http断点续传简单实现（java)

/* NF9fPAF%;  
**SiteFileFetch.java 3-^z<*  
*/ BCy# Td  
package NetFox; 7Aj o9  
import java.io.*; 
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import java.net.*; PHZ+u@AA6@  
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public class SiteFileFetch extends Thread { ~MuD`a7#G  
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SiteInfoBean siteInfoBean = null; //文件信息Bean A5U//y![{  
long[] nStartPos; //开始位置 S}QvG&c  
long[] nEndPos; //结束位置 \53(D7+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Ph{7S43  
long nFileLength; //文件长度 =v-qao7xCV  
boolean bFirst = true; //是否第一次取文件 ."HDUo2D7  
boolean bStop = false; //停止标志 E]T>m!6  
File tmpFile; //文件下载的临时信息 {, +,:w7  
DataOutputStream output; //输出到文件的输出流 zn!H&!8&  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &d5n_:^  
public SiteFileFetch(SiteInfoBean bean) throws IOException K=S-p3\g  
{ k9]M=eO  
siteInfoBean = bean; H]i.\2z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); bA/,{R  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /=o~7y  
if(tmpFile.exists ()) Pn&!C*,  
{ DjzHEqiH  
bFirst = false; H>
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read_nPos(); FBDRbJ su  
} F?h{IH f  
else hDPZj#(c  
{ >"Tivc5  
nStartPos = new long[bean.getNSplitter()]; -
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nEndPos = new long[bean.getNSplitter()]; tsGt,]O30  
} )(^L*  
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} %8U/!(.g  
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public void run() kfb*|  
{ 45?aV@  
//获得文件长度 'r/+za:2  
//分割文件 ]6)~Sj$ 5  
//实例FileSplitterFetch WR5@S&fU`  
//启动FileSplitterFetch线程 $9~6M*  
//等待子线程返回 H YA<  
try{ _BC%98:WP  
if(bFirst) Ln&'5D#  
{ )\xDo<@  
nFileLength = getFileSize(); >0^oC[ B  
if(nFileLength == -1) \:7G1_o  
{ n:TWZ.9  
System.err.println("File Length is not known!"); /"Z6\T9  
} Njp?/r  
else if(nFileLength == -2) O1C|{ M  
{ *#{V^}  
System.err.println("File is not access!");
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} u;@~P  
else s2IjZF{  
{ !L|}/u3v  
for(int i=0;i<nStartPos.length;i++) lla?;^,  
{ LtJl\m.th  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "W"
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} \ytF@"7  
for(int i=0;i<nEndPos.length-1;i++) NZ{)&ObBRt  
{ !@.9>"FU  
nEndPos = nStartPos[i+1]; 5*~]=(BE  
} PN(P$6
 
nEndPos[nEndPos.length-1] = nFileLength; 7{"urs7 T  
} VLL
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} pbXh}YJ&  
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//启动子线程 L lNd97Z  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Tgf\f%,h  
for(int i=0;i<nStartPos.length;i++) sYMgi D  
{ F"G]afI9+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), L\GjG&Y5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), mi`jY0e2  
nStartPos,nEndPos,i); `]T#uP<u  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zyHHz\{  
fileSplitterFetch.start(); 2#y-3y<G  
} Qp?+G~*  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [B2g{8{!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); CO<P$al  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", MS>QU@z7c  
nEndPos = " + nFileLength); 3EVAB0/$  
// fileSplitterFetch[nPos.length-1].start(); U8||)+  
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//等待子线程结束 1:.I0x!  
//int count = 0; ~uUN\qx52  
//是否结束while循环 j=],n8_i  
boolean breakWhile = false; Ra!Br6  
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while(!bStop) #Yd'Vve  
{ bE6:pGr  
write_nPos(); -zSkon2Y^  
Utility.sleep(500); &{
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breakWhile = true; l(B(gPvU  
 mS]&  
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for(int i=0;i<nStartPos.length;i++) 9f|+LN##  
{ TF[8r[93  
if(!fileSplitterFetch.bDownOver) A0A]#
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{ =N~*`5|rk  
breakWhile = false; }w|a^=HAp  
break; DwNEqHi  
} S.! n35  
} # fe%E.  
if(breakWhile) ^U8^P]{R|  
break; 0W6jF5T  
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//count++; !k}]`z^d  
//if(count>4) GKg&lM!O$  
// siteStop(); lx H3a :gm  
} [S:{$4&  
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System.err.println("文件下载结束！");  y
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} {gkY:$xnrG  
catch(Exception e){e.printStackTrace ();} 9sId2py]W  
} 8-_\Q2vG  
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//获得文件长度 oNFvRb2Rd  
public long getFileSize() a0
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{ n#dvBK0M  
int nFileLength = -1; voitdz  
try{ I #bta  
URL url = new URL(siteInfoBean.getSSiteURL()); J+:gIszsWT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); GU,ztO.w3  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?E6C|A$I  
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int responseCode=httpConnection.getResponseCode(); ] v8.ym  
if(responseCode>=400)
~2L]K4Z^  
{ ZDl6F`  
processErrorCode(responseCode); p|&9#?t4A  
return -2; //-2 represent access is error aBblP8)8;K  
} ?]/"AWUX  
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String sHeader; 6p)dO c3L  
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for(int i=1;;i++) F4|U\,g  
{ U^~jB= =]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); sqE? U*8.-  
//Utility.log(in.readLine()); ]N4?*S*jd)  
sHeader=httpConnection.getHeaderFieldKey(i); JIh:IR(ta  
if(sHeader!=null) ~}@cSv'(1  
{ ^)i1b:4  
if(sHeader.equals("Content-Length")) S uo  
{ XR@C^d  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8Ben}j)H  
break; "b `R_gG9  
} (O`2$~mIM  
} tGVC"a  
else %kXg|9Bx!  
break; c-".VF  
} 5m\T~[`%  
} +m]Kj3-z@  
catch(IOException e){e.printStackTrace ();} ;+NU;f/WM  
catch(Exception e){e.printStackTrace ();} fZNWJo# `.  
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Utility.log(nFileLength);
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return nFileLength; V'm4DR#M  
} Bf+7;4-  
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//保存下载信息（文件指针位置） [7sy}UH  
private void write_nPos() i286`SLU  
{ Q3P*&6wA  
try{ L>>Cx`ASi  
output = new DataOutputStream(new FileOutputStream(tmpFile));  M_ii  
output.writeInt(nStartPos.length); -j"]1JLQ  
for(int i=0;i<nStartPos.length;i++) qrt2BT)  
{ 6ntduXeNVh  
// output.writeLong(nPos); g|V
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output.writeLong(fileSplitterFetch.nStartPos); s;!Tz)  
output.writeLong(fileSplitterFetch.nEndPos); M_Z(+k{Gy  
} 8TV "9{ n  
output.close(); t/Y)%N  
} TD6MP9L  
catch(IOException e){e.printStackTrace ();} 9%6W_0>  
catch(Exception e){e.printStackTrace ();} QsC6\Gt#  
} ~Jlo>  
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//读取保存的下载信息（文件指针位置） ,HHCgN  
private void read_nPos() [)KLmL%  
{ #24eogo~  
try{ 4!)=!sL;  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); SQ0t28N3h  
int nCount = input.readInt(); OHyB
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nStartPos = new long[nCount]; a
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nEndPos = new long[nCount]; bUS"1Tg]*6  
for(int i=0;i<nStartPos.length;i++) d^W1;0  
{ ,,o5hD0V9  
nStartPos = input.readLong(); ie9,ye"  
nEndPos = input.readLong(); %K7wScz7  
} o'auCa,N  
input.close(); '3eL^Aq  
} lJ$j[Y  
catch(IOException e){e.printStackTrace ();} W&H
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catch(Exception e){e.printStackTrace ();} MF]EX  
} #[ZNiaWT  
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private void processErrorCode(int nErrorCode) AttS?TZr  
{ O=2SDuBZ  
System.err.println("Error Code : " + nErrorCode); l %M0^d6M  
} QxS=W2iN  
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//停止文件下载 ObIL
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public void siteStop() w/UZ6fu  
{ J_ y+.p- 5  
bStop = true; nBo?r}t4  
for(int i=0;i<nStartPos.length;i++) # @~HpqqR  
fileSplitterFetch.splitterStop(); qr|v|Ejd~  
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} @M_p3[c\  
} DSX.84  
//负责部分文件的抓取 #cdrobJ  
**FileSplitterFetch.java "B"Yfg[  
*/ ( {}Z '  
package NetFox; x
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import java.io.*; TOC2[mc'  
import java.net.*; ~&\}qz3  
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public class FileSplitterFetch extends Thread { VsR8|Hn$  
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String sURL; //File URL M>LgEc-v67  
long nStartPos; //File Snippet Start Position Vq>$ZlvS  
long nEndPos; //File Snippet End Position 4k4 d%  
int nThreadID; //Thread's ID h#o?O k  
boolean bDownOver = false; //Downing is over \[yg f6#[  
boolean bStop = false; //Stop identical DLBHZ?+!  
FileAccessI fileAccessI = null; //File Access interface C0v1x=(xiM  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException K#_x.:<J  
{ ecIZ+G)k  
this.sURL = sURL; & Y Y^Bd#  
this.nStartPos = nStart; !wNj;S
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this.nEndPos = nEnd; 'wm :Xa  
nThreadID = id; M`u&-6  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \!Cc[n(f#  
} !eE;MaS>  
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public void run() fqp!^-!X  
{ %ok??_}$}q  
while(nStartPos < nEndPos && !bStop) _G0_<WH6  
{ !${7)=|=1  
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try{ JDp{d c  
URL url = new URL(sURL); yMVlTO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;FfDi*S7  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3 jRI@  
String sProperty = "bytes="+nStartPos+"-"; K0xka[x=(  
httpConnection.setRequestProperty("RANGE",sProperty); YggeKN  
Utility.log(sProperty); &'KJh+jJ  
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InputStream input = httpConnection.getInputStream(); 'ugc=-0pd  
//logResponseHead(httpConnection); 0tb%h[%,M  
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byte[] b = new byte[1024]; t]14bf$*Q  
int nRead; IF~E;  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ZlG|U]mM5  
{ sDXD>upO  
nStartPos += fileAccessI.write(b,0,nRead); bbe$6xwi  
//if(nThreadID == 1) ta+MH
,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L5j%4BlK/  
} p()#+Xy  
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Utility.log("Thread " + nThreadID + " is over!"); `G0GWh)`x  
bDownOver = true; egXbe)ld  
//nPos = fileAccessI.write (b,0,nRead); :/<SJ({q  
} Q}6!t$Vk  
catch(Exception e){e.printStackTrace ();} 1O,:fTG<  
} u/_TR;u=q  
} "\`>Ll  
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//打印回应的头信息
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public void logResponseHead(HttpURLConnection con) bo|3sN+D  
{ w]O[{3"  
for(int i=1;;i++)
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{ ` G-V %  
String header=con.getHeaderFieldKey(i); >h3m/aeNC  
if(header!=null) scQnL'\  
//responseHeaders.put(header,httpConnection.getHeaderField(header));
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Utility.log(header+" : "+con.getHeaderField(header)); oT0TbZu%  
else Cno+rmsfT  
break; 1Wr,E#+C  
} Nbvs_>N  
} |w].*c}Z  
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public void splitterStop() h"3Mj*
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{ ;1AXu/  
bStop = true; m-u0U  
} H5!e/4iz  
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} YG_|L[/#  
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/* C2}f'  
**FileAccess.java 4H4ui&|7u6  
*//文件访问(定位，写) 7z;X@+O}s  
package NetFox; 3ZUME\U  
import java.io.*; q,m+W
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public class FileAccessI implements Serializable{ w<&R|= 93  
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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 ~YRG9TK  
RandomAccessFile oSavedFile; oH='\M%+  
long nPos; zQ~ax!}R  

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public FileAccessI() throws IOException 572{DC&T  
{ [nASMKK0  
this("",0); mgE r+  
} ).3riR  
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public FileAccessI(String sName,long nPos) throws IOException 4G2iT+X-  
{ Fs(FI\^  
oSavedFile = new RandomAccessFile(sName,"rw"); 0fzHEL  
this.nPos = nPos; ^D8~s;?  
oSavedFile.seek(nPos); p?2^JJpUb  
} hQ ?zc_3  
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public synchronized int write(byte[] b,int nStart,int nLen) s[bQO1g;*  
{ \IaUsx"#o{  
int n = -1; ZM16 ~k  
try{ $1 t IC_  
oSavedFile.write(b,nStart,nLen); Vbv)C3ezD  
n = nLen; i_(6}Y&  
} |=js!R|  
catch(IOException e) Ozg,6&3ji  
{ C2{*m{ D  
e.printStackTrace (); T5Iz{Ha  
} p1
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return n; m6uFmU*<M}  
} *#9?9SYSk  
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} ;pj,U!{%s\  
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/* hg2Ywzfm-  
**SiteInfoBean.java I0*N "07n  
*/ ~)pso7^:  
package NetFox; H<3:1*E  
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public class SiteInfoBean {  SQ&}18Z~  
@ZRg9M:N  
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private String sSiteURL; //Site's URL bFhZSk)  
private String sFilePath; //Saved File's Path "U!Vdt2vp  
private String sFileName; //Saved File's Name (8baa.ge  
private int nSplitter; //Count of Splited Downloading File EU7nS3K)O~  
:{ iK 5  
tA]u=-_h  
public SiteInfoBean() T|,/C|L  
{//nSplitter的缺省值为5 .W\JvPTC  
//default value of nSplitter is 5 $*`E;}S0  
this("","","",5); &NOCRabc  
} MOPHu O{^  
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k
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) fZoQQ[s  
{ :k-@w5(  
sSiteURL= sURL; _Wq;bKG  
sFilePath = sPath; x2TE[#><  
sFileName = sName; jvxCCYXR  
this.nSplitter = nSpiltter; &kcmkRRG  
R
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} \H&;.??W  
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public String getSSiteURL() 9oIfSr
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{ Sk:x.oOZ  
return sSiteURL; bI^F(  
} L1WvX6  
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public void setSSiteURL(String value) UoaWI2  
{ [kTckZv  
sSiteURL = value; D<:zw/IRE  
} K:A:3~I!NW  
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public String getSFilePath() (>,b5g  
{ E62_k 0q  
return sFilePath; XD" 4t4~>  
} @+1AYVz(k  
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public void setSFilePath(String value) 0dQ\Y]b  
{ ~T/tk?:8Vi  
sFilePath = value; O\gVB!x  
} &-w.rF@  
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public String getSFileName() C4GkFD   
{ ;.<HpDfG_  
return sFileName; C9_[ke[1D  
} xB]^^NYE=  
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public void setSFileName(String value) acgx')!c  
{  3bJ|L3G  
sFileName = value; I-=Ieq"R9  
} _k;HhLj`  
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public int getNSplitter() m=Gb<)Y  
{ tK?XU9o  
return nSplitter; [>U2!4=$M  
} p$ETAvD  
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public void setNSplitter(int nCount) +G\i$d;St  
{ K`j:F>b  
nSplitter = nCount; $~j9{*
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} IxG7eX!  
} W`P>vK@=  
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/* 5iI(A'R[7  
**Utility.java j,SZJ{ebXg  
*/ yqtaQ0F~  
package NetFox; :t;i2Ck  
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public class Utility { f*IvaY  
rZ)7(0BBs  
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public Utility() aR'~=t&;z1  
{ ori[[~OyB  
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} Sqyju3Yp  
;j[:tt\k  
//线程睡眠 g[uf e<  
public static void sleep(int nSecond) O(9*
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{ gjFQDrz(  
try{ Y*O Bky  
Thread.sleep(nSecond); 1_]%,  
} TJ>1?W\Z  
catch(Exception e) baL<|& c  
{ =P_*.SgR  
e.printStackTrace (); 94]i|2qj*  
} k*C[-5&#  
} 8rFP*K9  
`s3:Vsv4  
//日志 !&`\MD>;~R  
public static void log(String sMsg)
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{ G )`gn  
System.err.println(sMsg); W7@Vma`
 
} -}( o+!nl  
#JY>  
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public static void log(int sMsg) -j:yEZ4Oy  
{ )K`tnb.Pf  
System.err.println(sMsg); 4x?I,cAN  
} ~2yhZ  
} Fu\#:+5\  
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/* 1CM8P3  
**TestMethod.java O*x~a;?G  
*/ KoWG:~>|  
package NetFox; #`l&HV  
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public class TestMethod { ~r'ApeI9  
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@`Dh7Q  
public TestMethod() IG2z3(j  
{ ///xx/weblogic60b2_win.exe 86dz Jh  
try{ v6E5#pse8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -7o-d-d F  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ac966<
#  
SiteFileFetch fileFetch = new SiteFileFetch(bean); _\= /~>Xl  
fileFetch.start(); \5=4!Ez  
} gw%L M7yQR  
catch(Exception e){e.printStackTrace ();} klY
, @  
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} 'YYT1H)  
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">S1,rhgS  
public static void main(String[] args) `krVfE;_O  
{ 8YgRJQZ!  
new TestMethod(); &Fjyi"8(r  
} d-W*`:Q
 
} HqV4!o9'  
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