使用javax.json.JsonObject作为数据模型的FreeMarker

我正在测试FreeMarker

Maven依赖项：

<dependencies>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.glassfish</groupId>
        <artifactId>javax.json</artifactId>
        <version>1.0.4</version>
        <scope>test</scope>
    </dependency>

    <dependency>
        <groupId>org.freemarker</groupId>
        <artifactId>freemarker</artifactId>
        <version>2.3.23</version>
    </dependency>
</dependencies>

简单自由标记文件（basicJson.ftl）：

用于创建配置的类：

public class User {

    private String firstName;
    private String lastName;
    private String email;

    public User(String firstName, String lastName, String email) {
        this.firstName = firstName;
        this.lastName = lastName;
        this.email = email;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

}

Name: ${user.firstName} ${user.lastName}

import java.io.File;
import java.io.IOException;

import freemarker.template.Configuration;
import freemarker.template.TemplateExceptionHandler;

public class FreemarkerConfigurationFactory {

    public static Configuration newFreemarkerConfiguration() throws IOException {
        Configuration cfg = new Configuration(Configuration.VERSION_2_3_23);
        cfg.setDirectoryForTemplateLoading(new File("./templates/tests/"));
        cfg.setDefaultEncoding("UTF-8");
        cfg.setTemplateExceptionHandler(TemplateExceptionHandler.RETHROW_HANDLER);
        cfg.setLogTemplateExceptions(false);
        return cfg;
    }

}

测试等级：

import static org.junit.Assert.assertEquals;

import java.io.ByteArrayOutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.HashMap;
import java.util.Map;

import javax.json.Json;
import javax.json.JsonObject;

import org.junit.Before;
import org.junit.Test;

import freemarker.template.Configuration;
import freemarker.template.Template;

public class FreemarkerJsonTest {

    private Configuration cfg;
    private ByteArrayOutputStream output;
    private Template template;
    private Writer writer;
    private Map<String, Object> map;

    @Before
    public void setUp() throws Exception {
        cfg =  FreemarkerConfigurationFactory.newFreemarkerConfiguration();
        output = new ByteArrayOutputStream();
        writer = new OutputStreamWriter(output);
        map = new HashMap<>();
    }

    @Test
    public void objectTest() throws Exception {
        User user = new User("Clarice", "Leman", "clarice.leman@domain.com");
        map.put("user", user);
        String outputString = process("basicJson.ftl", map);
        assertEquals("Name: Clarice Leman", outputString);
    }

    @Test
    public void jsonTest() throws Exception {
        JsonObject jsonUser = Json.createObjectBuilder()
            .add("id", 10)
            .add("firstName", "Clarice")
            .add("lastName", "Leman")
            .add("email", "clarice.leman@domain.com")
            .build();

        map.put("user", jsonUser);
        String outputString = process("basicJson.ftl", map);
        assertEquals("Name: Clarice Leman", outputString);
    }

    private String process(String templateName, Object root) throws Exception {
        template = cfg.getTemplate(templateName);
        template.process(root, writer);
        return output.toString();
    }

}

使用在线FreeMarker模板（）：

模板：

Name: ${user.firstName} ${user.lastName}

user = {"firstName":"Clarice","lastName":"Leman","email":"clarice.leman@domain.com"}

数据模型：

Name: ${user.firstName} ${user.lastName}

user = {"firstName":"Clarice","lastName":"Leman","email":"clarice.leman@domain.com"}

结果

Name: Clarice Leman

---

您在FreeMarker Online上输入的JSON在传递给FreeMarker本身之前，会被FreeMarker Online转换为

列表

-s和

映射

-s。整个框的语法特定于该在线服务。因此，如果要显示JSON，则必须将其转换为FreeMarker的默认

ObjectWrapper

已经理解的内容，或者必须扩展

ObjectWrapper

以理解

javax.JSON

类。（但通常情况下，您会将JSON绑定到一些特定于应用程序的类，而这些类通常已经使用JavaBeans约定和默认的

ObjectWrapper

理解的

列表），感谢您的回答。我认为FreeMarker已经处理了javax.json类，因为输出显示了预期的值，除了字符串值被引用。您肯定看到了这些对象的
toString（）
返回值。FreeMarker的默认
ObjectWrapper
将包装它不理解的对象，以便它们可以用作字符串，并且通过调用
toString（）
计算字符串值。