http断点续传简单实现（java)

/* $'I-z.GV  
**SiteFileFetch.java N4L#$\M  
*/ =sIkA)"!=  
package NetFox; .%x1%TN  
import java.io.*; 8Ry%HV9VE  
import java.net.*; l(B(gPvU  
(X{o =co,  
o`{@':%D`  
public class SiteFileFetch extends Thread { %fF0<c^-U  
CGp7 Tx#  
H,Y+n)5  
SiteInfoBean siteInfoBean = null; //文件信息Bean X+$IaLfCxD  
long[] nStartPos; //开始位置 ^U8^P]{R|  
long[] nEndPos; //结束位置 d#W>"Cqxqa  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ==ZL0 ][  
long nFileLength; //文件长度 p~evPTHnrX  
boolean bFirst = true; //是否第一次取文件 &BZjQK  
boolean bStop = false; //停止标志 ->u}b?aF  
File tmpFile; //文件下载的临时信息 zHg1K,t:  
DataOutputStream output; //输出到文件的输出流 G.B~n>}JU,  
"C~Zl&3  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） b"PRa|]  
public SiteFileFetch(SiteInfoBean bean) throws IOException |z 8Wh  
{ 7jzd I!  
siteInfoBean = bean; a0
/[L  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9e _8Z@|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ETMF.-P  
if(tmpFile.exists ()) 1Y6DzWI  
{ vFx0B?  
bFirst = false; ej;\a:JL  
read_nPos(); <fm<UO,%  
} ZDl6F`  
else wj$WE3Y  
{ |.~0Ulk,  
nStartPos = new long[bean.getNSplitter()]; gc[BP>tl\  
nEndPos = new long[bean.getNSplitter()]; H\^zp5/  
} qHf8z;lc  
C_rA'Hy  

%-Oo92tP  
n%&+yg  
} sqE? U*8.-  
t \;,$i  
~}@cSv'(1  
public void run() .?NraydwV  
{ tvEf-z  
//获得文件长度 YacLYo#  
//分割文件 KwxO%/-}S  
//实例FileSplitterFetch Ra-%,cS  
//启动FileSplitterFetch线程 |<Rf^"T  
//等待子线程返回 c-".VF  
try{ _I<LB0kgf.  
if(bFirst) 5LVzT1j|  
{ o"Mhwh  
nFileLength = getFileSize(); ^E}};CsT  
if(nFileLength == -1) 4cQ|"sOzD  
{ aS)Gj?Odf  
System.err.println("File Length is not known!"); d'UCPg<Y  
} 2)^gd  
else if(nFileLength == -2) sF!nSr  
{ TChKm-x  
System.err.println("File is not access!"); f~-Ipq;F  
} & G8tb>q<V  
else N~0~1 WQn  
{ 4PDxmH]y  
for(int i=0;i<nStartPos.length;i++) $9PscubM4  
{ %DIZgPd\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); W,-fnJk  
} :+Okv$v4  
for(int i=0;i<nEndPos.length-1;i++) Pp~:e}  
{ Puodsd  
nEndPos = nStartPos[i+1]; @q<F_'7is  
} p0bMgP  
nEndPos[nEndPos.length-1] = nFileLength; Ow f:Kife  
} s!eB8lkcT  
} ")i>-1_H  
 b
MDj+i  
FAbl
5VW'  
//启动子线程 Unc_e  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; }Gi4`Es  
for(int i=0;i<nStartPos.length;i++) Di>
B:=  
{ vd]75  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), C'oNGOEd  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), V0)F/qY  
nStartPos,nEndPos,i); +L
>?kr[i[  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }n[<$*W^  
fileSplitterFetch.start(); Qs1e0LwA9  
} &* 1iW(x  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f.Feo  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,d~6LXr<fM  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", b@?pofZ`k  
nEndPos = " + nFileLength); {- Y.C
*E  
// fileSplitterFetch[nPos.length-1].start(); p0Ra`*f  
9}*<8%PSt,  
@teNT"  
//等待子线程结束 8sz|9~  
//int count = 0; +#=l{_Z,ZJ  
//是否结束while循环 +x_9IvaW&?  
boolean breakWhile = false; nQ}$jOU&  
u{d\3-]/  
Y}UVC|Ef  
while(!bStop) qG?svt  
{ nr>Os@\BU  
write_nPos(); ne-;gTP;  
Utility.sleep(500); f\]spl
L  
breakWhile = true; 2SHS!6
:Rl  
R[T94U  
at5>h   
for(int i=0;i<nStartPos.length;i++) [44C`x[8M+  
{ g+  P  
if(!fileSplitterFetch.bDownOver) 3wf&,4`EX  
{ iwS55o  
breakWhile = false; ~4'AnoD1w  
break; j
|X>:!4r  
} QnN cGH  
} b<1+q{0r  
if(breakWhile) d@aPhzLu  
break; ~]LkQQ'  
N`1W"Rx!  
:,[=g$CT:  
//count++; {Xw6p  
//if(count>4) 'vc>uY  
// siteStop(); rmh 1.W  
} 2(5<Wj"  
i?0+f}5<p  
`%oJa`  
System.err.println("文件下载结束！"); e|2@z-Sp-  
} v"3($?au0  
catch(Exception e){e.printStackTrace ();} guc[du  
} j,@@[{tu  
]sL)[o  
bxR6@  
//获得文件长度 ^Pp2T  
public long getFileSize() Z?"f#  
{
<A+n[h  
int nFileLength = -1; Fx6]x$3  
try{ SNl% ?j| f  
URL url = new URL(siteInfoBean.getSSiteURL()); fqp!^-!X  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); pN?geF~t|  
httpConnection.setRequestProperty("User-Agent","NetFox"); !${7)=|=1  
XMpa87\  
o +KDK{MD  
int responseCode=httpConnection.getResponseCode(); t'{IE!_  
if(responseCode>=400) RF$2p4=[  
{ Z\. n6  
processErrorCode(responseCode); Nt'6Y;m!  
return -2; //-2 represent access is error &Ay[mZQ 7  
} jqv"8S5  
*3Qwmom  

R.'-jvO  
String sHeader; ;%W]b  
R;l;;dC
=  
m]Gxep0%  
for(int i=1;;i++) F)n^pT  
{ ::`#qa4!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); J<;@RK,c_  
//Utility.log(in.readLine()); 0s'h2={iI  
sHeader=httpConnection.getHeaderFieldKey(i); l2Pry'3  
if(sHeader!=null) s:ZYiZ-  
{ d.3cd40Q  
if(sHeader.equals("Content-Length")) T j(MIFi|5  
{ o7i>D6^^  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); hteAuz4H  
break; d
YxX%"J  
} I6-.;)McO  
} s{9G//  
else =IH~:D\&  
break; BL[N  
} c$P68$FB  
} Cno+rmsfT  
catch(IOException e){e.printStackTrace ();} [L ?^+p>  
catch(Exception e){e.printStackTrace ();} j/p1/sJ[y  
J5Ovj,[EZ  
{3`cSm6c  
Utility.log(nFileLength); slTE.  
Mj<T+Ohz  
/nWBol,  
return nFileLength; ?RQ_LA;  
} hZ`<ID  
H ]z83:Z  
5_7y1  
//保存下载信息（文件指针位置） J~.`  
private void write_nPos() iu.v8I;<  
{ \)`OEGdOR\  
try{ K;Fs5|gFU  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6m%#cP (6K  
output.writeInt(nStartPos.length); CuT50N;tk  
for(int i=0;i<nStartPos.length;i++) x:$ xtu  
{ l=PZlH y1G  
// output.writeLong(nPos); [nASMKK0  
output.writeLong(fileSplitterFetch.nStartPos); 6^e}^~|  
output.writeLong(fileSplitterFetch.nEndPos); 363KU@`  
} XY^]nm-{I  
output.close(); ^).  
} P
C!g?6J  
catch(IOException e){e.printStackTrace ();} vzFo"  
catch(Exception e){e.printStackTrace ();} 2h:{6Gq8  
} Tx>V$+al
 
92x)Pc^D  
s[bQO1g;*  
//读取保存的下载信息（文件指针位置） ,GF]+nI89  
private void read_nPos() +L|x^B3  
{ E?- ~*T
 
try{ H~ E<ek'~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Ozg,6&3ji  
int nCount = input.readInt(); q ;"/i*+3  
nStartPos = new long[nCount]; _9C,N2a{C  
nEndPos = new long[nCount]; v\o m  
for(int i=0;i<nStartPos.length;i++) s}F.D^^G  
{ />n!2'!  
nStartPos = input.readLong(); MY}/h@  
nEndPos = input.readLong(); ;,/4Ry22j-  
} goe%'k,  
input.close(); -}u1ZEND  
} 4sq](!A  
catch(IOException e){e.printStackTrace ();} )FN\jo!!.  
catch(Exception e){e.printStackTrace ();} iNr&;  
} Z!-V&H.
 
[,3E#+y  
V|G*9^Y  
private void processErrorCode(int nErrorCode) lAR1gHhJ  
{ 22'Ra[  
System.err.println("Error Code : " + nErrorCode); I? ="Er[g}  
} `S+n,,l  
2@W`OW Njm  
RzU
9]e  
//停止文件下载 Ma4eu8  
public void siteStop() ^5Zka!'X2Z  
{ K~4b
T=   
bStop = true; Y-lwS-Ii  
for(int i=0;i<nStartPos.length;i++) 85
e*um^  
fileSplitterFetch.splitterStop(); W_6gV  
7K ~)7U  
}@"v7X $  
} *R}p9;dpO  
} W[R`],x`  
//负责部分文件的抓取 G5%k.IRz  
**FileSplitterFetch.java r KYQ 8T  
*/ #"8'y  
package NetFox; <Sr:pm  
&c}2[=  
LP !d|X  
import java.io.*; YC$>D?FW  
import java.net.*; fw VI%0C@  
;66{S'*[  
BNe>Lko  
public class FileSplitterFetch extends Thread { e
,Z[Nox  
Qsw
.429t  
hYh~%^0dt  
String sURL; //File URL Khl0~  
long nStartPos; //File Snippet Start Position &*bpEdkZ  
long nEndPos; //File Snippet End Position 65nK1W`i  
int nThreadID; //Thread's ID ~!M"  
boolean bDownOver = false; //Downing is over Ls+vWfF=#  
boolean bStop = false; //Stop identical ]
"^p}:  
FileAccessI fileAccessI = null; //File Access interface 8 &v)Vi-  
2a;[2':  
~T/tk?:8Vi  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException YI;MS:Qj  
{ ;VEKrVD  
this.sURL = sURL; =f23lA  
this.nStartPos = nStart; x0%yz+i{:  
this.nEndPos = nEnd; |tU wlc>  
nThreadID = id; kkW}:dBl  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _0ZU I^#  
} }#2(WHf=<  
UkXa mGoy3  
;U$Rd,T4S  
public void run() y2mSPLw  
{ jtq^((Ux  
while(nStartPos < nEndPos && !bStop) J qmL|
S)  
{ wCV~9JTJ!  
Jl6lZd(Np  
L4ct2|w}ul  
try{  -PU.Uw]  
URL url = new URL(sURL); +md"X@k5*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); rVRv*W  
httpConnection.setRequestProperty("User-Agent","NetFox"); R,BINp  
String sProperty = "bytes="+nStartPos+"-"; m
s\\R@R  
httpConnection.setRequestProperty("RANGE",sProperty); IxG7eX!  
Utility.log(sProperty); ^N7 C/" p  
g_!xD;0  
)=bW\=[8  
InputStream input = httpConnection.getInputStream(); ~w9`l8/0  
//logResponseHead(httpConnection); xn@oNKD0  
6__HqBQ  
/1D.Ud^  
byte[] b = new byte[1024]; UR S=1+  
int nRead; =;F7h @:  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Rlm28  
{ NxDVU?@p*  
nStartPos += fileAccessI.write(b,0,nRead); Ct zWdo.  
//if(nThreadID == 1) +\u\BJ!LAJ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P2 qC[1hYH  
} a#x@e?GvI  
F-M)6&T  
5R%y3::$S  
Utility.log("Thread " + nThreadID + " is over!"); 1C]BaPbL  
bDownOver = true; (_+ux1h6^  
//nPos = fileAccessI.write (b,0,nRead); `B:hXeI  
} ^<uQ9p^B  
catch(Exception e){e.printStackTrace ();} vA[7i*D{w  
} HD1/1?y!@q  
} y+V>,W)r7  
(<@`MPI\@  
(ip3{d{CT]  
//打印回应的头信息 jGo\_O<of  
public void logResponseHead(HttpURLConnection con) G )`gn  
{ >6@,L+-6r  
for(int i=1;;i++) Ts|;5ya5m  
{ `*`ZgTV  
String header=con.getHeaderFieldKey(i); &&m1_K  
if(header!=null) {x[C\vZsi]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); q_L. Sy|)  
Utility.log(header+" : "+con.getHeaderField(header)); y\[* mgl:  
else tA'5ufj*:  
break; ?YDMl  
} }
W[=O:p  
} KoWG:~>|  
2R^Eea  
.3@Pz]\M#>  
public void splitterStop() rY1jC\  
{ ='C;^ Bk  
bStop = true; ^gNbcWc7CU  
} $fT#Wva-\d  
@+)T"5_Y[  
<]|!quY<*  
} tK'9%yA\  
Ol>/^3a=  

o]&P0 b  
/* ^P A|RFP  
**FileAccess.java `0w!&  
*//文件访问(定位，写) FFmXT/K"/j  
package NetFox; "A5z!6T{  
import java.io.*; 5~(nHCf>  
#e[r0f?U  
9>vB,8  
public class FileAccessI implements Serializable{ /^I!)|At  
bxBndxl  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 F[F NtZ  
RandomAccessFile oSavedFile; 8493O x4 O  
long nPos; >?G!>kw  
kE!ky\E  
huR ^l  
public FileAccessI() throws IOException xgM\6e  
{ w vI v+Q9  
this("",0); ]gF=I5jn]  
} Tn(uH17  
9(_n8br1  
/oGaA@#+  
public FileAccessI(String sName,long nPos) throws IOException 6x/o j`_[  
{ v;}MHl  
oSavedFile = new RandomAccessFile(sName,"rw"); +UTBiB R  
this.nPos = nPos; eu$"GbqY  
oSavedFile.seek(nPos); Nd@/U c  
} {!wd5C@  
=KD[#au6a  
4$ah~E>,t  
public synchronized int write(byte[] b,int nStart,int nLen) 0Jd>V  
{ R mo'3  
int n = -1; d>r]xXB6  
try{ Eq=JmO'gHs  
oSavedFile.write(b,nStart,nLen); p!<PRms@  
n = nLen; 8vfC  
} c]qh)F$s8  
catch(IOException e) o4L
VG  
{ C{G%"q  
e.printStackTrace (); ?#nk}=;g8  
} rg]z  
*<?KOM  
-b?s\X  
return n; N f}ZG  
} NpbZt;%t  
Wkr31Du\K  
`}a-prT<f  
} %;Z_`W  
E%Ko[G  
\`-xxhb?e  
/* BgB0  
**SiteInfoBean.java 3u s^\w#  
*/ %/_E8GE  
package NetFox; @B?'Mu*  
^$rqyWZYp  
O>" |5wj  
public class SiteInfoBean { e#WASHZN  
p`!<yq2_  
@f,/K1
k  
private String sSiteURL; //Site's URL F&lSRL+v  
private String sFilePath; //Saved File's Path 5 (q4o`  
private String sFileName; //Saved File's Name tCu.
Fc@  
private int nSplitter; //Count of Splited Downloading File azRp4~2?  
<^ratz!-  
a,n#E!zT?w  
public SiteInfoBean() 5)->.*G*  
{//nSplitter的缺省值为5 uE..1N&*  
//default value of nSplitter is 5 f/m0,EERk  
this("","","",5); RS2uk7MB  
} \(zUI  
I-Am9\  
_!?a9  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) S&Hgr_/}c  
{ ],'"iVh  
sSiteURL= sURL; {Z>Mnw"R  
sFilePath = sPath; %P C[-(Q  
sFileName = sName; ~;t/VsgGW  
this.nSplitter = nSpiltter; ]v+yeGIKS  
Ak3V< =gx  
w5t|C>  
} UH((d*HX4  
e=_Ng j)  
Y+0GJuBf  
public String getSSiteURL() s;[WN.  
{ :8]y*j  
return sSiteURL; ?0:=+%.  
} =yPV9#(I/  
XXXQAY-,C  
Sh:_YD^(  
public void setSSiteURL(String value) ^bLFY9hSC  
{ (yB]$  
sSiteURL = value; =i},$"Bf*%  
}  LYyud  
e^N}(Kpy  
F><ficT  
public String getSFilePath() ^3QJv{)Q  
{ yIWgC[  
return sFilePath; k/)h@K8@  
} 8KsP
AK_  
ss`Sl$  
Q9&H/]"v  
public void setSFilePath(String value) '*<I<? z;  
{ /*t H$\6*  
sFilePath = value; Y<_;8%S  
} O.jCDAP  
1R7tnR@[u  
!%N@>[  
public String getSFileName() RSnBG"  
{ 3`Xzp  
return sFileName; ryb81.|  
} !1Ht{cA0  
Q^X}7Z|T  
7"OJ,Mx%  
public void setSFileName(String value) Zh`[A9I/  
{ dk0} q6~
 
sFileName = value; 2q*wYuc  
} F 1l8jB\  
D&qJ@PR  
h05<1>?|  
public int getNSplitter() ]Qe"S>,?`  
{ ^z51f>C  
return nSplitter; *&hbfsP:  
} e$&n)>%  
r;+a%?P  
LCuz_LTFq{  
public void setNSplitter(int nCount) ?%n"{k?#  
{ yq[@Cw  
nSplitter = nCount; -lR7 @S  
} |7${E^u  
} gMp' S  
|
/n  
qqys`.  
/* Mq_P'/  
**Utility.java T1'\!6_5  
*/ 9TwKd0AT$&  
package NetFox; Q 9E.AN  
Z;njSw%:  
9!.S9[[N  
public class Utility { unKgOvtj  
>]uu?!PU  
-F
JLM  
public Utility() mA@!t>=oMq  
{ /!qP=ngw9  
'8(UiB5d  
h\Q@zR*0a  
} y>)c?9X  
{WQ6=wGpS  
//线程睡眠 (H\ `/%Bp  
public static void sleep(int nSecond) -!K&\
hEjj  
{ T|0d2aa  
try{ 1U?5/Ja  
Thread.sleep(nSecond); >8b%*f8R  
} 1g jGaC  
catch(Exception e) c _!!DEe7  
{ #on ,;QN  
e.printStackTrace (); TKgN31`  
} *z.rOY= 8  
} IW-|"5?9'  
SpYmgL?wJ  
//日志 9hh~u -8L  
public static void log(String sMsg) xLfv:Rp  
{ b=U3&CV9  
System.err.println(sMsg); /Gn0|]KI  
} tGzp=PyA  
RD=V`l{Z  
CGkx_E]  
public static void log(int sMsg) c((bUjS'=Y  
{ U<E]c 4*  
System.err.println(sMsg); 67 ~pn  
} f1;@a>X  
} uGm?e]7Hx<  
0s\ -iub=d  
M'F<1(  
/* /+8VW;4|I  
**TestMethod.java YD0hDp  
*/ fre5{=@  
package NetFox; +\)Y,@cw  
+r9neS.l  
=\oL'>q  
public class TestMethod { E!BzE_|i  
L]u^$=rI  
)Y9\>Xj7  
public TestMethod() ;(A-  
{ ///xx/weblogic60b2_win.exe )!caOGvhJ  
try{ O0s!3hKu  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); t`R{N1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); xplV
6q`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); u6Wan*I?  
fileFetch.start(); MLg{Y?@  
} K+XUC  
catch(Exception e){e.printStackTrace ();} C'R6mz%Q?  
SynRi/BRmw  
3D1y^I  
} }p?67y/  
3vjOfr`  
(DS"*4ty  
public static void main(String[] args) *?]<=IV?  
{ nc\2A>f`  
new TestMethod(); BG= J8  
} k_ywwkG9lU  
} ';My"/ Z-  
点击下载更多相关资料