http断点续传简单实现（java)

/* MnTJFo"  
**SiteFileFetch.java
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*/ H;{IOBo  
package NetFox; IN7Cpg~9%  
import java.io.*; P"f4`q  
import java.net.*; ,{2= nb[  
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 !U=o<)I  
public class SiteFileFetch extends Thread { l/-qVAd!q  
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SiteInfoBean siteInfoBean = null; //文件信息Bean pS+hE4D  
long[] nStartPos; //开始位置 [P*zm8b  
long[] nEndPos; //结束位置 &oxHVZJ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~$d(@T&  
long nFileLength; //文件长度 D6,Ol4d  
boolean bFirst = true; //是否第一次取文件 k
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boolean bStop = false; //停止标志 3/V0w|Z
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File tmpFile; //文件下载的临时信息 # 11<=3Yj  
DataOutputStream output; //输出到文件的输出流 *I.eCMDa  
[\-)c[/  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） `*",_RO;  
public SiteFileFetch(SiteInfoBean bean) throws IOException >u+%H vzc  
{ |eI!wgQx  
siteInfoBean = bean; wC?>,LOl  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); uj:1_&g  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -% \LW1  
if(tmpFile.exists ()) 0K4A0s_R`  
{ TeRH@oI  
bFirst = false; 4Z.Dz@.c(  
read_nPos(); aGNbCm  
} *$Y_ %}  
else #'dNSez5  
{ ]Z?jo#F  
nStartPos = new long[bean.getNSplitter()]; .z[#j]k  
nEndPos = new long[bean.getNSplitter()]; S!66t?vHB  
}
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} L~Y^O`c  
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public void run() Je4hQJ<h  
{ o.(Gja4  
//获得文件长度 ;)FmN[  
//分割文件 tyFsnck  
//实例FileSplitterFetch 4%#q.qI  
//启动FileSplitterFetch线程 c#-*]6x  
//等待子线程返回 &H[7UyC  
try{ QXW>}GdKZ  
if(bFirst) qOv`&%txW  
{ >XxHp  
nFileLength = getFileSize(); @r=,: 'Mt  
if(nFileLength == -1) '<$*N  
{ :7~DiH:
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System.err.println("File Length is not known!"); 1zgM
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} ;3XOk+  
else if(nFileLength == -2) 6)c-s|#  
{ {YG qa$+\  
System.err.println("File is not access!"); 
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} wLzV#8>  
else "U/yq
 
{ Nw{Cu+AwG  
for(int i=0;i<nStartPos.length;i++) iJ`zWpj+{Q  
{ />wE[`  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); gC(@]%  
} L;WFHIE  
for(int i=0;i<nEndPos.length-1;i++) 0BH-kr  
{ (/FG#D.  
nEndPos = nStartPos[i+1]; ZW4$Ks2]Y  
} h>F"GR?U_(  
nEndPos[nEndPos.length-1] = nFileLength; q4v:s   
} 5O;D\M{>  
} ;iW>i8  
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j2%fAs<  
//启动子线程 a"`>J!  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; WL?qulC}h1  
for(int i=0;i<nStartPos.length;i++) }0?XF/e(R  
{ Shv$"x:W  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), OZA^L;#>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), W
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nStartPos,nEndPos,i); qeb}~FL"o  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C-\3,  
fileSplitterFetch.start(); xIwILY|W=  
} O`5hjq#  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \AIFIy  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);  /PTq.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", [N#4H3GM8  
nEndPos = " + nFileLength); Km,%p@`m  
// fileSplitterFetch[nPos.length-1].start(); q0DRT4K  
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//等待子线程结束 |*DkriYY  
//int count = 0; -{q'Tmst  
//是否结束while循环 upZtVdd  
boolean breakWhile = false; FmhAUe  
v!$:t<-5N  
mT #A?C2  
while(!bStop) E]}_hZU  
{ t1G__5wp  
write_nPos(); M|Nh(kvH  
Utility.sleep(500); nSRNd A  
breakWhile = true; |o+*Iy)  
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2j#Dwa(lZQ  
for(int i=0;i<nStartPos.length;i++) U#&+n-npO  
{ o/Q|R+yXV  
if(!fileSplitterFetch.bDownOver) " %qr*
|  
{ $E.Fgy:G  
breakWhile = false; D)Ep!`Q   
break; )U7fPKQ  
} 1wm`a  
} ^!x! F  
if(breakWhile) 81C;D`!K  
break; M6bM`wHH>  
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//count++; Ql%B=vgKL  
//if(count>4) UNK.39  
// siteStop(); Nukyvse  
} V]GF
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! ,{zDMA  
System.err.println("文件下载结束！"); S^;;\0#NK  
} ~$C}?y^ a  
catch(Exception e){e.printStackTrace ();} !Z 0U_*&  
} kDXQpe  
,iY:#E  
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//获得文件长度 pwkTe  
public long getFileSize() \<\H1;=.@'  
{ &]GR
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int nFileLength = -1; *X{7m]5  
try{ IsShAi  
URL url = new URL(siteInfoBean.getSSiteURL()); 8};kNW^2m  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); KVr9kcs  
httpConnection.setRequestProperty("User-Agent","NetFox"); GzBPI'C  
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int responseCode=httpConnection.getResponseCode(); /.=aA~|  
if(responseCode>=400) CBF<53TshR  
{ lSlZ^.&  
processErrorCode(responseCode); QnP?j&  
return -2; //-2 represent access is error G+Bk!o  
} znSlSQpTv  
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String sHeader; 0kNKt(_  
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for(int i=1;;i++) d7m

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{ }2;iIw`  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); <:NahxIlu  
//Utility.log(in.readLine()); B
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sHeader=httpConnection.getHeaderFieldKey(i); vm{8x o  
if(sHeader!=null) +2}cR66%  
{ [ZC\8tP`V  
if(sHeader.equals("Content-Length")) 93:oXyFjD  
{ 9#m3<oSJ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); #/jug[wf*!  
break; Xdo\DQn  
}
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} Kh[l};/F  
else F\^8k/0  
break; SDV#p];u  
} LMx/0  
} $v[mIR  
catch(IOException e){e.printStackTrace ();} 3;VH'hh_  
catch(Exception e){e.printStackTrace ();} %p$XK(6  
vd(S&&]o1  
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Utility.log(nFileLength); dP(.l}O  
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return nFileLength; C:}1r  
} HA,8O[jon  
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:  
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//保存下载信息（文件指针位置） eY
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private void write_nPos() KvEv0L<ky  
{ 7s3=Fa:9Q  
try{ iw=e"6V  
output = new DataOutputStream(new FileOutputStream(tmpFile)); sNcU>qjj6  
output.writeInt(nStartPos.length); @eeI4Jz  
for(int i=0;i<nStartPos.length;i++) U,Uy0s2r  
{ od5nRb  
// output.writeLong(nPos); m;\nMdn  
output.writeLong(fileSplitterFetch.nStartPos); jf`w8*R  
output.writeLong(fileSplitterFetch.nEndPos); =}kISh  
} mXyN{`q=  
output.close(); 4w=v /WDo  
} fM7B<eB  
catch(IOException e){e.printStackTrace ();} s
ve} ent  
catch(Exception e){e.printStackTrace ();} h@\-]zN{  
} {:*G/*1[.  
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//读取保存的下载信息（文件指针位置） 88,hza`#V  
private void read_nPos() 7)5G 1  
{ _h5d~  
try{ w8R7Ksn(  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); gd]S;<Jh  
int nCount = input.readInt(); HcJ!(
 
nStartPos = new long[nCount]; o$l8"Uv  
nEndPos = new long[nCount]; pfHjs3A=  
for(int i=0;i<nStartPos.length;i++) egSs=\  
{ L.yM"  
nStartPos = input.readLong(); UPr& `kaJ  
nEndPos = input.readLong(); d~rA`!s7`  
} &9)/"  
input.close(); v%AepK&  
} 5,s@K>9l;  
catch(IOException e){e.printStackTrace ();} F-rhxJd  
catch(Exception e){e.printStackTrace ();} "yh2+97l  
} /g!
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private void processErrorCode(int nErrorCode) .\T!oSb4[  
{ W_E^+Wl@  
System.err.println("Error Code : " + nErrorCode); l0`bseN<  
} 0m]QQGvJ{  
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B  
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//停止文件下载 h&CZN !  
public void siteStop() 2ua!<^,  
{ 7yT/t1)  
bStop = true; fh3uo\`@  
for(int i=0;i<nStartPos.length;i++) XPqGv=CN  
fileSplitterFetch.splitterStop(); L(K 5f7\  
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} nRB3VsL  
} ;22?-F^  
//负责部分文件的抓取 3IQI={:k|D  
**FileSplitterFetch.java }xt^}:D  
*/ ?!U.o1  
package NetFox; s|A[HQUtJ  
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}A@:JR+|  
import java.io.*; *cCx]C.~  
import java.net.*; j3;W-c`5  
i0/QfB%O  
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public class FileSplitterFetch extends Thread { zJW2F_  
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String sURL; //File URL ;lb  
long nStartPos; //File Snippet Start Position PNo:[9`S;m  
long nEndPos; //File Snippet End Position ]?H12xz  
int nThreadID; //Thread's ID 0C%IdV%CU  
boolean bDownOver = false; //Downing is over lSaX!${R'T  
boolean bStop = false; //Stop identical RHn3\N  
FileAccessI fileAccessI = null; //File Access interface *(1<J2j  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException XZ]ji9'  
{ [pEb`s  
this.sURL = sURL; ()Kaxcs?+  
this.nStartPos = nStart; `r-Jy{!y4  
this.nEndPos = nEnd; vJGH8$%;,  
nThreadID = id; /huh}&NNu  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 FCEmg0qdjD  
} CF','gPnc  
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public void run() aY?VP?BL  
{ D
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while(nStartPos < nEndPos && !bStop) ?M&@# lbG  
{ >Rt:8uurAG  
\9OKf|#j  
\RR` F .7  
try{ BWxJ1ENM  
URL url = new URL(sURL); "1^tVw|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); f!yl&ulKU  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5j.@)XXe  
String sProperty = "bytes="+nStartPos+"-"; WHBGhU  
httpConnection.setRequestProperty("RANGE",sProperty); X9|*`h<  
Utility.log(sProperty); X)hpbHa  
O&aD]~|
  
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InputStream input = httpConnection.getInputStream(); 4[x`\  
//logResponseHead(httpConnection); \ [OB.  
8%u|[Si;  

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byte[] b = new byte[1024]; ysK J=  
int nRead; DFQ`(1Q  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <";1[A%7<  
{ YYFS ({  
nStartPos += fileAccessI.write(b,0,nRead); \^9n&MonM  
//if(nThreadID == 1) ]zyT_}&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); AN:s%w2  
} "IQYy~ /  
>SvS(N{  
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Utility.log("Thread " + nThreadID + " is over!"); O>hh  
bDownOver = true; 0lniu=xmQ-  
//nPos = fileAccessI.write (b,0,nRead); 8g)$%Fy+N  
} C}<e3BXc  
catch(Exception e){e.printStackTrace ();} D=z="p\  
} ]!sCWR  
} $mKExW  
]!^wB 3j  
"@^<~bw  
//打印回应的头信息 -QJ8\/1>  
public void logResponseHead(HttpURLConnection con) NY<qoV  
{ ktynI
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for(int i=1;;i++) ca3zY|Oo  
{ BaI-ve  
String header=con.getHeaderFieldKey(i); 3GKKC9C6  
if(header!=null) k3t]lGp  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ih.)iTs~%  
Utility.log(header+" : "+con.getHeaderField(header)); bcwb'D\a  
else :TP4f ?FA  
break; +{=U!}3|  
} A9@coP5  
} zL}`7*d:v  
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*2-b&PQR{  
public void splitterStop() {
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{ _u6NaB  
bStop = true; Q%q;=a  
} hG~.Sc:G  
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} ltkARc3  
;Dp*.YJ  
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/* <5j%!6zo  
**FileAccess.java }jC^&%|  
*//文件访问(定位，写) E A55!  
package NetFox; 0[d*Z  
import java.io.*; X=f%!
  
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{  
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public class FileAccessI implements Serializable{ 9pj6`5Zn@6  
u@:[ dbJ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 K@2"n| S;  
RandomAccessFile oSavedFile; Z-4/xi7  
long nPos; zmD7]?|  
t+F_/_"B  
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public FileAccessI() throws IOException seAPVzWUU  
{ NQuqM`LSQ  
this("",0); `_1fa7,z  
} x%H,ta%  
|BhL.  
p>J@"?%^  
public FileAccessI(String sName,long nPos) throws IOException 9S9j  
{ YW~ 9N  
oSavedFile = new RandomAccessFile(sName,"rw"); N<4 nb  
this.nPos = nPos; Dpu?JF]  
oSavedFile.seek(nPos); 1'p=
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} *'H\`@L  
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public synchronized int write(byte[] b,int nStart,int nLen) #b)
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{ |N6.:K[`  
int n = -1; K% snE7X?)  
try{ \Ezcr=0z{j  
oSavedFile.write(b,nStart,nLen); 3rHn?  
n = nLen;
' e!WZvr  
} M6A0D+08  
catch(IOException e) BUsxgs"),  
{ iyR"O1]  
e.printStackTrace (); 9dAtQwGR"6  
} `S-%}eUv  
{"$[MYi:  
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return n; M,kO7g  
} $.w$x1  
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} ojm IEzsz  
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/* 0:I<TJ~P  
**SiteInfoBean.java
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*/ \I}EWI  
package NetFox; ^ZS!1%1  
@x!
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public class SiteInfoBean { k$f2i,7'  
(dyY@={q  
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private String sSiteURL; //Site's URL OXKV6r6f  
private String sFilePath; //Saved File's Path d)Z&_v<|  
private String sFileName; //Saved File's Name o+XQMg  
private int nSplitter; //Count of Splited Downloading File +rSU  
OR $i,N|  
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public SiteInfoBean() z>y#^f)r  
{//nSplitter的缺省值为5 #l- 0$  
//default value of nSplitter is 5 0J466H_d{  
this("","","",5); S#yGqN0i  
} a%kvC#B  
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/uR/,R++  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 1\aTA,  
{ [S~Bt78d%r  
sSiteURL= sURL; 1/;E8{  
sFilePath = sPath; ;34p [RT  
sFileName = sName; ;P;c!}:\b  
this.nSplitter = nSpiltter; :qB|~"9O  
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?GhMGpdMq  
} ?D)$OCS  
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public String getSSiteURL() O8" t.W  
{ o%;ly  
return sSiteURL; ~a_X 7
 
} n=$ne2/  
.<fdX()e,  
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public void setSSiteURL(String value) yVGf[~X  
{ <Ist^h+o  
sSiteURL = value; a8Xwz@ M  
} 1(>2tEjYT  
;;Z'd@  
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public String getSFilePath() HYT~AO-!  
{ $- %um  
return sFilePath; EN/t5d  
} dy5}Jn%L  
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public void setSFilePath(String value) m`q&[:  
{ ewdTsgt'  
sFilePath = value; m0h,!  
} 52#6uBe  
m2l9([u=^  
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public String getSFileName() &hL2xx=  
{ 4J
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return sFileName; Q/4ICgo4  
} &)||~  
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7 wEv`5  
public void setSFileName(String value) puWMgvv  
{ 6~W@$SP,F  
sFileName = value;
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} ybFxz  
, u%V%  
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public int getNSplitter() >!']w{G  
{ z^&$6c_  
return nSplitter; Tl[*(|/C  
} f#GMJ mCQs  
|%F4`gz8KP  
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public void setNSplitter(int nCount) C^B$_?  
{ +0Q 
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nSplitter = nCount; vbtZ5Gm   
} oCI\yp@a  
} ,5}w]6bCr  
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#Cu$y8~as  
/* q%$p56\?3  
**Utility.java #Y'b?&b  
*/ hqjjd-S0  
package NetFox; )b2O!p  
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public class Utility { +5Dc5Bl  
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public Utility() 5*YvgB;  
{ em0Y'J  
\**j\m   
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} A]i!131{w|  
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//线程睡眠 #\D74$D  
public static void sleep(int nSecond) [Eu)~J*
 
{ p0zC(v0*  
try{ LK
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Thread.sleep(nSecond); vo*oCfm  
} 6XU p$Pd(  
catch(Exception e) BU??}{  
{ s>L
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e.printStackTrace (); 7t
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} h| wdx(4  
} eh]syeKBj  
.lP',hn  
//日志 VWHpfm[r%  
public static void log(String sMsg) UdnRsp9S  
{ q jc4IW t~  
System.err.println(sMsg); Cfd* Q  
} ~AX~z)  
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public static void log(int sMsg) ?H@<8Ra=3  
{ s9nPxC&A  
System.err.println(sMsg); p!uB8F  
} {R@V  
} Lkx~>U   
)qbkKCq/FB  
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/* (Ll'j0]k>  
**TestMethod.java  @,k5T51m  
*/ U1)Zh-aR  
package NetFox; (y.
N-I,  
+BL46Bq  
X"_ ^^d-  
public class TestMethod { sHk>ek]2I  
  P3|s}&  
0!lWxS0#=  
public TestMethod() !Pnjr T  
{ ///xx/weblogic60b2_win.exe ! {G0'  
try{ l}VE8-XB  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^4"AWps  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Q]N&^ E  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =|I
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fileFetch.start(); [{u3g4`}  
} v7./u4S|V  
catch(Exception e){e.printStackTrace ();} v]F4o1ckk  
t4v'X}7q]  
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} v=lW5%r,'  
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!f5
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public static void main(String[] args) 2 Kjd!~Z$  
{ ;2&"
 
new TestMethod(); breF,d$  
} LAf#Rco4  
} O=}Rp1  
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