http断点续传简单实现（java)

/* jVWK0Zba  
**SiteFileFetch.java eGL<vX  
*/ (=u'sn:s  
package NetFox; 94/BG0  
import java.io.*; )8,|-o=  
import java.net.*; 7K;!iX<d  
@?kJ).  
#_JYh?  
public class SiteFileFetch extends Thread { )nfEQ)L;h}  
Am"(+>W21  
YcDe@Zuwn  
SiteInfoBean siteInfoBean = null; //文件信息Bean @S^ASDuQU7  
long[] nStartPos; //开始位置 {ci.V*:"  
long[] nEndPos; //结束位置 wTc)S6%7  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 j:,9%tg  
long nFileLength; //文件长度 91Z'  
boolean bFirst = true; //是否第一次取文件 Vzg=@A#  
boolean bStop = false; //停止标志 }m-"8\_D  
File tmpFile; //文件下载的临时信息 IG ~`i I  
DataOutputStream output; //输出到文件的输出流 -_N)E ))G  
;9a 6pz<  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） =QOg 6  
public SiteFileFetch(SiteInfoBean bean) throws IOException %*}Y6tl'|  
{ "ju'UOcS/  
siteInfoBean = bean; iE].&>w  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); F@YKFk+a  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); BuOgOYh9  
if(tmpFile.exists ()) Fhf<T`  
{ EGVM)ur  
bFirst = false; mtAE  
read_nPos(); ?C-Towo=i  
} Ib=x~za@n  
else qv*7K@  
{ @N@F,~[RR2  
nStartPos = new long[bean.getNSplitter()]; 3gEMRy*+  
nEndPos = new long[bean.getNSplitter()]; u]*0;-tz  
} % Zjdl  
<0P5 o|  
8\.b4FNJ  
Yk!/ow@.  
} 0RFRbi@n(  
nh+l78  
3uWkc3  
public void run() 4?\:{1X=  
{ 49H+(*@v@  
//获得文件长度 !69&Ld  
//分割文件 zi@]83SS#  
//实例FileSplitterFetch cVnJ^*Z  
//启动FileSplitterFetch线程 /]
^#b  
//等待子线程返回 GL$De,V  
try{ X{xBYZv4  
if(bFirst) #%0Bx3uM  
{ W~1~k{A  
nFileLength = getFileSize(); avQJPB)}Sb  
if(nFileLength == -1) ^x>Qf(b  
{ Z @ dC+0[=  
System.err.println("File Length is not known!"); , t5 '  
} hVUh0XeO  
else if(nFileLength == -2) ,f3pqi9|  
{ j$7|XM6  
System.err.println("File is not access!"); v=@TWEE  
} \y`+B*\i  
else 8.AR.o  
{ kRCQv-*  
for(int i=0;i<nStartPos.length;i++) !>
,m&O-x  
{ Z<[<n0o1  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); \JEXX4%  
} m,i,n9C->  
for(int i=0;i<nEndPos.length-1;i++) pKiZ)3U  
{ N["W Ir  
nEndPos = nStartPos[i+1]; nAIo{ F  
} s#~GH6/  
nEndPos[nEndPos.length-1] = nFileLength; YHk
cWz  
} E>'a,!QPv  
} c/N@zum,{  
"5R~(+~<@  
\MC-4Yz  
//启动子线程 q;g>t5]a  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ajR%c2G;  
for(int i=0;i<nStartPos.length;i++) V&8VwF^-  
{ Z>c3  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), lGwl1,=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), RqEH|EUZ  
nStartPos,nEndPos,i); ,mhQ"\
+C  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R'EUV0KX>Y  
fileSplitterFetch.start(); 7w,FX.=;cv  
} VVH.2&`I  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Unj.f>U  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); voP7"Dl[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", wN1niR'  
nEndPos = " + nFileLength); |8>3`w!  
// fileSplitterFetch[nPos.length-1].start(); [[PEa-992  
poGc a1  
!tfb*@{;'  
//等待子线程结束 IW 21T  
//int count = 0; U*Ge<(v$  
//是否结束while循环 m8'C_U^89  
boolean breakWhile = false; ];'v8
)Y  
\%PaceH  
1XM^8 .;  
while(!bStop) fkf1m:Ckh  
{ S}APQ  
write_nPos(); JD@J[YY5R  
Utility.sleep(500); 2 rw%H  
breakWhile = true; 1) ta  
BdlVabQyKW  
8Ac)'2t;U  
for(int i=0;i<nStartPos.length;i++) Bm&kkx.9P  
{ ~|<WHHN
(  
if(!fileSplitterFetch.bDownOver) \
fA{1  
{ ~
P~  
breakWhile = false; 2gO2jJlv  
break; MZ Aij  
} R|O8RlH  
} u[nyW3MZ  
if(breakWhile) dJT]/g  
break; %K(<$!  
pw7[y^[Qg  
@u==x*{|  
//count++; >2bK
Sh  
//if(count>4) PV|uPuz  
// siteStop(); ^Ge+~o?x  
} j'9"cE5_  
i4^o59}8  
#fT*]NN  
System.err.println("文件下载结束！"); m[j70jYe  
} nX$XL=6mJ&  
catch(Exception e){e.printStackTrace ();} w"R:\@ F  
} D8 hr?:I9  
!rqF}d  
,
-7R
(iMd  
//获得文件长度 =-_B:d;  
public long getFileSize() %f($*l.  
{ jqPkc28  
int nFileLength = -1; =bEda]  
try{ I\Y
V des#  
URL url = new URL(siteInfoBean.getSSiteURL()); w@
N  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h;6lK$!c  
httpConnection.setRequestProperty("User-Agent","NetFox"); y|'SXM  
}CeCc0M  
cA%%IL$R  
int responseCode=httpConnection.getResponseCode(); ]`Oo%$Ue  
if(responseCode>=400) M5xCC!  
{ 2W4qBaG$=  
processErrorCode(responseCode); JV;OGh>  
return -2; //-2 represent access is error ]T%rjsN  
} 6Cn+e.j@  
5nsq[Q`  
]Dw]p!@  
String sHeader; 6/rFHY2q  
^tXJj:
wtS  
6R=W}q4  
for(int i=1;;i++) Q+YRf3$  
{ 7b<yVP;{  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); D1__n6g[  
//Utility.log(in.readLine()); w8n|B?Sr  
sHeader=httpConnection.getHeaderFieldKey(i); )B[0JrcE  
if(sHeader!=null) P*cNh43U  
{ ;[fw]P n  
if(sHeader.equals("Content-Length")) s`0QA!G{-  
{ ki85!k=Q2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8']9$#  
break; D9z|VIw8  
} r#XT3qp$d  
} ?M[ A7?  
else qAw x2fPu  
break; fFc/ d(  
} wXsmn1w9  
} ~R(%D-k  
catch(IOException e){e.printStackTrace ();} )E~79!  
catch(Exception e){e.printStackTrace ();} eut-U/3:#  
l5"OIq  
V O3x~E  
Utility.log(nFileLength); 8QM
(?A  
q5?# 3T=  
JU4qzi  
return nFileLength; t+eVR8  
} l8?>>.<P=  
~JaA
ii{  
%Ah^E$&n2  
//保存下载信息（文件指针位置） y3h/IpT  
private void write_nPos() V3"=w&2]K  
{ 5=f|7yl  
try{ ELj\[&U  
output = new DataOutputStream(new FileOutputStream(tmpFile)); z_|/5$T>U  
output.writeInt(nStartPos.length); hNzB4p  
for(int i=0;i<nStartPos.length;i++) }`@728E  
{ E2m8UBS  
// output.writeLong(nPos); h=:Q-?n-  
output.writeLong(fileSplitterFetch.nStartPos); Y./2Ely  
output.writeLong(fileSplitterFetch.nEndPos); JfR%L q~  
} m}X`> aD/  
output.close(); 3\B>lKhQ  
} 2RX!V@z.G  
catch(IOException e){e.printStackTrace ();} /oriW;OF  
catch(Exception e){e.printStackTrace ();} ;72T|e  
} gXjV?"^kUl  
!_"fP:T>  
U-|N
Y
  
//读取保存的下载信息（文件指针位置） uXKERzg  
private void read_nPos() Ry'= ke  
{ _A=$oVe  
try{ ~m$Y$,uH  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )gMG#>up@  
int nCount = input.readInt(); ~P@Q7T*  
nStartPos = new long[nCount]; ypy68_xyW  
nEndPos = new long[nCount]; PS[+~>%  
for(int i=0;i<nStartPos.length;i++) mFi&YpHu3  
{ %T~ig[GstX  
nStartPos = input.readLong(); v&=gF/$  
nEndPos = input.readLong(); o|$AyS{1  
} :$n=$C-wp  
input.close(); kOed ]>H  
} "T|PS6R~  
catch(IOException e){e.printStackTrace ();} A -b [>}_  
catch(Exception e){e.printStackTrace ();} 4y+< dw  
} `5C,N!d8X  
Y 1t\iU  
Wr( y)D<y}  
private void processErrorCode(int nErrorCode) t{.8|d@  
{ D}mjN=Y  
System.err.println("Error Code : " + nErrorCode); "OdXY"G  
} WS`qVL]^&  
'L8' '(eZ^  
R.yC(r  
//停止文件下载 i{`;R  
public void siteStop() GgB,tam{p  
{ ?W)A  
bStop = true; vMm1Z5S/  
for(int i=0;i<nStartPos.length;i++) lGOgN!?i  
fileSplitterFetch.splitterStop(); Vb= Mg  
Wh.?j>vB  
|b)Y#)C;  
} tfGHea)M  
} !s&NT @ S  
//负责部分文件的抓取 yI"6Da6|y  
**FileSplitterFetch.java 1#ft#-g}
 
*/ @9lUSk^9  
package NetFox; v^1pN>#%g  
t$De/Uq  
0DJ+I  
import java.io.*; +Nt2 +Y:O  
import java.net.*; LRNh@g4ei  
9;B0Mq py  
<x<"n t  
public class FileSplitterFetch extends Thread { ;u>DNG|.  
`nZ)>  
egq67S  
String sURL; //File URL E/%9jDTQ  
long nStartPos; //File Snippet Start Position H
xIIO[h  
long nEndPos; //File Snippet End Position Y9&,t\ q  
int nThreadID; //Thread's ID rl#p".4q  
boolean bDownOver = false; //Downing is over B
Btzs^C|  
boolean bStop = false; //Stop identical 3G(miP6
 
FileAccessI fileAccessI = null; //File Access interface %y@Hh=  
p{j.KI s7  
<psZQdH  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~4 `5tb  
{ U15H@h  
this.sURL = sURL; uLWh|
  
this.nStartPos = nStart; E(Z8  
this.nEndPos = nEnd; mD^jd+  
nThreadID = id; D?NbW @]  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #6CC3TJ'k  
} /N&CaH\;^$  
a+%6B_|\  
:(M(>4t  
public void run() 
"CI=`=  
{ !0vG|C;'  
while(nStartPos < nEndPos && !bStop) u
A#P'?  
{ z{o' G3  
'LO^<  
:gep:4&u  
try{ 2fWTY0  
URL url = new URL(sURL); `wDl<[V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,uSQNre\j  
httpConnection.setRequestProperty("User-Agent","NetFox"); -@0GcUE:r  
String sProperty = "bytes="+nStartPos+"-"; x3o]U)^  
httpConnection.setRequestProperty("RANGE",sProperty); 9f<MQ6_UU  
Utility.log(sProperty); }<9cL'  
TzNn^ir=HX  
$3s@}vLd  
InputStream input = httpConnection.getInputStream(); '*"vkgN  
//logResponseHead(httpConnection); NnT1X;0W  
=*r])Vg^  
CnG+Mc^  
byte[] b = new byte[1024]; 3_MS.iM  
int nRead; i?
 K|TC`  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) =5(>q5Z*  
{ $w);5o  
nStartPos += fileAccessI.write(b,0,nRead); {M^3m5.^  
//if(nThreadID == 1) RT.D"WvT  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -UOj>{-  
} d~JKH&x<  
i;_tI#:A  
MMx9(`t*.  
Utility.log("Thread " + nThreadID + " is over!"); PqiB\~o@Z  
bDownOver = true; T
^Ze3L]  
//nPos = fileAccessI.write (b,0,nRead); `s8{C b=}1  
} nv~%#|v_W  
catch(Exception e){e.printStackTrace ();} 8[E!E)
4M  
} 3%%o?8ES  
} fR*q?,  
&i$ldR  
Stu4t==U  
//打印回应的头信息 /Z@tv.f  
public void logResponseHead(HttpURLConnection con) UHTvCc  
{ fngOeLVG  
for(int i=1;;i++) 5a hVeY  
{ ;;:-l99  
String header=con.getHeaderFieldKey(i); l@\#Ywz  
if(header!=null)
hKT  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); rjp-Fw~1w  
Utility.log(header+" : "+con.getHeaderField(header)); !U'QqnT  
else 98uV6b~g  
break; 2gCX}4^3b  
} er!DYv  
} :[hgxJu+  
|~X ;1j!  
L;'"A#Pa  
public void splitterStop() !3 f?:M  
{ =[@zF9  
bStop = true; oaoU _V  
} / ;,Md,p  
_YLfL  
lna}@]oR  
} =A!@6Nw  
.`4{9?bR  
'~&9D:(  
/* L.jh   
**FileAccess.java XbD4:i%  
*//文件访问(定位，写) ^`)) C;  
package NetFox; Ipq"E  
import java.io.*; uFPF!Ern  
7 D^gMN%p  
s0k`p<q  
public class FileAccessI implements Serializable{ jO1r)hw N>  
(tZrw5@  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 JSTuXW  
RandomAccessFile oSavedFile; O"c;|zCc>  
long nPos; y6[IfcN  

|>tKq;/  
YYu6W@m]  
public FileAccessI() throws IOException ZRg;/sX]  
{ SVB\  
this("",0); ~,5gUl?Il  
} 5[YDZ7g"~  
=W BTm  
:]^P1sH[  
public FileAccessI(String sName,long nPos) throws IOException WqXbI4;pJ  
{ sU@nc!&Y@  
oSavedFile = new RandomAccessFile(sName,"rw"); Ux}(?Z  
this.nPos = nPos; Bhp-jq'!B  
oSavedFile.seek(nPos); _PlKhv}  
} )Ccq4i  
'{V0M<O  
?Vf o+a,  
public synchronized int write(byte[] b,int nStart,int nLen) N=QfP  
{ Y!gCMLL  
int n = -1; b7wvaRe.  
try{ tjluk  
oSavedFile.write(b,nStart,nLen); A#95&kJpy  
n = nLen; i*NH'o/  
} I^8"{J.Q)[  
catch(IOException e) zN:K%AiGxe  
{ f^"N!f a  
e.printStackTrace (); Ko&>C_N  
} =y
yp?WmC8  
Bb}fj28  
oWC@w  
return n; D(H>R
&b!  
} &qr;IL7'  
ML8<4o  

~?FpU  
} Ju :CMkv  
s!}ne"&0  
K
NLfp1!  
/* nEkR1^30  
**SiteInfoBean.java G6FEp`  
*/ Dqe^E%mc  
package NetFox; :"IE  
\8 h;K>=h  
eK!V );  
public class SiteInfoBean { nw<&3k(g}  
iCcB@GlA  
}XSfst5-H  
private String sSiteURL; //Site's URL HAJ7m!P  
private String sFilePath; //Saved File's Path o)2W`i&  
private String sFileName; //Saved File's Name  )8UWhl=  
private int nSplitter; //Count of Splited Downloading File AbYqf%~7`l  
.On|uC)!  
5_z33,q2  
public SiteInfoBean()  OPx`u  
{//nSplitter的缺省值为5 LM-J !44  
//default value of nSplitter is 5 hijgF@  
this("","","",5); GrAujc5|  
} pn.T~"%  
n_(/JE>  
PX n;C/  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) AG?dGj^  
{ y1bbILWej  
sSiteURL= sURL; $a"n1ou  
sFilePath = sPath; s+EAB{w$  
sFileName = sName; N0=ac5  
this.nSplitter = nSpiltter; ?hWwj6i&  
9=V:&.L  
HOE_S!N  
} a8i]]1Blz  
W034N[9  
|<.lW  
public String getSSiteURL() +{W>i;U  
{ 3rc
KzS7  
return sSiteURL; X90J!  
}
3+G@g#MY  
f/Hm{<BY  
]b%Hy  
public void setSSiteURL(String value) ?$6Y2  
{ N.]qU d  
sSiteURL = value; 6u`)QUmItg  
} 72Iy^Y[MX  
"Za>ZRR  
k=B]&F  
public String getSFilePath() bV$)!]V  
{ G1"zElug  
return sFilePath; 0DmMG  
} (h5'9r  
G_k~X"  
W81E!RyP`  
public void setSFilePath(String value)
pSr{>;bN  
{ x-AZ%)N9  
sFilePath = value; /~Z?27F6@  
} LK, bO|  
Pp`*]Ib  
bVL9vNK  
public String getSFileName() 3plzHz,x
 
{ 'C ~y5j  
return sFileName; L}}y'^(  
} K!'AkTW+-  
{ Q`QX`#  
f3Hed  
public void setSFileName(String value) Ju3*lk/j-  
{ 1QU:?_\6@t  
sFileName = value; <X7FMNr[  
} 5K<5kHpvJ{  
2;^y4ssg  
Nv/v$Z{k  
public int getNSplitter() y7$iOR  
{ 6
C-/`>m  
return nSplitter; m"fNK$_
d  
} E !a|Xp  
\yd s5g!:  
yfx7{naKC`  
public void setNSplitter(int nCount) e|p$d:#!  
{ USVqB\#  
nSplitter = nCount; KTn}w:+B\  
} mN>h5G>a  
} ~d%Pnw|  
FFH_d <q  
kIGbG;"_  
/* n
iqN{  
**Utility.java `xywho%/Y  
*/ gOr%!QaF  
package NetFox; `S2[5i  
-|Y(V5]  
B:e @0049  
public class Utility { #ceaZn|@m  
xZQg'IT  
9$Xu,y  
public Utility() 2Ri{bWi  
{ /}PF\j9#4  
@*qz(h]\  
C":o/;,1  
} '^Ql]% _  
` bdZ/*E  
//线程睡眠 .hba*dV  
public static void sleep(int nSecond) z%e8K(  
{ K,w"_T  
try{ ;w%*M}`5  
Thread.sleep(nSecond); wQiX<)O  
} #SX8=f`K5  
catch(Exception e) .h& .K  
{ 1XnZy5fEo  
e.printStackTrace (); e89Xb;;w  
} ]]&M@FM2z  
} qWx][D"  
(vB<%l.&  
//日志 @E-\ J7 yh  
public static void log(String sMsg) m^#rB`0;L  
{ nIoPC[%_  
System.err.println(sMsg); `8I&7c  
} g=]u^&  
 k0  
X*,%&6O*  
public static void log(int sMsg) sL@

U  
{ sPpsq  
System.err.println(sMsg); Wa1, p  
} dpFVN[\oK  
} ,uPJ_oZs  
_^
'I  
<7n4_RlF!  
/* qpsvi.S  
**TestMethod.java L9@&2?k  
*/ Qed.4R:o  
package NetFox; \MmI`$  
hTEx]# (  
UH"#2< |b  
public class TestMethod { -CR?<A4mud  
/MF!GM  
hTM[8 ~<^  
public TestMethod() ~O]]N;>72"  
{ ///xx/weblogic60b2_win.exe !Mu|m
z=  
try{ \|Ul]1pO8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); PmR~c,  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 0k'e:AjP  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Ezi-VGjr]  
fileFetch.start(); ^m/oDB-  
} =e}H'5?!  
catch(Exception e){e.printStackTrace ();} "n: %E  
ZWm8*}3]7_  
!TP@- X;  
} yY&3p1AxW]  
R-RDT9&<  
:mS# h@l  
public static void main(String[] args) 3"kdjOB  
{ 9Li%KOY  
new TestMethod(); `iJhG^w9M  
} fsEzpUY:{W  
} h@@nR(<i  
点击下载更多相关资料