public File writeString2File(String Data, String filePath,Logger log)
 
{
 
BufferedReader bufferedReader = null;
 
BufferedWriter bufferedWriter = null;
 
File distFile=null;
 
try {
 
distFile= new File(filePath);
 
if (!distFile.getParentFile().exists()) distFile.getParentFile().mkdirs();
 
bufferedReader = new BufferedReader(new StringReader(Data));
 
bufferedWriter = new BufferedWriter(new FileWriter(distFile));
 
char buf[] = new char[1024]; //字符缓冲区
 
int len;
 
while ((len = bufferedReader.read(buf)) != -1)
 
{
 
bufferedWriter.write(buf, 0, len);
 
}
 
bufferedWriter.flush();
 
bufferedReader.close();
 
bufferedWriter.close();
 
} catch (Exception e) {
 
log.info("信息写入临时文件出错"+e.toString());
 
e.printStackTrace();
 
}
 
return distFile;
 
}

 
本篇介绍了java实现文件保存到本地的方法，具体代码如下：
 
private void savepic(inputstream inputstream, string filename) {
 
outputstream os = null;
 
try {
 
string path = "d:\\testfile\\";
 
// 2、保存到临时文件
 
// 1k的数据缓冲
 
byte[] bs = new byte[1024];
 
// 读取到的数据长度
 
int len;
 
// 输出的文件流保存到本地文件
 
file tempfile = new file(path);
 
if (!tempfile.exists()) {
 
tempfile.mkdirs();
 
}
 
os = new fileoutputstream(tempfile.getpath() + file.separator + filename);
 
// 开始读取
 
while ((len = inputstream.read(bs)) != -1) {
 
os.write(bs, 0, len);
 
}
 
} catch (ioexception e) {
 
e.printstacktrace();
 
} catch (exception e) {
 
e.printstacktrace();
 
} finally {
 
// 完毕，关闭所有链接
 
try {
 
os.close();
 
inputstream.close();
 
} catch (ioexception e) {
 
e.printstacktrace();
 
}
 
}
 
}
 
文件保存方法.
 
附：
 
package com.ebways.web.upload.controller;
 
import java.io.*;
 
import java.text.simpledateformat;
 
import java.util.date;
 
import java.util.hashmap;
 
import java.util.map;
 
import com.ebways.web.base.basecontroller;
 
import org.springframework.stereotype.controller;
 
import org.springframework.web.bind.annotation.requestmapping;
 
import org.springframework.web.bind.annotation.requestparam;
 
import org.springframework.web.bind.annotation.responsebody;
 
import com.ebways.web.upload.url.uploadurl;
 
import org.springframework.web.multipart.multipartfile;
 
import javax.servlet.http.httpservletrequest;
 
import javax.servlet.http.httpservletresponse;
 
@controller
 
@requestmapping(value = uploadurl.mode_name)
 
public class uploadcontroller extends basecontroller {
 
@requestmapping(value = uploadurl.image_upload)
 
@responsebody
 
public string uploadfile(multipartfile file, httpservletrequest request, httpservletresponse response) throws illegalargumentexception, exception {
 
// 参数列表
 
map map = new hashmap<>();
 
map.put("file", file);
 
savepic(file.getinputstream(), file.getoriginalfilename());
 
//请求接口
 
string apireturnstr = "";//apihttprequest(map, api_host_url + "/image/upload");
 
return apireturnstr;
 
}
 
private void savepic(inputstream inputstream, string filename) {
 
outputstream os = null;
 
try {
 
string path = "d:\\testfile\\";
 
// 2、保存到临时文件
 
// 1k的数据缓冲
 
byte[] bs = new byte[1024];
 
// 读取到的数据长度
 
int len;
 
// 输出的文件流保存到本地文件
 
file tempfile = new file(path);
 
if (!tempfile.exists()) {
 
tempfile.mkdirs();
 
}
 
os = new fileoutputstream(tempfile.getpath() + file.separator + filename);
 
// 开始读取
 
while ((len = inputstream.read(bs)) != -1) {
 
os.write(bs, 0, len);
 
}
 
} catch (ioexception e) {
 
e.printstacktrace();
 
} catch (exception e) {
 
e.printstacktrace();
 
} finally {
 
// 完毕，关闭所有链接
 
try {
 
os.close();
 
inputstream.close();
 
} catch (ioexception e) {
 
e.printstacktrace();
 
}
 
}
 
}
 
/**
 
* 
 
* 功能：公共action
 
* 
 
*
 
* @date 2016年9月8日
 
* @author wangsheng
 
*/
 
private string allowsuffix = "jpg,png,gif,jpeg";//允许文件格式
 
private long allowsize = 2l;//允许文件大小
 
private string filename;
 
private string[] filenames;
 
public string getallowsuffix() {
 
return allowsuffix;
 
}
 
public void setallowsuffix(string allowsuffix) {
 
this.allowsuffix = allowsuffix;
 
}
 
public long getallowsize() {
 
return allowsize * 1024 * 1024;
 
}
 
public void setallowsize(long allowsize) {
 
this.allowsize = allowsize;
 
}
 
public string getfilename() {
 
return filename;
 
}
 
public void setfilename(string filename) {
 
this.filename = filename;
 
}
 
public string[] getfilenames() {
 
return filenames;
 
}
 
public void setfilenames(string[] filenames) {
 
this.filenames = filenames;
 
}
 
/**
 
* 
 
* 功能：重新命名文件
 
* 
 
*
 
* @return
 
* @author wangsheng
 
* @date 2016年9月8日
 
*/
 
private string getfilenamenew() {
 
simpledateformat fmt = new simpledateformat("yyyymmddhhmmsssss");
 
return fmt.format(new date());
 
}
 
/**
 
* 
 
* 功能：文件上传
 
* 
 
*
 
* @param files
 
* @param destdir
 
* @throws exception
 
* @author wangsheng
 
* @date 2014年9月25日
 
*/
 
public void uploads(multipartfile[] files, string destdir, httpservletrequest request) throws exception {
 
string path = request.getcontextpath();
 
string basepath = request.getscheme() + "://" + request.getservername() + ":" + request.getserverport() + path;
 
try {
 
filenames = new string[files.length];
 
int index = 0;
 
for (multipartfile file : files) {
 
string suffix = file.getoriginalfilename().substring(file.getoriginalfilename().lastindexof(".") + 1);
 
int length = getallowsuffix().indexof(suffix);
 
if (length == -1) {
 
throw new exception("请上传允许格式的文件");
 
}
 
if (file.getsize() > getallowsize()) {
 
throw new exception("您上传的文件大小已经超出范围");
 
}
 
string realpath = request.getsession().getservletcontext().getrealpath("/");
 
file destfile = new file(realpath + destdir);
 
if (!destfile.exists()) {
 
destfile.mkdirs();
 
}
 
string filenamenew = getfilenamenew() + "." + suffix;//
 
file f = new file(destfile.getabsolutefile() + "\\" + filenamenew);
 
file.transferto(f);
 
f.createnewfile();
 
filenames[index++] = basepath + destdir + filenamenew;
 
}
 
} catch (exception e) {
 
throw e;
 
}
 
}
 
/**
 
*功能：文件上传
 
*
 
* @param file
 
* @param destdir
 
* @throws exception
 
* @author wangsheng
 
* @date 2016年9月8日
 
*/
 
public void upload(multipartfile file, string destdir, httpservletrequest request) throws exception {
 
string path = request.getcontextpath();
 
string basepath = request.getscheme() + "://" + request.getservername() + ":" + request.getserverport() + path;
 
try {
 
string suffix = file.getoriginalfilename().substring(file.getoriginalfilename().lastindexof(".") + 1);
 
int length = getallowsuffix().indexof(suffix);
 
if (length == -1) {
 
throw new exception("请上传允许格式的文件");
 
}
 
if (file.getsize() > getallowsize()) {
 
throw new exception("您上传的文件大小已经超出范围");
 
}
 
string realpath = request.getsession().getservletcontext().getrealpath("/");
 
file destfile = new file(realpath + destdir);
 
if (!destfile.exists()) {
 
destfile.mkdirs();
 
}
 
string filenamenew = getfilenamenew() + "." + suffix;
 
file f = new file(destfile.getabsolutefile() + "/" + filenamenew);
 
file.transferto(f);
 
f.createnewfile();
 
filename = basepath + destdir + filenamenew;
 
} catch (exception e) {
 
throw e;
 
}
 
}
 
}
 
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持萬仟网。
 
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前端使用layui的图片上传，将文件base64编码，然后在后端使用转码类来操作base64编码，并保存图片到本地，继而获取文件地址，将文件地址保存到数据库中
 
1.使用layui的图片上传
 
infoset.jsp
 
layui.use('upload', function() {
 
var $ = layui.jquery;
 
var upload = layui.upload;
 
//普通图片上传
 
var uploadInst = upload.render({
 
elem: '#test1',
 
//根据id上传图片
 
url: 'http://localhost:8080/user?method=updateUserPhoto&id='+id, //改成您自己的上传接口
 
method: 'post' , //可选项。HTTP类型，默认post
 
auto: false, //选择文件后不自动上传
 
bindAction: '#ListAction' ,//指向一个按钮触发上传
 
choose: function(obj){
 
//将每次选择的文件追加到文件队列
 
var files = obj.pushFile();
 
//预读本地文件，如果是多文件，则会遍历。(不支持ie8/9)
 
obj.preview(function(index, file, result) {
 
console.log(index); //得到文件索引
 
console.log(file); //得到文件对象
 
console.log(result); //得到文件base64编码，比如图片
 
$('#demo1').attr('src', result); //图片链接(base64)
 
$.post("http://localhost:8080/user?method=updatePhoto", {result:result,id:id}, function(res) {
 
console.log("updatePhoto请求成功");
 
}, "text");//这里用的是post提交，如果不懂可以参考JQuery中ajax提
 
})
 
},
 
done: function(res) {
 
//如果上传失败
 
if (res.code > 0) {
 
return layer.msg('上传失败');
 
}
 
//上传成功
 
},
 
error: function() {
 
//演示失败状态，并实现重传
 
var demoText = $('#demoText');
 
demoText.html('上传失败 重试');
 
demoText.find('.demo-reload').on('click', function() {
 
uploadInst.upload();
 
});
 
}
 
});
 
});
 
2.后端使用编码类转码,保存图片到本地
 
UserServlet
 
String basedata=req.getParameter("result");
 
Integer useridtwo = Integer.parseInt(req.getParameter("id"));
 
System.out.println("UserServlet中使用方法updatePhoto获取数据为：" + basedata);
 
String position=PhotoUtils.GenerateImage(basedata,"reader");
 
//通过id存储地址
 
Reader readertwo = userService.findUserById(useridtwo);
 
//传递两个参数去取代返回值为是否成功保存地址
 
if (userService.updatePhoto(readertwo,position) == 1) {
 
System.out.println("updatePhoto数据更新成功");
 
}
 
PhotoUtils
 
import org.apache.commons.fileupload.FileItem;
 
import sun.misc.BASE64Decoder;
 
import java.io.File;
 
import java.io.FileOutputStream;
 
import java.io.OutputStream;
 
import java.util.Date;
 
public class PhotoUtils {
 
//base64字符串转化成图片
 
public static String GenerateImage(String imgStr,String wenjian)
 
{
 
System.out.print("已经收到了把字节码转化为图片的方法");
 
//对字节数组字符串进行Base64解码并生成图片
 
if (imgStr == null) //图像数据为空
 
return "error";
 
//解析base64码，获取图片格式
 
String str [] = imgStr.split(",");
 
imgStr = str[1];
 
String imgInfo = str[0];
 
String imgExt = imgInfo.split("/")[1].split(";")[0];
 
// String imgExt="gif";
 
BASE64Decoder decoder = new BASE64Decoder();
 
try
 
{
 
//Base64解码
 
byte[] b = decoder.decodeBuffer(imgStr);
 
for(int i=0;i
 
{
 
if(b[i]<0)
 
{//调整异常数据
 
b[i]+=256;
 
}
 
}
 
String imgFileReturn= "http://localhost:8080/image/"+getPhotoNewName(imgExt,wenjian);
 
String imgFilePath = "E:\\JavaProject\\bookManage\\web\\image\\"+"\\"+getPhotoNewName(imgExt,wenjian);//新生成的图片
 
// String imgFilePath = "E:\\image\\"+"\\"+getPhotoNewName(imgExt,wenjian);//新生成的图片
 
System.out.println(imgFilePath);
 
OutputStream out = new FileOutputStream(imgFilePath);
 
out.write(b);
 
out.flush();
 
out.close();
 
return imgFileReturn;
 
}
 
catch (Exception e)
 
{
 
return "";
 
}
 
}
 
/**
 
*这个函数的功能是获取当前时间点与1970年的间隔秒数
 
*/
 
public static int getSecondTimestamp(Date date){
 
if (null == date) {
 
return 0;
 
}
 
String timestamp = String.valueOf(date.getTime());
 
System.out.println(timestamp);
 
int length = timestamp.length();
 
if (length > 3) {
 
return Integer.valueOf(timestamp.substring(0,length-3));
 
} else {
 
return 0;
 
}
 
}
 
/**
 
*
 
*这个函数的功能是得到新的照片名称
 
*/
 
public static String getPhotoNewName(String imgExt,String wenjian) {
 
Date date=new Date();
 
int second=getSecondTimestamp(date);
 
String fileName=wenjian+String.valueOf(second)+"."+imgExt;
 
return fileName;
 
}
 
}
 
ReaderRepositoryImpl
 
@Override
 
public Reader findUserById(int id) {
 
//之前定义的包装类用于c3p0连接池的使用
 
Connection connection = JdbcTools.getConnection();
 
String sql = "select * from reader where id=?";
 
//执行sql语句
 
PreparedStatement statement = null;
 
ResultSet resultSet = null;
 
Reader reader = null;
 
try {
 
statement = connection.prepareStatement(sql);
 
//参数代替问号
 
statement.setInt(1,id);
 
resultSet = statement.executeQuery();
 
if (resultSet.next()) {
 
//单个数据的替代,
 
reader = new Reader(resultSet.getInt(1), resultSet.getString(2), resultSet.getString(3), resultSet.getString(4), resultSet.getString(5), resultSet.getString(6), resultSet.getString(7), resultSet.getInt(8), resultSet.getString(10));
 
}
 
} catch (SQLException e) {
 
e.printStackTrace();
 
} finally {
 
JdbcTools.release(connection, statement, resultSet);
 
}
 
return reader;
 
}

闲着无事，记一下String写入本地文件的方法，直接上代码：
 
	/**
	 * 保存文件到本地
	 * 
	 * @param urlString
	 * @param filename
	 * @param savePath
	 * @throws Exception
	 */
	public static void writeOcrStrtoFile(String result, String outPath, String outFileName) throws Exception {
		File dir = new File(outPath);
		if(!dir.exists()) {
			dir.mkdirs();
		}
		File txt = new File(outPath + "/" + outFileName);
		if (!txt.exists()) {
			txt.createNewFile();
		}
		byte bytes[] = new byte[512];
		bytes = result.getBytes();
		int b = bytes.length; // 是字节的长度，不是字符串的长度
		FileOutputStream fos = new FileOutputStream(txt);
//		fos.write(bytes, 0, b);
		fos.write(bytes);
		fos.flush();
		fos.close();
	}