http断点续传简单实现（java)

/* 4\Q pS  
**SiteFileFetch.java 7[I%UP  
*/ '$0~PH&  
package NetFox; w D}g\{P  
import java.io.*; /idrbc  
import java.net.*; *Dhy a g  
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public class SiteFileFetch extends Thread { o;"Phc.  
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SiteInfoBean siteInfoBean = null; //文件信息Bean V;IV2HT0J"  
long[] nStartPos; //开始位置 ;oM7H*WC  
long[] nEndPos; //结束位置 @%b
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 TbQ5  
long nFileLength; //文件长度 Y;"rJxHD  
boolean bFirst = true; //是否第一次取文件 @b3jO  
boolean bStop = false; //停止标志 cii
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File tmpFile; //文件下载的临时信息 5fvY#6;  
DataOutputStream output; //输出到文件的输出流 iXPe  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） <|>7?#s2=  
public SiteFileFetch(SiteInfoBean bean) throws IOException p:Hg>Z  
{ 9#MY(Hr  
siteInfoBean = bean; -d)+G%{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); p0sq{d~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); o>jM4sk$  
if(tmpFile.exists ()) Ad)::9K?J  
{ 6k
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bFirst = false; WlHK  
read_nPos(); X:kr$  
} &|YJ?},  
else Bm$(4  
{ _^MkC}8  
nStartPos = new long[bean.getNSplitter()]; FQe82tfV+  
nEndPos = new long[bean.getNSplitter()]; ;6655C  
} ~cH3RFV  
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} J e"~/+  
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public void run() (T|q]29  
{ COc t d  
//获得文件长度 GyQ9we~  
//分割文件 ~5]%+
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//实例FileSplitterFetch .8dlf7* ,  
//启动FileSplitterFetch线程 "pMx(  
//等待子线程返回 hF^y4v|5  
try{ 13aj fH  
if(bFirst) LQz6o
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{ fWs@ZCt  
nFileLength = getFileSize(); 'Da*MGu9  
if(nFileLength == -1) w#^z:7fI  
{ 2>*b.$g  
System.err.println("File Length is not known!"); |))O3]-  
} 9D[Jn}E:  
else if(nFileLength == -2) /8Ru
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{ 0BrAgv"3a_  
System.err.println("File is not access!"); $_f"NE}  
} .I%`yhCW  
else NbPNcjPL  
{ jz$ ]"\G#  
for(int i=0;i<nStartPos.length;i++) ;!(GwgllD  
{ 9/#
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); Xy]Pmt  
} yvIzgwN%s!  
for(int i=0;i<nEndPos.length-1;i++) T)o>U&KNP  
{ ]114\JE  
nEndPos = nStartPos[i+1]; !g7lJ\
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} 1LVO0lT  
nEndPos[nEndPos.length-1] = nFileLength; zff<#yK1  
} QWI)Y:<K/  
} s"JD,gm$  
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//启动子线程 d#1yVdqR
l  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; SIZZFihcYh  
for(int i=0;i<nStartPos.length;i++) Fk#$@^c@  
{ YR-G
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >/.w80<'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #?C.%kD  
nStartPos,nEndPos,i); 2y5d  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mX5%6{],  
fileSplitterFetch.start(); ;~-M$a }4  
} B+2EIaI  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @hw
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); sR;u#".  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Xv<K>i>k  
nEndPos = " + nFileLength); |*(
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// fileSplitterFetch[nPos.length-1].start(); MqjdW   
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//等待子线程结束 {Jc.49  
//int count = 0; Om_-#S  
//是否结束while循环 ;<l#k7/  
boolean breakWhile = false; > JV$EY,  
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while(!bStop) 2rxz<ck(  
{  &4{!5r  
write_nPos(); ~@$RX:p  
Utility.sleep(500); K$KVm^`  
breakWhile = true; lWakyCS  
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|8?DQhd}  
for(int i=0;i<nStartPos.length;i++) x|$|~6f=n  
{ 4n} a%ocv^  
if(!fileSplitterFetch.bDownOver) tID=I0D  
{ "\+.S]~  
breakWhile = false; 6d(D>a  
break; I8f='  
} C`=YGyj=TL  
} 2(U;{;\n*  
if(breakWhile) ^*"i *e  
break; >%H(0G#X  
2b K1.BD  
[\e/xY(4  
//count++; JbAmud,  
//if(count>4) SQDfDrYP  
// siteStop(); H/y,}z  
} y96HTQ32  
\Oxyc}&  
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System.err.println("文件下载结束！"); X?U'GLm  
} yA#nnu1  
catch(Exception e){e.printStackTrace ();} 8a3EVc  
} C6'K)P[p  
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o Vpq*"  
//获得文件长度 qTSe_Re  
public long getFileSize() Lp)P7Yt-  
{ 66-tNy  
int nFileLength = -1; `|2g&Vn  
try{ 14DhJUV"b  
URL url = new URL(siteInfoBean.getSSiteURL()); 8Si3 aq3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2ck0k,WP  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ab6R?mUM  
2ZEDyQM  
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int responseCode=httpConnection.getResponseCode(); [1nUq!uTm  
if(responseCode>=400) Mc&Fj1h5  
{ J7Mbv2
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processErrorCode(responseCode); ey6ujV7!  
return -2; //-2 represent access is error Zs4NN2~  
} ?a-5^{{  
k [LV^oEg  
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String sHeader; &["e1ki  
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for(int i=1;;i++) {isL<  
{ 2u$r
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); _F5*\tQ  
//Utility.log(in.readLine()); ( k,?)  
sHeader=httpConnection.getHeaderFieldKey(i); zdm2`D;~p  
if(sHeader!=null) pzZ+!d  
{ =*R6O,  
if(sHeader.equals("Content-Length")) _+.JTk  
{ q~^!Ck+#*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [{`2FR:Cd  
break; Q'Tg0,,S  
} \ef:H&r  
} ^HxIy;EQ<z  
else I1Otu~%d  
break; yfal'DqKF  
} *E]:VZl  
} SsPZva  
catch(IOException e){e.printStackTrace ();} 9F[_xe@  
catch(Exception e){e.printStackTrace ();} _M+7)[xj=  
s94*uZ(C/  
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Utility.log(nFileLength); ia(`3r  
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return nFileLength; f>bL }L  
} A'.=SA2.Y  
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'/)qI.  
//保存下载信息（文件指针位置） e^'|<0J  
private void write_nPos() i\O^s ]  
{ )*`h)`\y  
try{ ":f]egq -  
output = new DataOutputStream(new FileOutputStream(tmpFile)); S+#|j  
output.writeInt(nStartPos.length); |#s
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for(int i=0;i<nStartPos.length;i++) (k8}9[3G  
{ +H28F_#  
// output.writeLong(nPos); KK6n"&TVa  
output.writeLong(fileSplitterFetch.nStartPos); wSw> UU  
output.writeLong(fileSplitterFetch.nEndPos); 6']HmM  
} )XHn.>]nc  
output.close(); U E$Ix  
} XMiu}w!  
catch(IOException e){e.printStackTrace ();} lB0`|UEb (  
catch(Exception e){e.printStackTrace ();} y/5GY,z%aL  
} Rw|'LaW  
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x|O^#X(,  
//读取保存的下载信息（文件指针位置） NSBcYObX  
private void read_nPos() %pxO<O  
{ *\(z"B  
try{ * k<@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {0j_.XZ  
int nCount = input.readInt(); AL.psw-Il  
nStartPos = new long[nCount]; !=A;?Kdq  
nEndPos = new long[nCount]; IrMB=pWo  
for(int i=0;i<nStartPos.length;i++) i")0 3b  
{ 8XG';K_  
nStartPos = input.readLong(); .r2*tB).  
nEndPos = input.readLong(); Q@7d:v  
} Bp3E)l  
input.close(); <N1wET-  
} B]@25  
catch(IOException e){e.printStackTrace ();} 
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catch(Exception e){e.printStackTrace ();} XbqMWQN*  
} ]8}51y8  
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private void processErrorCode(int nErrorCode) u*TC
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{ B\v+C!/f|  
System.err.println("Error Code : " + nErrorCode); Xl$,f`f~  
} 993f6  
:aK?DtZ  
:8!RGtn  
//停止文件下载 5nUJ9sqA  
public void siteStop() Ml7 (<J  
{ BHf$ %?3z,  
bStop = true; d&[RfZ`  
for(int i=0;i<nStartPos.length;i++) ]%)<9]}  
fileSplitterFetch.splitterStop(); Qr9;CVW  
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} ,/D}a3JD  
} Z*q9vX  
//负责部分文件的抓取 xEp?|Q$  
**FileSplitterFetch.java Dlq!:dF{&  
*/ KWZhCS?[(  
package NetFox; Zym6btc  
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import java.io.*; IQRuqp KL  
import java.net.*; >m>F {v  
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public class FileSplitterFetch extends Thread { NS~;{d\  
^>?=L\[  
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String sURL; //File URL <;6{R#Tuh  
long nStartPos; //File Snippet Start Position iCE!TmDT  
long nEndPos; //File Snippet End Position ,|{`(y/v  
int nThreadID; //Thread's ID MQQm3VaKS  
boolean bDownOver = false; //Downing is over mK[Z#obc=  
boolean bStop = false; //Stop identical Wn'a'  
FileAccessI fileAccessI = null; //File Access interface bI55G#1G  
A^>@6d $2  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException G aV&y  
{ P[2!D)A  
this.sURL = sURL; wSN9`"  
this.nStartPos = nStart; x,!Dd  
this.nEndPos = nEnd; 4|=>gdW)KN  
nThreadID = id; c Mgd  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #$I@V4O;#  
} ^$K&Met  
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public void run() #i[:oC6m:  
{ m&:&z7^p  
while(nStartPos < nEndPos && !bStop) Aqmpo3P[+  
{ "bm|p/A  
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try{ >fH0>W+!  
URL url = new URL(sURL); Y%XF64)6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wq$$. .E  
httpConnection.setRequestProperty("User-Agent","NetFox"); EtKq.<SJ  
String sProperty = "bytes="+nStartPos+"-"; K(EJ`2]:r  
httpConnection.setRequestProperty("RANGE",sProperty); %MeAa?G-#  
Utility.log(sProperty); #ibwD:{  
2:*15RH3  
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InputStream input = httpConnection.getInputStream(); =AIFu\9#a`  
//logResponseHead(httpConnection); 'D+xs}\  
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'J,UKK\5  
byte[] b = new byte[1024]; (S~kyU!)0  
int nRead; ?zW'Hi  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) FDMQLxf  
{ * Gg7(cnpw  
nStartPos += fileAccessI.write(b,0,nRead); rNP;53FtZl  
//if(nThreadID == 1) B\J[O5},
 
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6}^x#9\  
} T}&A-V$  
>C0B!MT?3%  
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Utility.log("Thread " + nThreadID + " is over!"); kR<sSLEb  
bDownOver = true; aTvyzr1  
//nPos = fileAccessI.write (b,0,nRead); LT%~C
uf  
} `<YMkp[  
catch(Exception e){e.printStackTrace ();} 7{#p'.nc5  
} qs]W2{-4~  
} >z<L60S  
ug9Ja)1|  
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//打印回应的头信息 A;co1,]gR  
public void logResponseHead(HttpURLConnection con) 56pj(}eq  
{ )G2Bx+Z;L  
for(int i=1;;i++) ygz2bHpD~  
{ {!I`EN]  
String header=con.getHeaderFieldKey(i); ?NoNg^Of  
if(header!=null) jJ2rfdfj  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); RuHDAJ"&a  
Utility.log(header+" : "+con.getHeaderField(header)); JI@iT6.%IX  
else #un'?]tZF  
break; Ftyxz&-4$p  
} [vu;B4^"  
} WL+EpNKSf  
#VhdYDbW  
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public void splitterStop() (Aw@}!  
{ o6u^hG6~'  
bStop = true; fHaF9o+/b  
} 27Gff(  
t ]BG)]  
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} Y$OE[nGi%X  
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/* MgiW9@_(  
**FileAccess.java 1#Vd)vSP  
*//文件访问(定位，写) +`flIG3RV  
package NetFox; 4l0>['K&{  
import java.io.*; 24od74\  
U/Cc!WXV]  
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public class FileAccessI implements Serializable{ 5xc e1[  
TTO8tT3[6}  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @CM5e!  
RandomAccessFile oSavedFile; 7jw+o*;  
long nPos; <mJ8~  
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public FileAccessI() throws IOException rrC\4#H[??  
{ |

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this("",0); sC"w{_D@*4  
} n:a~=^IV  
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public FileAccessI(String sName,long nPos) throws IOException 5ms]Wbh)  
{ n+ H2cl }  
oSavedFile = new RandomAccessFile(sName,"rw"); |A68+(3u  
this.nPos = nPos; T: My3&6  
oSavedFile.seek(nPos); SP<(24zdd  
} +b_[JP2  
p! k~ufU  
~zZOogM<  
public synchronized int write(byte[] b,int nStart,int nLen) }x#e.}hf&  
{ $J<WFDn9  
int n = -1; le_aIbB"P  
try{ 'Jek< 5  
oSavedFile.write(b,nStart,nLen); y<HNAGj  
n = nLen; -F(luRBS(W  
} X!{K`~DRX  
catch(IOException e) e1b?TF@lz  
{ $[Ut])4 ~  
e.printStackTrace (); %*K zP{  
} xVYa-I[Z  
G]$EIf'  
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return n; :
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} h=6D=6c  
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}l}_'FmQ  
} BK)<~I  
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J8@.qC'!  
/* 7}MnvWP  
**SiteInfoBean.java
' -9=>  
*/ _Wk*h}x  
package NetFox; LPs5LE[Pm  
*:+ZEFMq  
Y^DGnx("m  
public class SiteInfoBean { vgDpo@fz8  
>hSu1s:  
rtbV*@Z  
private String sSiteURL; //Site's URL .x] pJ9  
private String sFilePath; //Saved File's Path -{C Gn5]_#  
private String sFileName; //Saved File's Name [n&ES\o#(  
private int nSplitter; //Count of Splited Downloading File o%`=+-K  
z Fj|E  
ZNDi;6e  
public SiteInfoBean() 5}_=q;sZ  
{//nSplitter的缺省值为5 <}'=@a  
//default value of nSplitter is 5 79}jK"Gc  
this("","","",5); Bxw(pACf  
} oP4+:r)LKD  
 /d!  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) hosY`"X  
{ %,<Ki]F  
sSiteURL= sURL; Nmt~1
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sFilePath = sPath; %\|{_]h}y  
sFileName = sName; vGPsjxk&  
this.nSplitter = nSpiltter; QS\wtTXj  
a]%sks
 
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} q &{<HcP  
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public String getSSiteURL() %yjD<2J;  
{ (dQ=i  
return sSiteURL; aHYISjZ]>  
} 1kUlQ*[<|  
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public void setSSiteURL(String value) Suo$
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{ dVHbIx  
sSiteURL = value; Yc_(g0NK  
} "8cI]~V  
[2Nux0g  
~7*2Jp'  
public String getSFilePath() :lvBcFw  
{ m_Q&zp["  
return sFilePath; =8<~pr-NO  
} (*Q:'2e  
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3/Z>W|w#w  
public void setSFilePath(String value) ]PoWL;E'  
{ 8=joVbs  
sFilePath = value; v0E6i!D/  
} m9i/rK_  
\#B<'J9.`  
7C3YVm6g  
public String getSFileName() w( XZSE  
{ fHH  
return sFileName; 0('ec60u  
} >-<iY4|[d  
/"j3B\`?  
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public void setSFileName(String value) pe+h8  
{ y*-_  
sFileName = value; rZaO^}u]  
} b"N!#&O
]  
<"P-7/j3j  
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public int getNSplitter() DmLx"%H3  
{ hp9U   
return nSplitter; C
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} ]6)u$4X6$  
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^  
!@8i(!xb  
public void setNSplitter(int nCount) x6s|al  
{ LjG^c>[:m  
nSplitter = nCount; 5Q"w{ n  
} f6`GU$H  
} :\His{%  
er)I".|  
:Q3pP"H,}  
/* x}?<9(nE c  
**Utility.java Hn(1_I%zF  
*/ wAprksZL#  
package NetFox; &.*UVc2+Y  
#H>{>0q  
^Q$OzsEk  
public class Utility { =ZIT!B?4  
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public Utility() gK[;"R)4o@  
{ iT4*~(p 3  
6- i.*!I 8  
cA q3Gh  
} ,=m.WmXE  
hb5K"9Y  
//线程睡眠 k*hl"oL"X  
public static void sleep(int nSecond) @9gZH_ur>E  
{
"[|b,fxR  
try{ U@mznf* J  
Thread.sleep(nSecond); ]19VEH  
} +&`W\?.~  
catch(Exception e) \%=\4%:  
{ <'
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e.printStackTrace (); x.?5-3|d$  
} |HAJDhM,l  
} 'kZ,:.v  
{ :tO RF  
//日志 ^hC'\09=c  
public static void log(String sMsg) YZBh}l6t  
{ ((k"*f2%  
System.err.println(sMsg); LmF,en5  
} ]yU"J:/  
v~P,OP("c  
q!5:M\  
public static void log(int sMsg) _95296  
{ yp.K-  
System.err.println(sMsg); Wp=3heCa6  
} Nz,yd%ua  
} u]J@
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/* p~qe/  
**TestMethod.java L[G O6l  
*/ N4!`iS Y  
package NetFox; C9n%!()>  
%a;#]d  
y/lF1{}5  
public class TestMethod { *U?O4E9  
:gh[BeqQ)  
#<im?  
public TestMethod() "ZuuSi  
{ ///xx/weblogic60b2_win.exe qLN^9PdEE  
try{ n+~Dc[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =!O->C:  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); T~TP  
SiteFileFetch fileFetch = new SiteFileFetch(bean); #%0V`BS7n  
fileFetch.start(); `2s!%
/  
} rl*O-S/  
catch(Exception e){e.printStackTrace ();} Mqf Ns<2  
~GaGDS\V  
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} bLgH3[{  
K2x[ApS#  
p*Bty@CRi  
public static void main(String[] args) [4Z 31v>  
{ 24mdhT|  
new TestMethod(); @ D+ft
b/  
} 2ej7Ql_@c  
} (!os&/",  
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