http断点续传简单实现（java)

/* |?>h$'  
**SiteFileFetch.java 7Tbkti;  
*/ vEsSqzc  
package NetFox; 2R!W5gs1<  
import java.io.*; }FXRp=s  
import java.net.*; 3
XRG"  
D6t]E)FH  
RBXoU'.  
public class SiteFileFetch extends Thread { !=we7vK}  
QZlUUj\   
6D0,ME#  
SiteInfoBean siteInfoBean = null; //文件信息Bean DXt^Ym5Cv  
long[] nStartPos; //开始位置 1<83MO;  
long[] nEndPos; //结束位置 2XtQ"`)  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 eG v"&kr  
long nFileLength; //文件长度 zN1;v6;  
boolean bFirst = true; //是否第一次取文件 ,b4&$W].  
boolean bStop = false; //停止标志 3Z0\I\E  
File tmpFile; //文件下载的临时信息 [xPE?OD  
DataOutputStream output; //输出到文件的输出流 A@ME7^w7  
D\R^*k@V  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） sn(}5;  
public SiteFileFetch(SiteInfoBean bean) throws IOException `9-Zg??8r  
{ J$;)TI  
siteInfoBean = bean; }>w4!  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 4Z] 35*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); C#Jj;Gd  
if(tmpFile.exists ()) %vXQ Sz  
{ K="+2]{I  
bFirst = false; NSq=_8  
read_nPos(); U~m.I  
} zMKL: Um"  
else (a?Ip)`I  
{ oB9m\o7$  
nStartPos = new long[bean.getNSplitter()]; 0=B5 =qyw  
nEndPos = new long[bean.getNSplitter()]; gISs+g  
} ${wE5^ky  
MeX1y]<It  
@XmkIm  
67x^{u
7  
} jH1~Ve+q9  
:X f3wP=  
R.N*G]K5  
public void run() OxZ:5ps  
{ &U
R/Txnu  
//获得文件长度 U:r2hqegd  
//分割文件 OT i3T1&  
//实例FileSplitterFetch BP$#a
#  
//启动FileSplitterFetch线程 "+&<Qd2  
//等待子线程返回 ;>N ~,Q  
try{ z3]U%y(,  
if(bFirst) 639k&"V  
{ V{{x~Q9  
nFileLength = getFileSize(); _3a 5/IZ  
if(nFileLength == -1) 3iw9jhK!W  
{ j&.BbcE45  
System.err.println("File Length is not known!"); 7krA+/Qr(  
} d}_c(  
else if(nFileLength == -2) 7w,FA  
{ Ks
(U]G"V  
System.err.println("File is not access!"); U5"OhI  
} yxbTcZ  
else ?W_U{=anl  
{ @g~sgE}#  
for(int i=0;i<nStartPos.length;i++) aehMLl9cl  
{ OWsYE?  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Kf#!IY][  
} sjm79/  
for(int i=0;i<nEndPos.length-1;i++) W+?[SnHL/  
{ 9DX3]Z\7X  
nEndPos = nStartPos[i+1]; S!_?# ^t  
} ]?{lQ0vw'w  
nEndPos[nEndPos.length-1] = nFileLength; AH
J;>"]  
} /&7Yi_]r  
} #LJ-IDuF!  
Ck?:8YlF  
W?-BT >#s  
//启动子线程 vq1&8=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ,np`:fBMy  
for(int i=0;i<nStartPos.length;i++) ;0}2@Q2@ZK  
{ mC92J@m/L!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), PBtU4)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), E e>j7k.G.  
nStartPos,nEndPos,i);
uW=NH;u  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "~C#DZwt{  
fileSplitterFetch.start(); D5u"4\g<&  
} #Ca's'j&f  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q%Q?q)x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3:lp"C51  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", nX%'o`f  
nEndPos = " + nFileLength); EG4bFmcs  
// fileSplitterFetch[nPos.length-1].start(); [t{#@X  
%PbqASm  
\[1CDz=}1  
//等待子线程结束 r:4IKuTR  
//int count = 0; E2'e}RQ  
//是否结束while循环 Tj5@OcA$  
boolean breakWhile = false; J5_Y\@  
WG}CPkj  
I?Fa
  
while(!bStop) +t4m\/y  
{ DAHf&/JK  
write_nPos(); vqMk)htIz  
Utility.sleep(500); 5KE%@,k k  
breakWhile = true; Ml?)Sc"\7  
PRC)GP&q  
/? 1Yf  
for(int i=0;i<nStartPos.length;i++) L^1q/4${  
{ z.&%>%TPP  
if(!fileSplitterFetch.bDownOver) N09+idg  
{ Mk/!,N<h#  
breakWhile = false; h./vTNMc  
break; )=nPM`Jn.  
} !r obau7  
} /(ju  
if(breakWhile) +WN>9V0H  
break; [.xk
 
cjC6\.+l3  
oV>AFs6  
//count++; zy6(S_j  
//if(count>4) a<jE25t  
// siteStop(); |#:dC #  
} ZHECcPhz  
:*:fun  
kah3Uhr~  
System.err.println("文件下载结束！"); %%cSvPcz  
}  Cmx2/N  
catch(Exception e){e.printStackTrace ();} F%Umau*1  
} p6Dv;@)Yn
 
wx%nTf/Oa  
^@lg5d3F  
//获得文件长度 m:fouMS  
public long getFileSize() 124L3
AG  
{ ivz9R'  
int nFileLength = -1; {-N9
0Oe  
try{ pkfOM"5'  
URL url = new URL(siteInfoBean.getSSiteURL()); A2:){`Mw  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .4re0:V  
httpConnection.setRequestProperty("User-Agent","NetFox"); i~B@(,  
=#2qX>?  
^}/ E~Sg7\  
int responseCode=httpConnection.getResponseCode(); W$Q)aA7  
if(responseCode>=400) ,9tbu!Pvq  
{ %_R|@cyD  
processErrorCode(responseCode); ^Xy$is3  
return -2; //-2 represent access is error <C"N X  
} ,x"yZ  
QC5f:BwM  
^Z4q1i)JO  
String sHeader; l3?,gd.-  
Rk jKIa  
:Mu8W_  
for(int i=1;;i++) &Dg)"Xji  
{ u4,X.3V]A  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); b}&7~4zw  
//Utility.log(in.readLine()); +}XL>=-5  
sHeader=httpConnection.getHeaderFieldKey(i); ciGpluQF  
if(sHeader!=null) N!Wq}#&l  
{ N' $DE  
if(sHeader.equals("Content-Length")) Z++Z@J"  
{ 5*wApu{2A  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); h9BD ^j  
break; a;'E}b{`F  
} x #X#V\w=  
} A6UdWK  
else a}qse5Fr  
break; M`+e'vdw  
} k CW!m  
} gUH'DS]{  
catch(IOException e){e.printStackTrace ();} RnA&-\|*  
catch(Exception e){e.printStackTrace ();} Bw]L2=d  
9
p\Hx#^  
MHnf\|DX  
Utility.log(nFileLength); 5 2@udp  
nl-t<#z[  
Q_]!an(  
return nFileLength; $dZ>bXUw:  
} 5}MlZp  
ELrZ8&5G  
"gbnLKs  
//保存下载信息（文件指针位置） q?Ku}eID3  
private void write_nPos() UC+7-y,
  
{ `mKlv~$1^  
try{ > 0Twr  
output = new DataOutputStream(new FileOutputStream(tmpFile)); BsK|:MM]  
output.writeInt(nStartPos.length); aFr!PQp4{  
for(int i=0;i<nStartPos.length;i++) k99gjL`  
{ b1+hr(kMRM  
// output.writeLong(nPos); 9oje`Ay  
output.writeLong(fileSplitterFetch.nStartPos); A eGG  
output.writeLong(fileSplitterFetch.nEndPos); Cb )=n6  
} hViprhC  
output.close(); =|gJb|?w  
} s la*3~?*  
catch(IOException e){e.printStackTrace ();} ])QO%  
catch(Exception e){e.printStackTrace ();} jV4hxuc$  
} VM!-I8t  
~N{_N95!2@  
uhTKCR~  
//读取保存的下载信息（文件指针位置） ~.W=  
private void read_nPos() ,a9D~i 9R  
{ *dG}R#9Nv  
try{ FYXw$7'l  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); T\2) $  
int nCount = input.readInt(); +24|_Lx0  
nStartPos = new long[nCount]; 3b|7[7}&  
nEndPos = new long[nCount]; o%Uu.P  
for(int i=0;i<nStartPos.length;i++) > h,y\uV1  
{ N /sEec  
nStartPos = input.readLong(); O>SuZ>g+7  
nEndPos = input.readLong(); k(-Z@  
} CQBT::  
input.close(); C7b 5%a!  
} 9
5$pG/o  
catch(IOException e){e.printStackTrace ();} 6^]`-4*W  
catch(Exception e){e.printStackTrace ();} @Xq&t}*8  
} "M9TB. O  
V~J*49t&2J  
l$qStL*8O  
private void processErrorCode(int nErrorCode) YeRcf`  
{ }>{ L#JW  
System.err.println("Error Code : " + nErrorCode); om".j  
} ` $.X[\*U  
`z3|M#r\;  
$ DDSN  
//停止文件下载 } g3HoFC  
public void siteStop() QmH/yy3.%  
{ qE#&)  
bStop = true; qPXANx<^  
for(int i=0;i<nStartPos.length;i++) zdLVxL>87  
fileSplitterFetch.splitterStop(); I;kf #nvao  
UM4@H1  
#$rf-E5g-K  
} 00`bL  
} kZU"Xn  
//负责部分文件的抓取 B^
imG  
**FileSplitterFetch.java YW8K $W  
*/ W>p\O9BG  
package NetFox; 5E]UI YAkV  
hi;WFyJTu  
wUZQB1$F  
import java.io.*; NK+FQ^m[  
import java.net.*; '^Pq(b~  
(j8GiJ]{L,  
u;+%Qh  
public class FileSplitterFetch extends Thread { pG,<_N@P  
",~ b2]ym  
]PR|d\O  
String sURL; //File URL K,x$c %  
long nStartPos; //File Snippet Start Position tr}KPdE  
long nEndPos; //File Snippet End Position K[Yc<Q  
int nThreadID; //Thread's ID z3^RUoGU  
boolean bDownOver = false; //Downing is over 7XUhJN3n  
boolean bStop = false; //Stop identical VFilF<jvu  
FileAccessI fileAccessI = null; //File Access interface PU^[HC*K  
W:VW_3  
*C4~}4WT\  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException
q?;N7P  
{ I6K7!+;2  
this.sURL = sURL; ,pDp>-vI%  
this.nStartPos = nStart; gf:vb*#Wa  
this.nEndPos = nEnd; lp:_H-sG  
nThreadID = id; 5h|'DOx|o  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ,3VG.u;U   
} (y=dR1p  
ltNuLZ  
DapQ}2'_  
public void run() I`/]
@BdgY  
{ dzgs
%qtK  
while(nStartPos < nEndPos && !bStop) PzIy">plm  
{ R&NpdW N  
4|zd84g  
b%3Q$wIJ6  
try{ W:`5nj]H9  
URL url = new URL(sURL); 6b%`^B\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l*QIoRYFW  
httpConnection.setRequestProperty("User-Agent","NetFox"); - waX#UT=  
String sProperty = "bytes="+nStartPos+"-"; rU; g0'4e  
httpConnection.setRequestProperty("RANGE",sProperty); *mf}bTiS  
Utility.log(sProperty); k!Vn4?B"k  
ow-+>Y[qZ  
Ezi' 2S
c  
InputStream input = httpConnection.getInputStream(); "I5uDFZR&  
//logResponseHead(httpConnection); |*%/ovg+  
jZa25Z00  
>oe4mW  
byte[] b = new byte[1024]; B1y<.1k  
int nRead; 6eD(dZ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) TRSOO}  
{ h^['rmd  
nStartPos += fileAccessI.write(b,0,nRead); 9TqnzD  
//if(nThreadID == 1) W=~id"XtJ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "w;08TX8  
} =8O}t+U  
zXQVUhL6  
3|q2rA  
Utility.log("Thread " + nThreadID + " is over!"); 86
/.8  
bDownOver = true; ktN%!Mh\  
//nPos = fileAccessI.write (b,0,nRead); kclp}  
} XlRw Z/Wc  
catch(Exception e){e.printStackTrace ();} W7%p^;ZQ$  
} zs4>/9O  
} P`}$-#DF  
Pg7>ce  
e%pu.q\gK  
//打印回应的头信息 %'$f ?y  
public void logResponseHead(HttpURLConnection con) IZ+*`E  
{ (2: N;  
for(int i=1;;i++) : @s8?eg  
{ +:}kZDl@ X  
String header=con.getHeaderFieldKey(i); T:c7@^=  
if(header!=null) ex.+'m<g  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &8Zeq3~  
Utility.log(header+" : "+con.getHeaderField(header)); T0g0jr{  
else 1JIG+ZNmd  
break; VxNXd?  
} uH$oGY  
} ]GcV0&|  
z|uOJ0uK  
]n~yp5Nbr  
public void splitterStop() eUYZxe :6  
{ P=2wkzeJj  
bStop = true; w(/7Jt$  
} sD{j@WEZ  
bdCykG-  
x,w8r+~5  
} yXkt:O,i  
I[@ts!YD  
?vvG)nW  
/* ^Fn%K].
X  
**FileAccess.java Bu&So|@TL  
*//文件访问(定位，写) [Uswf3  
package NetFox;
S[Vtq^lU  
import java.io.*; |0lLl^zp  
kPWBDpzN  
$Tfm/=e  
public class FileAccessI implements Serializable{ >Dxe>Q'df  
87pnSj/X"  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 'gYg~=  
RandomAccessFile oSavedFile;
;;M"hI3@  
long nPos; ]7*k
Wc2  
;3mL^  
Is ot4HLM  
public FileAccessI() throws IOException B`#*o<eb  
{ 2_wvC  
this("",0); su}&".e^  
} Z A[)  
00"CC  
{ E^U6@  
public FileAccessI(String sName,long nPos) throws IOException oI*d/*  
{ DjY8nePyE  
oSavedFile = new RandomAccessFile(sName,"rw"); P`tyBe#=  
this.nPos = nPos; \Fq1^ 8qa  
oSavedFile.seek(nPos); hv3;irK]&  
} <Kg2$lu(_`  
-'j7SOGk  
eap8*ONl  
public synchronized int write(byte[] b,int nStart,int nLen) (nq^\ZdF  
{ _p0)vT  
int n = -1; f$vwuW  
try{ ?HV}mS[t  
oSavedFile.write(b,nStart,nLen); as(;]  
n = nLen; \Yd4gaY\o  
} P:qz2Hw  
catch(IOException e) nX)f'[ 7  
{  >9{zQf!  
e.printStackTrace (); pziq
0  
} 76_<xUt{  
YKY2Cw  
]W;:|/,c  
return n; H$Kw=kMw  
} i@XB&;*c\  
P<vo;96JT  
##v`(#fu  
} 7LfcF  
)(lJT&e  
<1K7@Tu  
/* 3-iD.IAUm@  
**SiteInfoBean.java IytDvz*|  
*/ g>yry}>04%  
package NetFox; /
9Z!p  
M
1EOnq4-  

#~S>K3(  
public class SiteInfoBean { 6Kp}_^|z  
@`S.@^%7fO  
w:Ra7ExP  
private String sSiteURL; //Site's URL iy}xICt  
private String sFilePath; //Saved File's Path Q(e{~ ]*  
private String sFileName; //Saved File's Name O
5M2`6|As  
private int nSplitter; //Count of Splited Downloading File D#ZPq,f  
eVx~n(m!}  
Y.NE^Vn0  
public SiteInfoBean() 6A?8tm/0  
{//nSplitter的缺省值为5 $it@>L8
  
//default value of nSplitter is 5 !9D1 Fa  
this("","","",5); {yS;NU`2  
} ws[/  
7E\g &R.  
T)~!mifX  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) -=a[J;'q  
{ \E77SO,$  
sSiteURL= sURL; Mb.4J2F?  
sFilePath = sPath; H{%H^t>  
sFileName = sName; T pD;  
this.nSplitter = nSpiltter; *{|$FQnR>(  
oqYt/4^Q  
`7\H41%\pp  
} m]P/if7  
d8o ewkiR  
b
]i>Bv  
public String getSSiteURL() vY_eDJ~'  
{ tF%QH[  
return sSiteURL; uXpv*i{R  
} '%&z.{  
@vt$MiOi  
~j"3}wXc5  
public void setSSiteURL(String value) , D"]y~~I5  
{ (:n|v%  
sSiteURL = value; (v^Z BM_  
} "mA1H]r3  
+>}o;`
hPe  
R$d7\nBG  
public String getSFilePath() p/&HUQQk  
{ P0 b4Hq3  
return sFilePath; ({ k7#1 h8  
} jkt6/H  
(A4&k{C_  
e2wvc/gG6  
public void setSFilePath(String value) F&az":  
{ H%z/v|e6  
sFilePath = value; PJK9704 6  
} *
HeVACxo  
S3y246|4  
]2$x|#Gg}  
public String getSFileName() O|e}   
{ l'uOORI  
return sFileName; $8g42LR'  
} p9iu:MucD<  
V;;#/$oU:4  
N}mh}  
public void setSFileName(String value) ~},W8\C>  
{ Z0\Iyc G  
sFileName = value; I_>`hTiR  
} v2>Z^  
#&BS ?@  
niz'b]] +  
public int getNSplitter() wE6A 7\k%  
{ 328L)BmW  
return nSplitter; V|: qow:F  
} Z&Pu8zG /m  
lDN?|YG  
q3+8]-9|5  
public void setNSplitter(int nCount) D/:3RZF  
{ %*K;np-q{  
nSplitter = nCount; T8Na]V5  
} tvpN/p  
} +|&0fGv;d9  
$.8
H>c  
(a#pvEY  
/* 0Oap39  
**Utility.java 6tm\L  
*/ O{q&]~,  
package NetFox; vRr9%zx  
V
3uXan_  
B^q<2S;  
public class Utility { Z@M6!;y#  
\fi}Q\|C  
<5IQc[3]aP  
public Utility() (Ilsk{aB;A  
{ 0*yJ %  

S>t>6
&A  
OZOb1D  
} [r9d<Zi}{  
nzuF]vo  
//线程睡眠 xS+rHC  
public static void sleep(int nSecond) ~Z/7pP+  
{ "% Y u wMY  
try{ >| m.?{^  
Thread.sleep(nSecond); fp;a5||5  
} bEI!Ja  
catch(Exception e) >r}Vf9 5[N  
{ ]sL45k2W  
e.printStackTrace (); dG0VBE  
} KB[QZ`"%!  
} e U;jP]FA  
XwPx9+b6j  
//日志 hY=I5[*  
public static void log(String sMsg) (>AFyh&3,X  
{ Dbz]{_Y;  
System.err.println(sMsg); 0roCP=;  
} QO,+ps<  
[:B*6FXMN~  
88o:NJ}_  
public static void log(int sMsg) c<jB6|.=2  
{ /gw Cwyo  
System.err.println(sMsg); i@,]Z~]  
} T4GW1NP  
} N`1r;%5  
lRND  
r/PKrw sC  
/* !G+u j(  
**TestMethod.java :-Wv>V\t  
*/ 8&.-]{Z  
package NetFox; JXm?2/  
XeU<^ [  
8R4qU!M  
public class TestMethod { )`Ed_F}k  
p+<}Y
DMb  
K\^&+7&zVg  
public TestMethod() t.U{Bu P  
{ ///xx/weblogic60b2_win.exe Pz`hX$  
try{ \
]8i}E1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #U@| J}a  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); t?3BCm$Mi  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?D=8{!R3  
fileFetch.start(); gp/YjUH7k8  
} n(R_#,Hs  
catch(Exception e){e.printStackTrace ();} p(?3 V  
ps+:</;Z  
)4uq iA6  
} y<M]dd$  
:hP58 }Q$  
* nCx[  
public static void main(String[] args) 9L HuS  
{ Tz` ,{k  
new TestMethod(); g+|Bf&_  
} 4_Y!elH)  
} 5;Ia$lm=y  
点击下载更多相关资料