http断点续传简单实现（java)

/* nXxnyom,  
**SiteFileFetch.java 5=4-IO6W[]  
*/ Vr&v:8:wb  
package NetFox; g|!=@9[dv  
import java.io.*; Z@Qf0 c  
import java.net.*; 1;>RK  
BMhuM~?(  
H"2,Q T  
public class SiteFileFetch extends Thread { q93V'[)F  
mj y+_  
gJzS,g1]  
SiteInfoBean siteInfoBean = null; //文件信息Bean Z \-  
long[] nStartPos; //开始位置 er!+QD,EM  
long[] nEndPos; //结束位置 OQT i$2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 {Z[kvXf"mZ  
long nFileLength; //文件长度 VAa;XVmB  
boolean bFirst = true; //是否第一次取文件 TR{dNO!q  
boolean bStop = false; //停止标志 \z2d=
E  
File tmpFile; //文件下载的临时信息 B_.>Q8t
K;  
DataOutputStream output; //输出到文件的输出流 IRI<no  
r8L'C  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Zo,]Dx  
public SiteFileFetch(SiteInfoBean bean) throws IOException q?&JS  
{ P$
G|o|h  
siteInfoBean = bean; .q$/#hN:e  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); +T7FG_  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); HYg7B  
if(tmpFile.exists ()) ?Ye%k  
{ ]JI A\|b6  
bFirst = false; ;!>>C0s"  
read_nPos(); j;*= ^s  
} [dXRord  
else 'zTa]y]a  
{ e?-LB  
nStartPos = new long[bean.getNSplitter()]; VH.}}RS%  
nEndPos = new long[bean.getNSplitter()]; ve= nh]N  
} R~BW=Dz,e  
.ZH5^Sv$vp  
`3F/7$q_  
\V.U8asfI  
} ,u>K##X\  
E}=F   
;4]l P  
public void run() z[_Gg8e  
{ 2O9OEZdKB  
//获得文件长度 knZ<V%/e  
//分割文件 QgX[?2  
//实例FileSplitterFetch /?QBMI  
//启动FileSplitterFetch线程 .w]S!=h  
//等待子线程返回 w9a6F  
try{ Jz\'%O'  
if(bFirst) <3Hu(Jx<O  
{ k$} 6Qd  
nFileLength = getFileSize(); J)Td'iT(  
if(nFileLength == -1) ~# |p=Y  
{  6@ )bZ|  
System.err.println("File Length is not known!"); rk(0w|zR+  
} u8@>ThPD  
else if(nFileLength == -2) cj/FqU"  
{ 5=Y\d,SS"  
System.err.println("File is not access!"); h9J  
} ;rH@>VrR  
else bwh.ekf8  
{ |4a#O8d  
for(int i=0;i<nStartPos.length;i++) yf6&'Y{  
{ YEqWTB|w  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); (wIpq<%  
} %Gs!oD  
for(int i=0;i<nEndPos.length-1;i++) DavG=kvd  
{ hYNb9^  
nEndPos = nStartPos[i+1]; VN8ao0^d;d  
} vd<" G}  
nEndPos[nEndPos.length-1] = nFileLength; Y,@{1X`0@3  
} 07+Qai-]  
} %fz!'C_4  
$Mp#tH28  
^T|~L
<A3  
//启动子线程 ABp/uJI
)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; &6L{1  
for(int i=0;i<nStartPos.length;i++) L1k_AC1.M
 
{ b fsTeW+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?79ABm a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), FiqcM-Af4  
nStartPos,nEndPos,i); uIvE~<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); iB5Se  
fileSplitterFetch.start(); o3l_&?^  
} 6F3#Rxh  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (v8jVbg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); I%whM~M1+  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", xAD:Z"  
nEndPos = " + nFileLength); 70:a2m  
// fileSplitterFetch[nPos.length-1].start(); e? fFh,a  
K/jC>4/c/  
D[)g-_3f6<  
//等待子线程结束 6nRD:CH)X  
//int count = 0; *eytr#0B-  
//是否结束while循环 tq^H)  
boolean breakWhile = false; NQ!jkojD  
|}\et ecB  
n-{G19?  
while(!bStop) ^60BQ{ne  
{ M:qeqn+  
write_nPos(); </|I
gN$w`  
Utility.sleep(500); W9T,1h5x  
breakWhile = true; T'l >$6  
@twClk.s  
`|;R}"R;  
for(int i=0;i<nStartPos.length;i++) Z*QsDS  
{ CC>]Gc7  
if(!fileSplitterFetch.bDownOver) %uyRpG3,  
{ jyf[O -  
breakWhile = false; 'tp1|n/1  
break; :0j9  
} |jniI(  
} v*1UNXU\  
if(breakWhile) jnX9] PkJ  
break; QdL ;|3K9  
DGTSk9iK(  
Im1e/F]  
//count++; !h{qO&ZH=  
//if(count>4) 7%9Sz5z  
// siteStop(); G_g~-[O  
} Y0=qn'`.  
ao<@a{G  
!*ct3{m  
System.err.println("文件下载结束！"); \:-#,( .V  
} @|v4B[/  
catch(Exception e){e.printStackTrace ();} I3]-$  
} Nl,M9  
^EWkJW,Yc  
~q4KQ&.!  
//获得文件长度 9{@[l!]W  
public long getFileSize() #'fh'$5"  
{ k'E3{8<!  
int nFileLength = -1; z^$DXl@)h  
try{ 2jV.\
C k  
URL url = new URL(siteInfoBean.getSSiteURL()); KWbnSL8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \7rFfN3  
httpConnection.setRequestProperty("User-Agent","NetFox"); qPGpN0M`  
ggtGecKm  
Xptb4]  
int responseCode=httpConnection.getResponseCode(); kIhP 73M  
if(responseCode>=400) e\%+~GUTC=  
{ m/RX~,T*v&  
processErrorCode(responseCode); u+%Ca,6  
return -2; //-2 represent access is error B,@geJ  
} b9Jah  
8+Sa$R  
ms2y[b  
String sHeader; CZ"~N`  
P,U$ X+  
vaN}M)W/  
for(int i=1;;i++) 07 [%RG  
{ S`g:zb_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); F5la:0fb  
//Utility.log(in.readLine()); (?R;u>  
sHeader=httpConnection.getHeaderFieldKey(i); 4j^-n_T  
if(sHeader!=null) IX@g].)C  
{ ]5| o8.  
if(sHeader.equals("Content-Length")) 4g<F."  
{ vU,AOK[l{  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); eD5:0;X2  
break; p|fSPSz  
} &c!d}pU}  
} C><]
o  
else !kCMw%[  
break; {p3VHd#  
} Axp#8  
} {6H%4n  
catch(IOException e){e.printStackTrace ();} GVS-_KP\  
catch(Exception e){e.printStackTrace ();} T,N"8N{K"  
[O~'\Q  
h1O^~"x  
Utility.log(nFileLength); /IQl  
&%J+d"n(  
@;>i3?  
return nFileLength; [4qCW{x._  
} kkWqP20q  
4cZig\mE;  
kg@D?VqJP  
//保存下载信息（文件指针位置） P(iZGOKUs=  
private void write_nPos() rb
8c^u#r  
{ )gM3,gSS  
try{ @L?X}'0xI4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^Ej4^d  
output.writeInt(nStartPos.length); 2hB';Dv  
for(int i=0;i<nStartPos.length;i++) lIR0jgP@z  
{ :CH*~o  
// output.writeLong(nPos); [HEqMBX=;  
output.writeLong(fileSplitterFetch.nStartPos); %Xm3m0nsv{  
output.writeLong(fileSplitterFetch.nEndPos); 4a'O#;ho  
} O<}^`4d  
output.close(); /48W]a}JS  
} _PTo!aJL  
catch(IOException e){e.printStackTrace ();} +a'QHtg  
catch(Exception e){e.printStackTrace ();} Y# <38+Gd  
} a2:Tu  
xL.T}f~y2>  
In
1VW|4h  
//读取保存的下载信息（文件指针位置） Y-8qAF?SJ]  
private void read_nPos() iC U[X&  
{ XBJ9"G5  
try{ *~p~IX{  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); F[aow$",+}  
int nCount = input.readInt(); fX.V+.rj  
nStartPos = new long[nCount]; &p?Oo^  
nEndPos = new long[nCount]; s3G\L<~mB  
for(int i=0;i<nStartPos.length;i++) NW-l_]k  
{ 6k#H>zY,  
nStartPos = input.readLong(); .aRL'1xHl  
nEndPos = input.readLong(); +{%@kX<V_  
} Sr7+DCr  
input.close(); C=LXL1x2e  
} 1[k~*QS  
catch(IOException e){e.printStackTrace ();} C:tA|<b|  
catch(Exception e){e.printStackTrace ();} 2>{_O?UN  
} ":,HY)z  
wu*WA;FnA  
IBwquw+  
private void processErrorCode(int nErrorCode) 7f4R5
c  
{ (wJtEoB9^  
System.err.println("Error Code : " + nErrorCode); uO$ujbWZ  
} V/5hEoDt  
S"|sD|xOb  
Q*TxjE7K  
//停止文件下载 {Y5h*BD>  
public void siteStop() uo1G   
{ Tb-`0^y&X1  
bStop = true; =goZI67  
for(int i=0;i<nStartPos.length;i++) `92 D]^g  
fileSplitterFetch.splitterStop(); l3aG#4jj  
lY}mrb  
,2>:h"^  
} @LY 5]og  
} -X@;"0v  
//负责部分文件的抓取 SwQ.tK1p  
**FileSplitterFetch.java dE5DH~ldV  
*/ VmQ7M4j*  
package NetFox; h3;Ij'  
PF.sM(  
l,/q#)5[  
import java.io.*; aMTY{  
import java.net.*; 
^F*)Jq  
_lQ+J=J$.R  
+N[dYm  
public class FileSplitterFetch extends Thread { |
D^Q}uT  
Xi5kE'_  
hvBuQuk)  
String sURL; //File URL v\Y;)/!  
long nStartPos; //File Snippet Start Position !W:QLOe6F  
long nEndPos; //File Snippet End Position Coq0Kzhsab  
int nThreadID; //Thread's ID rO
Y^w9!  
boolean bDownOver = false; //Downing is over [[D}
vL8d  
boolean bStop = false; //Stop identical qn@Qd9Sf  
FileAccessI fileAccessI = null; //File Access interface ,|I\{J #C  
9szE^kHS9  
c7\bA7.  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException p!'
wOThO`  
{ mUy/lo'4  
this.sURL = sURL; "EpE!jh  
this.nStartPos = nStart; JXj`  
this.nEndPos = nEnd; z!Kadqns  
nThreadID = id; ~s^&*KaA  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7k6rhf7H  
} B4R,[WE"  
NtTLvO6  
w]yLdfi!  
public void run() n
2#uH  
{ aic6,>\!'  
while(nStartPos < nEndPos && !bStop) B_cn[?M  
{ $ O!f*l
G  
y8+?:=N.  
>\DXA)nc  
try{ V2/+SvB2  
URL url = new URL(sURL); (%0X\zvu/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); N#.IpY'7Ze  
httpConnection.setRequestProperty("User-Agent","NetFox"); n]Dq  
String sProperty = "bytes="+nStartPos+"-"; s*9tWSd  
httpConnection.setRequestProperty("RANGE",sProperty); A#1y
>k  
Utility.log(sProperty); 6\o.wq  
5!nZvv  
[RpFC4W  
InputStream input = httpConnection.getInputStream(); FeV=4tsy  
//logResponseHead(httpConnection); xC;$/u%'  
ZQBo|8*  
Kg](kP  
byte[] b = new byte[1024]; b!.# `.  
int nRead; /v!H{Zw=c  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) L0&!Qct  
{ g"Ii'JZ?  
nStartPos += fileAccessI.write(b,0,nRead); 3al5Vu2:  
//if(nThreadID == 1) 609=o+  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?tA-`\E  
} NZlJ_[\$C  
<K\F/`c  
[2\`Wh:%P  
Utility.log("Thread " + nThreadID + " is over!"); 73<iK]*c  
bDownOver = true; Y-{spTI  
//nPos = fileAccessI.write (b,0,nRead); l|up3A3)  
} pF!vW  
catch(Exception e){e.printStackTrace ();}
9=}/t9k  
} <1LuYEDq  
} /nmfp&@  
2mT+@G  
L%8"d6  
//打印回应的头信息 6?iP z?5  
public void logResponseHead(HttpURLConnection con) p
-6.:y  
{ VN".NEL  
for(int i=1;;i++) bG&qgbN>  
{ P4AdfHk  
String header=con.getHeaderFieldKey(i); a$|u!_)!h  
if(header!=null) V9bLm,DtT  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); VsMNi#?  
Utility.log(header+" : "+con.getHeaderField(header)); |V7a26h  
else nc{<v  
break; N|)V/no6  
} 3//v{ce1]  
} S\rfR N  
"O 'I  
Smux&e  
public void splitterStop() `->k7a0<b1  
{ gc:>HX);)  
bStop = true; M*HG4(n0  
} >dGYZfqD  
=w8 YZs8w  
CUG<v3\  
} &Os Ritj  
]>,|v,i =  
;Vy'y  
/* iau&k`b`  
**FileAccess.java c2f$:XiM  
*//文件访问(定位，写) E;Hjw0M'k  
package NetFox; /km3L7L%R  
import java.io.*; w6Q]?p+  
Oe!&Jma*>  
3"n8B6
 
public class FileAccessI implements Serializable{ F)w83[5_d  
SAJ=)h~  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 "U.=A7r  
RandomAccessFile oSavedFile;
~] 2R+  
long nPos; 6hq)yUvo4  
y|se^dn  
]l'ki8  
public FileAccessI() throws IOException zJ`(LnV  
{ s`YuH <8  
this("",0); dFFqs&cQ  
} ^'4uTbxP_!  
bYc qscW  
z;
fSd  
public FileAccessI(String sName,long nPos) throws IOException :bDA<B6bb  
{ ^aCYh[
=  
oSavedFile = new RandomAccessFile(sName,"rw"); vBx^zDe  
this.nPos = nPos; V1`|j  
oSavedFile.seek(nPos); O;BPd:<  
} L#Y;a 5b  
v!xrUyN~m  
UGt7iT<`8  
public synchronized int write(byte[] b,int nStart,int nLen) !e `=UZe1  
{ QO/7p]$_  
int n = -1; Nk4_!  
try{ |plo65  
oSavedFile.write(b,nStart,nLen); =[+&({  
n = nLen; R <\Yg3m8  
} iGk{8Da<  
catch(IOException e) Dys"|,F  
{ %ko 8P  
e.printStackTrace (); jt--w"|-r  
} HPKyAcS\  
MA#!<b('  
3+5\xRq  
return n; :q<%wLs  
} )`7+o9&  
@|Bp'`j%J  
zEfD{I  
} U&$]?3?  
K<JP9t6Qd  
ss8v4@C  
/* 6CRPdLTDf  
**SiteInfoBean.java ZMg9Qt  
*/ r.^X>?  
package NetFox; em!R9J.  
z.HNb$;  
%
esZ}U  
public class SiteInfoBean { K0=E4>z,`q  
"mDrJTWa  
6G$tYfX  
private String sSiteURL; //Site's URL f+Li'?  
private String sFilePath; //Saved File's Path Vzvw/17J  
private String sFileName; //Saved File's Name uN3J)@;_  
private int nSplitter; //Count of Splited Downloading File !BuJC$  
6XK`=ss?  
A!Ct,%   
public SiteInfoBean() 91d`LsP  
{//nSplitter的缺省值为5 c.A/{a  
//default value of nSplitter is 5 YPDsE&,J)  
this("","","",5); N:jiZ)  
} pbxcsA\  
|0R%!v(,  
DB'KIw  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) "d>g)rvOc  
{ {59VS Nl  
sSiteURL= sURL; <?7,`P:h[  
sFilePath = sPath; zRE8299%z  
sFileName = sName; lT!$\E$1   
this.nSplitter = nSpiltter; <O)X89dFM  
YkAWKC
Oni  
)r,R!8  
} 7+hF;  
FDs^S)B  
@mRrA#E#{  
public String getSSiteURL() 'Qq_Xn8  
{ cPaWJ+c  
return sSiteURL; nEcd+7(  
} a:^Gr%  
"mK i$FV  
qq7X",s  
public void setSSiteURL(String value) r
jQhU%zv  
{ bKJ7vXC05  
sSiteURL = value; Dzjt|U0ru9  
} zpr@!76  
{!eANm'  
4J 51i*`  
public String getSFilePath() Y{2d4VoW6  
{ >g"M.gW  
return sFilePath; <CKmMZ{  
} $gl<{{  
grxl{uIC8  
N|O]z  
public void setSFilePath(String value) eQaxZMU  
{ zvb}p  
sFilePath = value; ss
yd8LC#  
} i|]Va44  
hn\Q6f+  
-0VA!3l  
public String getSFileName() {+6D-rDw  
{ T'b/]&0Tio  
return sFileName; pz35trW  
} T<e7(=  
|*c\6 :  
uGUv~bE  
public void setSFileName(String value) ^g-t#O lD?  
{
Z-h7   
sFileName = value; y-\A@jJC5  
} sId(PT^  
?X#/1X%u:  
hUT^V(  
public int getNSplitter() -?YTQ@ W  
{ 6(J4IzZ  
return nSplitter; 2Jo~m_  
} pba8=Z  
'LbeL1ca  
%t`SSW7I  
public void setNSplitter(int nCount) ;w6fM  
{ T4~`e_  
nSplitter = nCount; 3 IWLBc  
} WfDX"rA  
} 
"rx^M*"  
"7yNKO;W  
6vgBqn[  
/* `/w\2n  
**Utility.java EY)Gi`lK  
*/ ) Kc%8hBv  
package NetFox; 2T@L{ql  
BU9J_rCIv  
Ki/'
Ic1  
public class Utility { a4T~\\,dZ>  
)>y k-  
e`Co,>W/  
public Utility() 1^L`)Up  
{ /BMtcCPG!  
^KkRF":  
/}w#Jk4pD  
} WDEe$k4.  
^Ue0mC7m  
//线程睡眠 WG
h. ;-  
public static void sleep(int nSecond) (S  k#x
 
{ 6X7s 4  
try{ ,M)k7t:  
Thread.sleep(nSecond); T~%H%O(F  
} Mny'9hsl  
catch(Exception e) jow7t\wk  
{ Q PFeBl  
e.printStackTrace (); iW|s|1mh3  
} JBR[; zM  
}  c6Lif)4  
?wd|G4.Vo  
//日志 e=t<H"&  
public static void log(String sMsg) v@8S5KJ  
{ ?fK^&6pI  
System.err.println(sMsg); 60GFVF]'2  
} #(%t*"IY;  
d/XlV]#2x\  
8p (!]^z  
public static void log(int sMsg) Bx(yu'g|a  
{ D@8jGcz62  
System.err.println(sMsg); YywEZ?X  
} 0Injyc*bMF  
} 5kcJ  
~~PgF"v  
1~%o}+#-  
/* )YuRjBcp,"  
**TestMethod.java
'#v71,  
*/ )ll?-FZ   
package NetFox; tbq|,"  
/7bw: h;  
4s9c#nVlu  
public class TestMethod { : *ERRSL)  
o2DtCU-A  
$`|5/,M%QN  
public TestMethod() RC
zV5g  
{ ///xx/weblogic60b2_win.exe
81Z4>F:  
try{ W1vCN31  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Bg-VCJI<  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,
Ij=b  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +%P t_  
fileFetch.start(); TWUUvj`.  
} |U#DUqw  
catch(Exception e){e.printStackTrace ();} l '/N3&5  
;Xqn-R  
qgtn5]A  
} kl" ]Nw'C  
L?!$EPr  
Q uB+vL  
public static void main(String[] args) Yv^p=-E  
{ KxY$PgcC  
new TestMethod(); UR}kB&t  
} u+i(";\  
} >9=:sSQu  
点击下载更多相关资料