http断点续传简单实现（java)

/* O
m\vMd@!  
**SiteFileFetch.java *vxk@`K~  
*/ Hg izW  
package NetFox; zu{P#~21  
import java.io.*; ,!y$qVg'\f  
import java.net.*; G4X|Bka  
#OD/$f_  
,m:.-iy?  
public class SiteFileFetch extends Thread { & l&:`nsJ  
)9`qG:b'  
,T$U'&;  
SiteInfoBean siteInfoBean = null; //文件信息Bean BM .~ 5\  
long[] nStartPos; //开始位置 JIOR4'9  
long[] nEndPos; //结束位置 06Sceq  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .j0$J\:i  
long nFileLength; //文件长度 aP+X}r  
boolean bFirst = true; //是否第一次取文件 [EXs  
boolean bStop = false; //停止标志 [D4SW#  
File tmpFile; //文件下载的临时信息 "$^ ~!1~  
DataOutputStream output; //输出到文件的输出流 %_W)~Pv{+  
ucW-I;"  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） kfY}S  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3$>1FoSk  
{ )_S(UVI5  
siteInfoBean = bean; Hk.TM2{w  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;))+>%SGCt  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); c9u`!'g`i  
if(tmpFile.exists ()) K!Y71_#  
{ {@{']Y  
bFirst = false; Vaw+.sG`AP  
read_nPos(); XJ| <?  
} 9F;>W ET  
else 6}Ci>_i4#  
{ 37.S\gO]  
nStartPos = new long[bean.getNSplitter()]; K;H&n1  
nEndPos = new long[bean.getNSplitter()]; YfKdR"i+.  
} nT$SfGFj8  
WO>nIo5Y  
D8?Vn"  
s$`0yGmQ  
} CxW>~O:  
c]o'xd,T8\  
T_5H&;a  
public void run()
kv{za4,&  
{
mL{6L?  
//获得文件长度 vw/J8'  
//分割文件 ^A&1^B  
//实例FileSplitterFetch q{LF>Wi  
//启动FileSplitterFetch线程 G}raA%  
//等待子线程返回 Z0", !6nS  
try{ R.1.
)P[  
if(bFirst) +lcbi  
{ 4p;`C  
nFileLength = getFileSize(); :J&oX <nF^  
if(nFileLength == -1) qt"m  
{ MH\dC9%p  
System.err.println("File Length is not known!"); \V
~eVf;~  
} Moza".fiN  
else if(nFileLength == -2) j>"@,B g*  
{ `l[c_%Bm  
System.err.println("File is not access!"); .?sx&2R2  
} !M1"b;  
else 3,qr-g|;jM  
{ ;$wVu|&  
for(int i=0;i<nStartPos.length;i++) !?h;wR  
{ >SHhAEF  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ul>3B4  
} ?1 4{J]H4  
for(int i=0;i<nEndPos.length-1;i++) K Z91-  
{ Cnh \%OW  
nEndPos = nStartPos[i+1]; )F]]m#`  
} E]-/Zbvdv  
nEndPos[nEndPos.length-1] = nFileLength; >}i E(  
} hnhd{$2Z  
} JjTegQN  
e6$WQd`O  
<`r>h  
//启动子线程 M!^az
[[  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 5Yq@;e  
for(int i=0;i<nStartPos.length;i++) cR<fJ[*  
{ BW*rIn<?G  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), tg4pyW<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), W[e$>yK  
nStartPos,nEndPos,i); Eo]xNn/g  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); v PG},m~-  
fileSplitterFetch.start(); hhc,uJ">!  
} R-d:j^:f  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7ZWgf"1j  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); y766; X:J  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", lq;Pch  
nEndPos = " + nFileLength);
.}~_a76  
// fileSplitterFetch[nPos.length-1].start(); v`Oc,  
c,+:i1IAy  
'I6i,+D/q  
//等待子线程结束 z<XtS[ki
 
//int count = 0; ,w4V?>l  
//是否结束while循环 h J)h
\  
boolean breakWhile = false; -gX1-,dE  
#c.K/&Gc7j  
E{P|)`,V  
while(!bStop) w%jII{@,  
{ Txb#C[`  
write_nPos(); ]jp6k<KF  
Utility.sleep(500); M!D3}JRm  
breakWhile = true; Y&Z.2>b
 

GH$pKB  
f(y:G^V  
for(int i=0;i<nStartPos.length;i++) S3Xl  
{ 'e'cb>GnA  
if(!fileSplitterFetch.bDownOver) @<EO`L)Z  
{ {fT6O&br  
breakWhile = false; Z o(rTCZX  
break; z5*'{t)  
} JOeeU8C  
} 1?+St`+{B-  
if(breakWhile) @Qt{jI!  
break; $}<e|3_  
N2<!}Eyu  
_g"<UV*H  
//count++; i2SR{e8:GF  
//if(count>4) H9Q&tl9  
// siteStop(); '3^'B03  
} *_\_'@1|J)  
oV78Hq6  
>e5qv(y]  
System.err.println("文件下载结束！"); a~y'RyA  
} "b3"TPfK  
catch(Exception e){e.printStackTrace ();} G mA< g  
} ee76L&:  
DT&@^$?  
|[b{)s?x  
//获得文件长度 7a<DKB  
public long getFileSize() Fd9[pU  
{ 0*{%=M  
int nFileLength = -1; )|#sfHv7  
try{ b,1ePS  
URL url = new URL(siteInfoBean.getSSiteURL()); ,/|T-Ka
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); m#\dSl}  
httpConnection.setRequestProperty("User-Agent","NetFox"); bq0zxg%  
)irEM  
'YSHi\z ](  
int responseCode=httpConnection.getResponseCode(); z9Rp`z&`E  
if(responseCode>=400) U9MxI%tb  
{ ((M>s&\y*Y  
processErrorCode(responseCode); $kp{Eg '  
return -2; //-2 represent access is error ;vjOUn[E  
} V1B5w_^>h'  
p9{mS7R9T  
>(t6.=  
String sHeader; 89(Q1R ?:  
ds[|   
d
5:c^`  
for(int i=1;;i++) 9V*qQS5<p  
{ /hyN;.hpOO  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); *VxgARIL  
//Utility.log(in.readLine()); i?^L/
b`H  
sHeader=httpConnection.getHeaderFieldKey(i); =U?dbSf1*  
if(sHeader!=null) $*=<Yw
4  
{ >}6%#CAf  
if(sHeader.equals("Content-Length")) wNdisI  
{ PB\x3pV!}  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); u.xnOcOH!  
break; s
?L  
} B:'US&6Lf'  
} 1#+S+g@#  
else YS"=yye3e  
break; v):Or'$~M  
} ji0@P'^;  
} Q*~]h;6\{d  
catch(IOException e){e.printStackTrace ();} z!9-
:  
catch(Exception e){e.printStackTrace ();} Vs!Nmv`  

.eVG:tl\  
t
;\Y{`  
Utility.log(nFileLength); XU(eEnmom  
P( 8OQL:  
Qq|57X)P*  
return nFileLength; f(MO_Sj]  
} Q hO!Ma]  
YT(AUS5n  
BLD gt~h#  
//保存下载信息（文件指针位置） V1M.JU  
private void write_nPos() +@wDqc  
{ %n9aaoD  
try{ vUM4S26"NT  
output = new DataOutputStream(new FileOutputStream(tmpFile)); >pe.oxY  
output.writeInt(nStartPos.length); zIAD9mQex  
for(int i=0;i<nStartPos.length;i++) ;u)I\3`*!  
{ A2Gevj?F$  
// output.writeLong(nPos); 7hPY_W y  
output.writeLong(fileSplitterFetch.nStartPos); *gWwALGo5  
output.writeLong(fileSplitterFetch.nEndPos); [.wYdv35  
} vy
I!]p  
output.close(); 11;MN  
} #AQV(;r7@  
catch(IOException e){e.printStackTrace ();} /IMFO:c  
catch(Exception e){e.printStackTrace ();} 0n{=%Q  
} h~zT ydnH  
Ig>(m49d  
Er?&Y,o  
//读取保存的下载信息（文件指针位置） r_A$DaC]  
private void read_nPos() vx5Zl&6r  
{ TOQP'/   
try{ c{w2Gt!  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); qlP
T
Ll  
int nCount = input.readInt(); 0LJv'  
nStartPos = new long[nCount]; FU4L6n  
nEndPos = new long[nCount]; '^UI,"Ti  
for(int i=0;i<nStartPos.length;i++) )lDD\J7  
{ IjnU?Bf  
nStartPos = input.readLong(); 92oFlEJ  
nEndPos = input.readLong(); 8KzkB;=n  
} lrIe"H@  
input.close(); 5:_}zu|!u  
} e+fN6v5pU  
catch(IOException e){e.printStackTrace ();} NK H@+,+V  
catch(Exception e){e.printStackTrace ();} C$`tbq  
} 3/eca  
/N.U/
MPL_  
5`p.#  
private void processErrorCode(int nErrorCode) \qJXF|z<K  
{ d8P^lv*rQW  
System.err.println("Error Code : " + nErrorCode); |P?*5xPB  
} `r 3  
.(k|wX[Fu~  
%d9uTm;  
//停止文件下载 eTcd"Kd/  
public void siteStop() S3Jo>jXS "  
{ {E|$8)58i  
bStop = true; (TT}6j  
for(int i=0;i<nStartPos.length;i++) \ @2R9,9E  
fileSplitterFetch.splitterStop(); +ami?#Sz*;  
DZtsy!xA  
[ub e6  
} a0H+.W+]  
} 67FWa  
//负责部分文件的抓取 7WzxA=*#  
**FileSplitterFetch.java )zDCu`  
*/ /Lr.e
%  
package NetFox; +9sQZB# (  
[j+sC*  
l9Q-iJ  
import java.io.*; _7_Y={4=`  
import java.net.*; MkXmA`cP  
3F^Q51:t  
iuul7VR-%  
public class FileSplitterFetch extends Thread { 'i|YlMFIg  
>Y@H4LF;1x  
nKj7.,>;:<  
String sURL; //File URL Q^^niVz  
long nStartPos; //File Snippet Start Position tw)mepwB  
long nEndPos; //File Snippet End Position ^E>3|du]O  
int nThreadID; //Thread's ID -X6PRE5a2  
boolean bDownOver = false; //Downing is over 5~DJWi,  
boolean bStop = false; //Stop identical Xne1gms  
FileAccessI fileAccessI = null; //File Access interface dft!lBN  
)J(6xy  
S~G]~gt  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException q{x8_E!L  
{ jT;;/Fd3/  
this.sURL = sURL; n|yO9:Uw<  
this.nStartPos = nStart; <<O$ G7c  
this.nEndPos = nEnd; .O<obq~;C  
nThreadID = id; -M#Wt`6A  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $M:*T.3  
} C\hM =%  
i SQu#p@  
B&"Q\'c  
public void run() {R{=+2K!|k  
{ _Y m2/3!  
while(nStartPos < nEndPos && !bStop) v4 E}D  
{ 6Q5^>\Y  
X1_5KH  
Bk{]g=DO  
try{ vtJJ#8a]  
URL url = new URL(sURL); SUK?z!f<i  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lPAQ3t!,  
httpConnection.setRequestProperty("User-Agent","NetFox"); SSzIih@u  
String sProperty = "bytes="+nStartPos+"-"; E2+`4g@{8<  
httpConnection.setRequestProperty("RANGE",sProperty); Qn2&nD%zi  
Utility.log(sProperty); buHJB*?9  
$3kH~3{]  
7F~X,Dk_  
InputStream input = httpConnection.getInputStream();
<9b&<K:  
//logResponseHead(httpConnection); es0hm2HT3  
V>3X\)qu  
XQw9~$  
byte[] b = new byte[1024]; )0k53-h&  
int nRead; }c:M^Ff  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) E=O\0!F|b  
{ [dVL&k<P  
nStartPos += fileAccessI.write(b,0,nRead); bpa?C  
//if(nThreadID == 1) <(!:$  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |k00Z+O(  
} z\4.Gm-  
`uTmw^pZX  
1G`Pmh@  
Utility.log("Thread " + nThreadID + " is over!"); f* wx<  
bDownOver = true; fI|$K)K  
//nPos = fileAccessI.write (b,0,nRead); p5*jz
Q  
} 4?01s-Y  
catch(Exception e){e.printStackTrace ();} |JsZJ9W+J  
} _,*r_D61S  
} `kS
ZX:=};  
`XDl_E+>l  
RT8 ?7xFc  
//打印回应的头信息 G^@5H/)  
public void logResponseHead(HttpURLConnection con) 9W);rL|5  
{ 7a}k  
for(int i=1;;i++) bvOq5Q6
 
{ + >!;i6|  
String header=con.getHeaderFieldKey(i); b\,+f n  
if(header!=null) y8xE 6i  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )QJUUn#  
Utility.log(header+" : "+con.getHeaderField(header)); (**oRwr%  
else ]eV8b*d6  
break; K:WDl;8(d  
} -D:b*D  
} 1{.9uw"2S  
X5w$4Kj&4l  
JlJ a #  
public void splitterStop() o5)<$P43  
{ e+=K d+:k  
bStop = true; iN.n8MN=I  
} $<OD31T  
tQ601H>o  
!H\F2Vxs  
} ~F#j#n(=`q  
^=*;X;7  
]I6 J7A[  
/* 4mbBmQV$#  
**FileAccess.java u$`a7Lp,n  
*//文件访问(定位，写) !PE]C!*gv&  
package NetFox; 1AFA=t:]p  
import java.io.*; 2 ? 4!K.  
dD@(z:5M\  
GKeU%x
 
public class FileAccessI implements Serializable{ c1gQ cqF  
U%/+B]6jP  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 '0,^6'VWOV  
RandomAccessFile oSavedFile; 2+WaA,   
long nPos; H6gSO(U  
23jwAsSo  
OcO3v'&  
public FileAccessI() throws IOException iJ|uvPCE  
{ Y|/ 8up  
this("",0); VS|2|n1<6  
} DIUjn;>k8  
o,wUc"CE  
\^1E4C\":  
public FileAccessI(String sName,long nPos) throws IOException . 'yCw#f  
{ $`'/+x"%  
oSavedFile = new RandomAccessFile(sName,"rw"); M'l ;:  
this.nPos = nPos; OB}Ib]  
oSavedFile.seek(nPos); bQ5\ ]5M  
} Ht&YC<X  
&>}5jC.I  
I*^Ta{j[  
public synchronized int write(byte[] b,int nStart,int nLen) ,wPr"U+7  
{ ~bpgSP"
 
int n = -1; r@,2E6xn  
try{ ]]Ufa
s9  
oSavedFile.write(b,nStart,nLen); %N_%J
K\{@  
n = nLen; {fp[BF  
} uvS)
8-o&F  
catch(IOException e) E<*xx#p  
{ C9 j|OSgk  
e.printStackTrace (); YA5g';$H*  
} ,v}k{( 16{  
[1H^3g '  
-|9=P\U8S  
return n; \lNN Msd&  
} v(%*b,^  
-H-~;EzU  
rU(+T0t?I  
} 0Y5_PTWb+Y  
S0W||#Pr  
BfiD9ka-z  
/* UR5`ue ;  
**SiteInfoBean.java ;xn0;V'=  
*/ J4U1t2@)9  
package NetFox; 2I{"XB  
Oa>Ppldeg  
mB)bcuPv  
public class SiteInfoBean { 1m0c|ckb  
Z<{QaY$"  
is@?VklnB  
private String sSiteURL; //Site's URL 5Jnlz@P9  
private String sFilePath; //Saved File's Path E&:,oG2M  
private String sFileName; //Saved File's Name I1&aM}y{G  
private int nSplitter; //Count of Splited Downloading File MnW+25=N  
k$}fWR  
#A8sLkY  
public SiteInfoBean() *}W_+qo"  
{//nSplitter的缺省值为5 Jj%K=
sw  
//default value of nSplitter is 5
""
~ajy  
this("","","",5); Yu2Bkq+  
} Ny)X+2Ae  
C+&l< fM&  
DLNbo2C  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) jb!i$/%w  
{ ~4cC/"q$X  
sSiteURL= sURL; {H'Y
`+  
sFilePath = sPath; o*hF<D$Y  
sFileName = sName; b5n'=doR/I  
this.nSplitter = nSpiltter; lsNd_7k  
-d:Jta!}{  
kylVH! @l  
} FJ?IUy 6  
Q#zmf24W  
_v]MsT-q  
public String getSSiteURL() \xoP)Ub>  
{ 0#^v{DC  
return sSiteURL; <1M-Ro?5k  
} Aq7osU1B  
@7n"yp*"  
j"Pv0tehw  
public void setSSiteURL(String value) h@@=M  
{ Jxm.cC5z.  
sSiteURL = value; NQ2E  
} FzC'G57Kl  
~61v5@  
~W]TD@w  
public String getSFilePath() +=8VTCn?  
{ l1Fc>:o{  
return sFilePath; M
\Kx'N  
} m`r(p"  
3=ymm^  
u> 7=AlWF-  
public void setSFilePath(String value) 9'q*:&qq  
{ UFuX@Lu0  
sFilePath = value; $iz|\m  
} &@YmA1Yu)E  
3? +H
d  
{Y9q[D'g.  
public String getSFileName() '2^Q1{ :\  
{ H<N,%G  
return sFileName; i K? w6  
} Pgea NK5Y  
cYt!n5w~W  
pz>>)c`  
public void setSFileName(String value) 4HA<P6L  
{
A3@6N(  
sFileName = value; cExS7~*  
} *;*r8[U}q  
rw #$lP  
J-hbh  
public int getNSplitter() &:)Wh[  
{ 83q6Sv  
return nSplitter; ^y%T~dLkp'  
} n.0fVV-A  
R
~$qo)v  
V~5jfcd  
public void setNSplitter(int nCount) aw42oLk  
{ 4r}8lpF_(  
nSplitter = nCount; D,FkB"ZZE  
} BThrO d  
} ?5 7Sk+  

I2 P@L?h  
D d</`iUq  
/* 9q[oa5INd  
**Utility.java uW36;3[f#1  
*/ w+CA1q<  
package NetFox; n7-6- #  
^r
,=vO  
y h9*z3  
public class Utility { 9qG6Pb  
Jg|XH L)  
emN*l]N  
public Utility() S|`o]?nc>  
{ dlTt_.  
)hfpwdQ  
oM
`0y@QCf  
} L/G6Fjg^  
~IN>3\j  
//线程睡眠 `+Q%oj#FF  
public static void sleep(int nSecond) ]GQG~H^  
{ Q$@I"V&G.  
try{ 9zy!Fq  
Thread.sleep(nSecond); a!AA]  
} SI-Ops~e  
catch(Exception e) jtc]>]6i  
{ NHZz _a=  
e.printStackTrace (); W9GVt$T7  
} %d<"l~<5;  
} 7O-x<P;  
_zi|  
//日志 WEi2=3dV  
public static void log(String sMsg) 0Z{ZO*rK  
{ ~FG]wNgS  
System.err.println(sMsg); nc|p)  
} G*P#]eO  
^3L0w
}#  
cHt#us  
public static void log(int sMsg) |_@>*Vmg  
{ IB]l1<  
System.err.println(sMsg); j+ 0I-p  
} VS8Rx.?  
} ^,T(mKS  
}?Ai87-{  
-C?ZB}`   
/* L0WN\|D  
**TestMethod.java b!5~7Ub.No  
*/ XuM'_FN`A<  
package NetFox; 2!=f hN
 
*YuF0Yt  
9m~p0ILh  
public class TestMethod { *wB1,U{  
5taT5?n2  
e h?zNu2=  
public TestMethod() vT,AMja  
{ ///xx/weblogic60b2_win.exe mSh[}%swj  
try{ PBTnIU  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); JYbL?N  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Vb]=B~^`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ={@6{-tl  
fileFetch.start(); D7Q$R:6|  
} +}os&[S  
catch(Exception e){e.printStackTrace ();} UhQj Qaa~  
UJ')I`zuI  
?QdWrE_  
} PP33i@G  
@YTaSz$L  
9 X`Sm}i  
public static void main(String[] args) fN1-d&T  
{ Wf>R&o6tr  
new TestMethod(); 68C%B9.b'  
} 5f K_Aq{  
} naz
Z*lC  
点击下载更多相关资料