http断点续传简单实现（java)

/* 1g+<`1=KT  
**SiteFileFetch.java dQb?Zi7g  
*/ lNw?}H  
package NetFox;
kzu=-@s  
import java.io.*; )2S\:&x  
import java.net.*; DQ$/0bq   
V"XN(Fd^  
,8seoX^  
public class SiteFileFetch extends Thread { D?R z|  
cCIEG e6  
mLO6`]p{H  
SiteInfoBean siteInfoBean = null; //文件信息Bean tK*f8X+q  
long[] nStartPos; //开始位置 ^=j$~*(LmX  
long[] nEndPos; //结束位置 lVHJ}(<'p  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 WP9=@X Z  
long nFileLength; //文件长度 z7o59&  
boolean bFirst = true; //是否第一次取文件 o-_a0j  
boolean bStop = false; //停止标志 D6pk!mS  
File tmpFile; //文件下载的临时信息 Z)~2{)  
DataOutputStream output; //输出到文件的输出流 _JS'~JO3{  
$9/r*@bu8d  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） $}@ll^  
public SiteFileFetch(SiteInfoBean bean) throws IOException B=7L+6  
{ WD:5C3;  
siteInfoBean = bean; 9)qx0  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6gXc-}dp  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); e9hQJ 1{)x  
if(tmpFile.exists ()) s#ykD{Z  
{ *0@e_h  
bFirst = false; /VQ<}S[k}-  
read_nPos(); x,
+zw9  
} [@czvPi  
else AyUVsIuPT=  
{ vjb{h'v  
nStartPos = new long[bean.getNSplitter()]; B4C`3@a  
nEndPos = new long[bean.getNSplitter()]; $Fj7'@1(  
} dj#<,e\  
OB%y'mo7]  
fi1UUJ0 U;  
-c tZ9+LL  
} Qa=;Elp:[  
})Jp5vv  
_]g6 3q  
public void run() s$;v )w$  
{ UZ$p wjC  
//获得文件长度 ;%}  
//分割文件 J{Jxb1:c  
//实例FileSplitterFetch 4{TUoI6ii  
//启动FileSplitterFetch线程 4{V=X3,x  
//等待子线程返回 <Ip}uy[Y  
try{ j,Y=GjfGM  
if(bFirst) W$W7U|Z9y+  
{ chy7hPxC;  
nFileLength = getFileSize(); )u$A!+fo  
if(nFileLength == -1) btOC\bUMfD  
{ N^)OlH  
System.err.println("File Length is not known!"); ZHT.+X:_  
} &^Io\  
else if(nFileLength == -2) H5n"!!  
{ Q["}U7j  
System.err.println("File is not access!"); pVr,WTr6E  
} fqi584  
else {,m!%FDL  
{ L_(|5#IDw  
for(int i=0;i<nStartPos.length;i++) J<2N~$  
{ ]du pU"VV  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "-9YvB#  
} ^>>
Naid  
for(int i=0;i<nEndPos.length-1;i++) ?Gb 18m  
{ li'#< "R?'  
nEndPos = nStartPos[i+1]; Z1&8U=pax  
} \6o ~ i  
nEndPos[nEndPos.length-1] = nFileLength; d%<Uh(+:  
} 8p5
u1 ;2  
} <B)lV'!Bd  
QS[%`-dR2  
n%Fa;!S  
//启动子线程 \(Iy>L.  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; a}yJ$6xi  
for(int i=0;i<nStartPos.length;i++) {x+jFj.  
{ )gE:@3  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qVf~\H@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), rl4-nA  
nStartPos,nEndPos,i); }Vt5].TA  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {YkW5zC(L  
fileSplitterFetch.start(); wi!Ml4Sb  
} pl%ag~i5  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), W6Hiqu+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); (t <Um Vd  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8u>E(Vmpu  
nEndPos = " + nFileLength); nD!^0?  
// fileSplitterFetch[nPos.length-1].start(); ZEB1()GB  
%FwLFo^v  
PffRV7qU0  
//等待子线程结束  @>B
FhH  
//int count = 0; T =:^k+  
//是否结束while循环 E|No$QO
)  
boolean breakWhile = false; ]_-<[0  
B!,})F$x  
T^"d%au  
while(!bStop) kWWb<WRW:  
{ hI"I#(*jA%  
write_nPos(); s3q65%D  
Utility.sleep(500); _:{XL c  
breakWhile = true;  @521zi  
zITXEorF!J  
qh=lF_%uj  
for(int i=0;i<nStartPos.length;i++) &AW?!rH  
{ `
jP6;i  
if(!fileSplitterFetch.bDownOver) X/?3ifP6I  
{ L./
UgeZ  
breakWhile = false; Qq5)|m  
break; ^K3{6}]  
} Q?vGg{>  
} *'Ch(c:rtH  
if(breakWhile) (HY|0Bgr  
break; x;ujR<  
&D/_@\ 0  
yHCBf)N7\  
//count++; 2Ddrxc>48  
//if(count>4) J6jrtLh  
// siteStop(); X_XqT  
} #bnFR  
REw!@Y."  
 pCv=rK@  
System.err.println("文件下载结束！"); 2+0'vIw}  
} zp d4
uto5  
catch(Exception e){e.printStackTrace ();} A\WgtM  
} gCd9"n-e  
zc(-dMlK  
?!Y2fK=h0  
//获得文件长度 N~SG=\rP;o  
public long getFileSize() # *\PU  
{ r3#H]c  
int nFileLength = -1; VaH#~!  
try{ UeE&rA]  
URL url = new URL(siteInfoBean.getSSiteURL()); `6UW?1_Z5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9hcZbM]  
httpConnection.setRequestProperty("User-Agent","NetFox"); \s[Uq  
-8g ;t3z  
qW),)i  
int responseCode=httpConnection.getResponseCode(); *2@Ne[dYEF  
if(responseCode>=400) <UeO+M(  
{ 7)~/`w)P  
processErrorCode(responseCode); /z6NJ2jb  
return -2; //-2 represent access is error ]e R1 +Nl  
} Aj-}G^>#  
Dg\fjuK9  
a Z ^SK|E  
String sHeader; WnA]gyc  
`XQM)A  
,_p_p^Ar\4  
for(int i=1;;i++) aiea&aJ  
{ zf#V89!]C"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !DD|dVA{  
//Utility.log(in.readLine()); )t0t*xu#  
sHeader=httpConnection.getHeaderFieldKey(i); jRzR`>5  
if(sHeader!=null) eo"6 \3z  
{ l1a=r:WhH  
if(sHeader.equals("Content-Length")) .hnGHX  
{ 8\/E/o3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); JQ!D8Ut  
break; bc%7-%  
} Bx2E9/S3  
} Q']:k}y  
else \3Ys8umKq  
break; |0BmEF  
} ,0;E_i7  
} (',G Ako  
catch(IOException e){e.printStackTrace ();} ;DBO  
catch(Exception e){e.printStackTrace ();} BHqJ~2&FDW  
b>?X8)f2e  

WnU"&XZ  
Utility.log(nFileLength); 76(&O  
G ?H`9*y  
OP{ d(~+  
return nFileLength; -&y{8<bu4H  
} Xfk&{zO-j  
gtJUQu p2  
&H`yDrg6U  
//保存下载信息（文件指针位置） 4, 8gf2  
private void write_nPos() mbU[fHyV  
{ &$|k<{j[<f  
try{ Cj,fP[p#7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); O]90F  
output.writeInt(nStartPos.length); USfOc  
for(int i=0;i<nStartPos.length;i++) ~\(U&2t  
{ r)q6^|~47  
// output.writeLong(nPos); j'I$F1>Te  
output.writeLong(fileSplitterFetch.nStartPos); Xb5n;=)  
output.writeLong(fileSplitterFetch.nEndPos); h{VCx#!]  
} bo`w(h_  
output.close(); ZoF\1C ^  
} ^3F[^#"  
catch(IOException e){e.printStackTrace ();} 8tY],  
catch(Exception e){e.printStackTrace ();} rer=o S  
} 77.5 _  
y;3vr1?  
S2w|\"  
//读取保存的下载信息（文件指针位置） `dx+Qp  
private void read_nPos() ts aD5B  
{ 4L(axjMYU  
try{ Cir==7A0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 48Z{wV,  
int nCount = input.readInt(); W1i
Kn  
nStartPos = new long[nCount]; s+$l.aIO!  
nEndPos = new long[nCount]; %Hp
TQ   
for(int i=0;i<nStartPos.length;i++) *4dA(N\k"  
{ p(:\)HP)R  
nStartPos = input.readLong(); ;spuBA)[X  
nEndPos = input.readLong(); n
(0O'nS^  
} 5a&[NN  
input.close(); fYl$$.  
} A!x_R {,yH  
catch(IOException e){e.printStackTrace ();} pg;agtI  
catch(Exception e){e.printStackTrace ();} ehoDW
O]S  
} TY],H=  
w%g@X6  
bo4 :|Z  
private void processErrorCode(int nErrorCode) W -8<sv$b  
{ {;=I69X  
System.err.println("Error Code : " + nErrorCode); uL1e
?  
} =(3Qbb1i  
l%oie1g l  
r*OSEzGUz  
//停止文件下载 y9?BvPp+  
public void siteStop() u yzc"di  
{ 7AX<>^  
bStop = true; ;lB%N t<,  
for(int i=0;i<nStartPos.length;i++) t:9}~
%~  
fileSplitterFetch.splitterStop(); 4t|ril``]  
P*BA  
r=~yUT  
} x;?4AJ{  
} D\jRF-z  
//负责部分文件的抓取 =hH>]$J[  
**FileSplitterFetch.java k9vr6We'  
*/ I QS|  
package NetFox; E;fYL]j/oZ  
bW7tJ  
{+0]diD  
import java.io.*; ?kI-o0@O.  
import java.net.*; @TdPeTw\  
N4}j,{#  
. Zrt/;  
public class FileSplitterFetch extends Thread { dP=1*  
_>9|"seR  
- /]ro8V$  
String sURL; //File URL be|k"s|6)  
long nStartPos; //File Snippet Start Position nw+L _b  
long nEndPos; //File Snippet End Position $6Lgaz  
int nThreadID; //Thread's ID |CexP^;!U  
boolean bDownOver = false; //Downing is over 47ppyh6@  
boolean bStop = false; //Stop identical hWfJh0I
 
FileAccessI fileAccessI = null; //File Access interface mqrP0/sN  
Q.*qU,4);  
f<= #WV  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException G|Yw a=  
{ q.yS j  
this.sURL = sURL; Oz#
$x  
this.nStartPos = nStart; 3;zJ\a.+  
this.nEndPos = nEnd; Og4 X3QG  
nThreadID = id; 9OuK}Ssf  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 KJo[!|.  
} AU)"L_ i}  
~}q"M[{  
N)K};yMf  
public void run() >Vy=5)/i  
{ o3P`y:&  
while(nStartPos < nEndPos && !bStop) QrDzfe[  
{ :DXkAb2  
+AhR7R!
 
O8(;=exA  
try{ I\&..e0l  
URL url = new URL(sURL); q(M[ij  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .h~M&d!  
httpConnection.setRequestProperty("User-Agent","NetFox"); qAUqlSP5  
String sProperty = "bytes="+nStartPos+"-"; P%z\^\p"5  
httpConnection.setRequestProperty("RANGE",sProperty); T^B&GgW  
Utility.log(sProperty); p+SFeUp  
}L^Yoq]  
IsxPm9P2<  
InputStream input = httpConnection.getInputStream(); (cAv :EKpo  
//logResponseHead(httpConnection); +Pd&Yf
U9  
j#S>8: G  
,UopGlA ,  
byte[] b = new byte[1024]; a,b;H(em  
int nRead; i[`nu#n/  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Q6@}t&k4C  
{ y44FejH(v  
nStartPos += fileAccessI.write(b,0,nRead); RIJ+]uir4  
//if(nThreadID == 1) $v#Q'?jE  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); sesr`,m.,  
} :~3sW< PR  
I&l1b>  
W
p/!;  
Utility.log("Thread " + nThreadID + " is over!"); *[*LtyCQt4  
bDownOver = true; R/R[r> 1)6  
//nPos = fileAccessI.write (b,0,nRead); \[Op:^S  
} Vy.A`Hz  
catch(Exception e){e.printStackTrace ();} gV1&b (h  
} 4-^
|e  
} ;2q;RT`h  
M p:c.  
M8
X*fYn  
//打印回应的头信息 /tM<ois*  
public void logResponseHead(HttpURLConnection con) K++pH~o  
{ $,otW2:)  
for(int i=1;;i++) t_6sDr'.  
{ EGO;g^,  
String header=con.getHeaderFieldKey(i); )_"Cz".|9  
if(header!=null) ;X<#y2`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 7Oe |:Z  
Utility.log(header+" : "+con.getHeaderField(header)); w~y+Pv@   
else rVowH
P  
break; 4j|]=58  
} fIN8::Cs[  
} >gM|:FG  
V|zz
j[c  
I gcVl/d  
public void splitterStop() IE.JIi^w  
{ b)9bYkd  
bStop = true; wUHuykF  
}  Z+`mla  
S!A)kK+  
Zy,
U'Dv  
} $j0]+vT  
QFU;\H/  
m:5*:Ii.  
/* o[q Kf  
**FileAccess.java #qWa[k
B  
*//文件访问(定位，写)  /s.sW l  
package NetFox; ftq&<8  
import java.io.*; y;<^[  
nF0$  
&1YAPxX  
public class FileAccessI implements Serializable{ A]`63@-.  
lTW5
>%  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 >e :&kp  
RandomAccessFile oSavedFile; |B<+Y<)f^  
long nPos; VJ;n0*/  
*X8<hYKZq  
vT"T*FKh:  
public FileAccessI() throws IOException J@C8;]  
{ |VbF&*v`  
this("",0); #X'!wr|-  
} P0uUVU=B|  
8`XpcK-0  
L^3~gZ  
public FileAccessI(String sName,long nPos) throws IOException ,u7:l  
{ %myg67u  
oSavedFile = new RandomAccessFile(sName,"rw"); x9XQ  
this.nPos = nPos;
u'M\m7  
oSavedFile.seek(nPos); |K| c  
} s<Pk[7`*  
]n1@!qa48  
^dFdw\  
public synchronized int write(byte[] b,int nStart,int nLen) ag^EH"%zw  
{ r7o63]  
int n = -1; G/>upnA{w  
try{ 5VdF^.:u  
oSavedFile.write(b,nStart,nLen); :\9E%/aAD  
n = nLen; sYM3&ikyHI  
} iIji[>qz  
catch(IOException e) Tn,'*D@l  
{ XBe!9/'k>  
e.printStackTrace (); W}#eQ|oCV  
} }D/0&<1  
+
+D-,>.  
K.4t*-<`[  
return n; JYA$_T
  
} RhIRCN9  
zC#[  
^55#!/9  
} Jj4!O3\I  
+#7e?B  
W- 5Z"m1I  
/* pE<dK.v6  
**SiteInfoBean.java pe$" nUy|  
*/ \)'s6>58|  
package NetFox; ts/rV#s~  
FB-?{78~  
jPU:&1(_ n  
public class SiteInfoBean { iV;X``S  
u^T)4~(  
&QFg=  
private String sSiteURL; //Site's URL bzD <6Z  
private String sFilePath; //Saved File's Path hi4#8W
 
private String sFileName; //Saved File's Name DjUif "v  
private int nSplitter; //Count of Splited Downloading File d6,SZ*AE  
.E}fk,hLB  
k44sV.G4L  
public SiteInfoBean() L;$Gn
"7~  
{//nSplitter的缺省值为5 xR `4<  
//default value of nSplitter is 5 $}RBK'cr}  
this("","","",5); gBb+Q,  
} 3*C9;Q}  
|pxM8g1w  
qE?*:$  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) %_C!3kKv~  
{ 6&/n/g  
sSiteURL= sURL; Jk=E"I6  
sFilePath = sPath; 6qg_&woJ3  
sFileName = sName; 0.C[/u[  
this.nSplitter = nSpiltter; dnt: U!TW@  
w:%3]2c  
`%_yRJd|;  
} e<o{3*%p)  
OhMnG@@  
'&?cW#J?  
public String getSSiteURL() wh8h1I  
{ ZdG?fWWA  
return sSiteURL; t@(S=i7}-  
} 3>;zk#b2  
MQ7d IUs  
bso l>M[<  
public void setSSiteURL(String value) 'Vq_/g!?1  
{ M ^gva?{  
sSiteURL = value; <Vucr   
}  JwEQR  
@%Y$@Qb{  
}jTCzqHW]  
public String getSFilePath() uFPJ}m[>5  
{ yneIY-g(p  
return sFilePath; T=Q"|S]V  
} Mg3>/!  
2;X{ZLo
 
eT8(O36%  
public void setSFilePath(String value) &("HH"!  
{ D >ax<t1K  
sFilePath = value; Hw[(v[v  
} 1N8gH&oF
 
TY,5]*86I&  
/4x3dwXW@  
public String getSFileName() > Q[L,I  
{ $M%<i~VXe&  
return sFileName; W~(4t:hp  
} T^FeahA7;  
peW4J<,  
>a;0<Ui&Q  
public void setSFileName(String value) ;Z:zL^rvn  
{ M.B
0)  
sFileName = value; '?7?
"v  
} rjsqXo:9  
8K(3{\J[V  
7i(U?\A;.  
public int getNSplitter() EVs.'Xg<  
{ v&}+ps_W  
return nSplitter; ,au-g)IFZ  
} 7nr+X Os  
c*F'x-TH  
6,Aj5jG  
public void setNSplitter(int nCount) :)7{$OR&  
{ up`.#GWm  
nSplitter = nCount; DVNx\t  
} jm~(OLg  
} dC&{zNG  
)0F\[Jl}  
q]PeS~PjF\  
/* X{2))t%  
**Utility.java r(qAe{  
*/ d3%1P)  
package NetFox; E1'| ;}/  
k)l*L1Y4:  
)1de<# qM  
public class Utility { $:&?
!>H  
2@!Ou$W  
6k14xPj  
public Utility() {|cuu"j26  
{ xOfZ9@VU  
IC5[:UZ5]
 
9hoTxWpmy  
} ?[Gj?D.Wc  
r
uqx#]-  
//线程睡眠 8&d
s  
public static void sleep(int nSecond) r7dvj#^  
{ +[W_Jz  
try{ f+A!w8E  
Thread.sleep(nSecond); rID_^g_tP8  
} vpTYfE  
catch(Exception e) 4(2iR0N  
{ a-nf5w>&q  
e.printStackTrace ();
2
4)Sf  
} |n9q4*dN  
} /m>%=_nz  
!\e&7sV~Q  
//日志 \gtI4zl*J  
public static void log(String sMsg) E]Wnl\Be  
{ J})#43P  
System.err.println(sMsg); kd0~@rPL  
} b \pjjb[  
4i<V^go"  
BNA`Cc1VV  
public static void log(int sMsg) YGAB2`!U  
{ /K+GM8rtE  
System.err.println(sMsg); L p(6K  
} }Z^r<-N  
} 4[q'1N6-  
^Ob#B!=  
W PDL$y  
/* *^h$%<QI  
**TestMethod.java D I` M  
*/ .)eJL  
package NetFox; .nGYx  
ry99R|/d1  
pUTC~|j%:  
public class TestMethod { V%kZ-P*  
zxo0:dyw7  
A'jw;{8NpF  
public TestMethod() kqyVUfX$3  
{ ///xx/weblogic60b2_win.exe )Fa

6'M  
try{ C3m](%?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >9?BJv2  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); u<}PcI.  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ux8:  
fileFetch.start(); HTpoYxn(  
} ^M51@sXI7  
catch(Exception e){e.printStackTrace ();} I $5*Puy#  
IUK!b2!`  
+y}4^3Vx^  
} `#v(MK{9+V  
C`)n\?:Sth  
!21#NCw  
public static void main(String[] args) {9 PeBc  
{ gy%/zb
Zx  
new TestMethod(); T(n<@Ac]V  
} x37pj)i/  
} Py}`k1t*f  
点击下载更多相关资料