http断点续传简单实现（java)

/* %uua_&#)  
**SiteFileFetch.java x df?nt  
*/ "ct58Y@  
package NetFox; QhsVIta  
import java.io.*; 3 &Sp@,  
import java.net.*; S_$nCyaH2  
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public class SiteFileFetch extends Thread { ;5N41_hG  
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SiteInfoBean siteInfoBean = null; //文件信息Bean q=+wI"[  
long[] nStartPos; //开始位置 'mJ1
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long[] nEndPos; //结束位置 k/@Tr
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 oBC]UL;8xJ  
long nFileLength; //文件长度 `|,Bm|~:  
boolean bFirst = true; //是否第一次取文件 9>;} /*:H  
boolean bStop = false; //停止标志 7VY8CcL  
File tmpFile; //文件下载的临时信息 Fo(y7$33*  
DataOutputStream output; //输出到文件的输出流 6<PW./rk:  
` jyKCm.$#  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） {m'AY)  
public SiteFileFetch(SiteInfoBean bean) throws IOException vzG ABP  
{ ;Gh>44UM[  
siteInfoBean = bean; J 3B`Krh  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); {!r#f(?uT  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;?`@"YG)  
if(tmpFile.exists ()) C5MqwNX  
{ *E7R(#,yC  
bFirst = false; fK"iF@=Z`  
read_nPos(); c$A@T~$  
} kP?_kMOx  
else {mf.!Xev
 
{ 7D
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nStartPos = new long[bean.getNSplitter()]; V)h
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nEndPos = new long[bean.getNSplitter()]; #Wk5E2t  
} QtlT&|$   
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} OpUA{P  
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public void run() aj v}JV&:  
{ \4QH/e  
//获得文件长度 U(Z!J6{c  
//分割文件 y!5:dvt  
//实例FileSplitterFetch N iISJWk6'  
//启动FileSplitterFetch线程 &mdB\Y?^  
//等待子线程返回 NWaO_sm  
try{ HU9p!I.  
if(bFirst) ~1ps7[  
{ HzEGq,.  
nFileLength = getFileSize(); nALnB1  
if(nFileLength == -1) LuL$v+`  
{ {G%3*=?,j  
System.err.println("File Length is not known!"); O4!9{  
} ll2Vk*xs  
else if(nFileLength == -2) h1c{?x
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{ dQK`sLChv  
System.err.println("File is not access!"); X|Dpt2A=  
} 8JP6M!F#  
else H0+:XF\M  
{ lvPpCAXY  
for(int i=0;i<nStartPos.length;i++) OEI3eizgH  
{ +(y>qd  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 6%UY1Q.?  
} Vmtzig3w[  
for(int i=0;i<nEndPos.length-1;i++) vzcz<i )  
{ J?,?fqb  
nEndPos = nStartPos[i+1]; cd+^=esSO  
} ;:?*t{r4#  
nEndPos[nEndPos.length-1] = nFileLength; AA2ui%  
} Z'e\_C  
} cyBW0wV1  
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//启动子线程 |@ *3^'  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; K-6p'|  
for(int i=0;i<nStartPos.length;i++) +dM.-wW  
{ 71*>L}H  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), PF67z]<o  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), v4C3uNW  
nStartPos,nEndPos,i); ee^4KKsh\  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jr:drzr{I  
fileSplitterFetch.start(); |eF.ZC)QWh  
} ,H@
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), b*`fLrqV.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); CC>($k"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", L&QtHSzy  
nEndPos = " + nFileLength); Q K j1yG0i  
// fileSplitterFetch[nPos.length-1].start(); $bFgsy*N2  
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//等待子线程结束 u]0!|Jd0  
//int count = 0; zu<>"5}]  
//是否结束while循环 :v#8O~
  
boolean breakWhile = false; ey*,StT5a  
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while(!bStop) j C9<hLt  
{ %]!?{U\*k  
write_nPos(); ExQ--!AC=  
Utility.sleep(500); w~]}
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breakWhile = true; @BXaA0F4  
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for(int i=0;i<nStartPos.length;i++) R@&?i=gk  
{ GajI\_o  
if(!fileSplitterFetch.bDownOver) ah>Dqb*  
{ =^by0E2  
breakWhile = false; eiOi3q  
break; /CbkqNV  
} sv@}x[L  
} X!m;uJZp  
if(breakWhile) F
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break; m8
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//count++; 7;~2e  
//if(count>4) (Y&R0jt  
// siteStop(); UX?X]ZYVR  
} ^g\h]RD}  
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System.err.println("文件下载结束！"); Y/#:)(&@  
} :LG}yq^  
catch(Exception e){e.printStackTrace ();} g}^4^88=a  
} MV7}  
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//获得文件长度 *'s&/vEy  
public long getFileSize() Z5 w`-#  
{ ^o,y5,  
int nFileLength = -1; <ihhV e  
try{ |P^ikx6f5  
URL url = new URL(siteInfoBean.getSSiteURL()); /%c+ eL}l  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `>$gy/N  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^Jc$BMaVg  
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int responseCode=httpConnection.getResponseCode(); Z{Lmd`<w`j  
if(responseCode>=400) ,%& LG],6  
{ }S1Z>ZA5  
processErrorCode(responseCode); _gis+f/8h  
return -2; //-2 represent access is error +F#=`+V  
} 
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String sHeader; ?
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for(int i=1;;i++) T9&,v<f  
{ h Kp,4D>2_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); yHV^a0e7EH  
//Utility.log(in.readLine()); `Pz!SJ|  
sHeader=httpConnection.getHeaderFieldKey(i); .2 N_?
  
if(sHeader!=null) !07FsPI#{  
{ N>uZt2  
if(sHeader.equals("Content-Length")) HXlr  
{ A,-[/Z K/  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); bqf]$}/8k  
break; V{/)RZ/  
} fS8XuT  
} qkZ5+2m  
else ,Yiq$Z{qQ  
break; Gx~"iM  
} *IjdN,wox  
} Ynk><0g6  
catch(IOException e){e.printStackTrace ();} dd @COP?  
catch(Exception e){e.printStackTrace ();} W}<M?b4tP  
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Utility.log(nFileLength); [|m>vY!  
|{}d5Z"5;}  
}(vOaD|k=  
return nFileLength; 
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} :*w:eKk  
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//保存下载信息（文件指针位置） Xoa<r9  
private void write_nPos() JXI+k.fi  
{ $HR(|{piZ  
try{ Nsy9 h}+A  
output = new DataOutputStream(new FileOutputStream(tmpFile)); w$<fSe7  
output.writeInt(nStartPos.length); <|>:UGAR  
for(int i=0;i<nStartPos.length;i++) =O}%bZ)Q  
{ R;Ix<y{U  
// output.writeLong(nPos); C>(
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output.writeLong(fileSplitterFetch.nStartPos); q}7Df!<|  
output.writeLong(fileSplitterFetch.nEndPos); {H7$uiq3:B  
} Z:o' +oh  
output.close(); Af! W K=  
} 7+2aG  
catch(IOException e){e.printStackTrace ();} bju,p"J1-E  
catch(Exception e){e.printStackTrace ();} +XaO?F[c  
} XH Zu>[  
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//读取保存的下载信息（文件指针位置） ju2X*  
private void read_nPos() N4GIb 6  
{ 3Jk?)Dy  
try{ y[7xK}`_  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); /\Y%DpG$  
int nCount = input.readInt();
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nStartPos = new long[nCount]; !?>p]0*<  
nEndPos = new long[nCount]; v.8S V
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for(int i=0;i<nStartPos.length;i++) cK}  
{ T;pn -  
nStartPos = input.readLong(); J;]@?(  
nEndPos = input.readLong(); 9Q
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} -r2qIt  
input.close(); 8@C|exAD`  
} 5<GRi"7A@  
catch(IOException e){e.printStackTrace ();} ,9j:h)ks?  
catch(Exception e){e.printStackTrace ();} W&re;?Z{ke  
} 9,a,A6xry  
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private void processErrorCode(int nErrorCode) Cot\i\]jv  
{ L"^366M!  
System.err.println("Error Code : " + nErrorCode); 36Y[7m=  
} r#Oz0=0u  
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//停止文件下载 7;-i_&vws  
public void siteStop() 9TN
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{ -/{}^QWB  
bStop = true; WsDe0F  
for(int i=0;i<nStartPos.length;i++) =X'7V}Q}  
fileSplitterFetch.splitterStop(); M[N.H9  
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} <%JO3E  
} L;t~rW!1  
//负责部分文件的抓取 "LaX_0t)  
**FileSplitterFetch.java 29DWRJU  
*/ [MP:Eeg  
package NetFox; ? Z fhz  
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import java.io.*; &bgi0)>  
import java.net.*; _%%"Y}  
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public class FileSplitterFetch extends Thread { yzl\{I&  
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String sURL; //File URL 1Sk6[h'CL  
long nStartPos; //File Snippet Start Position M:f=JuAx  
long nEndPos; //File Snippet End Position ?Gw89r  
int nThreadID; //Thread's ID ,w>?N\w!}  
boolean bDownOver = false; //Downing is over cHct|Z u  
boolean bStop = false; //Stop identical .g?,:$`0D?  
FileAccessI fileAccessI = null; //File Access interface xmx;tq  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?tQv|x  
{ >g2
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this.sURL = sURL; Pk_{{Z(1o  
this.nStartPos = nStart; V3UGx'@^y  
this.nEndPos = nEnd; HNT8~s.2  
nThreadID = id; DK%eFCo<~  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 zD-8#H35X"  
} R?SHXJ%'  
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public void run() EBLoRW=8ld  
{ r
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while(nStartPos < nEndPos && !bStop) tpK4 gjf  
{ m/Z_HER^  
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try{ !{;RtUPz*  
URL url = new URL(sURL); Ts6X:D4,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :nEV/"#F  
httpConnection.setRequestProperty("User-Agent","NetFox"); ro@BmRMW  
String sProperty = "bytes="+nStartPos+"-"; &nProzC  
httpConnection.setRequestProperty("RANGE",sProperty); .5xg;Qg\Y  
Utility.log(sProperty); jp`N%O]6  
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InputStream input = httpConnection.getInputStream(); rgY~8PY"  
//logResponseHead(httpConnection); Wz]S+IpY  
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byte[] b = new byte[1024]; pnU g:R@  
int nRead; Y~xZ{am  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ,L G&sa"  
{ H_FhHX.2(  
nStartPos += fileAccessI.write(b,0,nRead); _T$\$v$ {  
//if(nThreadID == 1) 'CX KphlWs  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qT4s*kqr  
} U_No/$ b  
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Utility.log("Thread " + nThreadID + " is over!"); E.9F~&DPJ<  
bDownOver = true; _?ZT[t<  
//nPos = fileAccessI.write (b,0,nRead); :*1w;>o)n  
} T2{+fRvN  
catch(Exception e){e.printStackTrace ();} '\Ub*m((1O  
} 4SYN$?.Mp  
} 51
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//打印回应的头信息 Gf?KpU  
public void logResponseHead(HttpURLConnection con) LHb{9x  
{ x-<dJ}`  
for(int i=1;;i++) ; F=_ozWV*  
{ j4h 7q<  
String header=con.getHeaderFieldKey(i); _*9Zp1r  
if(header!=null) Gu=Rf`o  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 7}Sw(g)o7  
Utility.log(header+" : "+con.getHeaderField(header)); =%L^!//c  
else 9O"?T7i"#  
break; C N"c  
} }/VHeHd  
} R|suBF3  
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public void splitterStop() fp7Qb $-A  
{ }=U\v'%m  
bStop = true; 1}6pq2  
} p,Z6/e[SI  
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} C$bK!]a  
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/* 7v-C-u[E`  
**FileAccess.java *M"wH_cd  
*//文件访问(定位，写) <n><A+D  
package NetFox; MiC
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import java.io.*; ?o4&cCFOE  
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m[}$&i$(  
public class FileAccessI implements Serializable{ 4=9F1[  
te|VKYN%}[  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `drvu?F  
RandomAccessFile oSavedFile; @.})nU  
long nPos; ESO(~X+  
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public FileAccessI() throws IOException %$cwbh-{{  
{ b,cvQD  
this("",0); 78X;ZMY  
} >$?Z&7Lv  
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public FileAccessI(String sName,long nPos) throws IOException {*|y
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{ F :u}7t>  
oSavedFile = new RandomAccessFile(sName,"rw"); &~k/G  
this.nPos = nPos; D\k);BU~  
oSavedFile.seek(nPos); #*9*[Xbi  
} X)yTx8v4  
i->sw#  
,^
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public synchronized int write(byte[] b,int nStart,int nLen) E5o0^^  
{ #&@&BlIe  
int n = -1; 8^^al!0K~  
try{ nK:39D$(  
oSavedFile.write(b,nStart,nLen); aqMZ%~7  
n = nLen; _|*j8v3  
} ^iGIF~J9  
catch(IOException e) @<};Bo'  
{ P$!Ht  
e.printStackTrace (); 
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} 5Zq- |"|  
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return n; *kDXx&7B$  
} [0 W^|=#K  
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} .M_;mhRI  
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/* lRO4- y  
**SiteInfoBean.java OyH
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*/ h IGa);g  
package NetFox; 9 /9,[A  
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public class SiteInfoBean { 4ba1c  
!{SEm"J^  
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private String sSiteURL; //Site's URL B$7lL
  
private String sFilePath; //Saved File's Path Wve ^2lkoK  
private String sFileName; //Saved File's Name 6R?J.&|  
private int nSplitter; //Count of Splited Downloading File 4=1lyw  
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-,Q<*)q{  
public SiteInfoBean() |R+=Yk&u  
{//nSplitter的缺省值为5 eNXpRvY  
//default value of nSplitter is 5 YrB-;R1+  
this("","","",5); M>0~Ek%3  
} RRV&!<l@$  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) S_\RQB\l  
{ 4h(aTbHaQ  
sSiteURL= sURL; J H$  
sFilePath = sPath; #ReW#?P%b/  
sFileName = sName; ~>{<r{H"S  
this.nSplitter = nSpiltter; \Ud2]^D=  
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} dAga(<K  
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public String getSSiteURL()
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{ 0{Tf;
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return sSiteURL; FmnA+fA  
} {5*+  
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public void setSSiteURL(String value) x%$Z/  
{ ,kLeK{  
sSiteURL = value; ]QpR>b=[j  
} 5nEvnnx0  
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,(lD5iN  
public String getSFilePath() Xf#uK\f  
{ .p0;y3so4  
return sFilePath; sba0Q[IY  
} -[+FVvS  
$|AvT;4  
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public void setSFilePath(String value) CuDU~)`  
{ 1OJ:Vy}n  
sFilePath = value; :%s9<g;-h_  
} 6`EyzB%.$  
b
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public String getSFileName() hWuq  
{ J&h 3,  
return sFileName; ZP?](RV>xg  
} W6]iJ  
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public void setSFileName(String value) DfqXw^BKD  
{ 8
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sFileName = value; sd>#Hn
 
} R'&^)_  
<sd Qvlx$-  
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public int getNSplitter() =g?r.;OO  
{ o1YhYA  
return nSplitter; l1!i3m'x  
} Br-
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public void setNSplitter(int nCount) <w08p*?  
{ T,jxIFrF  
nSplitter = nCount; 0wxQ,PI1'  
} "PnYa)?1  
} c1b@3  
+X.iJ$)  
r+\it&cW+  
/* H2rh$2  
**Utility.java (9'MdH  
*/ 7Nx@eoZ  
package NetFox; *}3~8fu{  
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public class Utility { kU4Zij-O  
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public Utility() 0jE,=<W0>  
{ 7|IW\  
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} $ 'HiNP {c  
;%Jp@'46  
//线程睡眠 ;/>~|@  
public static void sleep(int nSecond) AaKILIIQZ  
{ />)>~_-3  
try{ Y"G$^3% (]  
Thread.sleep(nSecond); rDm>R
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} ~r&Q\G  
catch(Exception e) Cg8{NNeD  
{ 7A7K:,c  
e.printStackTrace (); \>1M?  
} Y==# yNwM  
} '^lrGO6 z7  
0Rrz   
//日志 V ;"?='vVe  
public static void log(String sMsg) OjyS ?YY)b  
{ GsE?<3  
System.err.println(sMsg); q>!T*BQ  
} B_c(3n-"  
(;C_>EL&u  
$(#o)r>_R  
public static void log(int sMsg) K#+TCZ,  
{ LP#CA^*S  
System.err.println(sMsg); Y13IrCA2  
} G@ed2T  
} :8yrtbf$  
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+- c#UO
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/* qt/"$
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**TestMethod.java <$,iYx  
*/ 8t9sdqM/C  
package NetFox; \`|,wLgH  
&hjrJ/'^  
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public class TestMethod { VO. Y\8/  
Ya304Pjd  
DCP"  
public TestMethod() hFylQfd  
{ ///xx/weblogic60b2_win.exe "R4~ 8r  
try{ $N:m 9R  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); d=N5cCqq  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); u&2uQ-T0  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [C P V5\2  
fileFetch.start(); =xai 7iM  
} U>ob)-tl  
catch(Exception e){e.printStackTrace ();} \muyL?  
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;(VJZ_
 
} ]+d.X]  
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?HZ+fS,-  
public static void main(String[] args) :%!=Ej.J  
{ )k0bP1oGS  
new TestMethod(); /HI#8  
} Ca?pK_Y  
} AO>K 6{  
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