Cargo.toml：

x
[dependencies]
serde = { version = "1.0.130", features = ["derive"] }
serde_json = "1.0"
serde_yaml = "0.9.13"
anyhow = "1.0.55"

src/main.rs：

use anyhow::{anyhow, Result};
use serde_json::Value;

fn main() -> Result<()> {
    let json_strings = r#"{"a": 1}
{a: 2}
{"a": 3}"#;
    let result = json_strings
        .split("\n")
        .filter_map(|s| serde_json::from_str::<Value>(s).ok())
        .collect::<Vec<_>>();
    for item in &result {
        let a = item
            .get("a")
            .ok_or(anyhow!("miss field a"))?
            .as_u64()
            .ok_or(anyhow!("invalid type of field a"))?;
        println!("a: {}", a);
    }
    println!("{:?}", result);

    Ok(())
}