http断点续传简单实现（java)

/* Y@#N_]oXj  
**SiteFileFetch.java yvzH}$!]  
*/ %kop
's&?C  
package NetFox; \xl$z*zI  
import java.io.*; z,E`+a;  
import java.net.*; 3)#Nc|  
#}@8(>T  
8q{|nH  
public class SiteFileFetch extends Thread { L[D+=  
{~FPvmj&  
"+7E9m6I  
SiteInfoBean siteInfoBean = null; //文件信息Bean 1:^Xd~X  
long[] nStartPos; //开始位置
r,Xyb`  
long[] nEndPos; //结束位置 XMkRYI1~  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 }0]u
A|lH*  
long nFileLength; //文件长度 [)jNy_4  
boolean bFirst = true; //是否第一次取文件 JrLh=0i9  
boolean bStop = false; //停止标志 |te=DCO  
File tmpFile; //文件下载的临时信息 _6,\;"it?8  
DataOutputStream output; //输出到文件的输出流 w|S b`eR  
3<M yb  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） (7b9irL&cn  
public SiteFileFetch(SiteInfoBean bean) throws IOException {'h&[f>zcQ  
{ v&/H6r#E.  
siteInfoBean = bean; :7"Q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;
zo|. YD  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Sa9VwVUE  
if(tmpFile.exists ()) MI(#~\Y~P  
{ *P7/ry^<F  
bFirst = false; s
iCm)B  
read_nPos(); W!O/t^H>  
}
bQq/
~  
else
Kx)PK  
{ LS9,:!$  
nStartPos = new long[bean.getNSplitter()]; I}|a7,8   
nEndPos = new long[bean.getNSplitter()]; *VJISJC  
} iEr?s-or  
ilJ`_QN  
g~.#.S ds  
*<67h*|)  
} P;z\vq<h  
C"**>OGe  
FNF`Z  
public void run() N*&T)
a  
{ \ HUDZ2 s  
//获得文件长度 j[A(@w"  
//分割文件 c?_7e9}2  
//实例FileSplitterFetch 1 /{~t[*.  
//启动FileSplitterFetch线程 h6O'"  
//等待子线程返回 !a:e=b7g  
try{ @M-w8!.~  
if(bFirst) }}]Lf3;  
{ _Y&.Nw  
nFileLength = getFileSize(); 6=$<R4B  
if(nFileLength == -1) ]j
VE
 
{ xl,% Z~[  
System.err.println("File Length is not known!"); |X A0F\  
} w5PscEc  
else if(nFileLength == -2) %(khE-SW  
{ fw,,cu`YA  
System.err.println("File is not access!"); m{RXt  
} %}zkmEY.e  
else .(cpYKFX  
{ )}N:t:rry  
for(int i=0;i<nStartPos.length;i++) .|go$}Fk  
{ [fT$# '6  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); JZxA:dg l  
} 0%L:jq{5  
for(int i=0;i<nEndPos.length-1;i++) _^(1Qb[  
{ t'At9<ib  
nEndPos = nStartPos[i+1]; y6d!?M(0U  
} YzG?K0O%  
nEndPos[nEndPos.length-1] = nFileLength; 2[pOGc$  
} 2>k*9kyp  
} 25vjn 1$sW  
(T pnJq  
v.C  
//启动子线程 "PRHQW  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8M,o)oH  
for(int i=0;i<nStartPos.length;i++) Q0jg(=9wP  
{ ]nRf%Vi8g  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 57;0,k5Gy  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5,^DT15a4P  
nStartPos,nEndPos,i); G,?a8(  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8r+u!$i!H  
fileSplitterFetch.start(); !xR9I0V5  
} p\;8?x  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %RtL4"M2j  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); zo"L9&Hzo  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", gvWgw7z  
nEndPos = " + nFileLength); /LWk>[
Z;  
// fileSplitterFetch[nPos.length-1].start(); ;-py h(  
hO.b?>3NL  
Fy E#@ R  
//等待子线程结束 xsRkO9x  
//int count = 0; Lm`-q(!7w  
//是否结束while循环 rBQ<5.  
boolean breakWhile = false; U@yhFj_y  
~%h )G#N  
|?^qsnB  
while(!bStop) Ieq_XF]U  
{ :^{KY(3  
write_nPos(); '
bM=  
Utility.sleep(500); aLm~.@Q  
breakWhile = true; kBC$dW-  
lv!
j  
T>(X`(  
for(int i=0;i<nStartPos.length;i++) &)t
v
4L&  
{ ,GVX1B?  
if(!fileSplitterFetch.bDownOver) Y0lLO0'  
{
4V,p\$;  
breakWhile = false; }qp)VF  
break; H6K8.  
} 6g#yzex  
} hV,T889'  
if(breakWhile) 'JdK0w#  
break; rWNe&gFM  
L#a!fd  
)O+Zbn  
//count++; R8lja%+0$  
//if(count>4) ?d?.&nt  
// siteStop(); GQYn |vm  
} ]5a3
e+  
/2=9i84  
PDS( /x&  
System.err.println("文件下载结束！"); 7@gH{p1  
} QwG_-  
catch(Exception e){e.printStackTrace ();} ZEDvY=@a   
} q+8de_"]  
#Pd__NV"\  
*74/I>i  
//获得文件长度 19O   
public long getFileSize() -U$;\1--  
{ hTEb?1CXU  
int nFileLength = -1; [6g$;SicT  
try{ }8}`A\dgV  
URL url = new URL(siteInfoBean.getSSiteURL()); J^#g?RHN>m  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \DE, ,  
httpConnection.setRequestProperty("User-Agent","NetFox"); C"5P7F{  
;?iu@h  
@ls/3`E/5E  
int responseCode=httpConnection.getResponseCode(); fATVAv  
if(responseCode>=400) nJv=kk1|o  
{ T<Y*();Zo  
processErrorCode(responseCode); 2<8l&2}7]  
return -2; //-2 represent access is error s1[.L~;J  
} ~e,l2 <  
~cO
iv  
vdUKIP =|_  
String sHeader; `IBNBJy
 
5cA:;{z];g  
v]Pyz<+  
for(int i=1;;i++) R%2.
N!8v  
{ 58HAl_8W  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ,']CqhL6=R  
//Utility.log(in.readLine()); NA0Z~Ug>  
sHeader=httpConnection.getHeaderFieldKey(i); DEkv,e  
if(sHeader!=null) havmhS)O  
{ G{X7;j e  
if(sHeader.equals("Content-Length")) C]JK'K<7-  
{ Zz:%KUl3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); FhBV.,bU,m  
break; y?r`[{L(lA  
} M/[
_~  
} ;m.6 ~A  
else eTgtt-;VR  
break; Ug0c0z!b  
} ,{(XT7hr  
} {*8G<&
 
catch(IOException e){e.printStackTrace ();} =6\^F i  
catch(Exception e){e.printStackTrace ();} rZB='(?  
x.pg3mVd>  

J1gnR  
Utility.log(nFileLength); $A,YQH+  
iE;F=Rb  
^a /q6{  
return nFileLength; rzie_)a Y%  
} 2)$-L'YS  
jFKp~`/#  
(#85<|z  
//保存下载信息（文件指针位置） 6Xo"?f  
private void write_nPos() 1K|F;p  
{ x{ `{j'  
try{ 3]}RjOTU  
output = new DataOutputStream(new FileOutputStream(tmpFile)); M?('VOy)  
output.writeInt(nStartPos.length); .C+(E@eyA  
for(int i=0;i<nStartPos.length;i++) P =Q+VIP&  
{ RiQg]3oY  
// output.writeLong(nPos); Jo;&~/V   
output.writeLong(fileSplitterFetch.nStartPos); N5K2Hv<"  
output.writeLong(fileSplitterFetch.nEndPos); K3=0D!Dq  
} {!?M!/d  
output.close(); F3o"ETle  
} 0cfGI%  
catch(IOException e){e.printStackTrace ();} @U?&1.\  
catch(Exception e){e.printStackTrace ();} %52x:qGa  
} Cq<Lj  
&'Nzw2  
T]/>c  
//读取保存的下载信息（文件指针位置） #k &#d9}  
private void read_nPos() :nl,Ac  
{ sEfT#$ a^8  
try{ Zi\ex\ )5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >y#qn9rV1  
int nCount = input.readInt(); pih 0ME}z  
nStartPos = new long[nCount]; r.Z g<T  
nEndPos = new long[nCount]; :?ZrD,D  
for(int i=0;i<nStartPos.length;i++) I!kR:Z  
{ H13\8Te{  
nStartPos = input.readLong(); ]D,_<Kk  
nEndPos = input.readLong(); <0~1  
} [x=(:soEqC  
input.close(); LN$T.r+  
} xf7YIhL^*  
catch(IOException e){e.printStackTrace ();} tV pXA'"!x  
catch(Exception e){e.printStackTrace ();} X+u1p?  
} %`]!atH  
Y+g(aak+.  
WLVkrTvX  
private void processErrorCode(int nErrorCode) 8a8D0}'  
{ Ie _{P&J  
System.err.println("Error Code : " + nErrorCode); rhaq!s38:  
} P&[&Dj  
)ryPK"V  
C}jrx^u>  
//停止文件下载 'TqF}a7  
public void siteStop() wm?%&V/#  
{ Xj30bt  
bStop = true; Y+$]N:\F\  
for(int i=0;i<nStartPos.length;i++) -jrA
k  
fileSplitterFetch.splitterStop(); 5efN5Kt  
Tw*p^rU  
*$;Zk!sEF  
} a
^juZ  
} {(Mmv[y  
//负责部分文件的抓取 `Z{s,!z  
**FileSplitterFetch.java z_KCG2=5  
*/ DMp@B]>  
package NetFox; 3'A0{(b  
rp1+K4]P  
>XiT[Ru
 
import java.io.*; 2w+4
B4  
import java.net.*; s?9Y3]&+&M  
#k>A,  
Nq9M$Nt]  
public class FileSplitterFetch extends Thread { 6r@>n_6LY  
ij3W8i9'  
^liW*F"UY  
String sURL; //File URL L+@X]OW8  
long nStartPos; //File Snippet Start Position 3q@JhB  
long nEndPos; //File Snippet End Position (ToD u@p  
int nThreadID; //Thread's ID lS p"(&  
boolean bDownOver = false; //Downing is over w0H#M)c  
boolean bStop = false; //Stop identical :1bDkoK  
FileAccessI fileAccessI = null; //File Access interface (@^ySiU  
{;u+?uY  
(w(k*b/  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException fsnZHL}=n  
{ J 48$l(l3  
this.sURL = sURL;  [Ne'2z  
this.nStartPos = nStart; 9Nv?j=*$  
this.nEndPos = nEnd;
X$P(8'[9A  
nThreadID = id; [[N${C  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~mK+Q%G5  
} Gp)J[8j  
K:AP 0Te  
Nx*1m BC  
public void run() ;qWSfCt/^  
{ "Vo
ufXM:  
while(nStartPos < nEndPos && !bStop) k w   
{ OkT@ _U  
]Z85
%q^`  
_]D 6m2R  
try{ ! jDopE0L  
URL url = new URL(sURL); 0sme0"Sl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9pS:#hg  
httpConnection.setRequestProperty("User-Agent","NetFox"); i-@V  
String sProperty = "bytes="+nStartPos+"-"; R@_3?Z!W=  
httpConnection.setRequestProperty("RANGE",sProperty); ^f"|<r  
Utility.log(sProperty); kG}F/GN?  
`2x.-  
0mmHN`<  
InputStream input = httpConnection.getInputStream(); gnxD'1_  
//logResponseHead(httpConnection); r[GH#vF;7  
 _X=6M gU  
zA3r&stN+  
byte[] b = new byte[1024]; IQ-l%x[fue  
int nRead; kFyp;=d:K  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Lg#(?tMp,'  
{ {7%HK2='  
nStartPos += fileAccessI.write(b,0,nRead); >@4AxV\  
//if(nThreadID == 1) 3kF+wifsz  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Cp>y<C"  
} CW/L(RQ  
A9"!=/~  
=iDd{$  
Utility.log("Thread " + nThreadID + " is over!"); cc}#-HKR[  
bDownOver = true; 9zCuVUcd$.  
//nPos = fileAccessI.write (b,0,nRead); 1Qz@  
} mV4gw'.;7  
catch(Exception e){e.printStackTrace ();}  P7/Xh3  
} T:|p[Xbo  
} E:PPb9Kd  
OP-{76vE&b  
g:G5'pZf  
//打印回应的头信息 +bJ~S:[  
public void logResponseHead(HttpURLConnection con) #,XZ@u+  
{ a{rUk%x  
for(int i=1;;i++) J}#2Wy^{  
{ W5:fY>7  
String header=con.getHeaderFieldKey(i); ,7k1n{C)  
if(header!=null) }?c%L8\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); =]pEvj9o  
Utility.log(header+" : "+con.getHeaderField(header)); ZZCm438  
else R1<$VR  
break; ^~@3X[No  
} ;<GxonIV  
} h5-yhG  
YmjA
!n  
Eelv i5  
public void splitterStop() @>J(1{m=Gy  
{ RQ^ \|+_  
bStop = true; W@'*G*f  
} b^ [ z'  
mh SknyqT  
 ?<8c  
} \n^[!e"`  
pFwJ:  
u!F\`Gfm_  
/* KHJ wCv  
**FileAccess.java C=cn.CX  
*//文件访问(定位，写) ]?oJxW.  
package NetFox; e-\/1N84  
import java.io.*; 3MKu!  
*n[BBz  
Z'}%Mkm`i}  
public class FileAccessI implements Serializable{ Q1|zX@,  
;#0$iE  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |k%1mE(+=s  
RandomAccessFile oSavedFile; 5ddfdIp  
long nPos; Ld/6{w4ir  
imAOYEH7}  
&}pF6eIar  
public FileAccessI() throws IOException 0G33hIOS  
{ Cx.##n0  
this("",0); ^=1u2YdVw  
} -o!bO9vC  
U0{)goN.  
l+hOD{F4pS  
public FileAccessI(String sName,long nPos) throws IOException Em5,Zr_  
{ ]+B.=mO_  
oSavedFile = new RandomAccessFile(sName,"rw"); ^W@%(,xb  
this.nPos = nPos; (~E-=+R[$&  
oSavedFile.seek(nPos); z5Tsu1c  
} t+]1D@hv  
H=g%>W%3  
`<|<1,  
public synchronized int write(byte[] b,int nStart,int nLen) |>m'szca4  
{ 8c_X`0jy  
int n = -1; i?uX'apk  
try{ B I3fk  
oSavedFile.write(b,nStart,nLen); @7.7+blS"H  
n = nLen; r3-<~k-  
} PB5h5eX  
catch(IOException e) .]JIo&>5  
{ T{"Ur:p  
e.printStackTrace (); n~}[/ly  
} k)X\z@I'  
$N;J)  
d%epM5  
return n; YPNW%N!$|  
} -/0\_zq7  
Q4a7g$^  
e#mqerpJ  
} 2k^rZ^^"  
}Q]-Y :  
MuP>#Vk  
/* 3]9Rmx  
**SiteInfoBean.java ,9_O4O%  
*/ wAX;)PLg  
package NetFox; dGkw%3[  
8e
,F{>N  
N mxh zjJ  
public class SiteInfoBean { lcjOBu  
4>vO9q  
j6XHH&ZEb  
private String sSiteURL; //Site's URL m.1-[2{8~  
private String sFilePath; //Saved File's Path J:&.[  
private String sFileName; //Saved File's Name CYwV]lq:s  
private int nSplitter; //Count of Splited Downloading File +'MO
$&6  
Tcc83_Iq  
D_~;!^  
public SiteInfoBean() ]vn*eqd  
{//nSplitter的缺省值为5 SE6(3f$  
//default value of nSplitter is 5 1TR+p? "  
this("","","",5); |B*B>P
#  
} BmccSC;o4  
: xg
go  
x|dP-E41\  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) qBh@^GxY),  
{ oSkQ/5hg.  
sSiteURL= sURL; bR~(Ry`  
sFilePath = sPath; _;Xlw{FN^  
sFileName = sName; )z18:C3  
this.nSplitter = nSpiltter; @U1|?~M%s  
gW--[  
>wt.)c?5  
} kD%MFT4  
C7*YZe  
^"54Q^SH  
public String getSSiteURL() |uw48*t  
{ dh [kx  
return sSiteURL; l5&5VC)  
} fR'!p: ~  
bn8maYUZ  
|)
Dm.)/0)  
public void setSSiteURL(String value) !t"/w6X1I  
{ "c]9Q%  
sSiteURL = value; {k-_+#W"  
} <#nU 06 fN  
b$fmU"%&|  
O2pE"8=4Q  
public String getSFilePath() fKqr$59>  
{ I *sT*;U  
return sFilePath; ecJjE 56P  
} 1hgIR^;[b  
'/9j"mIA9$  
U:n~S  
public void setSFilePath(String value) .FgeAxflP  
{ FK~wr;[  
sFilePath = value; :.]EM*p?GV  
} b+J|yM<`  
z _\L@b  
R+(f~
j'  
public String getSFileName() 3ej237~F,L  
{ ]GY8f3~|{  
return sFileName; ~/-SKGzo-  
} ;nW;M 4{  
R3lZ|rxv:  
JQ0Z%;"  
public void setSFileName(String value) LTo!DUi
`  
{ stUv!   
sFileName = value; hLgX0QV  
} m?B=?;B9#  
Fs $FR-x  
:.XlAQR~b  
public int getNSplitter()  ~,&8)1  
{ o4EY2  
return nSplitter; S|k@D2k=  
} 50-7L,  
tugIOA  
-
bOtF%  
public void setNSplitter(int nCount) C
kNR{?S  
{ yx-"&K=`  
nSplitter = nCount; mHju$d  
} Is3Y>o
X  
} cyB+(jLHDs  
XIbxi  
85Yi2+8f4  
/* '[F`!X  
**Utility.java hp2E! Cma  
*/ bF_0',W
 
package NetFox; $poIWJMc  
*qSvSY*  
zx=eqN@!@  
public class Utility { F)Q[ cai  
!]g[u3O  
U+B"$yBR  
public Utility() !wpK +.D  
{ yLf
yLyO L  
E Zf|>^N  
9D=X3{be#  
} /Z
abY  
|g^YD;9s.  
//线程睡眠 *kK +Nvt8s  
public static void sleep(int nSecond) l9eTghLi  
{ UsU
Ri  
try{ 9(S=0<  
Thread.sleep(nSecond); ';Nc;9  
} H@wjZ;R  
catch(Exception e) yy8BkG(  
{ t855|  
e.printStackTrace (); gsM$VaF(  
} T$2A2gb`  
} y< dBF[  
x  zF  
//日志 YB4 ZI  
public static void log(String sMsg) 1z&"V}y  
{ YQ?hAAJ  
System.err.println(sMsg); 2(3Q#3V  
} YB7A5  
f~P YK  
Khi6z&B  
public static void log(int sMsg) P
}gtJ;  
{ vjm? X  
System.err.println(sMsg); `^8mGR>OpI  
} a1I-d=]  
} ~Uv#)  
y4p"LD5%^  
!BkE-9v?w  
/* Ce<z[?u  
**TestMethod.java oowof
i(E  
*/ oi7k#^  
package NetFox; = E_i  
Y]`=cR`/"  
XZ@+aG_%q  
public class TestMethod { _(' @'r  
3Q62H+MC  
B\rY\  
public TestMethod() PZV>A!7C8n  
{ ///xx/weblogic60b2_win.exe V(ww F  
try{ t-C|x)J+  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); iH-,l  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 2RNee@!JJP  
SiteFileFetch fileFetch = new SiteFileFetch(bean); L7rr/D  
fileFetch.start(); 5TuwXz1v  
} 6q>iPK Jt  
catch(Exception e){e.printStackTrace ();} Wq}6RdY$ZA  
A#I&&qZ  
^C^I  
} |/l] ]+  
By7lSbj  
p.(+L^-=  
public static void main(String[] args) 0H +nVR  
{ Rh"O$K~  
new TestMethod(); %{r3"Q=;W  
} DUu:et&c1  
} |-{ Hy(9  
点击下载更多相关资料