http断点续传简单实现（java)

/* nx`W!|g$`  
**SiteFileFetch.java JKp@fQT *  
*/ ?JRfhJ:j  
package NetFox; 4u|6^wu.I  
import java.io.*; biV|W@JM  
import java.net.*; #Sg/  
uGl
z|C  
M>RLS/r>d  
public class SiteFileFetch extends Thread { NJ}xqg  
T3)m{gv0`  
?|2m0~%V=  
SiteInfoBean siteInfoBean = null; //文件信息Bean m^0*k|9+G  
long[] nStartPos; //开始位置 ?~}8^~3  
long[] nEndPos; //结束位置 RvVF^~u  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 @*T8>  
long nFileLength; //文件长度 XxB%  
boolean bFirst = true; //是否第一次取文件 (|6!pQ7  
boolean bStop = false; //停止标志 7S&O{Q7)  
File tmpFile; //文件下载的临时信息 [)[?FG9   
DataOutputStream output; //输出到文件的输出流 +C`vO5\0  
{iLr$89  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） RKs
_k`N0  
public SiteFileFetch(SiteInfoBean bean) throws IOException .$G^c  
{ j\.pS^+  
siteInfoBean = bean; 0j#$Swa  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); xr)m8H  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 'HvW&~i(  
if(tmpFile.exists ()) ER]C;DYX  
{ ocp3JR_0  
bFirst = false; |@>Zc5MY$  
read_nPos(); MhFj>t   
} qP%[nY  
else T5-'|+  
{ |>I4(''}  
nStartPos = new long[bean.getNSplitter()]; kP~ ;dJD  
nEndPos = new long[bean.getNSplitter()]; 9fSX=PVRmQ  
} uTrGb:^  
rPW9lG  
cz>`$Zz  
"Jyb?5  
} y3V47J2o  
t&bE/i_T  
.|kp`-F51  
public void run() U@:iN..  
{ 5i3nz=~o  
//获得文件长度 T:j!a{_|  
//分割文件 pHDPj,lu  
//实例FileSplitterFetch uUpOa+t  
//启动FileSplitterFetch线程 ~65lDFY/  
//等待子线程返回 `p^xdj}  
try{ `jFvG\aC  
if(bFirst) a<D]Gz^h  
{ [;INVUwG^  
nFileLength = getFileSize(); MES|iB
 
if(nFileLength == -1) I1Gk^wO  
{ 0jefV*3qpB  
System.err.println("File Length is not known!"); '-X913eG!  
} j7&0ckN&G  
else if(nFileLength == -2) MdNV3:[\  
{ oxqD/fY  
System.err.println("File is not access!"); dG]s_lb9H  
} 5HbPS%^.  
else Vuo 8[h>  
{ {[B`q  
for(int i=0;i<nStartPos.length;i++) iuq%Q\0@w  
{ b{JxTT}03  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Sh5SOYLz  
} laFF/g;sRC  
for(int i=0;i<nEndPos.length-1;i++)
h|=&a0  
{ G Q+g.{c  
nEndPos = nStartPos[i+1]; w.0]>/C  
} h5#V,$  
nEndPos[nEndPos.length-1] = nFileLength; le`_  
} gI~jf- w  
} $3n@2 N`  
lhV'Q]s@6  
.7GAGMNS  
//启动子线程 ?r6uEZ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];
fL1EQ)  
for(int i=0;i<nStartPos.length;i++) F_Mi/pB^`9  
{ G@n%P~  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =l9H]`T/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), =}AwA5G  
nStartPos,nEndPos,i); AJH-V 6  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ax+q/nvnb  
fileSplitterFetch.start(); SA$1rqU=  
} .!J,9PE  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?l<u%o  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); lN^} qg><  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", nM)H2'%kL&  
nEndPos = " + nFileLength); [P_1
a`b  
// fileSplitterFetch[nPos.length-1].start(); @oL<Ioh  
vl}uHdeP9  
y/@.T\p  
//等待子线程结束 W|kKH5E&  
//int count = 0; I806I@ix  
//是否结束while循环 a<X<hxW:  
boolean breakWhile = false; ^^Tu/YC9x  
wMB<^zZmv  
N^.!l_  
while(!bStop) GzUgzj|BN~  
{ 3l@={Ts  
write_nPos(); ~FV Z0%+,  
Utility.sleep(500); i;>Hy|  
breakWhile = true; vb.`rj6  
_,4f z(  
Ls^$E  
for(int i=0;i<nStartPos.length;i++) =2eG j'}  
{ e$^O_e  
if(!fileSplitterFetch.bDownOver) Ci ? +Sl  
{ ;-d :!*  
breakWhile = false; M-df Gk  
break; 6!n%SUt  
} b1;80P/:D  
} )xQA+$H#4  
if(breakWhile) [ Q6v#I  
break; 1vQj` F  
[Hww3+~+  
7Jm9,4]  
//count++; 8W"~>7/>D  
//if(count>4) rX#}2  
// siteStop(); 5sq#bvfJ o  
} LPk85E  
@`ttyI^1f  
~WJEH#  
System.err.println("文件下载结束！"); B/Lx,

 
} q<b;xx  
catch(Exception e){e.printStackTrace ();} (k..ll p~  
} J,E'F!{  
+'x`rk
 
xla9:*pPn  
//获得文件长度 M+ gYKPP  
public long getFileSize() 'qhA4W9  
{ <c6C+OWT,  
int nFileLength = -1; k]"Rg2
>%  
try{ ,g$N  
URL url = new URL(siteInfoBean.getSSiteURL()); Ee##:I[z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); X] /r'Tz  
httpConnection.setRequestProperty("User-Agent","NetFox"); s Hu~;)  
'@iS5Fni  
~J6c1jG  
int responseCode=httpConnection.getResponseCode(); dt 4_x1  
if(responseCode>=400) Ss&R!w9p  
{ jv]:`$}G\  
processErrorCode(responseCode); '+|{4-V  
return -2; //-2 represent access is error 4 |N&Y  
} @fbB3  
% ;2x.  
Nze#u;  
String sHeader; #]|9aVrr  
ge[+/$(1  
d*T;RBk  
for(int i=1;;i++) CBTa9|57  
{ ?/~7\ '|Z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); xU^Flw,4  
//Utility.log(in.readLine()); uM0z%z5b  
sHeader=httpConnection.getHeaderFieldKey(i); cv0}_<Tyx  
if(sHeader!=null) g/4.^c  
{ @`?"#^jT  
if(sHeader.equals("Content-Length")) lYeot8  
{ X.g")Bt7  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); quU%9m \S`  
break; 0@t/j<5o  
} Eq.?Ga  
} ZSMOq4Y 9  
else ue$\i=jw  
break; .Lp0_R@  
} G;MgrA#\  
} hsljJvs
 
catch(IOException e){e.printStackTrace ();} 5Y)!q?#H  
catch(Exception e){e.printStackTrace ();} fdzD6KZI  
o;\0xuM@  
2HMlh.R(C  
Utility.log(nFileLength); ?PSm) ~Oa  
rBkf@  
Vl?R?K=`~J  
return nFileLength; OlFls 8#>  
} kN;l@>  
oHbEHS61  
'd1E~A  
//保存下载信息（文件指针位置） ,l`q  
private void write_nPos() Sz"J-3b^  
{ TjlKy  
try{ e0*',  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ZV_Z)<  
output.writeInt(nStartPos.length); ^&DHBx"J  
for(int i=0;i<nStartPos.length;i++) %n9}P , ?  
{ *#frbV?;  
// output.writeLong(nPos); S0g5Ym ia  
output.writeLong(fileSplitterFetch.nStartPos); Ps.O.2Z5ZB  
output.writeLong(fileSplitterFetch.nEndPos); wI}5[m  
} E'&UWDh  
output.close(); >&aFSL,f  
} rG
Rxofi.  
catch(IOException e){e.printStackTrace ();} IX^k<Jqr  
catch(Exception e){e.printStackTrace ();} Jnm{i|6N  
} f 7et  
?U2ed)zzw  
}jfU qqFd  
//读取保存的下载信息（文件指针位置） +vLuzM-  
private void read_nPos() 'sY>(D*CQ  
{ co<){5zOT  
try{ 7vcYI#(2 Y  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); klKAwCQ,  
int nCount = input.readInt(); @ MNL  
nStartPos = new long[nCount]; < 7zyRm@S  
nEndPos = new long[nCount]; g^^%4Y  
for(int i=0;i<nStartPos.length;i++) +:~&"U^z&  
{ @iy ^a  
nStartPos = input.readLong(); )"jG)c^1*  
nEndPos = input.readLong(); i,FG?\x@  
} _ts0@Z_:  
input.close(); netKt_  
} _$
wWKJy9  
catch(IOException e){e.printStackTrace ();} i?'HVx  
catch(Exception e){e.printStackTrace ();} }!& w<wR  
} M,t8<y4W/  
@"kA&=0;|J  
i,S%:0c7)  
private void processErrorCode(int nErrorCode) v(=fV/  
{ nV McHN   
System.err.println("Error Code : " + nErrorCode); HQaKG4Z  
} [lQp4xgxi  
,ye>D='  
%g0"Kj5  
//停止文件下载 }`IN5NdYp  
public void siteStop() c$?qN&X_K  
{ eP'e_E  
bStop = true; nPfVZG
t  
for(int i=0;i<nStartPos.length;i++) <hdR:k@#  
fileSplitterFetch.splitterStop(); //e.p6"8h  
)wpBxJ;dB}  
/+sn-$/"i  
} 
rc*3k  
} 5gGYG]*l  
//负责部分文件的抓取 W&z.O  
**FileSplitterFetch.java >?b/_O  
*/ c"H4/,F  
package NetFox; GfJm&'U&  
0X0HDQ  
/zuU  
import java.io.*; WaN0$66[:  
import java.net.*; d<V+;"
>2  
"
a5?cX;  
7u!R 'D  
public class FileSplitterFetch extends Thread { (bH"x  
2j4VW0:  
X||oiqbY  
String sURL; //File URL {;Mcor3  
long nStartPos; //File Snippet Start Position .+ai dWd  
long nEndPos; //File Snippet End Position 88pz<$  
int nThreadID; //Thread's ID /Rx%}~x/m  
boolean bDownOver = false; //Downing is over t{!}^{ "5  
boolean bStop = false; //Stop identical emw3cQ  
FileAccessI fileAccessI = null; //File Access interface /.$n>:XR  
@6 gA4h  
!F;W#Gc  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )`-9WCd&  
{ &
]pW##  
this.sURL = sURL; TxN#3m?G  
this.nStartPos = nStart; @XDU!<N  
this.nEndPos = nEnd; 5^GUuFt5m  
nThreadID = id; z6|P]u  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 E} Uy-  
} }/(fe`7:  
?*4&Z.~J  
isDBNXV:  
public void run() 8\. #  
{ 0D|^S<z6  
while(nStartPos < nEndPos && !bStop) o*f7/ZP1o  
{ (IIOKx_  
d|j3E  
'e7<&wm ia  
try{ 8T
h|'  
URL url = new URL(sURL); A37Z;/H~k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
3,oFT   
httpConnection.setRequestProperty("User-Agent","NetFox"); AJ^9[j}  
String sProperty = "bytes="+nStartPos+"-"; pL.r 9T.  
httpConnection.setRequestProperty("RANGE",sProperty); S<88>|&n]  
Utility.log(sProperty); Nypa,_9}  
m,Q<4'  
H:,rNaz7D^  
InputStream input = httpConnection.getInputStream(); jp=^$rS6[  
//logResponseHead(httpConnection); x?va26FV  
2Ev~[Hb.  
lY.FmF}k  
byte[] b = new byte[1024]; mZ7.#R*}  
int nRead; 9i yNR!  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) d@7 ]=P:  
{ WkXa%OZ  
nStartPos += fileAccessI.write(b,0,nRead); 2P!Pbl<  
//if(nThreadID == 1) s7(mNpo  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R\A5f\L9  
} iW-w?!>|m  
2[r#y1ro  
k U*
\Fa*E  
Utility.log("Thread " + nThreadID + " is over!"); d=xU f`^  
bDownOver = true; O6Xu/X]  
//nPos = fileAccessI.write (b,0,nRead); 4}W*
,&_  
} #&1mc_`/  
catch(Exception e){e.printStackTrace ();} 4@/
[aFH  
} h[ba$S,T  
} z1T.\mzfX  
$w)y
Q %  
Rl.3p<sX  
//打印回应的头信息 SEIGs_^'\  
public void logResponseHead(HttpURLConnection con) Q;)[~p  
{ ,K+K`"Oy  
for(int i=1;;i++) (/v(.t  
{ 9{'GrL  
String header=con.getHeaderFieldKey(i); Jq<&`6hn  
if(header!=null) Ad9'q!_en  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); J6n@|L!yO  
Utility.log(header+" : "+con.getHeaderField(header)); (](:0H  
else ,m8l /wG  
break; -%5*c61  
} (pREo/T  
} < :<E~anH  
9Fv1D  
XBF#ILJ  
public void splitterStop() owmV7E
1  
{ |@sUN:G4k  
bStop = true; CS:j->  
} k9.@S  
vCFMO3  
^UEI`_HO0  
} t}c ymX
~  
BCJo/m  
fp.,MIS  
/* rNO'0Ck=
 
**FileAccess.java V~+Oil6sa  
*//文件访问(定位，写) Q\<C9%a  
package NetFox; ,gUSW  
import java.io.*; &UEr4RK;I  
c]
$X+  
|bQKymS  
public class FileAccessI implements Serializable{ 4sP0oe[h  
u+&BR1)C  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节
7!]$XGz[  
RandomAccessFile oSavedFile; 0x4Xs  
long nPos; E2Q;1Re@  
mHM38T9C%
 
b" 1a7  
public FileAccessI() throws IOException FF0N{bY  
{ 3yszfWr  
this("",0); "n^h'// mn  
} /a[i:Oa#  
blpX_N  
r?nvJHP  
public FileAccessI(String sName,long nPos) throws IOException @mSdksB/L  
{ X#EMmB!  
oSavedFile = new RandomAccessFile(sName,"rw"); ONH!ms(kb  
this.nPos = nPos; AME3hA  
oSavedFile.seek(nPos); )^qM%k8  
} cV\(Z6u  
xdFm-_
\-  
-y5^xR  
public synchronized int write(byte[] b,int nStart,int nLen) Ur6UE2  
{ 8`v+
yHjG  
int n = -1; !trt]?*-  
try{ TD'RvTpl  
oSavedFile.write(b,nStart,nLen); *T-+Pm-Cq  
n = nLen; FIL?nk
YEO  
} (0/,R  
catch(IOException e) 5z~rl}`v  
{ Iojyku\W.  
e.printStackTrace (); IDQ@h`"B  
} x{6KsYEY  
,)TtI~6Q  
x_pS(O(C  
return n; I<`K;El'  
} P^&%T?Y6z  
)h]~< fU  
9t:F![rg  
} #` Q3Z}C  
;IZ*o<_  
VgD z:j  
/* ,m;S-Im_Xr  
**SiteInfoBean.java Jr$,w7tQn@  
*/ PIR#M('  
package NetFox; tJ>%Xop  
N:?U
A  
GvSSi'q~B  
public class SiteInfoBean { <o@&I " o  
ajC'C!"^Ty  
Px{Cvc  
private String sSiteURL; //Site's URL e/Wrm^]y  
private String sFilePath; //Saved File's Path Ydm0  
private String sFileName; //Saved File's Name 6i|5`ZO  
private int nSplitter; //Count of Splited Downloading File x)N$.7'9OJ  
)9I>y2WU~  
i8iv{e2  
public SiteInfoBean() _1Iy/T@1  
{//nSplitter的缺省值为5 KJn@2x6LP  
//default value of nSplitter is 5 Ir&rTGFN  
this("","","",5); }(k#,&Fv`  
} @ol=gBU  
*`2.WF@E)  
=lT~  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) HK&Ul=^VN|  
{ ,cZhkXd  
sSiteURL= sURL; l/1u>'  
sFilePath = sPath; GKT2x '(e  
sFileName = sName; ~A@T_*0  
this.nSplitter = nSpiltter; cq lA"Eof  
G&=4@pLY5  
,)/gy)~#  
} (3cJ8o>&  
x93h{Kf  
Zk,` Iq  
public String getSSiteURL() kt`_n+G  
{ .c__<I<G<  
return sSiteURL; EQ 'L"  
} )4:K@  
qTSyy=  
~tK4C|  
public void setSSiteURL(String value) Hdvtgss!  
{ CD]hi,B_J  
sSiteURL = value; o>WB,i^G  
} <Qg).n>;z  
8(-V pU  
4/KGrY!ck  
public String getSFilePath() 4<V%7z_.B  
{ 3y^PKIIrt  
return sFilePath; loRT+u$&  
} H<_BnT#  
dbn9t7'{  
L\0;)eJ#M  
public void setSFilePath(String value) LLyw9y1  
{ %+ln_lgD:  
sFilePath = value; ot\  FZ  
} ;f;A"  
F1_s%&  
w O H{L  
public String getSFileName() (V&5EO8)  
{ LS
ewMj  
return sFileName; pK`1pfih  
} WX"iDz.  
r<'ni  
A]0A
,A0  
public void setSFileName(String value) &10l80vj  
{ _{j'` #  
sFileName = value; Z2n Jw  
} k+9*7y8w  
/q|r!+  
`wI$  
public int getNSplitter() jej.!f:H  
{ V52>K$j  
return nSplitter; @JW HG1qJ  
} (g"
{A  
&f=O`*I'+!  
NS<C"O  
public void setNSplitter(int nCount) :1*q}R   
{ 26M:D&|ZB  
nSplitter = nCount; aE|'%72g  
} TxJoN]Z.  
} 1`hmD1d  
oX=dJJE  
v~8CpC  
/* 8F>u6Y[P  
**Utility.java
(Q5rOrA"  
*/ .7K)'  
package NetFox; &9Y ^/W  
<`$svM  
mpr_AL!ZO~  
public class Utility { epicY  
}b5omHUE%  
y^!>'cdV  
public Utility() YD3jP}Ym  
{ V0)bPcS/  
^C=dq(i=[  
2LfiaHO  
} z`"*60b  
jgvzp  
//线程睡眠 X<%`  
public static void sleep(int nSecond) K}t=Y  
{
agV z  
try{ RWg'W,v=!  
Thread.sleep(nSecond); /^]/ iTg  
} Ux,?\Vd  
catch(Exception e) sYEh>%mo^C  
{ 8Y]% S9.  
e.printStackTrace (); qX[{_$^Q  
} Y/x>wNW  
} zG0]!A  
a}e GB +  
//日志 F50l->F2&  
public static void log(String sMsg) Pz^C3h$5_  
{ b(IZ
:ekZ5  
System.err.println(sMsg); (himx8Uml2  
} <x8I<K  
&4O2uEW0  
3F?7oMNIh  
public static void log(int sMsg) 5cvvdO*C0  
{ p4F%FS:`  
System.err.println(sMsg); xH\!j  
} eJ*u]GH U  
} t$Bu<frQ  
q+znb'i-x  
8(Cs<C!  
/* KqN;a i,F  
**TestMethod.java 4U8N7  
*/ eRqPZb"6MR  
package NetFox; J$W4AT  
vbD""  
"S]G+/I|iw  
public class TestMethod { kwXUjnp  
$>8O2p7W  

>\!G43Q=  
public TestMethod() /Rf,Rjs  
{ ///xx/weblogic60b2_win.exe (@1>G ^%  
try{ CnpQdI  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); lak,lDt]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); %[4u #G`  
SiteFileFetch fileFetch = new SiteFileFetch(bean);  bUsX~R-  
fileFetch.start(); *rg
F[ :  
} y6dQ4Whv&  
catch(Exception e){e.printStackTrace ();} iT;Ld $!{f  
+7Uv|LZ~@  
 0ijYE  
} %aI,K0\  
i z
YC0T9  
ken.#>w  
public static void main(String[] args)  Y(  
{ yH(3 m#  
new TestMethod(); q@G}Hjn  
} bv;.6C(T<  
} v.-r %j{I  
点击下载更多相关资料