http断点续传简单实现（java)

/* 4s-!7  
**SiteFileFetch.java 9{l}bu/u  
*/ nlP;nlW  
package NetFox; ~ljXzD93Z  
import java.io.*; 0J9x9j`&j  
import java.net.*; lA]8&+,
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public class SiteFileFetch extends Thread { HJ"GnZp<  
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SiteInfoBean siteInfoBean = null; //文件信息Bean /v{I  
long[] nStartPos; //开始位置 )nkY_'BV  
long[] nEndPos; //结束位置 4(+PD&_J  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 y(#e}z:  
long nFileLength; //文件长度 D*jM1w_`  
boolean bFirst = true; //是否第一次取文件 04ui`-c(  
boolean bStop = false; //停止标志 K;?+8(H  
File tmpFile; //文件下载的临时信息 H_a[)DT  
DataOutputStream output; //输出到文件的输出流 VA%J\T|G2\  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类）  B,@i  
public SiteFileFetch(SiteInfoBean bean) throws IOException z/-=%g >HA  
{ d]9z@Pd
 
siteInfoBean = bean; 2/?|&[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ch]IzdD  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Q &
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if(tmpFile.exists ()) Oketwa  
{ J.a]K[ci  
bFirst = false; x2xRBkRg=  
read_nPos(); V3Bz Mw\9r  
} [agMfn  
else _BufO7`.  
{ YK_7ip.a[  
nStartPos = new long[bean.getNSplitter()]; 5BIY<B+i  
nEndPos = new long[bean.getNSplitter()]; U^PgG|0N  
} dtDFoETz  
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} =;L|gtH"  
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public void run() VbYdZCC  
{ )%TmAaj9d  
//获得文件长度 F,kZU$  
//分割文件 mH(:?_KrS-  
//实例FileSplitterFetch zLQx%Yg!  
//启动FileSplitterFetch线程 }MySaL>  
//等待子线程返回 >*bvw~y,  
try{ ".%k6W<n  
if(bFirst) g)-te+
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{ 5P bW[  
nFileLength = getFileSize(); PCA4k.,T  
if(nFileLength == -1) mFeP9MfJ  
{ 3]hWfj1m2  
System.err.println("File Length is not known!"); :FF=a3/"6  
} ?6!LL5a.  
else if(nFileLength == -2) %#+Hl0,Tt  
{ vN $s|R'@  
System.err.println("File is not access!");  7GGUV  
} (Ldi|jL  
else I
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{ )J |6-C  
for(int i=0;i<nStartPos.length;i++) TeQV?ZQ#}  
{
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); DU^loB+  
} P?<y%c<  
for(int i=0;i<nEndPos.length-1;i++) , gHDx  
{ _1^'(5f$  
nEndPos = nStartPos[i+1]; y_,bu^+*  
} YSMAd-Ef-  
nEndPos[nEndPos.length-1] = nFileLength; z:O8Ls^\T  
} )7@0[>  
} )oZ dj`  
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//启动子线程 9WHddDA  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; HW|IILFB
 
for(int i=0;i<nStartPos.length;i++) AA_%<zK  
{ 7)m9"InDI  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), b>k y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :UdF  
nStartPos,nEndPos,i); }Z>)DN=+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `oJ [u:b  
fileSplitterFetch.start(); 2%1hdA<  
} pAEx#ck  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :k"]5>(^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", s2?&!  
nEndPos = " + nFileLength); L];b<*d  
// fileSplitterFetch[nPos.length-1].start(); Ac6=(B  
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*:
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//等待子线程结束 YIE<pX4Q7)  
//int count = 0; 9uY'E'm*  
//是否结束while循环 Tw% 3p=  
boolean breakWhile = false; 6~{C.No}  
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while(!bStop) J4utIGF  
{ 6zkaOA46V  
write_nPos(); B!yr!DW
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Utility.sleep(500); dx]>(e@(t{  
breakWhile = true; /?!u{(h}  
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for(int i=0;i<nStartPos.length;i++) ex|F|0k4}  
{ n%-0V>  
if(!fileSplitterFetch.bDownOver)
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{ l%ZhA=TKQ  
breakWhile = false; J1kM\8%b\  
break; IID5c" oR  
} )Z$!PqRw@u  
} 67TwPvh  
if(breakWhile) >/\'zi]L  
break; Si,6o!0k  
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B *v
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//count++; $(9U@N9E  
//if(count>4) !W0v >p  
// siteStop(); \jA~9  
} +"(jjxJm  
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System.err.println("文件下载结束！"); S'14hk<  
} Qd6FH2Pl  
catch(Exception e){e.printStackTrace ();} WHI`/FM  
} +V+a4lU14  
/=h` L,  
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//获得文件长度 {$r[5%L\H  
public long getFileSize() 5IN(|B0  
{ F?cK-.  
int nFileLength = -1; }Lv;

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try{ DMS!a$4  
URL url = new URL(siteInfoBean.getSSiteURL()); *H122njH+T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F/Pep?'  
httpConnection.setRequestProperty("User-Agent","NetFox"); OZT.=^:A  
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int responseCode=httpConnection.getResponseCode(); fh{`Mz,o  
if(responseCode>=400) i!cCMh8  
{ p7Cs.2>M>S  
processErrorCode(responseCode); ~Z
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return -2; //-2 represent access is error KG@8RtHsQ  
} m,S{p<-h  
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String sHeader; j9,P/K$:w  
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for(int i=1;;i++) P$sxr  
{ {T8Kk)L  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); m68*y;#  
//Utility.log(in.readLine()); V:27)]q  
sHeader=httpConnection.getHeaderFieldKey(i); S$k&vc(0  
if(sHeader!=null) jtc~DL  
{ K>9 ()XT)  
if(sHeader.equals("Content-Length")) OH"XrCX7n  
{ uocGbi:V';  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); kl,3IKHa  
break; s7EinI{^  
} L(o15  
} e*!kZAf  
else ?8 {"x8W;  
break; <X5fUU"+U  
} 4sM.C9W  
} Mq8L0%j  
catch(IOException e){e.printStackTrace ();} 
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catch(Exception e){e.printStackTrace ();} ?}7p"3j'z  
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Utility.log(nFileLength); 7?t6UPf  
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return nFileLength; Gy)@Is9  
} '2O\_Uz  
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//保存下载信息（文件指针位置） f-2c0Bi  
private void write_nPos() tjnIN?YT  
{ 80;(Gt@<"  
try{ 8V(pugJ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); PVOv[%  
output.writeInt(nStartPos.length); Vg23!E  
for(int i=0;i<nStartPos.length;i++) - YV>j  
{ .mAjfP*  
// output.writeLong(nPos); G\?YK.Y>  
output.writeLong(fileSplitterFetch.nStartPos); "]iB6  
output.writeLong(fileSplitterFetch.nEndPos);
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} 5-G@L?~Vw  
output.close(); j7c3(*Pl  
} wPl%20t  
catch(IOException e){e.printStackTrace ();} pmilrZmm]  
catch(Exception e){e.printStackTrace ();} 2"5v[,$1H  
} :Yks|VJ1  
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//读取保存的下载信息（文件指针位置） %IRi1EmN8  
private void read_nPos() o]:9')5^  
{ HmwT~  
try{ D0q":WvE  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); |I|fMF2K  
int nCount = input.readInt(); 9,tej  
nStartPos = new long[nCount]; *,m;  
nEndPos = new long[nCount]; XrPfotj1  
for(int i=0;i<nStartPos.length;i++) F>cv<l =6l  
{ @K]|K]cby  
nStartPos = input.readLong(); ]fD} ^s3G  
nEndPos = input.readLong(); 8*fv'  
} :eg4z )  
input.close(); )WoxMmz  
} .6V}3q$-@  
catch(IOException e){e.printStackTrace ();} ^I)N. 5  
catch(Exception e){e.printStackTrace ();} e$pV%5=  
} <9%R\_@$H  
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* H9 8Du  
private void processErrorCode(int nErrorCode) V_:&S2j  
{ :hV7> rr  
System.err.println("Error Code : " + nErrorCode); )0R'(#  
} )Beiu*  
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//停止文件下载 Bw{I;rW{2  
public void siteStop() -GgA&dh  
{ S+2(f> Z  
bStop = true; h*Pc=/p  
for(int i=0;i<nStartPos.length;i++) f`/x"@~H5  
fileSplitterFetch.splitterStop(); ,iq4Iw  
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} yOg+iFTr  
} O#u=c1 ?:  
//负责部分文件的抓取 I9Fr5p-%O  
**FileSplitterFetch.java 9k~8  
*/ ~!3r&(  
package NetFox; PzR[KUK  
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import java.io.*; xRsWI!d+|  
import java.net.*; 6u}</>}  
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public class FileSplitterFetch extends Thread { %!L9)(}"  
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String sURL; //File URL KK%M~Y+tU'  
long nStartPos; //File Snippet Start Position TBrPf-Xr  
long nEndPos; //File Snippet End Position Fr$5RAyg  
int nThreadID; //Thread's ID (@}!0[[^  
boolean bDownOver = false; //Downing is over V#}kwON  
boolean bStop = false; //Stop identical 6Kb1~jY  
FileAccessI fileAccessI = null; //File Access interface 0<B$#8  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException /^
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{ R^e.s -  
this.sURL = sURL; LYg- .~<I  
this.nStartPos = nStart; HX{`VahE  
this.nEndPos = nEnd; w8D"CwS1Rx  
nThreadID = id; XF_pN[}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 lUiL\~Gq  
} f>Jr|#k  
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public void run() 6B ?twh)  
{ 0,8okAH  
while(nStartPos < nEndPos && !bStop) |id <=Xf  
{ j9OG\m  
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try{ Y7[jqb1D  
URL url = new URL(sURL); bD8Gwi=iiu  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P_#bow  
httpConnection.setRequestProperty("User-Agent","NetFox"); (NnH:J`  
String sProperty = "bytes="+nStartPos+"-"; t>B;w14  
httpConnection.setRequestProperty("RANGE",sProperty); <kd1Nrr!p  
Utility.log(sProperty); 9]wN Bd  
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InputStream input = httpConnection.getInputStream(); ")HFYqP>9  
//logResponseHead(httpConnection); ~<OSYb  
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byte[] b = new byte[1024];  {s{j~M  
int nRead; &q|K!5[k  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }XM(:|8J,  
{ x7x\Y(@  
nStartPos += fileAccessI.write(b,0,nRead); H?y,ie#u  
//if(nThreadID == 1) H&}
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ZEO,]$Yi7  
} 0tB0@Wj  
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Utility.log("Thread " + nThreadID + " is over!"); Vr1<^Ib  
bDownOver = true; bB;5s`-  
//nPos = fileAccessI.write (b,0,nRead); r!a3\ep  
} H_<C!OgR  
catch(Exception e){e.printStackTrace ();} Bv%GJ
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} @<]Ekkg  
} Y.ToIka{  
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//打印回应的头信息  XJ5.  
public void logResponseHead(HttpURLConnection con) rkY[E(SY  
{ ^J8lBLqe  
for(int i=1;;i++) ;H.^i|_/  
{ ZH)="qx[  
String header=con.getHeaderFieldKey(i); JNUt$h  
if(header!=null) zeC RK+-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); u4%Pca9(=  
Utility.log(header+" : "+con.getHeaderField(header)); Y6L~K?  
else W$2C47i  
break; oW Nh@C  
} tWa)_y  
} :s6o"VkW  
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t; {F%9j{  
public void splitterStop() 'V=P*#|SR  
{ z4]api(xZ  
bStop = true; jc f #6   
} EeRX+BM,  
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} !*. -`$x  
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/* <r`2)[7N  
**FileAccess.java zY!j:FT1HY  
*//文件访问(定位，写) FfPar:PHj  
package NetFox; k
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import java.io.*; Ab"@714@  
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public class FileAccessI implements Serializable{ }\:NuTf  
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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 iBgx  
RandomAccessFile oSavedFile; "z=SO1  
long nPos; [>%xd)8.c  
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public FileAccessI() throws IOException !~D}/Q;#}\  
{ t*T2Z-!P  
this("",0); }m;,Q9:+m^  
} o-OHjFfB  
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public FileAccessI(String sName,long nPos) throws IOException e`xdSi>E  
{ TS9|a{j3!  
oSavedFile = new RandomAccessFile(sName,"rw"); emPM4iG?!  
this.nPos = nPos; B1C-J/J  
oSavedFile.seek(nPos); d]6#m'U  
} #& Rw&  
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public synchronized int write(byte[] b,int nStart,int nLen) &wCg\j_c  
{ K[r^'P5m  
int n = -1; >X4u]>X  
try{ F!Q@u  
oSavedFile.write(b,nStart,nLen); '*w00  
n = nLen; CtAwBQO  
} u5: q$P  
catch(IOException e) /qGf 1MHD  
{ \2"I;  
e.printStackTrace (); JYd 'Jp8bP  
} 6ne7]RY  
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return n; QpA/SmJ  
} 71gT.E  
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} $#S&QHyEe  
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/* ua]o6GlO  
**SiteInfoBean.java _EMwm&!  
*/ 
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package NetFox; .=;3d~.]  
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public class SiteInfoBean { Yc `)R  
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private String sSiteURL; //Site's URL )V6Hl@v  
private String sFilePath; //Saved File's Path Id|L` w  
private String sFileName; //Saved File's Name C=It* j55  
private int nSplitter; //Count of Splited Downloading File 7/f3Z1g  
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public SiteInfoBean() Dg?70v<a  
{//nSplitter的缺省值为5 JB`\G=PiL  
//default value of nSplitter is 5 .my0|4CQ#@  
this("","","",5); _:C9{aEZb  
} DhT>']Z  
v` 7RCg`  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) PCM-i{6/  
{ *ikc]wQr$  
sSiteURL= sURL; -~ Mb  
sFilePath = sPath; 5Z\#0":e  
sFileName = sName; ws|;`  
this.nSplitter = nSpiltter; &<J[Q%2  
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} /8g^T")  
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public String getSSiteURL() pDcjwlA%  
{ 7cO n9fIE  
return sSiteURL; U($dx.`v#  
} {(wHPzq  
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public void setSSiteURL(String value) W"'iIh)z `  
{ !l 1fIc  
sSiteURL = value; i Ae<&Ms  
} \\7ZWp\fN  
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public String getSFilePath()
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{ J<maQ6p  
return sFilePath; >U*T0FL7  
} ?1$fJ3  
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public void setSFilePath(String value) oMTf"0EIW  
{ JJ'.((  
sFilePath = value; *B{j.{ p(  
} [E JQ>?D  
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public String getSFileName() ICkp$u^  
{ 0B@Jity#!  
return sFileName; aZ'Lx:)R  
} p2udm!)J  
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public void setSFileName(String value) )>-ibf`#?  
{ Zxbq  
sFileName = value; g
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} iN0nw
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public int getNSplitter() $.v5~UGb{\  
{ $K'|0  
return nSplitter; EEZ
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} MR<;i2p  
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public void setNSplitter(int nCount) MFm"G  
{ z`FCs,?K  
nSplitter = nCount; B0WJ/)rK<  
} ez!C?  
} mAW,?h  
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/* hk
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**Utility.java (BfgwC)  
*/ Zg`Mz _?  
package NetFox; S"k*6U  
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public class Utility { X>. NFB  
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public Utility() 9n5<]Q(  
{ (S`2[.j
 
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} 1=a>f"cyf  
+_xOLiu  
//线程睡眠 A7`1-#  
public static void sleep(int nSecond) UaViI/ks  
{ {TRsd  
try{ e$uiJNS2  
Thread.sleep(nSecond); XNb ZNaAd  
} F.=Bnw/-  
catch(Exception e) RxN,^!OV  
{ SdwS= (e6  
e.printStackTrace (); b-*3 2Y%  
} ^ Dt#$Z  
} lmSo8/%T  
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//日志 9{8GP  
public static void log(String sMsg) $gM8{.!  
{ <K4,7J$}h  
System.err.println(sMsg); ZzBQe  
} STw#lU) %(  
zf>5,k'x'A  
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public static void log(int sMsg) ~/ilx#d  
{ ^F"iP7   
System.err.println(sMsg); @*DyZB  
} -+em!g'  
} 'EfR|7m  
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/* {E0z@D)U-  
**TestMethod.java LW:LFzp  
*/ D^;*U[F?  
package NetFox; .*JA!B  
zb Z4|_  
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public class TestMethod { _:B1_rz7,  
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5rV((  
public TestMethod() Q9&kJ%Mo  
{ ///xx/weblogic60b2_win.exe 3QOUU,Dt$  
try{ a9?y`{%L  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); FsGlJ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9A7@ 5F  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "h7tnMS  
fileFetch.start(); h<\_XJJ  
} H<G4O02i_  
catch(Exception e){e.printStackTrace ();} (x$9~;<S*d  
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KB!|B.ChN(  
} ;eZ#bjw-d  
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public static void main(String[] args) OLj\-w^  
{ nPgeLG"00  
new TestMethod(); aRJ>6Q}  
} ?P7]u>H  
} <(e8sNe  
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