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http断点续传简单实现(java)

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/* gy#G;9p  
**SiteFileFetch.java |uRYejj#j  
*/ 6$csFW3R  
package NetFox; X&@>M}  
import java.io.*; b=L|GV@$  
import java.net.*; n^|7ycB'  
uhwCC  
[Z1,~(3  
public class SiteFileFetch extends Thread { fq):'E)  
bQu@.'O!k  
bZ+H u~  
SiteInfoBean siteInfoBean = null; //文件信息Bean >{0,dGm  
long[] nStartPos; //开始位置 N~(?g7  
long[] nEndPos; //结束位置 8lCo\T5"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 vv`53 Pbw)  
long nFileLength; //文件长度 ;jlI>;C;V  
boolean bFirst = true; //是否第一次取文件 2e({%P@2?  
boolean bStop = false; //停止标志 aLQ]2m  
File tmpFile; //文件下载的临时信息 !Pd)  
DataOutputStream output; //输出到文件的输出流 u 1Wixjd|  
H~0B5Hl!F  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) =RlAOgJ  
public SiteFileFetch(SiteInfoBean bean) throws IOException gA2]kZg  
{ )Oj{x0{\Q  
siteInfoBean = bean; SK,UW6h  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,twm)%caU  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); G49`a*Jn  
if(tmpFile.exists ()) !4$o*{9Lx:  
{ e\*N Lj_(  
bFirst = false; S3c%</'  
read_nPos(); /AUX7 m.8  
} ? 8S~R  
else VlxHZ  
{ edlsS}8^  
nStartPos = new long[bean.getNSplitter()]; UGA` `;f  
nEndPos = new long[bean.getNSplitter()]; v.Q+4 k  
} 3nUC,T%  
N'%l/  
$n::w c  
&>}f\ch/  
} y"w`yl{_  
9 tCF m.m  
b X/%Q^Y  
public void run() -}H EV#ev  
{ =~k#<q1^  
//获得文件长度 TO] cZZ<  
//分割文件 ;\Pq  
//实例FileSplitterFetch dp'k$el  
//启动FileSplitterFetch线程 xK_0@6  
//等待子线程返回  .V l  
try{ TF@k{_f  
if(bFirst) _Oc\hW  
{ j$z!kd+%  
nFileLength = getFileSize(); (Lkcx06e  
if(nFileLength == -1) mnq1WU;<  
{ X@:@1+U  
System.err.println("File Length is not known!"); x J\>;$CY  
} 1X#gHstD  
else if(nFileLength == -2) N[xa=  
{ NHaqT@:  
System.err.println("File is not access!"); 2>kk6=<5'  
} T2 XLP  
else .;;:t0PB  
{ s{0c.M  
for(int i=0;i<nStartPos.length;i++) XILreATK@  
{ |'Ksy{lA  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); nh/%0=S  
} _%PEv{H0.  
for(int i=0;i<nEndPos.length-1;i++) "!PN+gB  
{ QG;V\2T2[  
nEndPos = nStartPos[i+1]; aByd,uSe)_  
} R!RgQwEak  
nEndPos[nEndPos.length-1] = nFileLength; 7JLjA\k  
} |6Qn/N$+f  
} " VSma  
JP6+h>ft  
e/<'HM T  
//启动子线程 CVGQ<,KVW  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; -Dr)+Y  
for(int i=0;i<nStartPos.length;i++) aq.Lnbi/X  
{ g6;a2  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2U'Vq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), u 9kh@0  
nStartPos,nEndPos,i); JS(%:  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); DG 6W ^  
fileSplitterFetch.start(); HP[M"u  
} $`|\aXd[C*  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >8w=Vlp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); GFYHt!&[\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", UiN6-{v<2  
nEndPos = " + nFileLength); sN@=Ri?\  
// fileSplitterFetch[nPos.length-1].start(); ko`KAU<T_  
SfGl*2  
R9^R G-x  
//等待子线程结束 `:fh$V5J>  
//int count = 0; N=TDywRI  
//是否结束while循环 `SG8w_  
boolean breakWhile = false; QfI@=Kbg%#  
HD8*>p.  
Rj])c^ZA'*  
while(!bStop) b("M8}o  
{ je5GZFQw  
write_nPos(); 2NZC,znQ  
Utility.sleep(500); jmn<gJ2Of  
breakWhile = true; #;s5=aH  
pLsWy&G  
pXoT@[}  
for(int i=0;i<nStartPos.length;i++) n_P2l<F~/x  
{ h0zv @,u  
if(!fileSplitterFetch.bDownOver) &&`-A6`p  
{ unAu8k^  
breakWhile = false; /fC8jdp&  
break; i-`J+8|d  
} v|;}}ol  
} g I@I.=y  
if(breakWhile) 1\%2@NR  
break; Kb*X2#;*  
A%% Vyz  
eBg:[4 4V  
//count++; 71OQ?fc  
//if(count>4) XjU/7Q  
// siteStop(); 0yBiio  
} }"6 PM)s  
U6LENY+Ja  
oaM 3#QJ  
System.err.println("文件下载结束!"); Yjh02wo  
} =4:]V\o):'  
catch(Exception e){e.printStackTrace ();} )o_Pnq9_  
} 9{XV=a v  
uN9J?j*ir  
TX$4x~:  
//获得文件长度 3s$vaV~(a  
public long getFileSize() 9<-7AN}Z  
{ L3'$"L.|u  
int nFileLength = -1; Xx e07J~  
try{ i6$q1*  
URL url = new URL(siteInfoBean.getSSiteURL()); 6~!l7HqO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +$\/HO  
httpConnection.setRequestProperty("User-Agent","NetFox"); noQS bI @  
4ZrRgx2MD  
h0;R*c  
int responseCode=httpConnection.getResponseCode(); Hm 17El68  
if(responseCode>=400) 0{ !+N6MiR  
{ @XN|R  
processErrorCode(responseCode); M|}V6F_y  
return -2; //-2 represent access is error L<[%tvV  
} y5`$Aa4~  
zL/r V<  
(Kb_/  
String sHeader; ECr}7R%  
xpB* > zb  
HAdDr!/`  
for(int i=1;;i++) V~"-\@  
{ ID8u&:  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); U\x $@J  
//Utility.log(in.readLine()); 6QG"~>v7'(  
sHeader=httpConnection.getHeaderFieldKey(i); WADAp\&  
if(sHeader!=null) ){$*<#&H  
{ S$ Z?T  
if(sHeader.equals("Content-Length")) S)=3%toS>  
{ VrnZrQj<  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Ktn:6=,  
break; #-8%g{  
} '0 J*9  
} "-:-!1;Ji  
else fO t?2Bh  
break; Ln"D .gpq  
} vMeB2r<  
} ms`U,  
catch(IOException e){e.printStackTrace ();} BL1d= %2 R  
catch(Exception e){e.printStackTrace ();} rIQ%X`Y  
D/bF  
,qT+Vqpr{  
Utility.log(nFileLength); f yhBfA:u  
K2!GpGZu  
qw6i|JM%  
return nFileLength; 't3&,:Y  
} [K""6D  
pI1IDu*_Z  
s |!lw  
//保存下载信息(文件指针位置) 1Ms_2  
private void write_nPos() 8M8Odz\3 q  
{ *IWWD\U  
try{ 1w'W)x  
output = new DataOutputStream(new FileOutputStream(tmpFile)); FqXE6^  
output.writeInt(nStartPos.length); W=\45BJ  
for(int i=0;i<nStartPos.length;i++) +D d !  
{ A&D<}y/%  
// output.writeLong(nPos); C zb: nyRj  
output.writeLong(fileSplitterFetch.nStartPos); sMgRpem;  
output.writeLong(fileSplitterFetch.nEndPos); BD?u|Fd,i:  
} {wvBs87  
output.close(); vC!B}~RG  
} `CY c>n"  
catch(IOException e){e.printStackTrace ();} ~' w]%rh!  
catch(Exception e){e.printStackTrace ();} fxknfgbg  
} UT_kw}1o  
=buarxk  
#MUY!  
//读取保存的下载信息(文件指针位置) #T++5G  
private void read_nPos() K8RV=3MBLD  
{ l- $5CO  
try{ =B0AG9Fz  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); U88gJ[$  
int nCount = input.readInt(); 3@wio[  
nStartPos = new long[nCount]; l4*vM  
nEndPos = new long[nCount]; *=X61`0  
for(int i=0;i<nStartPos.length;i++) 1'f&  
{ !p!^[/9"c  
nStartPos = input.readLong(); rUh2[z8:  
nEndPos = input.readLong(); @K\ hgaQ  
} W<>R;~)  
input.close(); W0XfU`  
} QzS=oiL  
catch(IOException e){e.printStackTrace ();} mjKu\7F  
catch(Exception e){e.printStackTrace ();} @]7s`?  
} $g_|U:,  
m\G45%m  
*R3^:Y&  
private void processErrorCode(int nErrorCode) 1|:'jK#gE  
{ /<1zzeHRSD  
System.err.println("Error Code : " + nErrorCode); ca<OG;R^  
} DdqE6qE  
lP *p7Y '  
Og7^7))  
//停止文件下载 $},_O8R  
public void siteStop() N"s"^}M\  
{ Jw0I$W/  
bStop = true; Zmm6&OZ%  
for(int i=0;i<nStartPos.length;i++) eI98J"h%?  
fileSplitterFetch.splitterStop(); @*BVS'\  
IO7cRg'-F  
lC@wCgc  
} `*3;sq%`  
} OV|n/~  
//负责部分文件的抓取 s*R UYx  
**FileSplitterFetch.java XbIxGL  
*/ U#:N/ts*(  
package NetFox; X 4\V4_  
>dXB)yl  
(L`IL e*  
import java.io.*; UJ><B"  
import java.net.*; o:`^1  
`=%G&_3_<  
8ib e#jlg  
public class FileSplitterFetch extends Thread { |? rO  
g%okYH?  
>Se-5QtLcf  
String sURL; //File URL |E &|6h1  
long nStartPos; //File Snippet Start Position v%7Gh -P  
long nEndPos; //File Snippet End Position ? (M$r\\  
int nThreadID; //Thread's ID gfiFRwC`v  
boolean bDownOver = false; //Downing is over `jec|i@oO  
boolean bStop = false; //Stop identical u)vS,dzu  
FileAccessI fileAccessI = null; //File Access interface IZuP{7p$  
<Ok7 -:OxA  
}U?:al/m  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException o1thGttVDg  
{ *onVG5<  
this.sURL = sURL; ; W$.>*O  
this.nStartPos = nStart; 9Zr6 KA{  
this.nEndPos = nEnd; ;H9 W:_ahE  
nThreadID = id; |Xmzq X%  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 >0?ph<h1[q  
} qv[w 1;U"  
GJ:oUi  
[8>#b_>  
public void run() J;ycAF~  
{ r`i.h ^2De  
while(nStartPos < nEndPos && !bStop) 5 %+epzy  
{ =.l>Uw!  
mR~S$6cc  
JFq<sY!  
try{ >7z(?nQYT^  
URL url = new URL(sURL); n[\L6}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9'p*7o  
httpConnection.setRequestProperty("User-Agent","NetFox"); S<z8  
String sProperty = "bytes="+nStartPos+"-"; h6?o)Q>N  
httpConnection.setRequestProperty("RANGE",sProperty); ),H1z`c&I  
Utility.log(sProperty); E:;MI{;7  
~MP/[,j`  
EqOhzII^  
InputStream input = httpConnection.getInputStream(); loUZD=Ph  
//logResponseHead(httpConnection); *VaQ\]:d  
+_jM$?:F}  
3Xy~ap>Y  
byte[] b = new byte[1024]; r@PVSH/  
int nRead; ?;A\>sP  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) GK1P7Qy?V  
{ =i6k[rg  
nStartPos += fileAccessI.write(b,0,nRead); OS1f}<  
//if(nThreadID == 1) _-2;!L#/  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j+e s  
} NTSIClm}U  
qcge#S>  
>8&fFq  
Utility.log("Thread " + nThreadID + " is over!"); N*\r i0  
bDownOver = true; l;@bs  
//nPos = fileAccessI.write (b,0,nRead); kx;7/fH  
} Q_dMuoI  
catch(Exception e){e.printStackTrace ();} k%iwt]i%  
} "whs?^/  
} fcy4?SQ.<i  
/N,\st  
x6ayFq=  
//打印回应的头信息 5Q:%f  
public void logResponseHead(HttpURLConnection con) &da:{  
{ 'j!n   
for(int i=1;;i++) ]W5p\(1g  
{ qpzyl~g:C  
String header=con.getHeaderFieldKey(i); M!X^2  
if(header!=null) (EH}lh }%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); @z:E]O}  
Utility.log(header+" : "+con.getHeaderField(header)); L uW""P/  
else OzR<jCOS  
break; 2`A[<S  
} RL H!f1cta  
} W$W w/mcl+  
Fl*<N  
7 0EH~  
public void splitterStop() wOLV?Vk  
{ "U$](k.<VA  
bStop = true; `fl$ o6S/  
} 3Bcv"O,B!{  
X$?0C{@.}  
d(9-T@J  
} i 1Kq (7  
\GKR(~f  
1H-~+lf  
/* 4J?\JcGs  
**FileAccess.java /2MZH  
*//文件访问(定位,写) 8~T=p:z'  
package NetFox; tY:,9eh7B  
import java.io.*; _xBhMu2f  
K /%5\h  
~Q5]?ZNX  
public class FileAccessI implements Serializable{ 5Zmc3&vRl  
TI\EkKu"  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \rE] V,,2  
RandomAccessFile oSavedFile; D(WV k  
long nPos; 3{$>-d  
NiQ Y3Nj  
[ $"  
public FileAccessI() throws IOException D *IeG>%  
{ +;=>&XR0m  
this("",0); keStK8  
} f1?%p)C  
wA6E7vi'  
-B(p8YH  
public FileAccessI(String sName,long nPos) throws IOException 1QnaZhu'  
{ ):A.A,skf  
oSavedFile = new RandomAccessFile(sName,"rw"); 7xR:\FBa^  
this.nPos = nPos; ` k(Q:  
oSavedFile.seek(nPos); nc1?c1s,f  
} T0.sL9  
e E(+  
0QxBC7` qp  
public synchronized int write(byte[] b,int nStart,int nLen) =@q,/FR-  
{ UMT}2d%  
int n = -1; B\l0kiNT  
try{ zMM ~4?4  
oSavedFile.write(b,nStart,nLen); "KSdC8MS  
n = nLen; U??OiKVZ+  
} `:jF%3ks+0  
catch(IOException e) e)}=T0 s  
{ LabI5+g  
e.printStackTrace (); k ~F ,n  
} e2 g`T{6M  
[xQ.qZ[h&  
9[lk=1.qN  
return n; ^NM>x Ienf  
} F+j"bhe  
B~J63Os/  
@;KvUR/+FE  
} Dz/MIx  
BB ::zBg  
ZwiXeD+4  
/* <*P)"G  
**SiteInfoBean.java .ud&$-[a  
*/ xsNOjHk  
package NetFox; mS49l  
!D V0u)k(  
N P5K1:  
public class SiteInfoBean { .q!i +0  
?FEh9l)d\  
oq b(w+<  
private String sSiteURL; //Site's URL B}K<L\S  
private String sFilePath; //Saved File's Path J,s:CBCGL  
private String sFileName; //Saved File's Name FMzG6nrdBN  
private int nSplitter; //Count of Splited Downloading File J aJ/ |N  
e AaS }g 0  
~-uDN)  
public SiteInfoBean() '(ZT }N  
{//nSplitter的缺省值为5 OYb:);o,iE  
//default value of nSplitter is 5 |`fuu2W!  
this("","","",5); ^t$uDQ[hA  
} ;Cjj_9e,:  
dxH.  
y(E<MRd8V  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) MmFtG-  
{ #&?}h)Jr'  
sSiteURL= sURL; 4r86@^c*  
sFilePath = sPath; _'^_9u G  
sFileName = sName; 7Jz 9%iP  
this.nSplitter = nSpiltter; 2 gca *  
:"b:uQ  
Vn\jUEC  
} 2^nws  
][YuJUK8  
{M= *>P]E  
public String getSSiteURL() 7s;;2<k;_  
{ L|;sB=$'{  
return sSiteURL; ZF8`= D`:R  
} FPPl^  
rEbH< |  
.' h^  
public void setSSiteURL(String value) bQ&%6'ck  
{ pd.unEWwF  
sSiteURL = value; )h{+pK  
} x|()f 3{.  
Md8<IFi9]Q  
P8;1,?ou  
public String getSFilePath() A]drNFE  
{ +oHbAPs8  
return sFilePath; ou`KkY||  
} =)*Z rD  
$D D esy3  
/s+S\ djk  
public void setSFilePath(String value) -"^xg"  
{ rhly.f7N=A  
sFilePath = value; u g;~dhe~  
} ~&+a.@T  
eZ0-O /_i  
EB6X Yr  
public String getSFileName() 7@m+ y  
{ }OTJ{eG  
return sFileName; z2!4w +2  
} SUW=-M  
x3.,zfWs  
j *;.>akY7  
public void setSFileName(String value) \~t!M~H  
{ TmM~uc7mj  
sFileName = value; Q}a(vlZ  
} Z%=A[` 5]  
5w+&plIJ  
c~OvoTF,  
public int getNSplitter() @D `j   
{ H<P d&  
return nSplitter; hb %F"Q  
} @O-\s q  
]1W]  
"<%J^Z9G  
public void setNSplitter(int nCount) U6y`:G;.  
{ 1?.NJ<)F  
nSplitter = nCount; zE?dQD^OD  
} 9\=SG"e(  
} cqW(9A|8  
ZPz=\^  
(hIo0 .  
/* 9wO2`e )  
**Utility.java /Nob S'd  
*/ fL]jk1.Xv-  
package NetFox; s<aG  
|`V=hqe{  
 !$!%era`  
public class Utility { `R-?+76?  
U3UA  
'#.D`9YI<  
public Utility() tDfHO1pS  
{ "V`DhOG&  
-w5sXnS  
Iek ] /=  
} I:YgKs)[  
e#k)F.TZ:%  
//线程睡眠 >l=^3B,j  
public static void sleep(int nSecond) IY mkZ?cW  
{ HS\'{4P  
try{ A4b+:MQ*OX  
Thread.sleep(nSecond); Nw-U*y  
} dy'lM ;@-  
catch(Exception e) `>)pqI%L[g  
{ !;hp  
e.printStackTrace (); x~{W(;`!  
} N%1nii  
} UdA,.C0  
v$g\]QS p  
//日志 sBqOcy  
public static void log(String sMsg) VwK7\j V  
{ Ai5+ ;8z+  
System.err.println(sMsg); (NJ.\m  
} wwJs_f\  
j#Lj<jX!xR  
FP*kA_z$  
public static void log(int sMsg) FT-=^VA\  
{ LB}J7yEQvj  
System.err.println(sMsg); xe3Jxo !U  
} !T8sWMY  
} 1rLxF{,  
#YK3Ogb,  
d3#e7rQ8  
/* {SRD\&J[  
**TestMethod.java jR@>~t[}o  
*/ $d,{I8d  
package NetFox; s'IB{lJ9  
l m(mY$B*_  
>$=l;jO`n  
public class TestMethod { xh!T,|IR  
,Z! I^  
C',uY7}<  
public TestMethod() pr,1pqiAf  
{ ///xx/weblogic60b2_win.exe /;E=)(w  
try{ :_,3")-v  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :C,}DyZy  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -pQ?ybQ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); zG^$-L.n  
fileFetch.start(); 4%JJ} {Ff  
} UQ@szE  
catch(Exception e){e.printStackTrace ();} &0J8I Cd=  
pqju@FD *  
D>Rlm,U  
} '- #QK'p  
G-sQL'L[U  
7m?fv Ky  
public static void main(String[] args) jtE'T}!d  
{ R4$(NNC+/  
new TestMethod(); &yOl}?u  
} T\:*+W37  
} HYY+Fv5  
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