http断点续传简单实现（java)

/* 6@wnF>'/\  
**SiteFileFetch.java [@rZ.Hsl  
*/ =Q.2:*d.  
package NetFox; gEO#-tMjOQ  
import java.io.*; l#~Sh3@L(  
import java.net.*; {u9(qd;;  
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public class SiteFileFetch extends Thread { NX@TWBn%  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ZA1?'  
long[] nStartPos; //开始位置 qOZc}J0  
long[] nEndPos; //结束位置 _S,2j_R9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Mq[;:  
long nFileLength; //文件长度 6[aCjW  
boolean bFirst = true; //是否第一次取文件 Ny*M{}E  
boolean bStop = false; //停止标志 %a8'6^k  
File tmpFile; //文件下载的临时信息 C(}9  
DataOutputStream output; //输出到文件的输出流 b\UQ6V  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ?5$\8gZ  
public SiteFileFetch(SiteInfoBean bean) throws IOException @K4} cP  
{ J0d +q!  
siteInfoBean = bean; x\3 ` W  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 89`AF1  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); O*H:CW  
if(tmpFile.exists ()) MZ=U} &F  
{ }UXj|SY  
bFirst = false; 0Ny0#;P  
read_nPos(); ;?=nr5;q  
} yeE_1C .  
else OJ@';ZyT=  
{ mrqC
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nStartPos = new long[bean.getNSplitter()]; &KbtW_  
nEndPos = new long[bean.getNSplitter()]; M[Y|$I}  
} 70lb6A  
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} dI>)4()  
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public void run() z+PSx'#}  
{ Hi,_qlc+  
//获得文件长度 7R7g$  
//分割文件 S &s7]  
//实例FileSplitterFetch 9.zy`}  
//启动FileSplitterFetch线程 *S~. KW[  
//等待子线程返回 B V+"uF  
try{ :Q+rEjw+  
if(bFirst) f@\ k_  
{ 7Ar4:iNvX  
nFileLength = getFileSize(); >5/dmHPc  
if(nFileLength == -1) 2?QIK3"v  
{ #Sb1oLC  
System.err.println("File Length is not known!"); JP!$uK{u  
} AJt0l|F  
else if(nFileLength == -2) y"e'Gg2  
{ 1'c!9  
System.err.println("File is not access!"); {(D
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} [GhT.  
else MyCX6+Ci)  
{ ~;UK/OZ  
for(int i=0;i<nStartPos.length;i++) )uwpeq$j7l  
{ {* >$aI  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ^5=}Y>EJO  
} ;?=] ffa{  
for(int i=0;i<nEndPos.length-1;i++) \ts:'  
{ G{+sC2  
nEndPos = nStartPos[i+1]; =zqOkC h$  
} PS`)6yn{_  
nEndPos[nEndPos.length-1] = nFileLength; ghbxRnU}  
} n$5,B*  
} a3HT1!M)  
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W qci51y>#  
//启动子线程 MCL?J,1?r  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Y_Ej-u+>{  
for(int i=0;i<nStartPos.length;i++) #96E^%:zL  
{ ecA0z c~  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B wtD!de$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), jBI VZ!X  
nStartPos,nEndPos,i); w^G<]S{l  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O:xRUjpL  
fileSplitterFetch.start(); HxU.kcf  
} q6H90Zb  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !rTh+F*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);  $Jb+}mlT  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", W zy8  
nEndPos = " + nFileLength); W$?1" F.  
// fileSplitterFetch[nPos.length-1].start(); eoTOccb!  
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//等待子线程结束 1
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//int count = 0; 9WtTUk
 
//是否结束while循环 OR1XQij  
boolean breakWhile = false; mOGcv_L  
:!g|0CF_  
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while(!bStop) ,6i67!lb  
{ .s7o$u~l  
write_nPos(); (yc$W9  
Utility.sleep(500); y ?4|jN  
breakWhile = true; r A0[y  
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for(int i=0;i<nStartPos.length;i++) 9e=F  
{ 1swh7  
if(!fileSplitterFetch.bDownOver) /~J#c=  
{ 0/{-X[z  
breakWhile = false; aJI>qk h?]  
break; Yfxc$ub  
} Mgcq'{[~Y=  
} k5g\s9n]  
if(breakWhile) =J0FT2 d  
break; DrHMlk5  
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//count++; Qi6vP&  
//if(count>4) Zm&Zz^s  
// siteStop(); 8{%/!ylJz  
} L!mQP  
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System.err.println("文件下载结束！"); 1m}'Y@I  
} rZ:  
catch(Exception e){e.printStackTrace ();} &rcr])jg[  
} W 86S)+h  
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!
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//获得文件长度 }-: d*YtK  
public long getFileSize() () b0Sh=  
{ 1PLKcU  
int nFileLength = -1; (:Bo'q S  
try{ 2rPKZ|  
URL url = new URL(siteInfoBean.getSSiteURL()); <(3Uu()   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ls*.=ARq  
httpConnection.setRequestProperty("User-Agent","NetFox"); GlQ=M)E  
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int responseCode=httpConnection.getResponseCode(); k(%RX_]C  
if(responseCode>=400) $dorE~T  
{ +-qD!(&-6  
processErrorCode(responseCode); '~3(s?B  
return -2; //-2 represent access is error cX*  
}  78qf  
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?  
String sHeader; 3,N7Nfe  
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for(int i=1;;i++) sE>'~+1_O  
{ z_A%>E4  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); WYEvW<Hv  
//Utility.log(in.readLine()); 3i35F.=X,  
sHeader=httpConnection.getHeaderFieldKey(i); ^]E| >~\  
if(sHeader!=null) /*rMveT  
{ oDKgW?x  
if(sHeader.equals("Content-Length")) Pbm;@V  
{ 
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9FPl  
break; Cv;z^8PZJz  
} `n5RDz/f0  
} z0g$+bhy  
else }@1LFZx
 
break; ^Ud`2 OW;2  
} tet  
} "TN}=^A\F  
catch(IOException e){e.printStackTrace ();} 2R<1^  
catch(Exception e){e.printStackTrace ();} 6D0uLh  
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Utility.log(nFileLength); Sq(=Bn6E  
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return nFileLength; EMs$~CL4  
} kIXLB!L2b^  
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-VRu^l#  
//保存下载信息（文件指针位置） 3'1O}x
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private void write_nPos() LjxTRtB_  
{ &^&k]JBaV  
try{ _ogT(uYyr  
output = new DataOutputStream(new FileOutputStream(tmpFile));  $JX_e  
output.writeInt(nStartPos.length);  0Apvuf1  
for(int i=0;i<nStartPos.length;i++) W{Nhh3  
{ {(xNC#
  
// output.writeLong(nPos); IXd&$h]Lq  
output.writeLong(fileSplitterFetch.nStartPos); EWH'x$z_q  
output.writeLong(fileSplitterFetch.nEndPos); w :^b3@gd  
} g*Cs/w  
output.close(); { 
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} (">!vz  
catch(IOException e){e.printStackTrace ();} 5%tIAbGW  
catch(Exception e){e.printStackTrace ();} Z~$&
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} I&
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//读取保存的下载信息（文件指针位置） +=O8t0y n  
private void read_nPos() kw=+"U  
{ ^f3F~XhY3  
try{ sVh!5fby&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));
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int nCount = input.readInt(); B;G|2um:$  
nStartPos = new long[nCount]; o
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nEndPos = new long[nCount]; `[o^w(l:5@  
for(int i=0;i<nStartPos.length;i++) 8a-[Q  
{ S~Nx;sB  
nStartPos = input.readLong(); C7qbofoV  
nEndPos = input.readLong(); of{wZU\J+9  
} L & PhABZ  
input.close(); LuQ=i`eXx  
} u!{P{C  
catch(IOException e){e.printStackTrace ();} nM}X1^PiK"  
catch(Exception e){e.printStackTrace ();} #C!8a  
} {u9VHAXCf  
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2
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private void processErrorCode(int nErrorCode) ~>#=$#V   
{ ,Sz*]X  
System.err.println("Error Code : " + nErrorCode);  /H!I90  
} q/%f2U%4:  
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//停止文件下载 LvW9kL+WiQ  
public void siteStop() $C^94$W  
{ S=M$g#X`5  
bStop = true; JNX7]j\  
for(int i=0;i<nStartPos.length;i++) "v^Q !  
fileSplitterFetch.splitterStop(); $i~DUT(  
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} s "*Cb*  
} $?;aW^E  
//负责部分文件的抓取 OZk(VMuI  
**FileSplitterFetch.java lBPZB%  
*/ t0}3QGf;c  
package NetFox; 5QMu=/  
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import java.io.*; {\lu; b!  
import java.net.*; O`|'2x{[O  
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public class FileSplitterFetch extends Thread { CS6,mX  
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String sURL; //File URL #
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long nStartPos; //File Snippet Start Position Xg.\B1d  
long nEndPos; //File Snippet End Position r7w&
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int nThreadID; //Thread's ID >Qt#6X|  
boolean bDownOver = false; //Downing is over mC J/gWDY  
boolean bStop = false; //Stop identical FV:{lC{h~  
FileAccessI fileAccessI = null; //File Access interface SDdK5@1O4o  
"R):B~8|H{  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ::adT=  
{ &\c$s  
this.sURL = sURL; rj<%_d'Z`  
this.nStartPos = nStart; `2S%l,>)#  
this.nEndPos = nEnd; p~=%CG^5  
nThreadID = id; Kw925@W  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !|Vjv}UO  
} S>cT(q_&  
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public void run() i3#]_ p{  
{ o+6Y/6Xp@  
while(nStartPos < nEndPos && !bStop) 1VJE+3  
{ ,n&Dg58K  
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try{ WY<ip<  
URL url = new URL(sURL); tTQ>pg1{qh  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); PjRKYa_U  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3tOnALv  
String sProperty = "bytes="+nStartPos+"-"; QE-t v00  
httpConnection.setRequestProperty("RANGE",sProperty); CEI#x~Oq  
Utility.log(sProperty); 8
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InputStream input = httpConnection.getInputStream(); 2R|2yAh  
//logResponseHead(httpConnection); 0/-[k  
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byte[] b = new byte[1024]; 2+y4Gd 7  
int nRead; _3kAN.g  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) iCz,|;w%  
{ =o+t_.)N  
nStartPos += fileAccessI.write(b,0,nRead); Lqwc:%Y:_  
//if(nThreadID == 1) g($y4~#  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
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} ~-'nEATE  
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Utility.log("Thread " + nThreadID + " is over!"); Pm" ,7  
bDownOver = true; L;gr
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//nPos = fileAccessI.write (b,0,nRead); Pf(z0o&  
} 5 _] i==M  
catch(Exception e){e.printStackTrace ();} ydoCoD w  
} u~a<Psp&|  
} 'nW:2(J  
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//打印回应的头信息 2/(gf[elX  
public void logResponseHead(HttpURLConnection con) CX\# |Q8q  
{ LTFA2X&E=  
for(int i=1;;i++) y{"8VT)  
{ L88
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String header=con.getHeaderFieldKey(i); lD 9'^J  
if(header!=null) )UN@|IX  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); DQ~+\  
Utility.log(header+" : "+con.getHeaderField(header)); H-0deJ[>  
else ]TD]
  
break; vW YN?"d  
} wGb{O  
} %Z.>)R4  
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public void splitterStop() 2nOQ48haT  
{ RwY) O5  
bStop = true; &eg]8kV  
} =}_c=z?UY  
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} q$U;\Mg)  
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/* KRm4r  
**FileAccess.java >Li ~Og@  
*//文件访问(定位，写) rZGA9duy  
package NetFox; =cqaA^HQL  
import java.io.*; Mt-y{*6!k  
l ^$$d8  
SE%i@}  
public class FileAccessI implements Serializable{ *>Om3[D  
Z1OX9]##r  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Y$Os&t@bu  
RandomAccessFile oSavedFile; (
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long nPos; 1!BV]&,[  
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public FileAccessI() throws IOException 42Ql^ka  
{ $mp7IZE|  
this("",0); Lf7
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} ,]20I _  
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public FileAccessI(String sName,long nPos) throws IOException >8jDW "Ua  
{ 5M*q{kX)  
oSavedFile = new RandomAccessFile(sName,"rw"); ZhM-F0;`  
this.nPos = nPos; o<T>G{XYB  
oSavedFile.seek(nPos); dI'C[.zp[  
} .r]n<  
.hZ =8y9  
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public synchronized int write(byte[] b,int nStart,int nLen) aLhTaB-va  
{ zKgW9j<(  
int n = -1; *1%=?:$(r6  
try{ ?MO'WB9+JR  
oSavedFile.write(b,nStart,nLen); `4Nc(aUr  
n = nLen; `4l>%S8y:  
} [NaU\;w\  
catch(IOException e) Gf]oRNP,N  
{ AB+Zc ]  
e.printStackTrace (); $3"0w   
}  Zp]Bs  
rA{h/T"  
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return n; m0
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} EYG&~a>L*  
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} ^W#[6]S  
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/* 'KyT]OObS  
**SiteInfoBean.java |oO0%#1H  
*/ bu@Pxz%_  
package NetFox; *GD 1[:  
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|%6B#uy  
public class SiteInfoBean { w&C SE  
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private String sSiteURL; //Site's URL o)1wF X  
private String sFilePath; //Saved File's Path lywcT
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private String sFileName; //Saved File's Name 1\zI#"b ^  
private int nSplitter; //Count of Splited Downloading File Zj`eR\7~  
TX;OA"3=\-  
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public SiteInfoBean() .8.ivfmJh  
{//nSplitter的缺省值为5 )@))3  
//default value of nSplitter is 5 EKwS~G.b!  
this("","","",5); r+$ 0u~^  
} Z(U&0GH`  
I+u=H2][2  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \gIdg:"02  
{ US> m1KsX  
sSiteURL= sURL; Uc7X)  
sFilePath = sPath; x1A^QIuxO  
sFileName = sName; AO^F6Y/  
this.nSplitter = nSpiltter; `EWeJ(4Z@  
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4p %`
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} !?Ow"i-lp  
)t)tk=R9N  
dqd Qt_  
public String getSSiteURL() B%'Np7  
{ vi lNl|
 
return sSiteURL; ,wZ[Y 3  
} xB9^DURr\  
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H
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public void setSSiteURL(String value) >@]E1Qfe  
{ ;'p0"\SV  
sSiteURL = value; 73N%_8DH  
} a.w,@!7  
#gsAwna3  
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public String getSFilePath() <NS=<'U  
{
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return sFilePath; 5]'iSrp  
} S0p]:r";x  
E 8,53$  
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public void setSFilePath(String value) Prjl ;[I}  
{ X*FK6,Y|(  
sFilePath = value; : PQA9U|  
} O
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rm(  
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public String getSFileName() @h^5*M  
{ gdkO|x  
return sFileName;  hA/FK  
} 8U\ +b?}  
ncS^NH(&  
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public void setSFileName(String value) q
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{ t'[vN~I'  
sFileName = value; i37W^9 R  
} QW~o+N~~  
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pRt )B`#  
public int getNSplitter() gvwR16N  
{ %J+$p\c  
return nSplitter; "gK2!N|#  
} YZ*Si3L  
1X#`NUJ?2  

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public void setNSplitter(int nCount) xES+m/?KlZ  
{ 6EPC$*Xp!  
nSplitter = nCount; drb_GT  
} #uey1I@"9  
} &,KxtlR![  
;39{iU.m  
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/* UbMcXH8=F  
**Utility.java xFyMg&  
*/ !q7M+j4  
package NetFox; #2cH.`ty  
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public class Utility { [a+?z6qI\}  
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YK}(
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public Utility() Qt@~y'O  
{ tgrQ$Yjk  
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} L;BYPZR  
YW/<. 0rI  
//线程睡眠 KP:O]520  
public static void sleep(int nSecond) U*6-Y%7  
{ @br%:Nt  
try{ L^ +0K}eD  
Thread.sleep(nSecond); 75^-93  
} jhg!K.A  
catch(Exception e) A;Zg:  
{ JaIj9KLNX  
e.printStackTrace (); W^yF5  
} L`"cu.l  
} f_z2d+  
czHO)uQ?d`  
//日志 VfZ/SByh7p  
public static void log(String sMsg) 2\s-4H| q  
{ yn%w'  
System.err.println(sMsg); co~TQpy^  
} <(^-o4Cl  
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public static void log(int sMsg) ^[id
8  
{ 4|XE f,  
System.err.println(sMsg); hs/nM"V  
} +x+H(of.  
} "bw4{pa+  
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/* jl7e6#zu  
**TestMethod.java EoOrA@N  
*/ (tVY /(~#  
package NetFox; IE,g  
[
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public class TestMethod { Wt4!XV  
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public TestMethod() wI`uAZ="  
{ ///xx/weblogic60b2_win.exe 4vy!'r@  
try{ Hq%`DWus\  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); &"L3U  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); jMw;`yh  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (:hPT-1  
fileFetch.start(); Gt 2rJ<>  
} }. ,xhF[  
catch(Exception e){e.printStackTrace ();} 3w^q0/GD  
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O %)+ w  
} F*]AjD-  
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public static void main(String[] args) <:%Iq13D  
{ YJ:CqTy  
new TestMethod(); Duz}e80  
} NghQ#c  
} 2+Fq'!  
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