http断点续传简单实现（java)

/* d:&=|k
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**SiteFileFetch.java VlbS\Y.  
*/ NG\g_^.M
 
package NetFox; !Sj
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import java.io.*; LEn+0^hX  
import java.net.*; }T1.~E  
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public class SiteFileFetch extends Thread { 5!V%0EQqw  
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SiteInfoBean siteInfoBean = null; //文件信息Bean efUa[XO  
long[] nStartPos; //开始位置 (JI[y"2  
long[] nEndPos; //结束位置 <%ba 3<sg  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Zog&:]P'F  
long nFileLength; //文件长度 kC8M2|L  
boolean bFirst = true; //是否第一次取文件 6i7
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boolean bStop = false; //停止标志 Je &O  
File tmpFile; //文件下载的临时信息 h*B7UzCg  
DataOutputStream output; //输出到文件的输出流 >HL$=J_K?  
]X\p\n'@j  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） j[Z<|Da  
public SiteFileFetch(SiteInfoBean bean) throws IOException p"tCMB  
{ Zp qb0ro  
siteInfoBean = bean; \6L,jSoBl  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /#-zI#iK  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); +rWcfXOHM  
if(tmpFile.exists ()) ]@wKm1%v  
{ G;he:Bf  
bFirst = false;  P0<)E  
read_nPos(); a1 v%G  
} r(OH  
else q#_<J1)z  
{ 4`zK`bRcK#  
nStartPos = new long[bean.getNSplitter()]; PfjD!=yS=h  
nEndPos = new long[bean.getNSplitter()]; Lu5lpeSQ  
} ~jD~_JGp  
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} ,R[<+!RS  
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public void run() WGA"e  
{ $Y?[[>u  
//获得文件长度 S5/p3;O\c  
//分割文件 TH>7XK<90M  
//实例FileSplitterFetch 0lLg uBW@  
//启动FileSplitterFetch线程 *3#RS  
//等待子线程返回 -GODM128 ^  
try{ [vn"r^P  
if(bFirst) w~ O)DhC  
{ k2:mIp\  
nFileLength = getFileSize(); siz:YRur  
if(nFileLength == -1) U[G5<&Z
^  
{ q854k+C  
System.err.println("File Length is not known!"); C:ntr=3J  
} @r]1;KG  
else if(nFileLength == -2) 1EQLsg`d^  
{ HE@P<  
System.err.println("File is not access!"); ZO&F15$P  
} Sh(XF
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else qdxDR 2]U  
{ Lm7fz9F%
 
for(int i=0;i<nStartPos.length;i++) kb[+II  
{ '@f#GNRT  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 4\y>pXML-U  
} ofuQ`g1hb  
for(int i=0;i<nEndPos.length-1;i++) J5SOPG  
{ 3Gt@Fo=  
nEndPos = nStartPos[i+1]; rq|>z.  
} 9d8U
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nEndPos[nEndPos.length-1] = nFileLength; ]~7xq)28  
} uO4R5F|tL  
} kY#sQz}8  
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//启动子线程 Nrzg>WQa  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Y|L]#  
for(int i=0;i<nStartPos.length;i++) W<M\b#  
{ `g'z6~c7n  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [t"#4[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), QA#Jx  
nStartPos,nEndPos,i); w%eEj.MI|i  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $}.#0c8I  
fileSplitterFetch.start(); w"OeS;#e:  
} 7vEZb.~4z  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .`+N+B(4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); X_#,5t=7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", +A<7:`sO  
nEndPos = " + nFileLength); <v$yXA  
// fileSplitterFetch[nPos.length-1].start();
;w^{PZBg  
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//等待子线程结束 &u0on)E  
//int count = 0; g/O
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//是否结束while循环 ;\gHFG}  
boolean breakWhile = false;  S/Gy:GIf  
7-[^0qS  
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while(!bStop) B2)SNhF2Y  
{ ~%u;lr  
write_nPos(); 7_ao?}g  
Utility.sleep(500); |"k+j_/+  
breakWhile = true; z>O=. Ku6  
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for(int i=0;i<nStartPos.length;i++) (zhi/>suG  
{ wj|[a,(r  
if(!fileSplitterFetch.bDownOver) 'L ]k\GO  
{ uOQl;}Lk5  
breakWhile = false; Y1L7sH 9  
break; @
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} n]snD1?KX  
} IGcYPL\&  
if(breakWhile) j4!oBSp  
break; dS~#Lzm  
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mE3M$2}  
//count++; k+y>xI,  
//if(count>4) 1|3{.Ed  
// siteStop(); afj[HJbY  
} ~"i4"Op&  
KcF#c_f   
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System.err.println("文件下载结束！"); KPB^>,T2{  
} ^HI}bS1+|  
catch(Exception e){e.printStackTrace ();} [E4#|w  
} h-=lZ~W~  
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//获得文件长度 Q*
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public long getFileSize() 9{XC9\~
 
{ br_D Orq|  
int nFileLength = -1; zIh`Vw,t0  
try{ ^{w]r5d  
URL url = new URL(siteInfoBean.getSSiteURL()); 6qkMB|@Ix  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Tq`rc"&7u  
httpConnection.setRequestProperty("User-Agent","NetFox"); PxiJ R[a  
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int responseCode=httpConnection.getResponseCode(); 9M!J7 W  
if(responseCode>=400) $ru()/pI)z  
{ |%xgob  
processErrorCode(responseCode); ^E`SR6_cmj  
return -2; //-2 represent access is error k\`~v$R3  
} C6cEt5  
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#JIh-h@  
String sHeader; (2fWJ%7VG  
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for(int i=1;;i++) y?*4SLy
 
{ *='J>z.]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); v6q oH)n  
//Utility.log(in.readLine()); ^P !}
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sHeader=httpConnection.getHeaderFieldKey(i); w5tcO%+k1  
if(sHeader!=null) k x26nDT(  
{ 
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if(sHeader.equals("Content-Length")) -VVJf5/  
{ sAec*Q(R  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); K:\db'``  
break; N5\]VCX  
} }:2GD0Ru  
} smTPca)7s  
else  YD|;xuh  
break; WfF~\DlrD  
} 896oz>  
} #`(-Oj2hH  
catch(IOException e){e.printStackTrace ();} C`LHFqv  
catch(Exception e){e.printStackTrace ();} c.;}e:)s  
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Utility.log(nFileLength); N,M[Opm  
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return nFileLength; 0M_~@E*&  
} oYn|>`+6:y  
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//保存下载信息（文件指针位置） 3+
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private void write_nPos() ?f\ ~:Gm/  
{ 48 n5Y~YS  
try{ #'&&&_Hu3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); zm7IkYF  
output.writeInt(nStartPos.length); )J<VDO:_YA  
for(int i=0;i<nStartPos.length;i++) ta'{S=^j  
{ 6b6rM%B.oD  
// output.writeLong(nPos); `: R7jf  
output.writeLong(fileSplitterFetch.nStartPos); ]W9{<+&  
output.writeLong(fileSplitterFetch.nEndPos); v3q.,I_  
} .Fe_Z)i>h  
output.close(); %{*A@jQsg  
} n |e=7?H8  
catch(IOException e){e.printStackTrace ();} 2YV*U_\L  
catch(Exception e){e.printStackTrace ();} 6*uWRjt  
} ,N`cH\  
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//读取保存的下载信息（文件指针位置） ~p* \|YC  
private void read_nPos() Y:-O/X  
{ nA)KRCi
 
try{ $YztLcn  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )U5Ba^"fI  
int nCount = input.readInt(); L$ki>._i\  
nStartPos = new long[nCount]; L63B# H"  
nEndPos = new long[nCount]; $ctpg9 7  
for(int i=0;i<nStartPos.length;i++) px>g  
{ ];63QJU  
nStartPos = input.readLong(); Mr6q7  
nEndPos = input.readLong(); (S)jV0  
} VTIRkC wl@  
input.close(); XKQ\Ts2<k  
} *MM8\p_PuT  
catch(IOException e){e.printStackTrace ();} y|Vwy4tK9  
catch(Exception e){e.printStackTrace ();} sb"h:i>O4  
} 7~ =r9-&G  
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private void processErrorCode(int nErrorCode) k,0lA#>  
{ g3Z"ri~!G  
System.err.println("Error Code : " + nErrorCode); U6K!FOND  
} t*dd/a  
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/)/>/4O  
//停止文件下载 7S.E,\Tws  
public void siteStop() 7:$zSj#y  
{ ]rMHO  
bStop = true; 'eDV-cB  
for(int i=0;i<nStartPos.length;i++) :211T&B%A_  
fileSplitterFetch.splitterStop(); >m'n#=yap  
A=bBI>GEYP  
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} hreG5g9{  
} sRaTRL2  
//负责部分文件的抓取 </-aG[Fi  
**FileSplitterFetch.java ibL   
*/ XZH\HK)K-]  
package NetFox; Q8?:L<
A  
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import java.io.*; rfHAz  
import java.net.*; F$nc9x[S  
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public class FileSplitterFetch extends Thread { =QJI_veUG`  
>))K%\p   
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String sURL; //File URL _,bDv`>Ra  
long nStartPos; //File Snippet Start Position 'Fr"96C$  
long nEndPos; //File Snippet End Position w7`09oJm  
int nThreadID; //Thread's ID \Jm^XXgS  
boolean bDownOver = false; //Downing is over #CTeZ/g  
boolean bStop = false; //Stop identical Xcw6mpLt  
FileAccessI fileAccessI = null; //File Access interface 'wd&O03&  
Y wu > k  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException xjH({(/B>a  
{ [/GCy0jk  
this.sURL = sURL; T))F r:  
this.nStartPos = nStart; "fOxS\er  
this.nEndPos = nEnd; g\Akf  
nThreadID = id; $9rQ w1#e  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 k4+Q$3"  
} Sgq" 3(+%,  
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public void run() 7QM1E(cMg  
{ Wo+^R%K'4  
while(nStartPos < nEndPos && !bStop) q:<vl^<j  
{ E@CK.-N|  
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try{ 6~tj"34_  
URL url = new URL(sURL); gtRVXgI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); q"Th\? }%  
httpConnection.setRequestProperty("User-Agent","NetFox"); P]<15l  
String sProperty = "bytes="+nStartPos+"-"; Kdr}7#c  
httpConnection.setRequestProperty("RANGE",sProperty); > K s.  
Utility.log(sProperty); 3S{
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InputStream input = httpConnection.getInputStream(); V#TNv0&0  
//logResponseHead(httpConnection); Xz\X 8I  
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byte[] b = new byte[1024]; "w{$d&+?ag  
int nRead; nQ08(8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) CS\8ej}y  
{ ",P?jgs^g5  
nStartPos += fileAccessI.write(b,0,nRead); &}!AjA)  
//if(nThreadID == 1) 7=a=@D[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); g>;"Fymc'  
} F!zGk(Pu  
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(N?nOOQ  
Utility.log("Thread " + nThreadID + " is over!"); EL(BXJrx{  
bDownOver = true;  I|
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//nPos = fileAccessI.write (b,0,nRead); x\aCZ  
} &/8B(0<  
catch(Exception e){e.printStackTrace ();} V?"1&m&E  
} He1~27+99  
} Wn&9R j  
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//打印回应的头信息 *0x!C8*`Xe  
public void logResponseHead(HttpURLConnection con) &"d :+!4h  
{ JfRqOEP4Y  
for(int i=1;;i++) A9y@v{tx
N  
{ %J+k.UrM  
String header=con.getHeaderFieldKey(i); &neB$m3y  
if(header!=null) L~*nI d  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Au"BDP  
Utility.log(header+" : "+con.getHeaderField(header)); 9qm'qx  
else J3hhh(  
break; 6W9lKD_i  
} ';LsEI[  
} y\Wp}}  
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public void splitterStop() # blh9.V&F  
{ @ 1FWBH~  
bStop = true; 
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} HpS1(%d"  
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} c=<^pCa9t1  
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/* 5
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**FileAccess.java ~*L
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*//文件访问(定位，写) S+l>@wa)|  
package NetFox; O@>{%u  
import java.io.*; z8 K#G%,:  
kfq<M7y  
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public class FileAccessI implements Serializable{ u?KG%  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -v=tM6  
RandomAccessFile oSavedFile; Vu,:rPqI  
long nPos; ?uXY6J"  
p7[&H/  
>Sm#-4B-  
public FileAccessI() throws IOException *-gmWATC6  
{ e r"gPW  
this("",0); 2G$-:4B  
} ~
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public FileAccessI(String sName,long nPos) throws IOException ]%UAN_T  
{ ^@]yiED{g  
oSavedFile = new RandomAccessFile(sName,"rw"); )T@+"Pw8t  
this.nPos = nPos; to)Pl}9QkK  
oSavedFile.seek(nPos); /_r{7Gq.  
} kaVYe)~  
>c.HH}O0W  
||.Ve,<:  
public synchronized int write(byte[] b,int nStart,int nLen) nG"Ae8r  
{ #b{;)C fL  
int n = -1; g'V,K\TG  
try{ ;MjOs&1f0K  
oSavedFile.write(b,nStart,nLen); w4Ku1G#jC  
n = nLen; #4!6pMW(&7  
} %xt\|Lt  
catch(IOException e) \>4x7mF!  
{ 'deqF|Iox  
e.printStackTrace (); Dz+R Q`Vn  
} sUsIu,1Q  
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4  
return n; S]biN]+7s  
} }Yp]A  
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~

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} 6Q9S~YYq  
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/* Mhg_z.Z  
**SiteInfoBean.java 7 *HBb-  
*/
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package NetFox; uJ/&!q<3  
+)TOcxF%  
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public class SiteInfoBean { NeY,Of|  
l%$co07cX  
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private String sSiteURL; //Site's URL )NS&1$  
private String sFilePath; //Saved File's Path )F4P-u  
private String sFileName; //Saved File's Name d!]_n|B@9  
private int nSplitter; //Count of Splited Downloading File P[C03a!lXg  
8&9'1X5)8_  
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public SiteInfoBean() h^"OC$  
{//nSplitter的缺省值为5 4vRIJ}nQ  
//default value of nSplitter is 5 ?]u=5gqUU  
this("","","",5); m;KD@E!  
} :u>9H{a  
>pn5nn1a  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) %{M&"Mv  
{ 9~$'?  
sSiteURL= sURL; vS'5Lm  
sFilePath = sPath; VCUEz
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sFileName = sName; Ro|%pT  
this.nSplitter = nSpiltter; p8Wik<'^  
+=A53V[C  
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} ON<X1eU  
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public String getSSiteURL() Zm!5X9^!  
{ @-QDp`QtI  
return sSiteURL; {y k0Zef_  
} c*#*8R9.y  
{
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public void setSSiteURL(String value) -<tfbaA  
{ R87e"m/C%  
sSiteURL = value; kX^Y{73  
} MKN],l N  
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public String getSFilePath() {g(
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{ k)l^;x-  
return sFilePath; evBr{oi@  
} ;,yjkD[mWE  
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h!L6NS_Q,  
public void setSFilePath(String value) 5==}8<$  
{ 7#BUd/  
sFilePath = value; 8Ekk"h6  
} 9AsK=/Buf  
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public String getSFileName() aA-gl9  
{ /{9"O y7E  
return sFileName; VV1I2YcKt  
} D!oELZ3  
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_s_%}8
o  
public void setSFileName(String value) _V`Gmy[]p  
{ PnKgUJoa0  
sFileName = value; Dr!g$,9  
} J~jR`2+r  
4/Yk;X[jk  
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public int getNSplitter() ][y~(&=T  
{ %;r0,lN|II  
return nSplitter; 18AKM  
} Oa'DVfw2J  
l?N|Gj;ZFZ  
9y~5@/32R  
public void setNSplitter(int nCount) 2V1|b`b#4  
{ DhAQ|SdCf  
nSplitter = nCount; f2JeXsOI  
} !Cpy )D(  
} /*+P}__k  
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uq>\pO&P  
/* Vu/{Hr  
**Utility.java E26zw9d  
*/ v^=Po6S[{+  
package NetFox; #]iSh(|8  
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public class Utility { (W~')A"hC'  
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public Utility() \Tc<27-  
{ f8T6(cA  
JfJLJ(}  
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} :/c40:[  
J 8z|ua  
//线程睡眠 GI~JIXHTQ  
public static void sleep(int nSecond) dOm@cs  
{ x.+r.cAXH  
try{ s+@+<QE  
Thread.sleep(nSecond); ^ucmScl  
} /Ria"lLv  
catch(Exception e) pf\ Ybbs  
{ ,eI2#6w|C  
e.printStackTrace (); KlMSkdmW  
} Dsl,(qm5  
} EpX.{B@B_[  
qT<OiIMj^  
//日志 ;i)NP X  
public static void log(String sMsg) i#&iT P`  
{ K@JGGgrE`!  
System.err.println(sMsg); !O`a
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} +b =X~>vZ  
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q X"Pg  
public static void log(int sMsg) sew0n`d1  
{ FZvh]ZX  
System.err.println(sMsg); ftr8~*]O  
} _~l*p"PL<  
} }f l4^F  
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/* 5~,/VV  
**TestMethod.java 4Y2!q$}I+  
*/ .T>^bLuFy  
package NetFox; 8_d>=*(  
#nD]G#>e  
L
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public class TestMethod { U_&v|2o#3  
ul-A'  
kBRy(?Mft&  
public TestMethod() j(QK0"z  
{ ///xx/weblogic60b2_win.exe W$>AK_Y}  
try{ <>Nq]WqA  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `y^tCJ2u*  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); e5GJ:2sH  
SiteFileFetch fileFetch = new SiteFileFetch(bean); kKFhbHUZa  
fileFetch.start(); V-7A80!5  
} fz[-pJ5[  
catch(Exception e){e.printStackTrace ();} f\|R<3 L  
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m  
} ZLS\K/F>>=  

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public static void main(String[] args) Y)ig:m]#  
{ >!gW]{  
new TestMethod(); K:JM*4W  
} -s!cZ3  
} }#Q?\  
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