Guava学习笔记:List<E>转换(int->String)

本文展示了如何使用Google Guava库中的Function接口实现将整数列表转换为字符串列表的功能,包括输入验证和使用Lists.transform方法。

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method1:

package com.amg.test;

import java.util.List;
import com.google.common.base.Function;
import com.google.common.base.Preconditions;
import com.google.common.collect.Lists;

public class Integer2String {

	public static void main(String[] args) {
		Function function = new Function<Integer, String>() {
			@Override
			public String apply(Integer input) {
				Preconditions.checkArgument(null != input && !"".equals(input), "input is null!");
				return String.valueOf(input);
			}
		};
		List<Integer> fromList = Lists.newArrayList(111, 33, 222, 675432);
		List<String> to = Lists.transform(fromList, function);

		for (int i = 0; i < fromList.size(); i++) {
			System.out.println(to.get(i));
		}
	}

}

 

method2:

package com.amg.test;

import java.util.List;
import com.google.common.base.Function;
import com.google.common.base.Preconditions;
import com.google.common.collect.Lists;

public class Integer2String {

	public static void main(String[] args) {
		List<Integer> fromList = getIntList();
		List<String> to = transferInt2String(fromList);
		for (String str : to) {
			System.out.println(str);
		}
	}

	public static List<Integer> getIntList() {
		return Lists.newArrayList(111, 33, 222, 675432);
	}

	public static List<String> transferInt2String(List<Integer> fromList) {

		return Lists.transform(fromList, new Function<Integer, String>() {
			@Override
			public String apply(Integer input) {
				Preconditions.checkArgument(null != input && !"".equals(input),
						"input is null!");
				return String.valueOf(input);
			}
		});
	}

}

 运行结果:

111
33
222
675432

 

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <parent> <groupId>org.jeecgframework.boot</groupId> <artifactId>jeecg-module-system</artifactId> <version>3.4.0</version> </parent> <modelVersion>4.0.0</modelVersion> <artifactId>jeecg-system-biz</artifactId> <dependencies> <dependency> <groupId>org.jeecgframework.boot</groupId> <artifactId>jeecg-system-local-api</artifactId> <exclusions> <exclusion> <artifactId>checker-qual</artifactId> <groupId>org.checkerframework</groupId> </exclusion> <exclusion> <artifactId>guava</artifactId> <groupId>com.google.guava</groupId> </exclusion> <exclusion> <artifactId>mybatis-plus-extension</artifactId> <groupId>com.baomidou</groupId> </exclusion> <exclusion> <artifactId>swagger-annotations</artifactId> <groupId>io.swagger</groupId> </exclusion> </exclusions> </dependency> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-core</artifactId> </dependency> <dependency> <groupId>org.jeecgframework.boot</groupId> <artifactId>hibernate-re</artifactId> </dependency> <!-- 企业微信/钉钉 api --> <dependency> <groupId>org.jeecgframework</groupId> <artifactId>jeewx-api</artifactId> <exclusions> <exclusion> <artifactId>commons-collections</artifactId> <groupId>commons-collections</groupId> </exclusion> <exclusion> <artifactId>commons-logging</artifactId> <groupId>commons-logging</groupId> </exclusion> </exclusions> </dependency> <!-- 积木报表 --> <dependency> <groupId>org.jeecgframework.jimureport</groupId> <artifactId>jimureport-spring-boot-starter</artifactId> <exclusions> <exclusion> <artifactId>commons-collections</artifactId> <groupId>commons-collections</groupId> </exclusion> <exclusion> <artifactId>commons-logging</artifactId> <groupId>commons-logging</groupId> </exclusion> </exclusions> </dependency> <!-- manage --> <dependency> <groupId>com.baomidou</groupId> <artifactId>mybatis-plus-extension</artifactId> <version>3.5.1</version> <exclusions> <exclusion> <artifactId>jsqlparser</artifactId> <groupId>com.github.jsqlparser</groupId> </exclusion> </exclusions> </dependency> <dependency> <groupId>io.swagger</groupId> <artifactId>swagger-annotations</artifactId> <version>1.5.22</version> </dependency> <dependency> <groupId>net.sf.dozer</groupId> <artifactId>dozer</artifactId> <version>5.5.1</version> <exclusions> <exclusion> <artifactId>commons-beanutils</artifactId> <groupId>commons-beanutils</groupId> </exclusion> </exclusions> </dependency> <dependency> <groupId>com.baidu.aip</groupId> <artifactId>java-sdk</artifactId> <version>4.16.2</version> <exclusions> <exclusion> <artifactId>guava</artifactId> <groupId>com.google.guava</groupId> </exclusion> <exclusion> <artifactId>jsr305</artifactId> <groupId>com.google.code.findbugs</groupId> </exclusion> <exclusion> <artifactId>slf4j-simple</artifactId> <groupId>org.slf4j</groupId> </exclusion> </exclusions> </dependency> <dependency> <groupId>net.sourceforge.tess4j</groupId> <artifactId>tess4j</artifactId> <version>3.4.0</version> <exclusions> <exclusion> <artifactId>commons-beanutils</artifactId> <groupId>commons-beanutils</groupId> </exclusion> <exclusion> <artifactId>commons-io</artifactId> <groupId>commons-io</groupId> </exclusion> <exclusion> <artifactId>commons-logging</artifactId> <groupId>commons-logging</groupId> </exclusion> </exclusions> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-configuration-processor</artifactId> <optional>true</optional> </dependency> <dependency> <groupId>org.apache.poi</groupId> <artifactId>poi-ooxml</artifactId> <version>4.1.2</version> </dependency> <dependency> <groupId>commons-net</groupId> <artifactId>commons-net</artifactId> <version>3.6</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> <version>5.2.7.RELEASE</version> </dependency> <!-- /manage --> <!--PDF--> <dependency> <groupId>com.lowagie</groupId> <artifactId>itext</artifactId> <version>2.1.7</version> </dependency> <dependency> <groupId>org.opencv</groupId> <artifactId>opencv</artifactId> <version>4.6.0</version> <scope>system</scope> <systemPath>${project.basedir}/src/main/resources/lib/opencv-460.jar</systemPath> </dependency> <!--ocr引用--> <!-- https://mvnrepository.com/artifact/com.google.code.gson/gson --> <dependency> <groupId>com.google.code.gson</groupId> <artifactId>gson</artifactId> <version>2.8.9</version> </dependency> <!--识别中文拼音首字母--> <dependency> <groupId>com.belerweb</groupId> <artifactId>pinyin4j</artifactId> <version>2.5.1</version> </dependency> <!-- PDFBox --> <dependency> <groupId>org.apache.pdfbox</groupId> <artifactId>pdfbox</artifactId> <version>2.0.24</version> </dependency> <!-- iText --> <dependency> <groupId>com.itextpdf</groupId> <artifactId>itext7-core</artifactId> <version>7.1.15</version> <type>pom</type> </dependency> <dependency> <groupId>org.bytedeco</groupId> <artifactId>javacv-platform</artifactId> <version>1.4.3</version> </dependency> <dependency> <groupId>javax.media</groupId> <artifactId>jai-core</artifactId> <version>1.1.3</version> </dependency> <!--导入easyexcel--> <dependency> <groupId>com.alibaba</groupId> <artifactId>easyexcel</artifactId> <version>3.2.1</version> </dependency> <dependency> <groupId>jakarta.servlet</groupId> <artifactId>jakarta.servlet-api</artifactId> <version>4.0.4</version> <scope>provided</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-configuration-processor</artifactId> <version>2.7.9</version> <optional>true</optional> </dependency> <!-- EXIF 元数据提取 --> <dependency> <groupId>com.drewnoakes</groupId> <artifactId>metadata-extractor</artifactId> <version>2.16.0</version> </dependency> <!-- OFD 文件处理 --> <dependency> <groupId>org.ofdrw</groupId> <artifactId>ofdrw-full</artifactId> <version>2.3.6</version> </dependency> </dependencies> <!-- <build>--> <!-- <resources>--> <!-- <resource>--> <!-- <directory>src/main/resources</directory>--> <!-- <excludes>--> <!-- <exclude>**/*.class</exclude>--> <!-- </excludes>--> <!-- </resource>--> <!-- <resource>--> <!-- <directory>src/main/resources/libs</directory>--> <!-- <includes>--> <!-- <include>**/*.jar</include>--> <!-- </includes>--> <!-- </resource>--> <!-- </resources>--> <!-- </build>--> </project> 这是我的pom.xml,使用这个引用编写一份把PDF转换成ofd,包括PDF的标签, OFD ofd = ofdDoc.getOfd();这个方法,找不到方法调用 ofdDoc.getOfd() 的候选者 import org.ofdrw.core.basicStructure.doc.Bookmark; import org.ofdrw.core.basicStructure.doc.Bookmarks; 这两个标签无法引用 Page ofdPage = new Page(); ofdPage.setSize(getPageSize(pdfDoc.getPage(i))); ST_ID pageId = ofdDoc.addPage(ofdPage); 找不到方法调用 ofdDoc.addPage(ofdPage) ,ofdDoc.addPage(ofdPage);的候选者。 无法解析符号 'Bookmarks'
最新发布
07-03
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