http断点续传简单实现（java)

/* <4{m99  
**SiteFileFetch.java OvH:3"Sdy  
*/ Zo UeLU  
package NetFox; # epP~J_f  
import java.io.*; wv~:^v'  
import java.net.*; @Y0
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public class SiteFileFetch extends Thread { Wh
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SiteInfoBean siteInfoBean = null; //文件信息Bean j"Jf|Hq $  
long[] nStartPos; //开始位置 |E~c#lV  
long[] nEndPos; //结束位置 mG)5xD  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [G 9Pb)  
long nFileLength; //文件长度 wx-\@{E  
boolean bFirst = true; //是否第一次取文件 k26C=tlkv"  
boolean bStop = false; //停止标志 stiF`l  
File tmpFile; //文件下载的临时信息 RvG=GJJ9  
DataOutputStream output; //输出到文件的输出流 EPE_2a}  
j_C"O,WS  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Nuqmp7C  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?}`-?JB1  
{ c0wLc,)G  
siteInfoBean = bean; y\v#qFVOZ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ~\=D@G,9  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); l8~(bq1  
if(tmpFile.exists ()) izSX  
{ cGm3LS6]*  
bFirst = false; Z/,R{Jgt"  
read_nPos(); #91^1jyMf  
} %P}H3;2  
else %OoH<\w w  
{ b5MBzFw  
nStartPos = new long[bean.getNSplitter()]; h6k" D4o\  
nEndPos = new long[bean.getNSplitter()]; DN:| s+Lz  
} {Q>OZm\+  
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} J0V m&TY  
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public void run() zgY VB
}  
{ nlpEkq  
//获得文件长度 xVB rwkk(  
//分割文件 "U^m~N9k{  
//实例FileSplitterFetch #E+ybwA  
//启动FileSplitterFetch线程 @QTw9,pS  
//等待子线程返回 `M~R4lr  
try{ :G>w MMv&z  
if(bFirst) I^EZ
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{ =r+K2]z,L  
nFileLength = getFileSize(); x8aOXN#w}  
if(nFileLength == -1) LZ wCe$1  
{ yH(
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System.err.println("File Length is not known!"); wa<k%_# M  
} 3qTr|8`s  
else if(nFileLength == -2) t U}6^yc  
{ 4Q!A w  
System.err.println("File is not access!"); kNK0KL  
} 7c"Csq/]I  
else u7mPp3ZYK  
{ 5r)8MklZ  
for(int i=0;i<nStartPos.length;i++) U
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{ ]I)ofXu]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); aX1b(h2  
} umns*U%T;  
for(int i=0;i<nEndPos.length-1;i++) $y6 <2w%b  
{ {,JO}Dmu5  
nEndPos = nStartPos[i+1]; rmzzbLTu  
} H2%Qu<Kg2  
nEndPos[nEndPos.length-1] = nFileLength; *VhEl7  
} f~wON>$K  
} %B\x %e;P  
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//启动子线程 _|["}M"?  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ss%,  
for(int i=0;i<nStartPos.length;i++) pWKE`x^  
{ WfaMu| L  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9[zxq`qT}+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), A0Nx?  
nStartPos,nEndPos,i); *gH]R*Q[Rt  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^O*-|ecA  
fileSplitterFetch.start(); tnobqL'  
} iGSJ\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), dscah0T  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); H2BRId  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -y|J_;EG  
nEndPos = " + nFileLength); )XN%pn  
// fileSplitterFetch[nPos.length-1].start(); -B#1+rUW  
9no<;1+j,  

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//等待子线程结束 E>s+"y  
//int count = 0; zQulPU  
//是否结束while循环 >fWGiFmlk  
boolean breakWhile = false; 3!l>\#q6  
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while(!bStop) (*$F7oO<  
{ 2pdeJ  
write_nPos(); 6}-No  
Utility.sleep(500); |\Jnr3)  
breakWhile = true; KV$&qM.  
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for(int i=0;i<nStartPos.length;i++) s0dP3tz>  
{ ,Tr&`2w  
if(!fileSplitterFetch.bDownOver) 3`yO&upk  
{ kyAN O  
breakWhile = false; xH\\#4/  
break; ]S4"JcM  
} I :<,9.   
} xg/(  
if(breakWhile) .4^+q9M  
break; _aevaWtEx  
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//count++; 5(ZOm|3ix  
//if(count>4) kVQm|frUz  
// siteStop(); Ztmh z_u7  
} =!q]0#  
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System.err.println("文件下载结束！"); 7JBs7L
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} aC[G_ACwc  
catch(Exception e){e.printStackTrace ();} cxs@ph&Wk  
} $B-/>Rz  
0RA#Y(IR  
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//获得文件长度 L@GICW~  
public long getFileSize() uX_#NP/2  
{ v_5qE  
int nFileLength = -1; #aL.E(%  
try{ b5)^g+8)w  
URL url = new URL(siteInfoBean.getSSiteURL()); #ae?#?/"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w>j5oz}  
httpConnection.setRequestProperty("User-Agent","NetFox"); jdG2u p  
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int responseCode=httpConnection.getResponseCode(); Eh8GqFEM  
if(responseCode>=400) Oh1U=V2~  
{ 6Sd:5eTEQ  
processErrorCode(responseCode); 5Jo'h]  
return -2; //-2 represent access is error m+'1c}n^7  
} -lJ|x>PG'  
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;>Z+b#C[  
String sHeader; XA#qBxp/h  
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for(int i=1;;i++) LmJjO:W}^y  
{ ~$6`
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); :epBd3f  
//Utility.log(in.readLine()); <~uzHg%Y  
sHeader=httpConnection.getHeaderFieldKey(i); >bV3~m$a+  
if(sHeader!=null) \m|5Aqs  
{ vxPE=!|  
if(sHeader.equals("Content-Length"))  it H  
{ @I4HpY
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); F'[Y.tA ,#  
break; LA
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} d3rjj4N"z  
} c\ZI 5&4jT  
else #WG}"[ ,c  
break; E'{:HX  
} ]mtiIu[  
} Fy5:|CN  
catch(IOException e){e.printStackTrace ();} )8^E{w^D}  
catch(Exception e){e.printStackTrace ();} MRz f#o<H  
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Utility.log(nFileLength); Ec<33i]h*p  
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return nFileLength; f`ibP6%  
} mxCneX  
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//保存下载信息（文件指针位置） k 76<CX  
private void write_nPos() CP9Q|'oJ  
{ u^SInanw  
try{ C1f$^
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output = new DataOutputStream(new FileOutputStream(tmpFile)); W[I[Xg&  
output.writeInt(nStartPos.length); Q3i\`-kbb  
for(int i=0;i<nStartPos.length;i++) R(0[bMr3Q  
{ *P\lzM  
// output.writeLong(nPos); Zq33R`  
output.writeLong(fileSplitterFetch.nStartPos); a:*N0  
output.writeLong(fileSplitterFetch.nEndPos); yH:p*|%:  
} ih)\P0wed  
output.close(); >{Ayzz>v  
} 1^]IuPxq  
catch(IOException e){e.printStackTrace ();} N}/V2K]Q  
catch(Exception e){e.printStackTrace ();} lPz`?Hn  
} ]lKUpsQI  
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;  
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//读取保存的下载信息（文件指针位置） mN{H^  
private void read_nPos() zfDfy!\2_  
{ el$@^Wy&$  
try{ ZL0Vx6Ph  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 38-kl,Vw  
int nCount = input.readInt(); @>VX]Qe^X  
nStartPos = new long[nCount]; 5I[:.o0  
nEndPos = new long[nCount]; }#.OJub  
for(int i=0;i<nStartPos.length;i++) MjQ>&fUK  
{ 6miXaAA8  
nStartPos = input.readLong(); xr.;B`T0\'  
nEndPos = input.readLong(); :KC]1_zqR  
} x Y$x=)  
input.close(); 5hEA/G  
} ,^ ,R .T  
catch(IOException e){e.printStackTrace ();} m~=VUhPd  
catch(Exception e){e.printStackTrace ();} B7qi|Fw  
} 1Bs t|  
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private void processErrorCode(int nErrorCode) ,]JIp~=nsh  
{ J0bcW25  
System.err.println("Error Code : " + nErrorCode); 0u"j^v  
} tol-PJS}  
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\5N\NN @J  
//停止文件下载 bhDqRM  
public void siteStop() g'km*EV  
{ !b0A%1W;  
bStop = true; ~~WY?I-  
for(int i=0;i<nStartPos.length;i++) '%e@7Cs  
fileSplitterFetch.splitterStop(); FDF DB  
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} %t* 9sh  
} JI-.SR  
//负责部分文件的抓取 AWFq5YMSI  
**FileSplitterFetch.java I^LU*A=  
*/ V`/c#y||  
package NetFox; D)4#AI  
n|.eL8lX.<  
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import java.io.*; [KGj70|~  
import java.net.*; \{*`-Pv  
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public class FileSplitterFetch extends Thread { lM
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String sURL; //File URL p;zT #%  
long nStartPos; //File Snippet Start Position It'kO jx]  
long nEndPos; //File Snippet End Position ]GHw~s?  
int nThreadID; //Thread's ID !6taOT>v  
boolean bDownOver = false; //Downing is over s 64@<oU<"  
boolean bStop = false; //Stop identical xG4 C 6s  
FileAccessI fileAccessI = null; //File Access interface 2GigeN|1N  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Tsu\4 cL]  
{ /i!/)]*-  
this.sURL = sURL; u1'l4VgT  
this.nStartPos = nStart; Wxj(3lg/  
this.nEndPos = nEnd; Wl&6T1A`"  
nThreadID = id; +sZY0(|K8  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 FD~uUZTM  
} ze8MFz'm  
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public void run() Y!c7P,cZ+3  
{ `} 'o2oZnG  
while(nStartPos < nEndPos && !bStop) FFVh~em{  
{ Xa'b@*o&  
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try{ xOxyz6B\  
URL url = new URL(sURL); +
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Qdc#v\B  
httpConnection.setRequestProperty("User-Agent","NetFox"); h|z59h&X8G  
String sProperty = "bytes="+nStartPos+"-"; 2xy{g&G
 
httpConnection.setRequestProperty("RANGE",sProperty); G!F_Q7|-  
Utility.log(sProperty); K.?S,qg  
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InputStream input = httpConnection.getInputStream(); sx[mbKj<  
//logResponseHead(httpConnection); ZI :wJU:f  
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byte[] b = new byte[1024]; `ST;";7!  
int nRead; N4yQ,tG>aa  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |BbrB[+ v[  
{ apxq] ! `  
nStartPos += fileAccessI.write(b,0,nRead); U6nC <3f F  
//if(nThreadID == 1) KAT^vbR  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Hnvs{KC`  
} o(i?_4E  
/T&+vzCF  
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Utility.log("Thread " + nThreadID + " is over!"); a\MJh+K  
bDownOver = true; Hs.5@l  
//nPos = fileAccessI.write (b,0,nRead); q"g4fzCD  
} .'1]2/ad  
catch(Exception e){e.printStackTrace ();} O~Dm|hP  
} 1$yS
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} 2+YM .Zl  
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|' kC9H[>  
//打印回应的头信息 SV1;[  
public void logResponseHead(HttpURLConnection con) LwI4 2  
{ P=4o)e7E!  
for(int i=1;;i++) t.XuH#  
{ 7c'OIY].,  
String header=con.getHeaderFieldKey(i); y8di-d3_  
if(header!=null) ;ejtP #$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); j{%'A  
Utility.log(header+" : "+con.getHeaderField(header)); 8;,(D#p  
else y 0fI7:e3  
break; nhq,Y0YH  
} eGrxS;NY  
} Xr|e%]!**  
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public void splitterStop() c#[d7t8ONe  
{ a&n}pnEn)  
bStop = true; hy
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} Eds{-x|10  
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} 1u~.^O}J  
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/* ?trqe/  
**FileAccess.java 2C&l\16  
*//文件访问(定位，写) MOP#to)k&  
package NetFox; Oufdi3
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import java.io.*; G8hDR^ra  
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public class FileAccessI implements Serializable{ }/-TT0*6j<  
4d @ (>  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Si[xyG6=  
RandomAccessFile oSavedFile; sCRmLUD  
long nPos; nTXM/  
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public FileAccessI() throws IOException - z"D_5  
{ CEb al\R  
this("",0); [yfi:|n1  
} .:+&2#b  
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public FileAccessI(String sName,long nPos) throws IOException e^Lt{/  
{ Z<Ke/Xi  
oSavedFile = new RandomAccessFile(sName,"rw"); -MH~1Tw6Z  
this.nPos = nPos; JlN<w  
oSavedFile.seek(nPos); P}C;%KzA  
} d"4J)+q  
x4bj?=+  
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public synchronized int write(byte[] b,int nStart,int nLen) R4g% $}  
{ .R>4'#8q  
int n = -1; SAw. 6<Wy-  
try{ _0]{kB.$_  
oSavedFile.write(b,nStart,nLen); aY
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n = nLen; =^A/&[&31  
} lCMU{)  
catch(IOException e) 4XL]~3 c  
{ :raYt5n1,y  
e.printStackTrace (); -&\?Q_6  
} vT>ki0P_;  
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return n; {:r8X  
} $f^ \fa[  
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} R@)L@M)u;  
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/* ?u]%T]W  
**SiteInfoBean.java 5+[`x']l  
*/ K6Gri>Um  
package NetFox; 'cx&:s  
f}1R,N_fC  
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public class SiteInfoBean { AK*F,H9  
]M;aVw<!  
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private String sSiteURL; //Site's URL qs]7S^yw  
private String sFilePath; //Saved File's Path ?u9JRXj%  
private String sFileName; //Saved File's Name &_EjP hZ  
private int nSplitter; //Count of Splited Downloading File okO^/"  
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public SiteInfoBean() *MEDV1l_T  
{//nSplitter的缺省值为5 W1 qE,%
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//default value of nSplitter is 5 )"IBw0]  
this("","","",5); k-b0Eogp]  
} A:3:Cr  
.7*3V6h=F  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 9cu0$P`}5  
{ =2z9Aq{  
sSiteURL= sURL; ? D?XaRb  
sFilePath = sPath; av&4:O!  
sFileName = sName; _O-ZII~  
this.nSplitter = nSpiltter; NiwJ$Ah~X  
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} P-?ya!@"  

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public String getSSiteURL() j zaC  
{ ?=%Q$|]-  
return sSiteURL; /\S1p3EW*  
} Sn\S`D  
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public void setSSiteURL(String value) S0_#h)  
{ U`D.cEMfH  
sSiteURL = value; S?W!bkfn  
} %d5;JEgA:g  
,haCZH{  
f((pRP  
public String getSFilePath() @iZ"I i&+  
{ S+Aq0
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return sFilePath; /-ebx~FX&  
} %E95R8SL  
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public void setSFilePath(String value) Hnv{sND[  
{ }nDKSC/[V!  
sFilePath = value; e>-a\g  
} 6t0!a@t  
#Y3:~dmJ-  
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public String getSFileName() _`>F>aP  
{ q
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return sFileName; l[EnFbD6  
} 78v4cQ Y  
?=:wIMV  
=#N;ZG  
public void setSFileName(String value) lMu}|d  
{ 289@O-  
sFileName = value; jXEuK:exQ  
} sp4J%2b  
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public int getNSplitter() D-7PO3F:F  
{ *xEcX6ZHX  
return nSplitter; 93="sS  
} &UhI1mi]h  
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3siWq9.  
public void setNSplitter(int nCount) <$#b3F"I  
{ 3/P#2&jt  
nSplitter = nCount; huTa Ei  
} `I(#.*  
} j?&Rf,,%  
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/* Y6T1_XG  
**Utility.java Tu Q@b  
*/ #}
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package NetFox; v:*t5M >  
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public class Utility { 7\sJ=*  
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public Utility() ?Z-(SC  
{ x0^O?UR  
O$}p}%%y7  
]C|Zs=5  
} ]:CU.M1  
s#,~Zb=  
//线程睡眠 [
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public static void sleep(int nSecond) \Q+9sV 5,[  
{ 808E)  
try{ ,3_;JT"5  
Thread.sleep(nSecond); R:zPU   
} +NGjDa  
catch(Exception e) O>)<w Ms`  
{ B4
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e.printStackTrace (); x`@!hJc:[e  
} Lpw9hj|  
} D}|PBR  
bWzv7#dd=  
//日志 z=TaB^-)  
public static void log(String sMsg) tlw$/tMa  
{ ]>R|4K_  
System.err.println(sMsg); yT Pi/=G  
} 6X(Yv2X&4%  
1JIL6w_  
8X=cGYC#  
public static void log(int sMsg) TRwlUC3hQ  
{ B .p&,K  
System.err.println(sMsg); l6Hu(.Ls;j  
} 4`F(RweGx  
} >$=-0?.  
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;SAurG$  
/* uU v yZ  
**TestMethod.java )X{x\ /N  
*/ %u\Oj \8U  
package NetFox; *"V5j#F_  
I`"8}d@Jm  
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public class TestMethod { n}9vAvC  
;seD{y7!  
%4#,y(dO  
public TestMethod() rj[2XIO  
{ ///xx/weblogic60b2_win.exe 0z) 8i P  
try{ O)nLV~X  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); '< ]:su+  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); zx"'WM*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); O$jj&  
fileFetch.start(); /C(lQs*l  
} .'o<.\R8  
catch(Exception e){e.printStackTrace ();} &V5[Zj|]  
f}q4~NPn-  
"p>$^   
} NNZ%jJy?=,  
":E^&yQ  
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public static void main(String[] args) !g}?x3  
{ K;jV"R<9  
new TestMethod(); WF0%zxg]  
} CZB!vh0  
} Qs2E>C  
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