‘编程学习’ 分类下的所有文章
2017九月15

使用Java API绘制验证码图片

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * 生成验证码,将验证码绘制成一张图片返回浏览器
 * 
 * @author FreeDroid
 *
 */
public class CheckcodeServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	public void service(HttpServletRequest request, 
              HttpServletResponse response) throws 
                     ServletException, IOException {
		/*
		 * step1.绘图
		 */
		Random r = new Random();
		//从getString()方法取出A-Z,0-9的指定长度随机字符串
		String number = getString(5);
		//先创建一个画布(内存映像对象)
		BufferedImage image = new BufferedImage(80, 30, BufferedImage.TYPE_INT_BGR);
		//获得画笔
		Graphics g = image.getGraphics();
		//给画笔设置颜色
		g.setColor(new Color(255, 255, 255));
		//给画布设置背景颜色
		g.fillRect(0, 0, 80, 30);
		//设置字体
		g.setFont(new Font(null, Font.BOLD|Font.ITALIC, 20));
		//给每个字符设置随机颜色,并画到画布上
		for (int i = 0; i < number.length(); i++) {
			//给画笔设置颜色
			g.setColor(new Color(r.nextInt(255),r.nextInt(255),r.nextInt(255)));
			//在画布上画字符
			g.drawString(String.valueOf(number.charAt(i)), i*15, 25);
		}
		//加一些干扰线
		for (int i = 0; i < 8; i++) {
			//给画笔设置颜色
			g.setColor(new Color(r.nextInt(255),r.nextInt(255),r.nextInt(255)));
			//在画布范围内画线
			g.drawLine(r.nextInt(80), r.nextInt(30), r.nextInt(80), r.nextInt(30));
		}
		
		/*
		 * step2.将图片压缩,然后输出
		 */
		//设置响应内容类型为JPEG格式的图片
		response.setContentType("image/jpeg");
		//获得字节输出流(图片是二进制数据)
		OutputStream os = response.getOutputStream();
		//将原始图片(image)按照指定的算法压缩(jpeg)
                //然后将压缩之后得到的字节写入response对象。
		javax.imageio.ImageIO.write(image, "jpeg", os);
		os.close();		
	}

	/**
	 * 随机生成指定长度的大写字母和数字组合
	 * @param length
	 * @return
	 */
	private String getString(int length) {
		StringBuilder str = new StringBuilder();
		Random r = new Random();
		//取出大写字母
		for (int i = 0; i < 26; i++) {
			str.append((char) ('A' + i));
		}
		//取出数字
		for (int i = 0; i < 10; i++) {
			str.append((char) ('0' + i));
		}
		//从字符串str随机取length个字符放进str2组成新的字符串
		StringBuilder str2 = new StringBuilder();
		for (int i = 0; i < length; i++) {
			str2.append(str.charAt(r.nextInt(str.length())));
		}
		return str2.toString();
	}
	
}
2017八月11

UTF-8中文字符编码和解码,用位运算实现

/**
 * UTF中文字符编码和解码
 * 中文字符占3个字节,前缀分别是:1110XXXX 10XXXXXX 10XXXXXX
 * 
 * @author FreeDroid
 *
 */
public class Utf8codeANDdecode {

	public static void main(String[] args) {
		int ch = '我';
		byte[] bytes = codeUTF8(ch);
		char ch2 = decodeUTF8(bytes);
		System.out.println(ch2);
	}

	/**
	 * 解码
	 * @param bytes
	 * @return
	 */
	public static char decodeUTF8(byte[] bytes) {
		int ch = (bytes[0]<<12&0xffff)|(bytes[1]<<6&0x3fff)|(bytes[2]&0x3f);
		return (char) ch;
	}
	
	/**
	 * 编码
	 * @param ch
	 * @return
	 */
	public static byte[] codeUTF8(int ch) {
		int b3 = ch & 0x3f | 0x80;
		int b2 = ch >>> 6 & 0x3f | 0x80;
		int b1 = ch >>> 12 & 0xf | 0xe0;
		return new byte[] { (byte) b1, (byte) b2, (byte) b3 };
	}

}
2017七月30

同名文件自动建立副本递归实现

public void newFile(File file){
	try {
		if (file.createNewFile()) {
			System.out.println("文件创建成功!");
		} else {
			String cName = changeName(file);
			File files = new File("." + File.separator + cName);
			newFile(files);
		}
	} catch (IOException e) {
		e.printStackTrace();
	}
}
public String changeName(File file) {
	String name = file.getName();
	int index = name.lastIndexOf('.');
	int index2 = name.lastIndexOf("_副本");
	if (index2 < 0) {
		return name.substring(0, index) + "_副本1" + name.substring(index);
	} else {
		String num = name.substring(index2+3, index);
		int i = Integer.valueOf(num)+1;
		return name.substring(0, index2) + "_副本" + i + name.substring(index);
	}
}
2017三月23

NutzWk: 微信AccessToken没有持久化造成超出调用限制的问题解决

1、wx_config 实体类添加三个字段,对应的表结构也要手动修改:


    @Column
    @Comment("access_token")
    @ColDefine(type = ColType.VARCHAR, width = 255)
    private String access_token;

    @Column
    @Comment("access_token_expires")
    @ColDefine(type = ColType.INT)
    private Integer access_token_expires;

    @Column
    @Comment("access_token_lastat")
    @ColDefine(type = ColType.VARCHAR, width = 50)
    private String access_token_lastat;

    get  set ...方法生成出来

2、nutzwx版本升级为1.r.61-SNAPSHOT

        <dependency>
            <groupId>org.nutz</groupId>
            <artifactId>nutzwx</artifactId>
            <version>1.r.61-SNAPSHOT</version>
        </dependency>


3、nutz版本升级为1.r.60

        <dependency>
            <groupId>org.nutz</groupId>
            <artifactId>nutz</artifactId>
            <version>1.r.60</version>
        </dependency>

4、WxConfigService 类getWxApi2替换为如下代码(主要是DaoAccessTokenStore从数据库取access_token)

    public WxApi2 getWxApi2(String wxid) {
        Wx_config appInfo = this.fetch(Cnd.where("id", "=", wxid));
        DaoAccessTokenStore myDaoAccessTokenStore = new DaoAccessTokenStore(dao());
        Map<String, Object> params = new HashMap<>();
        params.put("id", appInfo.getId());
        myDaoAccessTokenStore.setTableAccessToken("access_token");
        myDaoAccessTokenStore.setTableAccessTokenExpires("access_token_expires");
        myDaoAccessTokenStore.setTableAccessTokenLastat("access_token_lastat");
        myDaoAccessTokenStore.setFetch("select access_token,access_token_expires,access_token_lastat from wx_config where id=@id");
        myDaoAccessTokenStore.setUpdate("update wx_config set access_token=@access_token, access_token_expires=@access_token_expires, access_token_lastat=@access_token_lastat where id=@id");
        myDaoAccessTokenStore.setParams(params);
        WxApi2Impl wxApi2 = new WxApi2Impl();
        wxApi2.setAppid(appInfo.getAppid());
        wxApi2.setAppsecret(appInfo.getAppsecret());
        wxApi2.setEncodingAesKey(appInfo.getEncodingAESKey());
        wxApi2.setToken(appInfo.getToken());
        wxApi2.setAccessTokenStore(myDaoAccessTokenStore);
        return wxApi2;
    }
2017三月17

log4j 换成 logback 注意事项

pom.xml

 

<dependency>  
    <groupId>ch.qos.logback</groupId>  
    <artifactId>logback-classic</artifactId>  
    <version>1.2.2</version>  
</dependency>  
<dependency>  
    <groupId>org.logback-extensions</groupId>  
    <artifactId>logback-ext-spring</artifactId>  
    <version>0.1.4</version>  
</dependency>  
<dependency>  
    <groupId>org.slf4j</groupId>  
    <artifactId>jcl-over-slf4j</artifactId>  
    <version>1.7.25</version>  
</dependency>
<dependency>  
    <groupId>org.slf4j</groupId>  
    <artifactId>log4j-over-slf4j</artifactId>  
    <version>1.7.25</version>  
</dependency>

 

排除其他包的log4j引用,特别是dubbo的、shiro的

 

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>dubbo</artifactId>
            <version>2.8.4</version>
            <exclusions>
                <exclusion>
                    <groupId>log4j</groupId>
                    <artifactId>log4j</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>javax.ws.rs</groupId>
            <artifactId>javax.ws.rs-api</artifactId>
            <version>2.0</version>
            <exclusions>
                <exclusion>
                    <groupId>log4j</groupId>
                    <artifactId>log4j</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.apache.shiro</groupId>
            <artifactId>shiro-ehcache</artifactId>
            <version>1.3.2</version>
            <exclusions>
                <exclusion>
                    <groupId>log4j</groupId>
                    <artifactId>log4j</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.apache.shiro</groupId>
            <artifactId>shiro-web</artifactId>
            <version>1.3.2</version>
            <exclusions>
                <exclusion>
                    <groupId>log4j</groupId>
                    <artifactId>log4j</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

配置文件:

<?xml version="1.0" encoding="UTF-8"?>

<!-- For assistance related to logback-translator or configuration  -->
<!-- files in general, please contact the logback user mailing list -->
<!-- at http://www.qos.ch/mailman/listinfo/logback-user             -->
<!--                                                                -->
<!-- For professional support please see                            -->
<!--    http://www.qos.ch/shop/products/professionalSupport         -->
<!--                                                                -->
<configuration>
    <appender name="Console" class="ch.qos.logback.core.ConsoleAppender">
        <file>/monitor.log</file>

        <!-- Policy定义如何滚动,按文件大小滚动生成日志 -->
        <!-- 如果是按文件大小滚动生成日志,前面的file标签可省略,而使用fileNamePattern标签定义的名字 -->
        <rollingPolicy class="ch.qos.logback.core.rolling.FixedWindowRollingPolicy">
            <fileNamePattern>/monitor.%i.log.gz
            </fileNamePattern>
            <!-- 归档日志的下标,替换fileNamePattern的%i,最多3个归档文件 -->
            <minIndex>1</minIndex>
            <maxIndex>5</maxIndex>
        </rollingPolicy>

        <!-- triggeringPolicy定义什么时候滚动,下面是定义了文件大小超过100M的时候产生归档文件 -->
        <triggeringPolicy
                class="ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy">
            <maxFileSize>300MB</maxFileSize>
        </triggeringPolicy>

        <!-- append是否接着上次写文件结尾继续写,默认为true -->
        <append>true</append>
        <encoding>GBK</encoding>

        <!-- layout,定义格式 -->
        <layout class="ch.qos.logback.classic.PatternLayout">
            <pattern>[%-5level] %d{HH:mm:ss.SSS} [%thread] %logger %caller{2} - %msg%n</pattern>
        </layout>
    </appender>
    <logger name="org.springframework" level="info"/>
    <logger name="org.nutz.dao" level="debug"/>
    <logger name="net.sf.ehcache" level="info"/>
    <logger name="druid.sql" level="info"/>
    <logger name="com.alibaba.druid" level="info"/>
    <logger name="org.apache.shiro" level="info"/>
    <logger name="org.quartz" level="info"/>
    <root level="debug">
        <appender-ref ref="Console"/>
    </root>
</configuration>
2016十二月8

Nutz:组合查询、子查询示例代码

        Cnd cnd = Cnd.NEW();
        if (!Strings.isBlank(src)) {
            cnd.and("srcFrom", "=", src);
        }
        if (!Strings.isBlank(name)) {
            String[] n = StringUtils.split(name, " ");
            SqlExpressionGroup group = new SqlExpressionGroup();
            for (String s : n) {
                SqlExpression sqlExpression = Cnd.exp("srcName", "like", "%" + s + "%");
                group.or(sqlExpression);
            }
            cnd.and(group);
        }
        cnd.and(Cnd.exps("productSku", "=", "").or("productSku", "is", null));
2016十一月28

Elasticsearch 5.0 以上 elasticsearch-head 安装教程

elasticsearch 5.0/5.0.1以上版本的elasticsearch-head插件,使用node单独运行,会出现跨站访问的问题:

http://localhost:9200/_nodes. No 'Access-Control-Allow-Origin' 
header is present on the requested resource. 
Origin 'http://localhost:9100' is therefore not allowed access.

elasticsearch-head 安装教程如下:

1、安装node;
2、下载elasticsearch-head,安装node组件:

>git clone git://github.com/mobz/elasticsearch-head.git
>cd elasticsearch-head
>npm i
>npm i grunt-cli -g
>grunt server

3、elasticsearch.yml 增加配置项

http.cors.enabled: true
http.cors.allow-origin: /http?:\/\/127.0.0.1(:[0-9]+)?/

4、Gruntfile.js 增加hostname配置项

connect: {
         server: {
            options: {
               port: 9100,
               hostname: '*',
               base: '.',
               keepalive: true
            }
         }
      }

5、修改配置文件后各自重启

http://localhost:9100/ 访问即可

2016十月20

Nutz:fetchLinks 三级关联表的应用

        Shop_goods_type obj = shopGoodsTypeService.fetch(id);
        shopGoodsTypeService.fetchLinks(obj, null, Cnd.orderBy().asc("location"));
        for (Shop_goods_type_props o : obj.getPropsList()) {
            shopGoodsTypeService.dao().fetchLinks(o, null, Cnd.orderBy().asc("location"));
        }
2016九月12

VUE: htmlWebpackPlugin is not defined 解决办法

webpack.base.conf.js

vue-html 注释掉

// {
//   test: /\.html$/,
//   loader: 'vue-html'
// },

2016八月19

Nginx:绑定域名代理tomcat

server {
	listen 80;
	listen 443 ssl;
	if ( $scheme = "http" ) {
            rewrite ^(.*) https://$host$1;
	}
	server_name nutzwk.wizzer.cn;
	root "/java/work/nutzwk";	
	ssl_certificate /java/work/1_nutzwk.wizzer.cn_bundle.crt;
	ssl_certificate_key /java/work/2_nutzwk.wizzer.cn.key;
	add_header "X-UA-Compatible" "IE=Edge, chrome=1";
	location / {
		proxy_pass http://127.0.0.1:9091;
		proxy_set_header Host $host;
		proxy_set_header X-Real-IP $remote_addr;
		proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
	}
}