本文内容大多基于官方文档和网上前辈经验总结，经过个人实践加以整理积累，仅供参考。

Google Gson 支持自定义规则过滤字段，使用 GsonBuilder 类的 addSerializationExclusionStrategy 方法处理序列化过程中的字段过滤，使用 addDeserializationExclusionStrategy 方法处理反序列化过程中的字段过滤。这两个方法都接收 com.google.gson.ExclusionStrategy 接口类型参数

示例

1 addSerializationExclusionStrategy

(1) 基于 @Expose 注解过滤

POJO 类

class GsonObject {
    public String field1 = "FIELD_1";
    @Expose(serialize = true, deserialize = false)
    public String field2 = "FIELD_2";
    @Expose(serialize = false, deserialize = true)
    public String field3 = "FIELD_3";
    public String field4 = "FIELD_4";

    @Override
    public String toString() {
        return "GsonObject [field1=" + field1 + ", field2=" + field2 + ", field3=" + field3 + ", field4=" + field4
                + "]";
    }
}

测试代码：

@Test
public void test() throws IOException {
    Gson gson = new GsonBuilder()
        .addSerializationExclusionStrategy(new ExclusionStrategy() {
            @Override
            public boolean shouldSkipField(FieldAttributes arg0) {
                Expose expose = arg0.getAnnotation(Expose.class);
                if (expose != null && expose.deserialize() == false) {
                    return true;
                }
                return false;
            }
            @Override
            public boolean shouldSkipClass(Class<?> arg0) {
                return false;
            }
        }).create();
    System.out.println(gson.toJson(new GsonObject()));
}

运行结果：

(2) 基于字段名过滤

测试代码：

@Test
public void test() throws IOException {
    Gson gson = new GsonBuilder()
        .addSerializationExclusionStrategy(new ExclusionStrategy() {
            @Override
            public boolean shouldSkipField(FieldAttributes arg0) {
                if (arg0.getName().equals("field4")) {
                    return true;
                }
                return false;
            }
            @Override
            public boolean shouldSkipClass(Class<?> arg0) {
                return false;
            }
        }).create();
    System.out.println(gson.toJson(new GsonObject()));
}

运行结果：

(3) 基于字段类型过滤

POJO 类

class GsonObject {
    public String field1 = "FIELD_1";
    public String field2 = "FIELD_2";
    public String field3 = "FIELD_3";
    public String field4 = "FIELD_4";
    public int field5 = 5;
    public double field6 = 6.0;
    public boolean field7 = false;

    @Override
    public String toString() {
        return "GsonObject [field1=" + field1 + ", field2=" + field2 + ", field3=" + field3 + ", field4=" + field4
            + ", field5=" + field5 + ", field6=" + field6 + ", field7=" + field7 + "]";
    }
}

测试代码：

@Test
public void test() throws IOException {
    Gson gson = new GsonBuilder()
        .setVersion(1)
        .addSerializationExclusionStrategy(new ExclusionStrategy() {
            @Override
            public boolean shouldSkipField(FieldAttributes arg0) {
                return false;
            }
            @Override
            public boolean shouldSkipClass(Class<?> arg0) {
                return (arg0 == double.class || arg0 == Double.class);
            }
        }).create();
    System.out.println(gson.toJson(new GsonObject()));
}

运行结果：

2 addDeserializationExclusionStrategy

(1) 基于 @Expose 注解过滤

POJO 类

class GsonObject {
    private String field1;
    @Expose(serialize = true, deserialize = false)
    private String field2;
    @Expose(serialize = false, deserialize = true)
    private String field3;
    private String field4;

    public String getField1() {
        return field1;
    }

    public void setField1(String field1) {
        this.field1 = field1;
    }

    public String getField2() {
        return field2;
    }

    public void setField2(String field2) {
        this.field2 = field2;
    }

    public String getField3() {
        return field3;
    }

    public void setField3(String field3) {
        this.field3 = field3;
    }

    public String getField4() {
        return field4;
    }

    public void setField4(String field4) {
        this.field4 = field4;
    }

    @Override
    public String toString() {
        return "GsonObject [field1=" + field1 + ", field2=" + field2 + ", field3=" + field3 + ", field4=" + field4
                + "]";
    }

}

测试代码：

@Test
public void test() throws IOException {
    Gson gson = new GsonBuilder()
        .addDeserializationExclusionStrategy(new ExclusionStrategy() {
            @Override
            public boolean shouldSkipField(FieldAttributes arg0) {
                Expose expose = arg0.getAnnotation(Expose.class);
                if (expose != null && expose.deserialize() == true) {
                    return true;
                }
                return false;
            }
            @Override
            public boolean shouldSkipClass(Class<?> arg0) {
                return false;
            }
        }).create();
    String gsonStr = "{\"field1\":\"FIELD_A\"," 
        + "\"field2\":\"FIELD_B\"," 
        + "\"field3\":\"FIELD_C\"," 
        + "\"field4\":\"FIELD_D\"}";
    System.out.println(gson.fromJson(gsonStr, GsonObject.class));
}

运行结果：

(2) 基于字段名过滤

测试代码：

@Test
public void test() throws IOException {
    Gson gson = new GsonBuilder()
        .addDeserializationExclusionStrategy(new ExclusionStrategy() {
            @Override
            public boolean shouldSkipField(FieldAttributes arg0) {
                if (arg0.getName().equals("field4")) {
                    return true;
                }
                return false;
            }
            @Override
            public boolean shouldSkipClass(Class<?> arg0) {
                return false;
            }
        }).create();
    String gsonStr = "{\"field1\":\"FIELD_A\"," 
        + "\"field2\":\"FIELD_B\"," 
        + "\"field3\":\"FIELD_C\"," 
        + "\"field4\":\"FIELD_D\"}";
    System.out.println(gson.fromJson(gsonStr, GsonObject.class));
}

运行结果：

(3) 基于字段类型过滤

POJO 类

class GsonObject {
    private String field1;
    private String field2;
    private String field3;
    private String field4;
    private int field5;
    private double field6;
    private boolean field7;

    public String getField1() {
        return field1;
    }

    public void setField1(String field1) {
        this.field1 = field1;
    }

    public String getField2() {
        return field2;
    }

    public void setField2(String field2) {
        this.field2 = field2;
    }

    public String getField3() {
        return field3;
    }

    public void setField3(String field3) {
        this.field3 = field3;
    }

    public String getField4() {
        return field4;
    }

    public void setField4(String field4) {
        this.field4 = field4;
    }

    public int getField5() {
        return field5;
    }

    public void setField5(int field5) {
        this.field5 = field5;
    }

    public double getField6() {
        return field6;
    }

    public void setField6(double field6) {
        this.field6 = field6;
    }

    public boolean isField7() {
        return field7;
    }

    public void setField7(boolean field7) {
        this.field7 = field7;
    }

    @Override
    public String toString() {
        return "GsonObject [field1=" + field1 + ", field2=" + field2 + ", field3=" + field3 + ", field4=" + field4
            + ", field5=" + field5 + ", field6=" + field6 + ", field7=" + field7 + "]";
    }
}

测试代码：

@Test
public void test() throws IOException {
    Gson gson = new GsonBuilder()
        .setVersion(1)
        .addDeserializationExclusionStrategy(new ExclusionStrategy() {
            @Override
            public boolean shouldSkipField(FieldAttributes arg0) {
                return false;
            }
            @Override
            public boolean shouldSkipClass(Class<?> arg0) {
                return (arg0 == double.class || arg0 == Double.class);
            }
        }).create();
    String gsonStr = "{\"field1\":\"FIELD_A\"," 
        + "\"field2\":\"FIELD_B\"," 
        + "\"field3\":\"FIELD_C\"," 
        + "\"field4\":\"FIELD_D\"," 
        + "\"field5\":55," 
        + "\"field6\":99.99," 
        + "\"field7\":true}";
    System.out.println(gson.fromJson(gsonStr, GsonObject.class));
}

运行结果：