http断点续传简单实现（java)

/* p!~1~q
6  
**SiteFileFetch.java }zS5o [OE  
*/ dC8}Ttc}  
package NetFox; ";7xE#jRk  
import java.io.*; O_ZYm{T[7  
import java.net.*; Z:<an+v|5  
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public class SiteFileFetch extends Thread { P[-do  
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SiteInfoBean siteInfoBean = null; //文件信息Bean "/RMIS K[;  
long[] nStartPos; //开始位置 /:Gy .  
long[] nEndPos; //结束位置 5y 5Dn!`  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 VH~YwO!x  
long nFileLength; //文件长度 79cM_O  
boolean bFirst = true; //是否第一次取文件 n
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boolean bStop = false; //停止标志 b>8TH-1t~  
File tmpFile; //文件下载的临时信息 ~@Q]@8Tv\  
DataOutputStream output; //输出到文件的输出流 Vs{\ YfF  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） `Fo/RZOW  
public SiteFileFetch(SiteInfoBean bean) throws IOException '2i !RT-  
{ H8[A*uYL  
siteInfoBean = bean; )qw;KG0F  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ypG*41  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~Gz9pBv1  
if(tmpFile.exists ()) d"miPR  
{ @y~kQ5k  
bFirst = false; f+hHc8g  
read_nPos(); "O0xh_Nr  
} ls&H oJ7  
else M-@X&bm,S  
{ A9 g%>  
nStartPos = new long[bean.getNSplitter()]; mICEJ\`x  
nEndPos = new long[bean.getNSplitter()]; Xpn\TD<_I  
} ^d{5GK'  
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} [RN]?,  
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public void run() -5 PVWL\  
{ wB[f%mHs  
//获得文件长度 oC49c~`8  
//分割文件 ) c\
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//实例FileSplitterFetch pKy4***I3  
//启动FileSplitterFetch线程 ls:oC},p*  
//等待子线程返回 gee~>l  
try{ mc8Q2eQat}  
if(bFirst) =hFY-~U  
{ <MkvlLu((o  
nFileLength = getFileSize(); 0>7Ij7\[8  
if(nFileLength == -1) bA#9'Qu^j  
{ 4xmJQ>/  
System.err.println("File Length is not known!"); gh?[x.U  
} GIxs>E'X  
else if(nFileLength == -2) J'|=J   
{ Y06^M?}  
System.err.println("File is not access!"); S\8v)|Pr  
} pN5kcvQ  
else 7GsKD=bl]  
{ .
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for(int i=0;i<nStartPos.length;i++) VnsV&cx  
{ ;un@E:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); zvdut ,6<  
} I@ueeDY  
for(int i=0;i<nEndPos.length-1;i++) ^_Hf}8H7]  
{ F6[F~^9D  
nEndPos = nStartPos[i+1]; pvyEs|f=%  
} F/5G~17  
nEndPos[nEndPos.length-1] = nFileLength; 
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} $YEm(:v$  
} w/nohZF6H  
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//启动子线程 r3g^0|)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; M.mn9kw`  
for(int i=0;i<nStartPos.length;i++) C(
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{ I!Z`'1"  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5;0w({1l  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), BeVDTk:  
nStartPos,nEndPos,i); JK =A=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xyGwYv>*KO  
fileSplitterFetch.start(); ?/3wO/
7[  
} ?^%[*OCCC!  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R<&Euph  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Z2$_9.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", UGO;5!  
nEndPos = " + nFileLength); xO )c23Z)]  
// fileSplitterFetch[nPos.length-1].start(); M co:eE  
 lrv-[}}  
]H n:c'aT  
//等待子线程结束 larv6ncV  
//int count = 0; _Rii19k  
//是否结束while循环 hUlRtt  
boolean breakWhile = false; ES+CAwqf  
.A< HM}   
['}|#
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while(!bStop) _h-agn4[i  
{ #Zm`*s`  
write_nPos(); Ww-x+U\l  
Utility.sleep(500); ydzsJ+dx  
breakWhile = true; *m"9F'(Sd  
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for(int i=0;i<nStartPos.length;i++) k={D!4kKz  
{ &gXL{cK'%  
if(!fileSplitterFetch.bDownOver) plWNuEW  
{ \|Af26  
breakWhile = false; F|F0#HC ?  
break; W/2y;@  
} MF"*xr v  
} .:j{d}p}  
if(breakWhile) Z3TC
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break; w PR Ns9^  
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//count++; @o0HD
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//if(count>4) \7LL neq  
// siteStop(); Jq` Dvz  
} ~%*l>GkP*  
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System.err.println("文件下载结束！"); \ZcI{t'a  
}
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catch(Exception e){e.printStackTrace ();} ~},H+A!?  
} */K[B(G  
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//获得文件长度 (>0`e8v!  
public long getFileSize() VzSkqWF/"  
{ Zl3l=x h  
int nFileLength = -1; {1)bLG|$  
try{ a^&"gGg  
URL url = new URL(siteInfoBean.getSSiteURL()); zdJPMNHg  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1^$hbRq  
httpConnection.setRequestProperty("User-Agent","NetFox"); @-)S*+8  
: _Y^o  
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int responseCode=httpConnection.getResponseCode(); <.Tllk@r)  
if(responseCode>=400) -J63'bb7oi  
{ &pI\VIx ?  
processErrorCode(responseCode); ;*qXjv& K  
return -2; //-2 represent access is error mdL T7  
} ,$Fh^KNo]  
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String sHeader; <IR@/b!,  
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for(int i=1;;i++) EO+Ix7w  
{ e[x,@P`  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 1<@lM8&.kO  
//Utility.log(in.readLine()); ;L87 %P(.  
sHeader=httpConnection.getHeaderFieldKey(i); 60~*$`  
if(sHeader!=null) MkVv5C  
{ Q']'
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if(sHeader.equals("Content-Length"))
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{ &S.p%Qe"  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); KD#zsL)3  
break; =X'EDw  
} j\KOKvY)  
} <8
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else ~jKIuO/  
break; A["6dbvv  
} !pe[H*Cy  
} Y]R=z*i%  
catch(IOException e){e.printStackTrace ();} b^i$2$9_  
catch(Exception e){e.printStackTrace ();} ?}^ y6  
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Utility.log(nFileLength); .))k
  
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return nFileLength; hDJ+Rk@  
} i]zh8|">  
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//保存下载信息（文件指针位置） hBZh0xy  
private void write_nPos() l+(B~v  
{ o}36bi{  
try{ QncjSaEE  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9%k4Ic%P  
output.writeInt(nStartPos.length); -[=@'NP  
for(int i=0;i<nStartPos.length;i++) 31g1zdT!  
{ JKYtBXOl  
// output.writeLong(nPos); HE4S%#bH>  
output.writeLong(fileSplitterFetch.nStartPos); ctgH/SU  
output.writeLong(fileSplitterFetch.nEndPos); UGOe(JB  
} muK)Yw[#N  
output.close(); qyE*?73W  
} y#ON=8l  
catch(IOException e){e.printStackTrace ();} ' z^v
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catch(Exception e){e.printStackTrace ();} MmfshnTN  
} VF-[O  
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//读取保存的下载信息（文件指针位置）  Mv%B#J  
private void read_nPos() ='/#G0W  
{ 8r.MODZG/  
try{ iQh:y:Jo1&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9zehwl]~  
int nCount = input.readInt(); 3z 5"Ckzb  
nStartPos = new long[nCount]; ]_y;Igaj  
nEndPos = new long[nCount]; :d~&Dt<c  
for(int i=0;i<nStartPos.length;i++) G)5Uiu:^X  
{ K8iQ
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nStartPos = input.readLong(); uvD*]zX  
nEndPos = input.readLong(); FZ% WD@=  
} j]9,yi  
input.close(); J:;nN-\j  
} zt )WX9  
catch(IOException e){e.printStackTrace ();} 6:TA8w|  
catch(Exception e){e.printStackTrace ();} SMm
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} Sj'.)nz>  
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private void processErrorCode(int nErrorCode) P6ugbq[x#e  
{ 0[OlJMVf  
System.err.println("Error Code : " + nErrorCode); sr.!EQ]  
} H,1Iz@W1  
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*5'l"YQ@1  
//停止文件下载 kh*td(pfP9  
public void siteStop() y=WCR*N  
{ SL% Ec%9Y  
bStop = true; FE?^}VH  
for(int i=0;i<nStartPos.length;i++) g>Kh?(  
fileSplitterFetch.splitterStop(); {$-\)K  
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}
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} \E:l E/y  
//负责部分文件的抓取 |Q~5TL>b  
**FileSplitterFetch.java WPNvZg9*c  
*/ ![@\p5-e  
package NetFox; xXc3#n  
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import java.io.*; !p"Ijz5  
import java.net.*; TYr"yZ([
 
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public class FileSplitterFetch extends Thread { SQVyCxcX_  
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String sURL; //File URL n<>/X_m  
long nStartPos; //File Snippet Start Position O0#9D'{  
long nEndPos; //File Snippet End Position 5oIgxy  
int nThreadID; //Thread's ID naKB2y]l  
boolean bDownOver = false; //Downing is over ZvO,1B  
boolean bStop = false; //Stop identical o.
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FileAccessI fileAccessI = null; //File Access interface N,NEg4 q[  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException
rN^P//  
{ T8rf+B/.L  
this.sURL = sURL; /SZg34%  
this.nStartPos = nStart; %phv<AW  
this.nEndPos = nEnd; Fs EPM"&?h  
nThreadID = id; b}#ay2AR
 
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ^iq$zHbc0u  
} {n>W8sN<  
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public void run() FO5'<G-  
{ Hh1OD?N)  
while(nStartPos < nEndPos && !bStop) Pa!r*(M)C  
{ Z,osdF  
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try{ n7S~nk  
URL url = new URL(sURL); c);(+b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); x p#+{}  
httpConnection.setRequestProperty("User-Agent","NetFox"); wN ![SM/+  
String sProperty = "bytes="+nStartPos+"-"; yXx}'=&!0  
httpConnection.setRequestProperty("RANGE",sProperty); ES#K'Lf  
Utility.log(sProperty); <2a7>\74E0  
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InputStream input = httpConnection.getInputStream(); 9H<6k*  
//logResponseHead(httpConnection); &v^LxLt+s  
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byte[] b = new byte[1024]; 3Yd
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int nRead; _YH)E^If  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5!PU+9Kh  
{ e>kw>%3bl9  
nStartPos += fileAccessI.write(b,0,nRead); t3 q0|S
  
//if(nThreadID == 1) ega
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &r;4$7  
} m"!!)
 
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Utility.log("Thread " + nThreadID + " is over!"); 46dh@&U  
bDownOver = true; `q 4%  
//nPos = fileAccessI.write (b,0,nRead); ba3_55]  
} b7/1]  
catch(Exception e){e.printStackTrace ();} uSs~P%@6|  
} .jhuC#x{/  
} +x!V;H(  
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) tGC&l+?/  
//打印回应的头信息 otXB:a  
public void logResponseHead(HttpURLConnection con) }Jgz#d  
{ j`\}xDg  
for(int i=1;;i++) cvbv\G'aT  
{ u8*Uia*vwH  
String header=con.getHeaderFieldKey(i); j+n1k^jC  
if(header!=null) j0k"iv  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); '$M=H.  
Utility.log(header+" : "+con.getHeaderField(header));
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else 33\{S$p  
break; `?Wak=]g  
} d;ElqRC&  
} YXH9Q@Gn  
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public void splitterStop() X+{4,?04+  
{ S*:b\{[f>  
bStop = true; X;T(?,,  
} [t /hjm"$  
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} -lyT8qZ:(  

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/* C}+w<  
**FileAccess.java O~B iqm  
*//文件访问(定位，写) J;+iW*E:  
package NetFox; r}9qK%C G.  
import java.io.*; :a}hd^;[%8  
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public class FileAccessI implements Serializable{ 9xC,i )  
&-9wUZ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 w@4q D  
RandomAccessFile oSavedFile; H__9%p#  
long nPos; ;]MHU/  
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public FileAccessI() throws IOException }V?SedsY  
{ j|KZ HH%dc  
this("",0); |Z$heYP:w  
} mT>56\63  
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public FileAccessI(String sName,long nPos) throws IOException *8fnxWR  
{ #5N#^#r"  
oSavedFile = new RandomAccessFile(sName,"rw"); 93[c^sc9*a  
this.nPos = nPos; bJ]g2C7`36  
oSavedFile.seek(nPos); Ej ip%m  
} l[l('-f  
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public synchronized int write(byte[] b,int nStart,int nLen) !t{3IE  
{ 6?Rm>+2>v  
int n = -1; d /jO~+jP  
try{ MSoLx' <  
oSavedFile.write(b,nStart,nLen); "44VvpQC  
n = nLen; Ja|! fT  
} }?^5\otu  
catch(IOException e) T c4N\Cy  
{ { o=4(RC  
e.printStackTrace (); Z[yQKy  
} hUcG3IOBf  
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return n; ^UZEdR;  
} <K%qaf  
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} AiykIER/  
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/* F"#bCnS  
**SiteInfoBean.java G\?fWqx  
*/ b!J21cg<L  
package NetFox; z[B*sbS  
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public class SiteInfoBean { FylL7n  
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private String sSiteURL; //Site's URL IExo#\0'6  
private String sFilePath; //Saved File's Path <->Nex  
private String sFileName; //Saved File's Name |G~LJsXW!v  
private int nSplitter; //Count of Splited Downloading File )d!,,o  
1hw1AJ}(F  
W
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public SiteInfoBean() 4pq@o  
{//nSplitter的缺省值为5 acz8 H0cS  
//default value of nSplitter is 5 ,di'279|  
this("","","",5); 0
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} Mdsn"Y V  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) SH2|xn  
{ uIvy1h9m  
sSiteURL= sURL; BoE;,s>]NW  
sFilePath = sPath; AC@WhL  
sFileName = sName; T3,"g=  
this.nSplitter = nSpiltter; n#[-1(P  
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uo;aC$US  
} 3JVENn9  
^I=c]D]);  
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public String getSSiteURL() ^AkVmsv;;  
{ Y u\
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return sSiteURL; YjN2 ,Xi  
} ifTMoC%  
+b"RZ:tKp  
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public void setSSiteURL(String value) SIv8EMGo  
{ knrR%e;  
sSiteURL = value;
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} 47>IT  
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public String getSFilePath() GxE"q-G  
{ g^ZsV:D  
return sFilePath; {j i;~9'Q  
} B?`n@/  
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public void setSFilePath(String value) Y^80
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{ [lZo'o  
sFilePath = value; wv0d"PKTS  
} k~f3~-"  
4+%;eY.A  
\?uaHX`1  
public String getSFileName() ,CqJ((  
{ e=K2]Y Q{  
return sFileName; R\k= CoJJ  
} par|j]  
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public void setSFileName(String value) (qd$wv^h  
{ AffVah2o:  
sFileName = value; EQZu-S`kv  
} @V{s'V   

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public int getNSplitter() VK\ Bjru9
 
{ UB[tYZ  
return nSplitter; Hik8u!#P  
} @y:mj \J9  
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public void setNSplitter(int nCount) *:t]|$;E\  
{ ZqKUz5M4  
nSplitter = nCount; 8BZTHlUB  
} 0l-m:6
 
} N)'oX3?x  
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/* 7oY}=281  
**Utility.java xK4b(KJj  
*/ |lH~nU.*  
package NetFox; Z}bUvr XP  
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public class Utility { BM bT:)%  
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i'  
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public Utility() A:Y]<jt  
{ 0Yz &aH  
uv*OiB"  
$47cKit|k:  
} #6g-{OBv  
v~-z["=}!  
//线程睡眠 'Y23U7 n0B  
public static void sleep(int nSecond) l:NEK`>i  
{ KQsS)ju  
try{ U" eP>HHp  
Thread.sleep(nSecond); aYQ!`mS::M  
} 3md yY\+&  
catch(Exception e) G=4Da~<ij  
{ 3UeG>5R  
e.printStackTrace (); uS :3Yo  
} ) *:<3g!  
} YpQ/ )fSEV  
zo66=vE!  
//日志 ?_9cFo59:  
public static void log(String sMsg) #5HJW[9  
{ x#yL&+'?Mj  
System.err.println(sMsg); CL/8p;
  
} EgIFi{q=0  
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public static void log(int sMsg) ^T\JFzV  
{ kE QT[Lo  
System.err.println(sMsg); 'qBg^c  
} 4)Y=)#=  
} "El$Sat`  
vGWX=O  
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/* TL@_m^SM  
**TestMethod.java ?}^e,.M0?s  
*/ bG nBV7b  
package NetFox; Eugt~j3  
-)@DH;[tb  
*=}$@OS  
public class TestMethod { ~V3pj('/)'  
6 )eO%M`  
Uxx=$&#  
public TestMethod() Ty\&ARjb 8  
{ ///xx/weblogic60b2_win.exe c>d+q9M  
try{ {>>ozB.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >L#&L?#  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); pc}Q_~e  
SiteFileFetch fileFetch = new SiteFileFetch(bean); PIP2(-{ai  
fileFetch.start(); VR5$[-E3  
} {/12.y=)~  
catch(Exception e){e.printStackTrace ();} # 4`*`)%  
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2
  
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}  ~d_Z?Z  
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public static void main(String[] args) YcE:KRy  
{ {c
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new TestMethod(); P:t|'t  
} %b'ic  
} Y[Us"K`  
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