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http断点续传简单实现(java)

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/* G'(8/os{  
**SiteFileFetch.java >=d%t6 %(  
*/ R_B`dP<"~Y  
package NetFox; ~c${?uf   
import java.io.*; {J]x81}*;  
import java.net.*; 7(B"3qF8|  
N.?)s.D(  
a$]i8AeG  
public class SiteFileFetch extends Thread { jn+BH3e  
Bb*P);#.K  
-}9>#<v  
SiteInfoBean siteInfoBean = null; //文件信息Bean ~ }?*v}  
long[] nStartPos; //开始位置 X^)v ZL?  
long[] nEndPos; //结束位置 qORRpWyx&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Mc<O ~  
long nFileLength; //文件长度 ObSRd$M  
boolean bFirst = true; //是否第一次取文件 aLO'.5 ~^  
boolean bStop = false; //停止标志 Gk]6WLi  
File tmpFile; //文件下载的临时信息 ?(>fB2^  
DataOutputStream output; //输出到文件的输出流 eY8rm  
d< b,].  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) */y (~O6  
public SiteFileFetch(SiteInfoBean bean) throws IOException .a7!*I#g  
{ j S<."a/n  
siteInfoBean = bean; WbGN 5?9Q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @q+X:K5b  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1[4 0\sM  
if(tmpFile.exists ()) PEPf=sm  
{ v-!^a_3Ui  
bFirst = false; Og<nnq  
read_nPos(); A_2oQ*  
} L<Q>:U.@\  
else )GR4U8<>g  
{ TcOmBKps'  
nStartPos = new long[bean.getNSplitter()]; @y(<4kLz  
nEndPos = new long[bean.getNSplitter()]; CC,CKb  
} Ms14]M[\  
4Bk9d\z  
C(}N*e1  
w=QW8q?  
} KYR64[1  
t>JPK_b0  
`w EAU7m:  
public void run() Z Z9D6+R  
{ 9;R'Xo=y  
//获得文件长度 tWaM+W  
//分割文件 VQ^}f/A  
//实例FileSplitterFetch Xsd+5="{N  
//启动FileSplitterFetch线程 u:M)JG  
//等待子线程返回 bL0>ul"  
try{ ^n9)rsb  
if(bFirst) 90UZ\{">  
{ .A apO}{  
nFileLength = getFileSize(); `XrF ,  
if(nFileLength == -1) :EV*8{:aLU  
{ <CGABlZ  
System.err.println("File Length is not known!"); zy'cf5k2  
} JXq l=/%  
else if(nFileLength == -2) >$G'=N:=X&  
{ B3'-:  
System.err.println("File is not access!"); x`JhNAO>  
} !dGSZ|YZ  
else Ft 6{g JBG  
{ D2]i*gs  
for(int i=0;i<nStartPos.length;i++) dZ `c  
{ _p;=]#+c&  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); E~`l/ W  
} 8C8,Q\WV(~  
for(int i=0;i<nEndPos.length-1;i++) q}cm"lO$  
{ )<[)7`  
nEndPos = nStartPos[i+1]; [^0 S#,L  
} pYz\GSd  
nEndPos[nEndPos.length-1] = nFileLength; N;R I A  
} T7?cnK"  
} 0[.T`tpN'  
^0HgE;4  
 ,$(a,`s)  
//启动子线程 2`U+ !  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; D+"+m%^>C  
for(int i=0;i<nStartPos.length;i++) v4vIcHDs  
{ X ;Cl8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;S+]Z!5LT  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), x&*2R#Ai  
nStartPos,nEndPos,i); og`K! d~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); rmJ`^6V  
fileSplitterFetch.start(); NM+ (ss'  
} >>%E?'9A  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3gs!ojG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #83pitcc  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", q!AcM d\  
nEndPos = " + nFileLength); (D2N_l(`<  
// fileSplitterFetch[nPos.length-1].start(); .O6(QI*  
%/w%A:y#&  
Ni>!b6 Z`[  
//等待子线程结束 w@x||K=Z  
//int count = 0; v,d'SR.  
//是否结束while循环 /wU4^8Hz  
boolean breakWhile = false; M`p[ Zq  
 w\y)  
<op|yh3Jkk  
while(!bStop) w7Ij=!)  
{ 11?d,6Jl  
write_nPos(); #oJ%i+V  
Utility.sleep(500); =[LUOOR*]  
breakWhile = true; 8 `}I]  
_~bG[lX!  
mr>dZ)  
for(int i=0;i<nStartPos.length;i++) ffR<G&"n~b  
{ z!aU85y  
if(!fileSplitterFetch.bDownOver) 0DX)%s,KO  
{ @1s 2# )l(  
breakWhile = false; Vp1Ff  
break; s'/ZtH6>C  
} cYz|Ux  
} yq12"Rs  
if(breakWhile) #Wq@j1?  
break; #vzt6x@*  
6e%ZNw{#=  
=0mn6b9-=  
//count++; Axw+zO  
//if(count>4) h^'+y1  
// siteStop(); _b9>ZF~  
} rA /T>ZM  
eFC~&L;  
a+<{!+3v  
System.err.println("文件下载结束!"); ,c|Ai(U  
} EbnV"]1  
catch(Exception e){e.printStackTrace ();} <=]:ED $V@  
} )yUSuK(Vu  
95sK;`rE+  
3|BB#;  
//获得文件长度 +NTC!/  
public long getFileSize() M8${&&[;  
{ t8.^YTI  
int nFileLength = -1; C(n_*8{  
try{ cUr5x8<W).  
URL url = new URL(siteInfoBean.getSSiteURL()); _ ($U\FW  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7{p6&xXx  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~p x2kHZ  
lBLL45%BIN  
lX64IvG8+o  
int responseCode=httpConnection.getResponseCode(); `#?]g!  
if(responseCode>=400) 'u3,+guz  
{ F#a'N c9  
processErrorCode(responseCode); w%$J<Z^-?  
return -2; //-2 represent access is error %ZX3:2  
} Ge1"+:tbJ  
~cSE 9ul  
)i<Qg.@MX  
String sHeader; >[S\NAE>  
$:D\yZ,  
>,x``-  
for(int i=1;;i++) lJt?0;gn  
{ WmuYHEU  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 4VhKV JX  
//Utility.log(in.readLine()); QBjvbWoIG(  
sHeader=httpConnection.getHeaderFieldKey(i); (Q"~bP{F  
if(sHeader!=null) >cH}sNHy  
{ 7 lu_E.Bv  
if(sHeader.equals("Content-Length")) 4wPP/`  
{ 7n7UL0Oc1  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?@QcKQ@  
break; ~^l;~&  
} x#fv<Cj4  
} KebC$g@W  
else A'n{K#  
break; WNSEc%  
} J7wIA3.O  
} o,'Fz?[T%  
catch(IOException e){e.printStackTrace ();}  CP Ju=  
catch(Exception e){e.printStackTrace ();} Va^(cnwa  
yC7lR#N8j0  
lT_dzO  
Utility.log(nFileLength); .9q`Tf  
QObHW[:F  
8|tnhA]~  
return nFileLength; 3*N0oc^m  
} 3x>Y  
f1 `E-  
JG@Zb}b  
//保存下载信息(文件指针位置) xn anca  
private void write_nPos() ?N&s .  
{ 1ezBn ZJg  
try{ T3PwM2em_`  
output = new DataOutputStream(new FileOutputStream(tmpFile)); d?aZk-|c  
output.writeInt(nStartPos.length); ,3W,M=j)  
for(int i=0;i<nStartPos.length;i++) ])?[9c  
{ | CPyCM$  
// output.writeLong(nPos); :A5h<=[  
output.writeLong(fileSplitterFetch.nStartPos); .@psW0T%  
output.writeLong(fileSplitterFetch.nEndPos); NtkZ\3  
} @4$la'XSx  
output.close(); LeYI<a@n@$  
} :(;ho.zz  
catch(IOException e){e.printStackTrace ();} $Y8iT<nP  
catch(Exception e){e.printStackTrace ();} 7#C3E$gn?  
} ,%U\@*6=  
Y^eF(  
!e}4>!L,(^  
//读取保存的下载信息(文件指针位置) o_&Qb^W  
private void read_nPos() |k]fY*z(  
{ [<X ~m  
try{ s?PB ]Tr  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =z\/xzAwX  
int nCount = input.readInt(); B^C 5?  
nStartPos = new long[nCount]; j |LOg  
nEndPos = new long[nCount]; 5:%`&B\  
for(int i=0;i<nStartPos.length;i++) 4c<\_\\ck  
{ )\ J~KB4  
nStartPos = input.readLong(); T1;>qgp4b  
nEndPos = input.readLong(); u56F;y  
} 1i;Cw/mr  
input.close(); p tlag&Z  
} )1f.=QZN^;  
catch(IOException e){e.printStackTrace ();} AsR}qqG  
catch(Exception e){e.printStackTrace ();} Wz;@Rl|F  
} y 7z)lBy\  
%`lLX/4~  
2yVQqwQ m  
private void processErrorCode(int nErrorCode) (V0KmNCW`  
{ t:n$9WB)  
System.err.println("Error Code : " + nErrorCode); ,fvhP $n  
} s1p<F,  
n>xuef   
iB+ _+A  
//停止文件下载 @>+`1C  
public void siteStop() 5m\)82s  
{ 5>h/LE]"  
bStop = true; 4GS:kfti  
for(int i=0;i<nStartPos.length;i++) I>lblI$7  
fileSplitterFetch.splitterStop(); 37 *2/N2  
X39%O'  
,_ @) IN  
} Uurpho_~  
} h{^MdYJ  
//负责部分文件的抓取 "g5MltH  
**FileSplitterFetch.java NT{ 'BJ  
*/ izLB4pk$  
package NetFox; #)4p ,H  
S~M/!Xb  
ps*iE=D  
import java.io.*; umt(e:3f5  
import java.net.*; -/_hO$|W  
le6eorK8  
0Z{u;FI  
public class FileSplitterFetch extends Thread { DPfN*a-P(  
,nJCqX~ /G  
$g\p)- aU  
String sURL; //File URL /sSM<r]5j  
long nStartPos; //File Snippet Start Position @eYD@!  
long nEndPos; //File Snippet End Position f6m h_l  
int nThreadID; //Thread's ID G<Urj+3/Xo  
boolean bDownOver = false; //Downing is over 3&R1C>JS ]  
boolean bStop = false; //Stop identical fONycXM]  
FileAccessI fileAccessI = null; //File Access interface f7Gs1{  
57EL&V%j  
X$eR RSW  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException B[5<&  
{ Gz2\&rmN  
this.sURL = sURL; QV -ZP'e^  
this.nStartPos = nStart; m?=J;r"Re  
this.nEndPos = nEnd; P` y.3aK  
nThreadID = id; (]-RL A>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "ZuA._  
} zuF]E+  
lU`t~|>r+  
,M :j5  
public void run() p{&o{+c  
{ K14v6d  
while(nStartPos < nEndPos && !bStop) xu@xP5GB^  
{ WA5.qw  
#-l+c u{  
rj/nn)vv;  
try{ #;h> x  
URL url = new URL(sURL); ]2_=(N\Kt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q)5V3Q]@^  
httpConnection.setRequestProperty("User-Agent","NetFox"); TXqtE("BDl  
String sProperty = "bytes="+nStartPos+"-"; !E^\)=E)P  
httpConnection.setRequestProperty("RANGE",sProperty); XE#$|Z  
Utility.log(sProperty); ycf)*0k  
2B+qS'OT  
hLT?aQLx  
InputStream input = httpConnection.getInputStream(); H%{k.#O  
//logResponseHead(httpConnection); :bkmm,%O  
7_J0[C!G  
}/jWa |)f  
byte[] b = new byte[1024]; gI/(hp3ob  
int nRead; 6UU<:KH  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 0JW =RW  
{ u.}H)wt  
nStartPos += fileAccessI.write(b,0,nRead); j%gle%_  
//if(nThreadID == 1) hb1eEn  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !1l~'/r  
} I(b]V!mj:  
:g{ybTSEe  
>b8-v~o{  
Utility.log("Thread " + nThreadID + " is over!"); ]$U A5/a  
bDownOver = true; <VhD>4f{]  
//nPos = fileAccessI.write (b,0,nRead); wWM[Hus  
} /$9We8  
catch(Exception e){e.printStackTrace ();} (^58$IW71  
} zX6Q7Bc  
} 4r#4h4`y|  
"i&9RA! 1  
f[?JLp   
//打印回应的头信息 @0%[4  
public void logResponseHead(HttpURLConnection con) *DQa6,b  
{ /)sP<WPQ 6  
for(int i=1;;i++) F6_e n z  
{  hRqr  
String header=con.getHeaderFieldKey(i); H`jnChD:M'  
if(header!=null) ^OK;swDW  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 'f8'|o)  
Utility.log(header+" : "+con.getHeaderField(header)); ;_0frX  
else $y%IM`/w  
break; I/u>Gt  
} ,x?Jrcx~'C  
} < Yc)F.:  
-8v:eyc  
{: =]J4]  
public void splitterStop() H;#C NB<e  
{ +K ,T^<F;  
bStop = true; 7tne/Yz  
} szD9z{9"y  
Az/B/BLB  
JW"n#sR4  
} w8zr0z  
}|wC7*^)  
*d31fBCk%  
/* Zh_3ydMD1  
**FileAccess.java 5ka6=R(r  
*//文件访问(定位,写) WT}x Cni  
package NetFox; un}!&*+  
import java.io.*; D'#,%4P,e\  
w%(D4ldp   
P1 |3%#c  
public class FileAccessI implements Serializable{ 9<o*aFgCa  
FytGg[#]  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 2 ]n4)vv,  
RandomAccessFile oSavedFile; +`!>lo{X  
long nPos; j|{ n?  
Q x&7Ceu"  
>O0<u  
public FileAccessI() throws IOException ,[3}t%Da  
{ fP 3t0cp  
this("",0); PJ,G_+b!  
} (-VH=,Md  
ux)Wh.5  
+W8kMuM!  
public FileAccessI(String sName,long nPos) throws IOException Hm+VGH'H?  
{ 2'Raj'2S4  
oSavedFile = new RandomAccessFile(sName,"rw"); 8t |?b  
this.nPos = nPos; !vuun |  
oSavedFile.seek(nPos); R_"6E8N  
} #}Bv/`t  
xm tD0U1  
"G Jhx/zt  
public synchronized int write(byte[] b,int nStart,int nLen) ! 6R|  
{ s+^1\  
int n = -1; 4\j1+&W   
try{ 1B$8<NCQ=?  
oSavedFile.write(b,nStart,nLen); mRN[l j  
n = nLen; # wyjb:Ql  
} [}4\CWM  
catch(IOException e) l-5O5|C  
{ rl-#Ez  
e.printStackTrace (); cfy9wD  
} n^nQrRIp  
(%G>TV  
_qH]OSo  
return n; B_C."{G  
} 0^6}s1d_  
C#P>3"  
bAUYJPRpy  
} =w<iYO  
,V''?@  
u++a0>N  
/* #A:^XAU1Z@  
**SiteInfoBean.java +~7[T/v+n  
*/ [8vqw(2Tm(  
package NetFox; `%~f5<  
dP"cm0  
/=QsZ,~xo  
public class SiteInfoBean { Wxgs66   
=@nW;PUZ  
G0Z$p6z  
private String sSiteURL; //Site's URL @Ph'!  
private String sFilePath; //Saved File's Path ]qx!51S  
private String sFileName; //Saved File's Name ^;$9>yi1  
private int nSplitter; //Count of Splited Downloading File "#pN  
C;ME"4,(  
:Ye~I;" 8  
public SiteInfoBean() &E@mCQ1  
{//nSplitter的缺省值为5 #v4^,$k>  
//default value of nSplitter is 5 fT<3~Z>m  
this("","","",5); To-$)GQ@W  
} #IeG/t(  
\*pS 4vy5x  
p*JP='p  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @P[%6 d  
{ mS.!lkV  
sSiteURL= sURL; Ds@K%f(.?w  
sFilePath = sPath; >b~Q%{1  
sFileName = sName; !Nbi&^k B  
this.nSplitter = nSpiltter; ,t|_Nc  
MfA%Xep  
V'9OGn2v  
} slLTZ]  
xscR Bx  
~8'HX*B]z  
public String getSSiteURL() |1Nz8Vr.  
{ mn(MgJKQ\  
return sSiteURL; ANR611-a  
} [P]M)vJ**  
Q[lkhx|.B  
c~6ywuq+M`  
public void setSSiteURL(String value) I,V'J|=j  
{ $>Gf;k  
sSiteURL = value; [3qJUJM  
} ;cb='s  
r%LG>c`^  
[p )2!]y  
public String getSFilePath() y }h2  
{ YL[y3&K  
return sFilePath; 2(GLc*B>  
} =wa5\p/  
e)i-$0L"  
K%SfTA1TCB  
public void setSFilePath(String value) D:(h^R0;  
{ "T}HH  
sFilePath = value; M[e{(iQ:  
} GF0Utp:Zf;  
rNgAzH  
ul"Z% 1]  
public String getSFileName() QdIoK7J 9  
{ zeH=py[n  
return sFileName; fJi?~[5<  
} .o8pC  
sEx\7tK  
eqpnh^0}d  
public void setSFileName(String value) ^!O2Fw  
{ \d w["k  
sFileName = value; C+gu'hD  
} 1i Q(q\%  
|D8c=c%  
g$8a B{)  
public int getNSplitter() 8)J,jh9q  
{ "||G`%aO+t  
return nSplitter; Z3iX^  
} RP wP4Z  
> !HC ?  
m h|HEkM  
public void setNSplitter(int nCount) ry4:i4/[  
{ >*}m .'u  
nSplitter = nCount; > 'JWW*Y!  
} k59.O~0V  
} 6<UI%X  
IZ]L.0,  
$U%N$_k?  
/* oXqx]@7  
**Utility.java tNW0 C]  
*/ ^ X<ytOd5  
package NetFox; 3N{ ZX{}  
E8We2T[^M  
|U="B4  
public class Utility { ||4++84{  
y(Q.uYz*  
3<6P^p=I  
public Utility() (' i_Xe  
{ 79U 7<]-!  
;] #Q!  
N37#V s  
} 8V:yOq10  
0y#TGM|0D  
//线程睡眠 x 0L,$Ol  
public static void sleep(int nSecond) glWa?#1  
{ /A`Ly p#  
try{ jt",\%j  
Thread.sleep(nSecond); N)$yBzN  
} $EuI2.o  
catch(Exception e) y#e<]5I  
{ O[&G6+  
e.printStackTrace (); p2Fi(BW*q  
} q.RW_t~  
} C6,W7M[c  
lb#`f,r>  
//日志 ,An*w_  
public static void log(String sMsg) v>mr  
{ %C*h/AW)'  
System.err.println(sMsg); 9{{CNy p  
} o=do L{ #  
&v_b7h  
{I"d"'h  
public static void log(int sMsg) c::Vh  
{ HoKN<w  
System.err.println(sMsg); +JL"Z4b@R}  
} g ??@~\Ov  
} p:^;A/D  
5nG$6Hw  
%g%#=a;]q  
/* 9=;ETLL "  
**TestMethod.java ,u<aKae  
*/ E+E.z?>S  
package NetFox; |Ok1E  
uY=}w"Db  
7~ok*yGw  
public class TestMethod { `=~d^wKYJ3  
\9dC z;  
9#niMv9  
public TestMethod() }!RFX)T  
{ ///xx/weblogic60b2_win.exe ,LJX  
try{ _p=O*$b.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); K)t+lJ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }))JzrqAe  
SiteFileFetch fileFetch = new SiteFileFetch(bean); To19=,:  
fileFetch.start(); m/W)IG>  
} %y;Cgo[  
catch(Exception e){e.printStackTrace ();} F>A&L8  
kculHIa\.  
|JH1?n  
} p)=Fi}#D\  
Yv jRJ  
bi[gyl#  
public static void main(String[] args) c>RS~/Y  
{ ~*h` ?A0  
new TestMethod(); h+h`0(z  
} p,+$7f1S  
} w">p 8  
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