http断点续传简单实现（java)

/* IRQtA ZV$  
**SiteFileFetch.java ,<L4tp+y0  
*/ r[!~~yu/o  
package NetFox; )58O9b  
import java.io.*; \
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import java.net.*; h&j2mv(  
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public class SiteFileFetch extends Thread { o)5zvnu7  
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SiteInfoBean siteInfoBean = null; //文件信息Bean n0l|7:Mk  
long[] nStartPos; //开始位置 +zMhA p  
long[] nEndPos; //结束位置 )r46I$]>  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 GPHb-  
long nFileLength; //文件长度 + -Rf@  
boolean bFirst = true; //是否第一次取文件 i[KXkjr  
boolean bStop = false; //停止标志 Fl.?*KBz  
File tmpFile; //文件下载的临时信息 z|3v~,  
DataOutputStream output; //输出到文件的输出流 @]n8*n  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 1!^BcrG.  
public SiteFileFetch(SiteInfoBean bean) throws IOException #tKks:eL  
{ n3$=&  
siteInfoBean = bean; Q$U.vF7BnP  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); &$|~",  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >;Hx<FKxP  
if(tmpFile.exists ()) (X@\2M4@T#  
{ legWY)4D;  
bFirst = false; b~&cYk'  
read_nPos(); 5Yv*f:  
} D 1.59mHsD  
else 68?&`/t  
{ R_G2C@y*  
nStartPos = new long[bean.getNSplitter()]; AHs%?5YTY;  
nEndPos = new long[bean.getNSplitter()]; ,mm97I  
} !LH;K  
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} 9mHCms  
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public void run() E?+~S M1~  
{ a&G{3#l  
//获得文件长度 Kc[^Pu  
//分割文件 OF<:BaRs/  
//实例FileSplitterFetch GImPPF  
//启动FileSplitterFetch线程 ^*l dsc  
//等待子线程返回 C2R"96M7
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try{ >
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if(bFirst) KOe]JDU  
{ Kv* 1=HES  
nFileLength = getFileSize(); ;cf$u}+  
if(nFileLength == -1) (KC08  
{ )>h3IR  
System.err.println("File Length is not known!"); &5K3AL  
} uH$hMg  
else if(nFileLength == -2) ?x",VA  
{ e-`9-U%6  
System.err.println("File is not access!"); /{buFX2"}  
} yI8O#  
else @XG1d)sE  
{ eHUyV@  
for(int i=0;i<nStartPos.length;i++) x=rMjz-`_  
{ EB&hgz&_  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); MX~h>v3_R4  
} \ &|xMw[  
for(int i=0;i<nEndPos.length-1;i++) 'KmM%tN  
{ 7|=SZ+g  
nEndPos = nStartPos[i+1]; ]uhG&: }  
} Fb<'L5
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nEndPos[nEndPos.length-1] = nFileLength; 0(c,J$I]Z!  
} &kdW(;`  
} G$YF0Nc  
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//启动子线程 _lI(!tj(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8Q/cJ+&  
for(int i=0;i<nStartPos.length;i++) Tg O]q4  
{ H8"RdKwg?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,+BFpN'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), *8qRdI9  
nStartPos,nEndPos,i); RQ|K?^k v  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Vfd_nD^8oZ  
fileSplitterFetch.start(); 1y[~xxgE  
} R|Bi%q|4P  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N@0/
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); c%G~HOE=B  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", uq6>K/~D  
nEndPos = " + nFileLength); '`}D+IQ(j  
// fileSplitterFetch[nPos.length-1].start(); w\ '5lk,"  
M GC=L .  
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//等待子线程结束 %
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//int count = 0; vB7]L9=@"  
//是否结束while循环 w`boQ_Ir  
boolean breakWhile = false; Y_$!XIJ4  
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while(!bStop) zLr:zfl  
{ -GL.8"c[  
write_nPos(); b6e2a/x  
Utility.sleep(500); ^&F.T-(A  
breakWhile = true; g[b;1$  
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for(int i=0;i<nStartPos.length;i++) 0p3) t  
{ X..M!3
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if(!fileSplitterFetch.bDownOver) hT=E~|O  
{ O:V.;q2]U  
breakWhile = false; *W |  
break; Q.4+"JoG  
} 7zQGuGo(  
} D@w&[IF  
if(breakWhile) /FTP8XHwL)  
break; 
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#?M[
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//count++; I7XM2xM  
//if(count>4) toG- Dz&  
// siteStop(); j5hQ;~Fa|  
} p&XuNk  
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System.err.println("文件下载结束！"); ]$)};8;7W  
} T;k
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catch(Exception e){e.printStackTrace ();} Ktuv a3=>N  
} +;@R&Y  
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//获得文件长度 j*VYUM@y1\  
public long getFileSize() 29@m:=-}7  
{ s*CBYzOm  
int nFileLength = -1; $\oe}`#o  
try{ &xj,.;
  
URL url = new URL(siteInfoBean.getSSiteURL()); AA|G&&1y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9Z2aFW9  
httpConnection.setRequestProperty("User-Agent","NetFox"); ODCN~7-@  
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int responseCode=httpConnection.getResponseCode(); vKbGG  
if(responseCode>=400) +^,&z}( Ak  
{ }i;!p Ue$  
processErrorCode(responseCode); !9zs>T&9a\  
return -2; //-2 represent access is error 0
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} eZpi+BRS6  
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String sHeader; tpV61L   
@!\l
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for(int i=1;;i++) n?^X/R.22  
{ >Co@K^'  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); rt! lc-g%/  
//Utility.log(in.readLine()); zW95qxXg  
sHeader=httpConnection.getHeaderFieldKey(i); QUdF`_U7  
if(sHeader!=null) u"q!p5P%q  
{ UD'e%IVw  
if(sHeader.equals("Content-Length")) f,+ONV]5Tt  
{ +P*,i$MV  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); y9GaxW*&  
break; "Bn]-o|r  
} vdulrnGqL  
} `Z#]lS?  
else pKL^<'w0  
break; iaaD1<m  
} b\"2O4K,)  
} F>q%~  
catch(IOException e){e.printStackTrace ();} rYA4(rYq  
catch(Exception e){e.printStackTrace ();} xe1xP@e?  
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Utility.log(nFileLength); nR?m,J  
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return nFileLength; u $T'#p1  
} /#4BUfY f  
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//保存下载信息（文件指针位置） }15ooe%  
private void write_nPos() 0'y3iar  
{ gl6*bB=  
try{ Y4/ !b  
output = new DataOutputStream(new FileOutputStream(tmpFile)); jDM^e4U.l  
output.writeInt(nStartPos.length); <+7-^o_  
for(int i=0;i<nStartPos.length;i++) !7kca#,X  
{ DO=zxdTI!  
// output.writeLong(nPos); qg-?Z,EB  
output.writeLong(fileSplitterFetch.nStartPos); WXE{uGc  
output.writeLong(fileSplitterFetch.nEndPos); DvXbbhp  
} (AgM7H0  
output.close(); x42m+5/  
} DU[vLe|Z  
catch(IOException e){e.printStackTrace ();} @y\M8C8  
catch(Exception e){e.printStackTrace ();} J3=^+/g  
} .zyi'Kj  
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8:0.Pi(ln@  
//读取保存的下载信息（文件指针位置） 9Lxa?Y1  
private void read_nPos() ,ffH:3F  
{ KbF,jm5  
try{ 9/S-=VOe.t  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); U_c9T>=  
int nCount = input.readInt(); s@bo df&  
nStartPos = new long[nCount]; X5D}<J2"  
nEndPos = new long[nCount]; H`ZUI8-  
for(int i=0;i<nStartPos.length;i++) jJCd2O]  
{ Q2/ZO2  
nStartPos = input.readLong(); e?~6HP^%.  
nEndPos = input.readLong(); T#sKld  
} I_@XHhyVZ  
input.close(); i;B)@op.#  
} s5ddGiZnBT  
catch(IOException e){e.printStackTrace ();} .B9rG~  
catch(Exception e){e.printStackTrace ();} wrW768WR  
} b]U%|bp  
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private void processErrorCode(int nErrorCode) "#mr?h_  
{ j_*#"}Lcp  
System.err.println("Error Code : " + nErrorCode); e|ngnkf(G  
} x5}Ru0Z  
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//停止文件下载 ,.<l^sj5  
public void siteStop() <}$o=>'  
{ 8wqHr@}p  
bStop = true;
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for(int i=0;i<nStartPos.length;i++) M7;P)da  
fileSplitterFetch.splitterStop(); ajz%3/R  
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} J0M7f]  
} *:3`$`\54  
//负责部分文件的抓取 bO%bMZWB!y  
**FileSplitterFetch.java RcH",*U  
*/ f?1?$Sp/W  
package NetFox; O=PyXOf  
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import java.io.*; ^H1B62_  
import java.net.*; 8D U|j-I8  
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public class FileSplitterFetch extends Thread { g2v0!  
?_9A`LC*  
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String sURL; //File URL 4c*?9r@  
long nStartPos; //File Snippet Start Position EI*B(  
long nEndPos; //File Snippet End Position -*u7MFq_  
int nThreadID; //Thread's ID /=}w%-;/;  
boolean bDownOver = false; //Downing is over L}1|R*b  
boolean bStop = false; //Stop identical >>voLDDd  
FileAccessI fileAccessI = null; //File Access interface @exeHcW61  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #B3P3\  
{ x_vaYUl)  
this.sURL = sURL; 4jlUyAD  
this.nStartPos = nStart; ljTnxg/? W  
this.nEndPos = nEnd; _Jc[`2Uv_c  
nThreadID = id; rn7eY  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {]/}3t  
} R(sPU>`MX  
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public void run() ew#t4~hh  
{ B6&;nU>;  
while(nStartPos < nEndPos && !bStop) %EuJ~;x(Mg  
{ 5 #)5Z8`X  
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try{ 90oG+T4  
URL url = new URL(sURL); Ccld;c&+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ndn)}Z!0h  
httpConnection.setRequestProperty("User-Agent","NetFox"); _h2axXFhT  
String sProperty = "bytes="+nStartPos+"-"; 8[S
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httpConnection.setRequestProperty("RANGE",sProperty); B\,pbOE?#  
Utility.log(sProperty); 9@LL_r`?<  
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InputStream input = httpConnection.getInputStream(); >TT4;ph  
//logResponseHead(httpConnection); P".CZyI-i  
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byte[] b = new byte[1024]; }j^asuf~c  
int nRead; ?CgqHmf\\(  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) J|-X?V;ZW  
{ x78`dX  
nStartPos += fileAccessI.write(b,0,nRead); N,
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//if(nThreadID == 1) "NY[&S  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5G"DgG*<  
} u:Fa1 !4JR  
2 5DXJb^:  
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Utility.log("Thread " + nThreadID + " is over!"); 88]V6Rm9[*  
bDownOver = true; nm)H\i  
//nPos = fileAccessI.write (b,0,nRead); J3OxM--8"  
} 1&JPyW  
catch(Exception e){e.printStackTrace ();} SW!lSIk  
} ToWiXH)4
 
} @kCFc
}  
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//打印回应的头信息 b*w@kLLN  
public void logResponseHead(HttpURLConnection con) ?6;9r[ p  
{ W_:3Sj l'  
for(int i=1;;i++) i^9,.$<1  
{ =]k0*\PS  
String header=con.getHeaderFieldKey(i); ),ur!v  
if(header!=null) cn62:p]5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); m5c?A+@fZ  
Utility.log(header+" : "+con.getHeaderField(header)); %~eIx=s  
else TUw+A6u:p  
break; {O ]^8#v^  
} AI{Tw>hZ  
} ;m<22@,E&  
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public void splitterStop() M3m!u[6|  
{ N~rA/B]T  
bStop = true; @ev"{dY  
} I$.HG]  
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v
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} wKxw|Fpn  
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/* [D
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**FileAccess.java V iY-&q'  
*//文件访问(定位，写) `1}WQS  
package NetFox; aQjs5RbP~  
import java.io.*; 05o)Q &`  
:G3PdQb^  
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public class FileAccessI implements Serializable{ ENZjRf4  
-|K^!G  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Iw)}YZmn  
RandomAccessFile oSavedFile; =geopktpf  
long nPos; H(L.k;B  
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.|\}]
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public FileAccessI() throws IOException cQg:
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{ 4= 7#=F1  
this("",0); \9 ,a"g  
} !3O8B0K)v  
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73Zx`00  
public FileAccessI(String sName,long nPos) throws IOException S2y_5XJ<D  
{ tx` Z?K[  
oSavedFile = new RandomAccessFile(sName,"rw"); w)C/EHF  
this.nPos = nPos; @c;XwU]2t  
oSavedFile.seek(nPos); z):LF<  
} b/[$bZD5o  
v2w|?26Lf  
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public synchronized int write(byte[] b,int nStart,int nLen) ^/6LVB*  
{ 1zNh& "  
int n = -1; vIq>QXb;d  
try{ <M)
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oSavedFile.write(b,nStart,nLen); VQ}N&H)
`  
n = nLen;  }?eO.l{  
} xUW\P$  
catch(IOException e) |Y-{)5/5}  
{ $6[%NQp  
e.printStackTrace (); g=#Cc( q  
} 4{PN9i E  
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return n; e1<9:h+  
} PiwMl)E|!  
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} 1tZ7%0R\g]  
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/* B4 k5IS  
**SiteInfoBean.java *A&A V||q  
*/ Z=+Tw!wR>  
package NetFox; @23?II$=@  
I K9plsd*  
,=a+;D]'  
public class SiteInfoBean { ]F{F+r  
#]rfKHW9  
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private String sSiteURL; //Site's URL $~3?n
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private String sFilePath; //Saved File's Path O*SJx
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private String sFileName; //Saved File's Name FOyANN'  
private int nSplitter; //Count of Splited Downloading File wC>}9
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7|@FN7]5NF  
public SiteInfoBean()
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{//nSplitter的缺省值为5 _^Z v[P  
//default value of nSplitter is 5 W{$J)iQ  
this("","","",5); iFOa9!_0n  
} awU!3)B  
(^
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <)$e*HrI  
{ XQ'$J_hC  
sSiteURL= sURL; ,Gi%D3lA  
sFilePath = sPath; \? n<UsI  
sFileName = sName; u5.zckV  
this.nSplitter = nSpiltter; )H1\4LeP  
:Z[|B(U  
h wi!C}  
} ~hxW3e  
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public String getSSiteURL() g#iRkz%l)&  
{ Vl^p3f[  
return sSiteURL; 3^Q;On|  
} {_G_YL[  
)%JjV(:  
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public void setSSiteURL(String value) 
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{ &c^tJ-s  
sSiteURL = value; *snY|hF  
} %$<v:eMAs  
*DgRF/S  
%oOSmt  
public String getSFilePath() 8 \"A-+_Q  
{ I]z4}#+cX  
return sFilePath; hg7_ZjO  
} B)x^S >  
3:aj8F2
 
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public void setSFilePath(String value) "sSY[6Kp!  
{ .wO-2h{Q  
sFilePath = value; !GJT-[  
} Q5&|1m Pb  
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public String getSFileName() k?}y@$[)  
{ l(pP*2  
return sFileName; 6`@6k2]  
} @rv)J[7Y&  
q%/\  
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public void setSFileName(String value) k5|GN Y6a  
{ *EPJeblAV  
sFileName = value;  6o1[fr  
} Y%!k'\n[2  
{
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public int getNSplitter() G '%ZPh89  
{ uf1s}/M  
return nSplitter; x9o(q`N  
} *^iSP(dg
 
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public void setNSplitter(int nCount) 9+b){W  
{ j|>^wB  
nSplitter = nCount; #bS}?fj  
} Us\Nmso z  
} N[I ?x5:u  
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/* kZ0z]Y  
**Utility.java $T_>WUiK  
*/ +Mb}70^  
package NetFox; jItVAmC=i  
;D<
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public class Utility { Q yhu=_&  
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d/b\:[B@  
public Utility() `NQ;|!  
{ ,E8g~ZUY9  
ey$H2zmo  
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} DB0?H+8t  
gX`C76P!  
//线程睡眠 {*"\68e  
public static void sleep(int nSecond) N"7BV  
{ (_Th4'(@Y  
try{ M}`T-"
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Thread.sleep(nSecond); I0N~>SpZ5  
} iGBHlw;A  
catch(Exception e) CropHB/t  
{ ^[6#Kw&E  
e.printStackTrace (); (ylZ[M&B:  
} iM$iZ;Tp
 
} +fHqGZ]  
4YXp,U  
//日志 mln%Rd6u/  
public static void log(String sMsg) S3Fj /2Q8  
{ s~A:*2\  
System.err.println(sMsg); F5+!Gb En  
} a :CeI  
OX}ZdM!&f  
V"T5<HA9  
public static void log(int sMsg) w6ck wn,  
{ 4 g8t  
System.err.println(sMsg);
8
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} <.ZD.u  
} Z^.qX\<M  
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{>3w"(f7o  
/* Bw.?Me)mf|  
**TestMethod.java [7l5p(=  
*/ !,~C  
package NetFox; Gw#z:gX2  
{5SJ0'.B2g  
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public class TestMethod { Yez  
aW#^@||B  
]sqp^tQ`e  
public TestMethod() qxHsmGV  
{ ///xx/weblogic60b2_win.exe -3SRGr  
try{ C9j5Pd5q1L  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); "uBr]N:  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6Z-[-0o+g  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ~2UmX'  
fileFetch.start(); UdFYG^i  
} p]6/1&t="  
catch(Exception e){e.printStackTrace ();} w!RJ8  
,UfB{BW  
"R[6Q ^vw  
} -];Hb'M.!e  
h: zi
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public static void main(String[] args) scZ'/(b-E  
{ $oIGlKc:L  
new TestMethod(); iJk/fvi  
} !6_tdZ  
} zTze
%  
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