http断点续传简单实现（java)

/* |||m5(`S  
**SiteFileFetch.java w,X)g{^T  
*/ SHs [te[  
package NetFox; Lc?"4  
import java.io.*; m_Pk$Vwx  
import java.net.*; VQ,5&-9Y3  
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public class SiteFileFetch extends Thread { f,i2U|1pbj  
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SiteInfoBean siteInfoBean = null; //文件信息Bean k-a1^K3  
long[] nStartPos; //开始位置 C+P.7]?&  
long[] nEndPos; //结束位置 rHjDf[5+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 C[<{>fl)  
long nFileLength; //文件长度 'zav%}b]L  
boolean bFirst = true; //是否第一次取文件 p+<qI~  
boolean bStop = false; //停止标志 p2Gd6v.t  
File tmpFile; //文件下载的临时信息 1) K<x  
DataOutputStream output; //输出到文件的输出流 x${C[gxq9F  
xI<B)6D;f  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &OZx!G^Z  
public SiteFileFetch(SiteInfoBean bean) throws IOException :-#7j} R&  
{ <{8x-zbR+  
siteInfoBean = bean; "=n%L +6%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); M"W#_wY;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); BKO^ux%  
if(tmpFile.exists ()) )b (+=  
{ \BH?GMoP  
bFirst = false; W!T[ ^+  
read_nPos(); ob8}v*s  
} r>! @Z2%s  
else (1q
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{ ftcLP  
nStartPos = new long[bean.getNSplitter()]; Ip`1Wv_  
nEndPos = new long[bean.getNSplitter()]; 5x|$q
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} b$0;fEvIJn  
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} y`8U0TE3R  
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public void run() Du +_dr^4  
{ Z2@e~&L  
//获得文件长度 fd #QCs  
//分割文件 'hPW#*#W<  
//实例FileSplitterFetch g]JRAM  
//启动FileSplitterFetch线程 GFE3p  
//等待子线程返回 GOGS"q  
try{ Tc!n@!RA|  
if(bFirst) *~4<CP+"0  
{ ~8UMw
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nFileLength = getFileSize();  AV|:v3  
if(nFileLength == -1) {X2uFw Gi  
{ 5D=U.UdR  
System.err.println("File Length is not known!"); ]@cI_n  
} d&L  
else if(nFileLength == -2) r_+!3   
{ olr#
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System.err.println("File is not access!"); N.+A-[7,W  
} 5#x[rr{^*  
else 9>0OpgvC(  
{ KztQT9kY  
for(int i=0;i<nStartPos.length;i++) Sh5)36  
{ h5T~dGRlR  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0}`.Z03fy  
} [_`yy  
for(int i=0;i<nEndPos.length-1;i++) !-n*]C  
{ >);M\,1\I  
nEndPos = nStartPos[i+1]; sw}^@0ua=  
} ^i8biOSZu  
nEndPos[nEndPos.length-1] = nFileLength; rN7JJHV  
} )g?jHm-p\  
} "M+I$*]  
\v+c.  
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//启动子线程 v!DK.PZbi  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; OGLA1}k4  
for(int i=0;i<nStartPos.length;i++) G5OGyQp  
{ qhG2j;  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mJd8?d  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4;)t\9cy_  
nStartPos,nEndPos,i); %"oGJp  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G;#xcld  
fileSplitterFetch.start(); DF-PBVfpu  
} T`j{2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 55TFBDc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); pO fw *lD  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Het>G{  
nEndPos = " + nFileLength); 6C<GYzzo  
// fileSplitterFetch[nPos.length-1].start(); %XBTN  
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a
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//等待子线程结束 >dgq2ok!u  
//int count = 0; ar 
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//是否结束while循环 _qk&W_u  
boolean breakWhile = false; \(=xc2  
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while(!bStop) IO7gq+  
{
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write_nPos(); k^ fW/  
Utility.sleep(500); *' es(]W  
breakWhile = true; q9VBK(,X  
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for(int i=0;i<nStartPos.length;i++) |{-?OOKj  
{ ^x/D8M  
if(!fileSplitterFetch.bDownOver) })kx#_o]'d  
{ 1ljcbD)T;  
breakWhile = false; )+Z.J]$O-  
break; b&QI#w  
} SYQP7oG9oQ  
} C2zKt/)A  
if(breakWhile) FYu30  
break; qf ]le]J  
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//count++; vaHtWz!P  
//if(count>4) Uc,

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// siteStop(); |9.J?YP8 (  
} _I3"35a  
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System.err.println("文件下载结束！"); 2'OY,Ooe  
} (E,[Ad,$  
catch(Exception e){e.printStackTrace ();} Unq~lt%2  
} }M"])B I  
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//获得文件长度 Y}q~Km  
public long getFileSize() W?!rqo2SP  
{ K5^zu`19  
int nFileLength = -1; LH @B\ mS  
try{ 9M1DE  
URL url = new URL(siteInfoBean.getSSiteURL()); .q:6F*,1M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |=~mRqG  
httpConnection.setRequestProperty("User-Agent","NetFox"); Hd7Vp:KM  
v$JW7CKA  
v+trHdSBYE  
int responseCode=httpConnection.getResponseCode(); t;PG  
if(responseCode>=400) 8'qlg|{!~  
{ &w`Ho)P  
processErrorCode(responseCode); (Uu5$q(  
return -2; //-2 represent access is error eTw9c }[  
} ieWXr4@:  
,!,M'<?"  
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String sHeader; y0?HZ Xq  
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for(int i=1;;i++) iPG:w+G  
{ YSfJUB!I  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); o@[o6.B<  
//Utility.log(in.readLine()); #4"eQ*.*"  
sHeader=httpConnection.getHeaderFieldKey(i); r4X\/  
if(sHeader!=null) 5.oY$tb(  
{ :J x%K  
if(sHeader.equals("Content-Length"))
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{ Ku uiU= (L  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 
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break; )Spa F)N8  
} D^p)`*  
} "cjD-42  
else "
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break; GNB'.tJ:0Y  
} BNb_i H  
} *uccY_  
catch(IOException e){e.printStackTrace ();} 2~ETu&R:  
catch(Exception e){e.printStackTrace ();} ]c|JxgU  
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Utility.log(nFileLength); q|s:&&Wf  
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return nFileLength; }vgM$o  
} s[/d}S@ >  
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//保存下载信息（文件指针位置） saQo]6#  
private void write_nPos() vgg)f~  
{ ,+C?UW  
try{ w}(pc}^U  
output = new DataOutputStream(new FileOutputStream(tmpFile)); =,qY\@fq  
output.writeInt(nStartPos.length); iYw1{U  
for(int i=0;i<nStartPos.length;i++) O*]}0*CT  
{ q;f L@L@-  
// output.writeLong(nPos); 'gD./|Z0  
output.writeLong(fileSplitterFetch.nStartPos); []yIz1P=j  
output.writeLong(fileSplitterFetch.nEndPos); 28+{  
} `fJ;4$4  
output.close(); >f-RzQ k  
} ER[$TH&  
catch(IOException e){e.printStackTrace ();} $3ZQ|X[|+  
catch(Exception e){e.printStackTrace ();} ]]}iSw'  
} 'Ce?!UO  
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//读取保存的下载信息（文件指针位置） -!M>;M@  
private void read_nPos() Q.V@Sawe5  
{ nG?Z* n  
try{ 8NE[L#k  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); H<g8u{ $  
int nCount = input.readInt(); =eDC{/K  
nStartPos = new long[nCount]; u$ o19n  
nEndPos = new long[nCount]; ;yjw(OAI*  
for(int i=0;i<nStartPos.length;i++) I*a.!/$)  
{ Ytqx0  
nStartPos = input.readLong(); Hl{ul'o  
nEndPos = input.readLong(); jJ2{g> P0P  
} xH,e$t#@@~  
input.close(); ^HTvw~]5  
} |m*l/@1  
catch(IOException e){e.printStackTrace ();} 0A8G8^T  
catch(Exception e){e.printStackTrace ();} G@T_o4t  
} a?Y>hvI  
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}"%mP 4]&  
private void processErrorCode(int nErrorCode) ]y$/~(OW  
{ GN5*  
System.err.println("Error Code : " + nErrorCode); %=s2>vv9  
} E6T=lwOZ  
B !
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"^ dMCS@  
//停止文件下载 ]z=dRq  
public void siteStop() N6S@e\*  
{ T0b/txS  
bStop = true; d]sg9`  
for(int i=0;i<nStartPos.length;i++) tF<&R&=  
fileSplitterFetch.splitterStop(); YT)1_>*\  
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} Y(T$k9%}+  
} rF{,]U9`  
//负责部分文件的抓取 [L|vBr  
**FileSplitterFetch.java Zk|PQfi+  
*/ )`gxaT>&l  
package NetFox; H3iYE~^#  
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import java.io.*; t
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import java.net.*; fmLDufx  
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public class FileSplitterFetch extends Thread { dEX67rUj;  
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{`>pigo  
String sURL; //File URL /%{CJ0Y  
long nStartPos; //File Snippet Start Position SF ^$p$mC  
long nEndPos; //File Snippet End Position (58r9WhS  
int nThreadID; //Thread's ID +OSSgY$  
boolean bDownOver = false; //Downing is over j!0-3YKv  
boolean bStop = false; //Stop identical 5;XU6Rz!  
FileAccessI fileAccessI = null; //File Access interface mr]~(]B?r  
*8u<?~9F  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 5~#oQ&  
{ !# xi^I  
this.sURL = sURL; u,`V%J?vW  
this.nStartPos = nStart; a|]}uFr  
this.nEndPos = nEnd; D&],.N  
nThreadID = id; c% ?@3d  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 P/k#([:2  
} G \$x.  
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public void run() 4JH^R^O<n  
{ U:PtRSdn!b  
while(nStartPos < nEndPos && !bStop) _tQM<~Y]u\  
{ l Yj$3  
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2@N-#x'  
try{ X@A8~kj1  
URL url = new URL(sURL); 0juP"v$C>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V9>$M=  
httpConnection.setRequestProperty("User-Agent","NetFox"); VjeF3pmBa  
String sProperty = "bytes="+nStartPos+"-"; T7Ju7_q}  
httpConnection.setRequestProperty("RANGE",sProperty); ~eiD(04^r*  
Utility.log(sProperty); "b)EH/s  
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InputStream input = httpConnection.getInputStream(); qR%as0;  
//logResponseHead(httpConnection); H5jk#
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byte[] b = new byte[1024]; {t]8#[lo  
int nRead; @j(2tJ,w  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) G6\`Iy68/v  
{ S]&aDg1y}  
nStartPos += fileAccessI.write(b,0,nRead); !rZ
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//if(nThreadID == 1) /(%!txSNEt  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); B_3N:K Y 9  
} UzV78^:,iD  
h`p=~u +  
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Utility.log("Thread " + nThreadID + " is over!"); <e@4;Z(h04  
bDownOver = true; l
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//nPos = fileAccessI.write (b,0,nRead); 4#B56f8  
} \
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catch(Exception e){e.printStackTrace ();} (7??5gjh  
} -V'Y
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} |#(y?! A^  
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//打印回应的头信息 ^=gN >xP  
public void logResponseHead(HttpURLConnection con) _+Pz~_+kS  
{ Juk'eH2^s  
for(int i=1;;i++) 5ne&6  
{ | `?J2WGe  
String header=con.getHeaderFieldKey(i); fK^;?4  
if(header!=null) @$~;vS  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~svea>Fmr  
Utility.log(header+" : "+con.getHeaderField(header)); ?ihRt+eR~  
else S++jwP  
break; d^5x@E_Td  
} nM!_C-
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} $?;)uoAg  

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public void splitterStop() n<A<Xj08T9  
{ >52%^ ?  
bStop = true; py%:,hi  
} 8rLhOA  
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} AU8sU?=  
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/* /.t1Ow  
**FileAccess.java kJCeQK:W  
*//文件访问(定位，写) {=MRJg!U  
package NetFox; b4(,ls  
import java.io.*; fBBtS S  
g6OPYUPg  
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public class FileAccessI implements Serializable{ :8A@4vMS)?  
{WTy/$ Qk  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 xg'xuz$U  
RandomAccessFile oSavedFile; 79+i4(H  
long nPos; DjvPeX  
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public FileAccessI() throws IOException )E^Pn|H  
{ wVF qkJ  
this("",0); LMLrH.  
} R}D[ z7  
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p&
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public FileAccessI(String sName,long nPos) throws IOException |z0% q2(  
{ cG1iO:  
oSavedFile = new RandomAccessFile(sName,"rw"); ^W~8)Rbf  
this.nPos = nPos; VU+=b+B~m  
oSavedFile.seek(nPos); w8`B}Dr23  
} jcRe),  
:OA;vp~$x  
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public synchronized int write(byte[] b,int nStart,int nLen) xZVZYvC,t  
{ $dsLU5]1o  
int n = -1; /RWD\u<l  
try{ 4rpry@1  
oSavedFile.write(b,nStart,nLen); Fv:x>qZr@  
n = nLen; mA^3?yj  
} D/
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[_  
catch(IOException e) VKSn \HT~  
{ E *782>  
e.printStackTrace (); G\~?.s|^  
} zd{sw}  
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dt/-0~U  
return n; "@t bm[  
} /bLL!nD=^  
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} U6YHq2<  
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/* e2L>"/  
**SiteInfoBean.java `$3ktQ$  
*/ ST,+]p3L(  
package NetFox; .0MY$0s  
pdjRakN  
Y&bO[(>1  
public class SiteInfoBean { .9UrWBW\I  
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tqjjn5!  
private String sSiteURL; //Site's URL 01NP  
private String sFilePath; //Saved File's Path >4os%T  
private String sFileName; //Saved File's Name ,V{Bpr  
private int nSplitter; //Count of Splited Downloading File '-3K`[  
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public SiteInfoBean() 3Zwhv+CP[  
{//nSplitter的缺省值为5 _9?v?mL5;  
//default value of nSplitter is 5 5f2=`C0_  
this("","","",5);  \+:`nz3m  
} $f>(T
W  
:SY,;..3e  
^)h&s*  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) +{#Z^y6&  
{ KEf1GU6s  
sSiteURL= sURL; ;j+*}|!  
sFilePath = sPath; xc7Rrh]}  
sFileName = sName; '}-QZ$|*  
this.nSplitter = nSpiltter; 9WV8ZP  
PH'n`
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*e:2iM)8~  
} 4
 []!Km  
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UL  
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public String getSSiteURL() pimI)1 !$'  
{ MPF({Pnx7  
return sSiteURL; x6
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} 9#kk5)J  
O'QnfpQ*9  
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public void setSSiteURL(String value) PF+Or  
{ 9D;
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sSiteURL = value; [w)KNl  
} Qh*}v!3Jo  
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public String getSFilePath() - b`
  
{ J/PK#<  
return sFilePath;  '{cF
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} 6rO^ p  
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ft0tRv(s:  
public void setSFilePath(String value) 12Fnv/[n'K  
{ 7uOtdH+  
sFilePath = value; 6z'0fi|EN  
} 77j"zr7v  
?v'CuWS  
_,I~1"  
public String getSFileName() LvU/,.$  
{ 3Q2NiYg3  
return sFileName; 5glEV`.je  
} ch0cFF^]  
`S4G+j>u6  
3K/]{ dkD  
public void setSFileName(String value) vG=Pi'4XXo  
{ =\\rk,F  
sFileName = value; fgHsg@33N  
} "hZ `^"0b  
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$_e{Zv[  
public int getNSplitter() rA@|nL{  
{ jR*iA3LDo  
return nSplitter; }r"E\~E  
} Ok}e|b[D  
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$#wi2Ve=6b  
public void setNSplitter(int nCount) O"_QDl<ya  
{ Lmw)Ts>  
nSplitter = nCount; A{\DzUV9,  
} ::3[H$  
} 4#I=n~8a  
{}=5uU2Tu  
^9YS dFH/  
/* <,H/7Ba  
**Utility.java !#E-p?O.  
*/ >xH?`I7;f  
package NetFox; y5VohVa`  
oe
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public class Utility { |C,]-mJG  
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public Utility() u{dkUG1ia  
{ u/N_62sk5  
dN){w _  
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} MR,A{X  
YeB C6`7y  
//线程睡眠 {yi!vw  
public static void sleep(int nSecond) #kJ8 qN  
{ O.aAa5^uh  
try{ ,V&E"D{u  
Thread.sleep(nSecond); x/0x&la  
} z_8Bl2tl  
catch(Exception e) =CL,+  
{ psS
^  
e.printStackTrace (); $-E<{   
} TQvjU!>  
} LOgB_$9_3  
UA#=K+2  
//日志 `eGp.[ffT  
public static void log(String sMsg) jASK!3pY  
{ `G>|g^6%i  
System.err.println(sMsg); ~u?rjkSFoh  
} vv
 
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SO~pe$c-  
public static void log(int sMsg) Yt r*"-  
{ MJKPpQ(,  
System.err.println(sMsg); .&K?@T4l  
} XD[9wd5w8  
} lHu/pSu@k  
9(bbV5}  
GW9,%}l^;  
/* 9AD0|,g  
**TestMethod.java 4dh>B>Q  
*/ b}N\h<\G  
package NetFox; f_:>36{1^!  
d 5hx%M  
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public class TestMethod { 6\)u\m`7-l  
LD,T$"  
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public TestMethod() ux[13]yY  
{ ///xx/weblogic60b2_win.exe 'qeUI}[  
try{ YT@H^=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); va.Ve# N  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); )P.,h&h/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [c99m:*+  
fileFetch.start(); sr:hRQ27  
} rj<-sfs  
catch(Exception e){e.printStackTrace ();} >waA\C}  
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} ork{a.1-_w  
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public static void main(String[] args) 4&~*;an7  
{ YIYuqtn
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new TestMethod(); >EgMtZ88.<  
} W7IAW7w8U  
} rE\&FVx  
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