http断点续传简单实现（java)

/* xD1wHp!+  
**SiteFileFetch.java LoCxoAg  
*/ n,HWVo>([  
package NetFox; ~{NDtB)  
import java.io.*; UT{Nly8u  
import java.net.*; pwZ &2&|  
`HJwwKd  
A1'IK.  
public class SiteFileFetch extends Thread { 'M'LJ.,"/  
I" j7  
A,=l9hE'  
SiteInfoBean siteInfoBean = null; //文件信息Bean wK\SeX  
long[] nStartPos; //开始位置 3
QR-8  
long[] nEndPos; //结束位置 >XZq=q]E!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 5N|77AAxK  
long nFileLength; //文件长度 ]B7t9l  
boolean bFirst = true; //是否第一次取文件 F H%yyT  
boolean bStop = false; //停止标志 %##9.Xm6l  
File tmpFile; //文件下载的临时信息 1^W Aps  
DataOutputStream output; //输出到文件的输出流 Bkz   
JGdBpj:  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 9a4RW}S<  
public SiteFileFetch(SiteInfoBean bean) throws IOException ;zJ_apZ:{  
{ %vThbP#mR|  
siteInfoBean = bean; ix/uV)]k`  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ftH 0aI  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); CNN?8/u!@  
if(tmpFile.exists ()) kU^@R<Fo  
{ :iWV:0)P  
bFirst = false; hOC,Eo  
read_nPos(); vcSS+  
} >qgBu_  
else 2 rBF<z7  
{ #F6ak,9S4  
nStartPos = new long[bean.getNSplitter()]; cM"I3  
nEndPos = new long[bean.getNSplitter()]; oz0-'_  
} :m~lgb<  
~g,QwaA[  
_j2`#|oG  
@v'<~9vG  
} %FRkvqV*  
dW5z0VuB$/  
~G$OY9UC  
public void run() SwL\=nq+~  
{ E
Xi+
pm  
//获得文件长度 q_K1L  
//分割文件 2>r.[
  
//实例FileSplitterFetch _HL3XT  
//启动FileSplitterFetch线程 [&4y@  
//等待子线程返回 tw(2V$J  
try{ 7xcYM  
if(bFirst) qqAsh]Z  
{ !3&}r  
nFileLength = getFileSize(); />oU}m"k  
if(nFileLength == -1) }B.C#Y$@  
{ j)0R*_-B[  
System.err.println("File Length is not known!"); Nl8Cctrf  
} 4NzHzn  
else if(nFileLength == -2) t.TQ@c+,J  
{ oe<Y,%u"6
 
System.err.println("File is not access!"); hh{liS% 10  
} d"cfSH;h  
else WT)")0)[  
{ >fdN`W}M  
for(int i=0;i<nStartPos.length;i++) O*PHo_&G  
{ ) jvkwC  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); RAxz+1JT  
} &sWyh[`P  
for(int i=0;i<nEndPos.length-1;i++) s [!SG`&  
{ j AE0$u~.  
nEndPos = nStartPos[i+1]; ,jWd?-NH  
} X>4`{x`  
nEndPos[nEndPos.length-1] = nFileLength; 9..k/cH  
} a]k&$  
} {3Rax5Ty  
^/uGcz|.  
Rb0{t[IU  
//启动子线程 {MtB!x  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; O o:jP6r  
for(int i=0;i<nStartPos.length;i++) ?x0yiV~dL  
{ *LVM}| f  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "10VN*)J}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), cmeyCyV*  
nStartPos,nEndPos,i); aFym&n\  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ..:V3]-D  
fileSplitterFetch.start(); S#9SAX [  
} [:'n+D=T3M  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), C"{on%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); (D{}1sZBQ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #.)>geLC>9  
nEndPos = " + nFileLength); l.juys8s  
// fileSplitterFetch[nPos.length-1].start(); 85 hYYB0v  
jJvNN -^  
r;C\eN  
//等待子线程结束 x
(`$D  
//int count = 0; bM-Rj1#Lo  
//是否结束while循环 :I('xVNPz  
boolean breakWhile = false; /z5lxS@#  
#V6 -*  
m5pVt4  
while(!bStop) w-$w  
{ k ))*z FV  
write_nPos(); ;`B35K  
Utility.sleep(500); * 2%e.d3"M  
breakWhile = true; Uz|]}t5V  
\7/_+)0}'  
G= cxc_9  
for(int i=0;i<nStartPos.length;i++) {1
%ZyY  
{ >B  
if(!fileSplitterFetch.bDownOver) v~Qy{dn P  
{ zTB9GrU  
breakWhile = false; E2|iAT+=.  
break; obq}#  
} M<unQ1+wh  
} O| ]Ped9  
if(breakWhile) W6T
&hB  
break; 5KR|pFq  
6hK"k  
DeA'D|  
//count++; e63|Z[8  
//if(count>4) o3qv945  
// siteStop(); D3xaR  
} CE,Om^  
sCQup
^\  
c5e\ckqm^  
System.err.println("文件下载结束！"); L@r.R_*H?s  
} sV[Z|$&Z  
catch(Exception e){e.printStackTrace ();} Xb*_LZAU  
} h\d($Ki  
M[u3]dN  
4d G-  
//获得文件长度 "S`wwl  
public long getFileSize() ZPao*2xz  
{ MPn>&28"|K  
int nFileLength = -1; |:+pPh!-  
try{ i(;-n_:,`  
URL url = new URL(siteInfoBean.getSSiteURL()); %n25Uq  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); r5!M;hU1j  
httpConnection.setRequestProperty("User-Agent","NetFox"); rVy\,#|  
*hs<Ez.cC  
p0y?GNQ  
int responseCode=httpConnection.getResponseCode(); SsX05>  
if(responseCode>=400) TSSt@xQ+  
{ {K4t8T]  
processErrorCode(responseCode); [E (M(w':  
return -2; //-2 represent access is error X-#mv|3  
} JK"uj%  
.oj"ru  
43=-pyp  
String sHeader; ?]D+H%3[$i  
y%bqeo L~  
Os 2YZ<t  
for(int i=1;;i++) \BaN5+
B6  
{ ',`4 U F  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); J7;n;Mx  
//Utility.log(in.readLine()); V C'-h~  
sHeader=httpConnection.getHeaderFieldKey(i); h
X| UE  
if(sHeader!=null) V)QR!4De  
{ |~LjH|*M  
if(sHeader.equals("Content-Length")) BC{J3<0bf@  
{ 5qQ(V)ah  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \Ntdl:fSw  
break; ]#q7}Sd  
} )^S^s>3  
} b[o"Uq@8?  
else _8pkejg  
break; s*/ G- lY  
} 36WzFq#  
} NvHy'
 
catch(IOException e){e.printStackTrace ();} sk6
|_  
catch(Exception e){e.printStackTrace ();} ,tF" 4|
#  
^%$W S,  
soQzIx  
Utility.log(nFileLength); nQ!#G(_nO  
IOZ|85u=  
:$Q]U2$mPS  
return nFileLength; OGi4m |  
} :'rZZeb'  
bA^:p3  

[-Tt11  
//保存下载信息（文件指针位置） %802H%+  
private void write_nPos() YZ:'8<  
{ h9w^7MbO  
try{ wQrPS  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?Gv!d  
output.writeInt(nStartPos.length); `)!2E6 =  
for(int i=0;i<nStartPos.length;i++) +6)kX4  
{ 2j/1@Z1j=  
// output.writeLong(nPos); &Yks,2:P  
output.writeLong(fileSplitterFetch.nStartPos); f.84=epv  
output.writeLong(fileSplitterFetch.nEndPos); xiOrk  
} qMdtJ(gq  
output.close(); xVz -_z  
} dms:i)L2  
catch(IOException e){e.printStackTrace ();} zV(tvt  
catch(Exception e){e.printStackTrace ();} i~Ob( YIH  
} 2N8sq(LK{  
^@LhUs>3  
V?V)&y] 4  
//读取保存的下载信息（文件指针位置） ~v(M6dz~vk  
private void read_nPos() 3g#=sd!0O@  
{ =']};  
try{ O{cGk: y  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); q{Ta?|x#  
int nCount = input.readInt(); F;&fx(  
nStartPos = new long[nCount]; 9k+&fyy  
nEndPos = new long[nCount]; (T#(A4:6S  
for(int i=0;i<nStartPos.length;i++) vl{_M*w ;  
{ m57tOX  
nStartPos = input.readLong(); S}p&\w H  
nEndPos = input.readLong(); yZ~eLWz  
} 
`_g?y)  
input.close(); J%-lw{FC  
} )>X|o$2  
catch(IOException e){e.printStackTrace ();} . I&)MZ>n  
catch(Exception e){e.printStackTrace ();} &~JfDe9IS  
} g*r{!:,t  
VRQbf  
B/9<b{6  
private void processErrorCode(int nErrorCode) IU'!?XVo  
{ N" Jtg@w  
System.err.println("Error Code : " + nErrorCode); iI@Gyq=  
} am'p^Z@  
`\4
JwiPo  
Wh'_slDH+  
//停止文件下载 7~l  
public void siteStop() ;aK !eD$  
{ u388Wj   
bStop = true; gQpD]p%k  
for(int i=0;i<nStartPos.length;i++) mA] 84zO  
fileSplitterFetch.splitterStop(); +?5Uy
*$  
hzuMTKH9  
oB{}-[G  
} "J[i=~(  
} : `6$/DK  
//负责部分文件的抓取 id#k!*$7  
**FileSplitterFetch.java G0;EbJ/&  
*/ WP@JrnxO\`  
package NetFox; <;,S"e  
Th;gps%b  
Z/6'kE{l  
import java.io.*; K'{W9~9Lq  
import java.net.*; LnI{S{]wDh  
g"dZB2`C  
\l=KWa3Q  
public class FileSplitterFetch extends Thread { Q1ABnacR  
}2BH_  2  
[>M*_1F  
String sURL; //File URL [,o5QH\Etq  
long nStartPos; //File Snippet Start Position mb~=Xyk&  
long nEndPos; //File Snippet End Position z^a!C#IX  
int nThreadID; //Thread's ID ),y!<\oQ  
boolean bDownOver = false; //Downing is over rm)SfT<  
boolean bStop = false; //Stop identical kTiPZZI  
FileAccessI fileAccessI = null; //File Access interface H6PXx  
rMXOwkE  
/!{A=N
  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +Sdx8 Z5  
{ vA

"`0  
this.sURL = sURL; #EQx
  
this.nStartPos = nStart; k}f<'g<H  
this.nEndPos = nEnd; VNxpOoV=S  
nThreadID = id; FG;<`4mY  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 B=Zukg1G  
} hV>4D&<  
@cS1w'=  
sx-Hw4.a"  
public void run() I"F .%re  
{ z"s%#/#  
while(nStartPos < nEndPos && !bStop) 7S dV%"  
{ vzohq1r5  
&` 00/p  
&8X .!r`f  
try{ n$OE~YwP{  
URL url = new URL(sURL); hk5E=t~&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O
'!r]0Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); _r<zSH%  
String sProperty = "bytes="+nStartPos+"-"; _,Rsl$Tk'  
httpConnection.setRequestProperty("RANGE",sProperty); -e`oW.+  
Utility.log(sProperty); IB#iJ#,  
bU:}ZO^S  
M8#*zCp{5  
InputStream input = httpConnection.getInputStream(); !HdvCYB>  
//logResponseHead(httpConnection); j2o1"  
!0!U01SWa  
/.|A  
byte[] b = new byte[1024]; [yYH>~SuwZ  
int nRead; :Er^"9'A2  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :!+}XT7)/  
{ u^aFj%}]L  
nStartPos += fileAccessI.write(b,0,nRead); n,&/D  
//if(nThreadID == 1) {XDY:`vZ}  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Uxk[O  
} ]M+VSU  
Z92iil;t  
:~ZqB\>i  
Utility.log("Thread " + nThreadID + " is over!"); eC+"mhB  
bDownOver = true; jsNH`"  
//nPos = fileAccessI.write (b,0,nRead); =.qm8+  
} 9k=U0]!ch  
catch(Exception e){e.printStackTrace ();} 7g A08M[O  
} I9[1U  
} kb"_6,[Ms  
xb+RRTgj  
qLQ <1>u  
//打印回应的头信息 kvW
|=  
public void logResponseHead(HttpURLConnection con) BrlzN='j}  
{ cQ3W;F8|n  
for(int i=1;;i++) 0|fb< "  
{ n) _dH/"  
String header=con.getHeaderFieldKey(i); }pl]9  
if(header!=null) T}L^CU0  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ci7P%]9  
Utility.log(header+" : "+con.getHeaderField(header)); 7K>D@O  
else "EcX
_>  
break; |+Hp+9J  
} ~Ho{p Oq  
} kCaO\#ta  
,67"C2Y  
A9\]3 LY  
public void splitterStop() 7Sg
weZ}"  
{ b 0LGH. z4  
bStop = true; DU5:+" u3  
} :]CzN^k(1c  
j4~7akG  
c;:">NR  
} (O)\#%,@R  
Q0zW ]a  
{fGd:2dh  
/* \H Wcd|  
**FileAccess.java X,C*qw@  
*//文件访问(定位，写) B :.@Qi^  
package NetFox; s<[A0=LH  
import java.io.*; !c3```*  
EMVk:Vt]  
G'ij?^?  
public class FileAccessI implements Serializable{ R)0N0gH
 
yfmp$GO:  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Nls83 W  
RandomAccessFile oSavedFile; E,{GU  
long nPos; {>8Pl2
J  
[8>z#*B  
BdN8 ^W  
public FileAccessI() throws IOException :83,[;GO2  
{ FJP< bREQ  
this("",0); ^4c,U9J=  
} 0U$:>bQ  
e^j<jV`1
 
c_ La^HS  
public FileAccessI(String sName,long nPos) throws IOException 4p.^'2m  
{ PG{i,xq_B{  
oSavedFile = new RandomAccessFile(sName,"rw"); D`6iDit  
this.nPos = nPos; 95=gY  
oSavedFile.seek(nPos); kOw=c Gt  
} J,f/fPaf7  
zVSx$6eiU  
f}^I=pS&  
public synchronized int write(byte[] b,int nStart,int nLen) \+-zRR0  
{ +'%@!  
int n = -1; bS>R5*Zp  
try{ HF"Eys  
oSavedFile.write(b,nStart,nLen); >~_Jq|KBB  
n = nLen; H&M1>JtE  
} 9B /s  
catch(IOException e) {Fbg]'FQ
 
{ ]eE 1n2  
e.printStackTrace (); ]kx
-,M(  
} pet~[e%!  
JIzY,%`\  
}91*4@B7  
return n; AXs=1 e  
} xq}-m!nX  
\[yr=X  
j&5G\6:  
} >c<pDNt?  
+R!zs  
~g6"'Cya?k  
/* e}c&LDgU  
**SiteInfoBean.java k<H%vg>{~s  
*/ ( #*"c  
package NetFox; ~.J,A\F  
tJNIr5o  
zh\$t]d<I  
public class SiteInfoBean { @}Zd (o  
Gqb])gXpl  
]4`t\YaT  
private String sSiteURL; //Site's URL ;B~P>n}}_]  
private String sFilePath; //Saved File's Path .u l 53 m  
private String sFileName; //Saved File's Name ^i+[m  
private int nSplitter; //Count of Splited Downloading File ]
jyM@  
@Br {!#Wf  
u:@U $:sZ  
public SiteInfoBean() Y25^]ON*\^  
{//nSplitter的缺省值为5 3X;{vO\a1  
//default value of nSplitter is 5 8'A72*dhX  
this("","","",5); >H>gH2qp  
} q/NY72tj0  
#EDEYEW7  
^"9* 'vTtc  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Rf)ke("  
{ B:< ]Hl$  
sSiteURL= sURL; qz!Ph5(  
sFilePath = sPath; ]dSK wxk  
sFileName = sName;  B/G-Yh$E  
this.nSplitter = nSpiltter; /.Fj.6U5  
_%~$'Hy  
54{q.I@n  
} +`B'r '  

3uV4/%U  
@5.e@]>ZM  
public String getSSiteURL() MPIlSMe  
{ ySe$4deJ  
return sSiteURL; n2{SV  
} ib$nc2BPb  
DVlJ*A  
+f>cxA  
public void setSSiteURL(String value) ]5' d&f  
{ ye%iDdf  
sSiteURL = value; _OMpIdY,R*  
} TW7:q83{l  
TJ(K3/)Z  
7AwgJb hn  
public String getSFilePath() x({H{'9?  
{ 9Ma0^_  
return sFilePath; rv>^TR*,!  
} BQ/PGY>  

Md,pDWb  
v.=/Y(J  
public void setSFilePath(String value) h1[WhBL-O  
{ QJn`WSw$_-  
sFilePath = value; C3XmK}h  
} &
H||&Z[pk  
Wh( |+rJ?Z  
x[Im%k  
public String getSFileName() o31Nmy Ni  
{ `y^s
ITr  
return sFileName; -F\qnsZ2  
} %0,-.(h  
+oc >S  
jjzA .8?(7  
public void setSFileName(String value) ]]0,|My7  
{
En6H%^d2  
sFileName = value; p`F9Amb  
} *|% ^0#$c  
B=Ym x2A9]  
. ]@=es  
public int getNSplitter() 2HD]?:Fk7  
{ WG7k(Sp]  
return nSplitter; nV*y`.+  
} +Qxu$#  
71fk.16  
mee$"Y  
public void setNSplitter(int nCount) Zg~nlO2  
{ 5fJ[}~  
nSplitter = nCount; F_;DN: {  
} _oFs #kW  
} A"v
{~  
%JZZ%xc  
ORN6vX(1  
/* "LhvzM-<8  
**Utility.java "O[j!fG8,  
*/ N587(wZ  
package NetFox; o>Er_r  
c{+AJ8  
}8-\A7T  
public class Utility { ZR0r>@M3v<  
nH|,T%  
kS# CEU7  
public Utility() )B# ,  
{ h#r^teui)  
o Y}]UB>  
sP@X g;]  
} FR[ B v  
8eBOr9l+j  
//线程睡眠 v``-F(i$  
public static void sleep(int nSecond) )E#2J$TD  
{ =&wmWy  
try{ d[ >`")2)  
Thread.sleep(nSecond); Ny- [9S-<  
} YevyN\,}V!  
catch(Exception e) M:KbD|  
{ g7V8D  
e.printStackTrace (); l_'[27
 
} N==ZtKj F  
} /cr}N%HZB  
Ys+OB*8AE  
//日志 H5CR'Rp  
public static void log(String sMsg) Kv'n:z7Md  
{
J5p"7bc  
System.err.println(sMsg); 3.d"
rl  
} Y9=K]GB  
)4>2IQ  
J7D}%  
public static void log(int sMsg) B(?Yw>Xd[  
{ =]`lN-rYw  
System.err.println(sMsg); u]-_<YZ'B  
} 1n5(S<T  
} @`opDu!  
:2 >hoAJJ  
0Sq][W
=  
/* '>$EOg"  
**TestMethod.java mR\`DltoV  
*/ Zn=T#o  
package NetFox; kE8>dmH23  
n<sd!xmqFx  
,;?S\V  
public class TestMethod { =gfI!w  
?"#%SKm  
QxuhGA  
public TestMethod() p.I.iAk%G^  
{ ///xx/weblogic60b2_win.exe 7(M(7}EKA  
try{ w=]Ks'C]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Jj~EiA  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =deMd`=J  
SiteFileFetch fileFetch = new SiteFileFetch(bean); b`yZ|j'ikd  
fileFetch.start(); SK1!thQy  
} DFhXx6]  
catch(Exception e){e.printStackTrace ();} e^4 p%  
sDr/k`>  
SG}V[Glk  
} Gb[`R}^dq  
;6@r-r  
2?m.45`  
public static void main(String[] args) :j|IP)-f  
{ gqXS~K9t  
new TestMethod(); 6S6f\gAM  
} dzK{ Z  
} `l2O?U-@  
点击下载更多相关资料