http断点续传简单实现（java)

/* I:bD~Fb3  
**SiteFileFetch.java S{4z?Ri, '  
*/ UJfT!==U  
package NetFox; >d"3<S ;b  
import java.io.*; Q|Y0,1eVp|  
import java.net.*; 7!,YNy%  
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public class SiteFileFetch extends Thread { p.}Ls)I  
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SiteInfoBean siteInfoBean = null; //文件信息Bean _lzyMEdr  
long[] nStartPos; //开始位置 LMi:%
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long[] nEndPos; //结束位置 >Rvx[`|O!m  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 JO=[YoTr  
long nFileLength; //文件长度 |(moWY=  
boolean bFirst = true; //是否第一次取文件 IK,|5]*Ar  
boolean bStop = false; //停止标志 :j|IP)-f  
File tmpFile; //文件下载的临时信息 gqXS~K9t  
DataOutputStream output; //输出到文件的输出流 6S6f\gAM  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ^-FX  
public SiteFileFetch(SiteInfoBean bean) throws IOException yR{x}Db
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{ 7n]65].t  
siteInfoBean = bean; Uv YF[@  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 7Dnp'*H  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); l`kWz5[~  
if(tmpFile.exists ()) 5aad$f  
{ >hBxY]< \  
bFirst = false; 1im^17X  
read_nPos(); +_XmlX A3Z  
} l4n)#?Q?  
else 8+]hpa,q  
{ y;mj^/SxK  
nStartPos = new long[bean.getNSplitter()]; #HS]NA|e@  
nEndPos = new long[bean.getNSplitter()]; y4h=Lki@
 
} iz
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[
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} M"%Q&o/I  
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public void run() KH\b_>wU2  
{ &//wSlL3  
//获得文件长度 E_KCNn-f  
//分割文件 UAR5^  
//实例FileSplitterFetch qE'9QQ>:b  
//启动FileSplitterFetch线程 e8YMX&0%  
//等待子线程返回 m<L;  
try{ 6wco&7   
if(bFirst) 988]}{w  
{ | mu+9  
nFileLength = getFileSize(); gP+fN$5'd  
if(nFileLength == -1) 1c JF/"v  
{ iU6Gp-<M,  
System.err.println("File Length is not known!"); rkiT1YTY  
} AiD[SR  
else if(nFileLength == -2) Fnk_\d6Ma  
{ -{^}"N  
System.err.println("File is not access!"); ?+T^O?r|O  
} >]o}}KF?  
else .0R v(Y  
{ \om%Q[F7a  
for(int i=0;i<nStartPos.length;i++) {3N'D2N  
{  L4uFNM]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); OL_{_K(w  
} Bgmn2-  
for(int i=0;i<nEndPos.length-1;i++) iC iZJ"  
{ RwS@I
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nEndPos = nStartPos[i+1]; T~h5B(J;  
} "c}@V*cO<d  
nEndPos[nEndPos.length-1] = nFileLength; <~ JO s2  
} 3\T2?w9u(  
} (KvROV);  
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//启动子线程 Ltjbxw"Qd  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; `jST  
for(int i=0;i<nStartPos.length;i++) bc , p}  
{ D&HV6#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), i#%aTRKHd6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), G,;,D9jO7  
nStartPos,nEndPos,i); EyY.KxCB  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~b{Gz6u>  
fileSplitterFetch.start(); ;[RZ0Uy=  
} nx0K$Ptq  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +cU>k}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); sB69R:U;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8w({\=
 
nEndPos = " + nFileLength); ;gC|  
// fileSplitterFetch[nPos.length-1].start(); |yo\R{&6  
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64:fs?H  
//等待子线程结束 mo~*C   
//int count = 0; p}[zt#v  
//是否结束while循环 Gycm,Cy  
boolean breakWhile = false; ktDC/8
  
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while(!bStop) Zw wqSyuGf  
{ ^&g=u5 d0  
write_nPos(); wcDRH)AW.  
Utility.sleep(500); VbBPB5 $q  
breakWhile = true; u{["50~  
] }f9JNf$  
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for(int i=0;i<nStartPos.length;i++) y\{%\$  
{ ax 41N25  
if(!fileSplitterFetch.bDownOver) DNP13wp@  
{ 
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breakWhile = false; }MUn/ [x  
break;  gk`zA  
} Z4IgBn(Z_}  
} '=P7""mN5  
if(breakWhile) %,ngRYxT#  
break; Le%ZV%,  
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//count++; q\H[am  
//if(count>4) ,]b~t0|B  
// siteStop(); k%^lF?_0I  
} tDAhyy73  
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F
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System.err.println("文件下载结束！"); r1fGJv1!o  
} B7]MGXC  
catch(Exception e){e.printStackTrace ();} ]vuwkn+)  
} _ 84ut  
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//获得文件长度 ,-z9 #t  
public long getFileSize() KF4PJi;*  
{ z5TuGYb<  
int nFileLength = -1; %6_AM  
try{ N!`e}Z6S  
URL url = new URL(siteInfoBean.getSSiteURL()); z3uW)GQ.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); yv)ux:P&+  
httpConnection.setRequestProperty("User-Agent","NetFox"); d:yqj:  
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int responseCode=httpConnection.getResponseCode(); aN(|'uO@  
if(responseCode>=400) qoAj] ")  
{ c_elShK8#  
processErrorCode(responseCode); \rPbK+G.  
return -2; //-2 represent access is error O(_[ayE  
} &5:tn=E  
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String sHeader; *YlV-C<}W"  
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for(int i=1;;i++) p0pWzwTG3  
{ @}kv-*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); VcoOeAKL  
//Utility.log(in.readLine()); *_?dVhxf  
sHeader=httpConnection.getHeaderFieldKey(i); dXnl'pFS  
if(sHeader!=null) Gm\/Y:U  
{ Gdg"gi!4  
if(sHeader.equals("Content-Length")) Ge<nxl<Bd  
{ 3N_"rNKD  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Bp@v,)8*  
break; a+Ac[>  
} w
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} 'R_g">B.  
else 4Fm90O  
break; rl0<Ls  
} 8.[SU  
} 'e6WDC1Am(  
catch(IOException e){e.printStackTrace ();} 7k8pZ  
catch(Exception e){e.printStackTrace ();} JY6 Qp  
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Utility.log(nFileLength); J(6oL   
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return nFileLength; DY^;EZ!hb  
} 0tU.(  
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` Jdb;  
//保存下载信息（文件指针位置） a1@Y3MQ;i  
private void write_nPos() %HJK;   
{ @!1x7%]G  
try{ J7g8D{4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); \QCJ4}\CS  
output.writeInt(nStartPos.length); Dbz3;t  
for(int i=0;i<nStartPos.length;i++) ^t#&@-'(d  
{ aSnFKB  
// output.writeLong(nPos); eYvWZJa4  
output.writeLong(fileSplitterFetch.nStartPos); 55fC~J<  
output.writeLong(fileSplitterFetch.nEndPos); ^=-y%kp"  
} Sb82}$sO  
output.close(); K9up:.{QQ  
} Qr{E[6  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} 5f 5f0|ok  
} :w^Ed%>y7  
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//读取保存的下载信息（文件指针位置） W}mn}gTQ  
private void read_nPos() >: g3k  
{ N <Xq]! K-  
try{ z.;ez}6%V  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 71t*%  
int nCount = input.readInt(); lp^<3o*1  
nStartPos = new long[nCount]; Ev}C<zk*  
nEndPos = new long[nCount]; #*UN
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for(int i=0;i<nStartPos.length;i++) $[a8$VY^Cm  
{ 0a XPPnuX  
nStartPos = input.readLong(); ]Yn_}Bq  
nEndPos = input.readLong(); Y<%@s}zc  
}  UWo]s.  
input.close(); pz.JWCU1  
} XLrwxj0  
catch(IOException e){e.printStackTrace ();} }*S `qW;B  
catch(Exception e){e.printStackTrace ();} yvO{:B8%  
} |M,iM]  
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private void processErrorCode(int nErrorCode) )u`[6,d  
{ 85Otss/mM  
System.err.println("Error Code : " + nErrorCode); y1+*
6|  
} z?*w8kU&>  
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//停止文件下载 IHv[v*4:  
public void siteStop() 9^#c|
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{ Evg_q>  
bStop = true; Eu@huN*/  
for(int i=0;i<nStartPos.length;i++) Oagsoik  
fileSplitterFetch.splitterStop(); c2'Lfgx4  
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} M:[ %[+6  
} \kMefU  
//负责部分文件的抓取 FE (ev 9@  
**FileSplitterFetch.java i/`m`qdg  
*/ #Oc] @  
package NetFox; j2StXq3  
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import java.io.*; OuID%p"O  
import java.net.*; (mTE;s(  
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public class FileSplitterFetch extends Thread { ( +Q&[E"87  
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String sURL; //File URL r")`Ph@yp  
long nStartPos; //File Snippet Start Position "!ug_'VW  
long nEndPos; //File Snippet End Position [6%VRqY  
int nThreadID; //Thread's ID %InA+5s`  
boolean bDownOver = false; //Downing is over c4^ks&)'  
boolean bStop = false; //Stop identical g"p%C:NN  
FileAccessI fileAccessI = null; //File Access interface C.Kh[V\Ut  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException -w}]fb2Q>  
{ C'.L20qW  
this.sURL = sURL; Bn#?zI  
this.nStartPos = nStart; j7$e28|_n  
this.nEndPos = nEnd; Oj3.q#)`Z  
nThreadID = id; {GK;63`1  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 j<VFn~*_  
} aW)-?(6>  
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public void run() -.u]Ge
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{ :t8b39
  
while(nStartPos < nEndPos && !bStop) @"Fme-~
 
{ s%nUaWp~  
%et }A93  
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try{ :8=ikwQ  
URL url = new URL(sURL); =jOv] /  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c[wla<dO*  
httpConnection.setRequestProperty("User-Agent","NetFox"); aeFe!`F  
String sProperty = "bytes="+nStartPos+"-"; 6}[I2F_^  
httpConnection.setRequestProperty("RANGE",sProperty); A+ZK4]xb  
Utility.log(sProperty); la0BiLzb]  
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InputStream input = httpConnection.getInputStream(); ;c-(ObSm  
//logResponseHead(httpConnection); 1 d}Z(My  
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byte[] b = new byte[1024]; C*)3e*T
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int nRead; GP!?^r:en  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^84G%)`&  
{ U@_dm/;0&  
nStartPos += fileAccessI.write(b,0,nRead); EUD~CZhS"k  
//if(nThreadID == 1) , pDnRRJ!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %p^wZtm  
} Xx."$l  
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Utility.log("Thread " + nThreadID + " is over!"); [R(`W#W  
bDownOver = true; Y!~49<;  
//nPos = fileAccessI.write (b,0,nRead); $+8cc\fq  
} Pk{_(ybaY  
catch(Exception e){e.printStackTrace ();} =9y[1t  
} LSa,1{  
} p4.wh|n  
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//打印回应的头信息 Cc+
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public void logResponseHead(HttpURLConnection con) l2zFKCGF(  
{ @Owb?(6?  
for(int i=1;;i++) we~[] \  
{ :q$.,EZ4#n  
String header=con.getHeaderFieldKey(i); V)Z}En["1  
if(header!=null) >Wm`v.-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); q8X feoUV  
Utility.log(header+" : "+con.getHeaderField(header)); m,*QP*  
else  $UMFNjL  
break; Ygm`ZA y  
} eJF5n#  
} 8p^bD}lN7  
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public void splitterStop() {@H6HqD  
{ yzbx .  
bStop = true; CJ/X}hi,  
} x5,++7Tz  
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} V]|^&A_c  
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/* ^W`<gR  
**FileAccess.java 5A)2} D]  
*//文件访问(定位，写) |4)>:d  
package NetFox; ;,C)
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import java.io.*; WZ-s--n#  
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public class FileAccessI implements Serializable{ *rM^;4Zt  
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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 G"-?&)M#a  
RandomAccessFile oSavedFile; (7mAt3n k  
long nPos; T%.8'9  
%824Cqdc  
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public FileAccessI() throws IOException B8nf,dj?X  
{ -E^vLB)O  
this("",0); bx#>BK!  
} iQ tNAj  
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public FileAccessI(String sName,long nPos) throws IOException AYt%`Y.!  
{ h%o%fH&F!  
oSavedFile = new RandomAccessFile(sName,"rw"); gy,ht3  
this.nPos = nPos; l Q'I  
oSavedFile.seek(nPos); )#BMTKA^  
} NTdixfR  
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public synchronized int write(byte[] b,int nStart,int nLen) ]9YJ,d@J  
{ $yn];0$J  
int n = -1; )<oJnxe]  
try{ 3)F|*F3R  
oSavedFile.write(b,nStart,nLen); =!kk|_0%E  
n = nLen; M`. tf_x  
} !S^AgZ~  
catch(IOException e) T m_bz&Q  
{ yWg@v+  
e.printStackTrace (); T_s_p  
} Y#!UPhg<  
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return n; !9u|fnC9  
} J4QXz[dG  
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} E[2m&3&  
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M}`B{]lLz  
/* bt"W(m&f  
**SiteInfoBean.java Ov};e  
*/ Z,RzN5eN  
package NetFox; aUzBV\Yd}  
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public class SiteInfoBean { gcE|#1>  
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)2pbpbWX>  
private String sSiteURL; //Site's URL {J{+FFsr(  
private String sFilePath; //Saved File's Path V[{6e  
private String sFileName; //Saved File's Name CpA|4'#  
private int nSplitter; //Count of Splited Downloading File qS403+Su1=  
dq7x3v^"ZG  
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public SiteInfoBean() y-T| #  
{//nSplitter的缺省值为5 ^M3~^lV  
//default value of nSplitter is 5 )`SES."  
this("","","",5); !Nu<xq@!  
} ?p9VO.^5  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) L; T8?+x  
{ :j5n7s?&=y  
sSiteURL= sURL; ST2.:v;lb  
sFilePath = sPath; @Py/K /  
sFileName = sName; 6FUw"|\u{  
this.nSplitter = nSpiltter; N96jJk  
~Fe${2
 
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} ~J5+i9T.)  
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public String getSSiteURL() pA`+hQNN  
{ nA?`BOe(  
return sSiteURL; hhSy0  
} X
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G %
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public void setSSiteURL(String value) stG~AC  
{ 8;z6=.4xtg  
sSiteURL = value; IYqBQnX}oM  
} @En^wN  
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public String getSFilePath() M^MdRu  
{ l*ayd>`~x  
return sFilePath; \qR7mI/*  
} `Y BC  


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tna .52*/  
public void setSFilePath(String value) @xQgY*f#  
{ *n;!G8\  
sFilePath = value; AcS|c:3MUy  
} O>qll6]{@  
`D>S;[~S7  
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public String getSFileName() #OBJzf*p  
{ 6S\C}U/  
return sFileName; >C7r:%  
} Cnnh7`  
^:6{22C{  
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public void setSFileName(String value) ~;Ov-^tp  
{ 3Th'paMG  
sFileName = value; 09dK0H3(  
} bQE};wM,  
k xP-,MD  
uJOJ-5}yt  
public int getNSplitter() (H)2s Y  
{ 4 d;|sI@  
return nSplitter; VK}fsOnj0  
} QN@CPuy  
0="%Y^N  
&?VQ,+[<
 
public void setNSplitter(int nCount) tDSJpW'd  
{ (]b!{kS  
nSplitter = nCount; =fu :@+  
} w<zIAQN  
} Ks=>K(V6  
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=NOH:#iQ  
/* [OHxonU  
**Utility.java |\QgX%  
*/ Rz(QC\(  
package NetFox; -9"['-WH,  
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public class Utility { 9dFy"y
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+cIUGFp}  
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public Utility() PH`9MXh
 
{ @[5xq  
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} =jlt5 z  
VGtC)mG8)  
//线程睡眠 &Ts-a$Z7?S  
public static void sleep(int nSecond) O_$m!5ug  
{ j2Tr$gx<  
try{ >"gf3rioW  
Thread.sleep(nSecond); W4[V}s5u  
} -cZDGt  
catch(Exception e) :80Z6F.k`  
{ ZaeqOVp/j  
e.printStackTrace (); *_R]*o!W'  
} [E+$?a=  
} HH
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W- i&sUgy  
//日志 Z^V6K3GSz-  
public static void log(String sMsg) N5*u]j  
{ +u!0rLb  
System.err.println(sMsg); #Xhdn\7  
} P/xKnm~  
K#*reJ}K  
!lEY=1nHOJ  
public static void log(int sMsg) SxdE?uCUS  
{ (ohq0Y  
System.err.println(sMsg); lrnyk(M}Q.  
} *F ?8c  
} U"q/rcA  
)E6;-rD0^+  
b`)){LR  
/* m_=$0m J$  
**TestMethod.java ^dP KDrKxh  
*/ *:>"q ej  
package NetFox; mocI&=EF2X  
D@.tkzU@E  
7h6,c/<  
public class TestMethod { VUVaaOm
O  
P8^hBv*  
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public TestMethod() `VKf3&|<A  
{ ///xx/weblogic60b2_win.exe {z(xFrY  
try{ .uyGYj-C  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =Vy`J)z9  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); &8%e\W\K:/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Y]{ >^`G  
fileFetch.start(); Swp;HW7x  
} |AcRIq  
catch(Exception e){e.printStackTrace ();} fRy^Q_~,  
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} ox:[f9.5  
+x_Rfk$fb  
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public static void main(String[] args) T%6&PrQ7  
{ rFaF Bd  
new TestMethod(); 9so6WIWc  
} p!sWYui  
} B*4}GPQ  
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