http断点续传简单实现（java)

/* y EfAa6  
**SiteFileFetch.java >W] Wc4\  
*/ y,`n9[$K\  
package NetFox; #X'-/q`.  
import java.io.*; t;VMtIW+E  
import java.net.*; _]o7iqtv  
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public class SiteFileFetch extends Thread { `oikSx$vB.  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ^-PYP:*  
long[] nStartPos; //开始位置 &%j`WF4p  
long[] nEndPos; //结束位置 qzxWv5UH  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 5l8F.LtO\  
long nFileLength; //文件长度 `PtB2,?  
boolean bFirst = true; //是否第一次取文件 e_epuki  
boolean bStop = false; //停止标志 153*b^iDBh  
File tmpFile; //文件下载的临时信息 cI8\d 4/py  
DataOutputStream output; //输出到文件的输出流 ,^c-}`!K  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 9?ll(5E  
public SiteFileFetch(SiteInfoBean bean) throws IOException V)~b+D  
{ >g!$H}\  
siteInfoBean = bean; A2\hmp@A@7  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %1k"K~eu  
if(tmpFile.exists ()) `Z>=5:+G@2  
{ h='&^1  
bFirst = false; ]Whv%  
read_nPos(); 2 oL$I(83  
} t&43)TPb.  
else a] c03$fK  
{ B]yO  
nStartPos = new long[bean.getNSplitter()]; OjffN'a+N  
nEndPos = new long[bean.getNSplitter()]; -2}ons(  
} X{cB%to  
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} (kX:@9Pn  
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public void run() fGeie m  
{ Fg p|gw4  
//获得文件长度 eVMnI yr  
//分割文件 $HOe){G  
//实例FileSplitterFetch J(]b1
e  
//启动FileSplitterFetch线程 e@O]c"  
//等待子线程返回 g51UIN]o-  
try{ 6X'0 T}  
if(bFirst) p<D@l2vt  
{ KIY`3Fl09  
nFileLength = getFileSize(); fA1{-JzV<4  
if(nFileLength == -1) GK6~~ga=  
{ ?vWF[ DRd'  
System.err.println("File Length is not known!"); X<Xiva85  
} >u0XV"g$  
else if(nFileLength == -2) M).CyY;bm  
{ 'HV@i)h0%V  
System.err.println("File is not access!"); }vP
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} h~%8p ]  
else ^pY8'LF6  
{ @v&P;=lU  
for(int i=0;i<nStartPos.length;i++) }3WP:E
t  
{ op-\|<i  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); eFy {VpO+  
} <h+UC# .x  
for(int i=0;i<nEndPos.length-1;i++) ntPX?/  
{ @+Nf@LJ  
nEndPos = nStartPos[i+1]; qM3NQ8Rm  
} T_wh)B4xW  
nEndPos[nEndPos.length-1] = nFileLength; >ZgV8X:  
} @!ja/Y^  
} 'Zex/:QS  
B )\;Ja  
NTK9`#SA  
//启动子线程 ($UUgjv F  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; G"L`9E<0V  
for(int i=0;i<nStartPos.length;i++) O\=Zo9(NHF  
{ 5mL4Zq"  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w4Hq|N1-Y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), kbH@h2Ww  
nStartPos,nEndPos,i); +_*iF5\  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); PN J&{4wY  
fileSplitterFetch.start(); x{G 'IEf  
} Ks^wX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3)e{{]6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); TZg1,Z  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !"E/6z2&(k  
nEndPos = " + nFileLength); 9@Cu5U]  
// fileSplitterFetch[nPos.length-1].start(); $Dv5TUKw  
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^e\$g2)
.  
//等待子线程结束 "?iyvzo  
//int count = 0; .Tw:Y,G  
//是否结束while循环 %SCt_9u  
boolean breakWhile = false; y La E]  
#l9sQ-1Q  
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while(!bStop) rY@9nQ\>g  
{ Zrgv*  
write_nPos(); +.rOqkxJ  
Utility.sleep(500); k3Pu
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breakWhile = true; @li/Y6Wh  
R7h3O0@!  
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for(int i=0;i<nStartPos.length;i++) ru1^.(W2  
{ [P}mDX  
if(!fileSplitterFetch.bDownOver) 7&]|c?([4  
{ S {+Z.P  
breakWhile = false; el2<W=^M  
break; &U([Wd?E2  
} BbL]0i  
} GZuWAa  
if(breakWhile) BT$Oh4y4  
break; 3U!=R-  
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~oK0k_{~  
//count++; B:cQsaty  
//if(count>4) F$:UvW@e1  
// siteStop(); DqmKDU  
} v:w^$]4  
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System.err.println("文件下载结束！"); ~*^o[~x]\  
} |(,{&\  
catch(Exception e){e.printStackTrace ();} 6p3cMJ'8y  
} +^AAik<yl  
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//获得文件长度 ;K4uu<e\  
public long getFileSize() ]
ab q$
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{ _)YB
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int nFileLength = -1;  (wxi!  
try{ jJ'NYG  
URL url = new URL(siteInfoBean.getSSiteURL()); L`9.Gf  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); mjk<FXW  
httpConnection.setRequestProperty("User-Agent","NetFox"); cbzS7q<)  
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6  
int responseCode=httpConnection.getResponseCode(); DPmY_[OAE  
if(responseCode>=400) j>.1RG  
{ F/:%YR;  
processErrorCode(responseCode); t!B,%,Dp  
return -2; //-2 represent access is error 8A-*MU`+  
} m?8o\|i,  
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String sHeader; \-[ >bsg  
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for(int i=1;;i++) ]xJ.OUJy  
{ :eevc7  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A\E ))b9+  
//Utility.log(in.readLine()); ]ZI@?H? O  
sHeader=httpConnection.getHeaderFieldKey(i); ]j$(so"  
if(sHeader!=null) [I<J6=  
{ ^\yz`b(A0  
if(sHeader.equals("Content-Length")) Df(+@L5!  
{ I@#IXH?6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); <KoOJMx(  
break; CqU^bVs  
} K;w]sN+I  
} `v2Xp3o4f  
else #60gjHYaV  
break; M}=>~TA@  
} Y\4B2:Qd9  
} :}gEt?TUhs  
catch(IOException e){e.printStackTrace ();} (FGHt/!  
catch(Exception e){e.printStackTrace ();} taO(\FOm  
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Utility.log(nFileLength); 5EECr \*  
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return nFileLength; \uJ+~db
=  
} rD !GEU
 
q; C6ID`  
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//保存下载信息（文件指针位置） j|XL$Q  
private void write_nPos() J*Cf1 D5!  
{ sx'eu;S  
try{ vCOtED*<  
output = new DataOutputStream(new FileOutputStream(tmpFile)); $Ny:At  
output.writeInt(nStartPos.length); ^D ;EbR  
for(int i=0;i<nStartPos.length;i++) KYz@H#M  
{ QDKY7"H  
// output.writeLong(nPos); y!q`o$nK  
output.writeLong(fileSplitterFetch.nStartPos); k
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output.writeLong(fileSplitterFetch.nEndPos); zp``e;gY  
} _|;{{8*?  
output.close(); MfdkvJ'  
} Ev3,p`zS._  
catch(IOException e){e.printStackTrace ();} 4VC8#x1  
catch(Exception e){e.printStackTrace ();} kD)]\  
} ^7=h%{>=  
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//读取保存的下载信息（文件指针位置） s'Qmrs a  
private void read_nPos() T!^v^m@>y  
{ "x 3C3Zu.;  
try{ = U[$i"+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !lM.1gTTC  
int nCount = input.readInt(); OgHqF,0MN  
nStartPos = new long[nCount]; 8~|v:qk  
nEndPos = new long[nCount]; J]Rh+@r.  
for(int i=0;i<nStartPos.length;i++) xokA_3,1F  
{ Q"3gvIyc  
nStartPos = input.readLong(); OXB 5W#$  
nEndPos = input.readLong(); E[BM0.#bZ  
} |A+,M"F?  
input.close(); S5YEz XG  
} Kp;a(D  
catch(IOException e){e.printStackTrace ();} TJZarNc$  
catch(Exception e){e.printStackTrace ();} `f<w+u  
} V`1x!
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private void processErrorCode(int nErrorCode) XK;Vu#E*^  
{ QC6QqcOX  
System.err.println("Error Code : " + nErrorCode); Tz0XBH_  
} V=YDqof  
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//停止文件下载 @CoUFdbz  
public void siteStop() {CFy %  
{ "_=t1UE  
bStop = true; *&V"x=ba,  
for(int i=0;i<nStartPos.length;i++) 9Sl5jn  
fileSplitterFetch.splitterStop(); $FZcvo3@*S  
+6^hp-G7  
7I;0%sVQ{  
} BA8!NR|  
} Zcg-i:@  
//负责部分文件的抓取 nHU}OGzW  
**FileSplitterFetch.java kxmsrQ
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*/ 8Au W>7_  
package NetFox; h${=gSJc  
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import java.io.*; fwa*|y;  
import java.net.*; ;*d?Qe:  
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V  
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public class FileSplitterFetch extends Thread { nB/`~_9  
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String sURL; //File URL Ix~rBD9  
long nStartPos; //File Snippet Start Position iRM ?_
|  
long nEndPos; //File Snippet End Position 1O1MB&5%  
int nThreadID; //Thread's ID Qtt3;5m  
boolean bDownOver = false; //Downing is over kovJ
9  
boolean bStop = false; //Stop identical p[;@9!t  
FileAccessI fileAccessI = null; //File Access interface hZ')<@hNP  
$yUPua/-  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Zq:c2/\c}  
{ #IJ6pg>K  
this.sURL = sURL; c(!pcB8  
this.nStartPos = nStart; 8?w#=@s  
this.nEndPos = nEnd; t Q.%f:|  
nThreadID = id; o)'06FF\$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 R?Ch8mW.!  
} |EY1$qItid  
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public void run() j@4]0o  
{ >GmO8dK  
while(nStartPos < nEndPos && !bStop) M} +s_h
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{ J?1Eh14KZ  
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try{ a%QgL&_5  
URL url = new URL(sURL); c2]h.G83  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *T.V5FB0S  
httpConnection.setRequestProperty("User-Agent","NetFox"); O@skd2  
String sProperty = "bytes="+nStartPos+"-"; s~c cx"HH  
httpConnection.setRequestProperty("RANGE",sProperty); }
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Utility.log(sProperty); ?ea5k*#a  
-oY8]HrXfK  
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InputStream input = httpConnection.getInputStream(); c4bvJy8  
//logResponseHead(httpConnection); PK&X
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byte[] b = new byte[1024]; >xXq:4l>}  
int nRead; SjcX|=S  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ZbH_h]1$D  
{ :J+ANIRI  
nStartPos += fileAccessI.write(b,0,nRead); l>("L9  
//if(nThreadID == 1) :]LW,Eql  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); QHtN_
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} E_{P^7Z|Jg  
TjpAJW@-  
:\%hv>}|  
Utility.log("Thread " + nThreadID + " is over!"); r>rL[`p(2  
bDownOver = true; 7}(YCZny5  
//nPos = fileAccessI.write (b,0,nRead); }$* z:E  
} sBNqg~HwB?  
catch(Exception e){e.printStackTrace ();} z*o2jz?t4  
} ~$1g"jIw  
} T7
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//打印回应的头信息 {RD9j1  
public void logResponseHead(HttpURLConnection con) K
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{ %mOQIXr1s  
for(int i=1;;i++) _
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{ eGWwPSIp  
String header=con.getHeaderFieldKey(i); {9~3y2:  
if(header!=null) 59V8cO+qH  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); tnq ZlS  
Utility.log(header+" : "+con.getHeaderField(header)); T6\d]  
else 4OG1_6K  
break; <B+ WM  
} K'[kl'  
} s2#}@b6'.  
+77j2W_0  
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public void splitterStop() cxIAI=JK  
{ HYNpvK  
bStop = true; xzf/W+.>.  
} ayN[y  
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} WHRBYq_  
;rXZ?"  
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/* ];u nR<H  
**FileAccess.java 6-\M }xq?  
*//文件访问(定位，写) j<h0`v  
package NetFox; +t(Gt0+  
import java.io.*; JRDIGS_~  
6)~7Uf:<v  
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public class FileAccessI implements Serializable{ TR:4$92:H  
{=+'3p  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 [MeFj!(  
RandomAccessFile oSavedFile; mqiCn]8G  
long nPos; _ujhD  
e`?o`@vO,  
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public FileAccessI() throws IOException n9k-OGJ  
{ >{"E~U  
this("",0); q oz[x  
} %'Z`425a  
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public FileAccessI(String sName,long nPos) throws IOException 3WPZZN<K9  
{ _F2ofB'  
oSavedFile = new RandomAccessFile(sName,"rw"); 48.4GwL7  
this.nPos = nPos; ]5e|W Q>*X  
oSavedFile.seek(nPos); .F0Q<s9  
} #eKH'fE  
p }3$7CR/  
+]e) :J  
public synchronized int write(byte[] b,int nStart,int nLen) <#
)Q.P  
{ iz27yXHZ~  
int n = -1; ^a7a_M  
try{ 5GURfG3{  
oSavedFile.write(b,nStart,nLen); R'^J#"[  
n = nLen; u/J1Z>0  
} HHT8_c'CC#  
catch(IOException e) z
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{ {@[#0gPH  
e.printStackTrace (); GGsAisF"N  
} K#R|GEwr  
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return n; ,2mq}u>WU  
} D=M'g}l  
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} b{.Y?.U  
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5 axt\  
/* i({MID)/_  
**SiteInfoBean.java _D8:p>=  
*/ D&D-E~b^  
package NetFox; LKg9{0Y:  
">q?(i\  
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public class SiteInfoBean { Nh^q&[?  
)!'7!" $  
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private String sSiteURL; //Site's URL Xvxrz{  
private String sFilePath; //Saved File's Path )IKqO:@  
private String sFileName; //Saved File's Name CW,|l0i  
private int nSplitter; //Count of Splited Downloading File 03!#99  
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public SiteInfoBean() L8KaK  
{//nSplitter的缺省值为5 )O>M~  
//default value of nSplitter is 5 ',I$`h  
this("","","",5); \\Nt^j3qR  
} 5oo6d4[  
pAyUQe;X#  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) G9CL}=lJ,  
{ QfL8@W~e  
sSiteURL= sURL; x)f<lZ^L&H  
sFilePath = sPath; <4N E)!#  
sFileName = sName; q'%!qa+  
this.nSplitter = nSpiltter; n`p/;D=?  
u\
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} tD]vx`0>  
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public String getSSiteURL() Rj-4K@a8#N  
{ 0kaMYV?  
return sSiteURL; |lh&l<=(f  
} /km0[M  
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@`
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public void setSSiteURL(String value) $Y%,?>AL<  
{ ;kD Rm'(  
sSiteURL = value; unyU|B  
}
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public String getSFilePath()
&& WEBQ  
{ 'fY29Xr^  
return sFilePath; Jv~^hN2  
} $Eo-58<q  
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`Nv7c{M^  
public void setSFilePath(String value) }q:4Zh'l!  
{  mEbj  
sFilePath = value; vP,$S^7$  
} yRt7&,}zL  
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OOzXA%<%c  
public String getSFileName() 66scBi_d  
{ {G{>Qa|  
return sFileName; iT</  
} {Bb:\N8X  
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c=p!2jJ1K~  
public void setSFileName(String value) %ejq|i7  
{ _B
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sFileName = value; )&ucX  
} L!~ap  
SxL/]jWR7  
:13u{5:th  
public int getNSplitter() V/yj.aA*@  
{ Sea6xGdq  
return nSplitter; Nu+DVIM  
} z]!w@:  
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A
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public void setNSplitter(int nCount) +(h{3Y|  
{ $rPQ%2eF4  
nSplitter = nCount; 9yj'->dL  
} XjTu`?Na;  
} ~\ v"xV  
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q<4{&omUJ  
/* "lL/OmG  
**Utility.java rW`l1yi*$  
*/ Xi!e=5&Pa  
package NetFox; ~Sx\>wBlc  
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public class Utility { a?*pO`<J{  
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40 zO4  
public Utility() mcxD#+H 3  
{
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7nZ3u_~  
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} \Npvm49  
SA?1*dw)  
//线程睡眠 =D)ADZ\<r  
public static void sleep(int nSecond) T2|os{U  
{ T/jxsIt3  
try{ y8dOx=c  
Thread.sleep(nSecond); -:Bgp*S  
} Asj<u!L  
catch(Exception e) |Gr@Mi5  
{ lz_ r  
e.printStackTrace (); )*aAkM  
} _AH_<Z(  
} ^grDP*;W  
kkXe=f%  
//日志 =
]1g*~%  
public static void log(String sMsg) :c(#03w*C  
{ LVdtI  
System.err.println(sMsg); 3A\Z]L  
} a>k9& w  
N]&hw&R{Q  
$_gv(&ZT  
public static void log(int sMsg) (R(NEN  
{ )M8@|~~  
System.err.println(sMsg); vgi`.hk  
} )))AxgM  
} S(lqj6aa}  
qBZ;S3  
kRH D{6mol  
/* 5Hs!s+  
**TestMethod.java v+CW([zAx#  
*/ &?k`rF9  
package NetFox; GE\({V.W  
^UyN)eX  
ML%JTx0+Z  
public class TestMethod { muO;g&  
p$<){,R  
7r pTk&`  
public TestMethod() FV%|*JW[;N  
{ ///xx/weblogic60b2_win.exe Vc+~yh.)  
try{ jI$7vmO  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); w<I
q:3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); U[:Js@uH_  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >uE<-klv  
fileFetch.start(); {(h!JeQ  
} h{ eQ\iI  
catch(Exception e){e.printStackTrace ();} |^#Z!Hp_Y  
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} s*vtCdrE.  
#:
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public static void main(String[] args) =HMuAUa.  
{ #*G}v%Ow/u  
new TestMethod(); 4hUUQ;xj  
} M$3/jl*#}  
} =BzBM`
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