http断点续传简单实现（java)

/* s E;2;2u"  
**SiteFileFetch.java 8VC%4+.FF  
*/ Qx_N,1>S  
package NetFox; TnQW~_:  
import java.io.*; l701$>>  
import java.net.*; w")m]LV  
? YluX  
80Q%c(i  
public class SiteFileFetch extends Thread { K=pG,[ChA  
^nD
a-J$  
~4mRm!DP  
SiteInfoBean siteInfoBean = null; //文件信息Bean Ua~8DdW  
long[] nStartPos; //开始位置 7d+0'3%  
long[] nEndPos; //结束位置 /1Ss |.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 v0T?c53?  
long nFileLength; //文件长度 xokA_3,1F  
boolean bFirst = true; //是否第一次取文件 t{`krs``  
boolean bStop = false; //停止标志 /neY2D6  
File tmpFile; //文件下载的临时信息 6 tB\X^  
DataOutputStream output; //输出到文件的输出流 bwJluJ,E  
E[BM0.#bZ  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Q~KzcB<  
public SiteFileFetch(SiteInfoBean bean) throws IOException } na@gn  
{ S5YEz XG  
siteInfoBean = bean; iI &z5Q2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]c]^(C  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 3/]~#y%2  
if(tmpFile.exists ()) _p^Wc.[~M  
{ _!w69>Nj  
bFirst = false; 9Q7342  
read_nPos(); Zvr
a >%  
} Kb'4W-&u!  
else hb9HVj  
{ 0vMKyT3 c  
nStartPos = new long[bean.getNSplitter()]; vTL/% SJ8  
nEndPos = new long[bean.getNSplitter()]; `_BmVms  
} as!P`*@  
GXRW"4eF5  
sN) xNz  
RS@G.|  
} aadw#90  
uh>"TeOi  
@CoUFdbz  
public void run() ~~Rq
$'q}  
{ a :cfr*IsK  
//获得文件长度 1{1mL-I;  
//分割文件 9Sl5jn  
//实例FileSplitterFetch ^ q3H  
//启动FileSplitterFetch线程 *nv^s  
//等待子线程返回 CdtCxy5  
try{ /-(OJN5F^  
if(bFirst) ,jl4W+s  
{ vN~joQ=d  
nFileLength = getFileSize(); JgV4-B0  
if(nFileLength == -1) 9hJ  a K  
{ ZkNet>9  
System.err.println("File Length is not known!"); 4ti,R'  
} U r8JG&,  
else if(nFileLength == -2) k?1e+ \  
{ y'z9Ya  
System.err.println("File is not access!"); _94R8?\_V7  
} w$""])o,  
else
$4^h>x  
{ \XfLTv  
for(int i=0;i<nStartPos.length;i++) JbN,K  
{ f'BmIFb#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); P0k.\8qz  
} Os!x<r|r  
for(int i=0;i<nEndPos.length-1;i++) 1@F>E;YjL=  
{ X?(R!=a  
nEndPos = nStartPos[i+1]; "I@akM$x  
} -KZ9TV # R  
nEndPos[nEndPos.length-1] = nFileLength; u(PUbxJ
V  
} xlh<}Vtp  
} K~fWZT3]  
xU(b:D Z  
st>%U9  
//启动子线程 \tP*Pz  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; NceK>::56  
for(int i=0;i<nStartPos.length;i++) AKS. XW  
{ |:SIyXGbY  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^S)t;t@x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 7ZUS  
nStartPos,nEndPos,i); ~NO7@muw  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1O1MB&5%  
fileSplitterFetch.start(); -$,'|\Y  
} Owv}lJ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), WHu[A/##']  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); JIf.d($ ~:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8x8nQ*_  
nEndPos = " + nFileLength); ll?Qg%V[t  
// fileSplitterFetch[nPos.length-1].start(); Nk1p)V SC  
PO|gM8E1x?  
cE?p~fq<  
//等待子线程结束 r[#*..Y  
//int count = 0; ?KE:KV[Y  
//是否结束while循环 L(C0236r  
boolean breakWhile = false; f>m! }F:  
#IJ6pg>K  
X+/^s)  
while(!bStop) \KKE&3=  
{ ~y/qm [P  
write_nPos(); "#h/sAIs  
Utility.sleep(500); `1#Z9&bO  
breakWhile = true; 9"}5jq4*  
:W+%jn  
)q[Wzx_ j<  
for(int i=0;i<nStartPos.length;i++) s%A?B8,  
{ aPX'CG4m  
if(!fileSplitterFetch.bDownOver) 14(ct  
{ v|@EuN14<  
breakWhile = false; 6w_TL<S  
break; U}l=1B  
} at\$ IK_  
} urQ<r{$x0  
if(breakWhile) zXkq2\GHA  
break; k4` %.;  
i1GQ=@  
P~PM$e  
//count++; f9O_M1=|lo  
//if(count>4) |\)Y,~;P  
// siteStop(); a|k*A&5u2  
} u_b6u@r7  
n;>
r  
FS*J8)  
System.err.println("文件下载结束！");
" ^!=e72  
} KbH|'/w  
catch(Exception e){e.printStackTrace ();} vorb?iVf>  
} Gsz$H_  
o<5+v^mt#  
wBEBj7(y  
//获得文件长度 j#YVv c%  
public long getFileSize() V}JBv$+ko  
{ PeSTUR&  
int nFileLength = -1; Vw`%|x"Xz  
try{ th5UzpB4  
URL url = new URL(siteInfoBean.getSSiteURL()); *r|13|k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #fXy4iL l  
httpConnection.setRequestProperty("User-Agent","NetFox"); %2^V.`0T  
K1o&(;l8G  
"5<YN#  
int responseCode=httpConnection.getResponseCode(); :zpT Gk8Z  
if(responseCode>=400) "kKIv|`  
{ 7>EMr}f C  
processErrorCode(responseCode); ]jR-<l8I-  
return -2; //-2 represent access is error 8[a N5M]  
} v7D0E[)~  
g<:TsP'|  
N1U.1~U  
String sHeader; 'H
u+8,xA  
ciW;sK8  
d-gcXaA-8  
for(int i=1;;i++) SUL\|z`5  
{ oq(W|  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); @scSW5+  
//Utility.log(in.readLine()); ?gjkgCbC#  
sHeader=httpConnection.getHeaderFieldKey(i); >VG*La'c  
if(sHeader!=null) q}(f9  
{ 8A'SMJi  
if(sHeader.equals("Content-Length")) 8sq0 BH  
{ 8SCXA9}  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); -.
Zy(  
break; y-Lm^GW4  
} J?jxD/9Yb  
} _J,*0~O$  
else Jt)J1CAYo  
break; F'ez{B\AX  
} N_(-\\mq  
} VuH}@  
catch(IOException e){e.printStackTrace ();} tn|H~iF{  
catch(Exception e){e.printStackTrace ();} khQfLA  
`'pfBVBz  
m=w #l>!  
Utility.log(nFileLength); 'a~F'FN$  
JYLAu4s6  
vpdT2/F  
return nFileLength; ,,?XGx  
} p.,`3"C1  
P|a|4Bb+fW  
d-I=xpB  
//保存下载信息（文件指针位置） ifmX<'(9A  
private void write_nPos() *#GX~3A  
{ _# &_`bZH  
try{ %xC}#RDf  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6f+@@=Xc  
output.writeInt(nStartPos.length); !)`m mr  
for(int i=0;i<nStartPos.length;i++) WGUd@l
C~  
{ HLqDI
lL  
// output.writeLong(nPos); )?(_vrc<  
output.writeLong(fileSplitterFetch.nStartPos); SN$3cg]z  
output.writeLong(fileSplitterFetch.nEndPos); ,5x9o"N!  
} yEVnG` 1  
output.close(); <4I`|D3@  
} E:P_CDSd]  
catch(IOException e){e.printStackTrace ();} UUvR>5@n  
catch(Exception e){e.printStackTrace ();} k7 Ne(4P  
} xzf/W+.>.  
~e5E%bXxC  
e_FoN
T  
//读取保存的下载信息（文件指针位置） 
6g)CpZU  
private void read_nPos() @2+'s;mUV  
{ WHRBYq_  
try{ 02^Nf
7DMR  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;rXZ?"  
int nCount = input.readInt(); uzS;&-nA  
nStartPos = new long[nCount]; tHFUV\D;,  
nEndPos = new long[nCount]; EIOP+9zP  
for(int i=0;i<nStartPos.length;i++) C`8.8  
{ k?_uv  
nStartPos = input.readLong(); k:&B b"  
nEndPos = input.readLong(); ]'z 5%'  
} "}0)~,{xB  
input.close(); Ls&-8  
} -R`nitf  
catch(IOException e){e.printStackTrace ();} Y{8}z ZD  
catch(Exception e){e.printStackTrace ();} $$'[%  
} FyV $`c$  
!]&+g'aC3  
] B>.}  
private void processErrorCode(int nErrorCode) ~hT(uxU/  
{ A=np?
wc  
System.err.println("Error Code : " + nErrorCode); 6L-3cxqf\  
} o\nFSGkn  
-I~\  
o9Tsyjbj  
//停止文件下载 :T#f&|Gg;  
public void siteStop() Mp@dts/|  
{ =ibKdPtTh^  
bStop = true; L; <Pod  
for(int i=0;i<nStartPos.length;i++) IkQ,#Bsb[  
fileSplitterFetch.splitterStop(); hh-sm8  
'Ojxzz*tT  
|8akp  
} Iz!]LW  
} Q%0 N\  
//负责部分文件的抓取 M[0NB2`Wp  
**FileSplitterFetch.java 9]|C$;kw@  
*/ > v4+@o[~  
package NetFox; %'Z`425a  
D<T:UJ  
E/^N   
import java.io.*; 9o
l&p>  
import java.net.*; 9]g`VD6<v  
6N/6WrQEeg  
*tl;0<n  
public class FileSplitterFetch extends Thread { ",S146Y+  
K>#QC  
tl=e!  
String sURL; //File URL D+Z2y1
  
long nStartPos; //File Snippet Start Position i8=+<d  
long nEndPos; //File Snippet End Position <qBM+m$|)  
int nThreadID; //Thread's ID xqv&^,ic  
boolean bDownOver = false; //Downing is over $/Llzpvny  
boolean bStop = false; //Stop identical w[u>*I  
FileAccessI fileAccessI = null; //File Access interface 5#dJga/88  
\ns} M3  
_*wlK;`  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )J 8mn*  
{ (b7',:_U7  
this.sURL = sURL; iz27yXHZ~  
this.nStartPos = nStart; v `;Hd8  
this.nEndPos = nEnd; 9{-H/YS\_s  
nThreadID = id; h~ehZJys  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ,be$~7qS  
} @CKMJ^#|  
q( %)^C  
RvyCc!d  
public void run() HgTBON(  
{ XM`&/)  
while(nStartPos < nEndPos && !bStop) B3E}fQm )  
{ yB4eUa!1  
GGsAisF"N  
MKX58y{+  
try{ s6Il3Kf  
URL url = new URL(sURL); `X(H,Q}*;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )c<[@::i  
httpConnection.setRequestProperty("User-Agent","NetFox"); /Nhc|x6zQ  
String sProperty = "bytes="+nStartPos+"-"; *b"aJ<+  
httpConnection.setRequestProperty("RANGE",sProperty); V%voe  
Utility.log(sProperty); E=ObfN"ge  
"!:)qVL^  
tV2o9!N4  
InputStream input = httpConnection.getInputStream(); !#PA#Q|cO  
//logResponseHead(httpConnection); (Y  
MSe>1L2=  
AH^ud*3F  
byte[] b = new byte[1024]; IB^vEY!`6_  
int nRead; S)`@)sr  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .RWq!Z=)3  
{ aX*7tRn_%  
nStartPos += fileAccessI.write(b,0,nRead); $]4o!Z  
//if(nThreadID == 1) +9.GNu  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y]
uBVn'u  
} !14l[k+\  
">q?(i\  
P&*e\"{  
Utility.log("Thread " + nThreadID + " is over!"); 'wo}1^V  
bDownOver = true;  X*`b}^T  
//nPos = fileAccessI.write (b,0,nRead); 6Z;D`X,5  
} "||' -(0  
catch(Exception e){e.printStackTrace ();} Rpxg 5  
} {#z[iiB  
} fbJa$  
Eg1|Kg\&  
)IKqO:@  
//打印回应的头信息 !#S"[q  
public void logResponseHead(HttpURLConnection con) XLlJ|xhY-K  
{ P8 R^46  
for(int i=1;;i++) VYQ]?XF3i  
{ w=[ITQ|W%  
String header=con.getHeaderFieldKey(i); 4Dasj8GsV  
if(header!=null) L8KaK  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); A%~t[
H  
Utility.log(header+" : "+con.getHeaderField(header)); "P$')uwE  
else jOL=vG  
break; lN_b&92  
} gj82qy\:  
} 0RN7hpf&`  
J5}?<Dd:  
Z*.rv t  
public void splitterStop() Q>TNzh  
{ +#6f)H(P]  
bStop = true; R xc  
} G9CL}=lJ,  
`*cJc6  
0<nW nD,z  
} |wuN`;gc"  
&0OH:P%  
q'%!qa+  
/* a4",BDx  
**FileAccess.java G'Uq595'-  
*//文件访问(定位，写) 7/dp_I}cO  
package NetFox; b6'ZVB  
import java.io.*; afjEN y1  
\<\147&)r  
sfsK[c5bm  
public class FileAccessI implements Serializable{ 2]H?q!l!O  
Xet} J@C  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 T^Hq 5Oy  
RandomAccessFile oSavedFile; VA%4ssy  
long nPos; O)`ye5>v  
8cj}9}k  
ngzQVaB9  
public FileAccessI() throws IOException dDl_Pyg4K  
{ cp
x:4R,  
this("",0); U \jFB*U  
} 0VIR=Pbp  
vSk1/  
DOq"=R+  
public FileAccessI(String sName,long nPos) throws IOException DK#Tr: 7  
{ QV _aM2  
oSavedFile = new RandomAccessFile(sName,"rw"); _w7yfZLv+  
this.nPos = nPos; h-\+# .YP  
oSavedFile.seek(nPos); UhSaqq  
} 5w</Ga  
9dp1NjOtAc  
#YSFiy:+r_  
public synchronized int write(byte[] b,int nStart,int nLen) }jYVB|2  
{ isz-MP$:K5  
int n = -1; @y,>cDg  
try{ #W/ATsDt  
oSavedFile.write(b,nStart,nLen); jr^btVOI#\  
n = nLen; ty8E;['  
} "4.A@XsY  
catch(IOException e) ![m6$G{y  
{ ephvvj~zW4  
e.printStackTrace (); &Vg)/t;  
} [2z >8SL  
HcHwvf6y  
VRUA<x  
return n; JC7:0A^  
} P@U2Q%\  
l$C Y gm  
*Q;?p
hr  
} ;;Jx1Q  
Pe`jNiI  
`Yyi;!+0  
/*  `dIwBfg_  
**SiteInfoBean.java aX.//T:':?  
*/ tQ`|MO&o  
package NetFox; H1$n6J  
l<yYfGO  
Oki{)Ssy  
public class SiteInfoBean { "fu@2y4^  
Gl9,!"A  
I~,bZA  
private String sSiteURL; //Site's URL _B
G7JvI  
private String sFilePath; //Saved File's Path ~zQxfl/  
private String sFileName; //Saved File's Name xU |8.,@  
private int nSplitter; //Count of Splited Downloading File {6>$w/+~  
)-\qo#0l  
-K6y#O@@  
public SiteInfoBean() -6# _t  
{//nSplitter的缺省值为5 ~g*5."-i  
//default value of nSplitter is 5 ;G*)7fi  
this("","","",5); ]qiX"<s>~C  
} `{Fz  
igF<].'V  
0*6Q8`I  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) FPu$Nd&\  
{ Tj!rAMQk  
sSiteURL= sURL; ~F>'+9?Sn  
sFilePath = sPath; fPG3$<Zr  
sFileName = sName; WpC9(AX5g  
this.nSplitter = nSpiltter; ?B<.d8i  
|?ZNGPt  
?)7UqVyq  
} 'AZ

xR4W  
J{$c|  
kT:?1w'  
public String getSSiteURL() Tb{RQ?Nw'  
{ UtHloq
(r  
return sSiteURL; @%r"7%tq>  
} n_*.i1\'w  
rGay~\  
=sk#`,,:  
public void setSSiteURL(String value) {5c]\{O?[  
{ j2mMm/kq\  
sSiteURL = value; Qki
? >j"  
} I 1Yr{(ho  
Nr`v|_U  
@IOl0db  
public String getSFilePath() i\=I` Yn+  
{ Op hD_^  
return sFilePath; -:Bgp*S  
} qpq(<  
t"YN:y8-  
#{J+BWP\o  
public void setSFilePath(String value) P[jh^!<j  
{ lz_ r  
sFilePath = value; c-4z8T#M^  
} q&^H" fF  
6I
a[`xuL  
3=%G{L16-  
public String getSFileName() CW+gZ!  
{ )#sN#ZR$  
return sFileName; j3j^cO[8v  
} {d> 6*b  
cvYKZB  
:c(#03w*C  
public void setSFileName(String value) l0tFj>q"  
{ l)V646-O,~  
sFileName = value; XY<KLO%  
} o8SP#ET"n  
\p!m/2  
l|M|;5TW  
public int getNSplitter() }Ggn2 X  
{ -jVg{f!  
return nSplitter; $_gv(&ZT  
} t<%+))b  
!(y(6u#  
Bf" ZmG9  
public void setNSplitter(int nCount) SBY0L.  
{ ^!x qOp!  
nSplitter = nCount; n%!50E6*:  
} %1)JRc  
} zbfe=J4c  
!e('T@^u6u  
Wj, {lJ,  
/* -?Cu-'  
**Utility.java ^Zlbs goZ  
*/ zR?1iV.]  
package NetFox; qipS`:TER  
{vur9L  
]-l4  
public class Utility { 2~hQ   
s:I 8~Cc  
JC}T*h>Ee  
public Utility() 6mjD@  
{ `0-i>>  
5'_:>0}  
kqGydGh*"  
} u3sr
"w&  
|V^f}5gd  
//线程睡眠 l I2UpfkBP  
public static void sleep(int nSecond) l>)+HoD  
{ %m$t'?  
try{ Ad4-aWH  
Thread.sleep(nSecond); |WW'qg]Uu  
} OOYdrv,  
catch(Exception e) 4 &0MB>m  
{
,,-j5Y  
e.printStackTrace (); M->#WGl\B  
} f|2QI~R  
} ,.&D{$1W  
3w! NTvp  
//日志 z'0 =3  
public static void log(String sMsg) S(:|S(  
{ Az/P;C=  
System.err.println(sMsg); [ *
!0DW`  
} <<H'Z  
H-8_&E?6m  
Htep
3Ol3  
public static void log(int sMsg) 1h`#H:  
{ d!"gb,ec  
System.err.println(sMsg); Z*'_/Grv?  
} z0T6a15f!P  
} qnO/4\qq  
5'EoB^`8N~  
yaAg!mW  
/* jjg&C9w T  
**TestMethod.java w# ;t$qz}  
*/ l!IN#|{(  
package NetFox; Ub[UB%(T  
OO;I^`Yn  
|2I p*  
public class TestMethod { 4hUUQ;xj  
Nl{on"il  
mHNqzdaa  
public TestMethod() ~~#/jULbV  
{ ///xx/weblogic60b2_win.exe > Qh#pn*  
try{ ,;yaYF6|/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); t<cWMx5ra  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); j0S[JpoF  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ZOL#Q+U  
fileFetch.start(); 1c`Yn:H^  
} pH0MVu(W  
catch(Exception e){e.printStackTrace ();} v&`n}lS  
^{-Z3Yxd  
&p=(0$0&-  
} +sXnC
\  
07Oagq(  
]jV1/vJ-!  
public static void main(String[] args) u<HJFGLzI  
{ [LSs|f  
new TestMethod(); qtp-w\#S$  
} C(}Kfi@6N  
} n'@XgUI,  
点击下载更多相关资料