http断点续传简单实现（java)

/* QWw"K$l  
**SiteFileFetch.java vO]J]][  
*/ :9`qogF>  
package NetFox; 4`s)ue  
import java.io.*; `y2ljIWJ  
import java.net.*; -bA!P
eI  
3w6&&R9  
X'@'/[?  
public class SiteFileFetch extends Thread { RJx{e
ck%  
zka?cOmYF[  
^sV|ck  
SiteInfoBean siteInfoBean = null; //文件信息Bean .Vmtx  
long[] nStartPos; //开始位置 +8f>^*:u
 
long[] nEndPos; //结束位置 ~T02._E  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +`| mJa  
long nFileLength; //文件长度 <7^Kt7k  
boolean bFirst = true; //是否第一次取文件 -D#5o,]3  
boolean bStop = false; //停止标志 T%kKVr  
File tmpFile; //文件下载的临时信息 ")ED)&e  
DataOutputStream output; //输出到文件的输出流 9`BEi(z  
&\k?xN  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） B9*Sfw%  
public SiteFileFetch(SiteInfoBean bean) throws IOException &:No}6  
{ t!{x<9  
siteInfoBean = bean; l<xFnj  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); +*C^:^jA  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >$uUuiyL4  
if(tmpFile.exists ()) e\r7BW\Y  
{ pDOM:lGya  
bFirst = false; oIb) Rq!m  
read_nPos(); Y 9i][  
} 0wFh%/:  
else -L8YJ8J6  
{ D#jX6  
nStartPos = new long[bean.getNSplitter()]; ?L\z}0#  
nEndPos = new long[bean.getNSplitter()]; @Dj:4  
} c4 5?St  
4UD' %}>y  
<Y>3  
W`x)=y]Z  
} RM,'o[%  
SKR;wu  
bnr|Y!T}Bi  
public void run()  eu9w|g  
{ HN68!v}C|  
//获得文件长度 :Fw?{0  
//分割文件 f=m/ -mAA  
//实例FileSplitterFetch u!Bk,}CE`  
//启动FileSplitterFetch线程 {y6C0A*  
//等待子线程返回 EwQae(PpA  
try{ h<Wg
3o  
if(bFirst) ,QvYTJ{  
{ F7T
E|LZ  
nFileLength = getFileSize(); TatMf;?h&  
if(nFileLength == -1) KO&:06V{  
{ l.oBcg[  
System.err.println("File Length is not known!"); G9Qe121m  
} Pm^lr!3p  
else if(nFileLength == -2) nY0sb8lZJ  
{ e+@xsn3  
System.err.println("File is not access!"); {ma;G[!  
} lKWr=k~  
else lzDdD3Ouc  
{ 5B*qbM  
for(int i=0;i<nStartPos.length;i++) s;1e0n  
{ tD-gc''H  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); )gXTRkmw  
} 4AHL3@x  
for(int i=0;i<nEndPos.length-1;i++) Hku=pr3Gn  
{ ^ ulps**e  
nEndPos = nStartPos[i+1]; w$>3pQ8
d  
} wmYv
D<  
nEndPos[nEndPos.length-1] = nFileLength; 1[DS'S  
} "2;N2=~7  
} Rp/-Pv   
U$'y_}V  
l>7r2;  
//启动子线程 2xTT)9Tq*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; TyOH`5D  
for(int i=0;i<nStartPos.length;i++) \hbiU]  
{ H/J<Pd$p  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
YqU/\f+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), wiE]z  
nStartPos,nEndPos,i); lIh[|]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T"!EK&  
fileSplitterFetch.start(); l!I
Gc:  
} ``9 GY  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^,V[nfQR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <TxC!{<  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Y=Hz;Ni  
nEndPos = " + nFileLength); J#7y< s  
// fileSplitterFetch[nPos.length-1].start(); \ e,?rH  
5@P-g  
]0/p 7N14  
//等待子线程结束 ]MAT2$"le  
//int count = 0; A*'V+(  
//是否结束while循环 nbxR"UH  
boolean breakWhile = false; B*,?C]0{  
c3k|G<C2  
NHkL24ve  
while(!bStop) ]US[5)EL-  
{ %;O}FyP  
write_nPos(); / L~u02?  
Utility.sleep(500); aws"3O% uW  
breakWhile = true; 8Rxc&`_X  

#J$qa Ul  
M!{'ED  
for(int i=0;i<nStartPos.length;i++) >5Lexj  
{ SI*^f\lu  
if(!fileSplitterFetch.bDownOver) Uix{"  
{ Jps .;yjk  
breakWhile = false; %j{.0H  
break; .Z%G@X*  
} \##`pa(8  
} %EI<@Ps8c  
if(breakWhile) sR*Nq5F#9  
break; Ze ? g  
ax@H"d&  
7co`Zw4}g  
//count++; d^84jf.U  
//if(count>4) OD+5q(!"a  
// siteStop(); P(h5=0`*PR  
} 2p:r`THvS5  
;V.vfar  
W9R`A  
System.err.println("文件下载结束！"); 8A{6j  
} 7X'y>\^w^>  
catch(Exception e){e.printStackTrace ();} _Bk U+=|J  
} _;e\:7<m  
D,rZ0?R  
}<[Db}?9  
//获得文件长度 +?d}7zh  
public long getFileSize() `6Hf&u<  
{ 97!5Q~I  
int nFileLength = -1; TzM=LvA  
try{ fk3kbdI  
URL url = new URL(siteInfoBean.getSSiteURL()); t(?<#KUB-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (5`T+pAsV  
httpConnection.setRequestProperty("User-Agent","NetFox"); $a.u05  

"mZ.V  
@{}rG8  
int responseCode=httpConnection.getResponseCode(); S,vu]?-8  
if(responseCode>=400) {XnPx?V  
{
p`>d7S>"  
processErrorCode(responseCode); ;^-:b(E  
return -2; //-2 represent access is error GGE[{Gb9  
} ;$!I&<)  
=nhzMU9c\y  
Tbh'_F6  
String sHeader; jA`a/vWu  
+hH}h?K  
V}9;eJRvw  
for(int i=1;;i++) ,sDr9h/'C3  
{ A1_ J sS  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); uec|S\~M  
//Utility.log(in.readLine()); uva\0q  
sHeader=httpConnection.getHeaderFieldKey(i); frH)_YJ%  
if(sHeader!=null) -g~~]K%  
{ (cs~@  
if(sHeader.equals("Content-Length")) Z.Pi0c+  
{ 3j
*'HST  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); A3s57.Z]|  
break; gX*K&*q   
} abW
l ut  
} GZ3/S|SMP  
else Q]\j>>  
break; #&siHHs \  
} ZvH{wt   
} /DU*M,  
catch(IOException e){e.printStackTrace ();} ;|30QUYh  
catch(Exception e){e.printStackTrace ();} r~oSP^e'  
&;v!oe   
KXe ka  
Utility.log(nFileLength); B||c(ue  
e@j8T gI)  
F]5\YYXO  
return nFileLength; %dmfBf Ev  
} H#+xKYrp  
|s|/]aD}o  
[g|Hj)(  
//保存下载信息（文件指针位置） },PBqWe  
private void write_nPos() {!=2<-Aq  
{ G(\Ckf:  
try{ :qnokrGzB  
output = new DataOutputStream(new FileOutputStream(tmpFile)); NI\H \#bJ  
output.writeInt(nStartPos.length); xOIg|2^8  
for(int i=0;i<nStartPos.length;i++) A&l7d0Z^j5  
{ _?b;0{93u  
// output.writeLong(nPos); $L&BT 0  
output.writeLong(fileSplitterFetch.nStartPos); mP!N<K  
output.writeLong(fileSplitterFetch.nEndPos); 4oJ$dN  
}
qGa<@
b  
output.close(); -+P7:4/  
} .Cr1,Po  
catch(IOException e){e.printStackTrace ();} ;*QN9T=0  
catch(Exception e){e.printStackTrace ();} N84qcc  
} %#9P?COs&W  
+*a7GttU  
)E`+BH  
//读取保存的下载信息（文件指针位置） o)!m$Q~v  
private void read_nPos() ^&m?qKN8  
{ \`gE
u{  
try{ q{@P+2<wF  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6ZksqdP8  
int nCount = input.readInt(); ;eh/_hPM  
nStartPos = new long[nCount]; hVZo"XUb  
nEndPos = new long[nCount]; 0n5!B..m}  
for(int i=0;i<nStartPos.length;i++) `[@VxGy_  
{ fq(5Lfe}  
nStartPos = input.readLong(); GZ"/k<~0  
nEndPos = input.readLong(); 9K$]h2  
} ,Hh*3rR^  
input.close(); _n_sfT6)B  
} I>Y{>S  
catch(IOException e){e.printStackTrace ();} "Q?_ EE
n  
catch(Exception e){e.printStackTrace ();} m&cvU>lC  
} $WClpvVj  
<Wf0QO,  
eP?~-#  
private void processErrorCode(int nErrorCode) O+vcs4  
{ *|poxT G  
System.err.println("Error Code : " + nErrorCode); -3]|[  
} 6Pijvx^0  
m9Il\PoTq  
mR,O0O}&  
//停止文件下载 B~rU1Y)  
public void siteStop() N"~ qoJO  
{ OA5f}+  
bStop = true; UAKu_RO6S  
for(int i=0;i<nStartPos.length;i++) ^(g_.>  
fileSplitterFetch.splitterStop(); LUG9 #.  
uAT/6@  
^Rk^XQCh  
} 8? F 2jv  
} GVZTDrC  
//负责部分文件的抓取 Tplg2p%k  
**FileSplitterFetch.java ?cJA^W  
*/ M#T#:wf~  
package NetFox; D@*|24y  
T,Fm"U6[(  
n5\}KZh  
import java.io.*; zg)|rm  
import java.net.*; _1\poAy  
`xGT_0&ck  
o Fi) d[`  
public class FileSplitterFetch extends Thread { ;tXY =  
c~37+^B:  
]
6q*)q:`  
String sURL; //File URL d96fjj~  
long nStartPos; //File Snippet Start Position IG&B2*  
long nEndPos; //File Snippet End Position RB *P
0  
int nThreadID; //Thread's ID A`g.[7  
boolean bDownOver = false; //Downing is over m'c#uU  
boolean bStop = false; //Stop identical f:&)"  
FileAccessI fileAccessI = null; //File Access interface 8,H~4Ce3  
Gg}t-_M  
Zq^^|[)bA  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1S
&0  
{ ePi 
Z  
this.sURL = sURL; OFp#<o,p  
this.nStartPos = nStart; PQi }Evxa  
this.nEndPos = nEnd; j+ I*Xw  
nThreadID = id; HMhLTl{;  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 y%JF8R;n  
} i"vDRrDe  
JLml#Pu4  
fs7~NY
 
public void run()
DVbYShB  
{ k~& o  
while(nStartPos < nEndPos && !bStop) KoFv0~8Q  
{ ";o~&8?)  
7WXiG0
 
=#jTo|~u4o  
try{ b#

e]1Q  
URL url = new URL(sURL); p0   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @kS|Jz$iY  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7bHE!#L`0  
String sProperty = "bytes="+nStartPos+"-"; GsI[N%  
httpConnection.setRequestProperty("RANGE",sProperty); \G]K,TG  
Utility.log(sProperty); S3nB:$_-;  
A(PE  
GpScc'a7  
InputStream input = httpConnection.getInputStream(); $tEdBnf^ca  
//logResponseHead(httpConnection); *13g<#$  
F_K  
{ 576+:*  
byte[] b = new byte[1024]; \m@]G3=]  
int nRead; $3lt{ %  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :vw0r`  
{ _xa}B,H  
nStartPos += fileAccessI.write(b,0,nRead); =CWc`  
//if(nThreadID == 1) XC :;Rq'j  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K3j_C`Se  
} 7sCR
!0  
?0? x+  
7k.d|<mRv  
Utility.log("Thread " + nThreadID + " is over!"); `^?}s-H+  
bDownOver = true; )r-T=  
//nPos = fileAccessI.write (b,0,nRead); ~GAlNIv]  
} 9yO{JgKA  
catch(Exception e){e.printStackTrace ();} ?T tQZ  
} Iq^~  
} wgC??Be;ut  
#(m`2Z`H  
Z|V"8jE  
//打印回应的头信息 j0ci~6&b3_  
public void logResponseHead(HttpURLConnection con) NEjPU#@c  
{ Xw&QrTDS`  
for(int i=1;;i++) +s#S{b  
{ em f0sL  
String header=con.getHeaderFieldKey(i); EGp~Vo-  
if(header!=null) !l sy&6  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); p~,a=  
Utility.log(header+" : "+con.getHeaderField(header)); 67Af} >Q  
else }S'I DHla  
break; p.6$w:eV  
} 0IoXDx  
} :DS2zA  
]>]#zu$=c  
QO
1A976o  
public void splitterStop() T4%i`<i  
{ r[C3u[  
bStop = true; )R [@G.  
} '6Pu[^x  
=:t@;y  
+G3nn!gl4  
} Pn'QOVy  
DTX/3EN  
"1gk-  
/* 2?#y |/  
**FileAccess.java &0;{lS[N:L  
*//文件访问(定位，写) 
,kGw;8X  
package NetFox; N"q+UCRC  
import java.io.*; UUdu;3E=5  
$sd3h\P&R  
i_oro"%yL  
public class FileAccessI implements Serializable{ :IP;FrcMP  
$
S($97IU=  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ~pX(w!^  
RandomAccessFile oSavedFile; 1 $KLMW  
long nPos; 0-;DN:>  
Lz#$_Am'H  
e')&ODQ H  
public FileAccessI() throws IOException nN_94 ZqS<  
{ }`+^|1  
this("",0); Ee$"O6*!  
} 9TbS>o
 
:FKYYH\  
thlp
j*|  
public FileAccessI(String sName,long nPos) throws IOException teQaHe#  
{ .g(\B  
oSavedFile = new RandomAccessFile(sName,"rw"); Pq[0vZ_}dN  
this.nPos = nPos; NIWI6qCw  
oSavedFile.seek(nPos); ]ut-wqb{p  
} i5>J  
E7Gi6w~\  
%>I?'y^  
public synchronized int write(byte[] b,int nStart,int nLen) c'TiWZP~  
{ Y*5@|Q  
int n = -1; M&}oat*  
try{ _Vk,&'  
oSavedFile.write(b,nStart,nLen); }Uq
a8&  
n = nLen; N%n1>!X)!  
} #+k.b_LS  
catch(IOException e) &}L36|A:  
{ Eezlx9b  
e.printStackTrace (); $Z(
g=nS>  
} )\I? EU8  
Up!ZCZ$RC  
<x>k
3bD  
return n; 5m%baf2_  
} alb+R$s  
]"2 v7)e  
{'=Nb 5F  
} U4^p({\|-  

]U^d1&k  
\^;|S  
/* gn[$;*932z  
**SiteInfoBean.java  n_xa)  
*/ <De3mZb  
package NetFox; 3wa<,^kqy  
r:8]\RU  
]\os`At  
public class SiteInfoBean { :>er^\  
\0^rJ1*  
t7*H8  
private String sSiteURL; //Site's URL cV=_GE  
private String sFilePath; //Saved File's Path '7O{*=`oj  
private String sFileName; //Saved File's Name WV!kA_  
private int nSplitter; //Count of Splited Downloading File xj00eL  
die2<'\4%  

K+`-[v5\  
public SiteInfoBean() !rsqr32]  
{//nSplitter的缺省值为5 QE{;M  
//default value of nSplitter is 5 nX.sh  
this("","","",5); dx?njR  
} r3BDq  
~D`oP/6  
S'%cf7Z  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) t\|K"  
{ asmW W8lz  
sSiteURL= sURL; abJ@>7V  
sFilePath = sPath; qqom$H<  
sFileName = sName; utm+\/  
this.nSplitter = nSpiltter; .'NO~  
G &
rYz  
4f*Ua`E_  
} p$b=r+1f  
thm3JfQt  
1A/c/iC  
public String getSSiteURL() +{Vwz  
{ sKB-7  
return sSiteURL; amk42  
} ,TfI  
{,-5k.P[  
M:1F@\<  
public void setSSiteURL(String value) -RqAT1  
{ nGJIjo_I  
sSiteURL = value; :86luLFm  
} l"pz )$eE  
(h@yA8>n  
>y06s{[  
public String getSFilePath() @#ho(_
U8  
{ EBL,E:_)  
return sFilePath; Z564K7IV  
} Zxxy1Fl#.[  
D'sboOY  
Cp~3Jm3  
public void setSFilePath(String value) IIt^e#s&  
{ (.XDf3  
sFilePath = value; tm36Lw  
} !K^Z5A_;  
"/K&qj  
:Z]+Z_9p  
public String getSFileName() )zLS,/pk^  
{ U37?P7i's  
return sFileName; hC 4X Y  
} tU2toV  
8|-mzb&  
,,H$>r_;  
public void setSFileName(String value) I}W-5%  
{ KutgW#+40  
sFileName = value; s3
E~X  
} m)]fJ_  
Mb2 L32  
)}it,<  
public int getNSplitter() <QoE_z`76  
{ 7%"\DLA  
return nSplitter; uSQ>oi]  
} :mtw}H 'F8  
t>h i$NX{p  
=|JIY  
public void setNSplitter(int nCount) ]{6yS9_tuI  
{ Q}f}Jf3P  
nSplitter = nCount; N5an9r&z(1  
} (7jB_ p%  
} n\ ',F  
J)yy}[Fx  
lbuW*)  
/* =UKR<@QrK  
**Utility.java .gkPG'm[  
*/ AoOG[to7  
package NetFox; 674oL,  
z9kX`M+  
<%#y^_  
public class Utility { q~dg  
@G$<6CG\  
3;l>x/amk  
public Utility() .s*EV!SE  
{ $\@ 
V4  
,t&-`U]AX  
~md|k  
} ^F
Ma8;'o  
.rB;zA;4S)  
//线程睡眠 n ua8y(W  
public static void sleep(int nSecond) I~]mX;  
{ MbFe1U]B  
try{ #|_UA}Y  
Thread.sleep(nSecond); *_K-T#  
} GuY5 %wr  
catch(Exception e) <w2NJ~M^  
{ 6.7Kp  
e.printStackTrace (); |{LaZXU&  
} XM@i|AK M0  
} P$ dgO  
Z *
<x  
//日志 [ EID27P  
public static void log(String sMsg) H!>oLui  
{ .&}4  
System.err.println(sMsg); 95 .'t}  
} 3XlnI:w=  
MMr7,?,$  
hYv 6-5_  
public static void log(int sMsg) <J}9.k
 
{ |QTqa~~B  
System.err.println(sMsg); iEgM~  
} -+_
aL4.  
} -Fc#  

4
kF .  
Yg,lJ!q  
/* n@,eZ!  
**TestMethod.java p{svXP K  
*/ qVe6RpS  
package NetFox; 4NR5?s  
5a|m}2IX  
8lGgp&ey  
public class TestMethod { (Dh;=xG  
S!!\!w>N  
2/4x]i H*  
public TestMethod() .'mC3E+$  
{ ///xx/weblogic60b2_win.exe F20-!b  
try{ .-~%w  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 3v>,c>b([  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _7"W\gn:9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ,zw=&)W1  
fileFetch.start();  mFoK76  
} 9x^ /kAB  
catch(Exception e){e.printStackTrace ();} m:Cx~  
'L59\y8H  
=}GyI_br;8  
} ];~[Olc  
(0m$W<  
2LH;d`H[0  
public static void main(String[] args) e.ym7L]$O  
{ Wy>\KrA1  
new TestMethod(); E/P53CD  
} P(nHXVSUE  
} PjZvLK@a9)  
点击下载更多相关资料