http断点续传简单实现（java)

/* ^t71${w##  
**SiteFileFetch.java o3\^9-jmp  
*/ f3n^Sw&Q(Q  
package NetFox; ?./fVoA]V  
import java.io.*; 1u5^a^O(|  
import java.net.*; ]K8G}|Wy6  
IY6Qd4157  
(w2lVL&  
public class SiteFileFetch extends Thread { %scIZCrI~  
mXhC-8P  
A@?-
"=h}  
SiteInfoBean siteInfoBean = null; //文件信息Bean ns~bz-n  
long[] nStartPos; //开始位置 rQNm2h  
long[] nEndPos; //结束位置 AxH`4=3<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 BMQ4i&kF|  
long nFileLength; //文件长度 J=8Y D"1  
boolean bFirst = true; //是否第一次取文件 oiR9NB&<  
boolean bStop = false; //停止标志 5M9o(Z\AF  
File tmpFile; //文件下载的临时信息 YahW%mv`d  
DataOutputStream output; //输出到文件的输出流 T`j{2  
55TFBDc  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） pO fw *lD  
public SiteFileFetch(SiteInfoBean bean) throws IOException Het>G{  
{ 6C<GYzzo  
siteInfoBean = bean; %XBTN  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); N"RPCd_  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); a
%a0/!U[  
if(tmpFile.exists ()) b;*'j9ly  
{ <Piq?&VX[  
bFirst = false; ZybfqBTD&c  
read_nPos(); v5e*R8/  
} TG8U=9qt  
else m5] a  
{ 6&6dd_K(  
nStartPos = new long[bean.getNSplitter()]; /E{tNd^S  
nEndPos = new long[bean.getNSplitter()]; YMNLn9  
} DzA'MX  
G(shZ=fq  
3G 5xIr6   

(RrC<5"  
} o(> #}[N}  
Z  eY*5m  
Ktt(l-e+  
public void run() )+Z.J]$O-  
{ b&QI#w  
//获得文件长度 yKK9b  
//分割文件 @].!}tz  
//实例FileSplitterFetch \kY:|T  
//启动FileSplitterFetch线程 z{PPPFk4J  
//等待子线程返回 }X=c|]6i^  
try{ #PPHxh*S  
if(bFirst) *wX[zO+o  
{ EBk-qd a}  
nFileLength = getFileSize(); y=+OC1k\8  
if(nFileLength == -1) 7@e}rh?N-|  
{ ;o;ak.dTt  
System.err.println("File Length is not known!"); [euR<i*I#  
} 9mn~57`y  
else if(nFileLength == -2) 1 |)
CQ  
{ l O*  
System.err.println("File is not access!"); /B 3\e3  
} l_9ZzN  
else =\oW{?  
{ 9C Ki$L  
for(int i=0;i<nStartPos.length;i++) ,JbP~2M~%  
{ m:
~y:.  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); .X)Wb{7  
} 5A5t
 
for(int i=0;i<nEndPos.length-1;i++) -#G>`T~  
{ _\,lv \u  
nEndPos = nStartPos[i+1]; [h&s<<# D  
} c=?6`m,"M  
nEndPos[nEndPos.length-1] = nFileLength; z?VjlA(X  
} YwZx{%
f  
} 2u5\t
p?8  
L:?Ew9Lf  
E;'{qp  
//启动子线程 *}Gys/\!S  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; S9nn^vsK  
for(int i=0;i<nStartPos.length;i++) UA]T7r@  
{ 1=9GV+`n  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }hm_Ws  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),  5 b,|6  
nStartPos,nEndPos,i); =|empv#  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #)48dW!n  
fileSplitterFetch.start(); n_Y7*3/b-o  
} 0Krh35R_)F  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @;y@Hf'Jv  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $
T66%wX  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", o /1+ }f  
nEndPos = " + nFileLength); =WZ9|
e  
// fileSplitterFetch[nPos.length-1].start(); j` * bz-  
-k2|`t _  
?|}qT05  
//等待子线程结束 7h41E#  
//int count = 0; ;l0%yg/}  
//是否结束while循环
T$<'ZC  
boolean breakWhile = false; #D?w,<_8,  
tu{paQ  
FzCXA=m  
while(!bStop) P\{s C6E  
{ hgDFhbHtd6  
write_nPos(); 9jx>&MnWs  
Utility.sleep(500); 9&C8c\Y  
breakWhile = true; I0x;rP  
]:T:cO0_n  
y@2"[fo3~  
for(int i=0;i<nStartPos.length;i++) %1{O  
{ ''!j:49  
if(!fileSplitterFetch.bDownOver) q@VIFmqY!  
{ {-]K!tWda  
breakWhile = false; ;p<BiC$b  
break; iyUnxqP  
} Vj8-[ww!  
} (
G$Q\>  
if(breakWhile) =,qY\@fq  
break; eOXu^M>:F  
:=!6w  
b KDD29  
//count++; 'gD./|Z0  
//if(count>4) []yIz1P=j  
// siteStop(); "WXUz  
} 3i4m!g5Z?  
pX!T; Re;  
QG L~??  
System.err.println("文件下载结束！"); SJ;{ Hg  
} \'('HFr,  
catch(Exception e){e.printStackTrace ();} ~d,$nZ"z  
} tO1k2<Z"Y&  
4 CiRh  
/!6 VP |  
//获得文件长度 ^u0y<kItX  
public long getFileSize() 42,dH
Ydt  
{ u%1JdEWZd  
int nFileLength = -1; `jhbKgR[  
try{ ~+Cl9:4T  
URL url = new URL(siteInfoBean.getSSiteURL()); rTJqw@]#WH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); IeA/<'Us  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ro<5c_k  
L>hLYIW  
};Df ><  
int responseCode=httpConnection.getResponseCode(); 7`)RBhGB  
if(responseCode>=400) 3|)cT1ej  
{ \S?-[v*{  
processErrorCode(responseCode); fT?m~W^  
return -2; //-2 represent access is error
> hGB o  
} w_~tY*IwB  
=1)9>=}  
asy:[r"  
String sHeader; zA$ f$J7\^  
1E4`&?  
GN5*  
for(int i=1;;i++) %=s2>vv9  
{ E6T=lwOZ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2pSp(@N3  
//Utility.log(in.readLine()); =0;njL(7;  
sHeader=httpConnection.getHeaderFieldKey(i); B7[#z{8'#  
if(sHeader!=null) U!BZsVx  
{ J5Q.v;  
if(sHeader.equals("Content-Length")) &Akw V-  
{ jSdC1,wR  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); @q@I(%_`  
break; <9$Pl%:  
} +I*a=qjq  
} u'T>Y1I  
else "dYT>w  
break; YETGq-  
} <@4V G
 
} ).Iifu|
ks  
catch(IOException e){e.printStackTrace ();} %Br1b6 V  
catch(Exception e){e.printStackTrace ();} {`>pigo  
OP_\V8=  
SF ^$p$mC  
Utility.log(nFileLength); @.G;dL.f{  
o62GEl25  
(5hUoDr!  
return nFileLength; C9FAX$$^(Y  
} <5h}\5#<j  
&&"+\^3  
?01ru5ys/o  
//保存下载信息（文件指针位置） +I:/8,&-x  
private void write_nPos() #a]\3X  
{ ;uZeYY?   
try{ !<X/_+G\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?fc<3q"  
output.writeInt(nStartPos.length); "/taatcH  
for(int i=0;i<nStartPos.length;i++) B~O<?@]d  
{ *N6sxFs  
// output.writeLong(nPos); P.^*K:5@  
output.writeLong(fileSplitterFetch.nStartPos); tpgD{BY^wJ  
output.writeLong(fileSplitterFetch.nEndPos); b`;&o^7gMO  
} g]?>6 %#rA  
output.close(); ,d^HAg^j  
} <<@F{B7h  
catch(IOException e){e.printStackTrace ();} /7.//klN  
catch(Exception e){e.printStackTrace ();} +*eVi3  
} <0Gk:NB,  
-xyY6bxL  
nVP|
{M  
//读取保存的下载信息（文件指针位置）
Udjn.D  
private void read_nPos() jG#
e%`'  
{ ^ZBTd5t#  
try{ PbV1FB_  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 4O{,oN~7  
int nCount = input.readInt(); F"23vG>3  
nStartPos = new long[nCount]; N~?#Qh|ZnU  
nEndPos = new long[nCount]; YCdtf7P=q  
for(int i=0;i<nStartPos.length;i++) Y|KT3  
{ z\WyL;  
nStartPos = input.readLong(); ZlcEeG  
nEndPos = input.readLong(); Tj6Czq=*%T  
} ZF<$6"4N  
input.close(); OU?.}qc<wE  
} UdpuQzV<4`  
catch(IOException e){e.printStackTrace ();} T*(mi{[T  
catch(Exception e){e.printStackTrace ();} G) 37?A)  
} rfh`;G5s  
_ZK*p+u%  
I%z,s{9p  
private void processErrorCode(int nErrorCode) $B]_^  
{ D|vck1C5,  
System.err.println("Error Code : " + nErrorCode); X LY>}r  
} 4i"fHVp8  
gmiLjI  
C+Wa(K  
//停止文件下载 lxR]Bh+  
public void siteStop() @)ls+}=Y  
{ _]0<G8|Rv  
bStop = true; hw B9N  
for(int i=0;i<nStartPos.length;i++) pqohLA  
fileSplitterFetch.splitterStop(); !bn=b>+  
&}#zG5eu  
&hM7y
7  
} 9!dG Xq  
} +z~bH!$2  
//负责部分文件的抓取 < 7*9b  
**FileSplitterFetch.java ;2gO(  
*/ "_+8z_  
package NetFox; 'W&ewZH_h  
\23m*3"W  
p@d_Ru  
import java.io.*; dvAz}3p0]  
import java.net.*; ^--8 cLB n  
VLbbn  
eyn-bw  
public class FileSplitterFetch extends Thread { Fgi;%  
!R[~Z7b6  
B@8lD\  
String sURL; //File URL c+##!_[9  
long nStartPos; //File Snippet Start Position DX/oHkLD'  
long nEndPos; //File Snippet End Position srS)"Jt  
int nThreadID; //Thread's ID zXIdup@  
boolean bDownOver = false; //Downing is over =8Z-ORW51  
boolean bStop = false; //Stop identical \[AJWyP  
FileAccessI fileAccessI = null; //File Access interface 
}E&:  
Q-yNw0V}F  
{m_y<  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException jq_ i&~S  
{ 9LSV^[QUH  
this.sURL = sURL; 6|4ID"  
this.nStartPos = nStart; IJ7wUZp"  
this.nEndPos = nEnd; Ir Y\Q)  
nThreadID = id; fY|[YPGO^  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \ #la8,+9  
} nJwP|P_  
Qs<L$"L1  
;B{oGy.  
public void run() y#/P||PM  
{
Q&w"!N  
while(nStartPos < nEndPos && !bStop) ?kF? ~\c  
{ ]\/"-Y#4Q  
3sl6$NKo  
\GZ|fmYn  
try{ \0FwxsL  
URL url = new URL(sURL); 8zho\
'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); VU+=b+B~m  
httpConnection.setRequestProperty("User-Agent","NetFox"); w8`B}Dr23  
String sProperty = "bytes="+nStartPos+"-"; mH)8A+us  
httpConnection.setRequestProperty("RANGE",sProperty); &<- S-e  
Utility.log(sProperty); UUGX@  
m!3D5z]n9  
bicbCC6kC  
InputStream input = httpConnection.getInputStream();  +&<k}Mz  
//logResponseHead(httpConnection); 7zowvE?#  
60WlC0Y~u  
2dDhO  
byte[] b = new byte[1024]; WwxV}?Cf+  
int nRead; @c).&7  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) UQbk%K2  
{ x4v&%d=M  
nStartPos += fileAccessI.write(b,0,nRead); lW
UQ
kS  
//if(nThreadID == 1) |*l^<==  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~
m[Gp;pL  
} 1yFIIj:^|  
=o'g5Be<F  
b)r;a5"<5  
Utility.log("Thread " + nThreadID + " is over!"); C(M?$s`  
bDownOver = true; 4P#4RB  
//nPos = fileAccessI.write (b,0,nRead); ;s+3#Py  
} Uz%ynH  
catch(Exception e){e.printStackTrace ();} Zu94dF
P  
} i9T<(sdK+  
} bEmzigN[  
zT93Sb  
.eyJ<b9  
//打印回应的头信息 f*VXg[&\\F  
public void logResponseHead(HttpURLConnection con) C 1)+^{7ef  
{ sj6LrE=1  
for(int i=1;;i++) Oc5f8uv  
{ U
U#tm  
String header=con.getHeaderFieldKey(i); VHvL:z  
if(header!=null) [p]UM;+  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +x<OyjY5?]  
Utility.log(header+" : "+con.getHeaderField(header)); L^K,YlNBR  
else bgkBgugZhX  
break; :m>Vp  
} PzustC|  
} BnaI30-  
 \+:`nz3m  
\ rKUPI\  
public void splitterStop() cg9*+]rc  
{ =)a%,H  
bStop = true; q#\B}'I{  
} +{#Z^y6&  
9_~9?5PU  
>:BgatyP
H  
} 
RMdU1
@  
j]aIJbi  
G3h"Eo?>g  
/* PH'n`
D
#  
**FileAccess.java XV,ce~ro[  
*//文件访问(定位，写) IYa(B+nB)  
package NetFox; e*d lGK3l  
import java.io.*; A+FQmLS  
~yA^6[a=  
{aUv>T"c  
public class FileAccessI implements Serializable{ We'=/!  
?a'EkZ.dB  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 SL +\{V2  
RandomAccessFile oSavedFile; ]Rxrt~ ZB  
long nPos;  `YO&  
6o*'Q8h  
]cWQ9  
public FileAccessI() throws IOException D%6
}x^`Qk  
{ (!Xb8rV0_  
this("",0); VFm)!'=I  
} KcW 5  
Q5_,`r`  
r$Ik*
R  
public FileAccessI(String sName,long nPos) throws IOException
_qh\  
{ <N3~X,ch  
oSavedFile = new RandomAccessFile(sName,"rw"); V}Oz!  O  
this.nPos = nPos; KIKIag#  
oSavedFile.seek(nPos); ^==Tv+T9U  
} JOs kf(  
{wO.nOB  
rd"!&i  
public synchronized int write(byte[] b,int nStart,int nLen) jHObWUX  
{ B[2t.d;h  
int n = -1; ce719n$   
try{ l_,6<wWp  
oSavedFile.write(b,nStart,nLen); i+lq:St  
n = nLen; ;ZkY[5  
} [jEA|rd~}  
catch(IOException e) qLw^Qxo  
{ -iFFXESVX  
e.printStackTrace (); *z_`$Y
  
} =5:kV/p  
ZVit]3hd  
~{N#JOY}Z  
return n; z]=Ks_7  
} NdRE,HWd?$  
q6x}\$mL  
:`0,f?cE  
} P]L%$!g  
8:uh0  
)QmmI[,tq  
/* gV*4{d`  
**SiteInfoBean.java -w'g0/fD  
*/ ::3[H$  
package NetFox; 4#I=n~8a  
{}=5uU2Tu  
^9YS dFH/  
public class SiteInfoBean { <,H/7Ba  
!#E-p?O.  
>xH?`I7;f  
private String sSiteURL; //Site's URL :R3&R CTZ  
private String sFilePath; //Saved File's Path #W8c)gkG9  
private String sFileName; //Saved File's Name f/Z-dM\e  
private int nSplitter; //Count of Splited Downloading File vq@"y%C4  
A.YK=_J  
dN){w _  
public SiteInfoBean() CurU6x1  
{//nSplitter的缺省值为5 ?Qts2kae#  
//default value of nSplitter is 5 W!TTfj   
this("","","",5); `}8)P#  
} '%YTMN@  
0t*PQ%  
Ad-_=a%  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) !L_xcov!Y  
{ s"8z q;)  
sSiteURL= sURL; )a+bH</'  
sFilePath = sPath; Qb;]4[3  
sFileName = sName; "kucFf f  
this.nSplitter = nSpiltter; 'z+Pa^)v  
v~p?YYOm<  
9>_VU"T  
} 8zwH^q[`r  
f,BJb+0  
]HRHF'4  
public String getSSiteURL() DvA#zX[  
{ P#;pQC  
return sSiteURL; kjSzuqB  
} -7EwZRS@9  
64:p 4
N  
3@<m/%  
public void setSSiteURL(String value) TETfRnm  
{ qzk]9`i1:  
sSiteURL = value; dO-Zj#%7z8  
} dtXtZ!g2  
s GrI%3[e"  
%H}M[_f  
public String getSFilePath() 9AD0|,g  
{ .0|_J|{  
return sFilePath; C?\HB#41  
} 9g
$fFO  
g](&H$g  
Af^9WJ  
public void setSFilePath(String value) >q&e.-qL  
{ h@s i)5"  
sFilePath = value; J,=^'K(  
} +ERuZc$3,  
paxZlA o  
#EH\Q%  
public String getSFileName() TI8EW  
{ 0bGQO&s [  
return sFileName; C{6m?6  
} 2J`LZS  
2[KHmdgtB  
UZgrSX {  
public void setSFileName(String value) V{rQ@7SE  
{ q?f-h<yRQ  
sFileName = value; -BsZw. 7P  
} Mv7tK l  
 ~"h V-3U  
O:dUzZR['  
public int getNSplitter() 7[}WvfN8#  
{ zaE!=-U  
return nSplitter; *mN8Qd  
} ;47=x1ji  
"&mwrjn"T  
HZ\=NDz  
public void setNSplitter(int nCount) +H!aE}
  
{ n|PW^kOE/  
nSplitter = nCount; 9|9/8a6A  
} YDEb MEMd/  
} *#'&a(hB!  
>SD?MW1E  
v\XO?UEJ2  
/* Xd&oERJj  
**Utility.java K%/g!t)  
*/ Ge76/T%{Q  
package NetFox; fqol-{F.V  
Ft>,  
BU^E68?G  
public class Utility { M/}i7oS]  
0LP>3"Sm  
r\} O{ZO  
public Utility() /(i~Hpp  
{ S'sI[?\x  
J!zL)u|  
o1Wf#Zq  
} G:MQ_tfr&  
|:d_IB@  
//线程睡眠 a#3,qp!  
public static void sleep(int nSecond) yLt>OA<X  
{ l+O\oD?-  
try{ ]Vf2Mn=]"  
Thread.sleep(nSecond); SLud}|f;o  
} 9cMMkOM J  
catch(Exception e) (HeIO  
{ :NWrbfz  
e.printStackTrace (); {d,^tG}  
} Km0P)Z  
} ?:RWHe.P  
c5{3  
//日志 SxM5'KQ  
public static void log(String sMsg) By0Zz  
{ $tebNiP  
System.err.println(sMsg); v1E(K09h2  
} JRw)~Tg @  
zZ])G
  
Uql7s:!,U  
public static void log(int sMsg) 'ExQG$t  
{ "ScY'<  
System.err.println(sMsg); vn96o]n  
} E~,Wpl}  
} <*$IZl6I  
&>hln<a>  
`mKK1x  
/* X!]p8Q y  
**TestMethod.java $yMNdBI[  
*/ ?w@KF%D
 
package NetFox; jiLt *>I  
Oxh.&  
97VS xhr  
public class TestMethod { 6x! q  
q.p
.y0  
>zv}59M  
public TestMethod() UC"_#!3  
{ ///xx/weblogic60b2_win.exe {s[,CUL
0  
try{ h/#s\>)T  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); X(K5>L>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); +/8KN  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Yo2n[  
fileFetch.start(); ~g;lVj,N'  
} 0S>U_#-  
catch(Exception e){e.printStackTrace ();} XO4rrAYvW  
u[coWaPsZ  
ldWr-  
} .^uYr^(|[  
xA"7a  
^g n7DiIPH  
public static void main(String[] args) u_ym=N57`  
{ -r6LndQs  
new TestMethod(); Jgf=yri  
} 
gz"I=9  
} JA^Y:@<{/  
点击下载更多相关资料