http断点续传简单实现（java)

/* H/W&a2R^P  
**SiteFileFetch.java Bk.`G)t  
*/ S+6YD0  
package NetFox; 0V8G9Gj  
import java.io.*; Q$'\_zV  
import java.net.*; ?vD<_5K;I  
ML$#&Z@ *7  
j&.JAQ*2;  
public class SiteFileFetch extends Thread { Tf$>^L  
/L$q8+  
3- d"-'k  
SiteInfoBean siteInfoBean = null; //文件信息Bean R(y`dQy<K  
long[] nStartPos; //开始位置 nx`W!|g$`  
long[] nEndPos; //结束位置 lr)MySsu#H  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 <.lN'i;(  
long nFileLength; //文件长度 y&4im;X0  
boolean bFirst = true; //是否第一次取文件 >4>. Ycp  
boolean bStop = false; //停止标志 PMQ31f/zf  
File tmpFile; //文件下载的临时信息 <;+QK=f  
DataOutputStream output; //输出到文件的输出流 zYPvpZV/  
_6nza)OFH  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 
@$QtY(a  
public SiteFileFetch(SiteInfoBean bean) throws IOException hI<$lEB  
{ c&RiUU7  
siteInfoBean = bean; c7?|Tipc  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); H lFVc  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); k ;vOPcw  
if(tmpFile.exists ()) [daR)C  
{ b1e)w?n  
bFirst = false; :SF8t`4`  
read_nPos(); R*dXbI&,e  
} Ax!@vL&@  
else ^CDh! )  
{ Bt\V1)  
nStartPos = new long[bean.getNSplitter()]; I.6#>=  
nEndPos = new long[bean.getNSplitter()]; j\.pS^+  
} ^=cXL  
/xA`VyH
O  
'HvW&~i(  
ER]C;DYX  
} ocp3JR_0  
7V\M)r{q7  
r_a1oO:  
public void run() #eI`l`}  
{ +(q r{G?  
//获得文件长度 ,qgR+]?({  
//分割文件 7BA9zs392  
//实例FileSplitterFetch aJNsJIY+  
//启动FileSplitterFetch线程 ).C>>1ZC  
//等待子线程返回 
k|_ >I  
try{ .W-=VzWX  
if(bFirst) OHF:
E44k  
{ 79lG~BGE  
nFileLength = getFileSize(); Me,AE^pgL'  
if(nFileLength == -1) /8(t:  
{ IP1{gMG  
System.err.println("File Length is not known!"); 9JC8OSjJ  
} !.{{QwZ  
else if(nFileLength == -2) i6h0_q
8 >  
{ 6ozBU^n  
System.err.println("File is not access!"); w$I$xup  
} ~Oj-W6-+&,  
else );F /P0P  
{ @(tiPV  
for(int i=0;i<nStartPos.length;i++) D>q?My  
{ ;}4e+`fF|  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1\,wV,  
} I1Gk^wO  
for(int i=0;i<nEndPos.length-1;i++) 0jefV*3qpB  
{ '-X913eG!  
nEndPos = nStartPos[i+1]; vC5 (  
} e-{4qt  
nEndPos[nEndPos.length-1] = nFileLength; Q#$dp  
} T^ah'WmNw
 
} xF9PjnWF=  
$0E_4#kwB  
1T7;=<g`  
//启动子线程 }JWk?  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; &]'<M  
for(int i=0;i<nStartPos.length;i++) P\|i<Ds_M  
{ [Hp"a^~r|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3D7phq>.q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), F a'2i<  
nStartPos,nEndPos,i); Uw_z9ZL  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /`VtW$9-  
fileSplitterFetch.start(); .mS'c#~5Y  
} #T)gKp  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), i_;]UvP  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); x~O_v  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", n1)m(,{  
nEndPos = " + nFileLength); ,7Lu7Q  
// fileSplitterFetch[nPos.length-1].start(); QVrMrm+vRv  
*(@[E  
rU1{a" {  
//等待子线程结束 $y*["~TJ  
//int count = 0; m&#a M8:\  
//是否结束while循环 %g&i.2v  
boolean breakWhile = false; -@_V|C'?  
S)\%.~ n  
ep"54o5=d  
while(!bStop) #6<9FY#  
{ 9Lxj ]W2^  
write_nPos(); ]hkway  
Utility.sleep(500); NCysYmt  
breakWhile = true; Ijj]_V{,  
[HhdeLOX  
f9 b=Zm'  
for(int i=0;i<nStartPos.length;i++) m)9qO7P  
{ 68LB745  
if(!fileSplitterFetch.bDownOver) lTv_%hUp  
{ !M&B=vk4  
breakWhile = false; G(~"Zt}?  
break; (yel  
} M e  
} U8KEg)Msk  
if(breakWhile) f)+fdc  
break; L$+ap~ld  
SW%d'1ya  
9WuKW***  
//count++; zZ=.riK  
//if(count>4) :xT=uE.I  
// siteStop(); Ls^$E  
} 9m fYB  
e$^O_e  
7L:$Amb_F  
System.err.println("文件下载结束！"); ;-d :!*  
} M-df Gk  
catch(Exception e){e.printStackTrace ();} 6!n%SUt  
} b1;80P/:D  
)xQA+$H#4  
[ Q6v#I  
//获得文件长度 1vQj` F  
public long getFileSize() [Hww3+~+  
{ ukSi9| 1-,  
int nFileLength = -1; 8W"~>7/>D  
try{ eS jXaZh  
URL url = new URL(siteInfoBean.getSSiteURL()); 5sq#bvfJ o  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); f13%[RA9N  
httpConnection.setRequestProperty("User-Agent","NetFox"); d(L u|/~  
{ L
JRdV  
ZIx,?E+eJ  
int responseCode=httpConnection.getResponseCode(); l~M86 h  
if(responseCode>=400) bgm$<;`U  
{ /*lSpsBn  
processErrorCode(responseCode); &6E^<v?]  
return -2; //-2 represent access is error Gu:aSb  
} s3G3_&  
|!)3[<.  
g9;}?h  
String sHeader; NTVdSK7z~H  
*r+i=i8{  
zKWcDbj  
for(int i=1;;i++) fD<3Tl8U0  
{ }IGr%C(3%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); kN>AY'1  
//Utility.log(in.readLine()); G?MNM-2  
sHeader=httpConnection.getHeaderFieldKey(i); 7b,u|F  
if(sHeader!=null) >w?O?&Q$  
{ !58-3F%P  
if(sHeader.equals("Content-Length")) w7"Z@$fs  
{ KwRO?G9&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); QP?Z+P<  
break; .Tdl'y:..  
} y@G5I>v  
} Px}#{fkS  
else mMw&{7b:  
break; #kV`G.EX  
} W&6P%0G/  
} -~ `5kO~  
catch(IOException e){e.printStackTrace ();} 2Fce| Tn  
catch(Exception e){e.printStackTrace ();} It4J\S
 
@M"h_Z1#  
pVw)"\S%  
Utility.log(nFileLength); c|Nv^V*2  
d3(T=9;f2  
x1$tS#lS  
return nFileLength; mD)_quz.sk  
} ~'HwNzDQc  
Ajhrsa\~a  
gBq,So  
//保存下载信息（文件指针位置） %?C{0(Z{  
private void write_nPos() gRKmfJ*u  
{ +MeEy{;  
try{ JF_\A)<ki  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5HioxHL  
output.writeInt(nStartPos.length); Xt/muV  
for(int i=0;i<nStartPos.length;i++) oG5JJpLT  
{
PZRpH  
// output.writeLong(nPos); V2'(}k  
output.writeLong(fileSplitterFetch.nStartPos); #T n~hnW  
output.writeLong(fileSplitterFetch.nEndPos); ^c^9kK'
 
} BRV /7ao="  
output.close(); t}`|\*a  
} ]`y4n=L
.  
catch(IOException e){e.printStackTrace ();} Kig.hHj@  
catch(Exception e){e.printStackTrace ();} `yHV10  
} VD.p"F(]  
z8mR< q%`  
>GgX-SZ%  
//读取保存的下载信息（文件指针位置） )D@1V=9,  
private void read_nPos() BJk\p.BVN  
{ 6A/Nlk.  
try{ NwuME/C7#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $d!Sl a  
int nCount = input.readInt(); 7Z"mVh}  
nStartPos = new long[nCount]; ![:S~x1  
nEndPos = new long[nCount]; +?(2-RBd  
for(int i=0;i<nStartPos.length;i++) n4ce)N@  
{ ;vF8V`f  
nStartPos = input.readLong(); "a6 wd  
nEndPos = input.readLong(); lbgnO s,  
} >3X!c"#l  
input.close(); %dS7u$Rnh  
} (ZjIwA9>  
catch(IOException e){e.printStackTrace ();} JQE^ bcr  
catch(Exception e){e.printStackTrace ();} .7Ys@;>B  
} o'%F*>#v  
C&3#'/&  
$[[6N0}*:  
private void processErrorCode(int nErrorCode) or~o'  
{ B.K"1o  
System.err.println("Error Code : " + nErrorCode); qw0tw2|  
} z(>{"t<C  
#v')iR"  
{`KgyCW:  
//停止文件下载 ^Q4w<sX'  
public void siteStop() ||}|=Sz  
{ $ah, $B  
bStop = true; 1?)<*[  
for(int i=0;i<nStartPos.length;i++) I1&Z@[  
fileSplitterFetch.splitterStop(); McxJ C<  
_W]2~9  
.?_wcp=  
} bu%@1:l  
} o]}b#U8S  
//负责部分文件的抓取 pt(GpbtWK  
**FileSplitterFetch.java ()(@Qcc  
*/ C1|e1  
package NetFox; _1dG!!L_  
fmA&1u/xMs  
,^,Vq]$3  
import java.io.*; Fx0K.Q2Y0  
import java.net.*; 8b(UqyV  
nPfVZG
t  
<hdR:k@#  
public class FileSplitterFetch extends Thread { I4  Tc&b  
)wpBxJ;dB}  
/+sn-$/"i  
String sURL; //File URL iyu%o9_0  
long nStartPos; //File Snippet Start Position 7-w +/fv  
long nEndPos; //File Snippet End Position f&ZxG,]Hi  
int nThreadID; //Thread's ID >('L2]4\v  
boolean bDownOver = false; //Downing is over X5qU>'?`  
boolean bStop = false; //Stop identical wv ,F>5P  
FileAccessI fileAccessI = null; //File Access interface AT+|}B!  
eOD;@4lR  
}9:\#  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException }&rf'E9  
{ 8:$kFy\A'  
this.sURL = sURL; Q2^}NQO=  
this.nStartPos = nStart; E`XUK,b  
this.nEndPos = nEnd; 3l`yy])t  
nThreadID = id; *0l^/jqn:  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~{Tus.jk  
} 0FjSa\ZH  
zEF3B  
1
5uVvp/  
public void run() qp  
{ =35EG{W(  
while(nStartPos < nEndPos && !bStop) #TZYe4#f  
{ z.]t_`KuF9  
HG=!#-$9  
VV?+q)  
try{ '8i np[_  
URL url = new URL(sURL); \0(QO8.
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,, ]y 8P  
httpConnection.setRequestProperty("User-Agent","NetFox"); tV*g1)'zX  
String sProperty = "bytes="+nStartPos+"-"; }.o rfW  
httpConnection.setRequestProperty("RANGE",sProperty); zL3~,z/o  
Utility.log(sProperty); (LTm!"Q  

U&wVe$  
u+[ZWhKUp  
InputStream input = httpConnection.getInputStream(); rA8neO)  
//logResponseHead(httpConnection); = Yh>5A  
}3lM+]pf  
m{_\@'q  
byte[] b = new byte[1024]; 4zpprh+`K  
int nRead; }v0oFY$u`H  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) c(ZkK  
{ ( y2%G=.j  
nStartPos += fileAccessI.write(b,0,nRead); B:qZh$YN  
//if(nThreadID == 1) }n:'@}  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); b,KQG|k  
} T9RR. ng  
Tp)-L0kD_k  
YmB z$  
Utility.log("Thread " + nThreadID + " is over!"); FFR_1Vf  
bDownOver = true; bzk@6jR1  
//nPos = fileAccessI.write (b,0,nRead); 1xL2f&bG  
} RQ9fA1YP  
catch(Exception e){e.printStackTrace ();} ?%;7k'0"  
} %Ni)^   
} i?qS8h{  
{\;CGoN|  
Gow_
a'  
//打印回应的头信息 *vCJTz  
public void logResponseHead(HttpURLConnection con) E:&=A 4%  
{ .FqbX5\p,  
for(int i=1;;i++) iW-w?!>|m  
{ 2[r#y1ro  
String header=con.getHeaderFieldKey(i); k U*
\Fa*E  
if(header!=null) d=xU f`^  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); O6Xu/X]  
Utility.log(header+" : "+con.getHeaderField(header)); 4}W*
,&_  
else #&1mc_`/  
break; 4@/
[aFH  
} h[ba$S,T  
} z1T.\mzfX  
$w)y
Q %  
5mnIQ~psR  
public void splitterStop() E2LpQNvN%g  
{ <[8at6;  
bStop = true; jGb+bN5U7  
} qI^6}PB  
.N5}JUj  
5``/exG>  
} ,Tvk&<!0  
Dx4?
6  
*-3K],^a  
/* flR6^6E  
**FileAccess.java qg'RD]a>R  
*//文件访问(定位，写) ~>k<I:BtrT  
package NetFox; 9,`WQ+OI  
import java.io.*; %%G2w63M  
A%k@75V@  
;} Ty b  
public class FileAccessI implements Serializable{ g9<*+fV 2$  
U$# ?Lw  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 TlQ#0_as[  
RandomAccessFile oSavedFile; Xb?P'nD  
long nPos; wta\C{{  
?Z.p.v  
aVNRhnM  
public FileAccessI() throws IOException *q=pv8&*s  
{ |k^'}n  
this("",0); eL0U5>#  
} }NMA($@A  
DJS0;!# |O  
pTprU)sa7  
public FileAccessI(String sName,long nPos) throws IOException [_G_Wl'#8  
{ pBL,kqYNA>  
oSavedFile = new RandomAccessFile(sName,"rw"); ^QpP'  
this.nPos = nPos; 2
h IM!wQ  
oSavedFile.seek(nPos); Uk`ym  
} ;8'hvc3i$  
B~D{p t3y  
/[q6"R!uMz  
public synchronized int write(byte[] b,int nStart,int nLen) z{]$WVs:^  
{ CJ8XKy  
int n = -1; #@w8wCj  
try{ +j1s*}8  
oSavedFile.write(b,nStart,nLen); VY<$~9a&1  
n = nLen; 58DkVQ6  
} Zz!XH8sH  
catch(IOException e) O6pswMhAc  
{ }JeG
jpAcV  
e.printStackTrace (); ]e$mTRi*  
} M/EEoK^K@  
)iNMjg  
9s>q4_D  
return n; WldlN?[j  
} }rj

.N98  
B:\\aOEj  
Pv17wUB  
} Aq yR+  
P(l$5x]g,  
O:IU|INq8  
/* ai)S:2  
**SiteInfoBean.java f*,jhJ_I  
*/ uUB,OmLN  
package NetFox; v*Ds:1"H-I  
4w
\ r `@  
?3D|{  
public class SiteInfoBean { -*~= 4m<  
Dt%Gv0  
\T`InBbf  
private String sSiteURL; //Site's URL wN>k&J  
private String sFilePath; //Saved File's Path 
k
|k  
private String sFileName; //Saved File's Name [CL.Xil=  
private int nSplitter; //Count of Splited Downloading File Hbu8gqu  
m2F2  
2&MIt(\-  
public SiteInfoBean() Y,w'Op  
{//nSplitter的缺省值为5 UbNA|`H  
//default value of nSplitter is 5 jfP2n5X83  
this("","","",5); &_Ze@Ir-  
} mk(O..)2  
4y\qJw)~U  
W/!M eTU&E  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) R4"*<%1  
{ @}eEV[Lli  
sSiteURL= sURL; +;^UxW  
sFilePath = sPath; xP#vAR  
sFileName = sName; m5m}RWZ#  
this.nSplitter = nSpiltter; B>Tfyo  
UF0W%Z  
O=~8+sa  
} ZKy)
F-yX  
s~ ||Vv!  
nr7#}pzo  
public String getSSiteURL() Yv<'QC  
{ ]L+YnZ?6  
return sSiteURL; F*m^AFjs  
} QK%Nt
 
5$f vI#NO<  
Uc%n{ a-a  
public void setSSiteURL(String value) ,5!&}  
{ +`tl<rg;  
sSiteURL = value; i[_(0P+Da  
} %J(y2 }  
f++MH]I;  
p)6!GdT  
public String getSFilePath()
R= ,jqW<  
{ Z6s-n$dSm  
return sFilePath; w0qrh\3du  
} `EKmp|B_p_  
G&,1 NjSi  
b3R1L|@  
public void setSFilePath(String value) ,;;7+|`  
{ NwAvxN<R(f  
sFilePath = value; jf&B5>-x  
} 9{[I|  
TL&`Ywy  
Vw-,G7v&E  
public String getSFileName() z=mH\!  
{ ?*DM|hzOi  
return sFileName; [v47_ 5O  
} q^!_jMN5  
O2i7w1t  
f>*T0"\c  
public void setSFileName(String value) #b~B 0:U  
{ -55[3=#

 
sFileName = value; Lx%*IE|c
 
} #1Zqq([@  
T_t5Tg~i[N  
di.yh3N$  
public int getNSplitter() -R%T Dx  
{ 9mE6Cp.Wv  
return nSplitter; LS
ewMj  
} pK`1pfih  
WX"iDz.  
#(@!:f1  
public void setNSplitter(int nCount) z$g cK>@l  
{ y;Ez|MS   
nSplitter = nCount; @*?)S{8  
} 6HroKu  
} 9S'u1%  
6U.A/8z  
OaTnQ|*  
/* `iHyGfm  
**Utility.java @JW HG1qJ  
*/ $4>(}  
package NetFox; k1lo{jw`  
,LE
15},  
vCvjb\S  
public class Utility { ML_$/  
ATQw=w 3W  

B
orr  
public Utility() TWzlF>4N  
{ J`6
IH#54  
F u>  
vYFtw L`  
} @%lkRU)  
gB _/(  
//线程睡眠 1JQ5bB"  
public static void sleep(int nSecond) kM6i{{Q  
{ J#.f%V
J  
try{ Ky0}phGRu  
Thread.sleep(nSecond); 2xLEB&  
} ^VC/tJ  
catch(Exception e)
# &,W x  
{ 1NAGGr00  
e.printStackTrace (); Fqt,VED  
} jJY{np  
} w"`Zf7a{/  
Z8Iqgz7|y  
//日志 v)p'0F#6A  
public static void log(String sMsg) !dQmg'_V  
{ nx
Wm  
System.err.println(sMsg); ~<N9ckK  
} =K)[3mXX  
{EfA#{x  
QdIx@[+WOq  
public static void log(int sMsg) _sb~eB~<(  
{ i:a*6b.U@N  
System.err.println(sMsg); zif&;)wV/  
} c"O4=[N: ;  
} a(J@]X>'  
@m5c<(bkfp  
N \~}`({  
/* ')
Q  
**TestMethod.java c@
E;v<r'  
*/ MzFFWk  
package NetFox; DsB30  
57fl<IM  
4wMZNa<S
x  
public class TestMethod { y Nc@K|  
?gsPHPUS  
j.&Y'C7GOC  
public TestMethod() o%b6"_~%3  
{ ///xx/weblogic60b2_win.exe bm*.*A]  
try{ &6^ --cc  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); oVTXn=cYDp  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); S$O5jX 0  
SiteFileFetch fileFetch = new SiteFileFetch(bean); L6?~<#-m\M  
fileFetch.start(); 7|HIl=  
} YQ$LU\:  
catch(Exception e){e.printStackTrace ();} m#$$xG  
?8w5tfN6t  
`h|Y0x  
}
>\!G43Q=  
/Rf,Rjs  
(@1>G ^%  
public static void main(String[] args) CnpQdI  
{ fsl ZJE  
new TestMethod(); ~.tl7wKkR/  
} \.aKxj5
  
} 4tEAi4H|`@  
点击下载更多相关资料