http断点续传简单实现（java)

/* vo<#sa^,j  
**SiteFileFetch.java 3a[(GW _  
*/ |g^W @.P  
package NetFox; ovoI~k'  
import java.io.*; eii7pbc  
import java.net.*; RV*Zi\-X  
PC7.+;1  
MAo,PiYb  
public class SiteFileFetch extends Thread { 5GxM?%\  
`.-k%2?/  
m@2xC,@  
SiteInfoBean siteInfoBean = null; //文件信息Bean Bw7:ry  
long[] nStartPos; //开始位置 Id
7  
long[] nEndPos; //结束位置 cMk%]qfVo8  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 C`<} nx1  
long nFileLength; //文件长度 {:8[Mdf  
boolean bFirst = true; //是否第一次取文件 TUn@b1
1  
boolean bStop = false; //停止标志 ")gCA:1-  
File tmpFile; //文件下载的临时信息 $^aXVy5p  
DataOutputStream output; //输出到文件的输出流 3Qr!?=nf  
&rWJg6/  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &Gwh<%=U  
public SiteFileFetch(SiteInfoBean bean) throws IOException l"!;Vkg.5  
{ <RsKV$Je I  
siteInfoBean = bean; Kd1\D!#!6  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); X}FF4jE]D(  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ,#;ahwU~s  
if(tmpFile.exists ()) IL"#TKKv  
{ jCv+m7Z  
bFirst = false; VQx-gm8}!  
read_nPos(); _1%^ibn  
} R~(.uV`#j  
else Ym2
m1  
{ A2bV[+Q
 
nStartPos = new long[bean.getNSplitter()]; hs uJ;4}$q  
nEndPos = new long[bean.getNSplitter()]; &.4a  
} qr;" K?NX  
3AL=*qq  
G7JZP T  
LtIZgOd<  
} /VZU3p<~  
% 7:  
^Wz{su2  
public void run() %6:2cR  
{ UzwIV{  
//获得文件长度 )U`kU`+'  
//分割文件 Tj+WO6#V  
//实例FileSplitterFetch 5X-{|r3q  
//启动FileSplitterFetch线程 !]T|=yw  
//等待子线程返回 '(>N gd[  
try{ ?`}U|]c  
if(bFirst) t\0JNi$2  
{ m_f^#:  
nFileLength = getFileSize(); J>v>6OC6i  
if(nFileLength == -1) 4"=pcHNV  
{ (o=iX,@'2  
System.err.println("File Length is not known!"); Q{kuB+s  
} Y[,C1,  
else if(nFileLength == -2) Vi-@z;k  
{ [0@i,7{ZqE  
System.err.println("File is not access!"); KJSy7F  
} qm_E/B  
else 9V!K._Cb  
{ ,%<77LE  
for(int i=0;i<nStartPos.length;i++) *E6 p=  
{ Bqj*{m  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); G;+0V0K  
} r?7^@  
for(int i=0;i<nEndPos.length-1;i++) O-YE6u  
{ @#">~P|Hp  
nEndPos = nStartPos[i+1]; H#akE\,  
} uBJF}"4ej  
nEndPos[nEndPos.length-1] = nFileLength; $5O&[/L  
} >8- `  
} _JoA=<O!  
Yuck]?#0  
K~G^jAk+  
//启动子线程 A":x<9   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; s5@^g8(+C  
for(int i=0;i<nStartPos.length;i++) W;W\L? r  
{ ;kA2"c]m  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \t3
i9#Q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), wEyh;ID3#  
nStartPos,nEndPos,i); [c~zO+x  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ado>)c"*y1  
fileSplitterFetch.start(); J{I?t~u  
} wDzS<mm  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), vzPrG%Uu7g  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); p};<l@  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ='azVw%_  
nEndPos = " + nFileLength); |ESe=G  
// fileSplitterFetch[nPos.length-1].start(); 
e9nuQ\=  
$:/1U$  
S7]cF5N  
//等待子线程结束 *2Kte'+q  
//int count = 0; Ft7l/  
//是否结束while循环 DoA f,9|_  
boolean breakWhile = false; aQuENsB  
-#h \8Xl  
eS M!_2  
while(!bStop) u5,<.#EVY  
{ JM0)x}]+  
write_nPos(); _Yv9u'q"  
Utility.sleep(500); f.WtD`Oas  
breakWhile = true; p+Xz9A"  
-i4gzak  
R8_qZ;t:z  
for(int i=0;i<nStartPos.length;i++) !+U.)u9 '  
{ LE"xZxe  
if(!fileSplitterFetch.bDownOver) -lHJ\=  
{ >"b"
K{t  
breakWhile = false; ZO}*^  
break; 5NK:94&JE  
} z Ey&%Ok  
} 9i@*\Ada  
if(breakWhile) w*x}4wW  
break; F);C?SW"  
?*HlAVDcFT  
Oi RqqD  
//count++; i "xq SLf=  
//if(count>4) O`4X[r1LD  
// siteStop(); Q{l;8MCL  
}
<=lP6B  
!G37K8&&*  
7e4\BzCC  
System.err.println("文件下载结束！"); OpfFF;"A'  
} n!2|;|$}Z  
catch(Exception e){e.printStackTrace ();} i?]!8J
i  
} t+ @F"[j  
m`|+_{4[n  
j56Y,Tm  
//获得文件长度 Wl{Vz  
public long getFileSize() uPpP")  
{
#HML=qK~  
int nFileLength = -1; ;Ti?(n#M>  
try{ QLn5:&  
URL url = new URL(siteInfoBean.getSSiteURL()); K4~dEZ   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); TD@'0MaQ#  
httpConnection.setRequestProperty("User-Agent","NetFox"); dbR4%;<  
6BMn7m?  
}[|"db  
int responseCode=httpConnection.getResponseCode(); +KZc"0?
 
if(responseCode>=400) &b%6pVj  
{ ,b/0_Q  
processErrorCode(responseCode); >2ct1
_  
return -2; //-2 represent access is error 5:6mptn>  
} QP'* )gjO7  
(NP=5lLH  
W'[!4RQL  
String sHeader; d-4u*>  
a&&EjI  
*i|hcDk  
for(int i=1;;i++) p^2pv{by  
{ qsLsyi|zG  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); HHdc[pJ0D  
//Utility.log(in.readLine()); kG E|17I  
sHeader=httpConnection.getHeaderFieldKey(i); h<uQ~CQg  
if(sHeader!=null) R!`#pklB  
{ UV=TU=A\o  
if(sHeader.equals("Content-Length")) ls=<c<  
{ 1i{B47|  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &]5<^?3  
break; Zhw _L  
} d(&vIjy  
} 7+0hIKrFC  
else Z]aSo07  
break; YWTo]DJV  
} sM4N`$Is23  
} m<j ^cU#J  
catch(IOException e){e.printStackTrace ();} 3B,nHU  
catch(Exception e){e.printStackTrace ();} L\"$R":3{d  
Z|)~2[Roa  
b{sFN!  
Utility.log(nFileLength); wM><DrQ  
\]^|IViIQ  
ym:JtI69   
return nFileLength; y jb.6  
} d;f,vN(  
0FXM4YcrJO  
bw@tA7Y  
//保存下载信息（文件指针位置） 8F%TZM  
private void write_nPos() SN11J+  
{ lcih [M6z  
try{  /8.;  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ;$nK ^  
output.writeInt(nStartPos.length); m^`X|xK-  
for(int i=0;i<nStartPos.length;i++) b*,R9  
{ Ros5]5=dP  
// output.writeLong(nPos); :yv!
 x  
output.writeLong(fileSplitterFetch.nStartPos); JjM^\LwKkL  
output.writeLong(fileSplitterFetch.nEndPos); ! $n^Ze2 !  
} W2REwUps  
output.close(); p_qH7W  
} GSl\n"S]=  
catch(IOException e){e.printStackTrace ();} U5Rzfm4  
catch(Exception e){e.printStackTrace ();} }D0j%~&"e  
} `W"-jz5#=  
$ \jly  
&98qA
O]Z  
//读取保存的下载信息（文件指针位置） F M`pPx  
private void read_nPos() n6oVx5/  
{ |ek*wo  
try{ e&E*$G@.7  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); qWo|LpxWt  
int nCount = input.readInt(); DD;PmIW  
nStartPos = new long[nCount];  Vb/J`  
nEndPos = new long[nCount]; m|p}Jf!  
for(int i=0;i<nStartPos.length;i++) }V`Fz',lZ  
{ Q&wBX%@^L  
nStartPos = input.readLong(); S!rUdxO  
nEndPos = input.readLong(); 7/Ew(X8Fs  
} Z$2mVRS`c  
input.close(); )M1.>?b  
} csYICLj  
catch(IOException e){e.printStackTrace ();} kD
2MqR>  
catch(Exception e){e.printStackTrace ();} Yzd-1Jvk  
} >5 Ce/P'R  
Oi7|R7NE  
<{e0i  
private void processErrorCode(int nErrorCode) %R(j|a9z  
{ | YvO$4=s  
System.err.println("Error Code : " + nErrorCode); Yh"R#  
} S7-?&[oeJ  

s*rtm  
Rb#?c+&
#  
//停止文件下载 5FzG_ w  
public void siteStop() V$@@!q  
{ w W-GBY3  
bStop = true; 6Bs_" P[  
for(int i=0;i<nStartPos.length;i++) |Y:T3hra61  
fileSplitterFetch.splitterStop(); 6?2/b`k  
G>cTqD6gT  
wtMS<$  
} !! #\P7P  
} 8iq~ha$]|  
//负责部分文件的抓取 jt?R a1Z  
**FileSplitterFetch.java z^~fVl  
*/ =n%?o
Lg^  
package NetFox; ^]OD+
v  
~d28"p.7  
AlGD .K  
import java.io.*; +BmA4/P$  
import java.net.*; ]5c|  
gn7pIoN
 
IiSO{  
public class FileSplitterFetch extends Thread { 3
vDV   
tWD*uAb  
ZO:{9vt=/  
String sURL; //File URL T7&itgEYG/  
long nStartPos; //File Snippet Start Position <4^a(Zh  
long nEndPos; //File Snippet End Position @ -g^R4e<  
int nThreadID; //Thread's ID :y0'[LV  
boolean bDownOver = false; //Downing is over &:w{[H$-  
boolean bStop = false; //Stop identical :'#BU:  
FileAccessI fileAccessI = null; //File Access interface hnL(~  
%kKtPrT  
jUdW o}/  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &9IMZAo  
{ BYP,}yzA  
this.sURL = sURL; !dGy"-i$h  
this.nStartPos = nStart; 1 BVivEG
 
this.nEndPos = nEnd; ;z!~-ByzL  
nThreadID = id; 2x'JR yef  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 .b5B7x}  
} d
7P| x  
L<J%IlcfO  
wN"irXG  
public void run() K@%.T#  
{ 6<FJ`l]U9  
while(nStartPos < nEndPos && !bStop) E9QNx62  
{ 7vgz=- MZ#  
dEns|r  
si0jXue~j\  
try{  XW`&1qx  
URL url = new URL(sURL); ^i#F+Q`1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;\(wJ{u?Y  
httpConnection.setRequestProperty("User-Agent","NetFox"); \Ui8Sgeei  
String sProperty = "bytes="+nStartPos+"-"; v:<u0B-)$  
httpConnection.setRequestProperty("RANGE",sProperty); j =[Td  
Utility.log(sProperty); g7#_a6  
,!PNfJA2  
dLG5yx\js  
InputStream input = httpConnection.getInputStream(); %]RzC`NZ  
//logResponseHead(httpConnection); F71.%p7C8"  
Bglh}_X  
RwN*/Li  
byte[] b = new byte[1024]; bQEQHqY5  
int nRead; !)KX?i[Q  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) dorZ O2Uc  
{ <eb>/ D  
nStartPos += fileAccessI.write(b,0,nRead); yAXw?z!`O  
//if(nThreadID == 1) <c^m
|v  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f`P%aX'cBQ  
} DYbkw4Z,  
&\`=}hB  
0|HD(d`a  
Utility.log("Thread " + nThreadID + " is over!"); qzsS"=5  
bDownOver = true; pOpie5)7X  
//nPos = fileAccessI.write (b,0,nRead); v6TH-  
} $v$
~.  
catch(Exception e){e.printStackTrace ();} E.4`aJ@>d  
} tb^3-ZUb  
} XEY((
VL0  
zEpcJHI%  
9kQ~)4#  
//打印回应的头信息 ,`)!K}2  
public void logResponseHead(HttpURLConnection con) Sh}AGNE'  
{ GYyP+7K4l[  
for(int i=1;;i++) r4D6g>)h1q  
{ l^WFMeMD3a  
String header=con.getHeaderFieldKey(i); ,B h[jb`y  
if(header!=null) )#M*@e$k  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ga"$_DyM  
Utility.log(header+" : "+con.getHeaderField(header)); 2y v'DS  
else 2Pasmh  
break; 3QZw  
} $yI!YX&  
} ?:~Y%4;  
}vPDCUZ  
I( G8cK  
public void splitterStop() ,=R->~ J  
{ %)?$82=2  
bStop = true; VLkK6W.u  
} ;:a7rN"(  
e:6R+8s2  
C$-IDBXK  
} 5<Xq7|Jt  
[D^KM|I%+  
a<rk'4,8a  
/* lX;2~iW{/  
**FileAccess.java )1Z*kY?f!  
*//文件访问(定位，写) w-
"o?;)a  
package NetFox; q;InFV3rv  
import java.io.*; wBA[L}   
d {T3  
k#w[GL|T  
public class FileAccessI implements Serializable{ 3;>|*(cO  
U;LbP-{B  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 m("! M~1  
RandomAccessFile oSavedFile; Jx[
IHE  
long nPos; =k2In_  
bWW$_Spr  
"
P~07  
public FileAccessI() throws IOException 6&`.C/"2  
{ #7/_Usso  
this("",0); &zynfj#
o  
} U(3{6^>Gc  
GBGGV#_q'}  
"'~'xaU!=a  
public FileAccessI(String sName,long nPos) throws IOException kViX FPW  
{ CZS{^6Ye  
oSavedFile = new RandomAccessFile(sName,"rw"); Q!(C$&f  
this.nPos = nPos; ,9`sC8w|  
oSavedFile.seek(nPos); > 't=r  
} fj[B,ua  
<9@I50;  
4Sfv  
public synchronized int write(byte[] b,int nStart,int nLen) +3(1QgYM%  
{ _iO,GT=J-  
int n = -1; I;S[Ft8
d  
try{ $RuJm\f  
oSavedFile.write(b,nStart,nLen); :CNHN2 J  
n = nLen; a<B[~J4i  
} X@*$3z#Z  
catch(IOException e) 5P,{h  
{ Z}5;K"T/  
e.printStackTrace (); .:B] a7b  
} ?J<Y]  
\`Db|D?oy  
?a+tL'D[  
return n; 35%'HFt_  
} NX4!G>v  
I!%T!B540  
Em N0K'x  
} Bmm#5X@*  
K{%}kUj>  
]s?BwLU6  
/* H-K,Q%;C@  
**SiteInfoBean.java ;H9d.D8  
*/ ]j(2FM)#  
package NetFox; BSY2\AL p  
Yc/Nz(m  
k-@CcrepF  
public class SiteInfoBean { TPZZln'3   
/d ?)  
,a9<\bd)  
private String sSiteURL; //Site's URL ;;pxI5  
private String sFilePath; //Saved File's Path c^S^"M|  
private String sFileName; //Saved File's Name 9[N+x2q  
private int nSplitter; //Count of Splited Downloading File lX/6u E_%  
dq%7A=-  
ZRf-V9  
public SiteInfoBean() -o#HO_9  
{//nSplitter的缺省值为5 $?YRy_SI  
//default value of nSplitter is 5 RLOB  
this("","","",5); ^a4y+!  
} "45O!AjP  
&~ QQZ]q6  
sPYG?P(l  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) "Sz pFw  
{ ()6)|A<^U  
sSiteURL= sURL; D^W6Cq5\  
sFilePath = sPath; /-TJtR4>  
sFileName = sName;
,ilVt  
this.nSplitter = nSpiltter; `VCU`Y
  
DBYD>UA  
x_CB'Rr6  
} !2s< v
 
Nc:, [8{l  
/-Y*V*E  
public String getSSiteURL() W2G`
K+p  
{ jbcJ\2  
return sSiteURL; -h%;L5oJ2,  
} *|h-iA+9  
<*E{zr&  
cVv+,l4V0  
public void setSSiteURL(String value) cobq+Iyu  
{ +/y 3]}  
sSiteURL = value; M)C.bo{p  
} Y O;N9wu3f  
xWWfts1t  
/PH+K24v~  
public String getSFilePath() u0`~ |K  
{ B- =*"H?q  
return sFilePath; -(V]knIF  
} P
Lf
  
p1 > D  
p(in.Xz  
public void setSFilePath(String value) >H?l[*9  
{ 9=7),`$  
sFilePath = value; j38>,9u,  
} XP~bmh,T,  
&@u;xc| v  
-fFM-gt^t  
public String getSFileName() H RJz  
{ lp3 A B  
return sFileName; 7K>FCT  
} -bJht  
Vb*q^ v  
c-.t8X,5(~  
public void setSFileName(String value) Z(Fsk4,  
{ pMnkh}Q#  
sFileName = value; h$.y)v  
} KSU?Tg&JR  
e0Cr>I5/e  
9AK<<Mge.  
public int getNSplitter() iD+Q\l;%  
{ b3N>RPsHS  
return nSplitter; :M)B#@ c=  
} 6C@,&2<yK  
g N76  
*ci,;-*C  
public void setNSplitter(int nCount)
w|!>>W6J  
{ )_N|r$i\  
nSplitter = nCount; (yIl]ZN*  
} Se7NF@>9_  
} W}
p>jP}  
j_Pt8{[  
U?97yc\$  
/* ImO
\X`{  
**Utility.java v1%rlP  
*/ )X2=x^u*U  
package NetFox; u~FXO[b  
jH#Tt;  
&^$dHr6v  
public class Utility { t<s:ut)Q!  
zBD ?O!  
T;K,.a8bU  
public Utility() rM<|<6(L  
{ m-9{@kgAM?  
EEFM1asJf  
E/z^~;KA  
} ~H!s{$.5  
M&o@~z0  
//线程睡眠 {E`[`Kf  
public static void sleep(int nSecond)  Ht|No  
{ gjB36R  
try{ }PdS?[R  
Thread.sleep(nSecond); 7wS)'zR;  
} +M-x*;.  
catch(Exception e) ZlD\)6 dZ  
{ C%#=@HC  
e.printStackTrace (); 7.)e4  
} COPH)Bdq.  
} Y-\/Y*;cd  
aC:Sy^Tf  
//日志 5q?2?j/h  
public static void log(String sMsg) D#|+PG7  
{ $/^DY&  
System.err.println(sMsg); ~?i;~S  
} Si#I^aF`%  
KPO?eeT.WZ  
ZYD
Ll8  
public static void log(int sMsg) a_Y*pOu  
{ dU%Q=r
8R  
System.err.println(sMsg); <?UbzT7X  
} j}R!'m(P'  
} eaLSq  
&5>R>rnB  
*ub]M3O  
/* 88(h`RGMh  
**TestMethod.java h
?E[28QB  
*/ Gq%q x4  
package NetFox; 3\_ae2GW  
T(t@[U2^  
kSx^Uu*  
public class TestMethod { L1=+x^WQ  
%xZYIYKf  
BUT{}2+K  
public TestMethod() 2@K D '^(  
{ ///xx/weblogic60b2_win.exe _h|rH  
try{ *ue- x!"c  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); b|mWEB.p  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); A;~lG3j4  
SiteFileFetch fileFetch = new SiteFileFetch(bean); lnuf_;0  
fileFetch.start(); GPBp.$q+B  
} QHOA__?  
catch(Exception e){e.printStackTrace ();} 9qc<m'MZ  
G"w ?{W@  
_GEt:=DAP#  
} K=,nX7Z5  
)p*I(y  
VN!`@
Ci/  
public static void main(String[] args) S+(TRIjk  
{ q =sEtH=  
new TestMethod(); ":s1}A  
} al>^}:  
} RsV<4$  
点击下载更多相关资料