http断点续传简单实现（java)

/*  ff9m_P  
**SiteFileFetch.java 0GMb?/
  
*/ +:A `e+\  
package NetFox; 6Dd>ex!-A  
import java.io.*; k_g@4x1y*  
import java.net.*; <?7CwW  
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public class SiteFileFetch extends Thread { mtUiO p  
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SiteInfoBean siteInfoBean = null; //文件信息Bean w+m7jn!$  
long[] nStartPos; //开始位置 5N9Cd[4  
long[] nEndPos; //结束位置 `JIp$  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9G6)ja?W  
long nFileLength; //文件长度 33`bKKO}  
boolean bFirst = true; //是否第一次取文件 P IG,a~  
boolean bStop = false; //停止标志 U=v>gNba  
File tmpFile; //文件下载的临时信息 >A
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DataOutputStream output; //输出到文件的输出流 .)*&NY!nsl  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） c{'Z.mut  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1dD%a91  
{ MpKXC  
siteInfoBean = bean; cg )(L;  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #m#IBRD:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &UDbH* !4=  
if(tmpFile.exists ()) G-CL \G\n  
{ D(z
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bFirst = false; U& GPe
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read_nPos(); mmQC9nZ  
}
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else Q_T,=y  
{ m.P F'_)/  
nStartPos = new long[bean.getNSplitter()]; ]n=z(2Z9lD  
nEndPos = new long[bean.getNSplitter()]; ?`TQ!m6y  
} o.$48h(  
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} J rK{MhO  
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public void run() s?<FS@k  
{ 58?WO}  
//获得文件长度 28JVW3&)  
//分割文件 s=$xnc}mf  
//实例FileSplitterFetch $%U}k=-  
//启动FileSplitterFetch线程 hl[<o<`Q  
//等待子线程返回
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try{ /{({f?k<\/  
if(bFirst) C,;?`3bH@  
{ !,-'wT<v  
nFileLength = getFileSize(); zGe =l;  
if(nFileLength == -1) 9u~C?w  
{ L^u|=9  
System.err.println("File Length is not known!"); ?23J(;)s  
} )^UqB0C6^  
else if(nFileLength == -2) dLQp"vs$  
{ +:m)BLA4l  
System.err.println("File is not access!"); @3eMvbI  
} \;%D;3Au  
else =ZH
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{ yI=nu53BV  
for(int i=0;i<nStartPos.length;i++) Z4z|B&  
{ (9bU\4F\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5I*1CIO  
} !:d\A  
for(int i=0;i<nEndPos.length-1;i++) #WA7}tHb  
{ Eoz/]
b  
nEndPos = nStartPos[i+1]; ym p*:
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} Bl)D/  
nEndPos[nEndPos.length-1] = nFileLength; '>OEQU5-  
} )1 @v<I  
} $_%  
?:q"qwt$F  
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//启动子线程 3{H!B&sb  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; jHMP"(]  
for(int i=0;i<nStartPos.length;i++) 9[t-W:3c7  
{ jKP75j
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w8>lWgN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2!f'l'}  
nStartPos,nEndPos,i); q.:a4w J  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0o6r3xc;  
fileSplitterFetch.start(); 5Bcmz'?!  
} X:FyNUa  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;J?fK69%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ^=I[uX-3ue  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", r?`nc6$0|  
nEndPos = " + nFileLength); 7|Qb}[s  
// fileSplitterFetch[nPos.length-1].start(); v&sp;%I6=  
cL
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WnQ'I=E#~  
//等待子线程结束 AzGbvBI&V  
//int count = 0; r
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//是否结束while循环 hAi'|;g  
boolean breakWhile = false; fk#Ggp<  
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dn  
while(!bStop) (1,4egMpR  
{ uxrNkZia  
write_nPos(); 4pDZ +}p  
Utility.sleep(500); Kd#64NSi$A  
breakWhile = true; PHsM)V+  
NFU=PS$  
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for(int i=0;i<nStartPos.length;i++) #.j:P#  
{ 9Up>e  
if(!fileSplitterFetch.bDownOver) Rlr[uU_  
{ Yk4ah$}%-^  
breakWhile = false; xoSBMf  
break; 6yaWxpW  
} p8y
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} )sEAPIka  
if(breakWhile) a(U/70j  
break; /[3!kW  
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I#yd/d5^  
//count++; wS2N,X/Y  
//if(count>4) u<@ 55k  
// siteStop(); V6<Ki  
} !OH'pC5  
BD ,3JDqT  
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System.err.println("文件下载结束！"); D@mqfi(x  
} t/"9LMKs?  
catch(Exception e){e.printStackTrace ();} ,"5p=JX`  
} <RkJ7Z^  
is-{U?-  
v2#qs*sW8  
//获得文件长度 Zfr?(y+3  
public long getFileSize() * 8D(Lp1  
{ el0W0T  
int nFileLength = -1; (7aE!r\Ab  
try{ Bq:: 5,v  
URL url = new URL(siteInfoBean.getSSiteURL()); 7"_gX  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =1kjKE !  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1n ZE9;o  
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64!V8&Ay  
int responseCode=httpConnection.getResponseCode(); !91<K{#A{  
if(responseCode>=400) ]_)=xF19  
{ HPWjNwM  
processErrorCode(responseCode); PJcz] <  
return -2; //-2 represent access is error #`Et{6WS  
} \=g%W^i  
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String sHeader; j@s,5:;[  
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for(int i=1;;i++) "V_PWEi  
{ _bq2h%G=8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Eh;~y*k\  
//Utility.log(in.readLine()); |c>A3 P$=B  
sHeader=httpConnection.getHeaderFieldKey(i); )6zwprH!  
if(sHeader!=null) HaamLu  
{ 65A>p:OO  
if(sHeader.equals("Content-Length")) e.g$|C^$m  
{ (3G]
-  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); k@R)_,2HH  
break; D#9W [6  
} KK*"s^L  
} w4+bzdZ  
else kjW`k?'s  
break; IF*k
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} hE/
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} Vi>kK|\b  
catch(IOException e){e.printStackTrace ();} $}7WJz:  
catch(Exception e){e.printStackTrace ();} KH&xu,I  
2?7a\s  
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Utility.log(nFileLength); l>9ZAI\^  
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return nFileLength; f&>Q6 {*]  
} B6Tn8@O  
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//保存下载信息（文件指针位置） ^Sr`)vP  
private void write_nPos() {4{ACp  
{ SIRZ_lt$r  
try{ >!YI7)  
output = new DataOutputStream(new FileOutputStream(tmpFile)); #6JCm!s  
output.writeInt(nStartPos.length); N1!|nS3w  
for(int i=0;i<nStartPos.length;i++) A]vQ1*pnk  
{ 3C8'@-U  
// output.writeLong(nPos); Z,,Wo %)o  
output.writeLong(fileSplitterFetch.nStartPos); x2T

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output.writeLong(fileSplitterFetch.nEndPos); j:,*Liz  
} ODM<$Yo:d  
output.close(); .,x08M  
} z|yC[Ota  
catch(IOException e){e.printStackTrace ();} ]IkjZ=  
catch(Exception e){e.printStackTrace ();} !NYc!gYD  
} *$_<| g)9  
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//读取保存的下载信息（文件指针位置） Da8qR+*x  
private void read_nPos() R16"lG  
{ T,gMc  
try{ ]?Ru~N}  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *pvhkJ g(  
int nCount = input.readInt(); }qXi;u))  
nStartPos = new long[nCount]; *-Y
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nEndPos = new long[nCount]; BZx#@356N  
for(int i=0;i<nStartPos.length;i++) A\.M/)Qo  
{ v1zJr6ra9  
nStartPos = input.readLong(); (85F1"Jp  
nEndPos = input.readLong(); <OW` )0UX  
} n4CzReG  
input.close(); J(-#(kMyf  
} zYj8\iER  
catch(IOException e){e.printStackTrace ();} Q_1EAxt  
catch(Exception e){e.printStackTrace ();} Vo(d)"m?  
} +]|J  
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private void processErrorCode(int nErrorCode) w];t]q|  
{ iygdX2  
System.err.println("Error Code : " + nErrorCode); 8'#%7+ "=!  
} R{6.O+j`  
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//停止文件下载 JT<Ia  
public void siteStop() >1mCjP  
{ o,Ew7~u  
bStop = true; XUUS N  
for(int i=0;i<nStartPos.length;i++) Khw!+!(H  
fileSplitterFetch.splitterStop(); Q:kpaMA1P  
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} o~^hsm[44J  
} {q8V
 
//负责部分文件的抓取 n2Ycq&O  
**FileSplitterFetch.java XX}RbE#4  
*/ >&U]j*'4  
package NetFox; n&
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import java.io.*; ~"}-cl,  
import java.net.*;  D
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public class FileSplitterFetch extends Thread { xp>ra2A  
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String sURL; //File URL b\VY)=U  
long nStartPos; //File Snippet Start Position &Cdk%@Tj]B  
long nEndPos; //File Snippet End Position
A@du*5>(  
int nThreadID; //Thread's ID ](-:l6  
boolean bDownOver = false; //Downing is over A*
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boolean bStop = false; //Stop identical Alp9] 0(  
FileAccessI fileAccessI = null; //File Access interface c<-_Vh.:5  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException i~.L{
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{ H`aqpa"C  
this.sURL = sURL; 1|n,s-  
this.nStartPos = nStart; kUn55 l  
this.nEndPos = nEnd; #$X_,P|D  
nThreadID = id; EQz`o+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 m/%sBw\rx  
} =f{V<i~q  
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public void run() gn#4az3@e>  
{ KS1Z&~4  
while(nStartPos < nEndPos && !bStop) [|xHXcW  
{ KDwjck"5;  
{Qg"1+hhM  
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try{ 6#KRI%adw`  
URL url = new URL(sURL); -`FTWH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); XNf%
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httpConnection.setRequestProperty("User-Agent","NetFox"); .& B_\*  
String sProperty = "bytes="+nStartPos+"-"; +KrV!Taf  
httpConnection.setRequestProperty("RANGE",sProperty); *" >ek k  
Utility.log(sProperty); 9eH(FB  
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InputStream input = httpConnection.getInputStream(); D#1'#di*t  
//logResponseHead(httpConnection); y
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5L"{J5R}  
| ?~-k[|  
byte[] b = new byte[1024]; wz$1^ml  
int nRead; \NDSpT<Z  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) '|G_C%,B  
{ a7)q^;:O  
nStartPos += fileAccessI.write(b,0,nRead); uw&GXOzew9  
//if(nThreadID == 1) Gyk>5Q}}  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qi.|oL9p  
} lnEc5J@c>i  
LwZBM
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#| `W ]  
Utility.log("Thread " + nThreadID + " is over!"); kZBIX
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bDownOver = true; 5Q^ L"&0  
//nPos = fileAccessI.write (b,0,nRead); -z-58FLlO  
} 'bN\bbR  
catch(Exception e){e.printStackTrace ();} #'mb9GWD3  
} J@=1zL  
} cH.T6u_%  
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//打印回应的头信息 4~53%=+  
public void logResponseHead(HttpURLConnection con) 4^1{UlCop  
{ R)?K+
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for(int i=1;;i++) \_#0Z+pX  
{ 5][Rvu0  
String header=con.getHeaderFieldKey(i); KwlN  
if(header!=null) f9cS^v_:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); p{"p<XFyO  
Utility.log(header+" : "+con.getHeaderField(header)); .Kv>*_
_-Q  
else &,4^LFZW  
break; 4d)w2t?H%  
} {6!Mf+Xq  
} Uq 2Uv  
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!u.{<51b  
public void splitterStop() KFor~A# D  
{ 0|nvi=4~e|  
bStop = true; Q*+@"tk<  
} Z~F% K~(  
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} *,-)4)7d  
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>|KfO>  
/* wb2N$Ew=  
**FileAccess.java O$J'BnPpw  
*//文件访问(定位，写) sTU]ntoQqR  
package NetFox; CsS0(n(x  
import java.io.*; l"p%]\tZ  
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public class FileAccessI implements Serializable{ L,of@>  
7Av/ZS  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 oOy@X =cw  
RandomAccessFile oSavedFile; "?Wwcd\  
long nPos; N6=cqUM wt  
8)&yjY  
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public FileAccessI() throws IOException BoG/Hd.S  
{ 64z9Yr@  
this("",0); Wxkk^J9F3  
} E
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=
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{H#1wu^]O$  
public FileAccessI(String sName,long nPos) throws IOException g2^7PtJg  
{ 1el?f>  
oSavedFile = new RandomAccessFile(sName,"rw"); HWT0oh]  
this.nPos = nPos;
l %=yT6  
oSavedFile.seek(nPos); "zc@(OA[z  
} ,RKBGOz?f  
xY(+[T!OF  
q<o*rcwf^  
public synchronized int write(byte[] b,int nStart,int nLen) K20n355uE  
{ M(HU^?B{'  
int n = -1; F8Z<JcOI  
try{ ~0w7E0DE[  
oSavedFile.write(b,nStart,nLen); 9m0`;~!  
n = nLen; 25BW/23}e  
} SJoQaR,)>  
catch(IOException e) JiEcPii  
{ %eGxQDIXg  
e.printStackTrace (); q#LwM]<.@>  
} >&
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it=L_zu}  
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return n; k^Zpb&`Hx  
} R?qVFMQ  
/%po@Pm#I  
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} `Gx"3ZUn  
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/* H$KE*Wwq  
**SiteInfoBean.java KSIH1E  
*/ @ v/%^  
package NetFox; E$.|h;i]Q  
N?Mmv|  
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public class SiteInfoBean { $5GvF1  
)wP0U{7?v  
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private String sSiteURL; //Site's URL cE 8vSQ%  
private String sFilePath; //Saved File's Path {.bLh0  
private String sFileName; //Saved File's Name cCFSPT2fq[  
private int nSplitter; //Count of Splited Downloading File , M/-lW  
B h@R9O<  
+'>N]|Z  
public SiteInfoBean() ,a?)#X  
{//nSplitter的缺省值为5 v|VY5vN  
//default value of nSplitter is 5 $1H?k  
this("","","",5); 2]eh[fRQ  
} /4#.qq0\{c  
TUJ]u2J8?  
|o~FKy1'z\  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) yZHQql%J O  
{ -4,qAnuMx  
sSiteURL= sURL; |4-c/@D.~  
sFilePath = sPath; t"2WJ-1k}  
sFileName = sName; _E)x
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this.nSplitter = nSpiltter; }CsUZ&*&  
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} I-kM~q_  
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~Az20RrK)  
public String getSSiteURL() vH# US  
{ < t>N(e  
return sSiteURL; `C=!8q  
} hrZ~7 0r  
)prpG !  
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public void setSSiteURL(String value) :J(a;/~ip  
{ IAnY+=^  
sSiteURL = value; ]!YzbvoR  
} gD=s~DgN)  
n+zXt?{u  
s]L`&fY]O  
public String getSFilePath() 1Na CGD"  
{ w#Nn(!VR  
return sFilePath; *2MUG h  
} F!pUfF,&  
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70HEu@-  
public void setSFilePath(String value) wH|\;M{0V1  
{ cB.v
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sFilePath = value; xhUQ.(S`r6  
} .a=M@;p  
E'XFn'  
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public String getSFileName() vm8QKPy  
{ B'
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return sFileName; HP]Xh~aP  
} 5uDQ*nJ|  
 `Yoafa  
G9E?   
public void setSFileName(String value) eDaVoc3  
{ ]PUyX8'~  
sFileName = value; .]r[0U  
} fD,#z&  
{y<_S]0  
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public int getNSplitter() lJ7k4ua\  
{ E8%O+x}  
return nSplitter; ]~ec]Y  
} !m_'<=)B4~  
/&kZ)XOi  
NKGo E/  
public void setNSplitter(int nCount) "Jv&=zJ  
{ tQ`tHe  
nSplitter = nCount; *:YW@Gbm  
} s)]|zu0"Ku  
} oWXvkDN   
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$#t&W&  
/* UKX'A)$  
**Utility.java /8Vh G|Wb  
*/ ^GRd;v=-@  
package NetFox; l8^^ O  
u=ENf1{ $>  

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public class Utility { Q|pz].0  
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public Utility() W:9L!+m^  
{ oO= 6Kd+T  
q=96Ci_a  
OsC1('4@  
} #}k^g:l1  
A;2?!i#f  
//线程睡眠 hTg%T#m  
public static void sleep(int nSecond) E"u>&uPH  
{ :j9;P7&"?  
try{ JY>]u*=  
Thread.sleep(nSecond); 2RM0ca_F  
} 7&T1RB'>  
catch(Exception e) )0UQy#r  
{ RQe#X6'h  
e.printStackTrace (); cT.1oaAM0  
} Gc SX5c  
} Qz/=+A/4  
;PLby]=O  
//日志 L\n_q6n  
public static void log(String sMsg) lT$A;7
[  
{ RJd55+h  
System.err.println(sMsg);
$vc:u6I[  
} >TtkG|/U-T  
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public static void log(int sMsg) ((t8  
{ 6'*?zZrz  
System.err.println(sMsg); seq S*^7  
} v)X1R/z5xw  
} j_ :4_zdBy  
/4=O^;  
srC'!I=s>8  
/* G]5'U"cj3  
**TestMethod.java C\EV$U,  
*/ .!=g  
package NetFox; ZM4q@O)/  
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public class TestMethod { yNI}=Z  
BU])@~$  
7G2TTa  
public TestMethod() Oja)J-QXb  
{ ///xx/weblogic60b2_win.exe =|uX?  
try{ &AlVJEI+  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); cV)C:!W2  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); QbS w<V  
SiteFileFetch fileFetch = new SiteFileFetch(bean); #9p{Y}2#  
fileFetch.start(); eK3J9;X  
} K3 "co1]u  
catch(Exception e){e.printStackTrace ();} 3LX<&."z  
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} ]y!|x_5c3  
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<W\~A$  
public static void main(String[] args) k(hes3JV  
{  :E'38~  
new TestMethod(); 8M:;9a8fh  
} O^oFH OpFh  
} Bz!ddAvlK  
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