0

如何将 java.util.Map 映射到 POJO？

以下测试给了我一个配置错误。

似乎打开了一个类似的问题，但没有解决https://github.com/jhalterman/modelmapper/issues/116。

测试：

package org.me.modelmapper;

import java.util.HashMap;
import org.modelmapper.ModelMapper;
import org.modelmapper.PropertyMap;
import org.testng.Assert;
import org.testng.annotations.BeforeMethod;
import org.testng.annotations.Test;

public class MapperTest {


    private ModelMapper modelMapper;


    public MapperTest() {
    }


    public static class Foo {

        public String a;
        public String b;

        public String getA() {
            return a;
        }

        public void setA(String a) {
            this.a = a;
        }

        public String getB() {
            return b;
        }

        public void setB(String b) {
            this.b = b;
        }

    }


    @BeforeMethod
    public void setUpMethod() throws Exception {
        modelMapper = new ModelMapper();
        modelMapper.getConfiguration()
                .setFieldMatchingEnabled(true);
    }

    @Test
    public void shouldMapHashMapToFoo() {
        HashMap<String, String> map = new HashMap<>();
        map.put("a", "aaaa");
        map.put("b", "bbbb");

        PropertyMap<HashMap<String, String>, Foo> fooMap = new PropertyMap<HashMap<String, String>, MapperTest.Foo>() {

            @Override
            protected void configure() {
                map(source.get("a"), destination.a);
                map(source.get("b"), destination.b);
            }

        };

        modelMapper.addMappings(fooMap);

        Foo foo = modelMapper.map(map, Foo.class);

        Assert.assertEquals(foo.getA(), map.get("a"));
        Assert.assertEquals(foo.getB(), map.get("b"));

    }

}

错误：

Configuring TestNG with: org.apache.maven.surefire.testng.conf.TestNG652Configurator@60acc399
Tests run: 1, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 2.326 sec <<< FAILURE!
shouldMapHashMapToFoo(org.me.modelmapper.MapperTest)  Time elapsed: 0.186 sec  <<< FAILURE!
org.modelmapper.ConfigurationException: ModelMapper configuration errors:

1) Invalid source method java.util.HashMap.get(). Ensure that method has zero parameters and does not return void.

2) Invalid source method java.util.HashMap.get(). Ensure that method has zero parameters and does not return void.

2 errors
    at org.modelmapper.internal.Errors.throwConfigurationExceptionIfErrorsExist(Errors.java:241)
    at org.modelmapper.internal.ExplicitMappingBuilder.visitPropertyMap(ExplicitMappingBuilder.java:228)
    at org.modelmapper.PropertyMap.configure(PropertyMap.java:380)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.modelmapper.internal.ExplicitMappingBuilder.build(ExplicitMappingBuilder.java:194)
    at org.modelmapper.internal.TypeMapImpl.addMappings(TypeMapImpl.java:72)
    at org.modelmapper.internal.TypeMapStore.getOrCreate(TypeMapStore.java:101)
    at org.modelmapper.ModelMapper.addMappings(ModelMapper.java:93)
    at org.me.modelmapper.MapperTest.shouldMapHashMapToFoo(MapperTest.java:354)


Results :

Failed tests:   shouldMapHashMapToFoo(org.me.modelmapper.MapperTest): ModelMapper configuration errors:
(..)

Tests run: 1, Failures: 1, Errors: 0, Skipped: 0
4

2 回答 2

11

它是自动映射的。您不需要配置任何映射。这将起作用：

@Test
public void shouldMapHashMapToFoo() {
    HashMap<String, String> map = new HashMap<>();
    map.put("a", "aaaa");
    map.put("b", "bbbb");

    Foo foo = modelMapper.map(map, Foo.class);

    Assert.assertEquals(foo.getA(), map.get("a"));
    Assert.assertEquals(foo.getB(), map.get("b"));

}

编辑： 如果您需要将 HashMap 映射到更复杂的结构，您始终可以使用“中间”类。

  public static class Bar
  {
    private String Z;
    private String W;

    public String getZ()
    {
      return Z;
    }

    public void setZ(String z)
    {
      Z = z;
    }

    public String getW()
    {
      return W;
    }

    public void setW(String w)
    {
      W = w;
    }
  }

  @Test
  public void shouldMapHashMapToFoo()
  {
    HashMap<String, String> map = new HashMap<>();
    map.put("z", "aaaa");
    map.put("w", "bbbb");

    Bar bar = modelMapper.map(map, Bar.class);

    PropertyMap<Bar, Foo> barToFooMap = new PropertyMap<Bar, Foo>()
    {
      @Override
      protected void configure()
      {
        map().setA(source.getZ());
        map().setB(source.getW());
      }

    };
    modelMapper.addMappings(barToFooMap);

    Foo foo = modelMapper.map(bar, Foo.class);

    Assert.assertEquals(foo.getA(), map.get("z"));
    Assert.assertEquals(foo.getB(), map.get("w"));
  }
于 2014-09-26T08:44:41.080 回答
0

需要注意的是，当从映射映射到对象时，单词的大小写会被忽略，例如：

map.put("test","0") & map.put("teSt","0") will work
于 2019-03-26T16:25:57.673 回答