http断点续传简单实现（java)

/* ,Vq$>T@z  
**SiteFileFetch.java F'|K>!H  
*/ F^/KD<cgK  
package NetFox; 'o)Y!VYnJF  
import java.io.*; s[8M$YBf  
import java.net.*; [s$x"Ex  
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public class SiteFileFetch extends Thread { uD(C jHM>  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 8Ygf@*9L4  
long[] nStartPos; //开始位置 ^1~lnD~0  
long[] nEndPos; //结束位置 |Ogh-<|<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 6fw7\u  
long nFileLength; //文件长度 Xps \+l%i  
boolean bFirst = true; //是否第一次取文件 Aa_@&e  
boolean bStop = false; //停止标志 8o+:|V~X  
File tmpFile; //文件下载的临时信息 `^#4okg]  
DataOutputStream output; //输出到文件的输出流 ;`/a. /bc  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） CK
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public SiteFileFetch(SiteInfoBean bean) throws IOException DTH}=r-  
{ `Kg!aN  
siteInfoBean = bean; I(AlRh  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); z2{y<a9;?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); [>mH  
if(tmpFile.exists ()) $}vzBuWHwN  
{ ]&H"EHC<$  
bFirst = false; mS[``$Z\!  
read_nPos(); eH7x>[lH.  
} x2t&Wpvt  
else Q>Klkd5(  
{ bvJ@H Z$  
nStartPos = new long[bean.getNSplitter()]; C-S>'\|8  
nEndPos = new long[bean.getNSplitter()]; |pS]zD  
} Ep
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} &k,DAx`rN;  
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public void run() l
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{ 9#7W+9  
//获得文件长度 L3HC-  
//分割文件 z/"*-+j  
//实例FileSplitterFetch ~b
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//启动FileSplitterFetch线程 (/<Nh7C1c  
//等待子线程返回 xi{r-D8Z  
try{ , @UO
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if(bFirst) n_; s2,2r  
{ *]HnFP  
nFileLength = getFileSize(); L!*+:L DL  
if(nFileLength == -1) $adZ|Q\  
{ y>w;'
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System.err.println("File Length is not known!"); E"VFBKB  
} VQqBo~  
else if(nFileLength == -2) g(tVghHxt$  
{ >w<w*pC  
System.err.println("File is not access!"); +@^);b6  
} pD({"A.x9z  
else _b%)  
{ L$3lsu!4n  
for(int i=0;i<nStartPos.length;i++) d2Q*1Q@u  
{ uarfH]T{  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); P~{8L.w!>W  
} 5C1EdQ4S0  
for(int i=0;i<nEndPos.length-1;i++) {aUTTEu  
{ -GFZFi  
nEndPos = nStartPos[i+1]; v]{UH{6  
} >nSt<e  
nEndPos[nEndPos.length-1] = nFileLength; tXtNK2-1  
} \\\8{jq  
} B2j1GJEO  
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//启动子线程 O%kUj&h^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; hm73Zy
 
for(int i=0;i<nStartPos.length;i++) -MS#YcsV  
{ ="YGR:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :6lvX$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {>1FZsR49t  
nStartPos,nEndPos,i); exhU!p8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .+u b\  
fileSplitterFetch.start(); T#-;>@a}  
} I)'bf/6?  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), A/<u>cCW  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); -%"PqA/1zj  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", b*?u+
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nEndPos = " + nFileLength); ~i;{+j6Ho!  
// fileSplitterFetch[nPos.length-1].start(); P!|Z%H  
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,J|,wNDU!K  
//等待子线程结束 \PE;R.v_:  
//int count = 0; i$E [@  
//是否结束while循环 =|agW.l  
boolean breakWhile = false; =p'+kS+  
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while(!bStop) /jGBQ-X  
{ S/5QK(XLC)  
write_nPos(); ).5X  
Utility.sleep(500); C*
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breakWhile = true; D8Fi{?A#FV  
;_(f(8BO   
2; ^ME\  
for(int i=0;i<nStartPos.length;i++) Os"('@jd>  
{ %)r ~GCd  
if(!fileSplitterFetch.bDownOver) +\Vm t[v  
{ #; ?3kuq(  
breakWhile = false; ~+dps i  
break; m]2xOR_  
} ,_3hbT8Q  
} O6;"cUv  
if(breakWhile) _f[Q\gK  
break; R7bG!1SHl  
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//count++; sE"s!s/  
//if(count>4) sApix=Lr  
// siteStop(); G
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} {]^Ixm-,f  
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System.err.println("文件下载结束！"); Z4VFfGCTL  
} MoIh=rw  
catch(Exception e){e.printStackTrace ();} >7>I1  
} ]Btkoad  
A;TP~xq\  
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//获得文件长度 |u&cN-}C d  
public long getFileSize() `$T$483/  
{ o <q*3L5  
int nFileLength = -1; I/dy^5@F  
try{ [%P#ieD4  
URL url = new URL(siteInfoBean.getSSiteURL()); @RoZd?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D4=*yP
  
httpConnection.setRequestProperty("User-Agent","NetFox"); IP62|~Ap  
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.9jKD*U|  
int responseCode=httpConnection.getResponseCode(); _VrY7Mz:r  
if(responseCode>=400) 75^6?#GS  
{ n<ZPWlJ  
processErrorCode(responseCode); y}odTeq  
return -2; //-2 represent access is error ^dQ{vL@9b9  
} Gnkar[oa&  
[qYr~:`-[  
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String sHeader; %nZ
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for(int i=1;;i++) xVm-4gB  
{ & LE5'.s  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); j_Szw w-  
//Utility.log(in.readLine()); K;?D^n.  
sHeader=httpConnection.getHeaderFieldKey(i);  ?%,NOX  
if(sHeader!=null) [xMa^A>p  
{ <)VgGjZ-H  
if(sHeader.equals("Content-Length")) 6Z2,:j;  
{ ZitM<Qi&y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); EApKN@<"  
break; @+u>rS|IB  
} O*EV~{K  
} #oUNF0L@6  
else Y=Vbs x  
break; XjX  
} </h^%mnd  
} -pC8
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catch(IOException e){e.printStackTrace ();} t'qYM5  
catch(Exception e){e.printStackTrace ();} [,zq  
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Utility.log(nFileLength); j|eA*UE  
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return nFileLength; hx;f/EPx  
} gAqK)@8-  
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+{J8,^z#  
//保存下载信息（文件指针位置） ud1M-lY\U  
private void write_nPos() yK~=6^M  
{ <wH+\  
try{ sibYJKOy  
output = new DataOutputStream(new FileOutputStream(tmpFile)); hp\&g2_S0W  
output.writeInt(nStartPos.length); zG!nqSDG  
for(int i=0;i<nStartPos.length;i++)
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{ .HqFdsm  
// output.writeLong(nPos); u;#]eUk9}  
output.writeLong(fileSplitterFetch.nStartPos); <xOv8IQ|  
output.writeLong(fileSplitterFetch.nEndPos); bx@l6bpQ  
} !vnQ;g5  
output.close(); t}EMX9SQ  
} x%{]'z  
catch(IOException e){e.printStackTrace ();} v3tJtb^'!  
catch(Exception e){e.printStackTrace ();} 6cQgp]%  
} :6^7l/p  
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//读取保存的下载信息（文件指针位置） }pc9uvmIJ  
private void read_nPos() @ZKf3,J0  
{ jmok]-pC  
try{ sV^:
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~E<2gMKjO  
int nCount = input.readInt(); H}@:Br
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nStartPos = new long[nCount]; cTqkM@S  
nEndPos = new long[nCount]; GK(CuwJe  
for(int i=0;i<nStartPos.length;i++) RaZ>.5 D  
{ e|~MJu+1  
nStartPos = input.readLong(); k4TWfl^}9  
nEndPos = input.readLong(); !xM5 A[f  
} '`];=QY9pg  
input.close(); @[$_cGR7  
} p6VD*PT$&  
catch(IOException e){e.printStackTrace ();} gT+/nSrLV  
catch(Exception e){e.printStackTrace ();} wBPo{  
} 2|1fb-AR  
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private void processErrorCode(int nErrorCode) x3@-E  
{  O
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System.err.println("Error Code : " + nErrorCode); {K(mfTqm  
} a"8[,A3
 
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|(7}0]BP0  
//停止文件下载 6CJMQi,kn  
public void siteStop() ngY%T5-  
{ U=>S|>daR  
bStop = true; /--p#Gh'  
for(int i=0;i<nStartPos.length;i++) X/!_>@`7?  
fileSplitterFetch.splitterStop(); J~YT~D2L  
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} 1uF$$E6[  
} \& JZ >h  
//负责部分文件的抓取 0X$mT:=9  
**FileSplitterFetch.java Tc2.ciU  
*/ 7#8Gn=g  
package NetFox; nHK(3Z4G  
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import java.io.*; ^l &lwSRVt  
import java.net.*; Sb.8d]DW  
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public class FileSplitterFetch extends Thread { Iq$| ?MH  
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String sURL; //File URL lU WXXuO]  
long nStartPos; //File Snippet Start Position @sXFu[!U  
long nEndPos; //File Snippet End Position Ts iJK  
int nThreadID; //Thread's ID *4,Q9K_  
boolean bDownOver = false; //Downing is over Vns3859$8  
boolean bStop = false; //Stop identical ]5!3|UYS  
FileAccessI fileAccessI = null; //File Access interface [K{{P|(q  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException MDMd$]CW  
{ x`CjFaE~F  
this.sURL = sURL; s.3"2waZ=T  
this.nStartPos = nStart; _0H oJ  
this.nEndPos = nEnd; Ik G&  
nThreadID = id;  56.!L  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +ikSa8)*i  
} V>6klA}o
 
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public void run() 1HJ: ?]  
{ }\4yU=JPK  
while(nStartPos < nEndPos && !bStop) \i.]
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{ =?
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try{ I8H3*DE  
URL url = new URL(sURL); W/'1ftn?D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l1KMEGmG  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9#8vPjXW}.  
String sProperty = "bytes="+nStartPos+"-"; y:G%p3h)[  
httpConnection.setRequestProperty("RANGE",sProperty); +NlnK6T/  
Utility.log(sProperty); CTMC78=9}  
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InputStream input = httpConnection.getInputStream(); #~0Nk6*u  
//logResponseHead(httpConnection); lu=a e<M  
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byte[] b = new byte[1024]; %9-^,og  
int nRead; #UGSn:D<i  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 6<&~R3dQ  
{ $4bc!  
nStartPos += fileAccessI.write(b,0,nRead); ?kjQ_K  
//if(nThreadID == 1) !Tzo&G  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O&!R7T  
} B,b8\\^k|  
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Utility.log("Thread " + nThreadID + " is over!"); n 0!8)Sth  
bDownOver = true; {C |R@S  
//nPos = fileAccessI.write (b,0,nRead); x&B&lFmo8  
} y-<
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catch(Exception e){e.printStackTrace ();} RhWQ:l]  
} m8n)sw,,  
} C'R9Nn'  
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//打印回应的头信息 @SfQbM##%  
public void logResponseHead(HttpURLConnection con) Xv1vq -cM  
{ .Fb#j+Lq  
for(int i=1;;i++) '-wmY?ZFxy  
{ ]545:)Q1  
String header=con.getHeaderFieldKey(i); 2 6#p,P  
if(header!=null) Ak[X`e T  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Dka,v  
Utility.log(header+" : "+con.getHeaderField(header)); v9(5HY  
else ^O|fw?,  
break; ~${~To8$CW  
} 0C4eer+D  
} la[pA  
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public void splitterStop() ZP";B^J  
{ IQ&PPC  
bStop = true; _8G w Mj  
} s8-RXEPb  
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} xG!~TQ  
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/* }s,NM%oI  
**FileAccess.java )KZMRAT-  
*//文件访问(定位，写) 8eqTA8$?  
package NetFox; #j2kT  
import java.io.*; SZGR9/*^  
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8
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public class FileAccessI implements Serializable{ @$ 7 GrT  
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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 zPnb_[YF  
RandomAccessFile oSavedFile; Y0(4]X \ey  
long nPos; e!6yxL*[@[  
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public FileAccessI() throws IOException ixA.b#!1  
{ T"xJY#)}  
this("",0); XG|N$~N+2  
} Gz&}OO  
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public FileAccessI(String sName,long nPos) throws IOException I>?oVY6M@u  
{ (zsG!v  
oSavedFile = new RandomAccessFile(sName,"rw"); ^J]&($-  
this.nPos = nPos; ;6/WjUDw<|  
oSavedFile.seek(nPos); *)K\&h<{  
} _}R9!R0O  
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public synchronized int write(byte[] b,int nStart,int nLen) Wt/;iq"  
{ "Z&.m..gc  
int n = -1; pGD@R=8  
try{ <0d2{RQ;  
oSavedFile.write(b,nStart,nLen); ,X4b~)  
n = nLen; 6R45+<.  
} +q&Hj|;8r  
catch(IOException e) ` <1Wf  
{ u1meysa{0  
e.printStackTrace (); &n
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} 4r(0+SO  
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return n; Mj;V.Y  
} C*mVM!D);!  
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} c)#P}Ai  
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/* {KgA V  
**SiteInfoBean.java [v~,|N>w  
*/ >NUbk9}J4  
package NetFox; 6qT@M0)i  
]s=|+tz\V  
9JFN8Gf*)  
public class SiteInfoBean { C6)YZC  
M!,H0(@G  
`#$}P;W  
private String sSiteURL; //Site's URL 9[/0  
private String sFilePath; //Saved File's Path Om*QN]lGq  
private String sFileName; //Saved File's Name ZPZh6^cc  
private int nSplitter; //Count of Splited Downloading File 0j@mzd2  
E7$&:xqx  
WJq>%<#  
public SiteInfoBean() brA#p>4]Wf  
{//nSplitter的缺省值为5 j4IVIj@$`  
//default value of nSplitter is 5 &D3]O9a0;  
this("","","",5); E`TZ:W]r,  
} ,' k?rQ  
h  /  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) P}4&J ^  
{
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sSiteURL= sURL; vzSb(  
sFilePath = sPath; ZN8j})lE  
sFileName = sName; y`RzcXblIZ  
this.nSplitter = nSpiltter; /V,xSK9.&  
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} @JGmOwZ  
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public String getSSiteURL() J2qsZ  
{ _9>,9aL  
return sSiteURL; ins(RWO  
} RQE]=N  
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public void setSSiteURL(String value) <%^/uS  
{ D=ej%]@iw  
sSiteURL = value; %* 0GEfl/  
} 3A,N1OXG  
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public String getSFilePath() 1]If< <  
{ xVPSL#>
 
return sFilePath; 0$|VkMq(  
} Vq3NjN!+5  
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public void setSFilePath(String value) A"S"La%"  
{ !`_f  
sFilePath = value; v:SHaUS  
} w"0$cL3  
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public String getSFileName() -o+t
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{ o'lG9ePM|  
return sFileName; \ZRII<k5)  
} [6TI_U~  
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public void setSFileName(String value) CRo'r/G  
{ 21OfTV-+3  
sFileName = value; f
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} <l1/lm<#  
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public int getNSplitter() |6d:k~p  
{ I0Do%  
return nSplitter; d*+}_EV)Y3  
} &3/`cl[+  
s>;"bzzq  
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public void setNSplitter(int nCount) ^:?z7m  
{ Kj?)]Z4  
nSplitter = nCount; IG
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} xLIyh7$t  
} HV!P]82Pa  
`_vPElQXZ#  
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/* xFUD9TM  
**Utility.java 9>+>s ?IgK  
*/ hak#Iz0[C  
package NetFox; >kAJS??  
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>]}VD "\  
public class Utility { `*CoVx~fk  
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j 1'H|4  
public Utility() W=2.0QmW  
{ Ew}G
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7# 'j>]  
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} F-Z>WC{+  
.aZB?MW  
//线程睡眠 Nt+UL/1]  
public static void sleep(int nSecond) ,hK =x  
{ $_ $%L0)5  
try{ Ql7opl,  
Thread.sleep(nSecond); ^?%ThPo_  
} Y\!:/h]E&  
catch(Exception e) 0jpyc  
{ D622:Y886  
e.printStackTrace (); /x-tl)(s=  
} ,[m4+6G5  
} #oGvxc7  
hQSJt[8My  
//日志 "z.!h(Eq  
public static void log(String sMsg) ,^xsdqpe  
{ VyU!r* o  
System.err.println(sMsg); u@wQ )^  
} }xrrHp  
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# 9f 4{=\  
public static void log(int sMsg) >fR#U"KPAB  
{ u*;53 43  
System.err.println(sMsg); B7ys`eiB5C  
} RDG,f/L2  
} A&'HlI%J  
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;+qP
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/* Q!%CU8!`&  
**TestMethod.java ,TO&KO1;&  
*/ = &aD!nTx  
package NetFox; sEfGf.  
`V ++})5v  
1/qiE{NW  
public class TestMethod { w_J`29uc  
RZE:WE;5  
 K[TMTn  
public TestMethod() ;v+CQx  
{ ///xx/weblogic60b2_win.exe l:+pO{7L  
try{ [76mgj!K  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ")M.p_b[Z=  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); /C8(cVNZ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "/XS3sv"s  
fileFetch.start(); Js#c9l{{  
} J&:0ytG  
catch(Exception e){e.printStackTrace ();} |V~P6o(/  
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} "AVj]jR  
S(-=I!.G{  
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public static void main(String[] args) IA!ixabG  
{ 'Jl.fN  
new TestMethod(); |)JoxqR  
} G7/LYTT)  
} &Y=NUDt_  
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