http断点续传简单实现（java)

/* NE"jh_m-
 
**SiteFileFetch.java A2x;fgi  
*/ |)@N-f:E  
package NetFox; -PAF p3w\y  
import java.io.*; nj\_lL+  
import java.net.*; U '[?9/T  
1h"_[`L'  
#/j={*-  
public class SiteFileFetch extends Thread { Fu8 7fVi/\  
{4ptu~8  
C4$/?,K(  
SiteInfoBean siteInfoBean = null; //文件信息Bean ]2+g&ox4'  
long[] nStartPos; //开始位置 hbuZaxo<  
long[] nEndPos; //结束位置 dyQh:u -  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4Y tk!oS`  
long nFileLength; //文件长度 ~hURs;Sb  
boolean bFirst = true; //是否第一次取文件 ${U6=  
boolean bStop = false; //停止标志 oVZ4bRl   
File tmpFile; //文件下载的临时信息 u9![6$R  
DataOutputStream output; //输出到文件的输出流 Y~oT)wTU  
Rq7p29w  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） W81o"TR|pt  
public SiteFileFetch(SiteInfoBean bean) throws IOException j"<Y!Y3  
{ NMjnL&P`  
siteInfoBean = bean; 015Owi  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); g=A$<k
 
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); yBz>0I3  
if(tmpFile.exists ()) $<e +r$1  
{ J(d2:V{h  
bFirst = false; \iMyo  
read_nPos(); E!aq?`-'!  
} +Z?[M1g  
else q|q::q*  
{ [Hcaw   
nStartPos = new long[bean.getNSplitter()]; eX<K5K.B  
nEndPos = new long[bean.getNSplitter()]; wsg//Ec]  
} FU@uH U5fd  
Wp*sPZ  
R'EW7}&  
U($^E}I2(  
} L? ;/cO^  
$P?{O3:V  
o_yRn16  
public void run() xQz
#i-v  
{ "2h5m4  
//获得文件长度 A9BxwQU#  
//分割文件 ZBj6KqfST%  
//实例FileSplitterFetch `=!p$hg($  
//启动FileSplitterFetch线程 ez0\bym  
//等待子线程返回 >=!AL,:  
try{ ?;8M^a/  
if(bFirst) 6=>7M b$  
{ k.Zll,s  
nFileLength = getFileSize(); ?"@ET9  
if(nFileLength == -1) md6*c./Z  
{ 3%NE/lw1  
System.err.println("File Length is not known!"); K<,Y^3]6?  
} N&B>#:  
else if(nFileLength == -2) 5X;?I/9  
{ Dy
I2Ye  
System.err.println("File is not access!"); $DV-Ieb  
} fH!=Zb_{8  
else H!JWc'(<$  
{ EHWv3sR-  
for(int i=0;i<nStartPos.length;i++) p#b{xK  
{ -IvL+}K  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); $i&\\QNn  
} eH=c|m]!P  
for(int i=0;i<nEndPos.length-1;i++) \|!gPc%s  
{ S 1ibw\'  
nEndPos = nStartPos[i+1]; ,iOZ|  
} &5/JfNe3  
nEndPos[nEndPos.length-1] = nFileLength; wU0K3qZL
 
} Ak|b0l>^  
} &9h  
n49s3|#)G  
f)tc4iV  
//启动子线程 t/LgHb:)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 7sN0`7  
for(int i=0;i<nStartPos.length;i++) `Y\QUj  
{ 1OPfRDn.bk  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N K"%DU<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [Ye5Y?  
nStartPos,nEndPos,i); ~D!ESe*=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8XkIk7  
fileSplitterFetch.start(); Qy%xL9  
} sVD([`Nmc  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), j}RM.C\7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); akrCs&Kka5  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", hE5G!@1F  
nEndPos = " + nFileLength); 3dU#Ueu  
// fileSplitterFetch[nPos.length-1].start(); 5|m9:Hv[#  
J]]\&MtaO  
#]5)]LF1q  
//等待子线程结束 (lWKy9eTy`  
//int count = 0; 1?]J;9p  
//是否结束while循环 QZYM9a>  
boolean breakWhile = false; DD6'M U4  
A xR\ned  
&u4Ve8#  
while(!bStop) i\Q":4  
{ PE7t_iSV  
write_nPos(); >!G5]?taa
 
Utility.sleep(500); j~$)c)h"  
breakWhile = true; 2E([#Pzb  
p(7c33SyF  
x[a'(5PwY  
for(int i=0;i<nStartPos.length;i++) lzI/\%  
{ " xxXZGUp  
if(!fileSplitterFetch.bDownOver) k^yy$^=<  
{ tpz=}q  
breakWhile = false; ^X(_zinN"  
break; C0f[eA  
} TQ2i{e
 
} gTyW#verh$  
if(breakWhile) sK[Nti0  
break; (T;1q^j  
?bCTLt7k  
]N_140N~  
//count++; ?xf~!D  
//if(count>4) aH9L|BN*  
// siteStop(); )rS^F<C  
} 2PI #ie4  
B4 <_"0  
OT"lP(,  
System.err.println("文件下载结束！"); ~CJYQFt  
} R=QM;  
catch(Exception e){e.printStackTrace ();} H;X~<WN&AW  
} G)K9la<p  
!zl/0o  
@nW'(x(  
//获得文件长度 L7[X|zmy*x  
public long getFileSize() }cyq'mi  
{ r}Q@VS%%  
int nFileLength = -1; VN!^m]0  
try{ Q9nu"x %  
URL url = new URL(siteInfoBean.getSSiteURL()); J~:kuf21  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @D2`*C9  
httpConnection.setRequestProperty("User-Agent","NetFox"); -1#e^9Ve\  
yW'BrTw  
Wa@6VY  
int responseCode=httpConnection.getResponseCode(); $t%"Tr  
if(responseCode>=400) Z|f^nH#-C  
{ &AN%QhI  
processErrorCode(responseCode); l'P[5'.  
return -2; //-2 represent access is error c '/2F0y  
} b<48#Qy~l  
,\Z8*Jr3Q  
Lp~c  
String sHeader; baA HP"  
mn,=V[f  
9eksCxFg  
for(int i=1;;i++) 7Ljs4>%l9j  
{ 5,g$|,Shv  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); `<bCq\+`  
//Utility.log(in.readLine()); =]6_{#Z<  
sHeader=httpConnection.getHeaderFieldKey(i); D_]i/ F%  
if(sHeader!=null) '
[0 3L9  
{ %Tk}sfx  
if(sHeader.equals("Content-Length")) I*%&)Hj~  
{ ok8JnQC
 
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (}~ 1{C@  
break; t^dakL  
} &fh.w]\  
} K1CMLX]m  
else ^?JEyY  
break; \=TWYj_Ah  
} oo"JMD)  
} us(sZG  
catch(IOException e){e.printStackTrace ();} kemr@_  
catch(Exception e){e.printStackTrace ();} H7 o$O  
`=WzG"  
IiQWs1  
Utility.log(nFileLength); Yf%[6Y{  
9p!dQx  

5LnB]dW  
return nFileLength; Au%Wrk3j  
} m mw)C"  
t(Cq(.u`:  
!:`Ra  
//保存下载信息（文件指针位置） a'(lVZA;  
private void write_nPos() +/1P^U /  
{ gqKC4'G0  
try{ 1mkQ"E4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); zcbA)
  
output.writeInt(nStartPos.length); 9;'>\ImI  
for(int i=0;i<nStartPos.length;i++) V~tu<"%  
{ uT@8 _9  
// output.writeLong(nPos); xQcMQ{&;  
output.writeLong(fileSplitterFetch.nStartPos); b3jU~L$  
output.writeLong(fileSplitterFetch.nEndPos); }6b7a1p  
} ?3e!A9x  
output.close(); \Mh4X`<e  
} _,Io(QS  
catch(IOException e){e.printStackTrace ();} KG7X8AaK#  
catch(Exception e){e.printStackTrace ();} !'c6Hs  
} %t(, *;  
H znI R  
qugPs(uQ  
//读取保存的下载信息（文件指针位置） -bIpmp?  
private void read_nPos() oC;l5v<  
{ ^[SbV^DOL  
try{ gw*yIZ@3)  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =!Baz&#}  
int nCount = input.readInt(); gGceK^#  
nStartPos = new long[nCount]; 1yY'hb,0  
nEndPos = new long[nCount]; QB oZCLv  
for(int i=0;i<nStartPos.length;i++) d60Fi#3d  
{ a93d'ZE-X  
nStartPos = input.readLong(); 4%Z\G@0<'  
nEndPos = input.readLong(); P,+0   
} 2t~7eI%d  
input.close(); O=9VX  
} p>w~T#17  
catch(IOException e){e.printStackTrace ();} WL*W=(  
catch(Exception e){e.printStackTrace ();} cfQh  
} }r\SP3  
\3@2rW"5  
Z{|.xgsY  
private void processErrorCode(int nErrorCode) 1f bFNxo8M  
{ ~]D\&D9=?  
System.err.println("Error Code : " + nErrorCode); #RZJ1uL  
} Vtc)/OH  
*RqO3=  
q#':aXcv"  
//停止文件下载 LU 5 `!0m  
public void siteStop() hBs>2u|z9  
{ EZa{C}NQ$2  
bStop = true; QL|:(QM  
for(int i=0;i<nStartPos.length;i++) S]e~)IgO  
fileSplitterFetch.splitterStop(); +A&IxsTq5=  
8[{0X4y3  
+{ ,w#@  
} S'H0nJ3  
} c Gaz$=/  
//负责部分文件的抓取 xN":2qy#T  
**FileSplitterFetch.java 'AlSq:gZ  
*/ n!EH>'T  
package NetFox; 3:CQMZ|;@  
f T+n-B  
Wy0a2Ve  
import java.io.*; McMK|_H  
import java.net.*; _<' kzOj  
Vzv.e
6_  
}Rf:DmPE  
public class FileSplitterFetch extends Thread { "Ee/q:`  
c`N`xU+z  
BIB>U W  
String sURL; //File URL o^"d2=  
long nStartPos; //File Snippet Start Position 7l|>
  
long nEndPos; //File Snippet End Position MjF.>4  
int nThreadID; //Thread's ID R4J>M@-0v  
boolean bDownOver = false; //Downing is over 86) 3XE[5  
boolean bStop = false; //Stop identical =-B3vd:LF  
FileAccessI fileAccessI = null; //File Access interface Ot:\h  
]mGsNQ ].H  
FlA$G3  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ![MDmt5Ub^  
{ h"Yqm"U/  
this.sURL = sURL; N#6A>  
this.nStartPos = nStart; H)}1
xQ{3F  
this.nEndPos = nEnd; gQcr'[[a  
nThreadID = id; Qak@~b  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 E'kQ  
} z$im4'\c  

O|g!Y(  
*fy`
JC
 
public void run() F|ML$  
{ S:GUR6g8D  
while(nStartPos < nEndPos && !bStop) C?c-V,  
{ p?gLW/n  
g)G7 kB/<p  
SO jDtZ  
try{ HjY-b*B  
URL url = new URL(sURL); dvdBRrf  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); DEeL48{R  
httpConnection.setRequestProperty("User-Agent","NetFox"); xo"4mbTV  
String sProperty = "bytes="+nStartPos+"-"; 5Vm}<8{  
httpConnection.setRequestProperty("RANGE",sProperty); QCY{D@7T  
Utility.log(sProperty); So]FDd  
9+;f1nV  
nO7o7bc  
InputStream input = httpConnection.getInputStream(); (P!reYyM  
//logResponseHead(httpConnection); {&j{V-}f  
#$z-]i  

n|`):sP  
byte[] b = new byte[1024]; %'~<:>:"E  
int nRead; &CP@] pi9L  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .g`*cDW^=  
{ :phD?\!w8t  
nStartPos += fileAccessI.write(b,0,nRead); eR 2T<7G  
//if(nThreadID == 1) JFk|Uqs(  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _q 9lr8hx  
} QNI|h;D  
WD do{  
z# ?w/NE  
Utility.log("Thread " + nThreadID + " is over!"); y Q @=\'  
bDownOver = true; EqDYQ 7  
//nPos = fileAccessI.write (b,0,nRead); u9^;~i,  
} qQRYHo>/e  
catch(Exception e){e.printStackTrace ();} *UxB`iA  
} bOGDz|H``  
} Ch!Q?4  
|+=:x]#vV  
3jdB8a]T_  
//打印回应的头信息 <cOE6;d#  
public void logResponseHead(HttpURLConnection con) uV:uXQni``  
{ 7[<sl35  
for(int i=1;;i++) &,kB7r"  
{ I;4Cv
oT  
String header=con.getHeaderFieldKey(i); }AfPBfgC1z  
if(header!=null) #CP, \G  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); \gQ+@O&+  
Utility.log(header+" : "+con.getHeaderField(header)); _89G2)U=C  
else fQA)r  
break; i/EiUH/~  
} 2o5<nGn  
} A,[m=9V  
RV*Zi\-X  
fJlN'F7  
public void splitterStop() MAo,PiYb  
{ 5GxM?%\  
bStop = true; KKXb,/  
} U8Jj(]},_  
5BO!K$6  
U)1qsUDF  
} P87Fg  
*TI6Z$b|6  
e Em0c]]9  
/* qtQ:7WO  
**FileAccess.java r.5Js*VX!  
*//文件访问(定位，写) Kj|F  
package NetFox; %+"AF+c3r  
import java.io.*; kGeME   
utS Mx(  
#zD+DBTAu  
public class FileAccessI implements Serializable{ ,#;ahwU~s  
IL"#TKKv  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 E4ee_`p  
RandomAccessFile oSavedFile; fy4JW,c  
long nPos; htSk2N/  
#_|^C(]!  
k<hO9;#qpL  
public FileAccessI() throws IOException I~6 ;9TlQ  
{ d>-EtWd  
this("",0); z2zp c^i  
} `7n,(  
u"|nu!p`  
`8bp6}OD,  
public FileAccessI(String sName,long nPos) throws IOException xEWa<P#.u  
{ /7)G"qG~F~  
oSavedFile = new RandomAccessFile(sName,"rw"); 7+-}8&syu  
this.nPos = nPos; Rp9iX~A`e  
oSavedFile.seek(nPos); S60`'!y  
} sgsMlZ3/  
<W^~Y31:0  
KePHn:c  
public synchronized int write(byte[] b,int nStart,int nLen) 0].5[Jo  
{ 'Em($A(  
int n = -1; UzwIV{  
try{ )U`kU`+'  
oSavedFile.write(b,nStart,nLen); Tj+WO6#V  
n = nLen; 5X-{|r3q  
} !]T|=yw  
catch(IOException e) '(>N gd[  
{ ?`}U|]c  
e.printStackTrace (); t\0JNi$2  
} m_f^#:  
&!MKqJ@t  
hlEvL  
return n; 5Ozj&Zq  
} 86VuPV-  
2*F
Z@?X@r  
3=I Q  
} C@W0fz  
5toNEDN  
46`{mPd{aO  
/* a]ey..m  
**SiteInfoBean.java T^>cT"ux_  
*/ #2=30  
package NetFox; C`K/ai{4  
QKQy)g  
akwVU\RP  
public class SiteInfoBean { ArMe[t0$  
z [{%.kA  
@@&;gWr;  
private String sSiteURL; //Site's URL $6Psq=|  
private String sFilePath; //Saved File's Path i:To8kdO  
private String sFileName; //Saved File's Name `Y9@?s Q  
private int nSplitter; //Count of Splited Downloading File ?-i&6i6Y  
h2K  
*i90[3l  
public SiteInfoBean() JH9CN  
{//nSplitter的缺省值为5 )63w&  
//default value of nSplitter is 5 dksnW!  
this("","","",5); ar%Rr"  
} Hqv(X=6E0  
]F!,Jx  
}=5(*Vg  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) J{I?t~u  
{ wDzS<mm  
sSiteURL= sURL; s3S73fNOk  
sFilePath = sPath; LdV_7)  
sFileName = sName; <jjaqDSmz  
this.nSplitter = nSpiltter; K;O\Pd  
YTsn;3d]}  
+(T,d]o]  
} .v'8G)6g  
PeZ=ONY5  
K+H82$ #  
public String getSSiteURL() `. Z".
  
{ s RB8 jY  
return sSiteURL; 6iOAYA=  
} 0jq#,p=l;  
Hr'#
0fW  
F
u)7J4Z  
public void setSSiteURL(String value) ) Lv{  
{ iFnM6O$(  
sSiteURL = value; yuWrU<Kw  
} bK7DGw`1  
8cl!8gfv  
3dfSu'  
public String getSFilePath() +{&g|V  
{ |RdSrVB  
return sFilePath; 2*N# %ZUX  
} '=xl}v  
"wc $'7M  
~j_H2+!  
public void setSFilePath(String value) z;)% i f6  
{ pw8'+FX  
sFilePath = value; l\)Q3.w  
} LBzpaLd  
X^`ld&^*({  
]|oqJ2P  
public String getSFileName() u Wtp2]A  
{ C" {j0X`  
return sFileName; u]"RAH  
} )yJjJ:re  
l}{O  
(s~hh  
public void setSFileName(String value) HukHZ;5  
{ GZo^0U,;  
sFileName = value; Aka`L
:k  
} $J+$8pA  
mDhU wZH  
1Pbp=R/7ar  
public int getNSplitter() .(krB%N  
{ <qu\q \  
return nSplitter; UqH7ec  
} LcXrD+ 1  
tpS F[W  
8LOzL,Ah  
public void setNSplitter(int nCount) 94+#6jd e  
{ ??4QDa-  
nSplitter = nCount; ck;owGlT  
} %rYt; 7B  
} Mg].#  
iV%%VR8b  
!eW<4jYB  
/* a2zo_h2R  
**Utility.java %(i(ZW "  
*/ m@~HHwj  
package NetFox; /*[a>B4-q  
V6c?aZ,O  
8w$cj'  
public class Utility { z&eJ?wb  
PO#FtG  
FU<rE&X2:  
public Utility() }k%>%xQ.  
{ }rN"H4)  
_=
rXaTp  
d 1z   
} {)G3*>sG3  
>?5`F
C  
//线程睡眠 .Xr_BJ _  
public static void sleep(int nSecond) {\k9%2V*+  
{ Mc.KLz&,FC  
try{ d(&vIjy  
Thread.sleep(nSecond); T]+*}C  
} 6;VlX,,j  
catch(Exception e) YWTo]DJV  
{ Mcf
SB(59  
e.printStackTrace (); /g21.*Z  
} 3.>jagu  
} <1ai0]  
HtMlSgx,8>  
//日志 oY{*X6:6<  
public static void log(String sMsg) o)NWsUXf  
{ {KR/
TQ?A  
System.err.println(sMsg); W1
#3+  
} {T$;BoR#O  
x9uA@$l^|
 
 iGR(  
public static void log(int sMsg) bf3)^ 49}  
{ 4>(?R[:p)  
System.err.println(sMsg); #df Aqg'  
}
a-7nA  
} WvR}c  
UHXlBH@  
%o~zsIl  
/* i
;)88  
**TestMethod.java 1r@v \#P  
*/ ! $n^Ze2 !  
package NetFox; h~dM*yo;  
-WEiY  
GSl\n"S]=  
public class TestMethod { U5Rzfm4  
}D0j%~&"e  
`W"-jz5#=  
public TestMethod() $ \jly  
{ ///xx/weblogic60b2_win.exe WS;3a}u  
try{ 8z@A/$T  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,2u]rLxx;  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); A+?n=IHh  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ]t<%v_K  
fileFetch.start(); /+'@}u |  
} -5.>9+W8I  
catch(Exception e){e.printStackTrace ();} w+}KX><r  
_,vJ0{*  
F|V?Z  
} 9)
wjVk  
rBpr1XKl,  
)Y)7p//  
public static void main(String[] args) wd u>3Ch"y  
{ SJw0y[IL6(  
new TestMethod(); |]Ockg[
  
} vhT9#) HI  
} L[IjzxUv  
点击下载更多相关资料