http断点续传简单实现（java)

/* GCP{Z]u  
**SiteFileFetch.java v9t47>V  
*/ DnG/ n  
package NetFox; &O+sK4P  
import java.io.*; }&Wp3EWw  
import java.net.*; |8DH4*y!  
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public class SiteFileFetch extends Thread { wVvqw/j*f  
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SiteInfoBean siteInfoBean = null; //文件信息Bean W9&0k+#^  
long[] nStartPos; //开始位置 93E,  
long[] nEndPos; //结束位置 7d|*postv  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 x9x#'H3  
long nFileLength; //文件长度 .])>A')r  
boolean bFirst = true; //是否第一次取文件 SE,o7_k'S  
boolean bStop = false; //停止标志 .0n
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File tmpFile; //文件下载的临时信息 ),nCq^Bp  
DataOutputStream output; //输出到文件的输出流 iA55yT
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} * ?
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） h*;g0QBkl  
public SiteFileFetch(SiteInfoBean bean) throws IOException b(PHZCy#  
{ Sk6b`W7$  
siteInfoBean = bean; ;mf4U85  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); %XEKhy  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0On?{Bw  
if(tmpFile.exists ()) !G)mjvEe  
{ Kcs
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bFirst = false; 8iMF8\  
read_nPos(); E;6Y? vJ  
} Fb<n0[m  
else u @{E{  
{ Zdv.PGn  
nStartPos = new long[bean.getNSplitter()]; 9">zdFC'  
nEndPos = new long[bean.getNSplitter()]; ,N;))3  
} w)45SZ.  
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} ksB  
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public void run() u] F70C^~  
{ Ni+3b  
//获得文件长度 Jt##rVN  
//分割文件
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//实例FileSplitterFetch ayV6m  
//启动FileSplitterFetch线程 >;&Gz-lm  
//等待子线程返回 "KMLk  
try{ jrIA]K6  
if(bFirst) |ZS 57c:  
{ 7%{R#$F  
nFileLength = getFileSize(); ^y:FjQC:  
if(nFileLength == -1) T?W[Z_D  
{ nqZA|-}  
System.err.println("File Length is not known!"); UppBnw  
} xj0cgK|!  
else if(nFileLength == -2)  Sa%zre@  
{ kP)YgkE  
System.err.println("File is not access!"); ANckv|&'v  
} 4rI:1yGt@  
else `@h:_d  
{ m_cO<LB  
for(int i=0;i<nStartPos.length;i++)  DZ^=*.  
{ X Y~;)<s_  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); .qSBh hH\  
} "Kyifw?  
for(int i=0;i<nEndPos.length-1;i++) ?QGm
oQ)  
{ %0vTA_W  
nEndPos = nStartPos[i+1]; d!`lsh@tF  
} )8[ym/m  
nEndPos[nEndPos.length-1] = nFileLength; Y.q>EUSH  
} o[o:A|n  
} >R(8/#|E  
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}ppVR$7]0  
//启动子线程 kGpV;F==*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]\OWZ{T'j  
for(int i=0;i<nStartPos.length;i++) W@l+ciZ_  
{ 3@&bxYXm  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o>2e!7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), c\M#5+1j  
nStartPos,nEndPos,i); ([Ebsj  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?8Et[tFg  
fileSplitterFetch.start(); wuKl-:S;Vs  
} mKV'jm0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1xz\=HOT  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `8,w[o oC2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", PfyRZ[3)c  
nEndPos = " + nFileLength); \ZS\i4  
// fileSplitterFetch[nPos.length-1].start(); w TlGJ$D0  
4RhR[  
+)gGs#2X  
//等待子线程结束 Wdo#?@m  
//int count = 0; (zY *0lN  
//是否结束while循环 ,~- ?l7  
boolean breakWhile = false; O7v]p  
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while(!bStop) oAY_sg+  
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write_nPos();
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Utility.sleep(500); i`+B4I8[  
breakWhile = true; ,*dzJT$k  
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for(int i=0;i<nStartPos.length;i++) vVAb'`ysv  
{ yIOLs}!SF  
if(!fileSplitterFetch.bDownOver) Uh.Sc:trA  
{ 9mQ#L<Ps  
breakWhile = false; vXb:  
break; $&IpX M]  
} z5 Bi=~=#  
} _Fizgs  
if(breakWhile) \83sSw  
break; ;W0]66&  
~n6[$WjZA  
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//count++; .jU Z  
//if(count>4) "<*awWNI  
// siteStop(); -u|l}}b
h  
} -l "U"U"F  
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System.err.println("文件下载结束！"); :M j_2  
} ^Gq5ig1rxy  
catch(Exception e){e.printStackTrace ();} 8%[HYgd5)  
} B;!f<"a8  
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//获得文件长度 Sj)}qM-y#  
public long getFileSize() :tM?%=Q  
{ b{RqwV5P  
int nFileLength = -1; ?U_9{}r  
try{ ~GG?GB  
URL url = new URL(siteInfoBean.getSSiteURL()); Gy!P,a)z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bD<qNqX$  
httpConnection.setRequestProperty("User-Agent","NetFox"); }E;F)=E  
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int responseCode=httpConnection.getResponseCode(); [9V
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if(responseCode>=400) BDe]18X  
{ C c*({  
processErrorCode(responseCode); HR60   
return -2; //-2 represent access is error `5'2Hg+  
} M$A
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String sHeader; Z)&D`RCf  
=-~;OH/  
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for(int i=1;;i++) (R'+j
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{ O"*`'D|hK  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ni6r{eS
Q  
//Utility.log(in.readLine()); TJaeQqob  
sHeader=httpConnection.getHeaderFieldKey(i); sS!w}o2X  
if(sHeader!=null) 6GYtY>  
{ ([ dT!B#aH  
if(sHeader.equals("Content-Length")) EfiU$8y  
{ \ZD[!w7  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); s&'BM~WI  
break; by86zX  
} ~O;y?]U  
} hazq#J!  
else @(:v_l  
break; hVP IHQt  
} alm- r-Kb3  
} 8$vK5Dnn8  
catch(IOException e){e.printStackTrace ();} `qiQ$kz  
catch(Exception e){e.printStackTrace ();} E=u/tpj  
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Utility.log(nFileLength); - 8bNQU  
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return nFileLength; k\N4@UK  
} A+ 
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//保存下载信息（文件指针位置） Lw*]EG|?  
private void write_nPos() )%Ru#}1X6  
{ C+%K6/J(  
try{ lIf(6nm@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^0tw%6:  
output.writeInt(nStartPos.length); KJh,,xI>by  
for(int i=0;i<nStartPos.length;i++) mm[SBiFO\  
{ dDtFx2(R  
// output.writeLong(nPos); 7=P^_LcU  
output.writeLong(fileSplitterFetch.nStartPos); t`|,6qEG  
output.writeLong(fileSplitterFetch.nEndPos); V U~Dk);Bv  
} $h28(K%  
output.close();  "0&N}  
} (/h5zCc/v  
catch(IOException e){e.printStackTrace ();} 'v&}(  
catch(Exception e){e.printStackTrace ();} S>Z|)I  
} 8
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//读取保存的下载信息（文件指针位置） -<N&0F4|*  
private void read_nPos() $%2H6Eg0  
{ /_\W+^
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try{ #cKqnk  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {6 .o=EyM{  
int nCount = input.readInt(); .px:e)iW  
nStartPos = new long[nCount]; KhaYr)&~  
nEndPos = new long[nCount]; o-eKAkh  
for(int i=0;i<nStartPos.length;i++) ^_>!B)  
{ Q\kub_I{@  
nStartPos = input.readLong();
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nEndPos = input.readLong(); V#83!
  
} +F@_Es<6  
input.close(); @CQb[!9C  
} rdJB*Rlkh  
catch(IOException e){e.printStackTrace ();} xiM&$<LpR  
catch(Exception e){e.printStackTrace ();} G&9#*<F$c  
} Bw<
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private void processErrorCode(int nErrorCode) lCb+{OB  
{ y79qwM.  
System.err.println("Error Code : " + nErrorCode); c-CYdi@  
} y' xF0  
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,&]MOe4@>  
//停止文件下载 '2^ Yw  
public void siteStop() 3071:W  
{ #DI$
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bStop = true; v[S-Pi1  
for(int i=0;i<nStartPos.length;i++) 'Ud|Ex@A9  
fileSplitterFetch.splitterStop(); jO'|mGUM  
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} svhrf;3:  
} hW2.8f$  
//负责部分文件的抓取 &M"ouy Zo9  
**FileSplitterFetch.java py<_HyJ  
*/ \
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package NetFox; n:#TOU1ix<  
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import java.io.*; *l>0t]5YH  
import java.net.*; [CN$ScK,  
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public class FileSplitterFetch extends Thread { _ PWj(});  
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String sURL; //File URL f3PMVf:<  
long nStartPos; //File Snippet Start Position z&+ zl6  
long nEndPos; //File Snippet End Position d;G~hVu  
int nThreadID; //Thread's ID H;KDZO9W  
boolean bDownOver = false; //Downing is over
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boolean bStop = false; //Stop identical B~gV'(9g  
FileAccessI fileAccessI = null; //File Access interface Z<z;L<tJ 9  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException eaZQ2  
{ 7'w0  
this.sURL = sURL; Q/^A #l[  
this.nStartPos = nStart; _p}xZD\?,  
this.nEndPos = nEnd; +m$5a YX  
nThreadID = id; #V_GOy1-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 VWf %v  
} /i
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public void run() cCdX0@hY  
{ }NmNanW^  
while(nStartPos < nEndPos && !bStop) V[hK2rVH.  
{ \,xFg w4  
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try{ Fi;VDK(V9  
URL url = new URL(sURL); g`,AaWlF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;Ss$2V'a  
httpConnection.setRequestProperty("User-Agent","NetFox"); r6.N4eW.L  
String sProperty = "bytes="+nStartPos+"-"; S`q%ypy  
httpConnection.setRequestProperty("RANGE",sProperty); "'tRfB  
Utility.log(sProperty); UH3t(o7O
 
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InputStream input = httpConnection.getInputStream(); ;5S}~+j  
//logResponseHead(httpConnection); 9'KonW  
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byte[] b = new byte[1024]; ecHP &Z$  
int nRead; Wk7WK` >i  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Fvl`2W94;  
{ h%}(h2W  
nStartPos += fileAccessI.write(b,0,nRead); ;u-4KK  
//if(nThreadID == 1) v.g"{us  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); k*$3i  
} trYTs,KV  
z'MS#6|}  
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Utility.log("Thread " + nThreadID + " is over!"); -T_\f?V88  
bDownOver = true; _j ;
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//nPos = fileAccessI.write (b,0,nRead); pB01J<@m  
} +"!aM?o  
catch(Exception e){e.printStackTrace ();} Fr:5$,At7-  
} Vz:_mKA  
} tk?UX7F  
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//打印回应的头信息 h=+$>_&:  
public void logResponseHead(HttpURLConnection con) ;=;JfNnbm  
{ ,0?!ov|  
for(int i=1;;i++)
q-AN[_@  
{ $k0H9_  
String header=con.getHeaderFieldKey(i); c@du2ICUc  
if(header!=null) bXdY\&fE  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 2@i;_
3sv  
Utility.log(header+" : "+con.getHeaderField(header)); cyF4iG'M,y  
else 3Sh+u>w  
break; _<Dt z  
} (JZ".En#X  
} l5O=V
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public void splitterStop() %$mjJw<|&  
{ kBsXfVs
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bStop = true; 49h0^;xlo:  
} ef
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} ?[= U%sPu=  
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ImkrV{,e  
/* oY3>UZ5\
  
**FileAccess.java 8T5k-HwE  
*//文件访问(定位，写) =_-C%<4  
package NetFox; :pZ}
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import java.io.*; `ggui
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public class FileAccessI implements Serializable{ aiux^V  
[.cq{6-
  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 O%JSViPw  
RandomAccessFile oSavedFile; t4K56H.L?  
long nPos; C0m\SNR  
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public FileAccessI() throws IOException k0ItG?C
v  
{ *\ECf.7jz  
this("",0); ExrY>*v  
} 6 =>G#  
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public FileAccessI(String sName,long nPos) throws IOException X"/~4\tJ"  
{ dWpk='  
oSavedFile = new RandomAccessFile(sName,"rw"); %z)EO9vtr  
this.nPos = nPos; J$[Q?8 ka  
oSavedFile.seek(nPos); nQLs<]h1  
} HeS'~Z$  
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public synchronized int write(byte[] b,int nStart,int nLen) rsxRk7s@  
{
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int n = -1; >t#\&|9I  
try{ p;->hn~D'5  
oSavedFile.write(b,nStart,nLen); 0dt"ZSm  
n = nLen; >oY^Gx  
} -c={+z "  
catch(IOException e) pVG>A&4  
{ W~dE  
e.printStackTrace (); T$c+m\j6  
} 8
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*m&&1W_  
return n; 4iBxPo(0  
} !~
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} gWu"91Y0>  
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/* uUS)#qM|  
**SiteInfoBean.java 4ftj>O  
*/ zoXuFg  
package NetFox; l1RlYl5  
`|,tCM&-  
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public class SiteInfoBean { FsY`nWwg  
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private String sSiteURL; //Site's URL e"_"vbk  
private String sFilePath; //Saved File's Path 9 z*(8d  
private String sFileName; //Saved File's Name 0w}{(P;  
private int nSplitter; //Count of Splited Downloading File ]h8/M7k  
L>:FGNf^H  
m X:bA5db  
public SiteInfoBean() S7#0*2#[o  
{//nSplitter的缺省值为5 cYD1~JX.  
//default value of nSplitter is 5 `~E<Sf<M  
this("","","",5); 5f3!NeI  
} *a4 b  
:SeLkQC  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) v>k b^38  
{ mxhW|}_-j  
sSiteURL= sURL; OfLM  
sFilePath = sPath; ]+,nA R  
sFileName = sName; 9OZ>y0)K~  
this.nSplitter = nSpiltter; *NjMb{[ZQ  
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} \S5V}!_  
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public String getSSiteURL() i ~P91  
{ cJV!>0ua  
return sSiteURL; ,whM22Af~{  
} qAvvXs=5  
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public void setSSiteURL(String value) l~{T#Q  
{ qL~Pjr>cF  
sSiteURL = value; /0!$p[cjm  
} v/(__xN`B  
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public String getSFilePath() i59k"pNm  
{ U)b&zZc;  
return sFilePath; T/Ez*iQW  
} h%|9]5(=  
4Xr"d@2(  
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public void setSFilePath(String value) nu(eLUU  
{ K1 6s)S'  
sFilePath = value; EK.c+Or,  
} r3?5'S`  
;
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public String getSFileName() 9XY|V<}  
{ "$4hv6 s  
return sFileName; GdL4|xv  
} B~e7w 4  
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public void setSFileName(String value) Ic_tc  
{ H8x:D3C0  
sFileName = value; 1=- X<M75  
} ap{{(y&R  
tTE3H_  
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public int getNSplitter() w7Pe  
{ _i#@t7  
return nSplitter; Mj,2\ijNM  
} e4?<GT  
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= c/3^e  
public void setNSplitter(int nCount) O]4W|WI3  
{ #SK#k<&P  
nSplitter = nCount; U8U/?zW/&  
} #{?m  
} R|6RI}  
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/* 
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**Utility.java _TV2)  
*/ upZYv~Sa  
package NetFox; / *Ou$  
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public class Utility { 0 [*nAo  
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*
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public Utility() $Cut  
{ ]5aux >.n  
}u38:(^`ai  
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} !Q<8c =f  
Fwg#d[:u  
//线程睡眠 !tm|A`<g#<  
public static void sleep(int nSecond) ZY~zpC_  
{ _D!M nTK  
try{ (mu{~@Hw  
Thread.sleep(nSecond); V;/ XG}M  
} w;z@py
  
catch(Exception e) WXRHG)nvL  
{ {[H4G,QK  
e.printStackTrace (); ~x76{.gT  
} #J'Z5)i|  
} hCSRsk3  
W ??;4  
//日志 2{jtQlc  
public static void log(String sMsg) *8pe<:A#p  
{ =k[(rvU3  
System.err.println(sMsg); ]
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ak  
} ])3lH%4-  
Q-H=wJ4R  
./aZ

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public static void log(int sMsg) Q;{D8 #!  
{ ?w c3+?\J  
System.err.println(sMsg); rPrEEWS0)  
} L|dab{9  
} WW,r9D:/  
\" 5F;J  
!nZI? z;  
/* a3DoLq"/  
**TestMethod.java bw<~R2[  
*/ GN}9$:  
package NetFox; 6x`\ J2x  
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R  
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public class TestMethod { Q&:92f\y  
=rs=8Ty?S  
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public TestMethod() H>@JfYZ0  
{ ///xx/weblogic60b2_win.exe "!w[U{  
try{ :7 s#5b  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); kV]%Q3t  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); FCjYTGA  
SiteFileFetch fileFetch = new SiteFileFetch(bean); h|$zHm  
fileFetch.start(); ; HR\R  
}  A[wxa
  
catch(Exception e){e.printStackTrace ();} [hvig$L  
&</@0  
C {H'  
} O23]!S<;  
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public static void main(String[] args) mt&JgA/  
{ uBd =x<c\  
new TestMethod(); v/4X[6(  
} E Ni%ge'":  
} ijR*5#5h  
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