http断点续传简单实现（java)

/* G#'Q~N  
**SiteFileFetch.java 'hy?jQ'|e  
*/ $wgc vySx  
package NetFox; a0{[P$$  
import java.io.*; v*vn<nPAQ>  
import java.net.*; p}&Md-$1  
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public class SiteFileFetch extends Thread { Ia'x]
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SiteInfoBean siteInfoBean = null; //文件信息Bean }E,jR
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long[] nStartPos; //开始位置 Nr%(2[$ =  
long[] nEndPos; //结束位置 0K/G&c?;=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]
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long nFileLength; //文件长度 Hw y5G;  
boolean bFirst = true; //是否第一次取文件 JxnuGkE0[#  
boolean bStop = false; //停止标志 l:q8Pg)  
File tmpFile; //文件下载的临时信息 T G_bje  
DataOutputStream output; //输出到文件的输出流 CJv>/#$/F  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） _HLC>pH~#  
public SiteFileFetch(SiteInfoBean bean) throws IOException /%5_~Jkr,  
{ ;m''9z)2  
siteInfoBean = bean; E*OG-r   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); A3z/Bz4]:#  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); YWSz84d  
if(tmpFile.exists ()) =?HzNA$yh  
{ ,%[LwmET  
bFirst = false; J"5jy$30'$  
read_nPos(); =w?M_[&K)  
} ^l--zzO8l  
else zuk"  
{ cxY$LY!zX  
nStartPos = new long[bean.getNSplitter()]; >dyhox2*"  
nEndPos = new long[bean.getNSplitter()]; amMjuyW  
} (=`Z0)=  
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} {K<uM'ww>  
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public void run() 1B6C<cL:sU  
{ 8~.iuFp  
//获得文件长度 ';&0~[R[  
//分割文件 Q! Kn|mnN  
//实例FileSplitterFetch kkT3wP  
//启动FileSplitterFetch线程 kJI3`gS+  
//等待子线程返回 m5)EQE}gPp  
try{ xLe =d|6  
if(bFirst) E2Us#a  
{ @+iC/
  
nFileLength = getFileSize(); 4 #aqz9k  
if(nFileLength == -1) %)8d{1at  
{ Ica3  
System.err.println("File Length is not known!"); 4sb )^3T  
} .F4oo=
 
else if(nFileLength == -2) y+?=E g  
{ w~4 z@/^"p  
System.err.println("File is not access!"); HmhU
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} /X@7ju
;  
else :-w@^mli  
{ #m[vn^8B]y  
for(int i=0;i<nStartPos.length;i++) @55bE\E?@  
{ ^I@ey*$  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ]Mn&76fu  
} `<S/?I8  
for(int i=0;i<nEndPos.length-1;i++) ZEL/Ndk  
{ $< A8gTJ  
nEndPos = nStartPos[i+1]; ftO+.-sm<  
} {-o7w0d_  
nEndPos[nEndPos.length-1] = nFileLength; D}mo\  
} ^uC"
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} CKx\V+\O  
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c=jcvDQ6W  
//启动子线程 Uc\|X;nkRk  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; '&N: S-  
for(int i=0;i<nStartPos.length;i++) 2_Pz^L  
{ [&1iF1)4  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !O~},pp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8rGl&  
nStartPos,nEndPos,i); A,3@j@bdy  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =t@:F
 
fileSplitterFetch.start(); h~,x7]
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} }/_('q@s\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =ZCH1J5"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Y*`:M(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", nsZDZ/jx  
nEndPos = " + nFileLength); 8dr0 DF$c  
// fileSplitterFetch[nPos.length-1].start(); W3FymCI  
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//等待子线程结束 p^p'/$<6_  
//int count = 0; 2
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//是否结束while循环 U#8\#jo  
boolean breakWhile = false; D9}d]9]$  
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while(!bStop) )EhTM-1  
{ "g x5XW&  
write_nPos(); @:S$|D~  
Utility.sleep(500); TvQWdX=  
breakWhile = true; p3V9ikyy  
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for(int i=0;i<nStartPos.length;i++) r$b:1C~  
{ !JT<(I2  
if(!fileSplitterFetch.bDownOver) gUksO!7^1  
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breakWhile = false;  ~Y1"k]J  
break; Hi9 G^Q  
} B$K7L'e+-  
} p5lR-G  
if(breakWhile) ;e&hM\p  
break; Ytl:YzXCi  
o@qN#Mg?>}  
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//count++; =_#ye}E  
//if(count>4) &@mvw=d  
// siteStop(); Zr
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} {%]NpFg#b  
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System.err.println("文件下载结束！"); ?9o#%?6k  
} @/_
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catch(Exception e){e.printStackTrace ();} hXV4$Dai  
} /V#MLPA  
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//获得文件长度 T+&x{+gZ  
public long getFileSize() h1Ke$#$6  
{ sq8tv]  
int nFileLength = -1; N&R '$w  
try{ U92B+up-  
URL url = new URL(siteInfoBean.getSSiteURL()); f9h:"Dnzin  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); OlD7-c2L]  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0hHIz4(  
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int responseCode=httpConnection.getResponseCode(); nr'YWW  
if(responseCode>=400) |YG)NO  
{ "wc`fg"3  
processErrorCode(responseCode); [15hci+-  
return -2; //-2 represent access is error &*V0(  
} UiGUaBmF*  
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String sHeader; w]]x[D]L  
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for(int i=1;;i++) Li?{e+g  
{ @Z3[c[D)9  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &lXx0"-$  
//Utility.log(in.readLine()); ~2, wI<Nz  
sHeader=httpConnection.getHeaderFieldKey(i); Og&0Z)%  
if(sHeader!=null)
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{ F1Zk9%L%9$  
if(sHeader.equals("Content-Length")) \K4CbZ,.  
{ 1s^$oi}  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); kVB}r.NHP  
break; L!G9O]WB  
} ^>P@5gcoE(  
} 3rXL0&3w%  
else Ep v3/`I  
break; <.y^  
} O"2wV +9  
} |-cALQ  
catch(IOException e){e.printStackTrace ();} b&|YQW}~  
catch(Exception e){e.printStackTrace ();} hc@;}a\Y  
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Utility.log(nFileLength); he#Tr'j  
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return nFileLength; W~W?<%@  
} *aSRKY  
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//保存下载信息（文件指针位置） 6):sO/es  
private void write_nPos() 3'gd'`Hn/  
{ egIS rmL+X  
try{ 34O+#0<y~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); f|[5&,2<  
output.writeInt(nStartPos.length); 4n.i<K8K[  
for(int i=0;i<nStartPos.length;i++) lHj7O&+  
{ 9X^-)G>  
// output.writeLong(nPos); J^<j=a|D  
output.writeLong(fileSplitterFetch.nStartPos); epY;1,;>  
output.writeLong(fileSplitterFetch.nEndPos); b
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} a#^4xy:  
output.close(); c_DB^M!h  
} K{[Fa,]'  
catch(IOException e){e.printStackTrace ();} Z{R=h7
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catch(Exception e){e.printStackTrace ();} .+yJh  
} EC\rh](d 1  
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//读取保存的下载信息（文件指针位置） D$
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private void read_nPos() =f{Z~`3  
{  }@Ll!
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try{ tg m{gR  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,y{fqa4  
int nCount = input.readInt(); 5G]#'tu  
nStartPos = new long[nCount]; COl%P  
nEndPos = new long[nCount]; d+$[EDix  
for(int i=0;i<nStartPos.length;i++) (}7o a9Q<  
{ \2LA%ZU  
nStartPos = input.readLong(); ,~68~_)  
nEndPos = input.readLong(); Se]t;7j  
} <3]/ms  
input.close(); .q& ]wu  
} HpgN$$\@  
catch(IOException e){e.printStackTrace ();} P^{`d_[K%  
catch(Exception e){e.printStackTrace ();} =_~'G^`tu  
} t+Tg@~K2[>  
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private void processErrorCode(int nErrorCode) @0x.n\
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{ (V|q\XS  
System.err.println("Error Code : " + nErrorCode); !*QA;*e  
} C&MqUj"]  
}v|[h[cZ  
]r{#268  
//停止文件下载 l9Cy30O6  
public void siteStop() &wWGZ~T  
{
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bStop = true; b*%WAVt2T  
for(int i=0;i<nStartPos.length;i++) b|pNc'u:Cn  
fileSplitterFetch.splitterStop(); dIh(~KqB  
#JT%]!  
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} _\V{X}ftqa  
}  kc/H  
//负责部分文件的抓取 LAjw!QB  
**FileSplitterFetch.java mjJlXA  
*/ 3 mMdq*X5  
package NetFox; a*ixs'MJ  
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import java.io.*; Z-r0 D  
import java.net.*; g
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public class FileSplitterFetch extends Thread { bsS|!KT  
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String sURL; //File URL ,}xC) >  
long nStartPos; //File Snippet Start Position J'&?=|  
long nEndPos; //File Snippet End Position )pj \b[  
int nThreadID; //Thread's ID 'aSORVq^e[  
boolean bDownOver = false; //Downing is over 78}%{7YY  
boolean bStop = false; //Stop identical =:T:9Y_i  
FileAccessI fileAccessI = null; //File Access interface ,PtR^" Mf4  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException e@MCumc~+  
{ $7ME a"a  
this.sURL = sURL; %-zH]"Q$  
this.nStartPos = nStart; =>TtX@Q{  
this.nEndPos = nEnd; $TUC?e9"h  
nThreadID = id; w@D@,q'x  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 >}`1'su  
} '3,JL!  
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public void run() Wa<NId  
{ t"m`P1  
while(nStartPos < nEndPos && !bStop) Z-=7QK.\{  
{ &]A1 _dy  
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try{ Lgw@y!Llij  
URL url = new URL(sURL); kxiyF$ 9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +Gs;3jC^  
httpConnection.setRequestProperty("User-Agent","NetFox"); m^&mCo,  
String sProperty = "bytes="+nStartPos+"-"; *^m.V=  
httpConnection.setRequestProperty("RANGE",sProperty); ?9M+fi  
Utility.log(sProperty); B,qZwc|  
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InputStream input = httpConnection.getInputStream(); 81 Not  
//logResponseHead(httpConnection); oieLh"$  
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byte[] b = new byte[1024]; tg4&j$  
int nRead; c8 fb)`,k  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) w'j]Y%  
{ !,WRXE&j  
nStartPos += fileAccessI.write(b,0,nRead); F}mwQ%M  
//if(nThreadID == 1) t$Ji{t-  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Z%d4V<fn  
} ]nGA1S{  
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Utility.log("Thread " + nThreadID + " is over!"); {:+^[rerj  
bDownOver = true;
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//nPos = fileAccessI.write (b,0,nRead); Y'":OW#oN  
} v2<gkCK^  
catch(Exception e){e.printStackTrace ();} rW .0_*  
} 6:X\vw  
} l"g%vS,;`  
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//打印回应的头信息 f)fw87UPc  
public void logResponseHead(HttpURLConnection con) alD|-{Bf  
{ >}tG^)os  
for(int i=1;;i++) m$j;FKz+|  
{ ImW~J
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String header=con.getHeaderFieldKey(i); e/%YruzS  
if(header!=null) rx)Q]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); -B! TA0=oJ  
Utility.log(header+" : "+con.getHeaderField(header)); k18V4ATE]  
else vK/Z9wR*05  
break; WWzns[$f  
} oMf h|B  
} l$@lk?dc  
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public void splitterStop() q&x#S
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{ "lAS <dq  
bStop = true; FV,SA3  
} mjc:0hH  
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} iIRigW  
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%^A++Z$`  
/* qa#F}aGd  
**FileAccess.java ^DJU99   
*//文件访问(定位，写) T!$HVHh&,}  
package NetFox; LZ$!=vg4  
import java.io.*; Qk?Jy<Ra  
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public class FileAccessI implements Serializable{ [X\2U4  
b&&'b)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 w%na n=  
RandomAccessFile oSavedFile; cE?
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long nPos; yx4c+(J^8  
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public FileAccessI() throws IOException qN(;
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{ pm|]GkM  
this("",0); 3j#F'M)s{  
} *2hzReM  
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public FileAccessI(String sName,long nPos) throws IOException )`0 j\  
{ kv2:rmv  
oSavedFile = new RandomAccessFile(sName,"rw"); H%V[% T4=  
this.nPos = nPos; 3iwZUqyq  
oSavedFile.seek(nPos); 7?@v}%w  
} <ZEll[0L  
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w?"l4.E%  
public synchronized int write(byte[] b,int nStart,int nLen) ->UrWW^  
{ v.J#d>tvf  
int n = -1; zc5_;!t  
try{ }2"k:-g  
oSavedFile.write(b,nStart,nLen); s6IuM )x  
n = nLen; *O2j<3CHf  
} uLht;-`{n  
catch(IOException e) r6<}S(  
{ $tJJ >"  
e.printStackTrace (); 2q bpjm  
} (
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return n; XFYl[?`G  
} X8TZePh  
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} 1:8: yFV  
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/* Q2uE_w`B  
**SiteInfoBean.java V2X(f6v  
*/ -fv.ByyA  
package NetFox; J %t1T]y~  
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public class SiteInfoBean { I._=q  
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=r2d{  
private String sSiteURL; //Site's URL H'.d'OE:I  
private String sFilePath; //Saved File's Path -mF9S
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private String sFileName; //Saved File's Name mBF?+/l  
private int nSplitter; //Count of Splited Downloading File &3efJ?8  
7Fx8&Z  
#,Y}  
public SiteInfoBean() r`@Dgo}  
{//nSplitter的缺省值为5 IYFA>*Es  
//default value of nSplitter is 5 FdD'H
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this("","","",5); L $
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} lHU$A;  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) g`1i[Iu2  
{ N C&1l]  
sSiteURL= sURL; 4$rO,W/&0  
sFilePath = sPath; |qD<h  
sFileName = sName; s.U p<Rw  
this.nSplitter = nSpiltter; @{G(.S  
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} j!l(ReGb  
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public String getSSiteURL() *!/
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{ ScD9Ct*):C  
return sSiteURL; n9%rjS$  
} D+U^ pl-  
_1a2Z\  
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public void setSSiteURL(String value) h ? M0@Z  
{ sq%f%?(V  
sSiteURL = value; 0IZV4{  
} vzU%5,  
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public String getSFilePath() PSE![whK  
{ 7?
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return sFilePath; f"Z2&Y@  
} k`d  
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public void setSFilePath(String value) VC@o]t5  
{ eP)RP6ON{  
sFilePath = value; *QLbrR  
} q^s$4q  
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public String getSFileName() E4{8 $:q=  
{ \,WPFV  
return sFileName; GM5::M]fS  
} mxIEg?r(  
m{g{"=}YR  
<D__17W:;  
public void setSFileName(String value) 1~+w7Ar=(  
{ 5)vXmAD/0  
sFileName = value; l"+=z.l6;  
} bvoR?D\-"  
x
n-n{U"  
#pZ3xa3R  
public int getNSplitter() 8ydOS  
{ 6l4l74  
return nSplitter; p(v.sP4w  
} QAR<.zXvP  
(b(iL\B$D=  
MKbW^:  
public void setNSplitter(int nCount) \oi=fu=}*  
{ *+ 7#z;
  
nSplitter = nCount; <
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} 7L!k9"X`0F  
} h:|aQJG5  
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A 9u9d\  
/* #pIb:/2a_  
**Utility.java [mm5?23g  
*/ P6MT[  
package NetFox; *+b[v7  
$ZA71TzMV  
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public class Utility { <+6)E@Y  
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8NLk`/  
public Utility() Eq|_>f@@8  
{ :S.0e  
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} E]68IuP@'  
s>kzt1,x  
//线程睡眠 v8LKv`I's  
public static void sleep(int nSecond) )0NA*<Q+.  
{ us/x.qPy2  
try{ n04Zji(F@  
Thread.sleep(nSecond); k'm!|  
} HxkhlNB  
catch(Exception e) spJB6n(  
{ #q%&,;4  
e.printStackTrace (); c(o8uWn
  
} oM< 9]jK}  
} IkD\YPL;  
.7oz  
//日志 [z?<'Tj  
public static void log(String sMsg) BsxQW`>^y  
{ f;QWlh"9  
System.err.println(sMsg); NbSwn}e_  
} f@Db._E  
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myH#.$=A  
public static void log(int sMsg) !bQ5CB  
{ zE<}_nA  
System.err.println(sMsg);  MgA6/k  
} 8}4V
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} 9]l7j\L  
m#Rll[  
O4 [[9  
/* {4 *ob@w*  
**TestMethod.java 
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*/ fk=_ Y  
package NetFox; ucyxvhH^-  
0rF{"HM~  
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public class TestMethod { /KH3v!G0  
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8USF;k  
public TestMethod() euQ
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{ ///xx/weblogic60b2_win.exe Fe8xOo6  
try{ 3rs=EMz:w  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >*EcX
3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); E:#VS~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 7,Nd[ oL*7  
fileFetch.start(); k{uc%6s  
} V0"UFy?i  
catch(Exception e){e.printStackTrace ();} JWC{"6  
!YCYmxw#  
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} !x[+rf  
D/rKqPp|!  
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public static void main(String[] args) Y
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{ dKhDO`.s  
new TestMethod(); Y!}BmRLh2  
} {R\"x|  
} aabnlOVw  
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