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http断点续传简单实现(java)

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/* 1sq1{|NW~  
**SiteFileFetch.java }" STc&1  
*/ y m?uj4I{  
package NetFox; drJUfsxV  
import java.io.*; AG|:mQO  
import java.net.*; /k KVIlO  
zh5ovA%  
LCqWL1  
public class SiteFileFetch extends Thread { S& F;~  
esd9N'.Q*  
e 3TKg  
SiteInfoBean siteInfoBean = null; //文件信息Bean $49;\pBZl  
long[] nStartPos; //开始位置 #Eqx E o;  
long[] nEndPos; //结束位置 6M[OEI5  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 s0'6r$xj  
long nFileLength; //文件长度 SP4(yJy&  
boolean bFirst = true; //是否第一次取文件 t\O#5mo  
boolean bStop = false; //停止标志 SmV}Wf  
File tmpFile; //文件下载的临时信息 'jYKfq~_cJ  
DataOutputStream output; //输出到文件的输出流 k/i&e~! \  
xu@+b~C\  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) .SDE6nvbW  
public SiteFileFetch(SiteInfoBean bean) throws IOException MC1&X'  
{ >gDKkeLD  
siteInfoBean = bean; j2oU1' b  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @&GY5<&b  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #e[igxwi  
if(tmpFile.exists ()) Jm 1n|f  
{ HMw}pp:  
bFirst = false; gR wRhA/  
read_nPos(); } a!HbH  
} cHJ4[x=  
else Y8/&1s_  
{ A~;+P  
nStartPos = new long[bean.getNSplitter()]; 2>)::9e4  
nEndPos = new long[bean.getNSplitter()]; Zbf~E {  
} |AS9^w  
/5~j"| U'  
i<!1s%i}  
>fp_$bjd  
} G4%dah 5  
}x:}9iphF  
~n%]u! 6  
public void run() Q 822 #  
{ h5lngw  
//获得文件长度 #KDN  
//分割文件 tdNAR|  
//实例FileSplitterFetch Vg7BK%  
//启动FileSplitterFetch线程 {*X|)nr  
//等待子线程返回 < fYcON  
try{ <W/YC 2b  
if(bFirst) #(-?i\i  
{ oTveY  
nFileLength = getFileSize(); 58]t iP"  
if(nFileLength == -1) 0+k=gO  
{ Mr@{3do$  
System.err.println("File Length is not known!"); c LfPSA  
} oot kf=  
else if(nFileLength == -2) 1$ENNq#0  
{  kZ=yb-~  
System.err.println("File is not access!"); K*5Ij]j&  
} #yOeL3|b'  
else /U="~{*-R  
{ \F<C$cys\  
for(int i=0;i<nStartPos.length;i++) Wv30;7~  
{ P%ZU+ET  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); =_[Ich,}  
} _ 3{8Zg  
for(int i=0;i<nEndPos.length-1;i++) r|3<UR%  
{ 3u'@anre  
nEndPos = nStartPos[i+1]; x";4)u=  
} BLb'7`t  
nEndPos[nEndPos.length-1] = nFileLength; 5yf`3vV|3@  
} b7HT<$Wg  
} uf`/-jY  
wpOM~!9R  
/p)y!5e  
//启动子线程 Hqb-)8 ~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; MX7$f (Hy  
for(int i=0;i<nStartPos.length;i++) VVc-Dx  
{ "Jg* /F  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d V3R)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), T5aeO^x  
nStartPos,nEndPos,i); )_K:A(V>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); X`7O%HiX/`  
fileSplitterFetch.start(); Hm_&``='  
} R".*dC,0'B  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3# idXc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); G$jw#a[L  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", oSH]TL2@Cd  
nEndPos = " + nFileLength); T8Ye+eP}  
// fileSplitterFetch[nPos.length-1].start(); q]v{o8:U  
o3.b='HAm  
87hU#nVYh  
//等待子线程结束 -_f-j  
//int count = 0; 2`V(w[zTr  
//是否结束while循环 G.qjw]Llf  
boolean breakWhile = false; J:\O .F#Fi  
aK8X,1g%)  
la{o<||Aq  
while(!bStop) lht :%Ts$  
{ Gk)6ljL  
write_nPos(); g?>   
Utility.sleep(500); Olr'n% }  
breakWhile = true; KXcE@q9  
!{XVaQ?x  
Cil1wFBb  
for(int i=0;i<nStartPos.length;i++) F#|mN0op  
{ xS_tB)C  
if(!fileSplitterFetch.bDownOver) ;eP. B/N  
{ nW]T-!  
breakWhile = false; ?d)FYB  
break; ]u%Y8kBe  
} wfM|3GS+.  
} ^Fwdi#g  
if(breakWhile) 8%;]]{(B  
break; D`PA@t  
K# h7{RE  
RYM[{]4b5F  
//count++; #$JY &!M  
//if(count>4) <KZ J  
// siteStop(); t#7owY$^  
} ~ \ Udl  
`%=!_|  
];Y tw6A  
System.err.println("文件下载结束!"); 0~ cbB  
} HCaEETk5  
catch(Exception e){e.printStackTrace ();} sDXQ{*6a  
} D#11 N^-K  
B{NGrC`5)  
nk+9 J#Gs  
//获得文件长度 ZV`o: Gd  
public long getFileSize() Sp@{5  
{ e it%U  
int nFileLength = -1; /?:q9Wy  
try{ sB<y(}u  
URL url = new URL(siteInfoBean.getSSiteURL()); YF13&E2`\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); CjU?3Ag  
httpConnection.setRequestProperty("User-Agent","NetFox"); oTf^-29d  
6"V86b0)h}  
z_87 ;y;=  
int responseCode=httpConnection.getResponseCode(); Uy$?B"Z  
if(responseCode>=400) 0lpUn74F  
{ s5oU  
processErrorCode(responseCode); S[RVk=A1  
return -2; //-2 represent access is error 8&v%>wxR@  
} {Pe+d3Eoo  
bYy7Ul6]  
p;LF-R  
String sHeader; b IZi3GmRF  
2%@<A  
k#<Y2FJa  
for(int i=1;;i++) CK1gzIg>  
{ /Xw wB  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); jn>RE   
//Utility.log(in.readLine()); 0zXF{5Up  
sHeader=httpConnection.getHeaderFieldKey(i);  t/a  
if(sHeader!=null) t<znz6  
{ }E\u2]  
if(sHeader.equals("Content-Length")) u]Dds;~"b  
{ B@,#,-=  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ;h7O_|<%  
break; E^t}p[s  
} !{ /AJb  
} G4)X~.Fy  
else \yY2 mr  
break; O+o_{t\R  
} ~Q5 i0s%  
} \>  
catch(IOException e){e.printStackTrace ();} /@]@Tz@'  
catch(Exception e){e.printStackTrace ();} P6;Cohfh  
p}h9>R  
{_]<mwd  
Utility.log(nFileLength); YMn_9s7<  
Yx<wYzD  
m/NXifi8l  
return nFileLength; 1)ZdkTF@H  
} jLreN#:9  
PA>su)N$  
/` 4B-Y4M4  
//保存下载信息(文件指针位置) k_7agW  
private void write_nPos() oCuKmK8  
{ G1/  
try{ <84d Vg  
output = new DataOutputStream(new FileOutputStream(tmpFile)); }G 1hB#j  
output.writeInt(nStartPos.length); 9d&}CZr  
for(int i=0;i<nStartPos.length;i++) j'|`:^ Sy  
{ `Qo}4nuRs  
// output.writeLong(nPos); 4AuJ1Z  
output.writeLong(fileSplitterFetch.nStartPos); C9E@$4*  
output.writeLong(fileSplitterFetch.nEndPos); Ozs&YZ  
} t}-rN5GO  
output.close(); R?+:Js/  
} G:{\-R'  
catch(IOException e){e.printStackTrace ();} r#/Bz5Jb*  
catch(Exception e){e.printStackTrace ();} \FjY;rqfKe  
} ;.b^A  
zNJ-JIo%  
rqYx\i?  
//读取保存的下载信息(文件指针位置) y`-5/4  
private void read_nPos() CFiO+p&  
{ F[==vte|  
try{ RTvzS]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); q<w Q/m  
int nCount = input.readInt(); 1<3!   
nStartPos = new long[nCount]; = j S  
nEndPos = new long[nCount]; wM&WR2  
for(int i=0;i<nStartPos.length;i++) ?K^~(D8(  
{ #BX^"J{~  
nStartPos = input.readLong(); $nW^Gqwj]1  
nEndPos = input.readLong(); pN7 v7rs  
} cY[qX/0~  
input.close(); ~[4zm$R^  
}  g=x1}nm  
catch(IOException e){e.printStackTrace ();} [;hCwj#  
catch(Exception e){e.printStackTrace ();} =E' .T0v  
} BH`GUIk  
V2_I=]p_  
>X-*Hu'U#  
private void processErrorCode(int nErrorCode) ,{u'7p  
{ A0 1 D-)  
System.err.println("Error Code : " + nErrorCode); wv_<be[?*  
} $+@xwuY'+  
UJ6zgsD1b?  
9>HCt*|_8  
//停止文件下载 nW `EBs  
public void siteStop() TGu]6NzyZ  
{ txXt<]N  
bStop = true; 9EKc{1 z  
for(int i=0;i<nStartPos.length;i++) 6`;+|H<$  
fileSplitterFetch.splitterStop(); `d. 4 L.],  
:_"%o=  
|!H@{o  
} }?XNA.Wz  
} keL!;q|r-)  
//负责部分文件的抓取 ?tFsSU  
**FileSplitterFetch.java I 6Mr[#*  
*/ UIi`bbJ  
package NetFox; mL[Y{t#N  
* IBCThj  
u3@v  
import java.io.*; e&J_uG  
import java.net.*; _f@, >l  
6b9 &V`  
:T #"bY  
public class FileSplitterFetch extends Thread { ;#Pc^Yzc1  
$yg=tWk  
61{IXx_  
String sURL; //File URL om}jQJ]KH  
long nStartPos; //File Snippet Start Position \cRe,(?O  
long nEndPos; //File Snippet End Position gTjhD(  
int nThreadID; //Thread's ID 3WQ"3^G  
boolean bDownOver = false; //Downing is over 2rJeON  
boolean bStop = false; //Stop identical ,7nA:0P  
FileAccessI fileAccessI = null; //File Access interface Vm <9/UG<  
uw`fC%-xh  
Jdp@3mP  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException o:"^@3  
{ UAq%Y8KA  
this.sURL = sURL; }g|)+V\A  
this.nStartPos = nStart; H.8Vm[W  
this.nEndPos = nEnd; 58H%#3Fy  
nThreadID = id; hpOUz%  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7JHS8C<]  
} Kk_h&by?  
('VHL!  
' 5%`[&  
public void run() &i%1\ o  
{ ccu13Kr>E  
while(nStartPos < nEndPos && !bStop) +1 j+%&).  
{ njN]0l{p  
/l@h[}g+d-  
2>!? EIE7  
try{ U?d4 ^  
URL url = new URL(sURL); Y94/tjt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -*r]9f6 x  
httpConnection.setRequestProperty("User-Agent","NetFox"); .a *^6TC.  
String sProperty = "bytes="+nStartPos+"-"; s55t>t,g6  
httpConnection.setRequestProperty("RANGE",sProperty); @"E{gM@B  
Utility.log(sProperty); >hbT'Or@  
^HasT4M+x  
Ee?+IZ H7|  
InputStream input = httpConnection.getInputStream(); Lb} cjI:  
//logResponseHead(httpConnection); 4]/i0\Vbam  
)mbRG9P  
XU19+mW=P  
byte[] b = new byte[1024]; :u$+lq  
int nRead; XTOZ]H*^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )Mj $/  
{ ';0NWFP  
nStartPos += fileAccessI.write(b,0,nRead); J \V.J/  
//if(nThreadID == 1) GxR, 3  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {BlKVsQ  
} U\\nSU  
,@'M'S  
+\O[)\  
Utility.log("Thread " + nThreadID + " is over!"); Udh!%QP%[w  
bDownOver = true; 6Y[|xu:N8Y  
//nPos = fileAccessI.write (b,0,nRead); WDdp(<  
} k;9"L90  
catch(Exception e){e.printStackTrace ();} ']]&<B}mz  
} U.B=%S  
} &RP}w%I1  
\1p5$0z  
f YuM`O  
//打印回应的头信息 {UR&Y  
public void logResponseHead(HttpURLConnection con) j2/3NF5&  
{ sUP !'Av  
for(int i=1;;i++) @~l?hf  
{ P_w\d/3  
String header=con.getHeaderFieldKey(i); * (4TasQu  
if(header!=null) o-D,K dY  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9IRvbE~2  
Utility.log(header+" : "+con.getHeaderField(header)); _\tGmME37  
else GK/Q]}Q8pZ  
break; U8 b1 sz  
} J '^xDIZX  
} *KXg;777  
8uO@S*)0  
M:~/e8Xv  
public void splitterStop() /<s $Am  
{ f @cs<x  
bStop = true; #!FLX*,  
} Bw[jrK  
426)H_wx  
8zRb)B+  
} %ycCNS  
:~2An-V  
kH43 T  
/* [?$|   
**FileAccess.java Gkr^uXNg#  
*//文件访问(定位,写) ?"aj&,q+  
package NetFox; iZy`5  
import java.io.*; L8~nx}UP5  
2z\4?HJy  
ecH-JPm'  
public class FileAccessI implements Serializable{ ClHaR  
H<SL=mb;  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 p ]zYj >e  
RandomAccessFile oSavedFile; 47iwb  
long nPos; #dLp<l)  
x\Y%/C[Kc  
3PonF4  
public FileAccessI() throws IOException $J |oVVct  
{ D k'EKT-  
this("",0); a* pZcv<  
} %acy%Sy  
B=;pyhc  
=oF6|\]{ ;  
public FileAccessI(String sName,long nPos) throws IOException ZHs hg`I`  
{ Te8BFcJG  
oSavedFile = new RandomAccessFile(sName,"rw"); id-VoHd K  
this.nPos = nPos; Hr$oT=x[  
oSavedFile.seek(nPos); MGO.dRy_  
} c#G]3vTdE  
s'^zudx  
;!@\|E  
public synchronized int write(byte[] b,int nStart,int nLen) }eX_p6bBw  
{ P#H#@:/3  
int n = -1; @Y>3-,o,S  
try{ wE75HE`gW  
oSavedFile.write(b,nStart,nLen); RZfC ?  
n = nLen; _^RN C)ol  
} z#!xqIg0  
catch(IOException e) K)qbd~<\  
{ sQ^>.yG  
e.printStackTrace (); Y\ T*8\h_[  
} 'D-#,X C  
&F}1\6{fL  
&bJ98 Nxl  
return n; =3=KoH/'  
} zJMKgw,i*  
l\^q7cXG  
LeW.uh3.  
} qD\%8l.]Z  
lq@Vb{Z  
AEwb'  
/* 4(4JQ(5  
**SiteInfoBean.java 8mA6l0  
*/ F$ .j|C1a  
package NetFox; $U jSP  
2LYd # !i  
ZZC= 7FB  
public class SiteInfoBean { dW7dMx  
1A- 8,)  
Hcd>\0  
private String sSiteURL; //Site's URL i&,U);T  
private String sFilePath; //Saved File's Path ~,e!t.339  
private String sFileName; //Saved File's Name t%z7#}9$  
private int nSplitter; //Count of Splited Downloading File IQ{Xj3;?y  
V8&/O)}o  
L1QQU  
public SiteInfoBean() bT-G<h*M  
{//nSplitter的缺省值为5 (?\ZN+V)  
//default value of nSplitter is 5 gE=~.P[ZX  
this("","","",5); fnnwe2aso  
} vP}K(' (  
oQ;f`JC^  
F.8{ H9`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 29ft!R>[  
{ YY!(/<VI  
sSiteURL= sURL; \ b9,>  
sFilePath = sPath; na']{a 1K  
sFileName = sName; ;(0:6P8I  
this.nSplitter = nSpiltter; `A <yDy  
! T,7  
TjI NxP-O  
} e+R.0E  
xdo{4XY^*W  
^y6Pkb P  
public String getSSiteURL() MF\n@lX  
{ jX&&@zMq  
return sSiteURL; \wRr6-!_  
} \>=YxB q  
J#V `W&\,6  
w78Ius,  
public void setSSiteURL(String value) lIjHd#q-C  
{ Aq'%a)Y2  
sSiteURL = value; b$R>GQ?#  
} , D1[}Lr=K  
JNp`@`0V  
1yB;"q&Xd  
public String getSFilePath() .;KupQ;*  
{ M<$l&%<`G  
return sFilePath; ` `;$Kr  
} ') 1sw%[2  
peqFa._W  
H9)uni   
public void setSFilePath(String value) ''v1Pv-  
{ Xi{(1o4%  
sFilePath = value; 8&C(0H]1  
} Jj6kZK  
hYd8}BvA  
|16 :Zoq  
public String getSFileName() VvF&E>f C  
{ X3m?zQbhv  
return sFileName; *Ra")(RnDK  
} n&C9f9S  
zRJy3/>  
k(qQvn  
public void setSFileName(String value) Wq9s[)F"Z  
{ ?^ErrlI_  
sFileName = value; Ro1' L1:  
}  ^,KR0  
Fo G<$9  
5nj~RUK  
public int getNSplitter() b<( W}$x  
{ &vF"I'V  
return nSplitter; )(L&+DDy  
} <@vE 3v;  
Fp]8f&l8  
-.*\J|S@g  
public void setNSplitter(int nCount) M<p)@p  
{ ppnj.tLz;r  
nSplitter = nCount; p 5o;Rvr  
} KFs` u6  
} }[DAk~  
R]Yhuo9,&n  
Azle ;\l`  
/* }1W$9\%  
**Utility.java y*(YZzF  
*/ >@L HJ61C  
package NetFox; a2 rv4d=  
=0)^![y]v  
m5p~>]}fYF  
public class Utility { "/'= gE  
L,D>E  
/r%+hS  
public Utility() $F-XXBp  
{ PW`Tuj  
jFXU xf  
&rd(q'Vi  
} I>5@s;  
\Cs<'(=  
//线程睡眠 S }n;..{  
public static void sleep(int nSecond) J9 =gv0  
{ bvx:R ~E$  
try{ %pp+V1FH  
Thread.sleep(nSecond); ~?&ijhZ  
} G'py)C5;  
catch(Exception e) f lB,_  
{ \+u qP:Ty  
e.printStackTrace (); biG9?  
} 84[^#ke  
} r9Z/y*q  
qc6IH9i`  
//日志 O$H150,Q  
public static void log(String sMsg) YzZF^q^I  
{ .HBvs=i  
System.err.println(sMsg); (6BCFl:/Q<  
} m#nxw  
cBI )?  
%8L<KJd  
public static void log(int sMsg) ]p!J]YV ]0  
{ i4I0oRp  
System.err.println(sMsg); MP,*W}@  
} 2jW>uk4/i  
} {Pb^Lf >  
3I5WDuq  
QRlzGRueR&  
/* Ng"vBycy  
**TestMethod.java Z~(XyaN  
*/ RNdnlD#P  
package NetFox; y2R=%EFh6  
re!8nuBsA  
]CZLaID~  
public class TestMethod { PBL^xlg  
+_eb*Z`5o  
pNlisS  
public TestMethod() ^JtHTLHL=  
{ ///xx/weblogic60b2_win.exe 5 DB>zou   
try{ WO-WoPO  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); i'wF>EBz  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); V@S/!h+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !7)ID7d  
fileFetch.start(); #'x?) AS  
} 5Mr;6 ]I<  
catch(Exception e){e.printStackTrace ();} {_Qxe1^g  
/ D ]B  
2]9<%-=S  
} U_- K6:tr  
kkBU<L2  
IBkH+j  
public static void main(String[] args) HzV+g/8>A  
{ y.:-  
new TestMethod(); $-]setdY  
} ^,K.)s  
} 8uxFXQ  
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