http断点续传简单实现（java)

/* l +RT>jAmK  
**SiteFileFetch.java ~6!{\un   
*/ $7~k#_#PC  
package NetFox; :NJb<%$  
import java.io.*; zR:Mg\  
import java.net.*; lC&U9=
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public class SiteFileFetch extends Thread { "e62g  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ?2hoY  
long[] nStartPos; //开始位置 [/uqH  
long[] nEndPos; //结束位置 I$sJ8\|gw'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 F VW&&ft  
long nFileLength; //文件长度 QXx<Hi^ /  
boolean bFirst = true; //是否第一次取文件 3~H_UGw  
boolean bStop = false; //停止标志 oLVy?M%{P  
File tmpFile; //文件下载的临时信息 fk-zT
 
DataOutputStream output; //输出到文件的输出流 *FyBkG
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） TR3_!0  
public SiteFileFetch(SiteInfoBean bean) throws IOException @!/
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{ cn (-{dCXM  
siteInfoBean = bean; P!yE{_%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); N{v <z 6  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Zh.5\&bm  
if(tmpFile.exists ()) (Qmpz  
{ `hYj0:*)S$  
bFirst = false; )s^D}I(  
read_nPos(); b%<-(o/  
} 9%aBW7@SK  
else ''P.~~ezr5  
{ In)8AK(Hw  
nStartPos = new long[bean.getNSplitter()]; F?Cx"JYix  
nEndPos = new long[bean.getNSplitter()]; [#$:X+lw  
} *gMo(-tN  
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} >Qg`Us
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public void run() e]-bB#-A  
{ Z{"/Ae5]  
//获得文件长度 xu9K\/{7  
//分割文件 %9ef[,WT  
//实例FileSplitterFetch guJS;VC6U  
//启动FileSplitterFetch线程 jA@jsv  
//等待子线程返回 ^PDz"L<*  
try{ `j+aAxJ=\  
if(bFirst) {RFpTh7f:  
{ tow0/Jt  
nFileLength = getFileSize(); 9m^"ca  
if(nFileLength == -1) !p$z8~  
{ LbX>@2(&  
System.err.println("File Length is not known!"); {&Kck>C'  
} Cx(|ZD^  
else if(nFileLength == -2) .$nQD.X  
{ !DgN@P.o  
System.err.println("File is not access!"); :^~I@)"ov  
} v eP)ElX  
else ia#
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{ KLVkPix;$  
for(int i=0;i<nStartPos.length;i++) 1b*
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{ $80TRB#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ^
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} i*-[-hn-V  
for(int i=0;i<nEndPos.length-1;i++) <Uj~S  
{ /SDN7M]m!  
nEndPos = nStartPos[i+1]; :iW+CD)j  
} g}(yq:D  
nEndPos[nEndPos.length-1] = nFileLength; f|U;4{k  
} (`C#Tq  
} &/XRiK1"0  
|C;8GSw>|F  
.!#0eAT  
//启动子线程 kg0X2^#b  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8%C7!l q  
for(int i=0;i<nStartPos.length;i++) bs_>!H1  
{ 7 YS'Tf  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fC6zDTis8A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4yOYw*X  
nStartPos,nEndPos,i); ^y" #2Ov  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m/ D~D~  
fileSplitterFetch.start(); [4p~iGC  
} T!![7Rs  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1Q[I$=-F  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); B49: R>  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 9]u=b\fzZ  
nEndPos = " + nFileLength); &6ymGo  
// fileSplitterFetch[nPos.length-1].start(); G;RFY!o  
?w^MnK0U)  
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//等待子线程结束 6}z-X*  
//int count = 0; [)efh9P*  
//是否结束while循环 & OO0v*@{  
boolean breakWhile = false; Jd]
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l\f /(&,  
while(!bStop) nZtMF%j'  
{ AW{"9f4  
write_nPos(); \zCw&#D0Z  
Utility.sleep(500); rdQKzJiX=U  
breakWhile = true; E`0mn7.t  
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for(int i=0;i<nStartPos.length;i++) 1>~bzXY#  
{ +8xC%eE  
if(!fileSplitterFetch.bDownOver) e\8|6<o[  
{ {[I]pm~n  
breakWhile = false; &\Ze<u  
break; {l0[`"EF  
} qV$\E=%fhM  
} 1]&FB{l  
if(breakWhile) QsemN7B"<  
break; &':Ecmo~`  
MpNgp)%>  
]z77hcjB1  
//count++; 0jJ:WPR  
//if(count>4) " ""k}M2A  
// siteStop(); Y5fz_ [("  
} EvP\;7B  
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;_~9".'<d  
System.err.println("文件下载结束！"); ,K WIuCU;  
} f>CJ1;][{  
catch(Exception e){e.printStackTrace ();} wU}%]FqtZ=  
} oKMr Pr[`  
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 =w5]o@  
//获得文件长度 WGwIc7  
public long getFileSize() (=-6'23q)  
{ {j8M78}3  
int nFileLength = -1; GBY-WN4sc[  
try{ w}qLI4  
URL url = new URL(siteInfoBean.getSSiteURL()); C0gY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I7 = 4%)A  
httpConnection.setRequestProperty("User-Agent","NetFox"); VPr`[XPXb  
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int responseCode=httpConnection.getResponseCode(); 0FcG;i+  
if(responseCode>=400) i5 0c N<o  
{
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processErrorCode(responseCode); LgxsO:mi  
return -2; //-2 represent access is error q o6~)Aws  
} fZiwuq!_  
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String sHeader; `iNH`:[w  
nv<t$r  
2!_DkE  
for(int i=1;;i++) {)n@Rq\=v  
{ 6z5wFzJv?q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());  X`20=x  
//Utility.log(in.readLine()); K(,MtY*  
sHeader=httpConnection.getHeaderFieldKey(i); ~l8w]R3A  
if(sHeader!=null) TD sjNFe3  
{ |ju+{+  
if(sHeader.equals("Content-Length")) Alk+MwjR  
{ vW-o%u*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); cE^Ljk  
break; '2Lx>nByk  
} fuU 3?SG  
} 0|DyYu  
else \1O wZ@  
break; -asjBSo*D  
} SyI\ulmL  
} t)5.m}  
catch(IOException e){e.printStackTrace ();} 5\Rg%Ezl  
catch(Exception e){e.printStackTrace ();} TQtH
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Utility.log(nFileLength); 2fgYcQ8`  
? q_%  
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return nFileLength; ?_B'#,tI  
} Q@uWh:  
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=M6{{lI/  
//保存下载信息（文件指针位置） vq+4so )/S  
private void write_nPos() HB,?}S#TP  
{ r>}z|I'  
try{ "g*`G<W_s  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Z*b$&nM  
output.writeInt(nStartPos.length); I Z|EPzS  
for(int i=0;i<nStartPos.length;i++) `An p;el  
{ au]W*;x  
// output.writeLong(nPos); g~2=he\C  
output.writeLong(fileSplitterFetch.nStartPos); F1S0C>N?5  
output.writeLong(fileSplitterFetch.nEndPos); E[i#8_  
} B@@tKn_CQ  
output.close(); C[';B)a  
} T[I7.8g  
catch(IOException e){e.printStackTrace ();} [Op^l%BC  
catch(Exception e){e.printStackTrace ();} }lXor~_i  
} \<hHZS  
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//读取保存的下载信息（文件指针位置） jrxq558  
private void read_nPos() "sIww  
{ =4sx(<  
try{ 0e07pF/!  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); l$kO%E'  
int nCount = input.readInt(); 
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nStartPos = new long[nCount]; dq
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nEndPos = new long[nCount]; a*t @k*d_  
for(int i=0;i<nStartPos.length;i++) &'`ki0Xh;  
{ ]0O3kiVQ  
nStartPos = input.readLong(); q{%~(A5*H  
nEndPos = input.readLong(); K%_UNivN  
} ;<GK{8  
input.close(); '(SivD  
} ~N/a\%`  
catch(IOException e){e.printStackTrace ();} bPif"dhHe  
catch(Exception e){e.printStackTrace ();} .'.bokl/  
} ]rSg,Q>E  
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0  
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private void processErrorCode(int nErrorCode) yJ`{\7Uqg  
{ ;" D~F  
System.err.println("Error Code : " + nErrorCode); w ~"%&SNN  
} :P ]D`b6p  
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1M6^Brx  
//停止文件下载 ,
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public void siteStop() o~W,VhCP
 
{ 'r(g5H1}gi  
bStop = true; H|7XfM  
for(int i=0;i<nStartPos.length;i++) +sTPTCLE  
fileSplitterFetch.splitterStop(); W8Wjq DQ  
p] N/]2rR  
=}@1Z~  
} KX3A|
  
} sP}u zS  
//负责部分文件的抓取 +Wgfxk'{  
**FileSplitterFetch.java 19-V;F@;  
*/ m`n~-_  
package NetFox; SjY|aW+wAL  
|H]0pbC)w  
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import java.io.*; FA;-D5=
 
import java.net.*; ?Z4%u8Krvz  
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public class FileSplitterFetch extends Thread { 4*9t:D|}  
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String sURL; //File URL #D%6b  
long nStartPos; //File Snippet Start Position Vp0_R9oQ  
long nEndPos; //File Snippet End Position ~R~.D  
int nThreadID; //Thread's ID +A^|aQ  
boolean bDownOver = false; //Downing is over )n1[#x^I  
boolean bStop = false; //Stop identical `u7^r^>A  
FileAccessI fileAccessI = null; //File Access interface uFb 9Ic]`  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >dJ~  
{ <%`Rku  
this.sURL = sURL; ;"ESN)*|i  
this.nStartPos = nStart; +Mhk<A[s  
this.nEndPos = nEnd; L|:C
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nThreadID = id; Ctn?O~u  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 FC6~V6R  
} C^;8M
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public void run() {&^PDa|nD  
{ ZZHzC+O#^  
while(nStartPos < nEndPos && !bStop) A>e-eD xi  
{ @iXBy:@  
}p)Hw2  
*h=>*t?I2  
try{ -*~ @?  
URL url = new URL(sURL); wfEL .h  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %.]#3tW  
httpConnection.setRequestProperty("User-Agent","NetFox"); HwZl"!;Mry  
String sProperty = "bytes="+nStartPos+"-"; ]4V1]  
httpConnection.setRequestProperty("RANGE",sProperty); *]h"J]  
Utility.log(sProperty); 5 r_Z3/%  
`Mbs6AJ  
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InputStream input = httpConnection.getInputStream(); %6rSLBw3  
//logResponseHead(httpConnection); n-],!pL^  
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byte[] b = new byte[1024];
+:=FcsY  
int nRead; ceD6q~)  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 'UxI-Lt  
{ 44B D2`nF  
nStartPos += fileAccessI.write(b,0,nRead); 0bc>yZ\R  
//if(nThreadID == 1) v_pe=LC{-e  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); DO~[VK%|  
} |e+3d3T35  
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}!>\Ja<\  
Utility.log("Thread " + nThreadID + " is over!"); &z5?]`ALu  
bDownOver = true; :t9![y[=
|  
//nPos = fileAccessI.write (b,0,nRead); 83 R_8  
} im9EV|;  
catch(Exception e){e.printStackTrace ();} rl~Rb
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} w+)wrJTtm  
} DNqV]N_W  
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+HRtuRv0T  
//打印回应的头信息 &a e!lB  
public void logResponseHead(HttpURLConnection con) +/eJ#Xw3u8  
{ kONn7Itbu  
for(int i=1;;i++) V9}\0joM  
{ =uNc\a
(  
String header=con.getHeaderFieldKey(i); <t
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if(header!=null) LVm']_
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); @lWNSf  
Utility.log(header+" : "+con.getHeaderField(header)); ":qHDL3  
else B[EOz\?
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break; D_$N2>I-  
} ~"vS$>+  
} d}Guj/cx,  
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public void splitterStop() KWD{_h{R  
{ ar,v/l>d4N  
bStop = true; x7^VU5w#  
} O;V^Fk(  
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} cC/32SmY4  
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/* bx{njo1Mr  
**FileAccess.java x0{B7/FN  
*//文件访问(定位，写) e1JHN  
package NetFox; /U!B2%vq_  
import java.io.*; 8au Gz ,"  
a'Odw2Q_  
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public class FileAccessI implements Serializable{ m;rr7{7X  
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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 +HWFoK  
RandomAccessFile oSavedFile; [bX^_ Y  
long nPos; LH+Bu%s  
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public FileAccessI() throws IOException 09P2<oFLn  
{ 2_3os P\Z  
this("",0); s?S e]?i  
} F;_o`h  
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public FileAccessI(String sName,long nPos) throws IOException 3kUb cm  
{ SEg{Gso9b  
oSavedFile = new RandomAccessFile(sName,"rw"); lqh:c  
this.nPos = nPos; )=#Js<&3:  
oSavedFile.seek(nPos); .mqMz
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} R1Q,
m  
Eu
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public synchronized int write(byte[] b,int nStart,int nLen) 6(htpT%J  
{ FYE(lEjxi  
int n = -1; CH!\uK22  
try{ L>WxAeyu1K  
oSavedFile.write(b,nStart,nLen); 62.Cq!~  
n = nLen; *sB'D+-/  
} @gf <%>  
catch(IOException e) }2*qv4},!  
{ $RF.L
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e.printStackTrace (); 1|>vk+;1h  
} \Wppl,"6c  
|9$C%@8  
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return n; jpR]V86G  
} 'x?|tKzd  
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} [h' 22W  
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/* @V1FBw9S!@  
**SiteInfoBean.java ]{{%d4  
*/ A(BjU:D(Oj  
package NetFox; [9~EH
8  
#wvGS%
 
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public class SiteInfoBean { s-x1<+E(  

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4XJ']M(5;  
private String sSiteURL; //Site's URL u|"YS-dH  
private String sFilePath; //Saved File's Path A>S7Ap4z>  
private String sFileName; //Saved File's Name 'h~IbP  
private int nSplitter; //Count of Splited Downloading File C9k"QPE  
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public SiteInfoBean() l$l6,OzS@  
{//nSplitter的缺省值为5 /J!hKK^k  
//default value of nSplitter is 5 )G]J@36  
this("","","",5); }> C?Zx*  
} 6wq%4RI0  
|rhB@k  
~WV1t][  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #jj(S\WY  
{ w+!V,lU"^  
sSiteURL= sURL; Dq!YB[Z$:  
sFilePath = sPath; ]PL\;[b>  
sFileName = sName; l_+q a6C*  
this.nSplitter = nSpiltter; #zSNDv`  
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aGE} EK}  
} _XrlCLp: d  
XJS^{=/  
+Bt%W%_X  
public String getSSiteURL() [,~;n@jz  
{ ~e){2_J&n  
return sSiteURL; XC/M:2$  
} 56NDU>j$  
l}g_<  
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public void setSSiteURL(String value) B4m34)EOE  
{ %
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sSiteURL = value; 'q8:1i9\[  
} 7vGAuTfi/@  
yB;K|MXy?  
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public String getSFilePath() G(hn
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{ iZ ;562Mo  
return sFilePath; iy_3#x5>  
} jcxeXp|00  
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public void setSFilePath(String value) $V_w4!:Q  
{ _XI,z0(  
sFilePath = value; '0qKb*  
} 6gq`V,  
"#%9dWy  
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public String getSFileName() 2)q$HUIX  
{ 5* ~EdT  
return sFileName; W[73q>'  
} 7V~ gqum  
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public void setSFileName(String value) a)/ }T  
{ <Lq.J`|+  
sFileName = value; XJ7mvLM;  
} 0IbR>zFg.  
{r?Ly15  
emS7q|^  
public int getNSplitter() RUV:  
{ G\r>3Ys  
return nSplitter; z}P1+Pm  
} k3e?:t 9  
Z&J.8A]L  
M >s,I^  
public void setNSplitter(int nCount) jsw0"d(  
{ 0"c(n0L  
nSplitter = nCount; &[-b#&y  
} 'c/Z
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} gG,gL9o  
Q\Nz^~dQ:Y  
tWI4x3&2  
/* :k oXS  
**Utility.java X&|y|  
*/ OjY#xO+'  
package NetFox; !}&f2!?.W  
X>s'_F?  
inv 5
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public class Utility { zVtNT@1K>u  
,*{9g6  
?C|b>wM/  
public Utility() 4-\gha  
{ =:7OS>x  
/AUXO]  
9]*hP](  
} P}$DCD<$U  
#p|7\Y  
//线程睡眠 ch:0qgJ  
public static void sleep(int nSecond) `1U?^9Nf  
{ =%G<S'2'  
try{ 1 c4I`#_v  
Thread.sleep(nSecond); + |d[q?  
} 8>~\R=SC  
catch(Exception e) ugMfpT)  
{ a?X{k|;!7u  
e.printStackTrace (); b:>t1S Ul  
} @G>Q(a*,  
} KZt4 dr  
*
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//日志 58.b@@T  
public static void log(String sMsg) N\WEp?%~  
{ /?g:`NT  
System.err.println(sMsg); j692M.A  
} Z{J{6j  
S2EeC&-AR  
Wk&g!FR  
public static void log(int sMsg) I~P]_DmM  
{ &KZr`"cT#  
System.err.println(sMsg); *wVWyC  
} $bT<8:g  
} @{y[2M} %]  
{Kkut?5  
pSlosv(6  
/* d~-Cr-s4  
**TestMethod.java ,"Nfo`7  
*/ ('7qJkV  
package NetFox; 12MWO_'g8  
[N4#R  
3BWYSJ|  
public class TestMethod { LU7d\Ch  
h1`u-tc2x  
/kKF|Hg`c  
public TestMethod() 7`IoQvX  
{ ///xx/weblogic60b2_win.exe 1:r
8p6  
try{ 2En^su$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); C:WXI;*cr  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); |X$O'Gf#n  
SiteFileFetch fileFetch = new SiteFileFetch(bean); .Q^8_'ZG  
fileFetch.start(); bzt(;>_8  
} o> i`Jq&  
catch(Exception e){e.printStackTrace ();} *[^[!'kT&  
9e*v&A2Y'  
vUU)zZB~  
} =6N%;2`84  
2!+saf^-,  
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public static void main(String[] args) bdUe,2Yin  
{ ;m[-yqX  
new TestMethod(); 3RyB 0 n  
} '*6S0zt  
} @1UC9}>  
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