http断点续传简单实现（java)

/* ra8AUj~RX  
**SiteFileFetch.java >sQf{uL  
*/ q#K0EAgC  
package NetFox; P MI?PC[;  
import java.io.*; O"1HO[  
import java.net.*; S[{,+{b0  
qB+OxyT&  
'sTc=*p/  
public class SiteFileFetch extends Thread { \F
)WUIK  
JOyM#g9-?  
%Vfr#j$
=  
SiteInfoBean siteInfoBean = null; //文件信息Bean 58R.`5B  
long[] nStartPos; //开始位置 m~4ik1wq  
long[] nEndPos; //结束位置 "
]W,,A-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 `Om W#\  
long nFileLength; //文件长度 u Yc}eMb  
boolean bFirst = true; //是否第一次取文件 O&sUPv  
boolean bStop = false; //停止标志 ^!$=(jh.  
File tmpFile; //文件下载的临时信息 n`!6EaD  
DataOutputStream output; //输出到文件的输出流 8mt#S  
%S^:5#9  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） AC!yc(^<  
public SiteFileFetch(SiteInfoBean bean) throws IOException nI] zRduC  
{ S5r.so
 
siteInfoBean = bean; [E/. r{S  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); eN`G2eE  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); aSI%!Vg.  
if(tmpFile.exists ()) i=&]%T6Qk  
{ )1 QOA  
bFirst = false; 9A87vs4[  
read_nPos(); /S@iF  
} R G~GVf  
else di7cCn  
{ x6ayFq=  
nStartPos = new long[bean.getNSplitter()]; 5Q:%f  
nEndPos = new long[bean.getNSplitter()]; 
&da:{  
} 'j!n   
]W5p\(1g  
A\v53AT  
"~KTLf  
} >_$_fB  
[zSt+K;  
PEaZ3{-  
public void run() :ciD!Ly  
{ 7Hj7b:3K&!  
//获得文件长度  bDD29  
//分割文件 E33WT{H&_'  
//实例FileSplitterFetch uo(LZUjPbN  
//启动FileSplitterFetch线程 UID`3X  
//等待子线程返回 b
fYVA2=Z  
try{ QZ[S, c^  
if(bFirst) KOoV'YSC[(  
{ 8idIJm%y  
nFileLength = getFileSize(); @LSX@V   
if(nFileLength == -1) u|k_OUTq  
{ f{uS  
System.err.println("File Length is not known!"); ;f=.SJF  
} GL,[32~C  
else if(nFileLength == -2) e [6F }."c  
{ Ggy?5N7P  
System.err.println("File is not access!"); N^AlhR^  
} h")7kjM  
else \7%wJIeyx  
{ HVzkS|^F  
for(int i=0;i<nStartPos.length;i++) EVE"F'Ww,_  
{ hjhZ":I.  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); t_Rj1U  
} ?{xD{f$  
for(int i=0;i<nEndPos.length-1;i++) cob??|,\m  
{ |?hsMN  
nEndPos = nStartPos[i+1]; 8k+k\V{  
} `b%^_@Fb  
nEndPos[nEndPos.length-1] = nFileLength; #K iqV6E  
}
K@Xj)  
} @VyNe(U  
l}k'ZX4  

mx#)iHY  
//启动子线程 sCp)o,;  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; P+C5 
s  
for(int i=0;i<nStartPos.length;i++) Zv*uUe  
{ ` k(Q:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nc1?c1s,f  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), vZs~=nfi#|  
nStartPos,nEndPos,i); vsQvJDna~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _>r(T4}]  
fileSplitterFetch.start(); jhBfy|Ftu  
} *pABdP+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z`|\%D%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); InRcIQT  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -Owb@
Nw  
nEndPos = " + nFileLength); 7Jd&9&O U  
// fileSplitterFetch[nPos.length-1].start(); J6ed  
px(~ZZB
"  
zU!d(ge.E  
//等待子线程结束 [Z&<# -  
//int count = 0; 1=ZQRJW0B  
//是否结束while循环 oel?we6  
boolean breakWhile = false; bH:C/P<x  
73_-7'^mQ  
~QUN O~  
while(!bStop) XQmg^x[,A  
{ 8@|{n`n]  
write_nPos(); Z&=
Oe^  
Utility.sleep(500); 5@ Hg 4.  
breakWhile = true; 51*[Ibx  
z4zPR?%:  
JSaF7(a =  
for(int i=0;i<nStartPos.length;i++) DF-.|-^9I  
{ Og?GYe^_  
if(!fileSplitterFetch.bDownOver) ,]y_[]636  
{ J aJ/|N  
breakWhile = false; +}:2DXy@  
break; 5H|7DVG  
} 6E(..fo:"  
} _c-(T&u<  
if(breakWhile) 0%,?z`UY  
break; CkNh3'<wg  
@W~aoq6  
W@zu
N)U  
//count++; !1A< jL  
//if(count>4) L"0?g(< 5  
// siteStop(); fN:FD`  
} S@y?E}  
H ]!P[?  
;lt8~ea  
System.err.println("文件下载结束！"); uD[T l  
} 09{s'  
catch(Exception e){e.printStackTrace ();} U!E}(9 tb
 
} 2Uu!_n}tNF  
KuL+~  
"|R75m,Id  
//获得文件长度 ic l]H  
public long getFileSize() =EU;%f  
{ zZey
 
int nFileLength = -1; d#W^S
[[  
try{ Lf%}\0:  
URL url = new URL(siteInfoBean.getSSiteURL()); Ug4o2n0sk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1Tev&J  
httpConnection.setRequestProperty("User-Agent","NetFox"); C~.T[Mlu  
kjXwVGK=P<  
s?4nR:ZC}  
int responseCode=httpConnection.getResponseCode(); r`RLDN!`  
if(responseCode>=400) .RyuWh!5  
{ :h!'\9  
processErrorCode(responseCode); >;VZB/d  
return -2; //-2 represent access is error #q-fRZ:P  
} TefPxvd  
/s+S\ djk  
-"^xg"  
String sHeader; rhly.f7N=A  
ug;~dhe~  
| h+vdE8  
for(int i=1;;i++) c\O2|'JzE  
{ e<FMeg7n  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); koE]\B2A6  
//Utility.log(in.readLine()); d>Nh<PqH6  
sHeader=httpConnection.getHeaderFieldKey(i); v!$?;"d+  
if(sHeader!=null) wM3m'# xJ  
{ @Pi]kWW})  
if(sHeader.equals("Content-Length")) 2^w{Hcf  
{ Q}a(vlZ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Z%=A[`5]  
break; 5w+&plIJ  
} <(V~eo e  
} k
Lpq{GUv:  
else lvNi/jk  
break; $xF[j9nM  
} _N>#/v)Yi  
} _+~&t9A!  
catch(IOException e){e.printStackTrace ();} )r)ZmS5O  
catch(Exception e){e.printStackTrace ();} j%J>LeTca  
:2')`xT  
og&h$<uOZt  
Utility.log(nFileLength); k2PK4Ua_}q  
H0.A;`  
*X}2  
return nFileLength; ]^i^L  
} Kc#1H|'2N  
`R-?+76?  
b*{UO  
//保存下载信息（文件指针位置） $jv"$0Fc  
private void write_nPos() <HIM k  
{ {Ve`VV5E  
try{ Iek]/=  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &2O~BIRE  
output.writeInt(nStartPos.length); 2~B5?(g  
for(int i=0;i<nStartPos.length;i++) G-;EB  
{ w*o2lg9  
// output.writeLong(nPos); ?C   
output.writeLong(fileSplitterFetch.nStartPos); i'^! SEt  
output.writeLong(fileSplitterFetch.nEndPos); @L0)k^:  
} zAJC-YC6  
output.close(); `0!%jz=  
} 4T v=sP  
catch(IOException e){e.printStackTrace ();} rq}xuSFI  
catch(Exception e){e.printStackTrace ();} oEj$xm_}  
} BW`;QF<  
U)Tl<l<  
{ 9\/aXPS  
//读取保存的下载信息（文件指针位置） 2t45/:,  
private void read_nPos() .C ,dV7  
{ b^P\Q s*m  
try{ H\9ePo\b~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); P_75-0G  
int nCount = input.readInt(); i*A_Po  
nStartPos = new long[nCount]; bqx2lQf,_  
nEndPos = new long[nCount]; HEhBOER?  
for(int i=0;i<nStartPos.length;i++) )p:
+!sX(  
{ &n0Ag]$P  
nStartPos = input.readLong(); =Mxu,A  
nEndPos = input.readLong(); /g!Xe]Ss  
} $&Z#2 X.  
input.close(); eIN0T;1T  
} P7l3ZH( g  
catch(IOException e){e.printStackTrace ();} t -fmA?\  
catch(Exception e){e.printStackTrace ();} Sl%6F!  
} L 7LUy$M-<  
+V[;DOlll  
E0DquVrz  
private void processErrorCode(int nErrorCode) giW9b_  
{ I }8b]  
System.err.println("Error Code : " + nErrorCode); )a`kL,  
} g@Y]$ey%A  
uf:'"7V7  
K*4ib/'E a  
//停止文件下载 Q:b0!  
public void siteStop() *Ue#Sade  
{ 2:e7'}\D.  
bStop = true; b' ~WS4xlD  
for(int i=0;i<nStartPos.length;i++) .0;\cv4}  
fileSplitterFetch.splitterStop(); :QXKG8^  
Re'3bs:+  
soX^$l  
} Q|2*V1"r<2  
} t"e%'dFv  
//负责部分文件的抓取 U^qS[HM  
**FileSplitterFetch.java :()K2<E  
*/ OIjG`~Rx  
package NetFox; L&uPNcZ`-  
_?$w8 S%  
0(&Rm
R  
import java.io.*; a( N;|<  
import java.net.*; @uG/2'
B(  
c%+uji6  
78?cCj{e  
public class FileSplitterFetch extends Thread { j8rxhToC  
Vh]=sd<F  
X gtn}7N.  
String sURL; //File URL L;+e)I]  
long nStartPos; //File Snippet Start Position CUBL/U\=  
long nEndPos; //File Snippet End Position +[$Td%6  
int nThreadID; //Thread's ID jyidNPLm4  
boolean bDownOver = false; //Downing is over w"O;: `|n  
boolean bStop = false; //Stop identical |tTcJ\bG  
FileAccessI fileAccessI = null; //File Access interface &4l!2  

L%-ENk  
+"~*L,ken0  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0 wDhX  
{ 1(%6X*z  
this.sURL = sURL; Ub4)x  
this.nStartPos = nStart; vu*9(t)EC  
this.nEndPos = nEnd; [lK`~MlQ  
nThreadID = id; K2V?[O#  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 bBGg4{  
} lEb H4 g  
.SOCWznb  
|W&K@g$  
public void run() EZhk(LE  
{ mGoC8t}iP  
while(nStartPos < nEndPos && !bStop)
mD*!<<Sw  
{ P4c}@Mq3  
!FB2\hiM  
1CV?  
try{ :R$v7{1  
URL url = new URL(sURL); XIl#0-E0X  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
{>TAnb?n  
httpConnection.setRequestProperty("User-Agent","NetFox"); x`'s  
String sProperty = "bytes="+nStartPos+"-"; v3kT~uv  
httpConnection.setRequestProperty("RANGE",sProperty); 47A[-&y*X  
Utility.log(sProperty); j)juvat  
57;( P  
s!Iinc^p  
InputStream input = httpConnection.getInputStream(); h///
 
//logResponseHead(httpConnection); Mt%Q5^  
I7t}$S6  
Lw?>1rTT/  
byte[] b = new byte[1024]; V|{~9^  
int nRead; gI@nE:(m  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &b2@+/ F  
{ 5Z#(C#  
nStartPos += fileAccessI.write(b,0,nRead); TY` R_  
//if(nThreadID == 1) ?
,[$8V  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); gb[.Ww  
} \\d8ulu  
RtDTcaW/  
g|4>S<uC  
Utility.log("Thread " + nThreadID + " is over!"); ^?0?*  
bDownOver = true; %(s2{$3  
//nPos = fileAccessI.write (b,0,nRead); ma"M?aM  
} A v;NQt8ut  
catch(Exception e){e.printStackTrace ();} 1 7iw`@  
} Y'R/|:YL@  
} +j$nbU0U  
k9VWyq__  
]J/;Xp  
//打印回应的头信息 ygUX]*m!  
public void logResponseHead(HttpURLConnection con) eQqCRXx  
{ h_g"F

@  
for(int i=1;;i++) z@jKzy
q  
{ Z hCjY  
String header=con.getHeaderFieldKey(i); )_?HBTG  
if(header!=null) UCo<ie\V  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); f&&Ao  
Utility.log(header+" : "+con.getHeaderField(header)); C?6q]k]r  
else -:b<~S[  
break; 2t=&h|6EW  
} 2{g&9  
} {WeRFiQ?-  
jX t5.9 t  
\oP  
public void splitterStop() $ylxl"Y  
{ (;HO3Z".q$  
bStop = true; )k `+9}OO  
} V{}TG]  
F0k
Q/x  
+5kQ;D{+  
} *$mb~k^R  
:U @L$  
|UcF%VNnz1  
/* _~*ba+
{  
**FileAccess.java 7&V3f=aj6  
*//文件访问(定位，写) x3jjtjf  
package NetFox; Dd$8{~h"G  
import java.io.*; azTiY@/  
ZMK1V)ohn  
LXR>M>a`  
public class FileAccessI implements Serializable{ -,$:^4  
oiz]Bd  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ;b_<5S  
RandomAccessFile oSavedFile; vgr5j  
long nPos; \,I{*!hw  
a3He-76  
Q"oJhxS  
public FileAccessI() throws IOException }MM:qR  
{ =knBwjeD  
this("",0); D2\EpL/  
} HDs8M  
:"+3Uk2  
eNm Wul  
public FileAccessI(String sName,long nPos) throws IOException KXu1%`x=%Z  
{ XhOg>  
oSavedFile = new RandomAccessFile(sName,"rw"); mt-t8~A  
this.nPos = nPos; =]<X6!0mR  
oSavedFile.seek(nPos); x\G<R; Q  
} X: Be'  

Maiyd  
a]I~.$G   
public synchronized int write(byte[] b,int nStart,int nLen) M%Q_;\?]  
{ i \.&8  
int n = -1; ^4{{ +G)j  
try{ 5ai$W`6  
oSavedFile.write(b,nStart,nLen); tZr_{F@  
n = nLen; ^j?"0|  
} g{m~TVm'  
catch(IOException e) X(C=O?A  
{ \Fu(IuD  
e.printStackTrace (); JS&;7Z$KX  
} l!}7GWj  
ZYz8ul$E  
N,ZmGzNP)  
return n; .WGrzhsV  
} 01+TVWKX  
2y9$ k\<xV  
SFqq(K2u  
} z_Pq5  
<?!%dV{z  
u4[rA2Bf8E  
/* BR~+CBH  
**SiteInfoBean.java !\q'{x5C  
*/ Ga;Lm?6-  
package NetFox; gZ {  
_P=L| U#C  
QU@CPME  
public class SiteInfoBean { 7t6TB*H  
}wGy#!CSza  
ESkhC
DU  
private String sSiteURL; //Site's URL x0q`Uc  
private String sFilePath; //Saved File's Path Ntpw(E<$f  
private String sFileName; //Saved File's Name !LpFK0rw  
private int nSplitter; //Count of Splited Downloading File .gw6W0\F  
Mbtk:Gu
Y  
U{3Pk0rZ  
public SiteInfoBean() AD"L
>7  
{//nSplitter的缺省值为5 a &hj|  
//default value of nSplitter is 5
Z7dVy8J  
this("","","",5); oX6()FR  
} L^jhr>-";  
5Yx 7Q:D  
%r:Uff@  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;VgB!  
{ PE2O$:b\  
sSiteURL= sURL; U~<~>^[  
sFilePath = sPath; ^W[3RiG  
sFileName = sName; Fr,b5 M<L7  
this.nSplitter = nSpiltter; Ng
\]  
r59BBW)M  
g|x*sZR~Y  
} #lx(F3  
Pb/[945  
PkDh[i9Z|  
public String getSSiteURL() |`@7G`x  
{ lD?]D&  
return sSiteURL; UphZRgT!N  
} ":01M},RA  
Yr 1k\q  

?4lEHef  
public void setSSiteURL(String value) WVh]<?GWXk  
{ 7iH%1f  
sSiteURL = value; X%Ta?(9|.^  
} 7^Y`'~Y^  
[J43]  
v cb}Gk  
public String getSFilePath() | <- t  
{ 3>G"&T{  
return sFilePath; Z(o]8*;Ai  
} QZ_8r#2x  
EdS7m,d  
5OHF=wh  
public void setSFilePath(String value) ]0myoWpi3  
{ vN`JP`IBx  
sFilePath = value; jg=}l1M"  
} F!ra$5u  
3b1%^@,ACy  
xU$15|ny  
public String getSFileName() =}YaV@g<f  
{ 8POLp9>X  
return sFileName; 0tP{
K  
} fZrB!\Q  
{$)pkhJ  
%51HJB}C]  
public void setSFileName(String value) AR5)Uws  
{ MHAWnH8  
sFileName = value; #i[V{J8.p  
} 7>yb8/J  
? -`8w _3  
y_f^ dIK*=  
public int getNSplitter() S *K0OUq  
{ \Gz 79VW  
return nSplitter; rZG6}<Hx  
} qwHP8GU  
_:?b-44  
GQ=Pkko  
public void setNSplitter(int nCount) t[b@P<F  
{ -owap-Va  
nSplitter = nCount; n_46;lD  
} p$@l,4@{  
} "0Yb 2>F  
MnD^jcx   
U&SgB[QHO  
/* rd4mAX6@  
**Utility.java '| bHu  
*/ td\'BV  
package NetFox; gl!F)RdH  
hwd{^  
a3[lZPQe  
public class Utility { T6Ks]6m_  
8WMGuv  
ue"e><c6:  
public Utility() vB1nj<]&z  
{ gatxvR7H  
h9WyQl7  
L$ ZZ]?7j  
} %2EHYBQjN  
LFPYnK  
//线程睡眠 i$S*5+  
public static void sleep(int nSecond) Kma-W{vGD  
{ ;@G5s+<l  
try{ h&m4"HBL_  
Thread.sleep(nSecond); $o>6Io|D  
} =U+_;;F=  
catch(Exception e) k2ZMDU  
{ 2, r{zJ8  
e.printStackTrace (); vy1N,8a  
} R#Hz%/:|A  
} @[w.!GW%  
glgXSOj  
//日志 yu@u0vlc  
public static void log(String sMsg) ~mYCXfoc{  
{ {.D/MdwW;  
System.err.println(sMsg); f&L8<ASFo  
} ^?o>(K  
5!}fd/}Uk  
,S\AUUt%  
public static void log(int sMsg) I vD M2q8f  
{ ]ppws3*Pa  
System.err.println(sMsg); ()%;s2>F  
} &(,-:"{pNR  
} *4RL  
Xrd-/('2  
T96M=?wh!  
/* WTQd}f  
**TestMethod.java <<[\ Rv  
*/ -JfO} DRI  
package NetFox; A6%~
+9  
3IDX3cM9  
-q}I; cH  
public class TestMethod { :dj=kuUTbu  
gtw?u b  
gaxxB]8  
public TestMethod() W#lt_2!j  
{ ///xx/weblogic60b2_win.exe fW8whN  
try{ <-Q0s%mNj,  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5R/k8UZ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); (G`O[JF  
SiteFileFetch fileFetch = new SiteFileFetch(bean); i@hW" [A  
fileFetch.start(); C{P:1ELYXH  
} W"ldQ  
catch(Exception e){e.printStackTrace ();} $>!tpJw  
\R (Yf!>  
vN3uLz'<  
} 25/OV"Z  
?emYLw  
Y5$VWUrB  
public static void main(String[] args)  H=(Zx  
{ |FH|l#bu>  
new TestMethod(); 2;&!]2vo$  
} A_JNj8<6r  
} Trt1M  
点击下载更多相关资料