http断点续传简单实现（java)

/* fkE4[X7f  
**SiteFileFetch.java #mg6F$E  
*/ >I
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package NetFox; gQaBQq9  
import java.io.*; c:
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import java.net.*; nIdB,  
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public class SiteFileFetch extends Thread { K3*8JF7_F  
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SiteInfoBean siteInfoBean = null; //文件信息Bean BwtjTwd  
long[] nStartPos; //开始位置 8 tMfh  
long[] nEndPos; //结束位置 !4-B xeNY\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 1A\Jh3;Q  
long nFileLength; //文件长度 T0BFit6  
boolean bFirst = true; //是否第一次取文件 rlG&wX  
boolean bStop = false; //停止标志 ol]"r5#Q_H  
File tmpFile; //文件下载的临时信息 S^nshQI  
DataOutputStream output; //输出到文件的输出流 ,E,oz{,i(  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） I;iJa@HWQ  
public SiteFileFetch(SiteInfoBean bean) throws IOException :*
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{ gyi<ot;  
siteInfoBean = bean; _kUf[&  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); sYnf #'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");
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if(tmpFile.exists ()) F<SMU4]YdG  
{ 2qV.`d  
bFirst = false; >7%Gd-;l  
read_nPos(); F FHk0
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} MT
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else d]Y-^&]{]  
{ N&g9z{m7  
nStartPos = new long[bean.getNSplitter()]; mFCDwh]  
nEndPos = new long[bean.getNSplitter()]; E
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} 1haH2F^q3  
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} r #H(kJu,  
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public void run() %|mRib|<C  
{ pzcV[E1  
//获得文件长度 QC@nRy8%  
//分割文件 -={Z::}S"  
//实例FileSplitterFetch N"-</kzV  
//启动FileSplitterFetch线程 xXG-yh  
//等待子线程返回 E?%SOU<  
try{ 5!
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if(bFirst) p H&Tb4  
{ 4o7(cP  
nFileLength = getFileSize(); TAfLC)  
if(nFileLength == -1) >y&Db  
{ gG"W~O)yv  
System.err.println("File Length is not known!"); E.*TJ  
} >E*j4gg  
else if(nFileLength == -2) TI '(  
{ E"LSM]^^<f  
System.err.println("File is not access!"); jSMvZJX3n  
} 8@`"ZzM  
else so[i"ZM)  
{ bb<qnB  
for(int i=0;i<nStartPos.length;i++) m1,?rqeb  
{ [UO?L2$&  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5I#L|+  
} fq*.4s #  
for(int i=0;i<nEndPos.length-1;i++) l :sZ  
{ Q-<,+[/  
nEndPos = nStartPos[i+1]; w74)kIi  
} {Rc!S? 8  
nEndPos[nEndPos.length-1] = nFileLength; AhjK*nJF  
}
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} q ld2<W  
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//启动子线程 c
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; `-)!4oJ]  
for(int i=0;i<nStartPos.length;i++) V6)e Jy  
{ kpc3l[.A  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Af8&PhyrU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), wc#+Yh
6  
nStartPos,nEndPos,i); 7:fC,2+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~G0\57;h  
fileSplitterFetch.start(); ?m&?BsW$)  
} H|a9}
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1.7tXjRd+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 'FB?#C%U  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", *=]hc@  
nEndPos = " + nFileLength); {XC1B  
// fileSplitterFetch[nPos.length-1].start(); U`gQ7
 
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//等待子线程结束 d*
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//int count = 0; ~*-(_<FH  
//是否结束while循环 < C54cO  
boolean breakWhile = false; XA8{
N  
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9qIdwDRY  
while(!bStop) fhx_v^<X  
{ 4k9O6  
write_nPos(); YGp8./ma<I  
Utility.sleep(500); r^3QDoy  
breakWhile = true; "9=F/o9  
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Ap}^6_YXd  
for(int i=0;i<nStartPos.length;i++) ka_]s:>+  
{ m.ib#Y)y  
if(!fileSplitterFetch.bDownOver) _M n7zt1^  
{ u&)+~X  
breakWhile = false; rUC@Bf  
break; FJ}RT*7_C  
} `<I+(8]Uz  
} B+:'Ld](  
if(breakWhile) /[f9Z:>V  
break; _c*0Rr  
?yKW^,q+  
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//count++; N?`-$C ]  
//if(count>4) fp^!?u  
// siteStop(); ;B[*f?y-  
} B%HG7  
3OUZR5_$  
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System.err.println("文件下载结束！"); V+7x_>!&)  
} VEAf,{)Q  
catch(Exception e){e.printStackTrace ();} 96fzSZS,  
} #DMt<1#:  
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bYT,f.,5{  
//获得文件长度 NFT&\6
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public long getFileSize() -h&AO\*^W  
{ h WvQh  
int nFileLength = -1; (8C ,"Dc[0  
try{ <uXZ*E  
URL url = new URL(siteInfoBean.getSSiteURL()); [d="94Ab  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <uUHr,#  
httpConnection.setRequestProperty("User-Agent","NetFox"); H+&c=~D\_  
. IBy'  
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int responseCode=httpConnection.getResponseCode(); 3DH} YAUU  
if(responseCode>=400) O)g\/uRy  
{ RJ/4T#b"+  
processErrorCode(responseCode); h$`P|#V&  
return -2; //-2 represent access is error s)HLFdis@  
} rt+%&%wt  
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String sHeader; $[5S M>e]  
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29
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for(int i=1;;i++) (=n{LMa  
{ 2l5>>yY  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ,Y|WSKY*  
//Utility.log(in.readLine()); QXTl'.SfF  
sHeader=httpConnection.getHeaderFieldKey(i);
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if(sHeader!=null) V=%j]`Os  
{ 6?an._ C  
if(sHeader.equals("Content-Length")) #*QnO\.  
{ NRU&GCVwu  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [=dK%7v  
break; 9r,)Bw!RP  
} L4bx [  
} e nsou!l  
else CmyCne   
break; 
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} y\M]\^[7  
} DEj6 ky  
catch(IOException e){e.printStackTrace ();} i,5mH$a&u:  
catch(Exception e){e.printStackTrace ();} '6Lw<#It  
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Utility.log(nFileLength); p%;n4*b2  
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return nFileLength; oC"1{ybyl  
} 'Em5AA`>  
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rVo0H.+N)`  
//保存下载信息（文件指针位置） H{Fww4pn  
private void write_nPos() K"lZwU\:On  
{ $9LI v  
try{ "Dr8}g:X  
output = new DataOutputStream(new FileOutputStream(tmpFile)); W!@*3U]2R  
output.writeInt(nStartPos.length); L[M`LZpJo  
for(int i=0;i<nStartPos.length;i++) }@R*U0*E  
{ 9fLxp$`(T  
// output.writeLong(nPos); z=YHRS  
output.writeLong(fileSplitterFetch.nStartPos); $CT2E  
output.writeLong(fileSplitterFetch.nEndPos); /r
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} AXK
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output.close(); y2nwDw(xF  
} IEbk_-h[  
catch(IOException e){e.printStackTrace ();} puE!7:X7  
catch(Exception e){e.printStackTrace ();} nQy%av$  
} QzV Q}  
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//读取保存的下载信息（文件指针位置） =
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private void read_nPos() 2h:*lV^  
{ Vifh`BSP  
try{ S.^/Cl;aj  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); j>D[iHrH  
int nCount = input.readInt(); gHLvzm  
nStartPos = new long[nCount]; )HaW# ,XB  
nEndPos = new long[nCount]; ~Vh< mt  
for(int i=0;i<nStartPos.length;i++) 'aLTiF+  
{ ^p@ #  
nStartPos = input.readLong(); 57nSyd]PR  
nEndPos = input.readLong(); (fSpY\JPI  
} .=I:cniw\r  
input.close(); 71)DLGL  
} AEUXdMo  
catch(IOException e){e.printStackTrace ();} 5!tiu4LU  
catch(Exception e){e.printStackTrace ();} -chk\75  
} p`oSI}ZwB  
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private void processErrorCode(int nErrorCode) RxeyMNd  
{ J
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System.err.println("Error Code : " + nErrorCode); PPj_
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} p|q}z/  
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pb`!_GmB  
//停止文件下载 f&ZFG>)6  
public void siteStop() Oo-%;l`&  
{ 7ThGF  
bStop = true; cz{5-;$9Z  
for(int i=0;i<nStartPos.length;i++) [H-r0Ah  
fileSplitterFetch.splitterStop(); h#EksX  
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} O /S:S  
} :<"b"{X"  
//负责部分文件的抓取 x{|`q9V~ N  
**FileSplitterFetch.java vc r5  
*/ M@TXzn!&o  
package NetFox; S*0P[R  
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import java.io.*; "{1SDbwmMo  
import java.net.*; S8S<>W  
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public class FileSplitterFetch extends Thread { ^y1P~4w?  
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String sURL; //File URL [0lu&ak[&
 
long nStartPos; //File Snippet Start Position z}gfH|  
long nEndPos; //File Snippet End Position )9PP3"I  
int nThreadID; //Thread's ID r/G6O  
boolean bDownOver = false; //Downing is over p,cw-lN  
boolean bStop = false; //Stop identical }BR@vY'd  
FileAccessI fileAccessI = null; //File Access interface |cBeyqr  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException i^O(JC  
{ (mvzGXNz4  
this.sURL = sURL; P p]Ygt'u  
this.nStartPos = nStart; doj$chy  
this.nEndPos = nEnd; .&Q'aOg  
nThreadID = id; _$f XK  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {,Py%.vvR  
} >&`S$1 o  
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public void run() 7^3a296  
{ tt%lDr1A)  
while(nStartPos < nEndPos && !bStop) a-9Y &#U  
{ 2rG;j52))a  
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try{ 4|EV`t}EV  
URL url = new URL(sURL); "T?hIX/p_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Vw P+tM  
httpConnection.setRequestProperty("User-Agent","NetFox"); qa!3lb_'M  
String sProperty = "bytes="+nStartPos+"-";  HuCzXl  
httpConnection.setRequestProperty("RANGE",sProperty); P_:~!+W,  
Utility.log(sProperty); O:hCUr  
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InputStream input = httpConnection.getInputStream(); EU0b>2n4  
//logResponseHead(httpConnection); 7E}.P1  
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byte[] b = new byte[1024]; Y#A0ud,  
int nRead; ;hcOD4or  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) o2J-&   
{ ='p&T
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nStartPos += fileAccessI.write(b,0,nRead); At?]FjL6S  
//if(nThreadID == 1) FK2* O  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^#Ruw?D  
} gFx2\QV  
R54wNm@  
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Utility.log("Thread " + nThreadID + " is over!"); /%P|<[< [  
bDownOver = true; [
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//nPos = fileAccessI.write (b,0,nRead); e=yQFzQT)  
} h>A~..  
catch(Exception e){e.printStackTrace ();} Q`Z=}^  
} 3a_=e B  
} f=f8)+5  
tt=JvI9>  
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//打印回应的头信息 m,TN%*U!  
public void logResponseHead(HttpURLConnection con) 2A5R3x=\  
{ 
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for(int i=1;;i++) Q=+*OQV29  
{ YH 5jvvOI  
String header=con.getHeaderFieldKey(i);
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if(header!=null) oQ=v:P]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); aT[qJbp1  
Utility.log(header+" : "+con.getHeaderField(header)); &:3uK`  
else t04_~e  
break; tcm?qro)  
} R'#1|eWCa  
} 5Wyo!pRi  
hS?pc<~`#  
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public void splitterStop() 3/j^Ao\fw  
{ PqhR^re0.  
bStop = true; &Ti:IC%M  
} AxsTB9/  
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} l[_y|W5  
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/* WPN4mEow  
**FileAccess.java ~o+:M0)}  
*//文件访问(定位，写) {`Jr$*;  
package NetFox; uVQH,NA,  
import java.io.*; n[mVwQ(%  
#DqVh!t"  
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public class FileAccessI implements Serializable{ tJ_6dH8Y  
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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 *i=+["A  
RandomAccessFile oSavedFile; 0# )I:5  
long nPos; [b=l'e/  
 3Y L  
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public FileAccessI() throws IOException /|)VO?*D  
{ B*zR/?U^  
this("",0); $wQk
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} JFJ_ PphvD  
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public FileAccessI(String sName,long nPos) throws IOException 5q.d$K |  
{ {DI
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oSavedFile = new RandomAccessFile(sName,"rw"); 6<uJ}3  
this.nPos = nPos; ^hc&rD)_  
oSavedFile.seek(nPos); Ny\c>$z  
} BotGPk><c  
fpDx)lQ  
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public synchronized int write(byte[] b,int nStart,int nLen) /YyimG7  
{ &sbKN[xM  
int n = -1; w;=fi}<G|e  
try{ WeqE9@V  
oSavedFile.write(b,nStart,nLen); e]1&f.K  
n = nLen; ,vxxp]#5  
} n%SR5+N"  
catch(IOException e) fku\O<1  
{ j[^(<R8  
e.printStackTrace (); d>RoH]K4  
} ed=pRb  
c Nhy.Z~D  
go6
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return n; c7E|GZ2Hc  
} pd3=^Zi  
#[Z1W8e  
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} !4"!PrZDB  
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/* oCCTRLb02  
**SiteInfoBean.java JlM0]__v  
*/ 5-=&4R\k  
package NetFox; 4TPAD)C  
p)dD{+"/2  
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public class SiteInfoBean { b3h3$kIYN  
h^H~q<R[T  
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private String sSiteURL; //Site's URL mMz^I7$  
private String sFilePath; //Saved File's Path F+c4v A})  
private String sFileName; //Saved File's Name $X>$)U'p&-  
private int nSplitter; //Count of Splited Downloading File 8zOoVO  
>Q`\|m}x)Q  
BE#s@-zR=p  
public SiteInfoBean() O/?Lk*r  
{//nSplitter的缺省值为5 d,hKy2
 
//default value of nSplitter is 5 U= Gw(  
this("","","",5); cC NyW2'  
} VssD  
T3JM8  
VV$$t;R/
 
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #835$vOe  
{ /OX;3" +1  
sSiteURL= sURL; #Yqj27&  
sFilePath = sPath; ^#V7\;v$G  
sFileName = sName; "B$r{ vG  
this.nSplitter = nSpiltter; *(?tf{  
]1^F  
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} MnQ4,+ji-  
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public String getSSiteURL() ik;S!S\
v  
{ BDO]-y  
return sSiteURL; Q
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} iB1+4wa  
S5,y!K]C~  
.?Pghqq.  
public void setSSiteURL(String value) [yEH!7  
{ )R- e^Cb  
sSiteURL = value; ac2G;}B|  
} 8F;r$i2  
]y**ZFA  
Yu`KHvur  
public String getSFilePath() ]46-TuH  
{ /`2t$71)  
return sFilePath; G]$.bq[v  
} FUD M]:XQ  
1p|h\H  
&|LP>'H;  
public void setSFilePath(String value) J/{!_M-  
{ u> @Yoyc  
sFilePath = value; PlX6,3F  
} z5UY0>+VdS  
1Fs:&*=  
 hb,G'IU  
public String getSFileName() Mqk[+n  
{ c:@lR/oe"  
return sFileName; Y~fa=
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} i:@n6GW+iw  
:mI[fQ  
|_H{B+.  
public void setSFileName(String value) jkrv2 `"  
{ b14WIgjsl  
sFileName = value; "L)=Y7Dx  
} .Jvy0B} B  
,5 A&  
#% 1|$V*:  
public int getNSplitter() (pud`@D;[  
{ f-'$tM
s  
return nSplitter; Tg-HR8}X  
} Tl%n|pc  
br[n5  
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public void setNSplitter(int nCount) DH*=IzcJf  
{ X *fle  
nSplitter = nCount; /BaXWrd+  
} $&@etsW0/  
} "+BNas^rF  
Ev)a
XP  
8A,="YIt  
/* ;/-X;!a>  
**Utility.java ~Bi{k'A9  
*/ b~L8m4L  
package NetFox; C>0='@LB@r  
L>PPAI  
wvuh   
public class Utility { yrgb6)]nm@  
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public Utility() M?FbBJ`sF  
{ !J%m7A  
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/`x)B(b  
} [-pB}1Dxb  
M%#H>X\/  
//线程睡眠 xdV $dDCT  
public static void sleep(int nSecond) Q&;d7A.@  
{ ]di9dLT  
try{ (d@ =   
Thread.sleep(nSecond); ` 
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} h=`1sfz  
catch(Exception e) I8]q~Q<-P  
{ M,f|.p{,Y  
e.printStackTrace (); %J 'RO
 
} Z"u|-RoBV  
} "p[FFg  
#]_S)_Z-  
//日志 H5'Le{  
public static void log(String sMsg) Z?o?"|o  
{ .}6Mj]7?i  
System.err.println(sMsg); jh*aD=y  
} &
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iI.d8}A  
{k#RWDespy  
public static void log(int sMsg) 5uJ{#Zd  
{ ?{bAyh/  
System.err.println(sMsg); Q x]zz4jD  
} .^} vDA  
} u3XQ<N{Gj  
`Y5{opG7-  
mEM/}]2  
/* `=B0NC.3  
**TestMethod.java }s7ibm'  
*/ |##rs  
package NetFox; C*f3PB=H_  
8pQ:B/3=  
F~Z~OqCS  
public class TestMethod { 5{@Hpj/B  
\a|bx4M  

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public TestMethod() U $ b
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{ ///xx/weblogic60b2_win.exe ~_YU%y  
try{ \;%DDw  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); IRxFcLk  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Wxxnc#;lv  
SiteFileFetch fileFetch = new SiteFileFetch(bean); tHj |_t  
fileFetch.start(); \1p_6U7  
} @A-^~LoP.  
catch(Exception e){e.printStackTrace ();} dLtn,qCX0^  
|4XR [eX  
BW61WH?  
} )ZI9n7  
f/&k$,w  
0qV"R7TW  
public static void main(String[] args) h{sY5d'D  
{ xzRs;AXOp  
new TestMethod(); _%`<V!RT\  
} rLfhm Ds%u  
} Yom,{;B
v  
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