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http断点续传简单实现(java)

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/* q^6+!&"  
**SiteFileFetch.java +F dB '  
*/ lJ@][;  
package NetFox; *)+ut(x|#  
import java.io.*; Z@hD(MS(C  
import java.net.*; z=$jGL  
7FRmx 4(!  
y8fsveX  
public class SiteFileFetch extends Thread { ;5@  t[r  
>>[ G1   
vTv]U5%:>%  
SiteInfoBean siteInfoBean = null; //文件信息Bean Y!;|ld  
long[] nStartPos; //开始位置 |!y A@y?  
long[] nEndPos; //结束位置 4H@Wc^K  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 |HZTN"  
long nFileLength; //文件长度 pmX#E  
boolean bFirst = true; //是否第一次取文件 T?4G'84nN  
boolean bStop = false; //停止标志 8i?l02  
File tmpFile; //文件下载的临时信息 Qt|c1@J  
DataOutputStream output; //输出到文件的输出流 EUIIr4]  
`"%T=w  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) *OQG 4aWy  
public SiteFileFetch(SiteInfoBean bean) throws IOException 4lZ$;:Jg  
{ q%ow/!\;  
siteInfoBean = bean; eI@ q|"U  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,^S@EDq  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); *b]; |n{  
if(tmpFile.exists ()) iOG[>u0h  
{ dx ;k`r$w  
bFirst = false; +iI&c s  
read_nPos(); D-,L&R!`  
} fryJW=  
else E= `6-H{  
{ dg^L=  
nStartPos = new long[bean.getNSplitter()]; je]}R>[r5  
nEndPos = new long[bean.getNSplitter()]; \e`~i@) ~Z  
} w9|w2UK  
5+fLeC;  
s`#(   
Q[#vTB$f  
} 7w3CXY  
}2ZsHM^]%  
Oh4AsOj@  
public void run() `c'W-O/  
{ bO<CR  
//获得文件长度 hTwA%  
//分割文件 'g9"Qv?0{`  
//实例FileSplitterFetch ApjOj/  
//启动FileSplitterFetch线程 e)?Fi  
//等待子线程返回 R6=$u{D  
try{ b"TjGE  
if(bFirst) {aM<{_v  
{ Uo-`>7  
nFileLength = getFileSize(); pC_O:f>vJ  
if(nFileLength == -1) yS=oUE$  
{ t-LG }nv  
System.err.println("File Length is not known!"); u a\,->  
} _sbp6ZO_  
else if(nFileLength == -2) ;*,f<  
{ not YeY7wR  
System.err.println("File is not access!"); B*E2.\~  
} i<(Xr  
else mXXt'_"  
{ Bphof0{<}  
for(int i=0;i<nStartPos.length;i++) 2ZQ}7`Y  
{ C{d7J'Avk  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); sCu+Lg~f  
} aj}(E +  
for(int i=0;i<nEndPos.length-1;i++) Vrvic4  
{ 5[Pr|AY  
nEndPos = nStartPos[i+1]; l{D'uI[&  
} M2U&?V C!  
nEndPos[nEndPos.length-1] = nFileLength; rLX4jT^  
} YTw#J OO  
} j+HHQd7Y  
L;od6<.*m  
@&}q} D  
//启动子线程 Vi$-Bw$@  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; pBw0"ff  
for(int i=0;i<nStartPos.length;i++) 07hF2[i  
{ ~ Uo)0  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]Ta N{"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), K!KMQr`  
nStartPos,nEndPos,i); n!qV>k9Y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  H}:LQ~_2  
fileSplitterFetch.start(); 4WB-Ec  
} AdWq Q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $k$4% 7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6eokCc"o  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5K?}}Frrt`  
nEndPos = " + nFileLength); C2{lf^9:&  
// fileSplitterFetch[nPos.length-1].start(); D0N9Ksq  
\);4F=h}f  
Y{*u&^0{  
//等待子线程结束 r `eU~7  
//int count = 0; l (3bW1{n  
//是否结束while循环 P<K){V  
boolean breakWhile = false; B*gdgM*`  
O=9-Qv|  
r4,VTy2Qe  
while(!bStop) CpQN,-4  
{ $u/E\l  
write_nPos(); +NFzSal  
Utility.sleep(500); ci+tdMA  
breakWhile = true; <ioO,oS'  
S'HnBn /  
ko^\ HSXl  
for(int i=0;i<nStartPos.length;i++) 46k?b|Q  
{ XerbUkZ  
if(!fileSplitterFetch.bDownOver) 95<EN (oUD  
{ f}D1|\7  
breakWhile = false; F"N60>>  
break; N&[D>G]>v  
} |_ G )qp;  
} nW|wY.  
if(breakWhile) boo }u  
break; &* E+N[  
gqWupL  
7+hK~  
//count++; c=AOkX3UD  
//if(count>4) e]Zngt?b  
// siteStop(); al 20V  
} A?G^\I~v  
!yhh8p3  
&ZTr  
System.err.println("文件下载结束!"); 3R&lqxhg  
} _`#3f1F@[  
catch(Exception e){e.printStackTrace ();} &5 L<i3BX  
} cv/_ r#vN  
^V %rag  
Wpc|`e<  
//获得文件长度 rS1fK1dy s  
public long getFileSize() *Y@nVi  
{ RyRpl*^  
int nFileLength = -1; Pm$q]A~  
try{ t^ZV|s 1  
URL url = new URL(siteInfoBean.getSSiteURL()); }y%oT P&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [{r}u  
httpConnection.setRequestProperty("User-Agent","NetFox"); &gI~LP  
Ssk}e=]  
u=YX9Mo!  
int responseCode=httpConnection.getResponseCode(); Qeu\&%C!<  
if(responseCode>=400) ?h!i0Rsm  
{ }za[E>z  
processErrorCode(responseCode); '<0J@^vZ  
return -2; //-2 represent access is error I=;+n-  
} lHZU iB  
^GBe)~MT  
,j5&6X=1M  
String sHeader; l$hJE;n  
S1U@UC  
N4*G{g  
for(int i=1;;i++) a" H WGY  
{ ~8m=1)A{(  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); <94_@3  
//Utility.log(in.readLine()); (5Sivw*mP  
sHeader=httpConnection.getHeaderFieldKey(i); IG3,XW  
if(sHeader!=null) 6DZ),F,M  
{ Iyo@r%I  
if(sHeader.equals("Content-Length")) kPjd_8z2n  
{ ``A 0WN  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); r_YIpnJ  
break; 7#<c>~   
} 8?Z4-6!{V,  
} +w8R!jdA  
else y ?G_y  
break; E\u#t$  
} ?b!Fa  
} <|?K%FP7Z  
catch(IOException e){e.printStackTrace ();} Y4IGDY*  
catch(Exception e){e.printStackTrace ();} 5 |/9}^T  
Ez{MU@Fk  
ql<rU@  
Utility.log(nFileLength); L>Mpi$L  
C%~a`e|/Y  
N0>0z]4;q  
return nFileLength; VxFOYC>p  
} $F.kK%-*  
A^2L~g[^Q  
L^^4=ao0  
//保存下载信息(文件指针位置) B4XZko(  
private void write_nPos() gKg-O  
{ CB~Q%QLG  
try{ *MI*Rz?4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); S^Au#1e   
output.writeInt(nStartPos.length); H[b}kZW:a  
for(int i=0;i<nStartPos.length;i++) }qjCTEs}  
{ v_<2H' *Q  
// output.writeLong(nPos); iE.-FZc  
output.writeLong(fileSplitterFetch.nStartPos); )wVIb)`R>Y  
output.writeLong(fileSplitterFetch.nEndPos); :SV>+EDY   
} $0^P0RAH  
output.close(); {7Mj P+\  
} ^2 ]LV6I  
catch(IOException e){e.printStackTrace ();} ^h &I H|  
catch(Exception e){e.printStackTrace ();} 8^B;1`#  
} ~ 7)A"t  
an2AX% u  
*4|Hqa  
//读取保存的下载信息(文件指针位置) !6}O.Nu  
private void read_nPos() L_em')  
{ :D7|%KK  
try{ oR p:B &  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); TEsnNi 1  
int nCount = input.readInt(); ~L7:2weV[  
nStartPos = new long[nCount]; &:=$wc  
nEndPos = new long[nCount];  ,YhwpkL  
for(int i=0;i<nStartPos.length;i++) ,%YBG1E[y  
{ }`yiT<z  
nStartPos = input.readLong(); f f7(  
nEndPos = input.readLong(); c<#<k}y  
} \M]-bw`  
input.close(); ^Y{D^\} ,  
} ~Ki`Ze"x  
catch(IOException e){e.printStackTrace ();} H6aM&r9}  
catch(Exception e){e.printStackTrace ();} Q:6VYONN  
} ESb ]}c:  
tZ2e!<C  
[0[M'![8M  
private void processErrorCode(int nErrorCode) YDmWN#  
{ @ \2#Dpr  
System.err.println("Error Code : " + nErrorCode); #=}$OFg  
} &W }<:WH~  
^6p'YYj"5  
~2 u\  
//停止文件下载 buk=p-oi  
public void siteStop() l2hG$idC  
{ `:M^8SYrL  
bStop = true; "8V{5e!%j'  
for(int i=0;i<nStartPos.length;i++) V,%L ~dI  
fileSplitterFetch.splitterStop(); SK$Vk[c]  
}jSj+*  
x?D/.vrOY  
} bl/,*Wx:4.  
} T@^]i&  
//负责部分文件的抓取 l0tYG[  
**FileSplitterFetch.java z (c9,3  
*/ b]gY~cbI8  
package NetFox; 8Z85D  
=neL}Fav56  
GJ 'spgz  
import java.io.*; xn}BB}s{t  
import java.net.*; *@ED}Mj+  
GbU@BN+_  
!NKmx=I]  
public class FileSplitterFetch extends Thread { oN(-rWdhZ  
5, b]V)4  
;K:8#XuV  
String sURL; //File URL !PUp>(  
long nStartPos; //File Snippet Start Position [;O^[Iybf:  
long nEndPos; //File Snippet End Position A[UP"P~u/  
int nThreadID; //Thread's ID u@%|k c`  
boolean bDownOver = false; //Downing is over jJwkuh8R  
boolean bStop = false; //Stop identical Ul Mi.;/^  
FileAccessI fileAccessI = null; //File Access interface /48 =UK  
+?`b=6e(`  
:u%$0p>  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >CgO<\  
{ \|Dei);k  
this.sURL = sURL; 2H?d+6Pt3  
this.nStartPos = nStart; %c^ m\ E  
this.nEndPos = nEnd; wX1ig  
nThreadID = id; fMK#x\.4  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 l54|Q  
} FquFRx  
Sav`%0q?7a  
G@d`F  
public void run() . gZZCf&?  
{ oUW<4l  
while(nStartPos < nEndPos && !bStop) u}H$-$jE  
{ e9u@`ZC07  
dYOF2si~%  
3/M.0}e  
try{ F@YV]u>N  
URL url = new URL(sURL); |;;!8VO3J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); s ?l%L!  
httpConnection.setRequestProperty("User-Agent","NetFox"); zREJ#r  
String sProperty = "bytes="+nStartPos+"-"; B!aK  
httpConnection.setRequestProperty("RANGE",sProperty);  YRB%:D@u  
Utility.log(sProperty); Fm j=  
]@xL=%   
|Svk^mq  
InputStream input = httpConnection.getInputStream(); S-E++f9D~  
//logResponseHead(httpConnection); 6 o[/F3`  
2f:Mm'XdB  
0|)19LR  
byte[] b = new byte[1024]; oJaAM|7uv  
int nRead; |LYKc.xo  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |9NIGg'n  
{ 9Yw]Y5l  
nStartPos += fileAccessI.write(b,0,nRead); WO%h"'iJ  
//if(nThreadID == 1) r25Z`X Z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fU*C/ d3  
} ,9/5T:2  
Ex($  
9F_6}.O  
Utility.log("Thread " + nThreadID + " is over!"); +?N}Y{Y&  
bDownOver = true; fCEz-TMW  
//nPos = fileAccessI.write (b,0,nRead); kC^.4n om  
} StQ@g  
catch(Exception e){e.printStackTrace ();} rH}fLu8,;Q  
} C%H9[%k  
} kN'Thq/ZE  
v}il(w;O  
a[O6YgO  
//打印回应的头信息 cNP/<8dq  
public void logResponseHead(HttpURLConnection con) 0P 5BArJ?  
{ N <pbO#e  
for(int i=1;;i++) :Z2tig nL  
{ F ! )-|n}  
String header=con.getHeaderFieldKey(i); |6B6?'  
if(header!=null) }bfn_ G  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *)PG-$6X&  
Utility.log(header+" : "+con.getHeaderField(header)); `facFt[\  
else {fG|_+tl3o  
break; -Z?Ck!00  
} F RH&B5w  
} lYQtv=q  
R# 6H'TVE  
Y-&|VE2  
public void splitterStop() 2lz {_9  
{ NV!4(_~  
bStop = true; Hhf72IX  
} Wu{&;$  
=WRO\lgv.  
3hJH(ToO  
} U1^l+G^,~  
k&DGJ5m$.  
0(TvQ{  
/* y\_wWE  
**FileAccess.java 0!IPcZjY7  
*//文件访问(定位,写) +2O=s<fp  
package NetFox; MuSaK %  
import java.io.*; Es:6  
z_(eQP])  
V [4n'LcE  
public class FileAccessI implements Serializable{ @W [{2d  
i_YW;x  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 }vsO^4Sjc  
RandomAccessFile oSavedFile; )H+h ;U  
long nPos; s-5wbi.C  
RO(iHR3cA  
:1BM=_WwI  
public FileAccessI() throws IOException Zi3T~:0p:  
{ Sf5]=F-w  
this("",0); Hd*Fc=>"Y  
} 5byeWH0n3  
|B|@GF?:  
pU DO7Q]  
public FileAccessI(String sName,long nPos) throws IOException r9 ;`  
{ |J?:91  
oSavedFile = new RandomAccessFile(sName,"rw"); C*j9Iaj  
this.nPos = nPos; FAd``9kRT  
oSavedFile.seek(nPos); x)\V lR  
} '{^8_k\}B  
5\?3$<1 I  
g$gS7!u,  
public synchronized int write(byte[] b,int nStart,int nLen) q4k`)?k9  
{ k1wr/G'H[  
int n = -1; 9i[4"&K  
try{ fn?VNZ`J  
oSavedFile.write(b,nStart,nLen); Okoo(dfM  
n = nLen; |<2 *v-a  
} $/.<z(F  
catch(IOException e) zg7G^!PU  
{ NY 4C@@"  
e.printStackTrace (); zze z~bv7:  
} 8vO;IK]9b^  
-Qg,99M  
wzxdVn 'S  
return n; E4i@|jE~)  
} rV U:VL`2  
9C?cm:  
FRS28D  
} DOT=U _  
59K}  
CnQg*+  
/* W1<.OO\J  
**SiteInfoBean.java ?to1rFrU  
*/ W7W3DBKtSm  
package NetFox; 5R"2Wd  
+0U#.|?  
z[Z2H5[  
public class SiteInfoBean { hafECs  
4D GY6PS  
Y@ObwKcG  
private String sSiteURL; //Site's URL Kc-4W6?$  
private String sFilePath; //Saved File's Path v#Sj|47  
private String sFileName; //Saved File's Name 'Y ,1OK  
private int nSplitter; //Count of Splited Downloading File fIH#  
5<^'Cy  
\{:%v#ZZ  
public SiteInfoBean() 1ThwvF%Qo  
{//nSplitter的缺省值为5 >kZ6f4  
//default value of nSplitter is 5 g?gqkoI  
this("","","",5); +q l  
} Z/n3aYM  
[Ek42%  
)ib7K1GJ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) :TlAL# s&  
{ w)^\_uAlS  
sSiteURL= sURL; OZa88&  
sFilePath = sPath; ] ZDTn  
sFileName = sName; #>" }q3RO  
this.nSplitter = nSpiltter; 2Gm-\o&Td"  
fqN75['n  
@+$cZ3,  
} U @)k3^  
z'T=]- D  
keaj3#O  
public String getSSiteURL() NWb} OXK/  
{ p %L1uwLG  
return sSiteURL; .hc|t-7f  
} ?Q;kZmQl  
_/ct=  
pFEZDf}:  
public void setSSiteURL(String value) ' *}^@[&  
{ rAM *\=  
sSiteURL = value; ) b/n)%6  
} ENO? ;  
b~jIv:9T  
epn#qeX  
public String getSFilePath() !O 4<I_EY{  
{ >dyhox2*"  
return sFilePath; is9}ePC7Xu  
} 5GaoJ v  
oPCrD.s  
FOeVRq:#  
public void setSFilePath(String value) "Wo.8  
{ n>br,bQe  
sFilePath = value; xC[~Fyhp  
} 0r0c|*[+4z  
\QliHm!  
El'yiJ  
public String getSFileName() Q,D0kS P  
{ <{E;s)hD?  
return sFileName; J6eJIKK  
} w2 /* `YO  
g})6V  
U@#?T  
public void setSFileName(String value) u1tq2"D8  
{ P@2tR5<R  
sFileName = value; ,.[.SU#V  
} P`p6J8}4  
vc )9Re$  
{,i=>%X*  
public int getNSplitter() `b#/[3  
{ `'*F 1F  
return nSplitter; 2H[=l Y  
} D!X>O}  
*e%Dg{_  
M8\G>0Hc6  
public void setNSplitter(int nCount) I<c@uXXV;!  
{ kmmL>fCV"M  
nSplitter = nCount; "|F. 'qZrm  
} 3b+7^0frY#  
} PP!l  
,wEM Jh  
Tku /OG'  
/* /.7$`d  
**Utility.java ,c@r` x  
*/ cT_uJbP+  
package NetFox; TP~( r  
Hr /W6C  
1a5?)D  
public class Utility { U&,r4>V@h>  
6 M*b6  
r4 9UJE  
public Utility() ?6 8$3;  
{ wDB)&b  
|~z8<  
+xn&K"]:3  
} chKF6n  
Uy(vELB  
//线程睡眠 W"W@WG9X0  
public static void sleep(int nSecond) g4zT(,ZY  
{ {`+bW"9  
try{ A,3@j@bdy  
Thread.sleep(nSecond); =t@:F  
} h~,x7]w6  
catch(Exception e) Bh\ [ CY  
{ g!p+rq_f  
e.printStackTrace (); sVE>=0TVP  
} Z~duJsH  
} #x, ]D  
2ZU@>W  
//日志 ''$`;?t>  
public static void log(String sMsg) L v  
{ 'Y hA  
System.err.println(sMsg); $/4Wod*l  
} h |s*i  
R'vdk<  
3js)niT9u  
public static void log(int sMsg) E^oEG4 X@  
{ 3Qqnw{*  
System.err.println(sMsg); %2^['8t#NH  
} Bx\#`Y  
} }W- K  
d 8xk&za  
\7|s$ XQ\  
/* 7'-)/Pk  
**TestMethod.java Iu)L3_+  
*/ 9c"0~7v  
package NetFox; c80 }1  
z zulVj*  
EZ:I$X  
public class TestMethod { L@C >-F|p  
mJwv&E  
A>qd2  
public TestMethod() 1gF*Mf_7  
{ ///xx/weblogic60b2_win.exe ph Wc 8[Q  
try{ :GN)7|:  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~|X99?P  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); {Uik|  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Gh>"s#+  
fileFetch.start(); ;yRwoTc)Y  
} .a 'ETNY:>  
catch(Exception e){e.printStackTrace ();} _DNkdS [[  
|usnY  
XS}Zq4H  
} <ol$-1l#9  
/.pa ??u  
b|X>3(  
public static void main(String[] args) y}(_SU  
{ MuCQxzvkhf  
new TestMethod(); `77;MGg*  
} h#(.(d  
} :d!i[W*  
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