http断点续传简单实现（java)

/* D=mU!rjr1  
**SiteFileFetch.java &"._%S58V  
*/ H.7gSB1  
package NetFox; r%xp^j}  
import java.io.*; jm =E_86_  
import java.net.*; z<+".sD'  
jHT4I>\  
//JF$o=)D  
public class SiteFileFetch extends Thread { F] +t/
 
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SiteInfoBean siteInfoBean = null; //文件信息Bean tRS^|??  
long[] nStartPos; //开始位置 k1L GT&  
long[] nEndPos; //结束位置 @!Il!+^3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9|v  
long nFileLength; //文件长度 BgA\l+  
boolean bFirst = true; //是否第一次取文件 HLN rI0  
boolean bStop = false; //停止标志 )"m FlS<I  
File tmpFile; //文件下载的临时信息 `-\4Dx1!q  
DataOutputStream output; //输出到文件的输出流 `kwyF27v]  
x~$P.X7(~  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &m5WmEz>`  
public SiteFileFetch(SiteInfoBean bean) throws IOException G 8uX[-L1  
{ tW|B\p}  
siteInfoBean = bean; 3HO4h\mp  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9K#.0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); +=$\7z>s  
if(tmpFile.exists ()) )P[B!  
{ v%/8pmZw;  
bFirst = false; $B~a*zZ7  
read_nPos(); !H~!i.m'-  
} z Rz#0  
else %N/I;`  
{ B6 x5E  
nStartPos = new long[bean.getNSplitter()]; J%aW^+O  
nEndPos = new long[bean.getNSplitter()]; CLQ\Is^]  
} \&R}JK  
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,$}P<WZMu  
} &m'O :ZS2  
*W(b=u  
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public void run() =WyAOgy}  
{ qI<*Cze  
//获得文件长度 bTA<AoW9="  
//分割文件 ^P"
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//实例FileSplitterFetch OMJr.u  
//启动FileSplitterFetch线程 eP&K]#  
//等待子线程返回 #@2`^1  
try{ 5Lum$C c}  
if(bFirst) H
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{ 7; TS  
nFileLength = getFileSize(); xdYjl.f  
if(nFileLength == -1) ;NRm ,  
{ t^8#~o!%  
System.err.println("File Length is not known!"); |g8 ]WFc  
} tI.(+-q  
else if(nFileLength == -2) jd]MC*%  
{ 9^igzRn0  
System.err.println("File is not access!"); BAzc'x&<  
} #xYkG5`lm  
else FE M_7M  
{ YyK9UZjI  
for(int i=0;i<nStartPos.length;i++) i;6\tK"!  
{ fkRb;aIl  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); +8Peh9"  
} /I[cj3}{+f  
for(int i=0;i<nEndPos.length-1;i++) !RiPr(m@y  
{ O-|RPW}  
nEndPos = nStartPos[i+1]; qaw5<
 
} _'2r=a#`  
nEndPos[nEndPos.length-1] = nFileLength; O~'1)k>  
} &+&^Hc  
} 7:bqh$3!s  
V X211U.Q  
=%2 E|/  
//启动子线程 ^,U&v;  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; }pTw$B  
for(int i=0;i<nStartPos.length;i++) <=A&y5o  
{
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c^Wm~"r  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), .P=!M  
nStartPos,nEndPos,i); ;R2(Gb
 
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yMo@ka=v  
fileSplitterFetch.start();
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} t{?_]2vl  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r9b`3yr=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); BOh&Db*  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", )>TA|W]@  
nEndPos = " + nFileLength); hrS/3c'<Z  
// fileSplitterFetch[nPos.length-1].start(); Kl+
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{qOSs,+=L  
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//等待子线程结束 l#Qf8*0  
//int count = 0; i>!f|<  
//是否结束while循环 U(J?Q  
boolean breakWhile = false; _10#rucr  
]}'WNy6c&x  
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while(!bStop) %>JqwMK  
{ )dlt$VX  
write_nPos(); *YtITyDS3>  
Utility.sleep(500); L G=Q  
breakWhile = true; uQ8
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fF *a/\h %  
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for(int i=0;i<nStartPos.length;i++) { ET+V  
{ 751\K`L  
if(!fileSplitterFetch.bDownOver) F,lQj7  
{ sZB$+~.:}  
breakWhile = false; ]+@b=J2b  
break; pl7!O9bo  
} ;dPLi4=o  
} cFH,fj  
if(breakWhile) Z/_RQ q   
break; >+$1 p_  
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y<#y3M!\  
//count++; vWj|[| <rX  
//if(count>4) v$,9l+p/  
// siteStop(); zL7+HY*3o  
} ,:;_j<g
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j~L{=ojz%  
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System.err.println("文件下载结束！"); Ymn0?$,D1=  
} cFuvi^n\  
catch(Exception e){e.printStackTrace ();}
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} *[ A%tj%  
a{H~>d<?  
wddF5EcK0  
//获得文件长度 vB#3jI  
public long getFileSize() ob0clJX  
{  ,?`$~8  
int nFileLength = -1; 3RGVH,  
try{ ))k^7g9M`  
URL url = new URL(siteInfoBean.getSSiteURL()); 0iHK1Pt}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;AHa|35\  
httpConnection.setRequestProperty("User-Agent","NetFox"); Uu3[Cf=C  
#n0P'@d,r  
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int responseCode=httpConnection.getResponseCode();
|\,e9U>  
if(responseCode>=400) C' ny 2>uA  
{ oOSw>23x  
processErrorCode(responseCode);
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return -2; //-2 represent access is error ]Nm_<%lT  
} iD{;!dUZ  
M22^.,Z  
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String sHeader; e;[/ytz"d'  
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for(int i=1;;i++)  "X}!j>-  
{ |\elM[G"g  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); L2Mcs  
//Utility.log(in.readLine()); JYKaF6bx8  
sHeader=httpConnection.getHeaderFieldKey(i); ?p6+?\H  
if(sHeader!=null) +#n[55d  
{ %tmK6cY4Y  
if(sHeader.equals("Content-Length")) 8l)^#"ySA  
{ iPI6 _h  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \@tt$ m%  
break; |} .Y&1@U  
} Elm/T]6  
} 2<|+h= &  
else +D$\^ <#  
break; gK`6NUj  
} xS*f{5Hr8  
} ^d4#  
catch(IOException e){e.printStackTrace ();} ~` #t?1SP  
catch(Exception e){e.printStackTrace ();} $t[`}I }  
Wh 8fC(BE  
idGM%Faur  
Utility.log(nFileLength); HJoPk'p%  
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return nFileLength; -1Tws|4gc  
} 4,TS1H  
:
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uFG]8pj2V1  
//保存下载信息（文件指针位置） &LHQ)?  
private void write_nPos() (<2PhJ|  
{ iK'bV<V&7  
try{ Oh-HfJyi  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )2u=U9  
output.writeInt(nStartPos.length); > : \lDz  
for(int i=0;i<nStartPos.length;i++) [C/h{WPC-  
{ >8oRO  
// output.writeLong(nPos); 7BdvJ"  
output.writeLong(fileSplitterFetch.nStartPos); [2.pZB  
output.writeLong(fileSplitterFetch.nEndPos); @dD70T  
} uRwIxT2  
output.close(); !x|OgvJ  
} ImyB4welo  
catch(IOException e){e.printStackTrace ();} ~vBmW_j  
catch(Exception e){e.printStackTrace ();} Y0aO/6  
} ep>S$a*|  
1}BW   
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//读取保存的下载信息（文件指针位置） }(O 7tC  
private void read_nPos() J{\S+O2,*  
{ @kRe0:t  
try{ ~z%K9YcyU  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *A;~~SQ  
int nCount = input.readInt(); >mi%L3P
k  
nStartPos = new long[nCount]; 8cF-kfbfZ  
nEndPos = new long[nCount]; ??ah  
for(int i=0;i<nStartPos.length;i++) *5.s@L( VU  
{ 4Z1-RS  
nStartPos = input.readLong(); cAV9.VS<L  
nEndPos = input.readLong();  lrU}_`  
} (]vHW+'  
input.close(); _(TavL>l =  
} =-1d m+P  
catch(IOException e){e.printStackTrace ();} f
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catch(Exception e){e.printStackTrace ();} v
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} WDWb7  
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private void processErrorCode(int nErrorCode) b~y1'|}g  
{ &5)Kg%r  
System.err.println("Error Code : " + nErrorCode); uhbo/7d'7  
} 0^?(;AK  
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 9 k)?-  
//停止文件下载 M)!8`]  
public void siteStop() i/NY86A  
{ FzXVNUMP  
bStop = true; c<r`E  
for(int i=0;i<nStartPos.length;i++) xT#j-T  
fileSplitterFetch.splitterStop(); 593D/^}D  
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c{ +Y$  
} JGHQ_AI  
} q{[}*%  
//负责部分文件的抓取 *.8@hPy  
**FileSplitterFetch.java Xd!=1::  
*/ e(@YBQ/Z  
package NetFox; C(Yk-7  
b
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import java.io.*; 6(f[<V!r  
import java.net.*; iL\<G} I  
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public class FileSplitterFetch extends Thread { #5-0R7
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_1VtVfiZ{  
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String sURL; //File URL Ia*eb%HG  
long nStartPos; //File Snippet Start Position ^PMP2\JQA  
long nEndPos; //File Snippet End Position ~Yv"
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int nThreadID; //Thread's ID T
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boolean bDownOver = false; //Downing is over XsQ?&xK=u  
boolean bStop = false; //Stop identical /lCn^E6-  
FileAccessI fileAccessI = null; //File Access interface EGf9pcUEO&  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException X<9jBj/t  
{ />S=Y"a/7  
this.sURL = sURL; P PZxH}J.  
this.nStartPos = nStart; #qi@I;;t  
this.nEndPos = nEnd; '=EaZ>=  
nThreadID = id; i:0~%X  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 SWvy<f4<  
} ;,}tXz  
0
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public void run() &]iX>m.  
{ I9h?Z&n5  
while(nStartPos < nEndPos && !bStop) -
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{ i|0H {q  
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try{ ;]34l."85  
URL url = new URL(sURL); a$.(Zl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &uI`Xq.  
httpConnection.setRequestProperty("User-Agent","NetFox"); /PN[g~3  
String sProperty = "bytes="+nStartPos+"-"; Q7zg i  
httpConnection.setRequestProperty("RANGE",sProperty); =ltT6of@o  
Utility.log(sProperty); ':lADUt  
%,Xs[[?i  
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InputStream input = httpConnection.getInputStream(); 'z0@|a  
//logResponseHead(httpConnection); 
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);$_|]#  
byte[] b = new byte[1024]; n,SDJsS^  
int nRead; T B~C4HK=  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "l6v[yv  
{ |f;u5r!^=  
nStartPos += fileAccessI.write(b,0,nRead); fmILkXKz  
//if(nThreadID == 1) v@TP_Ka  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ufd{.o[{-  
} Eqj&SA  
*6=2UJcJ  
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Utility.log("Thread " + nThreadID + " is over!"); AI}29L3C  
bDownOver = true; : &>PN,q>  
//nPos = fileAccessI.write (b,0,nRead); ~ \z7$9Q  
} 3QM6M9M  
catch(Exception e){e.printStackTrace ();} RI9&KS  
} 9E~=/Q=  
} @eu4W^W  
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//打印回应的头信息 ^3C8GzOsO  
public void logResponseHead(HttpURLConnection con) `3m7b!0k  
{ 2&7:JM~#  
for(int i=1;;i++) RuSKJ,T:9  
{ [Zc8tE2oN  
String header=con.getHeaderFieldKey(i); NK.]yw'  
if(header!=null) #lXwBfBMf  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); UPQ?vh2F2  
Utility.log(header+" : "+con.getHeaderField(header)); Y3^UJe7E  
else l0N~mes  
break; _3v6c  
} 706-
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} ]/&qv6D*d  
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public void splitterStop() r&6X|2@  
{ %X)w$}
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bStop = true; [xW;5j<87  
} xe9E</M_  
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=Ji+GJ<,9  
} lr[U6CJY  
,`kag~bZ  
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/* 5Us$.p  
**FileAccess.java =GH>-*qp  
*//文件访问(定位，写) TKJs'%Q7F6  
package NetFox; {yFCGCs  
import java.io.*; lsJl+%&8  
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&d}1)?  
public class FileAccessI implements Serializable{ ~^Ceru"<  
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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 :
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RandomAccessFile oSavedFile; 'YKyY:eZ  
long nPos; k2]fUP  
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public FileAccessI() throws IOException VS.~gHx  
{ +r8:t5:/I  
this("",0); :@x_& b  
} e'"2yA8dh"  
7nsn8WN[  
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public FileAccessI(String sName,long nPos) throws IOException QlxzWd3=q  
{ (tG8HwV-  
oSavedFile = new RandomAccessFile(sName,"rw"); 0<ze'FbV]  
this.nPos = nPos; GhlbYa  
oSavedFile.seek(nPos); u?Pec:3%  
} 'BUix!k0<  
b({K6#?'[  
0Wd2Z-I  
public synchronized int write(byte[] b,int nStart,int nLen) )-jA4!&  
{ Z|t`}lK  
int n = -1; X%>nvp  
try{ Dt#( fuk#  
oSavedFile.write(b,nStart,nLen); !!KA9mP  
n = nLen; V= wWY*C  
} A-6><X's6  
catch(IOException e) P]A~:Lj  
{ 4DwQ7KX  
e.printStackTrace (); $V/Hr/0  
} ?R!?}7  
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)G+D6s23  
return n; [}+h86:y  
} fo$s9g^<  
z<
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} XJSI/jpa@  
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/* p~A6:"8s`=  
**SiteInfoBean.java D!
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*/ Zws[C  
package NetFox; E*"-U!?)l2  
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public class SiteInfoBean { 7*MjQzg-P  
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?PSJQ3BC|  
private String sSiteURL; //Site's URL SHA6;y+U/~  
private String sFilePath; //Saved File's Path I9ZJ"29  
private String sFileName; //Saved File's Name hpBn_  
private int nSplitter; //Count of Splited Downloading File )b=m|
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T/Bx3VWL  
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public SiteInfoBean() ^ZD0rp(l  
{//nSplitter的缺省值为5 )e?6 Ncy  
//default value of nSplitter is 5 95IR.Qfn!  
this("","","",5);  m1#,B<6  
} 3E$h W  
X-']D_f|,  
(GJX[$@  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) .t9*wz  
{ vO 3-B   
sSiteURL= sURL; knABlU  
sFilePath = sPath; VthM`~3  
sFileName = sName; f1wwx|b%.  
this.nSplitter = nSpiltter; Fu
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u  
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} sOBuJx${m  
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public String getSSiteURL() o#frNT}  
{ Q39;bz
  
return sSiteURL; E>L_$J-A-  
} ]%<0V,G q  
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public void setSSiteURL(String value) F m$;p6&j  
{ &^JYIRn1\  
sSiteURL = value; |>Wi5h{6X  
} IEQ6J}L  
n1@ Or=5  
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public String getSFilePath() W}.p,d  
{ l EsE]f  
return sFilePath; 'k!V!wcD^y  
} Yvxp(  
3@^b's'S|}  
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public void setSFilePath(String value) h@D</2>  
{ ;h#nal>w@S  
sFilePath = value; pNzpT!}H>  
} ba"a!#wA
 
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public String getSFileName() !|;w(/  
{ gA~faje  
return sFileName; d){Al(/  
} liG3   
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public void setSFileName(String value) (??|\ &DTi  
{ %Q[+bN[/  
sFileName = value;
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} yi9c+w)b  
]Zz<9zix  
*
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public int getNSplitter() DU: sQS4  
{ rO`nS<G  
return nSplitter; k<3_!?3  
} 5`3f"(ay/  
b1{XGK'  
MB,P#7|  
public void setNSplitter(int nCount) sP NAG  
{ wOp# mT  
nSplitter = nCount; umWZ]8  
} n!(g<"  
} ]m(5>h#  
V6ioQx=K#  
xR,;^R|C  
/* 6c>tA2G|8  
**Utility.java :`ysq  
*/ UVD::  
package NetFox; ?JD\pYg[/  
%KmB>9  
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public class Utility { Px4zI9;cB  
V8xv@G{;  
:6z0Ep"  
public Utility() /m;w~-N  
{ qt}[M|Q^r  
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} +G_6Ek4  
o+
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//线程睡眠 j$]t`6gG  
public static void sleep(int nSecond) ++13m*fA  
{ 6iFd[<.*j  
try{ NG_O I*|~  
Thread.sleep(nSecond); ,U'Er#U  
} +>OEp
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catch(Exception e) 5hpb=2  
{ "7)F";_(^  
e.printStackTrace (); y( MF_'l  
} I01On>"@7  
} l{Hi5x'H  
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//日志 @Ds?  
public static void log(String sMsg) hpXu3o7e  
{ n37( sKG  
System.err.println(sMsg); Q$,8yTM  
} cx2s|@u0  
%1HW ) 7  
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public static void log(int sMsg) fD\h5`-  
{ %e%nsj6  
System.err.println(sMsg); 1"odkM  
} ]jHB'Y  
} }C#YR(]  
{=g-zsc]K  
o-O/MS
 
/* K)Db3JIIk  
**TestMethod.java z7PPwTBa  
*/ DO03vN  
package NetFox; il-&d]AP  
)X^nzhZ2O"  
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public class TestMethod { jQ`"Op 3  
8
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public TestMethod() >;
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{ ///xx/weblogic60b2_win.exe Wt3\&.n  
try{ 8:&@MZQ&!  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); W&!Yprr  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 0KDDAkR5R  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Pucf0 #  
fileFetch.start(); N{9<Tf*  
} 3mJHk<m8T  
catch(Exception e){e.printStackTrace ();} ZY/at/v  
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} s{q2C}=$?D  
@W @L%<  
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public static void main(String[] args) .M! (|KE4  
{ v%FV
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new TestMethod(); |;_ yAL  
} #SqOJX~Q  
} f(_qcgXp  
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