使用PhantomJS在服务器端渲染并生成Echarts图片

Posted 2020-11-19

1，使用的jar包

<dependency>
     <groupId>org.apache.commons</groupId>
   <artifactId>commons-exec</artifactId>
   <version>1.3</version>
</dependency>
<dependency>
    <groupId>com.github.abel533</groupId>
    <artifactId>ECharts</artifactId>
    <version>3.0.0.2</version>
</dependency>
<dependency>
    <groupId>com.google.code.gson</groupId>
    <artifactId>gson</artifactId>
</dependency>
<dependency>
    <groupId>com.github.abel533</groupId>
    <artifactId>ECharts</artifactId>
    <version>3.0.0.2</version>
</dependency>

,2，创建要用的js（echarts-convert.js）

function Base64() {
    // private property
    _keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
    // public method for encoding
    this.encode = function (input) {
        var output = "";
        var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
        var i = 0;
        input = _utf8_encode(input);
        while (i < input.length) {
            chr1 = input.charCodeAt(i++);
            chr2 = input.charCodeAt(i++);
            chr3 = input.charCodeAt(i++);
            enc1 = chr1 >> 2;
            enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
            enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
            enc4 = chr3 & 63;
            if (isNaN(chr2)) {
                enc3 = enc4 = 64;
            } else if (isNaN(chr3)) {
                enc4 = 64;
            }
            output = output +
            _keyStr.charAt(enc1) + _keyStr.charAt(enc2) +
            _keyStr.charAt(enc3) + _keyStr.charAt(enc4);
        }
        return output;
    }

    // public method for decoding
    this.decode = function (input) {
        var output = "";
        var chr1, chr2, chr3;
        var enc1, enc2, enc3, enc4;
        var i = 0;
        input = input.replace(/[^A-Za-z0-9+/=]/g, "");
        while (i < input.length) {
            enc1 = _keyStr.indexOf(input.charAt(i++));
            enc2 = _keyStr.indexOf(input.charAt(i++));
            enc3 = _keyStr.indexOf(input.charAt(i++));
            enc4 = _keyStr.indexOf(input.charAt(i++));
            chr1 = (enc1 << 2) | (enc2 >> 4);
            chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
            chr3 = ((enc3 & 3) << 6) | enc4;
            output = output + String.fromCharCode(chr1);
            if (enc3 != 64) {
                output = output + String.fromCharCode(chr2);
            }
            if (enc4 != 64) {
                output = output + String.fromCharCode(chr3);
            }
        }
        output = _utf8_decode(output);
        return output;
    }

    // private method for UTF-8 encoding
    _utf8_encode = function (string) {
        string = string.replace(/
/g,"
");
        var utftext = "";
        for (var n = 0; n < string.length; n++) {
            var c = string.charCodeAt(n);
            if (c < 128) {
                utftext += String.fromCharCode(c);
            } else if((c > 127) && (c < 2048)) {
                utftext += String.fromCharCode((c >> 6) | 192);
                utftext += String.fromCharCode((c & 63) | 128);
            } else {
                utftext += String.fromCharCode((c >> 12) | 224);
                utftext += String.fromCharCode(((c >> 6) & 63) | 128);
                utftext += String.fromCharCode((c & 63) | 128);
            }
        }
        return utftext;
    }

    // private method for UTF-8 decoding
    _utf8_decode = function (utftext) {
        var string = "";
        var i = 0;
        var c = c1 = c2 = 0;
        while ( i < utftext.length ) {
            c = utftext.charCodeAt(i);
            if (c < 128) {
                string += String.fromCharCode(c);
                i++;
            } else if((c > 191) && (c < 224)) {
                c2 = utftext.charCodeAt(i+1);
                string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
                i += 2;
            } else {
                c2 = utftext.charCodeAt(i+1);
                c3 = utftext.charCodeAt(i+2);
                string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
                i += 3;
            }
        }
        return string;
    }
}

///////////////////////////////////
system = require(‘system‘); // 获取参数
var jspath = system.args[0];
var base64JsonStr = system.args[1];
//将base64解密
var paramsJsonStr =  new Base64().decode(base64JsonStr) ;
//转换为json对象
var jsonObj = JSON.parse(paramsJsonStr);

var option = jsonObj.opt ;
var width = jsonObj.width ;
var height = jsonObj.height ;
var outfile = jsonObj.outfile ;
var fileSuffix = jsonObj.type ;

function Convert(params){
    this.params = params ;
    this.external = {
        JQUERY3 :  ‘jquery-1.9.1.min.js‘,
        ECHARTS3 : ‘echarts3.8.5.min.js‘
    }; // 外部js
    this.page = require(‘webpage‘).create(); // 客户端
    this.page.onConsoleMessage = function(msg, lineNum, sourceId) {
        console.log(‘----console----‘+msg);
    };
    var instance = this ;
    this.page.onError = function(msg, trace) {
        var msgStack = [‘PHANTOM ERROR: ‘ + msg];
        if (trace && trace.length) {
             msgStack.push(‘TRACE:‘);
             trace.forEach(function(t) {
               msgStack.push(‘ -> ‘ + (t.file || t.sourceURL) + ‘: ‘ + t.line + (t.function ? ‘ (in function ‘ + t.function +‘)‘ : ‘‘));
             });
         }
        console.error(msgStack.join(‘
‘));
        instance.output("", false, msg); // 失败,返回错误信息
    };
}
Convert.prototype.init = function(){
    var instance = this ;
    instance.page.open("about:blank", function(status) {
        // 注入依赖js包
        var hasJquery = instance.page.injectJs(instance.external.JQUERY3);
        var hasEchart = instance.page.injectJs(instance.external.ECHARTS3);
        // 检查js是否引用成功
        if (!hasJquery || !hasEchart) {
            output("Could not found " + external.JQUERY3 + " or " + external.ECHARTS3, false);
        }
        // 创建echarts
        instance.page.evaluate(instance.createEchartsDom, instance.params);
        // 定义剪切范围，如果定义则截取全屏
        instance.page.clipRect = {
            top : 0,
            left : 0,
            width : instance.params.width,
            height : instance.params.height
        };
        // 渲染
        var result = instance.render();
        // 成功输出，返回图片或其他信息
        instance.output(result, true);
    });

}
Convert.prototype.render = function(){
    var instance = this ;
    switch (instance.params.type) {
    case ‘file‘:
        // 渲染图片
        instance.page.render(instance.params.outfile);
        return instance.params.outfile;
    case ‘base64‘:
    default:
        var base64 = instance.page.renderBase64(‘PNG‘);
        return base64;
    }
}
Convert.prototype.output = function(content, success, msg) {
    var instance = this ;
    console.log(success ? "[SUCCESS]:" : "[ERROR]:" + content);
    instance.page.close();
    instance.exit(instance.params); // exit
};
Convert.prototype.exit = function (params) {
    phantom.exit();
};

//
 // 创建eCharts Dom层
 // @param params 参数
 //         params.opt
 //     params.width    
 //     params.height
 //     params.outfile
 //     params.type = ‘PNG‘
 //
Convert.prototype.createEchartsDom = function(params) {
    console.log("---createEchartsDom--"+params.width) ;
    var instance = this ;
    options =  params.opt ;
    // 动态加载js，获取options数据
    $(‘<script>‘)
        .attr(‘type‘, ‘text/javascript‘) // .html(‘var options = ‘ + params.opt)
        .appendTo(document.head);
    // 取消动画,否则生成图片过快，会出现无数据
    if (options !== undefined) {
        options.animation = false;
    }
    // body背景设置为白色
    $(document.body).css(‘backgroundColor‘, ‘white‘);
    // echarts容器
    var container = $("<div>")
        .attr(‘id‘, ‘container‘)
        .css({
            width : params.width,
            height : params.height
        }).appendTo(document.body);

    var eChart = echarts.init(container[0]);
    eChart.setOption(options);
}

//构建,入口
new Convert(jsonObj).init();

3，Java代码

public class ImageRenderParams {
    //echart的Option
    public Option opt;
    //echart图片的宽度
    public int width = 600;
    //echart图片的高度
    public int height = 400;
    //echart图片保存地址
    public String outfile = "d:/dsafdf.png";
    //file 或者  PNG
    public String type = "file";
}
/**
     * 创建Echart图
     *
     * @param imagePath 图片保存地址，例如：d:/demo.png
     * @throws Exception
     */
    public ImageResult createEchartImage(Option option) throws Exception {
        if (option == null) {
            return new ImageResult();
        }
        String imgPath = getRandomImagePath(option);
        ImageRenderParams params = new ImageRenderParams();
        params.opt = option;
        params.outfile = imgPath;
        // 实例化
        Gson gson = new Gson();
        // 将map转成JSON
        String paramsJsonStr = gson.toJson(params);
        Base64 base64 = new Base64();
        //转换为base64编码是为了防止执行指令的时候出问题
        String base64Str = base64.encodeToString(paramsJsonStr.getBytes("UTF-8"));
        //调用的JS文件路径
        File jsFile = ResourceUtils.getFile("classpath:static/js/echarts-convert.js");
        // 生成的图片名称
        String jsFilePath = jsFile.getAbsolutePath();
        String[] args = new String[3];
        args[0] = jsFilePath;
        args[1] = base64Str;
        // 执行脚本
        try {
            CommandExecUtil.phantomjsExec(args);
        } catch (Exception e) {
            throw e;
        }
        return new ImageResult(imgPath);
    }

    public static class ImageResult {
        private String imagePath;
        private byte[] imageData;

        public ImageResult(String imagePath) {
            this.imagePath = imagePath;
        }

        public ImageResult() {
        }

        public String getImagePath() {
            return imagePath;
        }

        public byte[] getImageData() throws Exception {
            if (StringUtils.isBlank(imagePath)) {
                return null;
            }
            if (imageData != null) {
                return imageData;
            }
            File file = ResourceUtils.getFile(imagePath);
            if (file == null) {
                return null;
            }
            FileInputStream fi = new FileInputStream(file);
            imageData = new byte[fi.available()];
            fi.read(imageData);
            fi.close();
            return imageData;
        }
    }