http断点续传简单实现（java)

/* K)NB{8 _  
**SiteFileFetch.java P#e1?  
*/ {NmpTb  
package NetFox; <cC0l-=  
import java.io.*; Djv0]Sm^!  
import java.net.*; iWCR5c=  
BS-nny
  
w[`2t{^j  
public class SiteFileFetch extends Thread { Po+I!TL'  
#<_gY  
sK1YmB :~a  
SiteInfoBean siteInfoBean = null; //文件信息Bean oWCy%76@  
long[] nStartPos; //开始位置 4sU*UePr  
long[] nEndPos; //结束位置 j?!BHNs  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~Sq!P  
long nFileLength; //文件长度  :{#%_^}k  
boolean bFirst = true; //是否第一次取文件 \}CQo0v  
boolean bStop = false; //停止标志 cJb.@8^J  
File tmpFile; //文件下载的临时信息 <P)U Ggd  
DataOutputStream output; //输出到文件的输出流 8GRp1'\Hi  
jC<1bf$K  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） syuW>Z8s
  
public SiteFileFetch(SiteInfoBean bean) throws IOException 2'R;z<_  
{ ?-'m#5i"  
siteInfoBean = bean; /-Saz29f^Q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); FE}!I  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >j5,Z]  
if(tmpFile.exists ()) jg2UX  
{ 93Z/|7  
bFirst = false; m 2tw[6M  
read_nPos(); PKDzIA~T  
} d4y?2p ?3  
else
5U%J,W  
{ b=V"$(Q  
nStartPos = new long[bean.getNSplitter()]; ,7` /D  
nEndPos = new long[bean.getNSplitter()]; !Q-h#']~L  
} j=raS  
f
W/G_  
ixK&E#  
XUI9)Ne  
} $-HP5Kj(k-  
yr4j  
jO` b&]0  
public void run() ;3 N0)  
{ r>!$eqX_  
//获得文件长度 _G$SA-W(  
//分割文件 pN\YAc*@:  
//实例FileSplitterFetch hLs<g!*O  
//启动FileSplitterFetch线程 x2q6y  
//等待子线程返回 $0uh8RB  
try{ "c0I2wq  
if(bFirst) Uavr>-  
{ Z*AT &7  
nFileLength = getFileSize(); GM1z@i\5  
if(nFileLength == -1) }}R?pU_  
{ )@vhqVv?  
System.err.println("File Length is not known!"); &sFEe<  
} li!3bv  
else if(nFileLength == -2) iD;pXE{2s%  
{ [C8lMEV~  
System.err.println("File is not access!"); %kS4v,
I  
} =rw60B  
else =H<I` J'  
{ *=sMJY9#jE  
for(int i=0;i<nStartPos.length;i++) x,U'!F  
{ 0_!')+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 4trP*u,4  
} tHh
au.!  
for(int i=0;i<nEndPos.length-1;i++) s} I8:ufT  
{ W0zRV9"P  
nEndPos = nStartPos[i+1]; ]xx}\k  
} F&tU^(7<  
nEndPos[nEndPos.length-1] = nFileLength; iy<|<*s2D  
} (-<s[VnXP  
}  U(d K  
.Y
w  
L|?$F*bs  
//启动子线程 "aU) [  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :.k1="H~@  
for(int i=0;i<nStartPos.length;i++) `u<\ 4&W  
{ 1*x;jO>Hk  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?S*Cvr+=4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), bv&#ay7  
nStartPos,nEndPos,i); Nldy76|g  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;S&PLgZ  
fileSplitterFetch.start(); s6U$]9 `  
} '-,$@l#  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /?ZO-]q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Qkvg85  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", YaBZ#$r  
nEndPos = " + nFileLength); Gu#Vc.e  
// fileSplitterFetch[nPos.length-1].start(); 3R}O3#l
j,  
y[D8rFw  
Q[vQT?J7  
//等待子线程结束 Y94^mt-  
//int count = 0; X7bS{GT  
//是否结束while循环 ?Z0NHy;5  
boolean breakWhile = false; \80W?9qj  
r_x|2 AoO  
~E8
L,h~  
while(!bStop) #JAy  
{ eP?=tUB!S  
write_nPos(); ir{li?kV  
Utility.sleep(500); 
?W3l  
breakWhile = true; mTj?W$+r  
H@'f=Y*D  


&Hi;>  
for(int i=0;i<nStartPos.length;i++) %W(/W9B$/F  
{ -MK9IO]i  
if(!fileSplitterFetch.bDownOver) f?qp*  
{ {^T_m)|n  
breakWhile = false; j;MQ_?"iN  
break; L0Ycf|[s,  
} +W%3VV$  
} %tE#%;Z  
if(breakWhile) 4:I'zR5  
break; ^pysoaZCT_  
svaclkT=  
nI es}n:  
//count++; TwI'}J|w  
//if(count>4) F"ua`ercI  
// siteStop(); n^t!+  
} D}MCVNd^  
lEYAq'=  
S;8gX1Uf  
System.err.println("文件下载结束！"); W]CsKN,K  
} ~Z>!SMXp<  
catch(Exception e){e.printStackTrace ();} 6Mj
(B*c  
} Z1y=L$t8  
.N>Th/K8  
vTl7x  
//获得文件长度 W\pO`FL  
public long getFileSize() m<e_Z~^G  
{ ~PtIq.BY  
int nFileLength = -1; @2;/-,4O  
try{ fP KFU  
URL url = new URL(siteInfoBean.getSSiteURL()); bzWWW^kNL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); k9_c<TSzu  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ncr*F^J4  
YAsE,M+  
=j~v
L`d2]  
int responseCode=httpConnection.getResponseCode(); a/{M2  
if(responseCode>=400) VR XK/dZ  
{ |[W7&@hF  
processErrorCode(responseCode); ccY! OSae  
return -2; //-2 represent access is error :Ldx^UO  
} 0@tN3u?dx  
P#l"`C /  
MJM<  
String sHeader; *~\R0ddz  
[e`e bn[C  
u Wxl\+_i  
for(int i=1;;i++) M~ku4ZP  
{ NiSH$MJ_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [vTk*#Cl4  
//Utility.log(in.readLine()); ~wFiq)v(  
sHeader=httpConnection.getHeaderFieldKey(i); iF*L-  
if(sHeader!=null) J|aU}Z
8m  
{ *hIjVKTu79  
if(sHeader.equals("Content-Length")) V%Ww;Ca]I  
{ :[J'B4>9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); mv{bX|.  
break; sKwUY{u\M  
} [:(hqi!  
} T&nIH[}v  
else E0)43  
break; D$U`u[qjtS  
} Pk{%2\%&2  
} d#CAP9n;
'  
catch(IOException e){e.printStackTrace ();} ^N&@7s  
catch(Exception e){e.printStackTrace ();}
X]4j&QB  
]S 3l' "  
 \RS ,Y  
Utility.log(nFileLength); t`")Re_j  
eXAJ%^iD  
Q#5~"C  
return nFileLength; 0^83:C ^{  
} \h@3dJ4  
rK[;wD<  
tUk)S  
//保存下载信息（文件指针位置） Bp-e< :  
private void write_nPos() dT7!+)s5-  
{ hEq-)-^G  
try{ -oT3`d3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ~0Z.,p_  
output.writeInt(nStartPos.length);
KA? J:  
for(int i=0;i<nStartPos.length;i++) lw43|_'G-t  
{ %j/}e>$"Nk  
// output.writeLong(nPos); dwqR,|  
output.writeLong(fileSplitterFetch.nStartPos); \IP 9EFA  
output.writeLong(fileSplitterFetch.nEndPos); uH |
:gF^  
} P?h
B`5X  
output.close(); %W^Zob  
} ?k^~qlye  
catch(IOException e){e.printStackTrace ();} ?UV|m  
catch(Exception e){e.printStackTrace ();} b

;>?m  
} ML.|\:r*  
Nj{;  
0{(5J,/BF  
//读取保存的下载信息（文件指针位置） oTg 'N  
private void read_nPos() dC>(UDC  
{ ,Bs/.htQj  
try{ tz9"#=}0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); tu's]3RE  
int nCount = input.readInt(); 4hx4/5[^  
nStartPos = new long[nCount]; 6w4HJZF~  
nEndPos = new long[nCount]; 'Pe;Tp>`  
for(int i=0;i<nStartPos.length;i++) no(or5UJ  
{ ldnKV&N  
nStartPos = input.readLong(); :3[;9xCHj  
nEndPos = input.readLong();  }=d}q *  
} k\X yR4r  
input.close(); 8RT<?I^5  
} Gdz*  
catch(IOException e){e.printStackTrace ();} [P`<y#J3F  
catch(Exception e){e.printStackTrace ();} zvn3i5z  
} >U)>~SQf  
P~;1adi3  
~3)d?{5  
private void processErrorCode(int nErrorCode) ~;}uYJ  
{ "fC>]iA8I  
System.err.println("Error Code : " + nErrorCode); I2
WWhsNC  
} 1<Vke$  
$IqubC>O  
:{9HsF"h0  
//停止文件下载 ]Pe8G(E!  
public void siteStop() )jj
L'  
{ *|ef#-|D  
bStop = true; 1&RB=7.h
 
for(int i=0;i<nStartPos.length;i++) ioUO0  
fileSplitterFetch.splitterStop(); P4:Zy;$v!  
FXul u6"SX  
Fl!D2jnN  
} &88c@Ksn  
} 2U3e!V  
//负责部分文件的抓取 C]&/k_k  
**FileSplitterFetch.java ?)H:.]7-x  
*/ Sd/7#  
package NetFox; 85USMPF  
*D67&/g.  
.hJcK/m  
import java.io.*; ]&s@5<S[  
import java.net.*; (Q=:ln;kM  
<cO `jK  
M)~sL1)  
public class FileSplitterFetch extends Thread { -O\fy!  
BO2s(8  
R$`%<Y3)  
String sURL; //File URL xDNXI01o  
long nStartPos; //File Snippet Start Position R'pfA B|!  
long nEndPos; //File Snippet End Position M+I9k;N6&  
int nThreadID; //Thread's ID ,/&|:PkS  
boolean bDownOver = false; //Downing is over JNo[<SZb  
boolean bStop = false; //Stop identical sR^b_/ElxT  
FileAccessI fileAccessI = null; //File Access interface t'Zv)Wu1E  
]Upr<!  
Bus]OF>hu  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4dy!2KZN  
{ P`avn  
this.sURL = sURL; -qBdcbi|x)  
this.nStartPos = nStart; aQ-SrxmO8  
this.nEndPos = nEnd; > Edsanx  
nThreadID = id; 86>@.:d  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 sN K^.0  
} r4d#;S9{o  
{|'NpV  
M9G?^mW1sT  
public void run() %K,cGgp^)  
{ 4I9Yr
 
while(nStartPos < nEndPos && !bStop) 2Bi?^kQ#  
{ @?RaU4e  
u@tH6k*cBz  
-hq^';,  
try{ ?dXAHY  
URL url = new URL(sURL); .[+}nA,g%~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `KZu/r-M9  
httpConnection.setRequestProperty("User-Agent","NetFox"); K'B*D*w  
String sProperty = "bytes="+nStartPos+"-"; _GM?`  
httpConnection.setRequestProperty("RANGE",sProperty);  > H&v  
Utility.log(sProperty); P 5.@LN  
MS:,I?  
Dp4x\97O  
InputStream input = httpConnection.getInputStream(); Bw~jqDZ}|  
//logResponseHead(httpConnection); L9oLdWa(C  
6&QOC9JW+7  
x4h.WDT$  
byte[] b = new byte[1024]; Gqj(2.AY  
int nRead; 4Dy1M}7
 
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @R<z=n"  
{ /ZM xVh0  
nStartPos += fileAccessI.write(b,0,nRead); 9m)gp19YA  
//if(nThreadID == 1) LG:d  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6"NtVfui  
} X(BX+)YR  
eeBW~_W  
gW<4E=fl  
Utility.log("Thread " + nThreadID + " is over!"); 5$Kd<ky  
bDownOver = true; OT(0~,.GJ  
//nPos = fileAccessI.write (b,0,nRead); y}is=h3  
} u8t|!pMF8  
catch(Exception e){e.printStackTrace ();} Mp=T;Nz  
} p+5J  
} p]<)6sZ  
T]/5aA4  
VLVDi>0i  
//打印回应的头信息 5<e{)$C  
public void logResponseHead(HttpURLConnection con)  U ^nv)  
{ /r2S1"(q  
for(int i=1;;i++) !D?(}nag  
{ YQtq?&0Ct  
String header=con.getHeaderFieldKey(i); ]')y(_{  
if(header!=null) %YbL%i|U  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); mnBTZ/ZjS  
Utility.log(header+" : "+con.getHeaderField(header)); }%AfZ2g;h  
else A6J:!sY4A  
break; -ssmj8:Q\|  
} >&ZlCE  
} `7'^y  
2h#.:!/SMw  
T1R~^x1  
public void splitterStop() ~]].i~EV(  
{ OnhR`  
bStop = true; ]*gf$D  
} q/
Vl>t  
^)GaVL^"5  
fUfd5W1"  
} aOd|;Z  
KJv%t_4'F  
`(gQw~|z  
/* cK2;)
&U7  
**FileAccess.java Ux{0)"fj  
*//文件访问(定位，写) 3)L#V .  
package NetFox; =CD.pw)B1
 
import java.io.*; ! 2knSS  
M,X)rM}Q  
pQ!lY  
public class FileAccessI implements Serializable{ ~:PM_o*6  
oO`a{n-  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 4)>UTMF  
RandomAccessFile oSavedFile; %Ofw"W  
long nPos; .t8hTlV?<B  
/I1n${{5  
w<zzS:PF*  
public FileAccessI() throws IOException ,qo^G0XO  
{ mXS"nd30bD  
this("",0); R'6(eA[K  
} mlLqQ<  
'n1$Y%t  
.{ZJywE<  
public FileAccessI(String sName,long nPos) throws IOException J7C?
Z  
{ HG< z,gE 2  
oSavedFile = new RandomAccessFile(sName,"rw"); -T i<H9OV  
this.nPos = nPos; C9!FnvH
 
oSavedFile.seek(nPos); `p1B58deC  
} k Jw Pd;%  
Q+wO\TtE  
J]w3iYK  
public synchronized int write(byte[] b,int nStart,int nLen) )siWc_Z4  
{ lkly2|wA  
int n = -1; BlZB8KI~  
try{ ~c] q:pU2  
oSavedFile.write(b,nStart,nLen); jIwN,H1$-  
n = nLen; ){z#Y#]dP  
} tw=A] a*  
catch(IOException e) k.2GIc:5  
{ 9;uH}j8sE  
e.printStackTrace (); ),y`Iw  
} 8~y
P?#p  
UjLq[,_!  
BOR$R}q  
return n; g kV`ZT9  
} K"|~D0Qgo  
#_`p 0wY  

^$C&{%  
} :VWN/m  
MK@rx6<9  
j
JNl{nyq  
/* 3TLym&  
**SiteInfoBean.java J]zhwM  
*/ @o*~\E<T  
package NetFox; M(:bM1AD`u  
:SW vH-]  
CB,2BTtRE  
public class SiteInfoBean { TQ:e! 32  
KaS*LDzw  
PC+Soh*  
private String sSiteURL; //Site's URL ?Q+*[YEJ5  
private String sFilePath; //Saved File's Path KKb7dZbt<  
private String sFileName; //Saved File's Name zY@0R`{@p  
private int nSplitter; //Count of Splited Downloading File NS""][#  
.Ln98#ZR  
64'QTF{D  
public SiteInfoBean() =
qoOr~  
{//nSplitter的缺省值为5 ;($xAAR  
//default value of nSplitter is 5 9z{g3m70@  
this("","","",5); tS5J{j>T  
} #G?#ot2o  
f*88k='\W  
(UhJ Pco"  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }
EHL }Q  
{ BzH0"xq^  
sSiteURL= sURL; _TmKn!Jw  
sFilePath = sPath; 0_-o]BY  
sFileName = sName; iR PE0  
this.nSplitter = nSpiltter; @%*@Rar  

n%RaEL  
>?)_, KL  
} YU`k^a7%  
"VHT5k  
~`^kP.()  
public String getSSiteURL() BB9eQ: xO  
{ $cuBd  
return sSiteURL; Vr"'O
6  
} ^+-]V9?+  
[{#TN  
_ W#Km  
public void setSSiteURL(String value) &iq'V*+-\  
{ WA1yA*S  
sSiteURL = value; \ZhkOl  
} 0S4Y3bac&  
n[qnrk*3 %  
5D?{dA:Rq  
public String getSFilePath() $I/ !vV  
{ c+7I  
return sFilePath; d8R|0RZ  
} #*lDKn[vO  
q[W@.[2y)  
d2US~.;>l  
public void setSFilePath(String value) 7QZyd-  
{ xXI WEZA  
sFilePath = value; 5 8L@:>"  
} |; mET  
&e3}Vop  
yw%ES  
public String getSFileName() L0H^S)g  
{ '/Vm[L$d  
return sFileName; ;"e55|d9I  
} b"}ya/  
IG;= |  
Oml3=TV  
public void setSFileName(String value) [T)>RF  
{ >Wx9a"H^(  
sFileName = value; Q>;Aq!mr=  
} W>Pcj EI  
4T"L#o1  
V4CA*FEA  
public int getNSplitter() D'{o3Q,%K  
{ nygeR|:\  
return nSplitter; vl}}h%BC  
} Xkx&'/QG,U  
pNuU{:9 B0  
nehk8+eV_  
public void setNSplitter(int nCount) 2$b1q!g<  
{ n!~QC  
nSplitter = nCount; 0R+p\Nc&1  
} wt'"<UN  
} ){u# (sW  
[I'q"yRu]i  
1|G5 W:  
/* p
14$XV  
**Utility.java k%-UW%  
*/ H15!QxD#  
package NetFox; &`>dY /Y  
p<Tg}fg  
GMLx$?=j  
public class Utility { 
\>w 2D  
<; Td8O89_  
?
;(
!(<{  
public Utility() JJM!pD\h  
{ $Op:-aW&  
8Jp?@qt=$  
$(OL#>9Ly  
} G%i&C)jZ  
~"wnlG-:  
//线程睡眠 @^-f+o  
public static void sleep(int nSecond) }095U(@  
{ ov\%*z2=  
try{ 673G6Nk  
Thread.sleep(nSecond); :'fK`G 6  
} ,y/
m5-D!  
catch(Exception e) &@2`_%QtA  
{ :,/ \E  
e.printStackTrace (); sv "GX<+  
} g&ba]?[A  
} ^Ga_wJP8S  
RJN LcIm  
//日志 o@} qPvt0  
public static void log(String sMsg) HC>k/Gk"  
{
4`r-*Lx  
System.err.println(sMsg); ashVV
~\8A  
} 91T[@p  
eD^(*a>(  
F:0 E- z'  
public static void log(int sMsg) (~b0-3s  
{ jt9@aN.mJN  
System.err.println(sMsg); OQyZ'  
} 3A\Hiy!{F  
} %
6@m~;c0  
pf=CP%L  
{gDoktC@M  
/* ^*~4[?]S  
**TestMethod.java ?DNeL;6  
*/ &,]yqG 2  
package NetFox; Aj>  
)hK;27m4  
UC00zW<Z@"  
public class TestMethod { 3+M+5  
f-}_  
>Y:veEa6v6  
public TestMethod() 9!D c=  
{ ///xx/weblogic60b2_win.exe :{Iv ]d  
try{ g
aL.5_1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); h#|Ac>fz  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); &23t/`
  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =VZ0+Yl  
fileFetch.start(); M3)Id?|]6  
} Vt4,?"  
catch(Exception e){e.printStackTrace ();} y#lg)nB  
w/CD-  
9v}vCg  
} fEyc3K'5V  
h&bs`  
^"$~&\+x5  
public static void main(String[] args) ;,u7)  
{ x&FBh!5H  
new TestMethod(); <L3ig%#B  
} 1|3vwgRhs  
} F;Ubdxwwl  
点击下载更多相关资料