http断点续传简单实现（java)

/* 'YbE%i}  
**SiteFileFetch.java gzW{h0iRr  
*/ ^liW*F"UY  
package NetFox; |tLD^`bt  
import java.io.*; 3q@JhB  
import java.net.*; (ToD u@p  
lS p"(&  
w0H#M)c  
public class SiteFileFetch extends Thread { :1bDkoK  
(@^ySiU  
{;u+?uY  
SiteInfoBean siteInfoBean = null; //文件信息Bean (w(k*b/  
long[] nStartPos; //开始位置 fsnZHL}=n  
long[] nEndPos; //结束位置 J 48$l(l3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象  [Ne'2z  
long nFileLength; //文件长度 9Nv?j=*$  
boolean bFirst = true; //是否第一次取文件
X$P(8'[9A  
boolean bStop = false; //停止标志 [[N${C  
File tmpFile; //文件下载的临时信息 ~mK+Q%G5  
DataOutputStream output; //输出到文件的输出流 Gp)J[8j  
lt2MB#  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Nx*1m BC  
public SiteFileFetch(SiteInfoBean bean) throws IOException q*a~9.i@  
{ }ksp(.}G  
siteInfoBean = bean; ;g2UIb?{6  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); +7_U(|gO  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0fUsERr1*  
if(tmpFile.exists ()) B~&}Mv  
{ *|CvK&7  
bFirst = false; D8Mq '$-  
read_nPos(); ,PJC FQMR  
} ~MYE8xrId  
else o"A)t=  
{ P-8QXDdr  
nStartPos = new long[bean.getNSplitter()]; LH`2Y,E  
nEndPos = new long[bean.getNSplitter()]; nf&5oE^  
} OpIeo+^X*  
w2('75$J  
CM[83>  
4"!kCUB  
} vfmY>nr  
C"s-ttP   
2:nI4S  
public void run() w5/6+@}  
{ [>3dhj[;  
//获得文件长度 b9
-3  
//分割文件 Y}Y~?kE>M|  
//实例FileSplitterFetch lHTr7uF
(  
//启动FileSplitterFetch线程 zh\"sxL  
//等待子线程返回 9v3n4=gc  
try{ 7kT X  
if(bFirst) tuuwoiQ*`  
{ = 8y,7u)  
nFileLength = getFileSize(); D~M R)z_p~  
if(nFileLength == -1) Vw`Q:qo0:b  
{
E m+&I  
System.err.println("File Length is not known!"); aX|(%1r  
} "sY}@Q7  
else if(nFileLength == -2) @qx$b~%  
{ ~.0'v [N  
System.err.println("File is not access!"); &o1k_!25  
} V*Xr}FE  
else )"6"g9A  
{ 1cRF0MI  
for(int i=0;i<nStartPos.length;i++) e+VE FWz
 
{ h9iQn<lp4.  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ! R3P@,j  
} R?- zJ ;  
for(int i=0;i<nEndPos.length-1;i++) =#<bB)59  
{ X{6a  
nEndPos = nStartPos[i+1]; BB(v,W  
} $4)L~g|  
nEndPos[nEndPos.length-1] = nFileLength; r=AA /n<  
} hk S:_e=  
} koD}o^U#  
u!F\`Gfm_  
r_ B.bK  
//启动子线程 C=cn.CX  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]?oJxW.  
for(int i=0;i<nStartPos.length;i++) e-\/1N84  
{ s| Q1;%Tj  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *n[BBz  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), c813NHW  
nStartPos,nEndPos,i); Z'}%Mkm`i}  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Qc PU{#6  
fileSplitterFetch.start(); NPM2qL9&J  
} ,\a
Lv  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), SB.=x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); }Ya! [tX  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0) F\aJ4Y  
nEndPos = " + nFileLength); imAOYEH7}  
// fileSplitterFetch[nPos.length-1].start(); &}pF6eIar  
UK*v\TMv  
4*5e0:O  
//等待子线程结束 M_2>b:#A*  
//int count = 0; "Ehh9 m1&
 
//是否结束while循环 DBLM0*B  
boolean breakWhile = false; zpeCT3Q5O  
d~h;|Bl[  
u=vBjaN2_w  
while(!bStop) gG}H5uN  
{ E'(nJ  
write_nPos(); ZU+_nWnl  
Utility.sleep(500); /;1O9HJa  
breakWhile = true; Hz==,NR-W  
SBDGms  
FH$q,BI!R  
for(int i=0;i<nStartPos.length;i++) _G'A]O/BZD  
{ 6KXW]a `  
if(!fileSplitterFetch.bDownOver) c14d0x{  
{ B I3fk  
breakWhile = false; <hTHY
 E=  
break; r3-<~k-  
} PB5h5eX  
} "Jg.)1Jw  
if(breakWhile) H270)Cwn+  
break; k_zn>aR$F  
4gNN "  
Iwh0PfWJ  
//count++; :M f8q!Q'  
//if(count>4) v2p0EOS  
// siteStop(); n"D` =  
} [
m6+I9  
fqq4Qc)#U&  
m.! M#x2!  
System.err.println("文件下载结束！"); Di4GaKa/  
} 5;XYF0  
catch(Exception e){e.printStackTrace ();} ED" fi$  
} XuHR  
I.T?A9Z  
DG0I-"s  
//获得文件长度 !cM<&3/  
public long getFileSize() "19#{yX4  
{ Y Q.Xl_  
int nFileLength = -1; lz36;Fp  
try{ 7DoU7I\u  
URL url = new URL(siteInfoBean.getSSiteURL()); |0}7/^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?_A[E]/H  
httpConnection.setRequestProperty("User-Agent","NetFox"); d!Gy#<H  
]7yxXg  
z\" .(fIV  
int responseCode=httpConnection.getResponseCode(); ;Oqf{em];  
if(responseCode>=400) ']+!i a  
{ CmBgay  
processErrorCode(responseCode); >P\eHR,{-  
return -2; //-2 represent access is error 1TR+p? "  
} |B*B>P
#  
lBs-u h  
ABkDOG2br  
String sHeader; YZSQOLN{  
Ldv,(ZV,<  
<j,3D
n  
for(int i=1;;i++) e.%I#rNI  
{ ~9yKMUf  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^,AE;ZT7  
//Utility.log(in.readLine()); Q@>1z*'I  
sHeader=httpConnection.getHeaderFieldKey(i); C<I?4WM  
if(sHeader!=null) Qzo -Yw`=  
{ d^!k{Qx'  
if(sHeader.equals("Content-Length")) I}0?d  
{ !k*B-@F  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _5~|z$GW  
break; _X;,,VEV!  
} ZeU){CB  
} wCR! bZ w  
else ecoI-@CAI  
break; 8sc2r  
} YGLq
~A  
} v~T)g"_|  
catch(IOException e){e.printStackTrace ();} i$@xb_  
catch(Exception e){e.printStackTrace ();} D6&P9e_5  
]BjYUTNm  
E QU@';~8  
Utility.log(nFileLength); fDplYn#  
Qj_)^3`e  
x>TIx[x  
return nFileLength; HR8YPU5  
} I *sT*;U  
V6HZvuXV!  
,Ww}xmq1H  
//保存下载信息（文件指针位置） "5 ~{  
private void write_nPos() sCzpNJ"8  
{ Zy;jp*Q  
try{ ?QJx!'Y,p  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )j~
{P  
output.writeInt(nStartPos.length); K{/i2^4  
for(int i=0;i<nStartPos.length;i++) 8~R.iqLoX  
{ p#]9^oA  
// output.writeLong(nPos); knG:6tQ  
output.writeLong(fileSplitterFetch.nStartPos); O TlqJ  
output.writeLong(fileSplitterFetch.nEndPos); oST)E5X;7  
} i7r)9^y  
output.close(); 8Nyz{T[  
} 'iZwM>l\  
catch(IOException e){e.printStackTrace ();} R3lZ|rxv:  
catch(Exception e){e.printStackTrace ();} JQ0Z%;"  
} [7gz?9VyLF  
xW5`.^5  
5CN=a2&  
//读取保存的下载信息（文件指针位置） JmK )Y# A  
private void read_nPos() %M'`K  
{ { >izfG,\  
try{ g_P98_2f.k  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); y'odn;  
int nCount = input.readInt(); mhhc}dS(H  
nStartPos = new long[nCount]; N~C
Qh=<  
nEndPos = new long[nCount]; |^UQVNJ  
for(int i=0;i<nStartPos.length;i++) JWg.0d$hM  
{ fg#e*7Odn  
nStartPos = input.readLong(); uKM` umE  
nEndPos = input.readLong(); {S9gOg  
} 3?"gfw W  
input.close(); iBbaHU*V  
} $3>Rw/,  
catch(IOException e){e.printStackTrace ();} %po;ih$jr*  
catch(Exception e){e.printStackTrace ();} S}U_uZ$b  
} Y 'X!T8  
&`n:
AR`  
yGt[Qvx#  
private void processErrorCode(int nErrorCode) <@ t
s[p.  
{ >W-xDzJry  
System.err.println("Error Code : " + nErrorCode); mkyYs[  
} ^$O(oE(D  
6c-'CW  
D3dh,&KO\  
//停止文件下载 Bl6I@w  
public void siteStop() s-Yu(X2  
{ uchQv]VB  
bStop = true; T3 ie-G@<  
for(int i=0;i<nStartPos.length;i++) !w%c=V]tV  
fileSplitterFetch.splitterStop(); 8gEp5  
.txtt?ZF2  
yy8BkG(  
}
K\xM%O?  
} gsM$VaF(  
//负责部分文件的抓取 T$2A2gb`  
**FileSplitterFetch.java K3 BWj33  
*/ x  zF  
package NetFox; >\pF5a`  
%u&Vt"6m=  
Qfy_@w]  
import java.io.*; x+
6z9{O  
import java.net.*; 'h6G"=+  
O^-QqCZE  
#'%ii,;wQ  
public class FileSplitterFetch extends Thread { :'ZR!w  
,JK0N_=  
R+uZi~  
String sURL; //File URL 3T]cDVQ_  
long nStartPos; //File Snippet Start Position y4p"LD5%^  
long nEndPos; //File Snippet End Position 44P [P{y  
int nThreadID; //Thread's ID n5A|Zjk;  
boolean bDownOver = false; //Downing is over oowof
i(E  
boolean bStop = false; //Stop identical {%>~ ]9E  
FileAccessI fileAccessI = null; //File Access interface gE@Pb  
Y]`=cR`/"  
XZ@+aG_%q  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (9aOET>GG  
{ 3Q62H+MC  
this.sURL = sURL; B\rY\  
this.nStartPos = nStart; jJ<&!=  
this.nEndPos = nEnd; '\8YH+%It  
nThreadID = id; [Ca''JqrA  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 l6WEx -d  
} DIQ30(MS  
iH-,l  
2RNee@!JJP  
public void run() L7rr/D  
{ dba_(I~y  
while(nStartPos < nEndPos && !bStop) ['\R4H!x  
{ 6q>iPK Jt  
K*Ba;"Ugeg  
.{8[o[w =  
try{ iCiKr aW  
URL url = new URL(sURL); Y_y!$jd(N  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); iY@
}Q "  
httpConnection.setRequestProperty("User-Agent","NetFox"); CXoiA"P  
String sProperty = "bytes="+nStartPos+"-"; WQVU 82b*  
httpConnection.setRequestProperty("RANGE",sProperty); l 7dm@S  
Utility.log(sProperty); 3 I%N4K4  
DpmAB.  
oO?+2pTQV  
InputStream input = httpConnection.getInputStream(); Q!IqvmO  
//logResponseHead(httpConnection); @(6i 1Iwu9  
a6z0p%sIZ  
{e2ZW]  
byte[] b = new byte[1024]; xu-bn  
int nRead; RE4#a2  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) MhE".ZRd  
{ 7oIHp_Zq  
nStartPos += fileAccessI.write(b,0,nRead); "u~` ZV(  
//if(nThreadID == 1) k^K76mB  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [>p!*%m  
} #|
gh  
3A"TpR4f`  
4pXY7+e2'  
Utility.log("Thread " + nThreadID + " is over!"); PuZzl%i P3  
bDownOver = true; mpwh=  
//nPos = fileAccessI.write (b,0,nRead); ;t9_*)[  
} b}Im>n!  
catch(Exception e){e.printStackTrace ();} R1Rk
00Ow:  
} +[n#{;]<  
} R'B_YKHBY  
J7{D6@yLS  
o+}1M  
//打印回应的头信息 X~o;jJC  
public void logResponseHead(HttpURLConnection con) 'NjeF&#6  
{ &DYC3*)Jih  
for(int i=1;;i++) ~0-)S@  
{ pl,XS6mB  
String header=con.getHeaderFieldKey(i); j&S.k  
if(header!=null) 16I[z+RG  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9&^5!R
8  
Utility.log(header+" : "+con.getHeaderField(header)); yCkc3s|DA;  
else -9+$z|K  
break; e&ZTRgYdi  
} a[zVC)N0  
} 525^/d6v  
N|)e {|k  
N&k\X]U  
public void splitterStop() Z)(#D($-  
{ jYAm}_?No  
bStop = true; ZWuNl!l>  
} 9CwtBil<#g  
xp3^,x;\X  

RlvvO  
} G1zP^ogk  
vzSjfv  
Bmt8yR2  
/* b
Y,dWNS:  
**FileAccess.java UHfE.mTjM  
*//文件访问(定位，写) G;/> N'#  
package NetFox; +[ir7?Y.  
import java.io.*; l>i:M#z&  
8?<J,zu@AV  
]1GyEr:  
public class FileAccessI implements Serializable{ 9$[
MM*r  
s`,g4ce`  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {s6#h#U  
RandomAccessFile oSavedFile; rWO#h{  
long nPos; gV:0&g\v  
86qQ"=v  
dn42'(p@G  
public FileAccessI() throws IOException $'!n4}$}  
{ ;&?ITV  
this("",0); (<OmYnm  
} T51oNO%^  
I-J%yutB  
EXW?)_pg  
public FileAccessI(String sName,long nPos) throws IOException M,{;xf  
{ 0$yHO2 f  
oSavedFile = new RandomAccessFile(sName,"rw"); Ae^4  
this.nPos = nPos; >U4bK^/Bp  
oSavedFile.seek(nPos); n@C#,v#^0  
} L4u.cHJ}0  
SZ4@GK  
Ft:_6T%  
public synchronized int write(byte[] b,int nStart,int nLen) $'#}f?  
{ R*ex!u60M  
int n = -1; wc}x [cS  
try{ RJT55Rv{  
oSavedFile.write(b,nStart,nLen); V0#E7u`4  
n = nLen; 0}kvuuR  
} JiA1yt  
catch(IOException e) j~;y~Cx?  
{ EjEXev<]  
e.printStackTrace (); xAn|OSe  
} Ia^/^>  

&Dp&  
3],(oQq^  
return n; 5':j=KQE_  
} geqx":gpx9  
wmP[\^c%$j  
$K|2k7  
} [R~@#I P!  
:c[T@[  
]<fZW"W<q  
/* /cZcfCW  
**SiteInfoBean.java aJ]t1  
*/ oJ=u pnBn-  
package NetFox; ydzvjp=  
Y$3liDeL=  
qNkX:|j  
public class SiteInfoBean { yW_goS0  
M|$A)D1  
$@dPIq4o;}  
private String sSiteURL; //Site's URL U[@B63];0  
private String sFilePath; //Saved File's Path ;q<:iaY9  
private String sFileName; //Saved File's Name CTX%~1_`O  
private int nSplitter; //Count of Splited Downloading File ].gC9@C:$i  
!6s]p%{V  
kN vNV(4  
public SiteInfoBean() @c,=c+-  
{//nSplitter的缺省值为5 xz/G$7q7  
//default value of nSplitter is 5 5pE@Ww  
this("","","",5); Nn5sD3z#  
} Oo%%f+  
u,@x7a,z  
XToYtdt2  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <,nd]a  
{ 7^h*rL9  
sSiteURL= sURL; V}G;oz&>)  
sFilePath = sPath; .ityudT<  
sFileName = sName; vRO`hGH  
this.nSplitter = nSpiltter; V4%7
Xj  
4-xg+*()  
}GGH:v
 
} r
*ry8QA  
sQY0Xys<4  
Bq\WG=Fd  
public String getSSiteURL() /9C>{29x!  
{ LS1}j WU!  
return sSiteURL; gHU0Pr9'  
} qI\B;&hr(  
V ;M'd@  
b=Q%Jxz?  
public void setSSiteURL(String value) YccD^w[`B  
{ 
T:udw  
sSiteURL = value; }/.b@`Dh;  
} Y{m1\s/o  
rP&.`m88n  
N5fMMi(O  
public String getSFilePath() oVnHbvP1X  
{ `q1K%id  
return sFilePath; ezk:XDi4  
} |F>'7JJJ  
*IC9))PGJ  
rEZMX2  
public void setSFilePath(String value) hKp-"  
{ W#<ZaGsq  
sFilePath = value; :B4X/  
} |Iq\ZX%q  
]3yaIlpD1  
>K;C?gHo  
public String getSFileName() ljj}XJQ  
{ <F5x}i~(C  
return sFileName; N%QVkuCbM  
} &#[6a&9#[A  
80O[pf*?  
Z<tJ+  
public void setSFileName(String value) V8J!8=2  
{ ,O"zz7  
sFileName = value; ;z^C\=om  
} Ha/-v?E  
?bK^IHh  
W6uz G  
public int getNSplitter() ;(9q, )  
{ kA<58,!  
return nSplitter; Y-c_ 2 )  
} C+c;UzbD  
t[^68]  
e?!A]2  
public void setNSplitter(int nCount) "zBYhZr  
{ FDO$(&  
nSplitter = nCount; D7b] ;Nf\  
} Ja#ti y  
} :+\B|*T2.L  
VSa#X |z  
b\9}zmG[u  
/* q%GlS=o"  
**Utility.java o%=OBTh_  
*/ TW?A/GoXI  
package NetFox; Ny)!uqul*  
FQCz_z  
'0>w_
ge4  
public class Utility { 2q.J1
:lW  
&8uq5uKg  
*J] }bX  
public Utility() '\.fG\xD  
{ ( RCQbI  
Qf}b3WEAI  
^iaG>rvA  
} 8!{F6DG  
$17utJ58  
//线程睡眠 J(\f(jh/  
public static void sleep(int nSecond) elf2!  
{ F&x9.  
try{ %B'*eBj~fw  
Thread.sleep(nSecond); 8yV?l7  
} =E''$b?Em  
catch(Exception e) juQQ  
{ }_L,Xg:I  
e.printStackTrace (); Fm3B8Int  
} Ks@  
} *XZlnO  
4r'f/s8"#  
//日志 ]%VR Nm
 
public static void log(String sMsg) 1zUo.Tg0  
{ oO8V0VE\  
System.err.println(sMsg); *^q%b/f  
} m.A_u7D@  
+WYXj  
K7H`Yt  
public static void log(int sMsg) (\<#fkeH  
{ CPCjY|w7   
System.err.println(sMsg); .A`Q!  
} 2'zYrdem  
} ]ozZW:  
IirXF?&t  
co$I htOv  
/* yBwgLn  
**TestMethod.java Td !7Rx _  
*/ VMZ"i1rP  
package NetFox; 
%4~2  
],HF)21  
q'%-8t  
public class TestMethod { ({}JvSn1  
eS/4gM7%  
fH/J8<  
public TestMethod() 2Po e-=  
{ ///xx/weblogic60b2_win.exe " E U[Lb  
try{ 8f37o/L  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); |lOH PA  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); \,i?WgWv  
SiteFileFetch fileFetch = new SiteFileFetch(bean); J`*!U4  
fileFetch.start(); b]Xc5Dp{  
} ,dM}B-  
catch(Exception e){e.printStackTrace ();} { ke}W  
mPy=,xYyC  
@3hA\3ot^  
} pPNU0]/  
"Y Z B@  
{>E`Zf:  
public static void main(String[] args) &xG>"sJ  
{ wua`e <"  
new TestMethod(); dd +%d  
} 1 U|IN=  
} VgHVj)ir  
点击下载更多相关资料