http断点续传简单实现（java)

/* w@2LFDp  
**SiteFileFetch.java 5*>3(U  
*/ `24:Eg6r  
package NetFox; }c,}+{q
 
import java.io.*; 'lNl><
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import java.net.*; -/
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public class SiteFileFetch extends Thread {
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SiteInfoBean siteInfoBean = null; //文件信息Bean ,K6]Q|U@r  
long[] nStartPos; //开始位置 5cQBqH]   
long[] nEndPos; //结束位置 i]LK,'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \9k{"4jX\  
long nFileLength; //文件长度 Xl*-A|:j  
boolean bFirst = true; //是否第一次取文件 ig/716r|  
boolean bStop = false; //停止标志
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File tmpFile; //文件下载的临时信息 |@-WC.  
DataOutputStream output; //输出到文件的输出流 6YU2  !x  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） c\4n7m,y  
public SiteFileFetch(SiteInfoBean bean) throws IOException iVu+ct-iv  
{ z?"5="D  
siteInfoBean = bean; JT^E`<nn  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); c)E[K-u  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); I}v'n{5(  
if(tmpFile.exists ()) )3B5"b,  
{ n7q-)Dv_U  
bFirst = false; ?3z+|;t6C  
read_nPos(); 3]Lk}0atpL  
} TzL40="F  
else W@$p'IBwm  
{ (\/HGxv  
nStartPos = new long[bean.getNSplitter()]; O\KAvoQ%s  
nEndPos = new long[bean.getNSplitter()]; c)6Y.[
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} q%:Jmi>  
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} sqZHk+<%  
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public void run() MthThsr7  
{ 47K5[R  
//获得文件长度 4l`gAE$  
//分割文件 \]ODpi 2  
//实例FileSplitterFetch o"1us75P  
//启动FileSplitterFetch线程 D
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//等待子线程返回 MM8)yCI  
try{ };!c]/,  
if(bFirst) B=c^ma
  
{ NJtB;  
nFileLength = getFileSize(); eu:_V+  
if(nFileLength == -1) N~ozyIP,  
{ -5ec8m8  
System.err.println("File Length is not known!"); Y) t}%62  
} .CpF
0  
else if(nFileLength == -2) YYvs~?bAy  
{ 6Rf5  
System.err.println("File is not access!"); oV!9B-<  
} 5~"=Fm<uD  
else  zm.2L  
{ 86I*
 
for(int i=0;i<nStartPos.length;i++) Hf-F-~E  
{ (_08?cN  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `WW0~
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} }I`|*6Up  
for(int i=0;i<nEndPos.length-1;i++) 8say"Qz  
{ Q8~
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nEndPos = nStartPos[i+1]; q%vUEQLBp  
} N+V-V-PVk  
nEndPos[nEndPos.length-1] = nFileLength; &L?Dogo  
} ,RHHNTB("  
} A{o{o++  
v:0i5h&M  
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//启动子线程 XN0Y#l  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; U+i[r&{gb  
for(int i=0;i<nStartPos.length;i++) rh l5r"%  
{ %%>?<4t  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ZF/KV\Ag)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), .eAC!R  
nStartPos,nEndPos,i); I(CI')Q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,i,=LGn  
fileSplitterFetch.start(); nJya1AH;  
} Z7/dRc   
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {LeEnh-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);  k WtUj  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", >dl!Ep  
nEndPos = " + nFileLength); N9ufTlq s  
// fileSplitterFetch[nPos.length-1].start(); ybG)=0  
i=a LC*@  
@6!JW(,]\  
//等待子线程结束 `+o.w#cl  
//int count = 0; =KZ4:d5  
//是否结束while循环 Vel;t<1  
boolean breakWhile = false; u@EM,o  
{EUH#':  
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while(!bStop) M5V1j(URE  
{ g3XAs@  
write_nPos(); A!kyga6F5  
Utility.sleep(500); D+3Y.r9  
breakWhile = true; aVYUk7_<  
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for(int i=0;i<nStartPos.length;i++) {\&"I|dpe  
{ f)x}_dw%  
if(!fileSplitterFetch.bDownOver) zOOX>3^  
{ iFA"m;$  
breakWhile = false; *La =7y:  
break; S8RB0^Q7  
} &3f.78a  
} jQ)>XOok  
if(breakWhile) 5!zvoX9  
break; \G@6jn1G(  
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//count++; `RcNqPY#S  
//if(count>4) sriz b  
// siteStop(); JY
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} srLr~^$j[  
&^_(xgJL  
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System.err.println("文件下载结束！"); eeZysCy+DY  
} V2,WP  
catch(Exception e){e.printStackTrace ();} n y)P  
} YMTA`T(+  
^^SfIK?p  
7nz
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//获得文件长度 syf"{bBe  
public long getFileSize() 61/zrMPn  
{ 8!GLw-kb  
int nFileLength = -1; H|U/t
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try{ ..!-)q'?  
URL url = new URL(siteInfoBean.getSSiteURL()); I uj=d~|>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /AW>5r]  
httpConnection.setRequestProperty("User-Agent","NetFox"); B7MW" y  
] <3?=$  
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int responseCode=httpConnection.getResponseCode(); %UQB?dkf$  
if(responseCode>=400) 'kvFU_
)  
{ N-9gfG  
processErrorCode(responseCode); ^&H=dYcV>/  
return -2; //-2 represent access is error A'1AU:d  
} R?~h7 d  
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String sHeader; jYX9;C;J  
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for(int i=1;;i++) \{zAX~k6  
{ bV*zMoD#  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A9Wqz"[  
//Utility.log(in.readLine()); vfUfrk@D~  
sHeader=httpConnection.getHeaderFieldKey(i); Gc!8v}[7J  
if(sHeader!=null) s;7qNwYO  
{ :V~*vLvR  
if(sHeader.equals("Content-Length")) c dbSv=r  
{ dMmka
  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); -QPWi2:k  
break; u7&'3ef  
} 5MY}(w  
} ;nKHm  
else B8AzN9v&"N  
break; SM+fG:4d  
} kdh9ftm*\  
} Df~p'N-$  
catch(IOException e){e.printStackTrace ();} (Q8?)  
catch(Exception e){e.printStackTrace ();} |p -R9A*>h  
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Utility.log(nFileLength); a
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return nFileLength; hdtnC29$  
} \41)0,sEy  
1D
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//保存下载信息（文件指针位置） C%
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private void write_nPos() (}1v^~FXj  
{ `m3QT3B  
try{ +^DRto=  
output = new DataOutputStream(new FileOutputStream(tmpFile)); +1Rrkok  
output.writeInt(nStartPos.length); eSX[J6  
for(int i=0;i<nStartPos.length;i++) !x$:8R  
{ JkDPuTXD  
// output.writeLong(nPos); #;LMtDaL  
output.writeLong(fileSplitterFetch.nStartPos); L\m!8o4  
output.writeLong(fileSplitterFetch.nEndPos); <cv2-?L{  
} 'gZbNg=&[  
output.close(); H<Kkj  
} #} ~p^ 0  
catch(IOException e){e.printStackTrace ();} ).}k6v[4)  
catch(Exception e){e.printStackTrace ();} ,0uo&/Y4L  
} [AX"ne#M*  
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//读取保存的下载信息（文件指针位置） I\rZk9F  
private void read_nPos() xR|eyeR  
{ D<bU~Gd,P  
try{ vDW&pF_eI>  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;eW'}&|LV  
int nCount = input.readInt(); H*{k4  
nStartPos = new long[nCount]; K@jSr*\'  
nEndPos = new long[nCount]; G?1x+H;o5  
for(int i=0;i<nStartPos.length;i++) ;4kx
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{ ,V33v<|wc  
nStartPos = input.readLong(); IQw %|
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nEndPos = input.readLong(); r'd:SaU+  
} $35,\ZO>  
input.close(); }*.:Hv"  
} 1]>$5 1Q  
catch(IOException e){e.printStackTrace ();} nGx ~)T  
catch(Exception e){e.printStackTrace ();} chO'Q+pw  
} gj[ >p=Wn  
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private void processErrorCode(int nErrorCode) G}P)vfcH  
{ ,TF<y#wed  
System.err.println("Error Code : " + nErrorCode); 7sud/*+F  
} 9V=<| 2  
p;qRm} 0}  
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//停止文件下载 ^V<J69ny|9  
public void siteStop() yX7CN5vVl  
{ e{fZ}`=7y  
bStop = true; W>Mse[6`c  
for(int i=0;i<nStartPos.length;i++) \;-=ODC  
fileSplitterFetch.splitterStop(); J4gI=@e  
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} t
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} OgEUq''  
//负责部分文件的抓取 S9G8aea/  
**FileSplitterFetch.java v#<\:|XAg  
*/ 2q"_^deI5*  
package NetFox; =MTj4VXh"  
<#xrrRhm}  
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import java.io.*; ]`zjRRd  
import java.net.*; b A)b`1lI  
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public class FileSplitterFetch extends Thread { |`w$|pm=  
09R,'QJ|  
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String sURL; //File URL fd?bU|I_2  
long nStartPos; //File Snippet Start Position h'B9|Cm  
long nEndPos; //File Snippet End Position _Fy4DVCg  
int nThreadID; //Thread's ID #04{(G|~+E  
boolean bDownOver = false; //Downing is over ,'FD}yw4v  
boolean bStop = false; //Stop identical $Q8P@L)[  
FileAccessI fileAccessI = null; //File Access interface _qY`KP"  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException lq1[r~  
{ tgO+*q5B  
this.sURL = sURL; PSW#^o  
this.nStartPos = nStart; R'G'&H{N  
this.nEndPos = nEnd; xik`W!1S  
nThreadID = id; <9@&oN+T  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "0|BoG  
} m9#}X_&x  
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public void run() ?N4A9W9  
{ ]ddHA  
while(nStartPos < nEndPos && !bStop)  LsQs:O  
{
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try{ mYjf5  
URL url = new URL(sURL); 5\VxXiy0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %z1{Kus  
httpConnection.setRequestProperty("User-Agent","NetFox"); z8b _ _%Br  
String sProperty = "bytes="+nStartPos+"-"; +``>,O6  
httpConnection.setRequestProperty("RANGE",sProperty); d2ohW|  
Utility.log(sProperty); &c20x+  
"\`>2  
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InputStream input = httpConnection.getInputStream(); j,}4TDWa  
//logResponseHead(httpConnection); [FB&4>V/  
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byte[] b = new byte[1024]; q1UBKhpnH  
int nRead; --Oprl  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) c+1vqbqHG  
{ LlU'
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nStartPos += fileAccessI.write(b,0,nRead); '#H&:Htm;L  
//if(nThreadID == 1) {b
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?LM:RADCm  
} h>dxBN  
?4:rP@  
+q7qK*  
Utility.log("Thread " + nThreadID + " is over!"); b 1cd&e  
bDownOver = true; V{KjRSVf=  
//nPos = fileAccessI.write (b,0,nRead); O8gfiQqF&  
} 1x{XE*%;  
catch(Exception e){e.printStackTrace ();} Mz93  
} _O$tuC%  
} -z
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.Nc_n5D
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//打印回应的头信息 PDhWFF  
public void logResponseHead(HttpURLConnection con) r9?o$=T  
{ n-d:O\]  
for(int i=1;;i++) NNgK:YibD  
{ }bp.OV-+  
String header=con.getHeaderFieldKey(i); NP "ylMr7P  
if(header!=null) 6?O}Q7G  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); L4~ W/6A  
Utility.log(header+" : "+con.getHeaderField(header)); M]1;  
else GN0duV  
break; N.jA 8X  
} rrAqI$6  
} +B#qu/By  
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public void splitterStop() +1x)z~q=  
{ zFOL(s.h|0  
bStop = true; !Pw$48cg  
} 1ADv?+j)A/  
^L ]B5,}-  
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} wajZqC2yg  
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/* o,J^ e_  
**FileAccess.java s*f1x N<  
*//文件访问(定位，写) qT$)Rb&  
package NetFox; Y5n>r@)m  
import java.io.*; c88_}%h?(  
zLL)VFCJW  
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public class FileAccessI implements Serializable{
 b)Tl*  
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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 B_cgWJ*4  
RandomAccessFile oSavedFile; :Z[(A"dA  
long nPos; 6i| ~7md,  
!j{CuA/  
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public FileAccessI() throws IOException :b5XKv^  
{ W]zw
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this("",0); .ots?Ns  
} w [L&*
 
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public FileAccessI(String sName,long nPos) throws IOException {a. <`  
{ ,aWCiu}  
oSavedFile = new RandomAccessFile(sName,"rw"); T~h.=5  
this.nPos = nPos; t?HF-zQ  
oSavedFile.seek(nPos); #v+;:  
} FJ}gUs{m  
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public synchronized int write(byte[] b,int nStart,int nLen) <W2ZoqaV  
{ xdqK.Z%  
int n = -1; 7C?E z%a@  
try{ QAi1,+y]7w  
oSavedFile.write(b,nStart,nLen); u3ST;  
n = nLen; L@?e:*h  
} 12-EDg/1  
catch(IOException e) }Bi@?Sb  
{ >C*4_J7  
e.printStackTrace (); nSHNis  
} \W
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return n; -zdmr"CA  
} PV(4$I}  
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hVkO%]?  
} oBC]UL;8xJ  
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a
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/* i&*<lff  
**SiteInfoBean.java 50*@.!^*  
*/ cf\&No?-p  
package NetFox; G1/Gq.<  
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- zQ<ZE  
public class SiteInfoBean { ~2(]ZfO?>H  
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private String sSiteURL; //Site's URL LZa% x  
private String sFilePath; //Saved File's Path ~?d>fR:X  
private String sFileName; //Saved File's Name E<k^S{  
private int nSplitter; //Count of Splited Downloading File {!r#f(?uT  
R(`]n!V2  
)(]Envb?A0  
public SiteInfoBean() ntZ~m  
{//nSplitter的缺省值为5 x9D/s`!  
//default value of nSplitter is 5 DN<M?u]  
this("","","",5); _JA:.V^3gm  
} j_V/GnEQ  
ol
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{mf.!Xev
 
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) TRy^hr8~  
{ gH'3 dS!{  
sSiteURL= sURL; c 6q/X*  
sFilePath = sPath; wPgDy  
sFileName = sName; UKj`_a6  
this.nSplitter = nSpiltter; V:>`*tlh  
B:nK)"{  
87}(AO)  
} ST% T =_q  
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^)<w*iqBD  
public String getSSiteURL() t}~UYG(h~  
{ {=iyK/Uf  
return sSiteURL; x_W3sS]ej  
} N<n8'XDdG  
~bGC/I;W>  
%6HX*_Mr&  
public void setSSiteURL(String value) mLaCkn
  
{ 61>f(?s  
sSiteURL = value; TzY*;  
} KSsWjF}d  
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public String getSFilePath() 
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{ bRsc-Fz6  
return sFilePath; ;W~4
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} ~ k<SbFp  
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public void setSFilePath(String value) Z/h|\SyJ  
{ ONfyYM?  
sFilePath = value; (!-;T  
} Km"&mT $  
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hIo0S8MOj$  
public String getSFileName() v#F-<?Vv  
{ 3a^)u-9,x  
return sFileName; mw
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} +4HlRGH  
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;j!UY.i  
public void setSFileName(String value) ^vW$XRnt  
{ XmlIj8%9[&  
sFileName = value; #fj[kq)&S  
} C=yD3mVz  
uQ^hV%|"  
6
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public int getNSplitter() 2`E!|X  
{ .:[`j3s)Y  
return nSplitter; b}}y=zO|$  
} v8  
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public void setNSplitter(int nCount) 6%UY1Q.?  
{ \j:AR4  
nSplitter = nCount; sJv`fjf%8  
} 0$QIfT)  
} 0O[l?e4,8{  
)$h-ZYc  
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/* ^}@`!ON  
**Utility.java U3+A MVnB  
*/ OW#_ty_ul  
package NetFox; b|6!EGh  
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public class Utility { #4N >d~  
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public Utility() )vQNiik#  
{ aP_3C_  
&#-[Y:?lA  
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} =E1tgrW  
{KsVK4\r  
//线程睡眠 oSmjs  
public static void sleep(int nSecond) <"A#Eok|4  
{ wx./"m.M  
try{ #w;;D7{@m  
Thread.sleep(nSecond); Vf$1Sjw  
} "vsjen.K>  
catch(Exception e) H) cQO?B  
{ 80HEAv,O  
e.printStackTrace (); \6i9q=  
} jceHKl  
} L\YZT| K(  
]1tN|ODY*W  
//日志 PF`:1;PU  
public static void log(String sMsg) m|mG;8}pI  
{ hwp/jO:7\  
System.err.println(sMsg);  tI'e ctn  
} \QiqcD9Y  
_Qg{ ;  
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public static void log(int sMsg) Txu>/1N,  
{ `BpCRKTG  
System.err.println(sMsg); RW)k_#%=  
} &*jixqzvn
 
} HwM/}-t  
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/* -CwWs~!  
**TestMethod.java h~:H?pj3g  
*/ [&Lxz~W][  
package NetFox; "~Us#4>  
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7F~xq#Wi#  
public class TestMethod { j~.u>4  
jWh
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public TestMethod() F; 0Dp
 
{ ///xx/weblogic60b2_win.exe #|q;t   
try{ ,rXW`7!2  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /%;/pi  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $sM]BE:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ypxC1E  
fileFetch.start(); S;BP`g<l=  
} IG>>j}  
catch(Exception e){e.printStackTrace ();} ^T=5zqRD  
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} gl Li  
> d^r">!,  
} cRi A  
public static void main(String[] args) 7@3M]5:3g  
{ !SN6 ?Xy  
new TestMethod(); m[{nm95QZ  
} %N!h38N2  
} JW2W>6Dgv[  
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