http断点续传简单实现（java)

/* ^Rm  
**SiteFileFetch.java :Hxv6  
*/ Nn>'^KZNG  
package NetFox; 0"~i^  
import java.io.*; 9@Cv5L?p\  
import java.net.*; 12Y  
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public class SiteFileFetch extends Thread { );-~j  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 5n
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long[] nStartPos; //开始位置 /VG2.:  
long[] nEndPos; //结束位置 6q 2_WX  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 iQ{G(^sZN  
long nFileLength; //文件长度 g^zs,4pPU<  
boolean bFirst = true; //是否第一次取文件 .k,YlFvj  
boolean bStop = false; //停止标志 e%W$*f  
File tmpFile; //文件下载的临时信息 |7x\m t  
DataOutputStream output; //输出到文件的输出流 N&@}/wzZ  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） X$/2[o#g  
public SiteFileFetch(SiteInfoBean bean) throws IOException 7gRgOzWfV  
{ 3_A *$  
siteInfoBean = bean; 4tY ss  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); H#ClIh?'b  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -W>'^1cR  
if(tmpFile.exists ()) -_$$Te  
{ g}]t[}s1]  
bFirst = false; I!^O)4QRx  
read_nPos(); O*#*%RL|  
} 4j)tfhwd8  
else o.I6ulY8  
{ (Cqn6dWK  
nStartPos = new long[bean.getNSplitter()]; hpU2  
nEndPos = new long[bean.getNSplitter()]; 4*$G & TX  
} v$^Z6>vVI  
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} L@fY$Rw  
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public void run() 5eWwgA  
{ ({o'd=nO  
//获得文件长度 4
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//分割文件 NFv>B>  
//实例FileSplitterFetch )2M>3C6>f  
//启动FileSplitterFetch线程 {5  sO  
//等待子线程返回 uG
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try{ 2it?$8#i  
if(bFirst) /t(C>$ }p  
{ }}<z/zN&^  
nFileLength = getFileSize(); o6p98Dpg   
if(nFileLength == -1) A<ynIs<  
{ M'/aZ# b  
System.err.println("File Length is not known!"); i7ly[6{^pr  
} Tyck/ EO  
else if(nFileLength == -2) IH"6? 9nd  
{ G%Lt.?m[  
System.err.println("File is not access!"); $cZUM}@  
} &y#r;L<9  
else ,GgAsj
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{ 9VbOQ{8  
for(int i=0;i<nStartPos.length;i++) \Acqr@D  
{ h?pkE  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); FJd]D[h  
} ZIF49`Y4TF  
for(int i=0;i<nEndPos.length-1;i++) +}a ]GTBgA  
{ .c$316  
nEndPos = nStartPos[i+1]; QNl'ZB\  
} _l1NKk  
nEndPos[nEndPos.length-1] = nFileLength; 9`9R!=NM  
} 5+wAzVA  
} 95
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6VhjJJ  
x@Hc@R<!  
//启动子线程 wT{nu[=GH*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;{[.Zu  
for(int i=0;i<nStartPos.length;i++) &:7ZQ1  
{ _H/8_[xk  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .e3+s*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), SZXY/~=h  
nStartPos,nEndPos,i); [#sz WNfU  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YSe.t_K2C  
fileSplitterFetch.start(); S)/_muP  
} jfqopiSi  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @qHNE,K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $O5UyKI  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", piZJJYv t  
nEndPos = " + nFileLength); 10U9ZC  
// fileSplitterFetch[nPos.length-1].start(); 0xXC^jx:  
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Ho *AAg  
//等待子线程结束 icgSe:Ci  
//int count = 0; xoR;=ph  
//是否结束while循环 }_68j8`  
boolean breakWhile = false; *VZ5B<Ic  
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while(!bStop) .>IhN 5  
{ D=
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write_nPos(); aX}P|l  
Utility.sleep(500); Ez-[ )44/  
breakWhile = true; QD>"]ap,o  
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for(int i=0;i<nStartPos.length;i++) ;y2/-tL?  
{ [E ]E  
if(!fileSplitterFetch.bDownOver) [ra_ 2R  
{ h^o{@/2  
breakWhile = false; {
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break; WpRc)g:  
} 6Avw-}.7>  
} %&Q$dzgb_  
if(breakWhile) =HlQ36;*  
break; }-6)gWe  
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//count++; ZXuv CI  
//if(count>4) H?X|(r|+  
// siteStop(); *9{Z$IA9w  
} HI11Jl}{  
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System.err.println("文件下载结束！"); ]3l
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} N/K.%<h  
catch(Exception e){e.printStackTrace ();} c>)Yt^q&K  
} u!W0P6   
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//获得文件长度 w_{wBL[3e  
public long getFileSize() uvG]1m#  
{ ^kB8F"X  
int nFileLength = -1; VQS~\:1  
try{ o_^?n[4  
URL url = new URL(siteInfoBean.getSSiteURL()); n4#;k=mA  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j+,d^!  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~,B5Hc 2  
{*I``T_+  
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int responseCode=httpConnection.getResponseCode(); 4k@5/5zsM  
if(responseCode>=400) ^8AXxE  
{ K8UP,f2  
processErrorCode(responseCode); )j0TeE1R  
return -2; //-2 represent access is error 6U R2IxbE  
} `6]%P(#a  
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String sHeader; .G#8a1#  
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for(int i=1;;i++) <BMXCk  
{ E{Ov>osq  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \Yc
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//Utility.log(in.readLine()); r'HtZo$^R  
sHeader=httpConnection.getHeaderFieldKey(i); ^!<BQP7  
if(sHeader!=null) m0;CH/D0  
{ 6&!PmKFO.  
if(sHeader.equals("Content-Length")) t7j);W%e6  
{ g|vNhq0|i  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); #\ X#w<\?  
break; rzm:Yx  
} )W;o<:x3  
} {^7Hgg  
else P;qN(2L/=<  
break; c*L0@Ak%  
} AK*LyR?  
} ,P70J
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catch(IOException e){e.printStackTrace ();} CkoLTY  
catch(Exception e){e.printStackTrace ();} OHb[qX\  
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Utility.log(nFileLength); -y8`yHb_  
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return nFileLength; o7s
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} :7!0OVQla\  
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//保存下载信息（文件指针位置） 8&?s#5zA  
private void write_nPos() *KV0%)}sbL  
{ Rn9m]x  
try{ ,!Z
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output = new DataOutputStream(new FileOutputStream(tmpFile)); a1+#3X.  
output.writeInt(nStartPos.length); vdx0i&RiL  
for(int i=0;i<nStartPos.length;i++) {B?Wu3-  
{ WJkZ!O$"j  
// output.writeLong(nPos); V )x$|!(  
output.writeLong(fileSplitterFetch.nStartPos); &eCa0s?mI  
output.writeLong(fileSplitterFetch.nEndPos); :U3kW8;UMP  
} T|7}EAR=b  
output.close(); c#Sa]n  
} C)@y5. G;  
catch(IOException e){e.printStackTrace ();} pb ~uE  
catch(Exception e){e.printStackTrace ();} r? NznNVU  
} mKL<<L[  
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//读取保存的下载信息（文件指针位置） K]s[5  
private void read_nPos() njScz"L~  
{ >L;eO'D  
try{ ^;Y|3)vvB  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); r@+ri1c  
int nCount = input.readInt(); G-xDN59K  
nStartPos = new long[nCount]; ftvG\Tf  
nEndPos = new long[nCount]; VY;{/.Sa  
for(int i=0;i<nStartPos.length;i++) 6y+Kjd/D  
{ 1zm ulj%&  
nStartPos = input.readLong(); XQ9O$ ~q  
nEndPos = input.readLong(); 'IZI:V"  
} rz wF~-m +  
input.close(); u frW\X  
} tyXuG<  
catch(IOException e){e.printStackTrace ();} Kwefs;<E?  
catch(Exception e){e.printStackTrace ();} &]e'KdXF  
} bJRN;g  
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private void processErrorCode(int nErrorCode) !sDh4jQ`  
{ =vQcYa  
System.err.println("Error Code : " + nErrorCode); e+$p9k~  
} 4 N H  
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%QH)'GJQ  
//停止文件下载  `x l   
public void siteStop() <49K>S9O  
{ s}UjGFP  
bStop = true;  87<-kV  
for(int i=0;i<nStartPos.length;i++) +Z7th7W/,  
fileSplitterFetch.splitterStop(); pk?w\A}  
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} u<3HQ.:;  
} OMWbZ>jB  
//负责部分文件的抓取 9N9L}k b  
**FileSplitterFetch.java u [m  
*/ ,uo'c_f(e  
package NetFox; ?EJD?,}  
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import java.io.*; IE;~?W"  
import java.net.*; 9xO#tu]  
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public class FileSplitterFetch extends Thread { |X0Y-  
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String sURL; //File URL 9K5pwC\$%  
long nStartPos; //File Snippet Start Position ),UX4%K=  
long nEndPos; //File Snippet End Position Gb8D[1=u=  
int nThreadID; //Thread's ID ,4zmb`dP<  
boolean bDownOver = false; //Downing is over mQCeo}7N5  
boolean bStop = false; //Stop identical WFO4gB*  
FileAccessI fileAccessI = null; //File Access interface }4Tc  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (g[h 8 c  
{ _A+s)]}  
this.sURL = sURL; MHh~vy'HB5  
this.nStartPos = nStart; Wc,~{  
this.nEndPos = nEnd; w.H%R-Be  
nThreadID = id; X9p.gXF  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9z}uc@#D=m  
} M)eO6oX|  
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public void run() JRSSn]pw  
{ +?u~APjNN  
while(nStartPos < nEndPos && !bStop) q#vQv5  
{ RA KFU  
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try{ ]$Yvj!K
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URL url = new URL(sURL); Fs{x(_LOr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Y
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httpConnection.setRequestProperty("User-Agent","NetFox"); ~aMlr6;  
String sProperty = "bytes="+nStartPos+"-"; A*2 bA  
httpConnection.setRequestProperty("RANGE",sProperty); ^cczJOxB  
Utility.log(sProperty); ^aH\7J@Y  
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InputStream input = httpConnection.getInputStream(); b~'"^ Bts*  
//logResponseHead(httpConnection); PV9pa/`@  
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byte[] b = new byte[1024]; JHz [7  
int nRead; r30 <(nF  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <\NY<QIwFw  
{ B$b +Ymu  
nStartPos += fileAccessI.write(b,0,nRead); i
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//if(nThreadID == 1) '+osf'&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .q9 $\wM/  
} 7w'wjX-  
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Utility.log("Thread " + nThreadID + " is over!"); 3):A   
bDownOver = true; NF+iza;DP  
//nPos = fileAccessI.write (b,0,nRead); y^%
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} n^z]q;IN2.  
catch(Exception e){e.printStackTrace ();} {B[=?6tQ  
} 7(qE0R&@  
} P"W2(d  
&;+-?k|  
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//打印回应的头信息 [-\%4  
public void logResponseHead(HttpURLConnection con) ^:#D0[  
{ h{
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for(int i=1;;i++) OY:
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{ Zn ''_fjh  
String header=con.getHeaderFieldKey(i); 5[A@gw0u  
if(header!=null) ~ vJ,`?  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); W7 Cc  
Utility.log(header+" : "+con.getHeaderField(header)); } \XfH  
else R $&o*K`?  
break; rcMwFE?|xq  
} +n#V[~~8AI  
} $Hj.{;eC/k  
}HY-uQ%@g  
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public void splitterStop() F)W:  
{ _>| =L W@7  
bStop = true; R~)\3] "2m  
} @7?#Y|`  
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} KTP8?Q"n0  
"J4WzA%i  
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/* hnDBFQ{  
**FileAccess.java 13@|w1/Z  
*//文件访问(定位，写) cUA7#1\T=  
package NetFox; 89o/F+_b  
import java.io.*; NdzSz]q}  
;`^WGS(3.%  
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public class FileAccessI implements Serializable{ G&4&-<  
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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 ptU\[Tq  
RandomAccessFile oSavedFile; J[4mLU  
long nPos; i70wrW#k  
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. koYHq  
public FileAccessI() throws IOException \'|>p/5I  
{ i[?Vin  
this("",0); >AcrG]  
} ^-,xE>3o  
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b)=[
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public FileAccessI(String sName,long nPos) throws IOException Kjs.L!W
 
{ `QyO`y=?[Y  
oSavedFile = new RandomAccessFile(sName,"rw"); q U]gj@R  
this.nPos = nPos; SV2M+5#;  
oSavedFile.seek(nPos); OoA|8!CFa  
} "x
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)XYv}U  
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public synchronized int write(byte[] b,int nStart,int nLen) yF"1#{*y  
{ =y0C1LD+  
int n = -1; B2C$N0R#  
try{ JV]^zW  
oSavedFile.write(b,nStart,nLen); OH">b6>\  
n = nLen; ?XA
2&  
} Z yE `/J'  
catch(IOException e) DV<` K$ET  
{ cd$m25CxC  
e.printStackTrace (); XpBj%e:  
} PfC!lI BU  
I?ae\X@M
  
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return n; NiU2@zgl  
} P!+'1KR  
] :BX!<  
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} SVO3821  
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/* 
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**SiteInfoBean.java %l,,_:7{  
*/  B[Zjfc  
package NetFox; V3c l~  
Ahk8  
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public class SiteInfoBean { v"OY 1<8  
u%$Zqee  
1@QZnF5[  
private String sSiteURL; //Site's URL YN!>}  
private String sFilePath; //Saved File's Path ^(|vsFz
n  
private String sFileName; //Saved File's Name 2\7`/,U6  
private int nSplitter; //Count of Splited Downloading File :k.NbN$i\  
PzA|t;*
  
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public SiteInfoBean() >i5acuth  
{//nSplitter的缺省值为5 ]8f ms(  
//default value of nSplitter is 5 +(C6#R<LI  
this("","","",5); Cb9;QzBVA#  
} vfq%H(  
HA2k[F@3^  
{a4z2"\A  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) )0Me?BRp  
{ \ aHVs  
sSiteURL= sURL; U2ZD]q  
sFilePath = sPath; \9/ b
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sFileName = sName; Lz:(6`S  
this.nSplitter = nSpiltter; { Fawt:  
,)iKH]lY=  
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} .h>8@5/s  
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public String getSSiteURL() jz5qQt]^  
{ sIK;x]Q)  
return sSiteURL; TJ1+g \  
} M $Es%  
.8P.)%  
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public void setSSiteURL(String value) "87ghj_}  
{ 2U; t(,dn'  
sSiteURL = value; m<0&~rg   
} WV#%PJ  
v7DE  
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public String getSFilePath() {6~l$  
{ []A%<EI7  
return sFilePath; 4Rvf  
} #@"<:!?z  
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public void setSFilePath(String value) hrhb!0  
{ Xt#4/>dlR  
sFilePath = value; qt;y2gf=  
}
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#_(jS+lP?k  
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public String getSFileName() #:^YI c  
{ -$WYj"  
return sFileName; L30$%G|  
} e}.^Tiwd]  
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5<ux6,E1{  
public void setSFileName(String value) j'BMAn ?  
{ ##EYH1P]  
sFileName = value; hYM@?/(q  
} Xa[?^P  
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public int getNSplitter() tX"Th'Qi  
{ ,I_^IitN  
return nSplitter; &b
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} e`v`XSA[p  
@$2))g`  
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public void setNSplitter(int nCount) q7-L53.x  
{ ~I799Xi  
nSplitter = nCount; Ce")[<:  
} 6'RrQc=q  
} gF5a5T,  
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/* ty*@7
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**Utility.java }-o{ASC#  
*/ y
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package NetFox; ;x8k[p~2  
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&2=dNREJ}1  
public class Utility { K.z64/H:  
]Wq?H-B{  
\;mH(-  
public Utility()
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{ Kbb78S30  
!\,kZ|#>  
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} %bD}m!  
4|`Bq}sjZf  
//线程睡眠 P7x =  
public static void sleep(int nSecond) H_ez'yy  
{ ,+ #6Y_  
try{ }A:<%N  
Thread.sleep(nSecond); \C`~S7jC  
} ?&^?-S% p  
catch(Exception e) ryc& n5  
{ _"#!e{N|  
e.printStackTrace (); n]u<!.X  
} \#>T~.Y7K  
} /g$G_}  
-#Z bR  
//日志 `St.+6^J  
public static void log(String sMsg) fS"Hr0  
{ W5'3$,X9  
System.err.println(sMsg); .]9c/  
} T1r3=Y4  
jh.@-  
kee|42E  
public static void log(int sMsg) f7'q-  
{ a+9*@z2  
System.err.println(sMsg); AT\qiznvP  
} xGG,2W+z  
} _` [h,=  
}h}<!s  
&V<W>Y>|l*  
/* 7oR:1DXw|  
**TestMethod.java ) 9oH,gZ  
*/ )#}mH@  
package NetFox; KPpHwcYxT  
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$L2%u8}8:  
public class TestMethod { nxJee=qH  
o8Z[+;  
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public TestMethod() wHem5E  
{ ///xx/weblogic60b2_win.exe ;kJu$U  
try{ 2Gs$?}"a  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); hG_?8:W8HT  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,= &B28Qe)  
SiteFileFetch fileFetch = new SiteFileFetch(bean); IB`>'~s&A  
fileFetch.start(); "aFhkPdWn  
} LsM7hLy  
catch(Exception e){e.printStackTrace ();} F>X-w+b4r  
N7s'6(`=X  
7HHysNB"w  
} lMz<s  
:SsUdIX;P  
7E@+  
public static void main(String[] args) 4A3nO<oMF  
{ i#%a-I:
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new TestMethod(); wfjc/u9W6R  
} }BmS)Jq  
} q,2]5'  
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