http断点续传简单实现（java)

/* tt%lDr1A)  
**SiteFileFetch.java %YhM?jMW  
*/ :RqTbE4B  
package NetFox; HK/T`p#  
import java.io.*; ^Hplrwj}  
import java.net.*; AlH\IP  
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public class SiteFileFetch extends Thread { 2y"|l  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ]a ,H!0i  
long[] nStartPos; //开始位置 Vui
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long[] nEndPos; //结束位置 `62iW3y  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 P_:~!+W,  
long nFileLength; //文件长度 ":G\  
boolean bFirst = true; //是否第一次取文件 'Drz6K_KrP  
boolean bStop = false; //停止标志 wQnW2)9!  
File tmpFile; //文件下载的临时信息 LKx<hl$O  
DataOutputStream output; //输出到文件的输出流 SD=kpf;  

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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） o/6'g)r*  
public SiteFileFetch(SiteInfoBean bean) throws IOException hh$V[/iK  
{ i!U,qV1  
siteInfoBean = bean; W-ctx"9DS  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ux 7^PTgcO  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Te:
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if(tmpFile.exists ()) ;hcOD4or  
{ uv}?8$<\  
bFirst = false; 10C,\  
read_nPos(); }0%~x,  
}  oRbG6Vv/  
else ,{tK{XpS  
{ `RriVYc<  
nStartPos = new long[bean.getNSplitter()]; z
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nEndPos = new long[bean.getNSplitter()]; oU`J~6.&S  
} l^ Q-KUI  
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} T/b%,!N)  
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public void run() e=yQFzQT)  
{ 82z\^a  
//获得文件长度 &/}reE*  
//分割文件 Q`Z=}^  
//实例FileSplitterFetch +wwb+aG6{  
//启动FileSplitterFetch线程 t[yu3U  
//等待子线程返回 f=f8)+5  
try{ pm.Zc'23  
if(bFirst) ioZ{2kK  
{ YKk*QcAn  
nFileLength = getFileSize(); 1_aUU,|.  
if(nFileLength == -1) ("+J*u*kq_  
{ 8^8fUN4<=  
System.err.println("File Length is not known!"); 2(<2Gnpl  
} { !;I4W%!  
else if(nFileLength == -2) 2c Pd$j  
{ l[G&=/R@H  
System.err.println("File is not access!"); h:J0d~u  
} vs`"BQYf  
else t\/i9CBn  
{ 3b#eB  
for(int i=0;i<nStartPos.length;i++) i 1{Lx)  
{
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); _3_kvs  
} L T.u<ThR}  
for(int i=0;i<nEndPos.length-1;i++) tE~OWjL  
{ 9MI~yIt`L  
nEndPos = nStartPos[i+1]; g<@P_^vo  
} "Q>gQKgL  
nEndPos[nEndPos.length-1] = nFileLength; LxcC5/@\~(  
} VD,p<u{r  
} \m\E*c ):  
PqhR^re0.  
6hW ~Q  
//启动子线程 WaaF;|,(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; g$(<wWsU  
for(int i=0;i<nStartPos.length;i++)  3)bC,  
{ [i&EUvo  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), O:'ENoQ:&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), gHB*u!w7Z  
nStartPos,nEndPos,i); pr;z>|FgA>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &N`s@K
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fileSplitterFetch.start(); a___SYl 'K  
} mw[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), HVq02 Z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;AjY-w  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Q|gRBu  
nEndPos = " + nFileLength); ^~iFG+g5  
// fileSplitterFetch[nPos.length-1].start(); tz).]E D  
8c6dTT4  
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//等待子线程结束 s"7$SxMT  
//int count = 0; OrZ=-9"  
//是否结束while循环 s5 P~feg  
boolean breakWhile = false; .:`+4n  
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!ULU#2'1  
while(!bStop) eLvbPE_  
{ 6ojEEM  
write_nPos(); E6=JL$"  
Utility.sleep(500); '1jG?D  
breakWhile = true; -F-RWs{yS  
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for(int i=0;i<nStartPos.length;i++) aLWNqe&1  
{ swfcA\7R  
if(!fileSplitterFetch.bDownOver) |\ZsoA  
{ ?bq S{KF  
breakWhile = false; fW'@+<b  
break; /|)VO?*D  
} Ji#"PE/Pt  
} 5Dhpcgq<<  
if(breakWhile) {D6E@a  
break; >\/H2j  
h0=Q.Yz6  
"RkbT O  
//count++; HkP')= sa  
//if(count>4) n' Xv
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// siteStop(); D^[}:O{  
} em@bxyMm  
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System.err.println("文件下载结束！"); sp/l-a  
} FRSz3^Aw  
catch(Exception e){e.printStackTrace ();} iPD5 KsAOA  
} &?#,rEw<x  
mr4W2Z@L  
~
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//获得文件长度 "M GX(SQ  
public long getFileSize() sW53g$`v  
{ H(JgqbFB*  
int nFileLength = -1; +5zLQ>]z  
try{ d-W@/J  
URL url = new URL(siteInfoBean.getSSiteURL()); (eG9b pqr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t7t?xk!2  
httpConnection.setRequestProperty("User-Agent","NetFox"); WeqE9@V  
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int responseCode=httpConnection.getResponseCode(); ,vxxp]#5  
if(responseCode>=400) *tWZ.I<<  
{ Y`O"+Jr  
processErrorCode(responseCode); fku\O<1  
return -2; //-2 represent access is error X J+y5at  
} pBd_BaN  
/|kR=
~  
\A{ [2  
String sHeader; p}b:(QN~m  
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for(int i=1;;i++) <~%e{F:[#  
{

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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); e(5:XHe  
//Utility.log(in.readLine()); :jJ;&t^^  
sHeader=httpConnection.getHeaderFieldKey(i);  .IO_&^  
if(sHeader!=null) k2"DFXsv  
{ c]eDTbXd  
if(sHeader.equals("Content-Length")) !4"!PrZDB  
{ 8|Q=9mmWOh  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); MHuQGc"e+4  
break; 'aWrjfD
y:  
} 9*thqs3J#d  
} g
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else d(=*@epjR  
break; MRI`h.  
} #><P28m  
} ]uikE2nn  
catch(IOException e){e.printStackTrace ();} JQo"<<[  
catch(Exception e){e.printStackTrace ();} bv NXA*0  
V!|:rwG2  
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Utility.log(nFileLength); n^a&@?(+  
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return nFileLength; l/wdu(  
} IbC8DDTD  
,y>%m;jL  
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//保存下载信息（文件指针位置） @hb K  
private void write_nPos() |8|_^`  
{ L"_l(<g  
try{ oy;g;dtq  
output = new DataOutputStream(new FileOutputStream(tmpFile)); :EkhF6B/  
output.writeInt(nStartPos.length); cE|Z=}4I7  
for(int i=0;i<nStartPos.length;i++) ]c Or$O*  
{ b3zxiq x  
// output.writeLong(nPos); D
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output.writeLong(fileSplitterFetch.nStartPos); LU7ia[T  
output.writeLong(fileSplitterFetch.nEndPos); \8KAK3i'  
} 0xSWoz[i6~  
output.close(); ' )0eB:  
} 2!}:h5  
catch(IOException e){e.printStackTrace ();} ytWTJ>L  
catch(Exception e){e.printStackTrace ();} M6j!_0j  
} S4salpz  
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//读取保存的下载信息（文件指针位置） cnm*&1EzV  
private void read_nPos() <r8sZrY  
{ kn^?.^dVX  
try{ aw3 oG?3I  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,>AA2@6zMT  
int nCount = input.readInt(); GY%2
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nStartPos = new long[nCount]; >" z$p@7  
nEndPos = new long[nCount]; :vsF4  
for(int i=0;i<nStartPos.length;i++) bg =<)s  
{ PQ#zF&gL9t  
nStartPos = input.readLong(); ~"Q24I  
nEndPos = input.readLong(); zL%ruWNG  
} MYmH
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input.close(); )6t=Bel  
} 8B*XXFy\  
catch(IOException e){e.printStackTrace ();} u>K(m))5W3  
catch(Exception e){e.printStackTrace ();} Im<i.a <`  
} f3p)Q<H>`(  
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private void processErrorCode(int nErrorCode) jNC@b>E?~  
{ ~8j4IO(  
System.err.println("Error Code : " + nErrorCode); v J_1VW  
} =B/Ac0Y  
03!!# 5iJ  
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//停止文件下载
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public void siteStop() 
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{ dw"Tv~  
bStop = true; TTfU(w%&P  
for(int i=0;i<nStartPos.length;i++) GY3g`M   
fileSplitterFetch.splitterStop(); ZQVr]/W^r  
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} |)4aIa  
} RyN}Gz/YN  
//负责部分文件的抓取 FUD M]:XQ  
**FileSplitterFetch.java Y\e8oIYu7  
*/ Q!T+Jc9N  
package NetFox; G<MX94?  
v5/2-<6x  
"Q[rM1R  
import java.io.*; u> @Yoyc  
import java.net.*; KiaQ^[/q  
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public class FileSplitterFetch extends Thread { *oW^P~m/  
s (hJ *
  
 hb,G'IU  
String sURL; //File URL ,~TV/l<  
long nStartPos; //File Snippet Start Position 3lw8%QD>  
long nEndPos; //File Snippet End Position `El)uTnuZ[  
int nThreadID; //Thread's ID T+q3]&  
boolean bDownOver = false; //Downing is over H;=JqD8`  
boolean bStop = false; //Stop identical mZgYR~  
FileAccessI fileAccessI = null; //File Access interface Xh[02iL-  
7R{(\s\9:  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ]i@
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{ kzb%=
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this.sURL = sURL; ^=1:!'*3D  
this.nStartPos = nStart; 7/UdE:~]*=  
this.nEndPos = nEnd; ITmW/Im5  
nThreadID = id; (v2.8zrJ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 U~}cib5W5  
} (TF;+FRW  
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$.g)%#h:  
public void run() +
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{ #6'+e35^8  
while(nStartPos < nEndPos && !bStop) iDdmr32E  
{ =a]B#uUn  
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try{ t#eTn";  
URL url = new URL(sURL); KsG>,# Q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); sZ7RiH+I  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,RYahu  
String sProperty = "bytes="+nStartPos+"-";
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httpConnection.setRequestProperty("RANGE",sProperty); EXz{Pqz  
Utility.log(sProperty); h88IP:bo  
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InputStream input = httpConnection.getInputStream(); 8A,="YIt  
//logResponseHead(httpConnection); x$WdW+glZ-  
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byte[] b = new byte[1024]; MB#KLTwnT  
int nRead; MF}}o0P  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) C>0='@LB@r  
{ 'C")X  
nStartPos += fileAccessI.write(b,0,nRead); l0sBXs`3b  
//if(nThreadID == 1) /Sn>{ &  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Qk_Mx"  
} |Ox!tvyr  
~|!f6=  
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Utility.log("Thread " + nThreadID + " is over!"); giNyD4uO  
bDownOver = true; ZBf9Upg  
//nPos = fileAccessI.write (b,0,nRead); *9?T?S|^$F  
} -AX[vTB  
catch(Exception e){e.printStackTrace ();} bpv?$j-j  
} km[PbC  
} q*36/I  
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\.AI;^)X@]  
//打印回应的头信息 L[LgQ7esQ  
public void logResponseHead(HttpURLConnection con) -y1t;yU.L  
{ Z,ZebS@yG  
for(int i=1;;i++) #2U4}#Mi  
{ ]di9dLT  
String header=con.getHeaderFieldKey(i); \~{b;$N}  
if(header!=null) wRLj>
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); Hrdz1:#6,  
Utility.log(header+" : "+con.getHeaderField(header)); aN}l&4d  
else xn`<g|"#  
break; 1$^=M[v  
} <Ky6|&!  
} J@4,@+X  
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public void splitterStop() xSal=a;k  
{ :87HXz6]jS  
bStop = true; ,2y" \_  
} UB7H`)C}  
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Q  
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} IY=CTFQ8lm  
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/* ~?x `f+  
**FileAccess.java RE?j)$y?`  
*//文件访问(定位，写) 4t<l9Ilp  
package NetFox; G"'[dL)N>  
import java.io.*; HsQ\xQ"k!  
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:: 2pDtMS  
public class FileAccessI implements Serializable{ )b_ GKA `  
::Nhs/B/  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 7Hm/g  
RandomAccessFile oSavedFile; `Y5{opG7-  
long nPos; a|s64+  
#ivN-WKCl  
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public FileAccessI() throws IOException k.dQ;v}  
{ IxxA8[^V  
this("",0); @N'0:0Nb_  
} {q}#  Sq  
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ly)b=ph&  
public FileAccessI(String sName,long nPos) throws IOException "~uo4n~H  
{ G^ 2a<?Di  
oSavedFile = new RandomAccessFile(sName,"rw"); wV,l }Xb-  
this.nPos = nPos; a!!>}e>Cj*  
oSavedFile.seek(nPos); nGdEJ  
} XJ.ERLR.  
.bT|:Q~@{  
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public synchronized int write(byte[] b,int nStart,int nLen) =%Yw;%0)Y  
{ YhzDi>hob  
int n = -1; w=txSF&Qr  
try{ '/@]V  
oSavedFile.write(b,nStart,nLen); t;~H6  
n = nLen; =rrbS8To=  
} fcC?1M[BP~  
catch(IOException e) >[U.P)7;  
{ ny,a5zEnF  
e.printStackTrace (); ;J)8#
|  
} 7rdPA9  
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return n; vG7aT  
} ^z^ UFW  
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} j
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H:DTvv8e{  
/* LE"t'R  
**SiteInfoBean.java Y.<&phv  
*/ p^s k?E  
package NetFox; )L%i"=<Bdy  
&>Ko}?w  
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public class SiteInfoBean { mOUIGlv  
GG}(*pOr  
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private String sSiteURL; //Site's URL #78P_{#!  
private String sFilePath; //Saved File's Path s|1BqoE  
private String sFileName; //Saved File's Name k$hNibpkt  
private int nSplitter; //Count of Splited Downloading File ;{Sgv^A  
e0#/3$\aSV  
p=U/l#xO  
public SiteInfoBean() VS:UVe  
{//nSplitter的缺省值为5 cVR3_e{&H  
//default value of nSplitter is 5 =>0+BD  
this("","","",5); #]@<YKoV{  
} <Rl:=(]i~  
<KFE.\*Z4  
*F
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) LQnkpy3A  
{ Ifc}=:nr  
sSiteURL= sURL; l{{wrU`  
sFilePath = sPath; SnhB$DG  
sFileName = sName; RRNoX}  
this.nSplitter = nSpiltter; Q
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/cy'% .!  
iuX82z`  
} CulU?-[i  
% 1+\N  
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public String getSSiteURL() v%e-vl  
{ P`^{dH$P  
return sSiteURL; 4RH'G
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} eDm~B(G$  
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f4s^$Q{Q  
public void setSSiteURL(String value) =!G3YZ  
{ tv)U 7K0  
sSiteURL = value; -bamNw>|  
} MBbycI,  
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b,
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public String getSFilePath() M=n_;3,o  
{ 9\/T #EP  
return sFilePath; *hHy>(*  
} ,u^S(vxyz  
z_dorDF8`>  
s{-`y`JP  
public void setSFilePath(String value) aN.t) DG}J  
{ 5K;vdwSB  
sFilePath = value; L29,Y=n@  
} Vs1j9P|G  
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public String getSFileName() OZF^w[ `w  
{ j;tT SNF  
return sFileName; P}%0YJ$6  
} J{gqm  
Sd3KY9,  
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public void setSFileName(String value) u#8J`%g  
{ b"ypS7 _  
sFileName = value; n.{+\M6k  
} )U`"3R  
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public int getNSplitter() 0x}8}  
{ FTy`#*7Ul  
return nSplitter; x9#>0 4s  
} +$#YW5wy  
'8NKrI  
1@nGD<,.  
public void setNSplitter(int nCount) %`%xD>![  
{ _jw A_  
nSplitter = nCount; {(7D=\eU  
} uv++Kj!  
} 3dnL\AqC  
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|S5N$[  
/* 9})!~r;|  
**Utility.java 41<.e`{  
*/ zfE;)K^"  
package NetFox; aW8Bx\q  
?-g=Rfpag  
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public class Utility { Ge+&C RhyX  
ZDZPJp,  
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public Utility() $X%GzrN  
{ 1n! JfsU  
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} .,:700n+^  
&z-f,`yG  
//线程睡眠 }b+tD3+  
public static void sleep(int nSecond) {4Q4aL(  
{ TqNEU<S/t  
try{ yA%(!v5UT  
Thread.sleep(nSecond); EO'[AU%~  
} vgzNT4o  
catch(Exception e) U9;C#9E  
{ bA-=au?o5  
e.printStackTrace (); '#SacJ\L7  
} Q{Gi**<  
} #,O<E@E  
;T}#-`O_Im  
//日志 k--.g(
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public static void log(String sMsg) 0px@3/  
{ =KwG;25hX  
System.err.println(sMsg); 30Nya$$A=  
} J!,5HJh1  
]6{G;f$  
29g("(}TK  
public static void log(int sMsg) I"E5XVC);  
{ NDhHU#Q9  
System.err.println(sMsg); Wig
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} >JFAE5tj&2  
} ^f{+p*i}:  
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}%EQ  
/* 93%U;0w[Nw  
**TestMethod.java M:OY8=V  
*/ \xk`o5/{  
package NetFox; dL<okw  
>9D=PnHnD  
1Y410-.3w{  
public class TestMethod { g2 uc+p  
x%ZjGDFm  
"sz)~Q'W5  
public TestMethod() 8#
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{ ///xx/weblogic60b2_win.exe rr2'bf<]  
try{ H~+D2A  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >R/^|hnJ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ARW|wXhyf  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -^8gZk/(W  
fileFetch.start(); t&u,Od  
} OvU]|4h  
catch(Exception e){e.printStackTrace ();} -IJt( X|  

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} KcVCA   
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public static void main(String[] args) pi? q<p%  
{ 8^;[c  
new TestMethod(); )`Tny]M  
} )Y@  
} ^;GJ7y&,d  
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