCond+K  
{ *AA78G|  
new TestMethod(); fDZnC Fa  
} fh@/fd  
} u&$1XZ!es  
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