[{"fieldName":"activity_desc","fieldValue":"45","op":"=="},{"fieldName":"","fieldValue":"","op":"and"},{"fieldName":"activity_desc","fieldValue":"44","op":"<="}] 将类似于这样的json字符串 解析成对象 前面作为字段 中间作为条件 用java代码处理一下 请给出代码示例

可以使用Jackson库来解析JSON字符串，并使用Java对象来表示条件。下面是一个示例代码：

import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.util.List;

public class Condition {
    @JsonProperty("fieldName")
    private String fieldName;

    @JsonProperty("fieldValue")
    private String fieldValue;

    @JsonProperty("op")
    private String op;

    public String getFieldName() {
        return fieldName;
    }

    public void setFieldName(String fieldName) {
        this.fieldName = fieldName;
    }

    public String getFieldValue() {
        return fieldValue;
    }

    public void setFieldValue(String fieldValue) {
        this.fieldValue = fieldValue;
    }

    public String getOp() {
        return op;
    }

    public void setOp(String op) {
        this.op = op;
    }

    public static void main(String[] args) throws JsonProcessingException {
        String json = "[{\"fieldName\":\"activity_desc\",\"fieldValue\":\"45\",\"op\":\"==\"},{\"fieldName\":\"\",\"fieldValue\":\"\",\"op\":\"and\"},{\"fieldName\":\"activity_desc\",\"fieldValue\":\"44\",\"op\":\"<=\"}]";

        ObjectMapper mapper = new ObjectMapper();
        List<Condition> conditions = mapper.readValue(json, mapper.getTypeFactory().constructCollectionType(List.class, Condition.class));

        for (Condition condition : conditions) {
            System.out.println(condition.getFieldName() + " " + condition.getOp() + " " + condition.getFieldValue());
        }
    }
}

该代码定义了一个名为`Condition`的类，该类具有三个字段`fieldName`，`fieldValue`和`op`，这些字段分别代表条件中的字段名称，字段值和运算符。然后我们使用Jackson库将JSON字符串转换为`List<Condition>`对象，并遍历该对象来打印出每个条件的字段名，运算符和字段值。