http断点续传简单实现（java)

/* mufJ@YS#  
**SiteFileFetch.java @P@j9yR  
*/ H;.${u^lhd  
package NetFox; aIXN wnq  
import java.io.*; HJ]9e  
import java.net.*; U6/$CH<pe  
#o/  
#
D2.RN  
public class SiteFileFetch extends Thread { Y"dUxv1Ap  
X}@'FxIF  
)=]u]7p}  
SiteInfoBean siteInfoBean = null; //文件信息Bean -cL{9r&X  
long[] nStartPos; //开始位置 ;[,r./XmH  
long[] nEndPos; //结束位置 f+xhS,i
DR  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4[o/p8*/  
long nFileLength; //文件长度 cU  
boolean bFirst = true; //是否第一次取文件 c?H@HoF  
boolean bStop = false; //停止标志 6myF!  H=  
File tmpFile; //文件下载的临时信息 (n+FEE<  
DataOutputStream output; //输出到文件的输出流 @3_[NI%  
ys~oJb~  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ZFH;  
public SiteFileFetch(SiteInfoBean bean) throws IOException :*6#(MX  
{ ,u&K(Z%  
siteInfoBean = bean; |Y")$pjz  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); W8>
<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 6PyODW;R/5  
if(tmpFile.exists ()) P1>?crw  
{ bAVlL&^@|  
bFirst = false; b Y^K)0+^s  
read_nPos(); 8v V<A*`  
} *@(j'0hj  
else @?!&M c2  
{ }3DZ`8u  
nStartPos = new long[bean.getNSplitter()]; abgAUg)  
nEndPos = new long[bean.getNSplitter()]; X<*-d6?gD`  
} r;C BA'Z  
W~i599!v  
(aTpBXGr=  
n=8DC&  
} Ak'=/`+p  
-D&d1`N4  
Ej
Dr   
public void run() qQ T^d  
{ Mr6q7  
//获得文件长度 l?Qbwv}  
//分割文件 D]StDOmM  
//实例FileSplitterFetch "
t!_bma  
//启动FileSplitterFetch线程 N}rc3d#  
//等待子线程返回 XKQ\Ts2<k  
try{ !0DOj["  
if(bFirst) MLk
%U 4  
{ WLkfo6Nw  
nFileLength = getFileSize(); `vc?*"  
if(nFileLength == -1) sb"h:i>O4  
{ P3op1/Np  
System.err.println("File Length is not known!"); +F@ZVMp  
} IQNvhl.{  
else if(nFileLength == -2) cI/
Puh^3  
{ UJ^MS4;I3  
System.err.println("File is not access!"); 8^2E77s4U  
} 3:ELYn  
else V|`w/P9g4  
{ *\
"+/
 
for(int i=0;i<nStartPos.length;i++)
,JONc9  
{ ;cD&qheDV  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ..a@9#D  
} U3OX
O1  
for(int i=0;i<nEndPos.length-1;i++) L[aA4`  
{ 55K(]%t  
nEndPos = nStartPos[i+1]; l1uv]t <  
} /)/>/4O  
nEndPos[nEndPos.length-1] = nFileLength; &(/QJ`*8  
} 7S.E,\Tws  
} $s`#&.>c-  
m(rd\3d  
^W*3S[-`g  
//启动子线程 FL?Ndy"I  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; h4geoC_W2  
for(int i=0;i<nStartPos.length;i++) Wa!}$q+  
{ Cj1nll8c  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -*AUCns#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }F=lG-x  
nStartPos,nEndPos,i); .h=H?Hr(V]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m#a1N  
fileSplitterFetch.start(); =}wqo6Bn|  
} g7@.Fa.u'!  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2{oU5e  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "^&Te%x_b  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]G
H_;  
nEndPos = " + nFileLength); gt|:K)[,6  
// fileSplitterFetch[nPos.length-1].start(); q
)QM+4  
RM6*c .  
]3&BLq  
//等待子线程结束 /P koqA,  
//int count = 0; }Jm~b9j  
//是否结束while循环 D\-D~G]x  
boolean breakWhile = false; >#EOCo  
+5xk6RP   
I6lWB(H!u  
while(!bStop) (>M? iB  
{ Gq0Q}[53  
write_nPos(); CEl9/"0s6  
Utility.sleep(500); _4-UM2o;  
breakWhile = true; ;!Q}g19C  
s^zX9IVnp  
3Xl!Z^W  
for(int i=0;i<nStartPos.length;i++) :{'%I#k2  
{ .X;DI<K  
if(!fileSplitterFetch.bDownOver) Qoom[@$  
{ ;+(EmD:Q  
breakWhile = false; .g8db d  
break; k#DMd9
 
} mr<camL5  
} MCO`\"`l  
if(breakWhile) C<yjGtVD  
break; G^&P'*  
b 67l\L  
cu )w6!f  
//count++; #Zj3SfU~`  
//if(count>4) .ovG_O  
// siteStop(); 4ZCD@C  
} >&D}^TMYY  
Xcw6mpLt  
V8-*dE  
System.err.println("文件下载结束！"); Q~zs]{\  
} ~Hb2-V  
catch(Exception e){e.printStackTrace ();} t*(buAx  
} @;`d\lQ  
"U o~fJ  
2!Sl!x+i\'  
//获得文件长度 Y"UB\_=  
public long getFileSize() u=f}t=3  
{ K(75)/  
int nFileLength = -1; |$G|M=*LN  
try{ }[b3$WZ  
URL url = new URL(siteInfoBean.getSSiteURL()); D0VbD" y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A40Q~X  
httpConnection.setRequestProperty("User-Agent","NetFox"); [Nv)37|W  
g\Akf  
..;ep2jSs  
int responseCode=httpConnection.getResponseCode(); s_4y^w]aX  
if(responseCode>=400) "pTU&He  
{ ),5|Ves;t[  
processErrorCode(responseCode); cg).b?g  
return -2; //-2 represent access is error &at>sQ'  
} ]%eyrbU  
91\]Dg  
Bhg,P.7  
String sHeader; 'h3yxf}\  
 ?~=5x  
K_o[m!:jU  
for(int i=1;;i++) u5rHQA0%  
{ :)DvZxHE@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ZIs=%6""&  
//Utility.log(in.readLine()); S:{`eDk\A_  
sHeader=httpConnection.getHeaderFieldKey(i); kj/v$m  
if(sHeader!=null) |<!xD iB  
{ iCNJ%AZH  
if(sHeader.equals("Content-Length")) I~)A!vp  
{ nl+8C}=u  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ,KFF[z  
break; k<QZ_*x}G  
} f?W"^6Df  
} .M([
n-  
else *_H^]wNJG  
break; aK?PK }@  
} ykD-
L^}  
} 
4`'V%)M  
catch(IOException e){e.printStackTrace ();} 0P^&{ek+)  
catch(Exception e){e.printStackTrace ();} Qv;q*4_  
X1FKcWv  
"] [u  
Utility.log(nFileLength); *yqke<o9)  
Wo7`gf_(  
tJ9gwx7Pg  
return nFileLength; ZYs?65.  
} <8YIQA  
!P@4dG  
0s.X  
//保存下载信息（文件指针位置） 1BOv|xPjZ  
private void write_nPos() EFzPt?l  
{ FJ{6_=@D  
try{ 6ac_AsFK  
output = new DataOutputStream(new FileOutputStream(tmpFile)); {+jO/ZQu5  
output.writeInt(nStartPos.length); Q3rLCg,;  
for(int i=0;i<nStartPos.length;i++) @j'GcN vs  
{ c_Jcy  
// output.writeLong(nPos); 1{.5X8y1x  
output.writeLong(fileSplitterFetch.nStartPos); Y{g[LG`U  
output.writeLong(fileSplitterFetch.nEndPos); J!d=aGY0-  
} 9T%b#~?3P  
output.close(); NKMVp/66D  
} d-'BT(@:  
catch(IOException e){e.printStackTrace ();} r;@"s g  
catch(Exception e){e.printStackTrace ();} FE3uNfQs|  
} 2U&+K2  
x<1t/o  
#+(@i|!ifo  
//读取保存的下载信息（文件指针位置） N ,nvAM  
private void read_nPos() UY^TTRrH  
{ \:9<d@?  
try{ VfkQc$/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); L7n
W_  
int nCount = input.readInt(); >/G[Oo  
nStartPos = new long[nCount]; z yrjb8  
nEndPos = new long[nCount]; ,*Wp$  
for(int i=0;i<nStartPos.length;i++) %hi]oz  
{ &?Z<"+B8S  
nStartPos = input.readLong(); <6.?:Jj  
nEndPos = input.readLong(); 4P}d/w?'KL  
} y/;DA=  
input.close(); dZuPR  
} Mw|lEctN0  
catch(IOException e){e.printStackTrace ();} hp$1c  
catch(Exception e){e.printStackTrace ();} |>Pz#DCy  
} ZDx1v_xr  
7[:?VXQ  
l
._g[qa  
private void processErrorCode(int nErrorCode) 'tJxADK  
{ BMItHn].  
System.err.println("Error Code : " + nErrorCode); <z8z\4Hz  
} : $N43_
Wb  
mNKcaM?h  
@`XbM7D 5  
//停止文件下载 EAV6qW\r5]  
public void siteStop() h(p cGE  
{
O:Wd ,3_  
bStop = true; p<c1$O*  
for(int i=0;i<nStartPos.length;i++) J+l#!gk$!  
fileSplitterFetch.splitterStop(); &Xh=bM'/%m  
uTNy{RBD+  
aj]pN,g@N  
} KN'twPFq  
} \0.!al0  
//负责部分文件的抓取 K6stkDhb  
**FileSplitterFetch.java h>ZU67-   
*/ =\)76xC20  
package NetFox; !*PX
-  
N5mhs#  
ubQr[/  
import java.io.*; EOXuc9>G  
import java.net.*;
[~ !9t9+~  
*0Wkz
'=U  
J3hhh(  
public class FileSplitterFetch extends Thread { V$bq|r  

\-D[C+1(  
jJAr #|  
String sURL; //File URL Z_s]2y1  
long nStartPos; //File Snippet Start Position F%$lcQ04%  
long nEndPos; //File Snippet End Position lcXo
>  
int nThreadID; //Thread's ID  `l  
boolean bDownOver = false; //Downing is over F&HvSt}l5  
boolean bStop = false; //Stop identical _mTNK^gB  
FileAccessI fileAccessI = null; //File Access interface `2`h4[^ [X  
)3^#C
D  
}ISR +./+  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException qRXHaQi@9  
{ \m(>Q  
this.sURL = sURL; MbeK{8~E%l  
this.nStartPos = nStart; &?# YjU"  
this.nEndPos = nEnd; #>2cfZ`6'J  
nThreadID = id; LBIEG_/m  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 l $0w 9Z^  
} Awe'MGp%  
7%W@Hr,%F  
ihD|e&  
public void run() G%U!$\j:qd  
{ 0%qM`KZC  
while(nStartPos < nEndPos && !bStop) |-xKH.'n  
{ *~^%s+b  
5
")BCA  
d>wG6Z,|  
try{ g{JH5IZ~  
URL url = new URL(sURL); 
[6)vD@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 99~ZZG  
httpConnection.setRequestProperty("User-Agent","NetFox"); QB*n [(?  
String sProperty = "bytes="+nStartPos+"-"; 4KY@y?H g  
httpConnection.setRequestProperty("RANGE",sProperty); e?WI=Og  
Utility.log(sProperty); P_(<?0l  
-^t&U] g  
TIxlLOs
 
InputStream input = httpConnection.getInputStream(); F6"QsFG  
//logResponseHead(httpConnection); =z'533C  
m Gx{Vpt  
$x2G/
5?  
byte[] b = new byte[1024]; mxICQ>s b  
int nRead; - XB[2h  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) A:*$rHbzl  
{ EGjzjuJu{  
nStartPos += fileAccessI.write(b,0,nRead); AjINO}b  
//if(nThreadID == 1) ~>$z1o&}.  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ' wKTWmf?\  
} Pt7C/ qM/  
1~vv<`-  
ZVz*1]}  
Utility.log("Thread " + nThreadID + " is over!"); /Q'O]h0a  
bDownOver = true; le2 v"Y  
//nPos = fileAccessI.write (b,0,nRead); -l{ wB"  
} TSj)XU {W  
catch(Exception e){e.printStackTrace ();} \b?O+;5Cj  
} XlJ+:st  
} 1~[GGl  
~e=KBYDBu  
S9 @*g3  
//打印回应的头信息 5K00z?kD2V  
public void logResponseHead(HttpURLConnection con) Y{L|ja%9?  
{ 10
*^  
for(int i=1;;i++) wV'_{/WM  
{ =<U'Jtu6'  
String header=con.getHeaderFieldKey(i); e)oi3d.wJf  
if(header!=null) \oO&c  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); F2v9XMi  
Utility.log(header+" : "+con.getHeaderField(header));
\$ :)Ka  
else E#n:d9WA:  
break; f0g&=k{OD  
} \8`^QgV`@  
} EI@ep~  
kv`5"pa7M  
+'UxO'v3]  
public void splitterStop() t_Ul;HVPS  
{ \p\rPfY{>  
bStop = true; dq3"L!0u  
} aWb5w  
WiFZY*iu5  
>k(AQW5?  
} y|YhDO  
=GLMdhD]  
%j?7O00@  
/* >c.HH}O0W  
**FileAccess.java l6!a?C[2T  
*//文件访问(定位，写) r`C t/]c  
package NetFox; Y4*?QBYA  
import java.io.*; *'R2Lo<C  
>IHf5})R  
E9j(%kQ2  
public class FileAccessI implements Serializable{ j{P3o<l&`  
0vM,2:kf*  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ;+Mr|vweTC  
RandomAccessFile oSavedFile; DkBVk+  
long nPos; e3kdIOu5  
IE&G7\>(yO  
Zh_P  
public FileAccessI() throws IOException < !]7Gt  
{ AI2>{V  
this("",0); VM"*@T  
} 7s1LK/R|u  
NjSjE_S2B8  
 34~[dY  
public FileAccessI(String sName,long nPos) throws IOException cS"P
IelR  
{ {1W
,-%  
oSavedFile = new RandomAccessFile(sName,"rw"); %$F\o1S  
this.nPos = nPos; sUsIu,1Q  
oSavedFile.seek(nPos); .,SWa;[iB  
} \K(# r=  
dH0wVI<z  
x[2eA!NC  
public synchronized int write(byte[] b,int nStart,int nLen) &qZ:"k  
{ @fSqGsSk  
int n = -1; ,YmTx  
try{ )X-TJ+d  
oSavedFile.write(b,nStart,nLen); YCNpJGM  
n = nLen; ~

*P9_<  
} ~ph>?xuw  
catch(IOException e) |C;*GeyS;J  
{ ow,=M%x"0  
e.printStackTrace (); +#ANc;2g  
} ;,:w%.  
LzkwgcR  
[T#9#3  
return n; Mhg_z.Z  
} L
@6T~
 
F% K}&3  
7(KVA1P66  
} S31+ j
:"  
)rv<"  
84maX'  
/* k'+Mc%pg4E  
**SiteInfoBean.java ]}dAm S/  
*/ !:Clzlg  
package NetFox; Q GDfX_  
kM/;R)3t4/  
;923^*\:F{  
public class SiteInfoBean { >zB0+l  
I?i,21:5  
JV9Ft,xk  
private String sSiteURL; //Site's URL X.!|#FWb+  
private String sFilePath; //Saved File's Path e5fzV.'5  
private String sFileName; //Saved File's Name $9O%,
U@  
private int nSplitter; //Count of Splited Downloading File :[7.YQ   
}K\m.+%=d  
< 5#}EiT5  
public SiteInfoBean() { Sn J  
{//nSplitter的缺省值为5 SiSxym  
//default value of nSplitter is 5 -pm^k-%v  
this("","","",5); bn<}  
} {V~Gr  
5R7DD5c[  
_ ?Z :m  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *Ldno`1O  
{ C8.MoFfhe  
sSiteURL= sURL; =qVD"Z]z  
sFilePath = sPath; ?]u=5gqUU  
sFileName = sName; {H%1sI  
this.nSplitter = nSpiltter; 0CRk&_ht  
~b.e9FhdA  
S4BU!  
} Nb@zn0A(;  
%QrpFE5V5  
au 5qbP  
public String getSSiteURL() 9q!./)  
{ xBi``x2eY  
return sSiteURL; ]pP [0S  
} 9~$'?  
Gfn?1Kt{  
?_7^MP>  
public void setSSiteURL(String value) itW~2#nJz  
{ Ro|%pT  
sSiteURL = value; Rck k  
} :IlJQ{=W  
)S6"I  
^J Y]w^u  
public String getSFilePath() 73OYHp_j  
{ (Cjw^P|Y@  
return sFilePath; uKocEWB=/F  
} H '(Ky  
Bys_8x}  
1Qz1 Ehz>  
public void setSFilePath(String value) CERT`W%o  
{ ;v^1V+1:z  
sFilePath = value; J 4OgV?  
} 3fWL}]{<a  
h\i>4^]X.  
^w|apI~HSE  
public String getSFileName() c/G]r|k  
{ Y^@Nvt$<K  
return sFileName; R3=]Av46  
} Fxr$j\bm  
D27MT/=7  
J#^oUq  
public void setSFileName(String value) i+HHOT  
{ x<%V&<z1g  
sFileName = value; Lk~aMbw#  
} }\Mmp+<  
o7W
1sD1O  
\6U$kMGde  
public int getNSplitter() $pg1Av7l  
{ yl[6b1  
return nSplitter; bM"crRG"  
} ZeyAbo  
`vPc&.
-K  
w,QO!)j!  
public void setNSplitter(int nCount) 0'9zXJ"  
{ 5E!G
  
nSplitter = nCount; >1n[Y- r  
} H(TY.  
} ]TmxCTVL  
!:^lTvYWZH  
q|+`ihut  
/* e):rr*  
**Utility.java B:Xmc,|,  
*/ 7#BUd/  
package NetFox; M'4$z^@Z  
qJZ5w}  
7pY7iR_  
public class Utility { D8''q%  
V 2WcPI^  
*To
5\|  
public Utility() (;@\gRL  
{ E5J2=xVW#  

BL^8gtdn  
Z`)}1|~B  
} |Vs?yW  
<8Zm}-U  
//线程睡眠 nrpxZA  
public static void sleep(int nSecond)  \tWFz(  
{ lp;=f  
try{ D!oELZ3  
Thread.sleep(nSecond); ,{br6*E
 
} GDW$R`2  
catch(Exception e) Ux
yj\p  
{ _s_%}8
o  
e.printStackTrace (); *uq}jlD`!  
} 3bi,9 >%  
} ?Hd/!I&  
mw*BaDN@Q  
//日志 #&cNR_"w  
public static void log(String sMsg) ?
U`~,oI0  
{ RN%*3{-  
System.err.println(sMsg); UpU2H4  
} R}-<ZJe  
dk^Uf84.Gr  
kCu"G  
public static void log(int sMsg) }RvP*i  
{ oe
8six
Z[  
System.err.println(sMsg); L/VlmN_v>s  
}
^U`Bj*"2  
} VHlN;6Qlff  
-W:te7  
,L"1Ah  
/* |9F^"7Q~C  
**TestMethod.java w<ol$2&B  
*/ / ao|v  
package NetFox; 2V1|b`b#4  
Z7X_U`Q  
wewYlm5@  
public class TestMethod { .cV<(J 5o  
gJ8+HV  
mQ@A3/=`  
public TestMethod() uP-I7l0i1  
{ ///xx/weblogic60b2_win.exe
b5MCOW1+  
try{ VqeK~,}  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); J^J$I!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); U;7Cmti"  
SiteFileFetch fileFetch = new SiteFileFetch(bean); :|\{mo1NB  
fileFetch.start(); ]R$ u3F  
} I+?9}t  
catch(Exception e){e.printStackTrace ();} B3lP#ckh  
mct$.{~  
oA;s

P'  
} 02lI-xHe  
Vk/!_)  
^rmcyy8;g  
public static void main(String[] args) 'V=i;2mB*  
{ .FarKW  
new TestMethod(); l1&NU'WW  
} _i=431Z40  
} DaV:Slp9  
点击下载更多相关资料