使用Java Stream多次处理结果

Question

How do I convert to Java Stream the for-loop part in the following codes? 如何在以下代码中将for-loop部分转换为Java Stream？

    Map<String, String> attributes = new HashMap() {{
        put("header", "Hello, world!");
        put("font", "Courier New");
        put("fontSize", "14px");
        put("color", "#0000ff");
        put("content", "hello, world" +
                "");
    }};
    Path templatePath = Paths.get("C:/workspace/spring-boot-demos/something.tpl");
List<String> lines = Files.readAllLines(templatePath).stream()
                .filter(Objects::nonNull)
                .map(line -> {
                    String parsedLine = "";
                    for (int i = 0; i < attributes.size(); i++) {
                        if (parsedLine.equals("")) parsedLine = this.parse(attributes, line);
                        else parsedLine = this.parse(attributes, parsedLine);
                    }

                    return parsedLine;
                })
                .collect(Collectors.toList());

public String parse(Map<String, String> attributes, String line) {
        return attributes.entrySet().stream()
                .filter(attributeMap -> line.indexOf("{{" + attributeMap.getKey() + "}}") != -1)
                .map(attributeMap -> {
                    String attributeKey = attributeMap.getKey();
                    String attributeValue = attributeMap.getValue();
                    String newLine = line.replace("{{" + attributeKey + "}}", attributeValue);
                    return newLine;
                })
                .findFirst().orElse(line);
    }

I find it difficult to implement it in Java 8 Stream way so that I'm forced to do it old for-loop construct. 我发现很难以Java 8 Stream方式实现它，因此我不得不执行旧的for-loop构造。 The reason behind this is that for every line of string, there might one or more placeholder (using {{}} delimiter). 其背后的原因是，对于字符串的每一行，可能会有一个或多个占位符（使用{{}}分隔符）。 I have the list ( attributes , HashMap ) of the value to replace them. 我有值列表（ attributes ， HashMap ）来替换它们。 I want to make sure that before the loop of Stream leave every line, all of the placeholders must replaced with the value from the Map . 我想确保在Stream循环离开每一行之前，所有占位符都必须替换为Map的值。 Without doing this, only the first placeholder is being replaced. 无需执行此操作，仅替换第一个占位符。

Thank you. 谢谢。

Update: This is the content of something.tpl file: 更新：这是something.tpl文件的内容：

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="utf-8">
        <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
        <title>HTML Generator</title>
        <style>
            body {
                font-family: "{{font}}";
                font-size: {{fontSize}};
                color: {{color}};
            }
        </style>
    </head>
    <body>
        <header>{{header}}</header> {{content}}
        <main>{{content}}</main>
        <h1>{{header}}</h1>
    </body>
</html>

Answer 1

So you want to replace every token in the given List ? 因此，您要替换给定列表中的每个标记吗？

Here's how I would do it with streams : 这是我对流进行的操作：

Iterate over lines 遍历行
parse each line only once 每行仅解析一次
the parsing iterates over attributes, and replaces the current attribute 解析遍历属性，并替换当前属性

The String[] pLine may be was you were missing... 如果您丢失了String[] pLine可能是...

package so20190412;

import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

public class Snippet {

    public Snippet() {
    }

    public static void main(String[] args) {        

        Map<String, String> attributes = new HashMap<String, String> () {{
            put("john", "doe");
            put("bruce", "wayne");
        }};
        List<String> lines = Arrays.asList("My name is {{john}}, not {{bruce}}.", "Hello, {{john}}!", "How are you doing?");

        new Snippet().replaceAll(attributes, lines).forEach(System.out::println);

    }

    public List<String> replaceAll(Map<String, String> attributes, List<String> lines) {
        return lines.stream().map(l -> parse(attributes, l)).collect(Collectors.toList());
    }

    public String parse(Map<String, String> attributes, String line) {
        String[] pLine = {line};
        attributes.entrySet().stream()
                .forEach(attr -> {
                    String attributeKey = attr.getKey();
                    String attributeValue = attr.getValue();
                    String newLine = pLine[0].replace("{{" + attributeKey + "}}", attributeValue);
                    pLine[0] = newLine;
                });
        return pLine[0];
    }
}

Don't hesitate to ask if you don't understand some part. 不要犹豫，问一下您是否不了解某些内容。

HTH! HTH！

使用Java Stream多次处理结果

问题描述

1 个解决方案

解决方案1
2 已采纳 2019-04-12 07:05:47

使用Java Stream多次处理结果

问题描述

1 个解决方案

解决方案1 2 已采纳 2019-04-12 07:05:47

解决方案1
2 已采纳 2019-04-12 07:05:47