http断点续传简单实现（java)

/* h#bpog  
**SiteFileFetch.java 1KxtHLLU  
*/ B8'(3&)My  
package NetFox; MI[=,0`D  
import java.io.*; %v++Ac
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import java.net.*; @:DS/#!  
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public class SiteFileFetch extends Thread { Hl&]r'bK  
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SiteInfoBean siteInfoBean = null; //文件信息Bean l7 D/]&  
long[] nStartPos; //开始位置 m{gK<T  
long[] nEndPos; //结束位置 ;F@dN,Y  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 |N[SCk>Kj  
long nFileLength; //文件长度 &o/&T{t}  
boolean bFirst = true; //是否第一次取文件 :xd&V%u`  
boolean bStop = false; //停止标志 CORNN8=k  
File tmpFile; //文件下载的临时信息 !ViHC}:  
DataOutputStream output; //输出到文件的输出流 DvnK_Q!  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） zqAK|jbL  
public SiteFileFetch(SiteInfoBean bean) throws IOException ;2RCgX!'%  
{ Nzc1)t=  
siteInfoBean = bean; Z2B59,I  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]4@z.1Mr  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); yS/ovd  
if(tmpFile.exists ()) AX8;x1t^.  
{ m^_)aS  
bFirst = false; 'w.:I TJf  
read_nPos(); WPyd ^Y<  
} ee&QZVL>  
else KM(U-<<R  
{ {rOz[E9vm  
nStartPos = new long[bean.getNSplitter()]; f9u["e  
nEndPos = new long[bean.getNSplitter()]; "z^Ysvw&~  
} D00rO4~6D%  
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} cd}TDd(H%  
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public void run() a(Z" }m  
{ K@*m6)  
//获得文件长度 e,I-u'mLQs  
//分割文件 M:?eK [h  
//实例FileSplitterFetch M 0->  
//启动FileSplitterFetch线程 ?MeP<5\A  
//等待子线程返回 K1z"..(2J  
try{ f7OfN#I  
if(bFirst) fx.FHhVu  
{ UeE& 8{=d  
nFileLength = getFileSize(); 
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if(nFileLength == -1) ]@ETQ8QN  
{ ~PuPY:"  
System.err.println("File Length is not known!"); 4E3HY
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} 1`_Mc ]  
else if(nFileLength == -2) f%*-PW^*  
{ aI|)m8>)X  
System.err.println("File is not access!"); A@'):V8_%C  
} C bG"8F|4  
else >~J_9'gX6
 
{ 4)9X) Qx  
for(int i=0;i<nStartPos.length;i++) SVXey?A;CJ  
{ x#dJH9NR[  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); V6wYJ$]
 
} $K<jmEC@<  
for(int i=0;i<nEndPos.length-1;i++) $yaE!.Kc  
{ @c$mc  
nEndPos = nStartPos[i+1]; $.
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} T:cSv @G  
nEndPos[nEndPos.length-1] = nFileLength; 9L:v$4{LU  
} ;?inf`t  
} |c8p{)  
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//启动子线程 BY,%+>bc)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 
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for(int i=0;i<nStartPos.length;i++) !^q<)!9<EO  
{ mMT7`r;l  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -lSm:O@'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9'//_ A,  
nStartPos,nEndPos,i); `-ENKr]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); lu-VBV
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fileSplitterFetch.start(); 4KybN  
} f<|8NQ2y.  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #FaR?L![Y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !;CY @=  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -oF4mi8S  
nEndPos = " + nFileLength); shn`>=0.&  
// fileSplitterFetch[nPos.length-1].start(); mq'q@@:c  
6t]oSxN  
=#%e'\)a  
//等待子线程结束 aKCCFHq t!  
//int count = 0; WlZ
[9,:p1  
//是否结束while循环 ^r;}6  
boolean breakWhile = false; |
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7\{<AM?*  
while(!bStop) <#|3z8N2  
{ x6Z$lhZ  
write_nPos(); %q>gwq A  
Utility.sleep(500); {2Gp+
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breakWhile = true; +~FH'DsT  
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for(int i=0;i<nStartPos.length;i++) -ZihEyG?V  
{ :sT<<LtI-  
if(!fileSplitterFetch.bDownOver) z eIBB  
{ j?z(fs-  
breakWhile = false; Y,E:?  
break; AS;{O>}54  
} k )){1O  
} B u4N~0
 
if(breakWhile) *QLl jGe  
break; 4\sS  
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//count++; miN(a; Q2P  
//if(count>4) cW&OVNj  
// siteStop(); Za}91z"  
} TS3 00F  
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System.err.println("文件下载结束！"); :syR4A WM  
} \D}/tz5~B  
catch(Exception e){e.printStackTrace ();} c1n? @L  
} &]z2=\^e  
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//获得文件长度 ~=c
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public long getFileSize() 9pjk3a  
{ R~Xl(O  
int nFileLength = -1; wp*;F#:G  
try{ GB[W'QGiq  
URL url = new URL(siteInfoBean.getSSiteURL()); U}Hmzb  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); f$WO{J  
httpConnection.setRequestProperty("User-Agent","NetFox"); CtSAo\F  
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int responseCode=httpConnection.getResponseCode(); .+[[m$J  
if(responseCode>=400) ]m}>/2oSs  
{ f4w|  
processErrorCode(responseCode); >Xb]n_`  
return -2; //-2 represent access is error * rs_k/2(  
} !4z"a@$  
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String sHeader; 6'wP?=  
m&
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for(int i=1;;i++) +;>>c`{  
{ H9jj**W ;$  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); $\P!
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//Utility.log(in.readLine()); X)uT-Fy  
sHeader=httpConnection.getHeaderFieldKey(i); J-,T^Wv  
if(sHeader!=null) bq ~'jg^#  
{ l_}c[bAUu  
if(sHeader.equals("Content-Length")) c8}1-MKs_R  
{ vk#xCggK  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _wHqfj)  
break; p(x[zn+%Y  
} fwl RwH(  
} Pel3e ~?t  
else %HSoQ?qA  
break; aMj3ov8p  
} &'|bZms g  
} Bq$bxuhV  
catch(IOException e){e.printStackTrace ();} cc^V~-ph  
catch(Exception e){e.printStackTrace ();} OK2wxf  
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Utility.log(nFileLength); :W'1Q2  
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return nFileLength; =CqLZ$10  
} da2BQ;  
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g\jdR_/  
//保存下载信息（文件指针位置） !J6k\$r  
private void write_nPos() Crey}A/N  
{ 'vCFT(C-  
try{ b9\=NdyCY  
output = new DataOutputStream(new FileOutputStream(tmpFile)); lR-4"/1|y  
output.writeInt(nStartPos.length); 8`*`4m  
for(int i=0;i<nStartPos.length;i++) r
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{ isDr|g$S  
// output.writeLong(nPos); sjzZl*GSy  
output.writeLong(fileSplitterFetch.nStartPos);  kU#$  
output.writeLong(fileSplitterFetch.nEndPos); L:%h]-  
} 0,VbB7 z  
output.close(); thq(tK7  
} I/'jRM  
catch(IOException e){e.printStackTrace ();} 5B@&]-'~  
catch(Exception e){e.printStackTrace ();} G-;pMFP(?  
} s=KA(4p  
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//读取保存的下载信息（文件指针位置） LL:B H,[  
private void read_nPos() U:IQWlC  
{ 46$5f?Z  
try{ `Y'}\>.#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); UDxfS4yI  
int nCount = input.readInt(); 0gnr@9,X  
nStartPos = new long[nCount]; E7 7Au;TL  
nEndPos = new long[nCount]; (s\Nm_j  
for(int i=0;i<nStartPos.length;i++) L%=u&9DmU  
{ Qy9#(596  
nStartPos = input.readLong(); aA\v  
nEndPos = input.readLong(); t/nu/yz5E  
} /dtFB5Z"w  
input.close(); |qZ4h
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} hL&z"_
`  
catch(IOException e){e.printStackTrace ();} `+i<:,z-gs  
catch(Exception e){e.printStackTrace ();} $e0sa=/  
} HPu nNsA  
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private void processErrorCode(int nErrorCode) ;[%AeN5W  
{ R{Cj]:Ky  
System.err.println("Error Code : " + nErrorCode); c!6.D  
} 6&h,eQ!  
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//停止文件下载 +AXui|mn  
public void siteStop() y/ vE  
{ l? 7D
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bStop = true; w 8T#~Dc  
for(int i=0;i<nStartPos.length;i++) ~kF^0-JZY  
fileSplitterFetch.splitterStop(); *\-6p0~A  
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} 4fQ<A <2/  
} Z+FJ cvYx  
//负责部分文件的抓取 ".~,(
*  
**FileSplitterFetch.java KN_3]-+B  
*/ _@SC R%  
package NetFox; Un@dWf6'  
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import java.io.*; ~xkcQ{  
import java.net.*; t 8|i>(O  
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public class FileSplitterFetch extends Thread { 1H{JT op  
!CY:XQm  
F7x]BeTM  
String sURL; //File URL iTwb#Q=  
long nStartPos; //File Snippet Start Position =g UOHH  
long nEndPos; //File Snippet End Position :tdN#m6&  
int nThreadID; //Thread's ID yxik`vmH  
boolean bDownOver = false; //Downing is over f;x0Ho5C2  
boolean bStop = false; //Stop identical fX2sjfk  
FileAccessI fileAccessI = null; //File Access interface Xq@Bzya  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException f; w\k7 #  
{ lK 5@qG#  
this.sURL = sURL; )[+82~F  
this.nStartPos = nStart; _(l?gj  
this.nEndPos = nEnd; I() =Ufs5z  
nThreadID = id; |Bz1u|uc  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~G,_4}#"pM  
} <hvs{}TS  
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public void run() %D1 |0v8}  
{ +fS<YT  
while(nStartPos < nEndPos && !bStop) !mHMFwvS  
{ @<(4J   
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try{ '.EO+1{a  
URL url = new URL(sURL); U}@xMt8@l  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5C0![$W>  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~-R%m  
String sProperty = "bytes="+nStartPos+"-"; ~jC+6v  
httpConnection.setRequestProperty("RANGE",sProperty); @@JyCUd  
Utility.log(sProperty); `6$|d,m5  
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InputStream input = httpConnection.getInputStream(); `+z^#3l  
//logResponseHead(httpConnection); 0vETg'r  
is }>+&_  
] # VHx  
byte[] b = new byte[1024]; ?4A/?Z]ub  
int nRead; o?Aj6fNY?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) rk6K0TQ8  
{ U0gZf5;*  
nStartPos += fileAccessI.write(b,0,nRead); 4-~Z{#-  
//if(nThreadID == 1) eU\xOTl~<{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); JIhEkY  
} 84vd~Cf9  
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Utility.log("Thread " + nThreadID + " is over!"); K+pVRDRcs  
bDownOver = true; yQuL[#
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//nPos = fileAccessI.write (b,0,nRead); h2 KI  
} 6<2H 7'  
catch(Exception e){e.printStackTrace ();} 9w$m\nV  
} =:aJZ[UU<2  
} *,mI=1  
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//打印回应的头信息 8l_M 0F,  
public void logResponseHead(HttpURLConnection con) ')U~a  
{ 2]1u0-M5L  
for(int i=1;;i++) U.KQjBi  
{ rUpe  ;c  
String header=con.getHeaderFieldKey(i); CHsg2S  
if(header!=null) >!6|yk`GJ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); RWc<CQcL"  
Utility.log(header+" : "+con.getHeaderField(header)); #~!"`B?#*  
else < Hkq  
break; B2e"  
} /TyGZ@S>m  
} gs5(~YiT6  
,$0-I@*V  
} vmRm*8z  
public void splitterStop() |RFBhB/u  
{ odCt6Du  
bStop = true; MfP)Pk5  
} PD)"od  
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} &)Xc'RQ.C  
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/* OvtE)ul@  
**FileAccess.java DMM<,1  
*//文件访问(定位，写) 51SmoFbMz  
package NetFox; X*QS/\  
import java.io.*; qx t0Jr8  
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public class FileAccessI implements Serializable{ N% 4"9K  
GC{M"q|_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 V5w1ET  
RandomAccessFile oSavedFile; Nob(D'vSr  
long nPos; {drc}BL_  
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public FileAccessI() throws IOException X H-_tvB  
{ HeOdCr-PN  
this("",0); D5TDg\E  
} gcU*rml  
2yZr!Rb~*  
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public FileAccessI(String sName,long nPos) throws IOException "2l`XH  
{ @1MnJP  
oSavedFile = new RandomAccessFile(sName,"rw"); "9wD|wsz  
this.nPos = nPos; Dwp,d~z  
oSavedFile.seek(nPos); m
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} 0f^{Rp6  
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}!\O  
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public synchronized int write(byte[] b,int nStart,int nLen) i"WYcF|  
{ *'?7OL  
int n = -1; J
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try{ Z!)~?<gcq:  
oSavedFile.write(b,nStart,nLen); ilA45
@  
n = nLen; 0NXH449I=  
} mQj=-\p  
catch(IOException e) {KG6#/%;  
{ <kak9 6A  
e.printStackTrace (); FACw;/rW  
} Y@UkP+{f=  
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F$C6( C?  
return n; \D7bTn  
} CD$#}Id  
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} n
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hF%M!otcJ-  
/* qt@L&v}~j  
**SiteInfoBean.java JvpGxj  
*/ ]~({;;3o-  
package NetFox; m`/Nl<  
`(e:H  
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public class SiteInfoBean { /wV|;D^ )  
\N,ox(f?gW  
9)Fx;GxL  
private String sSiteURL; //Site's URL tt"<1 z@  
private String sFilePath; //Saved File's Path NRi5 Vp2=  
private String sFileName; //Saved File's Name [#PE'i4  
private int nSplitter; //Count of Splited Downloading File @ZjT_  
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public SiteInfoBean() Xz$4cI#n:  
{//nSplitter的缺省值为5 Yj%]|E-  
//default value of nSplitter is 5 a.Ho>(V/4  
this("","","",5); ^*K=wE}AG  
} r|Ui1f5  
(}: s[cs  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) UUah5$Iy  
{ BVQy@:K/  
sSiteURL= sURL; p/.8})c1r  
sFilePath = sPath; c{z$^)A/  
sFileName = sName; ;]{ee?Q^ld  
this.nSplitter = nSpiltter; B,%Vy!o  
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} @60D@Y  
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}E'0vf/  
public String getSSiteURL() 1F@k9[d~  
{ *FlPGBjJ  
return sSiteURL; iUx\3d,  
} )t6]F6!_  
,YYEn^:>  
XzUGlrp:Y#  
public void setSSiteURL(String value) z/@_?01T=  
{ }A#IBqf5  
sSiteURL = value; 2hh8G5IaQ  
} iOE. .xA:  
K7 e~%mY  
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public String getSFilePath() iI3:<j l  
{ J2UQq7-y  
return sFilePath; xoaO=7\io  
} +$2{u_m,  
S;|:ci<[=  
/jbAf]"F;  
public void setSFilePath(String value) \br!77  
{ Ey6R/M)?:y  
sFilePath = value; !l:GrT8J  
} ;nY#/%f  
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public String getSFileName() ><V*`{bD9)  
{ m,l/=M  
return sFileName; O%bbyR2  
} F3tps jQ  
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public void setSFileName(String value) Cux(v8=n  
{ H;H=8'  
sFileName = value; 7T~M`$h  
} [
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|3H+b,M5  
)2}R1K>  
public int getNSplitter() \2SbW7"/;P  
{
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return nSplitter; rzjVUPdnh  
} c_lHj#A(l  
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public void setNSplitter(int nCount) v4$/LUJZp  
{ 5
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nSplitter = nCount; )uPJ? 2S9  
} d,<ni"  
} NBikYxa  
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/* gI+8J.AG=  
**Utility.java FG?
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*/ la!]Y-s)'4  
package NetFox; 8@3K, [Mo  
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public class Utility { Jt~Ivn,  
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public Utility() .@1+}0  
{ -m@o\9Ic  
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,75)  
} L/3A g* ]  
.RD<]BxJ  
//线程睡眠 =c8}^3L~7  
public static void sleep(int nSecond) 7"(!]+BW!O  
{ TBlSZZ-55]  
try{ k,h602(  
Thread.sleep(nSecond); rb*|0ST  
} te_2"Z  
catch(Exception e) `lf_wB+I  
{ -,bFGTvYQ  
e.printStackTrace (); '&>"`q  
} , X5.|9  
} 1.hWgWDP  
aSR-.r  
//日志 `~1!nfFD  
public static void log(String sMsg) yR}.Xq/  
{ V<ESjK8  
System.err.println(sMsg); /dnwN7Gf  
} &kb`)F3nU  
FD=% 4#|  
c*USA eP  
public static void log(int sMsg) n<?U6~F&~  
{ qxL\G &~  
System.err.println(sMsg); 7qKz_O  
} rd <m:r  
} 2TK \pfD  
FO{=^I5YA  
1 ZdB6U0  
/* %6K7uvTq  
**TestMethod.java ;vx5 =^7P  
*/ 1gI7$y+?  
package NetFox; -I< >Ab  
Vk5Z[w a  
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public class TestMethod { X>(1fra4  
,67Q!/O  
A40DbD\^ad  
public TestMethod() >e]g T  
{ ///xx/weblogic60b2_win.exe /:|vJ|dJ  
try{ ,H7X_KbFD4  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Ee>VA_ss  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); WtSs:D  
SiteFileFetch fileFetch = new SiteFileFetch(bean); K#"=*p,  
fileFetch.start(); ,p2UshOmd
 
} Q*M#e  
catch(Exception e){e.printStackTrace ();} _3IT3mb2n  
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!-I,Dh-A  
} DE13x*2  
I8#2+$Be+@  
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public static void main(String[] args) t}t(fJHY`  
{ "2%z;!U1  
new TestMethod(); ?0qVyK_
1  
} s 6Wp"V(  
} BR|!ya+_2  
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