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http断点续传简单实现(java)

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/* aT>'.*\]  
**SiteFileFetch.java 'u4<BQVV[  
*/ }by;F9&B  
package NetFox; ^?7`;/  
import java.io.*; ;r_F[E2z  
import java.net.*; Dn&D!B  
8V^oP] Y  
=6"2UC&  
public class SiteFileFetch extends Thread { -gSUjP  
])xx<5Jt4  
P:30L'.=[  
SiteInfoBean siteInfoBean = null; //文件信息Bean h%}/Cmx[  
long[] nStartPos; //开始位置  A) ;  
long[] nEndPos; //结束位置 mEw ~yOW]M  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 R" ;x vo*  
long nFileLength; //文件长度 na9sm  
boolean bFirst = true; //是否第一次取文件 1 $/%m_t  
boolean bStop = false; //停止标志 }:X*7 n(&  
File tmpFile; //文件下载的临时信息 S S2FTb-m  
DataOutputStream output; //输出到文件的输出流 \jOA+FU [  
H,Z;=N_  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) rE}%KsZ  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1pArZzm>  
{ ZovW0Q)m  
siteInfoBean = bean; =c/wplv*  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }ZYv~E'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); gw, UQbnu  
if(tmpFile.exists ()) ma"3qGy  
{ ]IoUwgpI)  
bFirst = false; VeW>[08  
read_nPos(); *:ZDd  
} S H!  
else 6Yx4lWBR?  
{ .Fdgb4>BXX  
nStartPos = new long[bean.getNSplitter()]; :2 *g~6  
nEndPos = new long[bean.getNSplitter()]; 0q&<bV:D  
} F(tx)V ~T3  
-r-k_6QP  
^J$2?!~  
R8ZK]5{o  
} spt6]"Ni  
KXx32 b,~  
e" St_z(  
public void run() j'A_'g'^  
{ dBz/7&Q   
//获得文件长度 7=;R& mqC  
//分割文件 D9 g#F f6  
//实例FileSplitterFetch :]\([Q+a  
//启动FileSplitterFetch线程 eEuvl`&  
//等待子线程返回 <StN%2WQ1  
try{ .&DhN#EN0  
if(bFirst) +j< p \Kn>  
{ ,6-:VIHQ  
nFileLength = getFileSize(); Wk)OkIFR  
if(nFileLength == -1) u6AA4(  
{ 5`~PR :dN  
System.err.println("File Length is not known!"); x[a<mk  
} vN`klDJgW[  
else if(nFileLength == -2) ibj87K  
{ vX/T3WV  
System.err.println("File is not access!"); A"L&a l$i  
} #ZB~ x6i6  
else Yt;MV)  
{ <sBbT `  
for(int i=0;i<nStartPos.length;i++) 0yD9SJn  
{ be.*#[  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); E=nIRG|g  
} s.$3j$vT 8  
for(int i=0;i<nEndPos.length-1;i++) sS*3=Yh  
{ U|jSa,}  
nEndPos = nStartPos[i+1]; 4 o Fel.o  
} h&KO<>  
nEndPos[nEndPos.length-1] = nFileLength; j0oR) du  
} k$blEa4  
} sB7# ~p A  
i<#QW'R(  
.%xn&3  
//启动子线程 A1O' |7X  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; MN\HDKN  
for(int i=0;i<nStartPos.length;i++) >T^;MS  
{ jIJ~QpNE  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t'n pG}`tE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2LF/H$] o5  
nStartPos,nEndPos,i); \NPmym_ 6J  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); JMC. w!  
fileSplitterFetch.start(); fp`;U_-&0  
} ;ub;l h3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V<GHpFi0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); X $jWo@  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ZOh`(})hy  
nEndPos = " + nFileLength); b,7k)ND1F  
// fileSplitterFetch[nPos.length-1].start(); EJMM9(DQ7  
,o86}6Ag  
B3 8]~'8  
//等待子线程结束 l9{hq/V  
//int count = 0; GeH#I5y  
//是否结束while循环 g6j?,c|y  
boolean breakWhile = false; 9jM}~XvV  
H\ F :95  
Lt64JH^lz  
while(!bStop) (A9Fhun  
{ 0X6YdW_2X  
write_nPos(); +^60T$  
Utility.sleep(500); geru=7  
breakWhile = true; LBYMCY  
m*&]!mM"0G  
o#3ly-ht  
for(int i=0;i<nStartPos.length;i++) aTH{'mN  
{ +$ 'Zf0U  
if(!fileSplitterFetch.bDownOver) &u$Q4  
{ 'DP1,7  
breakWhile = false; 75T%g!c#  
break; u^^[Q2LDU}  
} 5_GYrR2  
} ?:Uv[|S#>  
if(breakWhile) {$0mwAOH "  
break; DX#Nf""Pw  
<cps2*'  
~Y^+M*   
//count++; Sc]B#/~B  
//if(count>4) +}Dw3;W}m  
// siteStop(); \ 2M_\Q`NY  
} |jGf<Bf5  
rBQ_iB_  
3dg1DR;  
System.err.println("文件下载结束!"); ^O?/yV?4c  
} !|S(Ms  
catch(Exception e){e.printStackTrace ();} 8W*%aOi5+  
} =W(Q34  
n\mO6aJ  
(S>C#A=E\  
//获得文件长度 ,0 M_ Bk"  
public long getFileSize() V(H1q`ao9  
{ )}Hpi<5N  
int nFileLength = -1; B-*+r`@Bd  
try{ Ua:}Vn&!  
URL url = new URL(siteInfoBean.getSSiteURL()); ^UP`%egR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &GpRI(OB/+  
httpConnection.setRequestProperty("User-Agent","NetFox"); YL!P0o13r  
g];!&R-  
p_RsU`[  
int responseCode=httpConnection.getResponseCode(); >^u2cAi3[  
if(responseCode>=400) Snj'y,p[  
{ ~[t[y~Hup  
processErrorCode(responseCode); Cjn#00  
return -2; //-2 represent access is error b6,iZ+]  
} ` 'DmDg  
5AFJC?   
`+]Qz =}  
String sHeader; (p"%O  
4>wP7`/+y  
R$R *'l  
for(int i=1;;i++) Zu*F#s!tUI  
{ m+ =] m_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 8SMxw~9$  
//Utility.log(in.readLine()); s:n6rG  
sHeader=httpConnection.getHeaderFieldKey(i); S\CCrje  
if(sHeader!=null) ?qb}?&1  
{ 2=*H 8'k  
if(sHeader.equals("Content-Length")) OAgniLv  
{ u+9hL4  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); k R?qb6  
break; 1I%w?^sm_  
} /ixp&Z|7  
} Akq2 d;  
else NDN7[7E  
break; nGC/R&  
} =>m<GvQz  
} { a =#B)6  
catch(IOException e){e.printStackTrace ();} W_JlOc!y  
catch(Exception e){e.printStackTrace ();} ld[I}88$  
3/P1!:g9  
'+@=ILj>  
Utility.log(nFileLength); akmkyrz'&  
$zUP?Gq!  
=O~_Q-  
return nFileLength; em y[k  
} J"0`%'*/  
Sh/08+@+L:  
.#EFLXs  
//保存下载信息(文件指针位置)  0HZ{Y9]  
private void write_nPos() 8'[~2/  
{ (^ J I%>  
try{ b!+hH Hv:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); -M\<nx  
output.writeInt(nStartPos.length); 4j-Xi  
for(int i=0;i<nStartPos.length;i++) l5~os>  
{ d9k0F OR1  
// output.writeLong(nPos); zrvF]|1UP  
output.writeLong(fileSplitterFetch.nStartPos); 1a/++4O.|  
output.writeLong(fileSplitterFetch.nEndPos); YX!iL6?~  
} N"Z{5A  
output.close(); 2IK}vDsis  
} %U/(|wodd  
catch(IOException e){e.printStackTrace ();} &j;wCvE4+  
catch(Exception e){e.printStackTrace ();} ez7A4>/  
} R8K&R\  
%:i7s-0w  
<;lkUU(WT2  
//读取保存的下载信息(文件指针位置) [|v][Hwv  
private void read_nPos() \P[Y`LYL  
{ )j6~Wy@4  
try{ ]>!K3kB  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); }H53~@WP>  
int nCount = input.readInt(); oe^I  
nStartPos = new long[nCount]; 9p]QM)M  
nEndPos = new long[nCount]; HVRZ[Y<^  
for(int i=0;i<nStartPos.length;i++) Usvl}{L[  
{ p#-Z4-`  
nStartPos = input.readLong(); rm7ANMB:  
nEndPos = input.readLong(); [z:!j$K  
} &0d# Y]D4`  
input.close(); x5pdS:  
} _T60;ZI+^  
catch(IOException e){e.printStackTrace ();} 'B |JAi?  
catch(Exception e){e.printStackTrace ();} 6%'QjwM_  
} u*eV@KK!  
/l3V3B7  
7^avpf)>  
private void processErrorCode(int nErrorCode) 0S"mVZ*P  
{ hDDn,uzpd  
System.err.println("Error Code : " + nErrorCode); J4hL_iCQ  
} fuW\bo3  
U4'#T%*  
w?L6!)oiz  
//停止文件下载 #<fRE"v:Q  
public void siteStop() p%ki>p )E|  
{ gt) I(  
bStop = true; Xg6Jh``  
for(int i=0;i<nStartPos.length;i++) soxc0OlN  
fileSplitterFetch.splitterStop(); yxPazz  
2Ah#<k-gC;  
{p2!|A&a  
} +|3@=.V  
} RH W]Z Pr<  
//负责部分文件的抓取 AI2)g1m  
**FileSplitterFetch.java z^B,:5Tt  
*/ D\v+wp.  
package NetFox; +Ze} B*0  
hPkp;a #  
iI T;K@&  
import java.io.*; iT+8|Yia  
import java.net.*; #\{l"-  
E_rI?t^  
Fe*R  
public class FileSplitterFetch extends Thread { .^`{1%  
u,ho7ht3(  
WCZjXDiwJ  
String sURL; //File URL :U|1xgB  
long nStartPos; //File Snippet Start Position )rU  
long nEndPos; //File Snippet End Position e+7"/icK  
int nThreadID; //Thread's ID u[;\y|75  
boolean bDownOver = false; //Downing is over NWESP U):w  
boolean bStop = false; //Stop identical 0D.Mke )  
FileAccessI fileAccessI = null; //File Access interface Oi.C(@^(  
tAd%#:K  
,L2ZinU:  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException l\H=m3Bg  
{ d0!5j  
this.sURL = sURL; 5Pc;5 o0C  
this.nStartPos = nStart; 8Al{+gx@?  
this.nEndPos = nEnd; r8?gD&c}  
nThreadID = id; 8 /]S^'>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :LQYo'@yB  
} g/d<Zfq<{  
Vr)S{k-Q  
gx/,)> E.  
public void run() =ZznFVJ`={  
{ 2QcOR4_V  
while(nStartPos < nEndPos && !bStop) Evq IcZ  
{ J[|y:N  
y-b%T|p9  
1s&zMWC  
try{ u/0h$l  
URL url = new URL(sURL); k9R4Y\8P  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); NN{?z!  
httpConnection.setRequestProperty("User-Agent","NetFox"); yPBZc h%-  
String sProperty = "bytes="+nStartPos+"-"; .NC!7+1m  
httpConnection.setRequestProperty("RANGE",sProperty); s]0{a.Cpv  
Utility.log(sProperty); !PlEO 2at  
Dj?> <@  
bHnT6Icom  
InputStream input = httpConnection.getInputStream(); nc29j_Id  
//logResponseHead(httpConnection); e2Pcm_Ahv*  
q9K)Xk$LF  
|3b^~?S  
byte[] b = new byte[1024]; r|8d 4  
int nRead; k .;j  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) a.\:T,cP>  
{ 3ZPWze6  
nStartPos += fileAccessI.write(b,0,nRead); sE<V5`Z=  
//if(nThreadID == 1) 7aRi5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !*&V- 4  
} Pj^{|U21  
05#1w#i  
PdFKs+Z`  
Utility.log("Thread " + nThreadID + " is over!"); F,F4nw<W  
bDownOver = true;  qA7>vi%  
//nPos = fileAccessI.write (b,0,nRead); k"%~"9  
} eKgBy8tNS0  
catch(Exception e){e.printStackTrace ();} p4rL}Jm&  
} ;`4&Rm9n?  
} >2)OiQ`zg  
 DPxM'7  
r,3DTBe  
//打印回应的头信息 ?3,:-"(@p  
public void logResponseHead(HttpURLConnection con) jOunWv|  
{ ZQsJL\x[UK  
for(int i=1;;i++) 1=c\Rr9]  
{ ZU4nc3__  
String header=con.getHeaderFieldKey(i); ,-c6dS   
if(header!=null) OZF rtc+  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); M)+H{5bt  
Utility.log(header+" : "+con.getHeaderField(header)); /Iy]DU8  
else A`$%SVgFV^  
break; ^mDe08. %b  
} VcYrK4  
} ek\ xx  
rU:`*b<  
8W(*~}ydYY  
public void splitterStop() Vb;*m5,?:  
{ t9`.bx8  
bStop = true; dq6m>;`  
} _/$Bpr{R  
(N6i4 g6  
k Z .gO  
} sf qL|8  
\ a<h/4#|  
k,6f &#x  
/* jD]~ AwRJ  
**FileAccess.java N^G Mp,8  
*//文件访问(定位,写) J?1 uKR  
package NetFox; ::lKL  
import java.io.*; wu!59pL  
r'r%w#=`t  
{hjhL: pg  
public class FileAccessI implements Serializable{ %P/Jq#FE .  
S(l O(gY  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 )p0^zv{  
RandomAccessFile oSavedFile; l`{\"#4  
long nPos; CS5?Ti6  
'RR~7h  
(,Q7@s  
public FileAccessI() throws IOException ;-lXU0}&  
{ .Iw AK/QS  
this("",0); drP=A~?&:  
} X*XZb F"=  
KnQ*vM*VM  
Jy:Qlx`  
public FileAccessI(String sName,long nPos) throws IOException gQg"j)  
{ py!|\00}  
oSavedFile = new RandomAccessFile(sName,"rw"); t;Sb/3  
this.nPos = nPos; )h4 f\0  
oSavedFile.seek(nPos); 5"@*?X K^  
} Ad8n<zt|  
wLH>:yKUU  
bKY7/w<dP  
public synchronized int write(byte[] b,int nStart,int nLen) gIa+5\qYY  
{ )3}9K ^jS  
int n = -1; )JLdO*H  
try{ nI-w}NQ  
oSavedFile.write(b,nStart,nLen); g" DG]/ev  
n = nLen; *boR`[Ond  
} SiRaFj4s"  
catch(IOException e) KIf dafRL  
{ gMmaK0uhS  
e.printStackTrace (); eS\Vib  
} SCHP L.n  
vn!3l1\+J  
5h-SCB>P  
return n; Tod&&T'UW  
} &\WSQmtto  
BC#C9|n  
xp)sBM7A  
} T{.pM4Hd  
?m}s4a  
3>AMII  
/* /{aj}M0kN  
**SiteInfoBean.java `l ^9/_g'6  
*/ L-WT]&n_  
package NetFox; )._;~z!  
Fn;SF4KOm  
q4:o#K#  
public class SiteInfoBean { ,+DG2u  
8,4"uuI  
{ ]{/t-=  
private String sSiteURL; //Site's URL /<=u\e'rE  
private String sFilePath; //Saved File's Path QL&ZjSN  
private String sFileName; //Saved File's Name ]Ji.Zk  
private int nSplitter; //Count of Splited Downloading File v5#j Z$<F  
uM IIYS  
feDlH[$  
public SiteInfoBean() t ;;U}  
{//nSplitter的缺省值为5 q460iL7yF}  
//default value of nSplitter is 5 EzM ?Nft  
this("","","",5); N=5a54!/  
} w !-gJmX>  
O|{d[eX  
8B K(4?gC  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) qFCOUl  
{ xw,IJ/E$1  
sSiteURL= sURL; |O\s|H  
sFilePath = sPath; iAEbu&XG  
sFileName = sName; +US!YU  
this.nSplitter = nSpiltter; :Uzm  
M#4p E_G  
)9{0]u;9  
} \^J%sf${  
(&F}/s gbi  
XH4  
public String getSSiteURL() %+W{iu[|  
{ _~l5u8{^6  
return sSiteURL; ;;OAQ`  
} O>b C2;+s  
X1x#6 oi  
.PIL +x*]N  
public void setSSiteURL(String value) BDW^7[n  
{ X8a/ `Y,  
sSiteURL = value; s^G.]%iU  
} A@!qv#'  
'j8:vq^d  
ar!R|zmf  
public String getSFilePath() 58tARLDr  
{ *k(XW_>  
return sFilePath; y*jp79G  
} jjB~G^n  
m<T%Rb4?@  
O~#!l"0 L+  
public void setSFilePath(String value) `!;_ho  
{ gZ3u=uME  
sFilePath = value; Xv5wJlc!d  
} D[[|")Fn  
r"gJX  
^B.5GK)!  
public String getSFileName() p?%y82E  
{ c \J:![x  
return sFileName;  ul6]!Iy  
} qdJ=lhHM}  
?4#Li~q  
F4-$~ v@  
public void setSFileName(String value) K*vt;L  
{ In"ZIKaC  
sFileName = value; @su^0 9n  
} |/|5UiX7  
b5dD/-Vj  
7 UKh688  
public int getNSplitter() KI iO  
{ 6EoMt@7g  
return nSplitter; O-0x8O^B  
} ?DS@e@lx  
f M :]&  
(?1y4M  
public void setNSplitter(int nCount) B?gOHG*vd>  
{ $Ps|HN  
nSplitter = nCount; Af~$TyX  
} >^?u .gM3  
} `t>l:<@%  
iJ)_RSFK  
9IdA%RM~mH  
/* >UTBO|95y  
**Utility.java #K_ii)n  
*/ [B*x-R[FI  
package NetFox; HTv2#  
}<0BX\@I  
}^ ~F|  
public class Utility { !I{0 _b{  
p}z<Fdu 0  
hn7# L  
public Utility() ~f&E7su-6+  
{ + /4A  
64 wv<r]5j  
}1L4 "}L.  
} )Yh+c=6 ?  
38Mv25N  
//线程睡眠 x}wG:K  
public static void sleep(int nSecond) a_^\=&?'  
{ /Vx7mF:  
try{ HYD'.uj  
Thread.sleep(nSecond); B-Ll{k^  
} ]`!>6/[  
catch(Exception e) ,a{P4Bq  
{ ;IvY^(YS@;  
e.printStackTrace (); 8rAg \H3E  
} ?8H8O %Z8  
} G/y5H;<9M  
]!W=^!  
//日志 A_"w^E{P  
public static void log(String sMsg) U|H=Y"pL  
{ 6##_%PO<m  
System.err.println(sMsg); ;0]aq0_#(  
} xk9%F?)  
IEL%!RFG  
6fE7W>la  
public static void log(int sMsg) [t m_Mg  
{ b i',j0B  
System.err.println(sMsg); XFVE>/H  
} K C*e/J  
} y;m|  
i<C*j4qQ  
UP$.+<vm  
/* w8")w*9Lmg  
**TestMethod.java 9d0@wq.  
*/ =g7x' kN  
package NetFox; ;Zcswt8]u  
ih-#5M@  
gMi0FO'  
public class TestMethod { ]\-A;}\e  
ch*8B(:  
>4x(e\B  
public TestMethod() { T/[cu<  
{ ///xx/weblogic60b2_win.exe X~b X5b[P  
try{ B-RjMxX4>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Y,qI@n<  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); hk;5w{t}}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); h ]5(].  
fileFetch.start(); Q^P}\wb>  
} 9 &dtd  
catch(Exception e){e.printStackTrace ();} '0;l]/i.  
^ox=HNV  
j.[.1G*("  
} zF`0J  
&Q/W~)~  
F>Ah0U0  
public static void main(String[] args) _O)>$.^6  
{ :I]Mps<  
new TestMethod(); B9_ X;c  
} !NK1MU?T)  
} ~Py`P'+  
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