freemarker简单案例

小灰灰 2022-05-12 10:16 202阅读 0赞

*  一、环境说明：win10专业版、jdk1.8.0\_171、eclipse4.7.3a、Junit5
 *  ![70][]
 *  二、步骤说明：
 *  1.创建一个简单的maven工程freemarker
 *  2.引入pom依赖，pom文件具体如下：

<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">
      <modelVersion>4.0.0</modelVersion>
      <groupId>com.szcatic</groupId>
      <artifactId>freemarker</artifactId>
      <version>0.0.1-SNAPSHOT</version>
      <dependencies>
      	
    	<dependency>
    	    <groupId>org.junit.jupiter</groupId>
    	    <artifactId>junit-jupiter-engine</artifactId>
    	    <version>5.2.0</version>
    	    <scope>test</scope>
    	</dependency>
    	<dependency>
    	    <groupId>org.junit.platform</groupId>
    	    <artifactId>junit-platform-runner</artifactId>
    	    <version>1.2.0</version>
    	    <scope>test</scope>
    	</dependency>
      	<dependency>
    	    <groupId>org.freemarker</groupId>
    	    <artifactId>freemarker</artifactId>
    	    <version>2.3.28</version>
    	</dependency>
      </dependencies>
    </project>

*  3.编写工具类
    
        package com.szcatic.util;
        
        import java.io.File;
        import java.io.FileOutputStream;
        import java.io.IOException;
        import java.io.OutputStream;
        import java.io.OutputStreamWriter;
        import java.io.Writer;
        import java.util.HashMap;
        import java.util.Map;
        
        import com.szcatic.entity.Model;
        
        import freemarker.template.Configuration;
        import freemarker.template.Template;
        import freemarker.template.TemplateException;
        import freemarker.template.TemplateExceptionHandler;
        
        /**
         * 代码生成器工具类
         * @author zsx
         * @version 2018-09-17
         *
         */
        public class CodeGeneratorUtils {
        
        	/**
        	 * 
        	 * @param templatePath 模板路径
        	 * @param templateName 模板名称
        	 * @param filePath 生成文件的路径
        	 * @param fileName 生成文件的名称
        	 * @param model 生成模型
        	 */
        	public static void genCode(String templatePath, String templateName, String filePath, String fileName,
        			Map<String, Object> model) {
        		OutputStream os = null;
        		try {
        			Configuration cfg = new Configuration(Configuration.VERSION_2_3_22);
        			cfg.setDirectoryForTemplateLoading(new File(templatePath));
        			cfg.setDefaultEncoding("UTF-8");
        			cfg.setTemplateExceptionHandler(TemplateExceptionHandler.RETHROW_HANDLER);
        			Template temp = cfg.getTemplate(templateName);
        			File dir = new File(filePath);
        			if(!dir.exists()) {
        				dir.mkdirs();
        			}
        			os = new FileOutputStream(new File(dir, fileName));    
        			Writer out = new OutputStreamWriter(os);
        			temp.process(model, out);
        			System.out.println("gen code success!");
        			os.flush();
        		} catch (IOException e) {
        			e.printStackTrace();
        		} catch (TemplateException e) {
        			e.printStackTrace();
        		}finally {
        			if (os != null) {
        				try {
        					os.close();
        				} catch (IOException e) {
        					e.printStackTrace();
        				}
        			}
        		}   
        	}
        	
        	/**
        	 * 获取模型数据
        	 * @param model
        	 * @return
        	 */
        	public static Map<String, Object> getModel(Model model) {
        		Map<String, Object> map = new HashMap<String, Object>();
        		map.put("model", model);
        		return map;
        	}
        	
        }

*  4.创建模型实体类
    
        package com.szcatic.entity;
        
        import java.io.Serializable;
        import java.util.List;
        
        /**
         * 模板实体类
         * 
         * @author zsx
         * @version 2018-09-17
         *
         */
        public class Model implements Serializable {
        
        	private static final long serialVersionUID = 1L;
        
        	private String packageName; // 包名
        	private String author; // 作者
        	private String version; // 版本号
        	private String className; // 类名
        	private String classDescription; // 类描述
        	private List<ClassAttribute> classAttributes; // 类属性列表
        	
        	public Model() {
        		super();
        	}
        
        	public Model(String packageName, String author, String version, String className, String classDescription,
        			List<ClassAttribute> classAttributes) {
        		super();
        		this.packageName = packageName;
        		this.author = author;
        		this.version = version;
        		this.className = className;
        		this.classDescription = classDescription;
        		this.classAttributes = classAttributes;
        	}
        	
        	public String getPackageName() {
        		return packageName;
        	}
        
        	public void setPackageName(String packageName) {
        		this.packageName = packageName;
        	}
        
        	public String getAuthor() {
        		return author;
        	}
        
        	public void setAuthor(String author) {
        		this.author = author;
        	}
        
        	public String getVersion() {
        		return version;
        	}
        
        	public void setVersion(String version) {
        		this.version = version;
        	}
        
        	public String getClassName() {
        		return className;
        	}
        
        	public void setClassName(String className) {
        		this.className = className;
        	}
        
        	public String getClassDescription() {
        		return classDescription;
        	}
        
        	public void setClassDescription(String classDescription) {
        		this.classDescription = classDescription;
        	}
        
        	public List<ClassAttribute> getClassAttributes() {
        		return classAttributes;
        	}
        
        	public void setClassAttributes(List<ClassAttribute> classAttributes) {
        		this.classAttributes = classAttributes;
        	}
        
        	@Override
        	public String toString() {
        		return "Model [packageName=" + packageName + ", author=" + author + ", version=" + version + ", className="
        				+ className + ", classDescription=" + classDescription + ", classAttributes=" + classAttributes + "]";
        	}
        
        }
    
     
 *  5.创建类属性实体类
    
        package com.szcatic.entity;
        
        import java.io.Serializable;
        
        /**
         * 类属性实体类
         * 
         * @author zsx
         * @version 2018-09-17
         *
         */
        public class ClassAttribute implements Serializable {
        
        	private static final long serialVersionUID = 1L;
        
        	private String attributeName; // 属性名
        	private String attributeType; // 属性类型
        	
        	public ClassAttribute() {
        		super();
        	}
        
        	public ClassAttribute(String attributeName, String attributeType) {
        		super();
        		this.attributeName = attributeName;
        		this.attributeType = attributeType;
        	}
        
        	public String getAttributeName() {
        		return attributeName;
        	}
        
        	public void setAttributeName(String attributeName) {
        		this.attributeName = attributeName;
        	}
        
        	public String getAttributeType() {
        		return attributeType;
        	}
        
        	public void setAttributeType(String attributeType) {
        		this.attributeType = attributeType;
        	}
        
        	@Override
        	public String toString() {
        		return "ClassAttribute [attributeName=" + attributeName + ", attributeType=" + attributeType + "]";
        	}
        
        }

*  6.编写模板文件，文件名为model.ftl
    
        package ${model.packageName};
        
        import java.io.Serializable;
        
        /**
         *  ${model.classDescription}
         *  @author ${model.author}
         *  @version ${model.version}
         */
        public class ${model.className} implements Serializable {
        
        	private static final long serialVersionUID = 1L;
        	
            <#list model.classAttributes as classAttribute> 
            private ${classAttribute.attributeType} ${classAttribute.attributeName};
            </#list>
        
            <#list model.classAttributes as classAttribute>
            public void set${classAttribute.attributeName?cap_first}(${classAttribute.attributeType} ${classAttribute.attributeName}){
                this.${classAttribute.attributeName} = ${classAttribute.attributeName};
            }
            public ${classAttribute.attributeType} get${classAttribute.attributeName?cap_first}(){
                return this.${classAttribute.attributeName};
            }
        
            </#list>
        }

*  7.编写测试类CodeGeneratorUtilsTest
    
        package com.szcatic.test;
        
        import java.util.ArrayList;
        import java.util.List;
        import java.util.Map;
        
        import org.junit.jupiter.api.Test;
        
        import com.szcatic.entity.ClassAttribute;
        import com.szcatic.entity.Model;
        import com.szcatic.util.CodeGeneratorUtils;
        
        public class CodeGeneratorUtilsTest {
        	
        	@Test
        	void testGenCode() {
        		String templatePath = ClassLoader.getSystemClassLoader().getResource("").getPath(); 
        		String templateName = "model.ftl";
        		String filePath = "src/main/java/com/szcatic/entity";
        		String fileName = "User.java";
        		List<ClassAttribute> classAttributes = new ArrayList<>();
        		ClassAttribute classAttribute = new ClassAttribute("id", "Long");
        		classAttributes.add(classAttribute);
        		ClassAttribute classAttribute2 = new ClassAttribute("name", "String");
        		classAttributes.add(classAttribute2);
        		ClassAttribute classAttribute3 = new ClassAttribute("age", "Integer");
        		classAttributes.add(classAttribute3);
        		Model model = new Model("com.szcatic.entity", "zsx", "2018-09-17", "User", "用户实体类", classAttributes);
        		Map<String, Object> map = CodeGeneratorUtils.getModel(model);
        		CodeGeneratorUtils.genCode(templatePath, templateName, filePath, fileName, map);
        	}
        }
    
    运行测试方法，控制台输出如下，表示生成文件成功
    
        gen code success!
    
     
 *  8.最后刷新项目，结构如下：
 *  ![70 1][]![70 2][]

[70]: /images/20220512/46babd85b3754d0a9473936f3956421d.png
[70 1]: https://img-blog.csdn.net/20180917132833136?watermark/2/text/aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3pzeDE4MjczMTE3MDAz/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70
[70 2]: /images/20220512/944b15a527b446b6a838fcc3790b4e3f.png