http断点续传简单实现（java)

/* :1aL ?  
**SiteFileFetch.java cxP
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*/ vq'k|_Qi=  
package NetFox; =/9^, 6Q(  
import java.io.*; Fx#jV\''s  
import java.net.*; p*qPcuAA  
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public class SiteFileFetch extends Thread { h*l&RR:i  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 07_oP(;jT  
long[] nStartPos; //开始位置 ^DAu5|--R  
long[] nEndPos; //结束位置 mG2'Y)Sz  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 E4oz|2!m  
long nFileLength; //文件长度 Z"v<0]rN  
boolean bFirst = true; //是否第一次取文件 C/@LZ OEL  
boolean bStop = false; //停止标志 I.jZ wW!r  
File tmpFile; //文件下载的临时信息 8l+H"M&|  
DataOutputStream output; //输出到文件的输出流 %s=Dj2+  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） .#w6%c@  
public SiteFileFetch(SiteInfoBean bean) throws IOException lK(Fg  
{ e XV@.  
siteInfoBean = bean; 7+,vTsCd  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); -n))*.V  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Z~u9VYi!  
if(tmpFile.exists ()) Gt-UJ-RR y  
{ $:bih4@>  
bFirst = false; a)s;dp}T%  
read_nPos(); mY-hN|  
} eph)=F$  
else 1|| nR4yK  
{ vF={9G  
nStartPos = new long[bean.getNSplitter()]; m5c&&v6%"b  
nEndPos = new long[bean.getNSplitter()]; pbBoy+.>  
} +
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} = [@)R!3H  
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public void run() w=_Jc8/.  
{ 4 J^Q]-Z  
//获得文件长度 i!H!;z#  
//分割文件 I-@?guZ r  
//实例FileSplitterFetch Va<eusl  
//启动FileSplitterFetch线程 <iLM{@lZvJ  
//等待子线程返回 5>_5]t {  
try{ WNX5iwm  
if(bFirst)
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{ ;`j/D@H  
nFileLength = getFileSize(); X
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if(nFileLength == -1) 1y"3  
{ ^Z,q$Gp~P  
System.err.println("File Length is not known!"); @4GA^h  
} ][@F  
else if(nFileLength == -2) <z)m%*lvU  
{ g
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System.err.println("File is not access!"); v
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} @w9{5D4  
else )P Jw+5  
{ |\9TvN^$`  
for(int i=0;i<nStartPos.length;i++) onei4c>@  
{ n
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); JMa3btLy(  
} :}}%#/nd  
for(int i=0;i<nEndPos.length-1;i++) iz^qR={bW  
{ IyUdZ,ba  
nEndPos = nStartPos[i+1]; Zj9c9  
} C*kK)6v`  
nEndPos[nEndPos.length-1] = nFileLength; Kuw^qX"  
} C"V%#
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} [3>GGX[Ic  
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//启动子线程 7(k^a)~PL  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; sfD5!Z9#1  
for(int i=0;i<nStartPos.length;i++) Kx`/\u=/  
{ oOU
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Pcd *">v  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), WrGK
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nStartPos,nEndPos,i); jA(vTR.`  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); gBw^,)Q{0Y  
fileSplitterFetch.start(); WCq /c6 D  
} b~Y%gC)FR  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4vZ4/#(x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); N3A<:%s  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", LEWhb!U  
nEndPos = " + nFileLength); #;VA5<M8  
// fileSplitterFetch[nPos.length-1].start(); /Ft:ffR|R  
|i%2%V#  
^_5|BT@  
//等待子线程结束 &Z("D7
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//int count = 0; EMvHFu   
//是否结束while循环 ,XKCz ]8V  
boolean breakWhile = false; sH#X0fG  
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while(!bStop) $K}DB N; 4  
{ DT(d@upH  
write_nPos(); }^ FulsC  
Utility.sleep(500); l$Gl'R>>*  
breakWhile = true; o+O}Te  
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for(int i=0;i<nStartPos.length;i++) 5p"BD'^:  
{ Zk-~ar  
if(!fileSplitterFetch.bDownOver) 0"WDH)7hJ  
{ P.\nLE J=  
breakWhile = false; e79KbLV  
break; LO%!Z,}   
} r`'y?Bra;  
} R=)55qu  
if(breakWhile) wD\ZOn_J  
break; Kyg=$^{>G  
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//count++; PH3 >9/H  
//if(count>4) b0<o  
// siteStop(); U^lW@u?:  
} @J'YV{]  
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System.err.println("文件下载结束！"); q1VH5'p@  
} 77 r(*.O|  
catch(Exception e){e.printStackTrace ();} vG.9H_&  
} N#xG3zZl|N  
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//获得文件长度 NaUr!s  
public long getFileSize() L{{CAB!  
{ d3Di/Iej  
int nFileLength = -1; )
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try{ T Eu'*>g  
URL url = new URL(siteInfoBean.getSSiteURL()); /1w2ehE<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :\ QUs}  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1QqHF$S  
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int responseCode=httpConnection.getResponseCode(); Z=S>0|`R  
if(responseCode>=400) ;az5ZsvN D  
{ xG2+(f#C1  
processErrorCode(responseCode); _D7]-3uC!  
return -2; //-2 represent access is error m#e3%150{  
} ^]C&tG0 !  
]88];?KS}  
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String sHeader; xJ8%<RR!t  
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for(int i=1;;i++) H6TD@kL9Wr  
{ v4/-b4ET  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ZAKeEm2A  
//Utility.log(in.readLine()); 6=hk=2]f  
sHeader=httpConnection.getHeaderFieldKey(i); RIn9(r  
if(sHeader!=null) FqFapRX66Z  
{ cgu~  
if(sHeader.equals("Content-Length")) h@{_duu  
{ GwU?wIIj^  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9O*_L:4o  
break; 8|?LN8rp  
} $(pF;_W  
} ; 0v>Rfa  
else | tQ
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break; fnKY1y]2+  
} :aLT0q!K  
} 6.1)IQkO  
catch(IOException e){e.printStackTrace ();} |Hr:S":9  
catch(Exception e){e.printStackTrace ();} po9 9 y-  
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Utility.log(nFileLength); R<ND=[}s  
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return nFileLength; F^$led1/F  
} MxQ?Sb%Gka  
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//保存下载信息（文件指针位置） Os%n{_#8  
private void write_nPos() qml2XJ>  
{ =DbY?Q<Q  
try{ `/&SxQB<  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Z;Rp+X  
output.writeInt(nStartPos.length); pv!oz2w1  
for(int i=0;i<nStartPos.length;i++) [%A4]QzWh  
{ `Pn[tuIO  
// output.writeLong(nPos); U:6W+p8  
output.writeLong(fileSplitterFetch.nStartPos);
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output.writeLong(fileSplitterFetch.nEndPos); d&8APe  
} tMx}*l|]  
output.close(); QYb33pN|  
} V&]DzjT/  
catch(IOException e){e.printStackTrace ();} |!SOG  
catch(Exception e){e.printStackTrace ();} I&|f'pn^<  
} |C%Pjl^YkV  
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//读取保存的下载信息（文件指针位置） qZEoiNH(Tj  
private void read_nPos() M6r^L6$N  
{ LK9g0_  
try{ $4FX(O0Q@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 8e~|.wOL  
int nCount = input.readInt(); s MN*RKer  
nStartPos = new long[nCount]; Lw7=+h)  
nEndPos = new long[nCount]; &ZHC-qMRK  
for(int i=0;i<nStartPos.length;i++) )}%O>%  
{ AdZ;j6#  
nStartPos = input.readLong(); s pLZ2]A  
nEndPos = input.readLong(); |WryBzZ>on  
} nwt C:*}  
input.close(); 1_'? JfY-  
} `IpA.| Y  
catch(IOException e){e.printStackTrace ();} IxR?'  
catch(Exception e){e.printStackTrace ();} ma$Prd  
} #3=P4FUz.  
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private void processErrorCode(int nErrorCode) %%ae^*[!n  
{ :1q4"tv|  
System.err.println("Error Code : " + nErrorCode); }U w&Ny  
} `~UZU@/x  
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. v@>JZC  
//停止文件下载 OX:O^ (-r,  
public void siteStop() D<i[LZd  
{ Fk;oE'"D  
bStop = true; )QagS.L{z  
for(int i=0;i<nStartPos.length;i++) 2g9G{~,@g  
fileSplitterFetch.splitterStop(); # {fTgq  
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} dUznxZB  
} V}o n|A  
//负责部分文件的抓取 ,fIe&zq  
**FileSplitterFetch.java M~*u;v
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*/ ~n')&u{  
package NetFox; IL/Yc1  
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import java.io.*; t&Os;x?To?  
import java.net.*; /y7M lU9  
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public class FileSplitterFetch extends Thread { ./j,
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String sURL; //File URL r,goRK.  
long nStartPos; //File Snippet Start Position Hd7,ZHj3^  
long nEndPos; //File Snippet End Position C9DJO:f.2y  
int nThreadID; //Thread's ID H2xeP%;$  
boolean bDownOver = false; //Downing is over o`zr>  
boolean bStop = false; //Stop identical I\?9+3 XnQ  
FileAccessI fileAccessI = null; //File Access interface . #Z+Z  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException qa(>wR"m
T  
{ ,6!rR,0  
this.sURL = sURL; I-]>d;4.  
this.nStartPos = nStart; *rZ^^`4R  
this.nEndPos = nEnd; ^ 5VK>  
nThreadID = id; GhY1k";  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 `u!l3VZ/4  
} , $Qo =  
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public void run() M}_i52  
{ Kz<@x`0   
while(nStartPos < nEndPos && !bStop) 8By,#T".  
{ &Lt[WT$  
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try{ E+"dq
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URL url = new URL(sURL); ._wkj  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]Fvm 7V  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5WqXo{S  
String sProperty = "bytes="+nStartPos+"-"; O
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httpConnection.setRequestProperty("RANGE",sProperty); 5G0
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Utility.log(sProperty); YI-O{U  
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InputStream input = httpConnection.getInputStream(); D47R  
//logResponseHead(httpConnection); #zrTY9m7  
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byte[] b = new byte[1024]; .*$
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int nRead; O9'x-A%  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ; UiwH  
{ ri C[lB  
nStartPos += fileAccessI.write(b,0,nRead); N4;7gSc"  
//if(nThreadID == 1) ]Mj/&b>"e  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Sp}D;7  
} vhvdKD  
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Utility.log("Thread " + nThreadID + " is over!"); gef6pfV  
bDownOver = true; -16K7yk  
//nPos = fileAccessI.write (b,0,nRead); 2eeQ@]Wj[Z  
} kVI#(uO  
catch(Exception e){e.printStackTrace ();} sC00un%  
} S~qZr  
} obK*rdg,  
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//打印回应的头信息 I9o6k?$K  
public void logResponseHead(HttpURLConnection con) %8a
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{ Y=Z1Tdxa|  
for(int i=1;;i++) 'tN25$=V&W  
{ iDl;!b&V.  
String header=con.getHeaderFieldKey(i);  I~,G  
if(header!=null) Vh3Ijn  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &Gm$:T'~  
Utility.log(header+" : "+con.getHeaderField(header)); +,:^5{9{  
else Rj~  
break; TUT][ =.=  
} ^1:U'jIXO  
} oIGrA-T}  
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public void splitterStop() #{r#;+  
{ e@@?AB$n(  
bStop = true; ,=(Z00#(  
} nI*/Mhx  
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} -K(fh#<6KO  
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/* r _,_5 @0e  
**FileAccess.java MyJ4><oG  
*//文件访问(定位，写) z|G9,:9  
package NetFox; OQ :dJe6
 
import java.io.*; oRN-xng  
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public class FileAccessI implements Serializable{ X.O
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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!:ITa  
RandomAccessFile oSavedFile; < `qRA]  
long nPos; UX`]k{Mz  
EG'[`<*h  
-]C

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public FileAccessI() throws IOException gw+9x<e  
{ 3qHQX?a  
this("",0); h9$ Fx  
}  "SN4*  
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public FileAccessI(String sName,long nPos) throws IOException 2y0J`!/)  
{ k)S.]!u&G  
oSavedFile = new RandomAccessFile(sName,"rw"); qZ@0]"h  
this.nPos = nPos; *fO3]+)d+  
oSavedFile.seek(nPos); 8T;IZ(s  
} n<Svwa}  
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public synchronized int write(byte[] b,int nStart,int nLen) u{&B^s)k.  
{ /9Q3iV$I]  
int n = -1; _|<d5TI  
try{ f#%JSV"7  
oSavedFile.write(b,nStart,nLen); Ap&)6g   
n = nLen; (-
7ZI"Ku  
} "_L?2ta  
catch(IOException e) 3[p_!eoW  
{ "Z,q?Fc  
e.printStackTrace (); rh2LGuo4m  
} <Y 4:'L6  
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return n; KHKS$D  
} CR4rDh8za  
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} 0m[dP  
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/* {hSGv
  
**SiteInfoBean.java {TSY|D2  
*/ Hyk'c't_O  
package NetFox; `znB7VQ0  
7&}P{<}o^  
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public class SiteInfoBean { jdut4 nFc  
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private String sSiteURL; //Site's URL BJjx|VA+  
private String sFilePath; //Saved File's Path @`u?bnx]e  
private String sFileName; //Saved File's Name F SMj  
private int nSplitter; //Count of Splited Downloading File 2H#N{>7  
_cJ[ FP1  
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public SiteInfoBean() qX:B4,|ck  
{//nSplitter的缺省值为5 dLh6:Gh8_I  
//default value of nSplitter is 5 U0B2WmT~Q  
this("","","",5);  ~m=EM;  
} ;uI~BV*3  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ucYkxi`x  
{ >X}{BDMb.  
sSiteURL= sURL;
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sFilePath = sPath; >G)qns9  
sFileName = sName; g9tu%cIkR  
this.nSplitter = nSpiltter; }F1s tDx  
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} ND]S(C"?  
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public String getSSiteURL() 64oxjF)  
{ Z_z#QX>=D  
return sSiteURL; :Z`4j  
} c,5n,i  
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"X1vZwK8N  
public void setSSiteURL(String value) ,TC~~EWq  
{ y>o>WN<q  
sSiteURL = value; $%qg"  
} E{^^^"z P  
9/TY\?U  
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public String getSFilePath() s3t!<9[m  
{ 4I~i)EKy6  
return sFilePath; M]_E  
} D5]{2z}k  
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public void setSFilePath(String value) m@qqVRn#)  
{ e1 a*'T$z  
sFilePath = value; 0Oxz3r%}r  
} CmC0k-%w  
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public String getSFileName() # mT]j""  
{ jz:gr=*z  
return sFileName; aiftlY  
} 3;/?q  
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2"/yEg*=  
public void setSFileName(String value) >9(i)e  
{ 2_pz3<,\  
sFileName = value; %`\]Y
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} A3UQJ  
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S ~|.&0"\  
public int getNSplitter() QlzQ]:dWC  
{ YdOUv|tZC  
return nSplitter; [%8@DC'  
} 'V!kL, 9ES  
zXre~b03ZS  
=HE m)  
public void setNSplitter(int nCount) `BT*,6a  
{ {yq8<?  
nSplitter = nCount; TbNGgjT  
} [&VxaJ("3  
} lizTRVBE  
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/* f!g<3X{=  
**Utility.java rihlae5Kz  
*/ {+=i?  
package NetFox; `SOhG?Zo  
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I4  
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^  
public class Utility { DP>mNE  
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public Utility() \3^Pjx  
{ I'IB_YRL4  
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} :kp0EiJ  
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//线程睡眠 ?)cJZ>$!w  
public static void sleep(int nSecond) ,L%p
  
{ @hT;Bo2G]  
try{ _i@x@:_l  
Thread.sleep(nSecond); 1q!sKoJ<  
} M {xie  
catch(Exception e) wItzcY1m  
{ hEOJb @:R  
e.printStackTrace (); r<(kLpOH%  
} E^syrEz  
} Ekf2NT  
v MWC(m  
//日志 "k
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public static void log(String sMsg) ~&~C#yjg1  
{ FOp_[rR   
System.err.println(sMsg); d| \#?W&  
} cdsQ3o  
&7F&}7*c  
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public static void log(int sMsg) z(UX't (q  
{ n4*'B*  
System.err.println(sMsg); -A@U0=o  
} m|dF30~A  
} rk|a'&  
C
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'#f?#(  
/* ~~dfpW_"  
**TestMethod.java IMR$x(g= F  
*/ nO [QcOf  
package NetFox; 6QptKXu7  
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s}!"a8hU`  
public class TestMethod { *2:Yf7rvI+  
*]9XDc]{j1  
4`0;^K.  
public TestMethod() +-k`x0v  
{ ///xx/weblogic60b2_win.exe /O"0L/hc^  
try{ gT7I9 (x!W  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); $y4M#yv  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); JOHp?3"4  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Bcm=G
""  
fileFetch.start(); %#Q #N,fw  
} 7eH@n<]Y2  
catch(Exception e){e.printStackTrace ();} /2'c>  
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} V,'FlU  
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public static void main(String[] args) B2"+Hwbk  
{ m-#d8sD2C  
new TestMethod(); Ko}7$2
^  
} &@Yoj%%  
} WFks|D:sB  
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