http断点续传简单实现（java)

/* nsT]Yxo%M  
**SiteFileFetch.java K4T#8K]aZF  
*/ !Cqm=q{K  
package NetFox; -Iq W@|N  
import java.io.*; yH`4sd  
import java.net.*; IE;Fu67wi  
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public class SiteFileFetch extends Thread { }s*H|z  
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SiteInfoBean siteInfoBean = null; //文件信息Bean *[ ' n8Z  
long[] nStartPos; //开始位置 p#14  
long[] nEndPos; //结束位置 ~Te9Lq|  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 }Iyr u3M][  
long nFileLength; //文件长度 Z)V m,n
g  
boolean bFirst = true; //是否第一次取文件 rTJ='<hIy  
boolean bStop = false; //停止标志 OO7sj@  
File tmpFile; //文件下载的临时信息 ~Onj|w7  
DataOutputStream output; //输出到文件的输出流 Sf_q;Ws  
+&AKDVmx  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ?nVwT[  
public SiteFileFetch(SiteInfoBean bean) throws IOException iCz0T,  
{ nqp:nw  
siteInfoBean = bean; F'
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;f]p`!] 3  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); [H~Yg2O  
if(tmpFile.exists ()) q+j.
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{ ywSV4ZtM  
bFirst = false; ~RdD6V  
read_nPos(); *8QES
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} %1E
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else |iGfX,C|  
{ dwH8Zg$B  
nStartPos = new long[bean.getNSplitter()]; EnM }H9A  
nEndPos = new long[bean.getNSplitter()]; d65fkz==A)  
} 0XkLWl|k  
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} ]"ZL<?3g
 
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public void run() 0 |/:m  
{ JYAtQTOR  
//获得文件长度 r8R]0\  
//分割文件 MD"a%H#p  
//实例FileSplitterFetch U-U^N7  
//启动FileSplitterFetch线程 qD/GYqvm  
//等待子线程返回 g6s&nH`Z2  
try{ QU#u5sX A  
if(bFirst) !Q/%N#  
{ d`XC._%^J  
nFileLength = getFileSize(); ;^[VqFpeS  
if(nFileLength == -1) nnzfKn:J  
{ =XRTeIZ  
System.err.println("File Length is not known!"); #hKaH -j  
} N7wKaezE  
else if(nFileLength == -2) )s#NQ.T[  
{ 0mb|JoE(  
System.err.println("File is not access!"); ~o<+tL  
} /
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else `4xnM`:L"  
{ OI8Hf3d=  
for(int i=0;i<nStartPos.length;i++) UY ^d
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{ lc:dKGF6  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); }L!%^siG_  
} \*wQ%_N5  
for(int i=0;i<nEndPos.length-1;i++) !ek};~(  
{ u|.c?fW'3  
nEndPos = nStartPos[i+1]; eU*0;#  
} ^(Y}j8sj  
nEndPos[nEndPos.length-1] = nFileLength; V(?PKb-w)  
} OBCH%\;g  
} &rc]3! B  
9=l6NNe)|  
ORc20NFy7  
//启动子线程 wU"0@^k]<  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; }k{h^!fV  
for(int i=0;i<nStartPos.length;i++) o94]:$=~  
{ -&7\do<  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ycD}7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), y8HwyU>  
nStartPos,nEndPos,i); !{WIN%O  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f%g^6[  
fileSplitterFetch.start(); hoLQuh%2%  
} 8V08>M  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), dF`\ewRFn  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); m|CB')  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Li?_P5+a  
nEndPos = " + nFileLength); &az :YTq  
// fileSplitterFetch[nPos.length-1].start(); qH8d3?1XO  
+L]$M)*0&  
#^] v5s  
//等待子线程结束 b3vPGR  
//int count = 0; YVcO+~my  
//是否结束while循环 `pTCK9  
boolean breakWhile = false; NI%&Xhn!*>  
'g@Yra&09  
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while(!bStop) 6^Q/D7U;s  
{ wuV*!oefo  
write_nPos(); p$:ERI  
Utility.sleep(500); ov9+6'zya  
breakWhile = true; $Ith8p~  
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for(int i=0;i<nStartPos.length;i++) I\8F.J1_  
{ C 7a$>#%  
if(!fileSplitterFetch.bDownOver) c97?+Y^  
{ -,Oq=w*EV  
breakWhile = false; ;Pd nE~  
break; 7C::%OF~7  
} [dXpz^Co  
} BB.^[:,dA  
if(breakWhile) ~x #RIt  
break; gx55.}  
5L!cS+QNU  
+{5y,0R  
//count++; pVa9g)+z}  
//if(count>4) |u@/,x
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// siteStop(); ib,BYFKEW  
} T!F0_<  
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System.err.println("文件下载结束！"); P2t{il
 
} 6]D%|R,Q#}  
catch(Exception e){e.printStackTrace ();} yd>b2 M  
} \Aa{]t  

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er44s^$  
//获得文件长度 i*\\j1mf  
public long getFileSize() g)M"Cx.  
{ _=Eb:n+X  
int nFileLength = -1; D00v"yp%%  
try{ 9()d7Y#d/`  
URL url = new URL(siteInfoBean.getSSiteURL()); =mQdM]A)2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); YKV?I   
httpConnection.setRequestProperty("User-Agent","NetFox"); 7/>#yR  
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int responseCode=httpConnection.getResponseCode(); cmu|d  
if(responseCode>=400) H-g CY|W  
{ z=[?&X]O9b  
processErrorCode(responseCode); E8LZ% N#  
return -2; //-2 represent access is error tSf$`4  
} 4F=cER6l  
'&+5L.  
1.S?(1e"  
String sHeader; 5 >c,#*  
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for(int i=1;;i++) @GyxO
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{ (/;<K$u*h  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); (l_/ HQ32  
//Utility.log(in.readLine()); nb|KIW  
sHeader=httpConnection.getHeaderFieldKey(i); Py^fWQ5I~%  
if(sHeader!=null) 6!T9VL\=H  
{ R[v
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if(sHeader.equals("Content-Length")) uozK'L  
{ ,u@V
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); RqU^Q*/sF
 
break; U'oFW@Y;h  
} P ?A:0a  
} s.IYPH|pn  
else DV!10NqUr  
break; /73ANQ"  
} jV 982Y  
} Pu0 <Clh  
catch(IOException e){e.printStackTrace ();} 3bBCA9^se  
catch(Exception e){e.printStackTrace ();} f j:q>}V  
'i;/?'!W6  
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Utility.log(nFileLength); 4m"6$  
/3KPK4!m  
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return nFileLength; ;^f ;<  
} 8:gUo8  
{7Qj+e^  
Y9r##r+  
//保存下载信息（文件指针位置） 08MY=PC~R  
private void write_nPos() Q^}Ib[  
{ IY40d^x  
try{ ANuO(
^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); -PiakX  
output.writeInt(nStartPos.length); ,k |QuOrCh  
for(int i=0;i<nStartPos.length;i++) %/}46z9\  
{ "STd ;vR  
// output.writeLong(nPos); ,vcd>"PK  
output.writeLong(fileSplitterFetch.nStartPos); ~kp,;!^vr  
output.writeLong(fileSplitterFetch.nEndPos); ko+fJ&$  
} ?8-ho0f0  
output.close(); 8Xx4W^*_  
} H#:Aby-d}  
catch(IOException e){e.printStackTrace ();} G/N1[)  
catch(Exception e){e.printStackTrace ();} PdqyNn=  
} Y_= ]w1  
/I48jO^2  
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//读取保存的下载信息（文件指针位置） sIzy/W0iV  
private void read_nPos() B*OBXN>'P  
{ bR'UhPs-8;  
try{ XP^[,)E  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); r?2J 
 
int nCount = input.readInt(); #5yz~&  
nStartPos = new long[nCount]; ngOGo =
 
nEndPos = new long[nCount];
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for(int i=0;i<nStartPos.length;i++) C17$qdV/  
{ c|s7cG$+-  
nStartPos = input.readLong(); PrhGp _5  
nEndPos = input.readLong(); [=]LR9c4  
} LhC
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input.close(); :YCB23368"  
} E RjMe'q4  
catch(IOException e){e.printStackTrace ();} cnz+%Y N  
catch(Exception e){e.printStackTrace ();} S0w:R:q}L  
} +'9E4Lpx  
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private void processErrorCode(int nErrorCode) vLIaTr gz  
{ 9>r@wK'Pn  
System.err.println("Error Code : " + nErrorCode); a: 2ezxP  
} _6.Y3+7I  
|_mN:(3  
Pos(`ys;  
//停止文件下载
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public void siteStop() \49s;\I]  
{ B^@X1EE  
bStop = true; Xbu P_U'  
for(int i=0;i<nStartPos.length;i++) >Xi/ p$$7u  
fileSplitterFetch.splitterStop(); UsgrI>|l  
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} 3(`P x}  
} rGlnu.mK^  
//负责部分文件的抓取 k]rc -c-  
**FileSplitterFetch.java [Om,Q<
  
*/ a5?Yh<cJ  
package NetFox; a= (vS  
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import java.io.*; @a (-U.CZ  
import java.net.*; ldt]=Sqy  
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public class FileSplitterFetch extends Thread { Gq-~zmg  
NA+7ey6  
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String sURL; //File URL 5Z`f.}^w  
long nStartPos; //File Snippet Start Position H'}6Mw%ra  
long nEndPos; //File Snippet End Position U+,RP$r@  
int nThreadID; //Thread's ID ,olP}  
boolean bDownOver = false; //Downing is over [ d`m)MW-  
boolean bStop = false; //Stop identical -I[KIeF  
FileAccessI fileAccessI = null; //File Access interface NqM=Nu\  
"V`5 $ur  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException v8K`cijSS  
{ -z">ov-)  
this.sURL = sURL; V1yP{XT=  
this.nStartPos = nStart; <"yL(s^u"  
this.nEndPos = nEnd; .'b|pd  
nThreadID = id; JnLF61   
fileAccessI = new FileAccessI(sName,nStartPos);//定位 o~M=o:^nH  
} ajW2HH*9}A  
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public void run() .Nk5W%7]=  
{ 1Gy [^  
while(nStartPos < nEndPos && !bStop) B Q2N_*v  
{ P=.~LZZ]89  
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VniU:A  
try{ mrBK{@n  
URL url = new URL(sURL); )Em`kle  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); u.Tknw-X  
httpConnection.setRequestProperty("User-Agent","NetFox"); s8dP=_ `  
String sProperty = "bytes="+nStartPos+"-"; Z1_F)5
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httpConnection.setRequestProperty("RANGE",sProperty); Dt\rrN:v  
Utility.log(sProperty); beB3*o  
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InputStream input = httpConnection.getInputStream(); }Fsr"RER@{  
//logResponseHead(httpConnection); T+oOlug  
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byte[] b = new byte[1024]; l{*Ko~g  
int nRead; _*Ej3=u  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) tX6_n%/L  
{ n=?wX#rEC#  
nStartPos += fileAccessI.write(b,0,nRead); *fz#B/_o  
//if(nThreadID == 1) |g'ceG-  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3H|drj:KV  
} R_b4S%jhx  
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Utility.log("Thread " + nThreadID + " is over!"); c Qe3  
bDownOver = true; A4(k<<xjE  
//nPos = fileAccessI.write (b,0,nRead); w c  
} b,X+*hRt  
catch(Exception e){e.printStackTrace ();} \VWgF)_  
} p`EgMzVO,  
} Z5 7.+z<  
~n!&~  
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//打印回应的头信息 >!Xj%RW  
public void logResponseHead(HttpURLConnection con) _-rC]iQJ55  
{ DF UTQ:N  
for(int i=1;;i++) ;y-:)7J  
{ j{D tjV8  
String header=con.getHeaderFieldKey(i); &xZSM,  
if(header!=null) )+ 'r-AF*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 7 IJn
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Utility.log(header+" : "+con.getHeaderField(header)); +d7Arg!m  
else aKE`nA0\B  
break; UD.ZnE{"  
} 5nTcd
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} CM%;/[WBxy  
!cdY`f6x  
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public void splitterStop() |6;-P&_n  
{ ||ugb6q[6B  
bStop = true; eiXl"R^  
} :@a0h
  
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={f8s,m)P,  
} |3 Iug  
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]
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/* R.DUfU"gp  
**FileAccess.java S^
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*//文件访问(定位，写) *?$M=tH  
package NetFox; n`@dk_%yI  
import java.io.*; &SNH1b#>E  
sT "q]  
}!?RB v'W  
public class FileAccessI implements Serializable{ wX_~H*m?  
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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 9|[uie  
RandomAccessFile oSavedFile; :H&G}T
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long nPos; a>rDJw:  
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public FileAccessI() throws IOException E m^Dg9  
{ hgzNEx%^q  
this("",0); qozvNJm)  
} y. 1F@w|  
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public FileAccessI(String sName,long nPos) throws IOException NUJ $)qNA  
{ ly35n`  
oSavedFile = new RandomAccessFile(sName,"rw"); aC%Q.+-t  
this.nPos = nPos; Jgg<u#  
oSavedFile.seek(nPos); l5~O}`gfh  
} mlCg&fnDB  
1
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public synchronized int write(byte[] b,int nStart,int nLen) (9kR'kr  
{ WUo\jm[yr  
int n = -1; `34{/}w  
try{ /HS"{@Z"h  
oSavedFile.write(b,nStart,nLen); 0FY-e~xr  
n = nLen; &%GAPs%  
} iK+Vla`}  
catch(IOException e) Jp%5qBS^
 
{ 8UXRM :Z"  
e.printStackTrace (); M_-L#FHX  
} ipl,{  
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return n; (x?Tjyzw  
} 9thG4T8  
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} kU=U u>  
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2
  
/* A<"<DDy  
**SiteInfoBean.java GBWL0'COV  
*/ UV0[S8A  
package NetFox; ,|}mo+rb-  
V=% ;5/  
__
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public class SiteInfoBean { Wz"H.hf  
-zn_d]NV  
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private String sSiteURL; //Site's URL _H@ATut  
private String sFilePath; //Saved File's Path Hk@Gkx_  
private String sFileName; //Saved File's Name K
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private int nSplitter; //Count of Splited Downloading File ciiI{T[Z  
'21gUYm  
)wCNLi>4
 
public SiteInfoBean() T_=WX_h $  
{//nSplitter的缺省值为5 g}W|q"l?i  
//default value of nSplitter is 5 ;b~\[  
this("","","",5); 3)6-S  
} FMI1[|:;  
lw[c+F7  
1^E5VG1[  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {jmy:e2  
{ 3l41"5Fy&  
sSiteURL= sURL; GGr82)E  
sFilePath = sPath; 2 \}J*0  
sFileName = sName; %lWOW2~R  
this.nSplitter = nSpiltter; # Q,EL73;  
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} R3l{.{3p2  
zxCx
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public String getSSiteURL() 3\Q9>>  
{ /e?0Iv" 8>  
return sSiteURL; dt,Z^z+"E  
} ~IjID
 
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5Gy#$'kdf  
public void setSSiteURL(String value) "t(_r@qU/  
{ f$:SacF  
sSiteURL = value; DyiJ4m}kh  
} X!^|Tass  
9J?s:"j  
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public String getSFilePath() xk% 62W  
{ 25-h5$s  
return sFilePath; megTp  
} AH5;6Q  
htR.p7&Tn  
p/VVb%  
public void setSFilePath(String value) u;-fG9xs  
{ xlu4  
sFilePath = value; n+hL/aQ+  
} \|HNFxT`  
.6a
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<?5|(Q"@:  
public String getSFileName() C-;w}  
{ uW[[8+t|  
return sFileName; Cp"7
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} z|D*ymz*EY  
U4\v~n\  
4d4+%5GE  
public void setSFileName(String value) ]2qKc  
{ M?%x=q\<  
sFileName = value; 9g5h~Ma  
} = a60Xv  
-[ gT}{k!  
BDWbWA 6  
public int getNSplitter() 'u;O2$  
{ _3yG<'f[Y  
return nSplitter; Z9+fTT  
} H4AT>}ri  
tLa%8@;'$  
|oXd4  
public void setNSplitter(int nCount) v#/Gxk9eX  
{ 62qjU<Z
 
nSplitter = nCount; )j>U4a  
} ;VAyH('~  
} 79W^;
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8Ejb
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/* "^\q{S&q2P  
**Utility.java s) shq3O  
*/ dM^Z,;u  
package NetFox; #Ir?v  
0O>ClE~P  
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public class Utility { Q'jw=w!|g  
ikV;]ox  
mL48L57Z  
public Utility()  Q}L?o  
{ yW=+6@A4  
C$1W+(  
\>- M&C  
} jTcv&`fAz  
7<] EH:9  
//线程睡眠 p|ink):  
public static void sleep(int nSecond) Pa{  
{ f(Of+>   
try{ '1gfXC  
Thread.sleep(nSecond); R/ZScOW[  
} Pp tuXq%U  
catch(Exception e) Jq'8"  
{ _o$jk8jOjW  
e.printStackTrace (); ~! -JN}H m  
} ~$g:  
} BA]$Fi.Mw  
,dCEy+  
//日志 bT^dtEr[  
public static void log(String sMsg) WqCC4R,-  
{ QH9t |l  
System.err.println(sMsg); l\*9rs:!  
} @5S'5)4pB  
Q7$o&N{  
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0b
 
public static void log(int sMsg) .PUp3X-  
{ !{t|z=Qg  
System.err.println(sMsg); #;j:;LRU  
} WI/tWj0  
} Ec@n<KK#  
2+ cs^M3  
Szgo@x$^  
/* wwB3m&  
**TestMethod.java Lz'VQO1U=  
*/ RDp  
package NetFox; akzGJ3g  
4\Y5RfLB_  
0+*NHiH  
public class TestMethod { pi?MAE*f  
GT&}Burl/n  
-SrZ^  
public TestMethod() F^75y?  
{ ///xx/weblogic60b2_win.exe 0 Uropam  
try{ o3fc-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #_wq#rF  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); KkA)p/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 9qB0F_xl  
fileFetch.start(); q*l4h u%3  
} tg/UtE`V  
catch(Exception e){e.printStackTrace ();} TJO$r6&  
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U%nkPIFm  
} <h7cQ  
,RV qYh(-|  
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public static void main(String[] args) Cku"vVw,  
{ bP&QFc  
new TestMethod(); ixdsz\<  
} 0Ds3wNz  
}
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